MK3.9S

<p><strong>MK4 to MK4S upgrade <br /></strong></p>
<p>The current lead time is <strong>2-3 weeks </strong>for both xLCD versions.</p>
<table class="table" style="border-collapse: collapse; height: 330.828px; border-style: ridge; width: 100%;" border="1">
<tbody>
<tr style="height: 28.375px;">
<td style="width: 29.0798%; height: 28.375px; border-style: dotted; border-width: 1px; text-align: left;">Order week</td>
<td style="width: 29.2017%; height: 28.375px; border-style: dotted; border-width: 1px; text-align: left;">Order date</td>
<td style="width: 41.7185%; height: 28.375px; border-style: dotted; border-width: 1px; text-align: left;">Shipping estimate</td>
</tr>
<tr style="height: 33.25px;">
<td style="width: 29.0798%; border-style: dotted; border-width: 1px; text-align: left; height: 33.25px;">Week 33</td>
<td style="width: 29.2017%; border-style: dotted; border-width: 1px; text-align: left; height: 33.25px;">starts August 12, 2024</td>
<td style="width: 41.7185%; height: 33.25px; border-style: dotted; border-width: 1px; text-align: left;" rowspan="2">Already shipped</td>
</tr>
<tr style="height: 24.7344px;">
<td style="width: 29.0798%; border-style: dotted; border-width: 1px; text-align: left; height: 24.7344px;">Week 34</td>
<td style="width: 29.2017%; border-style: dotted; border-width: 1px; text-align: left; height: 24.7344px;">starts August 19, 2024</td>
</tr>
<tr style="height: 24.7344px;">
<td style="width: 29.0798%; border-style: dotted; border-width: 1px; text-align: left; height: 24.7344px;">Week 35</td>
<td style="width: 29.2017%; border-style: dotted; border-width: 1px; text-align: left; height: 24.7344px;">starts August 26, 2024</td>
<td style="width: 41.7185%; height: 101.203px; border-style: dotted; border-width: 1px; text-align: left;" rowspan="6">Currently shipping</td>
</tr>
<tr style="height: 24.7344px;">
<td style="width: 29.0798%; border-style: dotted; border-width: 1px; text-align: left; height: 24.7344px;">Week 36</td>
<td style="width: 29.2017%; border-style: dotted; border-width: 1px; text-align: left; height: 24.7344px;">starts September 2, 2024</td>
</tr>
<tr style="height: 27px;">
<td style="width: 29.0798%; border-style: dotted; border-width: 1px; text-align: left; height: 27px;">Week 37</td>
<td style="width: 29.2017%; border-style: dotted; border-width: 1px; text-align: left; height: 27px;">starts September 9, 2024</td>
</tr>
<tr style="height: 30px;">
<td style="width: 29.0798%; border-style: dotted; border-width: 1px; text-align: left; height: 30px;">Week 38</td>
<td style="width: 29.2017%; border-style: dotted; border-width: 1px; text-align: left; height: 30px;">starts September 16, 2024</td>
</tr>
<tr style="height: 27px;">
<td style="width: 29.0798%; border-style: dotted; border-width: 1px; text-align: left; height: 27px;">Week 39</td>
<td style="width: 29.2017%; border-style: dotted; border-width: 1px; text-align: left; height: 27px;">starts September 23, 2024</td>
</tr>
<tr style="height: 27px;">
<td style="width: 29.0798%; border-style: dotted; border-width: 1px; text-align: left; height: 27px;">Week 40</td>
<td style="width: 29.2017%; border-style: dotted; border-width: 1px; text-align: left; height: 27px;">starts September 30, 2024</td>
</tr>
<tr style="height: 21px;">
<td style="width: 29.0798%; border-style: dotted; border-width: 1px; text-align: left; height: 21px;">Week 41</td>
<td style="width: 29.2017%; border-style: dotted; border-width: 1px; text-align: left; height: 21px;">starts October 7, 2024</td>
<td style="width: 41.7185%; border-style: dotted; border-width: 1px; text-align: left; height: 84px;" rowspan="3">From week 47 (starts November 18, 2024)</td>
</tr>
<tr style="height: 21px;">
<td style="width: 29.0798%; border-style: dotted; border-width: 1px; text-align: left; height: 21px;">Week 42</td>
<td style="width: 29.2017%; border-style: dotted; border-width: 1px; text-align: left; height: 21px;">starts October 14, 2024</td>
</tr>
<tr style="height: 21px;">
<td style="width: 29.0798%; border-style: dotted; border-width: 1px; text-align: left; height: 21px;">Week 43</td>
<td style="width: 29.2017%; border-style: dotted; border-width: 1px; text-align: left; height: 21px;">starts October 21, 2024</td>
</tr>
<tr style="height: 21px;">
<td style="width: 29.0798%; border-style: dotted; border-width: 1px; text-align: left; height: 21px;">Week 44</td>
<td style="width: 29.2017%; border-style: dotted; border-width: 1px; text-align: left; height: 21px;">starts October 28, 2024</td>
<td style="width: 41.7185%; border-style: dotted; border-width: 1px; text-align: left;" rowspan="3">From week 48 (starts November 25, 2024)</td>
</tr>
<tr>
<td style="width: 29.0798%; border-style: dotted; border-width: 1px; text-align: left;">Week 45</td>
<td style="width: 29.2017%; border-style: dotted; border-width: 1px; text-align: left;">starts November 4, 2024</td>
</tr>
<tr>
<td style="width: 29.0798%; border-style: dotted; border-width: 1px; text-align: left;">Week 46</td>
<td style="width: 29.2017%; border-style: dotted; border-width: 1px; text-align: left;">starts November 11, 2024</td>
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</tbody>
</table>
<p></p>
<p> </p>
<h3><span style="font-size: 20px;">Current lead time estimates for new orders</span></h3>
<p><span style="color: #e67e23;"><strong>Updated: November 11th, 2024 </strong></span></p>
<p><em>The dates are only an estimation at the date of update, specified above, and rely on the actual</em> production. <em>We're doing our best but please be aware that it can shift for the lead time products. We will update here and on the product pages accordingly.</em></p>
<p>The lead time estimate applies to standalone products, other products in the order may increase the lead time.</p>
<p>If you've ordered a product in a bundle, the lead time of the order is set based on the product in the bundle with the longest lead time.</p>
<p> </p>
<p></p>
<table class="table" style="border-collapse: collapse; height: 765.922px; border-style: ridge; width: 100%;" border="1">
<tbody>
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<td style="height: 27.922px; width: 48.3436%; border-style: dotted; border-width: 1px; text-align: center;">
<h4>Product</h4>
</td>
<td style="height: 27.922px; width: 51.6564%; border-style: dotted; border-width: 1px; text-align: center;">
<h4>Lead time</h4>
</td>
</tr>
<tr style="height: 72px;">
<td style="width: 48.3436%; border-style: dotted; border-width: 1px; text-align: center; height: 72px;">
<p><strong>Original Prusa XL Enclosure<br /></strong><em>(standalone)</em><strong><br /></strong></p>
</td>
<td style="width: 51.6564%; border-style: dotted; border-width: 1px; text-align: center; height: 72px;">
<p><strong>In stock</strong></p>
</td>
</tr>
<tr style="height: 72px;">
<td style="width: 48.3436%; border-style: dotted; border-width: 1px; text-align: center; height: 72px;">
<p><strong>Advanced Filtration System <br /></strong>(for Original Prusa Enclosure)</p>
</td>
<td style="width: 51.6564%; border-style: dotted; border-width: 1px; text-align: center; height: 72px;">
<p><strong>In stock</strong></p>
</td>
</tr>
<tr style="height: 72px;">
<td style="width: 48.3436%; border-style: dotted; border-width: 1px; text-align: center; height: 72px;">
<p><strong>MK4 to MK4S upgrade<br /></strong>/MK4S upgrade for versions with old xLCD</p>
</td>
<td style="width: 51.6564%; border-style: dotted; border-width: 1px; text-align: center; height: 72px;">
<p><strong>2-3 weeks</strong></p>
</td>
</tr>
<tr style="height: 72px;">
<td style="width: 48.3436%; border-style: dotted; border-width: 1px; text-align: center; height: 72px;">
<p><strong>MK3.9 to MK3.9S upgrade</strong></p>
</td>
<td style="width: 51.6564%; border-style: dotted; border-width: 1px; text-align: center; height: 72px;">
<p><strong>In stock</strong></p>
</td>
</tr>
<tr style="height: 51px;">
<td style="width: 48.3436%; border-style: dotted; border-width: 1px; text-align: center; height: 51px;">
<p><strong>MK3S/+ to MK4S upgrade</strong></p>
</td>
<td style="width: 51.6564%; border-style: dotted; border-width: 1px; text-align: center; height: 51px;">
<p><strong>2-3 weeks</strong></p>
</td>
</tr>
<tr>
<td style="width: 48.3436%; border-style: dotted; border-width: 1px; text-align: center;">
<p><strong>MK3S/+ to MK3.9S upgrade</strong></p>
</td>
<td style="width: 51.6564%; border-style: dotted; border-width: 1px; text-align: center;">
<p><strong>In stock</strong></p>
</td>
</tr>
<tr style="height: 51px;">
<td style="width: 48.3436%; border-style: dotted; border-width: 1px; text-align: center; height: 51px;">
<p><strong>MK3S/+ to MK3.5S upgrade</strong></p>
</td>
<td style="width: 51.6564%; border-style: dotted; border-width: 1px; text-align: center; height: 51px;">
<p><strong>In stock</strong></p>
</td>
</tr>
<tr style="height: 72px;">
<td style="width: 48.3436%; border-style: dotted; border-width: 1px; text-align: center; height: 72px;">
<p><strong>Original Prusa MMU3 upgrade kit (for MK4S/MK3.9S)</strong></p>
</td>
<td style="width: 51.6564%; border-style: dotted; border-width: 1px; text-align: center; height: 72px;">
<p><strong>1-2 weeks</strong></p>
</td>
</tr>
<tr style="height: 51px;">
<td style="width: 48.3436%; border-style: dotted; border-width: 1px; text-align: center; height: 51px;">
<p><strong>MMU3 assembled unit (for MK4S/MK3.9S) </strong></p>
</td>
<td style="width: 51.6564%; border-style: dotted; border-width: 1px; text-align: center; height: 51px;">
<p><strong>1-2 weeks</strong></p>
</td>
</tr>
<tr style="height: 51px;">
<td style="width: 48.3436%; border-style: dotted; border-width: 1px; text-align: center; height: 51px;">
<p><strong>MMU3 assembled unit (for MK4/MK3.9)</strong></p>
</td>
<td style="width: 51.6564%; border-style: dotted; border-width: 1px; text-align: center; height: 51px;">
<p><strong>In stock</strong></p>
</td>
</tr>
<tr style="height: 51px;">
<td style="width: 48.3436%; border-style: dotted; border-width: 1px; text-align: center; height: 51px;">
<p><strong>MMU3 assembled unit (for MK3.5S/MK3.5) </strong></p>
</td>
<td style="width: 51.6564%; border-style: dotted; border-width: 1px; text-align: center; height: 51px;">
<p><strong>In stock</strong></p>
</td>
</tr>
<tr style="height: 51px;">
<td style="width: 48.3436%; border-style: dotted; border-width: 1px; text-align: center; height: 51px;">
<p><strong>MMU3 assembled unit (for MK3S+) </strong></p>
</td>
<td style="width: 51.6564%; border-style: dotted; border-width: 1px; text-align: center; height: 51px;">
<p><strong>In stock</strong></p>
</td>
</tr>
<tr style="height: 72px;">
<td style="width: 48.3436%; border-style: dotted; border-width: 1px; text-align: center; height: 72px;">
<p><strong>Original Prusa MMU2S to MMU3 upgrade<br />for MK4S/MK3.9S</strong></p>
</td>
<td style="width: 51.6564%; border-style: dotted; border-width: 1px; text-align: center; height: 72px;">
<p><strong>1-2 weeks</strong></p>
</td>
</tr>
</tbody>
</table>
<p>You can find your order shipping date in the order detail section in our shop.</p>
<div class="note-callout">All products purchased in our <a href="https://shop.prusa3d.com/">online store</a> are currently being shipped from the<strong> Czech Republic, </strong>a member state of the <strong>European Union, customs charges may apply for shipments to countries outside of the EU!</strong> Please see our advisory article <a href="http://help.prusa3d.com/article/vat-value-added-tax-customs-fees_1505#orders-outside-eu">here</a>.</div>

Shipping information

Infill patterns

<div class="warning-callout">This is an&nbsp;<strong>advanced calibration</strong>, recommended only to&nbsp;<strong>experienced users</strong>.</div>
<p>The Extrusion Multiplier allows the fine-tuning of the extrusion flow rate - simply described as&nbsp;<strong>how much filament comes out of the nozzle</strong>. In other words, the&nbsp;<strong>Extrusion Multiplier</strong>&nbsp;setting in PrusaSlicer and the&nbsp;<strong>Flow rate</strong>&nbsp;setting in printer firmware are two ways to adjust the same thing, however, adjusting one of those two settings will not influence the value of the other.</p>
<p><strong>This procedure is not necessary with a new printer coming from the factory</strong>, but rather applies for specific applications and filaments. The ideal value is different for every type of material and every color. It can even differ from spool to spool. Bear this in mind if you change type and brand of filament often or use cheap no-name brands.</p>
<div class="note-callout">Total flow rate = <strong>Flow multiplier</strong> in firmware (M221) x <strong>Extrusion multiplier</strong> in PrusaSlicer. For those interested in diving deeper, PrusaSlicer uses the same <a href="https://manual.slic3r.org/advanced/flow-math">Flow math as Slic3r</a>.</div>
<h3><strong>How to spot an issue</strong></h3>
<p>This calibration is used to fix two common problems:</p>
<ul>
<li><strong>Overextrusion</strong> - Too much material is extruded (flow is too high). It causes scarring of bottom layers and unnecessary material buildup on top layers.</li>
<li><strong>Minor under extrusion</strong>&nbsp;- Not enough material is extruded (flow is too low). It causes small gaps that appear between layer lines or perimeters.</li>
</ul>
<p><img decoding="async" loading="lazy" src="https://cdn.help.prusa3d.com/wp-content/uploads/under-ok-over.jpg" sizes="100vw" srcset="https://cdn.help.prusa3d.com/wp-content/uploads/under-ok-over-600x282.jpg 600w, https://cdn.help.prusa3d.com/wp-content/uploads/under-ok-over-800x376.jpg 800w, https://cdn.help.prusa3d.com/wp-content/uploads/under-ok-over-300x141.jpg 300w, https://cdn.help.prusa3d.com/wp-content/uploads/under-ok-over-768x361.jpg 768w, https://cdn.help.prusa3d.com/wp-content/uploads/under-ok-over-1536x721.jpg 1536w" alt="" width="852" height="400"></p>
<p><strong>Overextrusion</strong> is a common problem with many filament brands. It's especially problematic when you're trying to glue two parts of the model. <strong>If the top layer is over extruded, you'll end up with an uneven surface that will prevent a seamless connection between the two pieces.</strong></p>
<h3><strong>How to do the calibration</strong></h3>
<p>In PrusaSlicer, navigate to <span class="key">Filament Settings</span> and look for Extrusion Multiplier. The default setting (for PLA) is 1, this value represents a percentage, 1 = 100%, 0.95 = 95% etc. Usually, the adjusted values can be between 0.9 and 1.1. To adjust it, simply rewrite the value.</p>
<p><img decoding="async" style="max-height: 200px; display: block; margin-left: auto; margin-right: auto;" src="https://cdn.help.prusa3d.com/wp-content/uploads/prusuki/prusuki-images/image-2019-1-15-12-55-6.png" data-hd-height="200px"></p>
<p>In the printer menu, during a print, go to the Tune menu and then choose Flow. Again, the usual values can range between 90 and 110, although that does not mean you can't go above or below that.</p>
<h4>Which method should I use?</h4>
<p>There are two methods you can use to calibrate the Extrusion Multiplier, and we'll cover both of them in this article:</p>
<ul>
<li><strong>Precise Method</strong>&nbsp; -&nbsp; using precision tools such as calipers or micrometers.</li>
<li><strong>Visual Method&nbsp;</strong>&nbsp;- an easy method based on observing the visual properties of your models.</li>
</ul>
<p>The choice of the method depends entirely on your preferences; in the end, both yield similar results. Even the visual method will enable you to have perfectly fitting parts with smooth &amp; flat top layers.</p>
<h4>Precise Method</h4>
<div class="note-callout">Please note that the following guide is based on <strong>default</strong> PrusaSlicer 0.4 nozzle profiles, with a layer height of 0.1mm - 0.2mm. This means that:<br />
- Nozzle size = 0.4<br />
- Extrusion width =&nbsp;0.45<br />
- Basic materials (PLA, ABS, PETG) Extrusion Multiplier = 1<br />
<strong>If you wish to calibrate the printer with a bigger/smaller nozzle or layer heights above 0.2, then you will need to adjust these values as well.</strong></div>
<ol>
<li>Download the <a href="https://cdn.help.prusa3d.com/wp-content/uploads/2021/04/cube-40-40-40.zip">Precision Method Cube STL</a>.</li>
<li>Slice it using the Vase Mode and your most-often used layer height and print it. You can find Vase mode (Print Settings →&nbsp; Layers and perimeters →&nbsp; Spiral vase).</li>
<li>Make three or more measurements in the middle of each wall and calculate the overall average thickness.</li>
<li>Calculate the extrusion multiplier using the following formula: <strong>Extrusion multiplier = (Extrusion width (0.45) / Average measured wall thickness)</strong>.</li>
<li>Adjust the Extrusion Multiplier in Filament Settings → Filament</li>
<li>Re-print the cube with new settings and go back to step 3 if necessary.</li>
</ol>
<p><img decoding="async" style="max-height: 220px; display: block; margin-left: auto; margin-right: auto;" src="https://cdn.help.prusa3d.com/wp-content/uploads/prusuki/prusuki-images/micrometer-small-jpg.JPG" height="400" data-hd-height="220px"></p>
<div class="warning-callout">Please note that cheap digital calipers may not be accurate enough to make reliable measurements of a single perimeter wall.</div>
<h4>Visual Method</h4>
<p>This method does not require any tools, only your sight. The point is to make sure your top layers are <strong>smooth</strong>, <strong>shiny,</strong> and without <strong>scarring or filament buildup</strong> near the perimeters.</p>
<p><img decoding="async" loading="lazy" style="display: block; margin-left: auto; margin-right: auto;" src="https://cdn.help.prusa3d.com/wp-content/uploads/destiky6.jpg" sizes="100vw" srcset="https://cdn.help.prusa3d.com/wp-content/uploads/destiky6-600x374.jpg 600w, https://cdn.help.prusa3d.com/wp-content/uploads/destiky6-800x499.jpg 800w, https://cdn.help.prusa3d.com/wp-content/uploads/destiky6-300x187.jpg 300w, https://cdn.help.prusa3d.com/wp-content/uploads/destiky6-768x479.jpg 768w, https://cdn.help.prusa3d.com/wp-content/uploads/destiky6-1536x958.jpg 1536w" alt="" width="641" height="400"></p>
<ol>
<li>Download the <a href="https://cdn.help.prusa3d.com/wp-content/uploads/2021/04/visual-method-cube.zip">Visual Method Cube.stl</a></li>
<li>Slice it using the default Prusa PLA presets at 0.20mm layer height and print it.</li>
<li>Inspect the top layer of your cube visually and with the tip of the finger.</li>
<li>If the top is under extruded or not smooth, then re-adjust the Extrusion Multiplier accordingly by 1-2%.</li>
<li>Repeat the steps above as long as needed.</li>
</ol>
<p>If there is&nbsp;<strong>too much material</strong>&nbsp;near the perimeters,&nbsp;<strong>decrease</strong>&nbsp;the Extrusion Multiplier value.</p>
<p><img decoding="async" style="max-height: 390px; margin-left: auto; margin-right: auto; display: block;" src="https://cdn.help.prusa3d.com/wp-content/uploads/prusuki/prusuki-images/buildu.jpg" data-hd-height="390px" data-hd-align="left"></p>
<p>If there are&nbsp;<strong>visible gaps</strong>&nbsp;between layer lines,&nbsp;<strong>increase</strong> the Extrusion Multiplier value. (Microscopic gaps near the perimeters are OK.)</p>
<p><img decoding="async" style="max-height: 430px; margin-left: auto; margin-right: auto; display: block;" src="https://cdn.help.prusa3d.com/wp-content/uploads/prusuki/prusuki-images/gaps.jpg" data-hd-height="430px" data-hd-align="left"></p>


Extrusion multiplier calibration

<p>Stringing or oozing, also known as "hairy prints", is the name given for when small strings of filament are left on a printed model. This usually happens when the filament keeps flowing from the nozzle while the extruder is moving to another object. You can see this as a marginal line of filament left between the objects.</p>
<p>This issue is caused by <strong>very high printing temperatures and/or using incorrect retraction settings</strong>. This can be solved by changing a couple of settings in PrusaSlicer and checking your hardware.</p>
<table style="border-collapse: collapse; width: 100%;" border="0">
<tbody>
<tr>
<td style="width: 48.8442%;"><img decoding="async" loading="lazy" src="https://cdn.help.prusa3d.com/wp-content/uploads/2022/02/90014ff5fc80d10b.jpg" sizes="(min-width: 1024px) 820px, 100vw" srcset="https://cdn.help.prusa3d.com/wp-content/uploads/2022/02/90014ff5fc80d10b-600x383.jpg 600w, https://cdn.help.prusa3d.com/wp-content/uploads/2022/02/90014ff5fc80d10b-800x511.jpg 800w, https://cdn.help.prusa3d.com/wp-content/uploads/2022/02/90014ff5fc80d10b-300x192.jpg 300w, https://cdn.help.prusa3d.com/wp-content/uploads/2022/02/90014ff5fc80d10b-768x490.jpg 768w, https://cdn.help.prusa3d.com/wp-content/uploads/2022/02/90014ff5fc80d10b-1536x981.jpg 1536w, https://cdn.help.prusa3d.com/wp-content/uploads/2022/02/90014ff5fc80d10b-2048x1308.jpg 2048w, https://cdn.help.prusa3d.com/wp-content/uploads/2022/02/90014ff5fc80d10b.jpg 1600w" alt="" width="400" height="255"></td>
<td style="width: 48.8442%;"><img decoding="async" loading="lazy" src="https://cdn.help.prusa3d.com/wp-content/uploads/2022/02/b1b72c32290b8c00.jpg" sizes="(min-width: 1024px) 820px, 100vw" srcset="https://cdn.help.prusa3d.com/wp-content/uploads/2022/02/b1b72c32290b8c00-600x400.jpg 600w, https://cdn.help.prusa3d.com/wp-content/uploads/2022/02/b1b72c32290b8c00-800x534.jpg 800w, https://cdn.help.prusa3d.com/wp-content/uploads/2022/02/b1b72c32290b8c00-300x200.jpg 300w, https://cdn.help.prusa3d.com/wp-content/uploads/2022/02/b1b72c32290b8c00-768x512.jpg 768w, https://cdn.help.prusa3d.com/wp-content/uploads/2022/02/b1b72c32290b8c00.jpg 1600w" alt="" width="400" height="267"></td>
</tr>
</tbody>
</table>
<h3>Stringing from material left on the nozzle</h3>
<p>If you print for a long time from a single type of filament, such as PET-G, the filament can create a thin layer in the nozzle. This can cause stringing as the strands of the filament stick to the surface of the print. Therefore, thoroughly clean the nozzle before printing and make sure that any dirt or remnants of previous filaments are removed from the nozzle.</p>
<div class="warning-callout">We highly recommend using our official (factory default) preset settings in PrusaSlicer. However, if you are printing with your own settings, make sure that you have the retraction settings configured correctly.</div>
<h3>PrusaSlicer settings</h3>
<p><img decoding="async" loading="lazy" style="display: block; margin-left: auto; margin-right: auto;" src="https://cdn.help.prusa3d.com/wp-content/uploads/2022/02/432d664dd4b64d78_painted.jpeg" sizes="(min-width: 1024px) 820px, 100vw" srcset="https://cdn.help.prusa3d.com/wp-content/uploads/2022/02/432d664dd4b64d78_painted-600x359.jpeg 600w, https://cdn.help.prusa3d.com/wp-content/uploads/2022/02/432d664dd4b64d78_painted-800x479.jpeg 800w, https://cdn.help.prusa3d.com/wp-content/uploads/2022/02/432d664dd4b64d78_painted-300x179.jpeg 300w, https://cdn.help.prusa3d.com/wp-content/uploads/2022/02/432d664dd4b64d78_painted-768x459.jpeg 768w, https://cdn.help.prusa3d.com/wp-content/uploads/2022/02/432d664dd4b64d78_painted-1536x919.jpeg 1536w, https://cdn.help.prusa3d.com/wp-content/uploads/2022/02/432d664dd4b64d78_painted.jpeg 1600w" alt="" width="700" height="419"></p>
<p>You should start by checking a parameter known as Retraction. What does retraction do? When the extruder has finished printing one section/object of your g-code, the filament is pulled back into the nozzle. Once the extruder moves to the next location the printing process continues – the filament is pushed back out and it starts extruding from the nozzle again. Retraction settings can be found in PrusaSlicer in <em>Printer Settings -&gt; Extruder 1</em>.</p>
<p>Flexible filaments usually need longer retractions, because the material stretches while being pulled back to the nozzle. Flexible materials are a special case and can need a lot of tweaking and tuning.</p>
<p><strong>The retraction settings are:</strong></p>
<ul>
<li><strong>Retraction length:</strong> Amount that the filament is pulled back when a retraction is triggered. <strong>On the MK2.5/S and MK3/S/+, the retraction length should be a maximum of 2 mm.</strong></li>
</ul>
<div class="tip-callout">Due to the Bowden extruder, the retraction length of the Original Prusa MINI/MINI+ presets are much longer (default 3.2 mm).</div>
<ul>
<li><strong>Lift z:</strong> lifts the extruder during movement. Having this setting lower will improve stringing. Note that disabling this feature may cause the nozzle to hit the printed part.<strong><br /></strong></li>
<li><strong>Retraction Speed:</strong> Extruder motor speed on retraction. A higher value improves stringing, but if it is too high it may skip steps in the motor.</li>
<li><strong>Minimum travel after retraction:</strong> Amount of move that will trigger a retraction (mm). The preset number in PrusaSlicer is 1 mm, which is a low amount. Having this number higher will get lower printing times, but increase oozing and stringing.</li>
<li><strong>Retract on layer change:</strong> Activates retraction when the layer changes to the next one. It is recommended to leave this option on.</li>
<li><strong>Wipe while retracting:</strong> Moves the nozzle (wipe) while the retraction is happening. It is recommended to leave this option on.</li>
<li><strong>Retract amount before wiping:</strong> This option does a quick retract before doing the wiping movement. More suitable for the Original Prusa MINI/MINI+.</li>
</ul>
<p><strong>Other settings that affect retraction:</strong></p>
<ul>
<li><strong>Only retract when crossing perimeters:</strong> <em>(Print settings -&gt; Infill -&gt; Advanced):</em> Disables retraction when the travel path does not exceed the upper layer's perimeter. Any oozing that happens will be within the walls and should be invisible.</li>
<li><strong>Avoid crossing perimeters:</strong> <em>(Print settings -&gt; Layers and perimeters -&gt; Quality):</em> Optimize travel moves in order to minimize the crossing of perimeters. This will lower the stringing amount, especially in the MINI/MINI+.</li>
<li><strong><a href="http://help.prusa3d.com/article/sequential-printing_124589">Sequential printing</a>:</strong> <em>(Print settings -&gt; Output options -&gt; Sequential printing):</em> Printing each object individually has a smaller chance of causing stringing between the parts. When using this feature, PrusaSlicer will warn you of any possibility of the extruder colliding with an already printed part, but follow the print closely.</li>
<li><strong>Nozzle temperature:</strong> <em>(Filament settings -&gt; Filament -&gt; Nozzle):</em> Lowering the temperature decreases the occurrence of strings. Try decreasing the nozzle temperature by 5 – 10°C and check whether there’s less stringing.</li>
</ul>
<h3>Filament</h3>
<p>Try using a different spool than the one that is causing the stringing. The filament might have gathered moisture, which will cause a lot of stringing.</p>
<h3>Hotend</h3>
<p>Stringing in the nozzle might be caused by a heat dissipation issue in the nozzle. Try <a href="http://help.prusa3d.com/guide/how-to-replace-a-heatbreak-heatsink-heaterblock-mk3s-mk3s-mk2-5s-mmu2s_16104">re-applying thermal paste</a> on the threads between the heatbreak and the heatsink.</p>
<p>If you have recently changed any component in the hotend, it is also possible that some individual parts are not in place. Go over the assembly of the hotend and check for any parts that may be different from the <a href="http://help.prusa3d.com/guide/how-to-replace-a-heatbreak-heatsink-heaterblock-mk3s-mk3s-mk2-5s-mmu2s_16104">instructions</a>.</p>
<h3>Enough settings, pass me my <strong>heat-gun!</strong></h3>
<p>If you don’t feel like tweaking any of the settings, well, then there is an alternative. You can get rid of the strings with a heat gun (or often with a lighter – but be very careful). Set your heat-gun to around 200 °C and aim at the strings for one or two seconds. This will melt the strings, and the printed object should remain undamaged. Do not leave the heat source on the printed model for longer than one or two seconds, as this may deform the part.</p>


Stringing and oozing

<div><strong><img decoding="async" loading="lazy" style="float: right;" src="https://cdn.help.prusa3d.com/wp-content/uploads/prusament-petg-prusa-orange-1kg.jpg" sizes="100vw" srcset="https://cdn.help.prusa3d.com/wp-content/uploads/prusament-petg-prusa-orange-1kg-400x400.jpg 400w, https://cdn.help.prusa3d.com/wp-content/uploads/prusament-petg-prusa-orange-1kg-600x600.jpg 600w, https://cdn.help.prusa3d.com/wp-content/uploads/prusament-petg-prusa-orange-1kg-300x300.jpg 300w, https://cdn.help.prusa3d.com/wp-content/uploads/prusament-petg-prusa-orange-1kg-768x768.jpg 768w" alt="" width="225" height="225"></strong></div>
<h3>Basic info</h3>
<div><strong>PETG</strong> is one of the most easily printable materials, it is <strong>inexpensive and suitable for beginners</strong>. Relatively high tenacity and temperature resistance make it <strong>suitable for printing technical parts</strong> (for example parts of our printers).</div>
<div>&nbsp;</div>
<div><strong>Recommended nozzle temperature:</strong> 230 °C for the first layer, 240 °C for the other layers</div>
<div>&nbsp;</div>
<div><strong>Recommended bed temperature:</strong> 85 °C for the first layer, 90 °C for the other layers</div>
<div>&nbsp;</div>
<div><strong>Heatbed:</strong> Using powder-coated TXT or satin sheet is highly recommended. Printing on smooth PEI surface might damage the sheet.</div>
<h3>Description</h3>
<div>
<p><a href="https://www.prusa3d.com/category/prusament-petg/"><strong data-stringify-type="bold">PETG</strong></a> (Polyethylene Terephthalate modified with Glycol) is a commonly used technical material, popular among 3D printer users for its <strong>low price and good printability</strong>. It’s tenacious, with good temperature resistance; PETG is most commonly used for printing various mechanical parts, holders, clamps, and waterproof parts (thanks to great layer adhesion).</p>
<p>PETG has a glossy surface, adheres greatly to a print sheet, and <strong>does not shrink or warp</strong> (it has very little thermal expansion), therefore it’s suitable for printing large models. Plus, its high tenacity and flexibility often <strong>prevent it from breaking.</strong> Due to good temperature resistance, PETG parts are suitable both for interior and most exterior use (with temperatures below 80 °C). <strong>Parts of our printers are made of PETG!</strong></p>
<p>The letter G in PETG means that it’s modified with glycol during the manufacturing process. Glycol makes PET less brittle, easier to print, and more transparent for translucent prints. Of course, you can print also with PET filaments without glycol. However, printing with only PET is challenging and does not offer any advantage whatsoever.</p>
<div class="warning-callout">Even though PETG in itself may be considered <a href="http://help.prusa3d.com/article/food-safe-fdm-printing_112313">food-safe</a>, it consists of layers, as every 3D print, in which bacteria can grow over time. You can prevent this by applying a <strong>food-safe(epoxy) coating.</strong> Also, a stainless-steel nozzle should be used for if food is the intended application.</div>
<p>Although <strong>PETG</strong> is frequently used in <strong>food industry</strong> and is considered <strong>food-safe</strong>, we do not recommend it (or any other filament) for printing dishes or other stuff that comes into direct contact with food. The main reason is tiny print layer surface grooves that can support numerous bacterial colonies. But if you still want 3D printed dishes, we suggest <strong>applying a special layer</strong> that seals the surface (food-safe coating) and printing with a clean steel nozzle.</p>
<p>Some of the manufacturers <strong>enrich PETG with various additives</strong> and sell these materials under different names. For example, Spoolworks EDGE by E3D is modified PET/Copolyester Blend with additives. The goal is to acquire better visual qualities, surface and layer adhesion, etc.</p>
<p>To compare supported material properties, see our <a href="https://help.prusa3d.com/en/materials">material table.</a></p>
</div>
<table class="striped">
<tbody>
<tr>
<th>
<p>Pros</p>
</th>
<th>
<p>Cons</p>
</th>
</tr>
<tr>
<td>
<p>✔ Easy to print</p>
</td>
<td>
<p>✖ Possibility of stringing</p>
</td>
</tr>
<tr>
<td>
<p>✔ Good layer adhesion</p>
</td>
<td>
<p>✖ Poor bridging and overhangs</p>
</td>
</tr>
<tr>
<td>
<p>✔ Tough and durable</p>
</td>
<td>
<p>✖ Not great for printing detailed parts</p>
</td>
</tr>
<tr>
<td>
<p>✔ Low warping</p>
</td>
<td>
<p>✖ Bonds strongly to the print surface</p>
</td>
</tr>
<tr>
<td>✔ High temperature-resistance</td>
<td>
<p>✖ Soluble in dangerous chemicals</p>
</td>
</tr>
<tr>
<td>✔ Water and humidity resistant</td>
<td>
<p>✖ Supports are hard to remove</p>
</td>
</tr>
</tbody>
</table>
<h3>Best use</h3>
<p>PETG is used universally but is especially suitable for mechanical parts for both indoor and outdoor use. We use PETG to print parts for our printers! Plastic bottles are also made from this kind of material.</p>
<h3>Tips for successful printing</h3>
<p><strong>Temperature settings and cooling</strong></p>
<p>Unlike PLA, <strong>PETG requires a heated bed (85 °C).</strong> Its bridging- and overhang-behavior is usually worse, plus it is prone to stringing. Stringing can be moderated with higher retractions and lower nozzle temperature, but we suggest <strong>using the PrusaSlicer profiles that should work fine.</strong> It’s important to <strong>cool the PETG print</strong> - this helps to keep the model detailed and prevents stringing and oozing. But if you want the model to be as tough as possible, try to turn off the print fan. Higher filament temperature improves merging between layers which leads to better mechanical resistance. Otherwise, we recommend printing the first few layers with the print fan off to prevent deformation, then with the fan running at half its power.</p>
<div class="warning-callout"><strong>Do not print on the smooth PEI sheet</strong> as the adhesion may be too strong!</div>
<p><strong>Print surface preparation</strong></p>
<p>Make sure the print surface is clean, as described in <a href="http://help.prusa3d.com/article/first-layer-issues_1804">our dedicated article</a>. It is advisable to use one of the <strong>powder-coated print sheets. Do not print on the smooth PEI sheet</strong> as the adhesion may be too strong! If you decide to use the smooth PEI sheet anyway, apply a glue stick on it before printing.</p>
<p><strong>Adding more perimeters for more solid parts</strong></p>
<p>If you want to print truly solid parts, <strong>try to increase the number of perimeters</strong> instead of adding more infill.</p>
<h3>Postprocessing</h3>
<p>PETG can be easily sanded both dry and wet.</p>
<p><strong>Dissolving PETG</strong></p>
<p><strong>Dissolving and smoothing PETG</strong> is possible only in a laboratory by skilled lab workers using <strong>dangerous chemicals</strong> (Dichloromethane).</p>
<h3>Sample prints</h3>
<table style="border-collapse: collapse; width: 100%; height: 954px;" border="0">
<tbody>
<tr style="height: 300px;">
<td style="width: 48.805%; height: 300px;"><img decoding="async" loading="lazy" src="https://cdn.help.prusa3d.com/wp-content/uploads/prusament-petg-prusa-orange-1kg-1-1.jpg" sizes="100vw" srcset="https://cdn.help.prusa3d.com/wp-content/uploads/prusament-petg-prusa-orange-1kg-1-1-400x400.jpg 400w, https://cdn.help.prusa3d.com/wp-content/uploads/prusament-petg-prusa-orange-1kg-1-1-600x600.jpg 600w, https://cdn.help.prusa3d.com/wp-content/uploads/prusament-petg-prusa-orange-1kg-1-1-300x300.jpg 300w, https://cdn.help.prusa3d.com/wp-content/uploads/prusament-petg-prusa-orange-1kg-1-1-768x768.jpg 768w" alt="" width="800" height="800"></td>
<td style="width: 48.805%; height: 300px;"><img decoding="async" loading="lazy" src="https://cdn.help.prusa3d.com/wp-content/uploads/prusament-petg-jet-black-1kg.jpg" sizes="100vw" srcset="https://cdn.help.prusa3d.com/wp-content/uploads/prusament-petg-jet-black-1kg-400x400.jpg 400w, https://cdn.help.prusa3d.com/wp-content/uploads/prusament-petg-jet-black-1kg-600x600.jpg 600w, https://cdn.help.prusa3d.com/wp-content/uploads/prusament-petg-jet-black-1kg-300x300.jpg 300w, https://cdn.help.prusa3d.com/wp-content/uploads/prusament-petg-jet-black-1kg-768x768.jpg 768w" alt="" width="800" height="800"></td>
</tr>
<tr style="height: 18px;">
<td style="width: 48.805%; height: 18px; text-align: center;"><em>MMU (Multi-Material Unit)</em></td>
<td style="width: 48.805%; height: 18px; text-align: center;"><em>Electronics cover and other printer parts</em></td>
</tr>
<tr style="height: 300px;">
<td style="width: 48.805%; height: 300px;"><img decoding="async" loading="lazy" src="https://cdn.help.prusa3d.com/wp-content/uploads/prusament-petg-prusa-orange-1kg-2.jpg" sizes="100vw" srcset="https://cdn.help.prusa3d.com/wp-content/uploads/prusament-petg-prusa-orange-1kg-2-400x400.jpg 400w, https://cdn.help.prusa3d.com/wp-content/uploads/prusament-petg-prusa-orange-1kg-2-600x600.jpg 600w, https://cdn.help.prusa3d.com/wp-content/uploads/prusament-petg-prusa-orange-1kg-2-300x300.jpg 300w, https://cdn.help.prusa3d.com/wp-content/uploads/prusament-petg-prusa-orange-1kg-2-768x768.jpg 768w" alt="" width="800" height="800"></td>
<td style="width: 48.805%; height: 300px;"><img decoding="async" loading="lazy" src="https://cdn.help.prusa3d.com/wp-content/uploads/prusament-petg-prusa-orange-1kg-3.jpg" sizes="100vw" srcset="https://cdn.help.prusa3d.com/wp-content/uploads/prusament-petg-prusa-orange-1kg-3-400x400.jpg 400w, https://cdn.help.prusa3d.com/wp-content/uploads/prusament-petg-prusa-orange-1kg-3-600x600.jpg 600w, https://cdn.help.prusa3d.com/wp-content/uploads/prusament-petg-prusa-orange-1kg-3-300x300.jpg 300w, https://cdn.help.prusa3d.com/wp-content/uploads/prusament-petg-prusa-orange-1kg-3-768x768.jpg 768w" alt="" width="800" height="800"></td>
</tr>
<tr style="height: 18px;">
<td style="width: 48.805%; height: 18px; text-align: center;"><em>Ukulele</em></td>
<td style="width: 48.805%; height: 18px; text-align: center;"><em>Various mechanical parts</em></td>
</tr>
<tr style="height: 300px;">
<td style="width: 48.805%; height: 300px; text-align: center;"><img decoding="async" loading="lazy" src="https://cdn.help.prusa3d.com/wp-content/uploads/prusament-petg-urban-grey-1kg-1.jpg" sizes="100vw" srcset="https://cdn.help.prusa3d.com/wp-content/uploads/prusament-petg-urban-grey-1kg-1-400x400.jpg 400w, https://cdn.help.prusa3d.com/wp-content/uploads/prusament-petg-urban-grey-1kg-1-600x600.jpg 600w, https://cdn.help.prusa3d.com/wp-content/uploads/prusament-petg-urban-grey-1kg-1-300x300.jpg 300w, https://cdn.help.prusa3d.com/wp-content/uploads/prusament-petg-urban-grey-1kg-1-768x768.jpg 768w" alt="" width="800" height="800"></td>
<td style="width: 48.805%; height: 300px; text-align: center;"><img decoding="async" loading="lazy" src="https://cdn.help.prusa3d.com/wp-content/uploads/prusament-petg-urban-grey-1kg.jpg" sizes="100vw" srcset="https://cdn.help.prusa3d.com/wp-content/uploads/prusament-petg-urban-grey-1kg-400x400.jpg 400w, https://cdn.help.prusa3d.com/wp-content/uploads/prusament-petg-urban-grey-1kg-600x600.jpg 600w, https://cdn.help.prusa3d.com/wp-content/uploads/prusament-petg-urban-grey-1kg-300x300.jpg 300w, https://cdn.help.prusa3d.com/wp-content/uploads/prusament-petg-urban-grey-1kg-768x768.jpg 768w" alt="" width="800" height="800"></td>
</tr>
<tr style="height: 18px;">
<td style="width: 48.805%; height: 18px; text-align: center;"><em>Electronic parts</em></td>
<td style="width: 48.805%; height: 18px; text-align: center;"><em>Boxes and organizers</em></td>
</tr>
</tbody>
</table>


PETG

Original Prusa i3 MK3/MK3S/MK3S+ to MK4S/MK3.9S upgrade

Original Prusa MK4/MK3.9 to MK4S/MK3.9S upgrade

Assembly manuals

Basic calibration

Advanced calibration

All information you need to know to learn how to calibrate your 3D printer to achieve perfect prints.

Calibration

Printer description

Printer features

FAQs and other useful information you might be interested in before or after making your purchase at shop.prusa3d.com

General Information

Basic overview of your 3D printer and it's features, plus general Prusa Research info.

About your printer

3D models

Material guide

Printer maintenance

Prusa Connect & PrusaLink

In this section, you can find material guides, printer troubleshooting and general info about using your printer.

Using the printer

Print Quality Troubleshooting

QR Error codes

Printer troubleshooting

Description of how to recognize and solve common problems, especially hardware and electronics related.

Troubleshooting

Nozzles

Octoprint

Learn about different nozzles, Raspberry Pi connection, Octoprint and more.

3rd party accessories & Other projects

About PrusaSlicer

Configuration and profiles

User interface

Input/output

Top toolbar

Print settings

Filament settings

Advanced features

The official documentation for the PrusaSlicer slicing software. From basic configuration to advanced settings like modifier meshes.

PrusaSlicer

1. Introduction

1a. Parts check

2. Upgrading the Y-axis

3. Upgrading the xLCD

1b. Printer disassembly

1c. Parts preparation

4. Upgrading the Nextruder

2. Frame assembly

4B. Upgrading the Nextruder (MMU3)

3. X-axis & X-carriage assembly

5. Upgrading the connectivity

6. Preflight check

4. Z-axis assembly

Manual changelog

5. Nextruder assembly

6. xLCD assembly

7. Y-carriage & Heatbed assembly

8. Preflight check

<p>Loose belts would cause a printer to malfunction and prevent proper printing. It can cause <a href="http://help.prusa3d.com/article/layer-shifting_2020">Layer shifting</a>, <a href="http://help.prusa3d.com/article/ghosting_1801">Ghosting</a>, or other print abnormalities like getting an irregular shape instead of a perfect circle when printing a cylinder. <strong>The Y-axis belt is located under the heatbed, X-axis belt moves the print head. All adjustments are done with the 2.5mm Allen key. </strong></p>
<h3>Checking belt tension</h3>
<h4>New procedure - Belt tuner app</h4>
<p>For checking the belt tightness using our <a href="https://belt.connect.prusa3d.com/">belt tuner</a>, follow the instructions in the video below.</p>
<p style="text-align: center;"><iframe src="https://www.youtube.com/embed/oeq2MVxE_H8" width="560" height="314" allowfullscreen="allowfullscreen" loading="lazy"></iframe></p>
<h4>Old procedure</h4>
<p>On MK3/S/+, run the Self-test or the Belt test, from Calibration on the LCD. Then check <em>LCD-menu -&gt; Support -&gt; Belt-status.</em> You want the number between <strong>260 and 290 (275~)</strong>. <em>The lower the number, the tighter the belt is. Imagine it is a fictive count of teeth in circulation.</em></p>
<div class="tip-callout">For the MK2.5 and MK2.5S, a great way to check whether your belt is at the correct tension is to print this <a href="https://www.prusaprinters.org/prints/46639-tension-meter-for-the-gt2-belts-of-i3-mk3s-or-prus">Tension Meter for the GT2 belts</a>.</div>
<p>Another way is to use the technique described in <a href="http://help.prusa3d.com/guide/5-e-axis-assembly_28536#30816">this step</a> of the assembly manual to test if the pulley is correctly tightened and if the belt is not too loose. Hold the X-axis motor shaft with pliers (take advantage of the flat part of the shaft) to fix it in place (<strong><span style="color: #b96ad9;">purple circle</span></strong>), then try to move the extruder by hand. <strong>You should see no slack on the belt as a result of pushing on the extruder.</strong> The same procedure can be applied to test the Y-axis pulley and belt.</p>
<p><img decoding="async" style="display: block; margin-left: auto; margin-right: auto;" src="https://cdn.help.prusa3d.com/wp-content/uploads/prusuki/prusuki-images/2019-08-21-16-07-05-f-jmg-pa-bdtv-ruqf-11-full-1600-1200.jpg" alt="" width="600" height="415" loading="lazy" /></p>
<h3>X-axis belt</h3>
<h4>Slight adjustments MK3S</h4>
<p>Loosen the two front-facing screws and make sure they have space to their right to move (<span style="color: #f1c40f;"><strong>yellow circles</strong></span>). While assisting with the rotation of the motor with your hand, tighten the M3x18 screw on top of the X-end-motor (<span style="color: #b96ad9;"><strong>purple arrow</strong></span>).</p>
<p>After each turn or two check the tension in the belt by pressing them together. For optimal performance, the belt must need some force to press together with your fingers (<span style="color: #2dc26b;">green arrows</span>). <strong>Move the extruder all the way to the X-end-idler and try the belt tension in the middle of the X-axis.</strong></p>
<p><img decoding="async" style="display: block; margin-left: auto; margin-right: auto;" src="https://cdn.help.prusa3d.com/wp-content/uploads/d1a9b24b68e0121e_painted.jpeg" sizes="100vw" srcset="https://cdn.help.prusa3d.com/wp-content/uploads/d1a9b24b68e0121e_painted-533x400.jpeg 533w, https://cdn.help.prusa3d.com/wp-content/uploads/d1a9b24b68e0121e_painted-800x600.jpeg 800w, https://cdn.help.prusa3d.com/wp-content/uploads/d1a9b24b68e0121e_painted-300x225.jpeg 300w, https://cdn.help.prusa3d.com/wp-content/uploads/d1a9b24b68e0121e_painted-768x576.jpeg 768w, https://cdn.help.prusa3d.com/wp-content/uploads/d1a9b24b68e0121e_painted-1536x1152.jpeg 1536w" alt="" width="600" height="450" loading="lazy" /></p>
<h4>Slight adjustments MK3S+, MK3.5/S, MK3.9/S, MK4/S</h4>
<ol>
<li>Slightly release all the screws holding the motor, otherwise, the "tensioner" won't work as the motor must be able to move (left picture).</li>
<li>Using the ball end of the Allen key, start tightening the screw on the rear side of the X-end-motor, but after each turn or two check the tension in the belt (right picture).</li>
<li>When you achieve optimal tension, please tighten the screws again (left picture).</li>
</ol>
<table style="border-collapse: collapse; width: 100%;" border="0">
<tbody>
<tr>
<td style="width: 48.805%;"><img decoding="async" src="https://cdn.help.prusa3d.com/wp-content/uploads/2020/11/da45b9e5fe1a6ec4_painted.jpeg" sizes="100vw" srcset="https://cdn.help.prusa3d.com/wp-content/uploads/2020/11/da45b9e5fe1a6ec4_painted-533x400.jpeg 533w, https://cdn.help.prusa3d.com/wp-content/uploads/2020/11/da45b9e5fe1a6ec4_painted-800x600.jpeg 800w, https://cdn.help.prusa3d.com/wp-content/uploads/2020/11/da45b9e5fe1a6ec4_painted-300x225.jpeg 300w, https://cdn.help.prusa3d.com/wp-content/uploads/2020/11/da45b9e5fe1a6ec4_painted-768x576.jpeg 768w, https://cdn.help.prusa3d.com/wp-content/uploads/2020/11/da45b9e5fe1a6ec4_painted-1536x1152.jpeg 1536w" alt="" width="400" height="300" loading="lazy" /></td>
<td style="width: 48.9057%;"><img decoding="async" src="https://cdn.help.prusa3d.com/wp-content/uploads/2020/11/4d946176a9a518fc_painted.jpeg" sizes="100vw" srcset="https://cdn.help.prusa3d.com/wp-content/uploads/2020/11/4d946176a9a518fc_painted-533x400.jpeg 533w, https://cdn.help.prusa3d.com/wp-content/uploads/2020/11/4d946176a9a518fc_painted-800x600.jpeg 800w, https://cdn.help.prusa3d.com/wp-content/uploads/2020/11/4d946176a9a518fc_painted-300x225.jpeg 300w, https://cdn.help.prusa3d.com/wp-content/uploads/2020/11/4d946176a9a518fc_painted-768x576.jpeg 768w, https://cdn.help.prusa3d.com/wp-content/uploads/2020/11/4d946176a9a518fc_painted-1536x1152.jpeg 1536w" alt="" width="400" height="300" loading="lazy" /></td>
</tr>
</tbody>
</table>
<h4>Large adjustments MK3/S/+ or MK3.5/S</h4>
<p>If a slight adjustment is not sufficient you must adjust it at the belt holder. This is found on the back of the extruder and requires a little disassembly.</p>
<p>First, remove the two top screws from the motor-holder to let the belt have some slack in order to easier manipulate the belt.</p>
<ol>
<li>Snip the zip-ties on the back of the extruder (<span style="color: #e03e2d;"><strong>red arrows</strong></span>), which are securing the hotend wires <strong>and</strong> the ones securing the cable wrap.</li>
</ol>
<p><img decoding="async" style="display: block; margin-left: auto; margin-right: auto;" src="https://cdn.help.prusa3d.com/wp-content/uploads/Adjusting-belt-tension-MK3S-03.png" alt="" width="600" height="450" loading="lazy" /></p>
<ol start="2">
<li style="counter-increment: li 1;">Unscrew the 4 screws circled in the picture below.</li>
</ol>
<p><img decoding="async" style="display: block; margin-left: auto; margin-right: auto;" src="https://cdn.help.prusa3d.com/wp-content/uploads/Adjusting-belt-tension-MK3S-04.png" alt="" width="600" height="450" loading="lazy" /></p>
<ol start="3">
<li style="counter-increment: li 2;">Carefully pull the back plate loose, making sure the wires are safe, and turn the whole plate to the left or right.</li>
</ol>
<p><img decoding="async" style="display: block; margin-left: auto; margin-right: auto;" src="https://cdn.help.prusa3d.com/wp-content/uploads/Adjusting-belt-tension-MK3S-05.jpg" alt="" width="600" height="574" loading="lazy" /></p>
<ol start="4">
<li style="counter-increment: li 3;">You now have access to where you mount the belts. Put a mark on the belt with a pen or marker as close to the plastic part as possible, so you know how it was adjusted. Now, take out the belt from the mount and move it in 1-2 teeth.</li>
</ol>
<div class="tip-callout">It may be necessary to cut off the last tooth of the belt.</div>
<ol start="5">
<li style="counter-increment: li 4;">Place the back plate back on, secure the screws, starting with the center one for alignment, then put on new zip-ties.</li>
<li>Re-tighten the screws on the x-motor, securing it. Adjust it tighter if needed.</li>
</ol>
<h4>Large adjustments MK4/S, MK3.9/S</h4>
<ol>
<li>Loosen the three indicated screws covering the X-carriage. Carefully take out the X-cover-back.
<p><img decoding="async" style="display: block; margin-left: auto; margin-right: auto;" src="https://cdn.help.prusa3d.com/wp-content/uploads/2023/04/96f49f4aee27a2e4c92ed6d0dd7ff4c9_painted.jpeg" sizes="(min-width: 1024px) 820px, 100vw" srcset="Adjusting belt tension (review)" alt="" width="600" height="400" loading="lazy" /></p>
</li>
<li>You now have access to where you mount the belt. Put a mark on the belt with a pen or marker as close to the plastic part as possible, so you know how it was adjusted. Now, take out the belt from the mount and move it in 1-2 teeth.</li>
</ol>
<p><img decoding="async" style="display: block; margin-left: auto; margin-right: auto;" src="https://cdn.help.prusa3d.com/wp-content/uploads/2023/04/5d0b7637d19fdb682ff706171280e0fb.jpg" sizes="(min-width: 1024px) 820px, 100vw" srcset="Adjusting belt tension (review)" alt="" width="600" height="450" loading="lazy" /></p>
<h3>Y-axis belt</h3>
<h4>Slight adjustments</h4>
<p>On the front plate of the printer's frame, behind the LCD module, you will find the printed Y-axis belt idler. This is held by two M3X10 screws (<span style="color: #b96ad9;"><strong>purple arrow</strong></span>), going through the front plate.</p>
<p>If you have a gap between the idler part and the front plate of the frame (<span style="color: #236fa1;"><strong>blue arrows</strong></span>) you can tighten the belt by using your 2.5 mm Allen key to turn the screws clockwise (<span style="color: #b96ad9;"><strong>purple arrow</strong></span>), closing the gap.</p>
<p>The easiest way to access the screws is from below, by moving the printer to the edge of its table, with the LCD module sticking out. You now have access to the bolts from below the LCD module.</p>
<p><img decoding="async" style="display: block; margin-left: auto; margin-right: auto;" src="https://cdn.help.prusa3d.com/wp-content/uploads/73fa58fb081ffbfa_painted.jpeg" sizes="100vw" srcset="https://cdn.help.prusa3d.com/wp-content/uploads/73fa58fb081ffbfa_painted-583x400.jpeg 583w, https://cdn.help.prusa3d.com/wp-content/uploads/73fa58fb081ffbfa_painted-800x549.jpeg 800w, https://cdn.help.prusa3d.com/wp-content/uploads/73fa58fb081ffbfa_painted-300x206.jpeg 300w, https://cdn.help.prusa3d.com/wp-content/uploads/73fa58fb081ffbfa_painted-768x527.jpeg 768w, https://cdn.help.prusa3d.com/wp-content/uploads/73fa58fb081ffbfa_painted-1536x1053.jpeg 1536w" alt="" width="600" height="411" loading="lazy" /></p>
<h4>Large adjustments</h4>
<p>If a slight adjustment is not sufficient you must adjust it at the belt holder. There are two main types of the Y-axis belt holder, one adjustable and one fixed. The adjustable belt holder was introduced in the first quarter of 2019, with the S-upgrade for the Original Prusa MK3, and is also featured on the Original Prusa MK4. Adjustments for this are explained in '<strong>Method 1</strong>'. For an earlier Original Prusa MK3, follow '<strong>Method 2</strong>', for the fixed belt holder.</p>
<h4>Method 1 - Adjustable belt holder</h4>
<div class="tip-callout">The Original Prusa MK4/S has a different design than in the pictures, but the procedure is the same. </div>
<ol>
<li>Unplug the printer and lay it over on the side of the PSU.</li>
<li>Below the bed carriage, you will find the belt holder. Loosen the right screw by turning it <strong>counterclockwise</strong> (<span style="color: #e67e23;"><strong>orange circle</strong></span> left picture).</li>
<li>Turn the screw going through the two halves of the belt holder (<span style="color: #b96ad9;"><strong>purple arrow</strong></span> right picture). Turn <strong>clockwise</strong> to tighten the belt, moving the two halves together (<span style="color: #236fa1;"><strong>blue arrows</strong></span>).</li>
<li>When at the correct tension, secure the right half of the belt holder again by turning the screw from step 2 clockwise (<span style="color: #e67e23;"><strong>orange circle</strong></span> left picture).</li>
</ol>
<table style="border-collapse: collapse; width: 100%;" border="0">
<tbody>
<tr>
<td style="width: 48.8106%;"><img decoding="async" src="https://cdn.help.prusa3d.com/wp-content/uploads/b0f4fab2c260d687_painted.jpeg" sizes="100vw" srcset="https://cdn.help.prusa3d.com/wp-content/uploads/b0f4fab2c260d687_painted-533x400.jpeg 533w, https://cdn.help.prusa3d.com/wp-content/uploads/b0f4fab2c260d687_painted-800x600.jpeg 800w, https://cdn.help.prusa3d.com/wp-content/uploads/b0f4fab2c260d687_painted-300x225.jpeg 300w, https://cdn.help.prusa3d.com/wp-content/uploads/b0f4fab2c260d687_painted-768x576.jpeg 768w, https://cdn.help.prusa3d.com/wp-content/uploads/b0f4fab2c260d687_painted-1536x1152.jpeg 1536w" alt="" width="400" height="300" loading="lazy" /></td>
<td style="width: 48.8106%;"><img decoding="async" src="https://cdn.help.prusa3d.com/wp-content/uploads/fdec3d592f278afe_painted.jpeg" sizes="100vw" srcset="https://cdn.help.prusa3d.com/wp-content/uploads/fdec3d592f278afe_painted-533x400.jpeg 533w, https://cdn.help.prusa3d.com/wp-content/uploads/fdec3d592f278afe_painted-800x600.jpeg 800w, https://cdn.help.prusa3d.com/wp-content/uploads/fdec3d592f278afe_painted-300x225.jpeg 300w, https://cdn.help.prusa3d.com/wp-content/uploads/fdec3d592f278afe_painted-768x576.jpeg 768w, https://cdn.help.prusa3d.com/wp-content/uploads/fdec3d592f278afe_painted-1536x1152.jpeg 1536w" alt="" width="400" height="300" loading="lazy" /></td>
</tr>
</tbody>
</table>
<h4>Method 2 - Fixed belt holder</h4>
<ol>
<li>Unplug the printer and lay it over on the side of the PSU.</li>
<li>Detach the belt-idler in order to easier manipulate the belt (<strong><span style="color: #b96ad9;">purple arrows</span></strong>). <em>Detaching the idler completely may not be necessary, but will make it easier to adjust the belt in the next step.</em></li>
</ol>
<p><img decoding="async" style="display: block; margin-left: auto; margin-right: auto;" src="https://cdn.help.prusa3d.com/wp-content/uploads/e5390e0a76daf6dc_painted.jpeg" sizes="100vw" srcset="https://cdn.help.prusa3d.com/wp-content/uploads/e5390e0a76daf6dc_painted-533x400.jpeg 533w, https://cdn.help.prusa3d.com/wp-content/uploads/e5390e0a76daf6dc_painted-800x600.jpeg 800w, https://cdn.help.prusa3d.com/wp-content/uploads/e5390e0a76daf6dc_painted-300x225.jpeg 300w, https://cdn.help.prusa3d.com/wp-content/uploads/e5390e0a76daf6dc_painted-768x576.jpeg 768w, https://cdn.help.prusa3d.com/wp-content/uploads/e5390e0a76daf6dc_painted-1536x1152.jpeg 1536w" alt="" width="600" height="450" loading="lazy" /></p>
<ol start="3">
<li style="counter-increment: li 2;">Set a mark on the belt so you know how much you are moving it. Now take out the belt of the top slot, and move it in 1-2 teeth (<strong><span style="color: #236fa1;">blue arrow</span></strong>) before pushing it back into the slot (<strong><span style="color: #2dc26b;">green arrows</span></strong>).</li>
</ol>
<p style="text-align: center;"><img decoding="async" style="display: block; margin-left: auto; margin-right: auto;" src="https://cdn.help.prusa3d.com/wp-content/uploads/10714ac443ad0a9c_painted.jpeg" sizes="100vw" srcset="https://cdn.help.prusa3d.com/wp-content/uploads/10714ac443ad0a9c_painted-533x400.jpeg 533w, https://cdn.help.prusa3d.com/wp-content/uploads/10714ac443ad0a9c_painted-800x600.jpeg 800w, https://cdn.help.prusa3d.com/wp-content/uploads/10714ac443ad0a9c_painted-300x225.jpeg 300w, https://cdn.help.prusa3d.com/wp-content/uploads/10714ac443ad0a9c_painted-768x576.jpeg 768w, https://cdn.help.prusa3d.com/wp-content/uploads/10714ac443ad0a9c_painted-1536x1152.jpeg 1536w" alt="" width="600" height="450" loading="lazy" /><em>Your belt mount may look slightly different, being another iteration, but the procedure remains the same.</em></p>
<ol start="4">
<li style="counter-increment: li 3;">Re-attach the belt-idler with its two M3x10 screws through the frame (<strong><span style="color: #b96ad9;">purple arrow</span></strong>). Leave a gap with the frame, for slight adjustments (<strong>blue arrows</strong>). </li>
</ol>
<p><img decoding="async" style="display: block; margin-left: auto; margin-right: auto;" src="https://cdn.help.prusa3d.com/wp-content/uploads/73fa58fb081ffbfa_painted.jpeg" sizes="100vw" srcset="https://cdn.help.prusa3d.com/wp-content/uploads/73fa58fb081ffbfa_painted-583x400.jpeg 583w, https://cdn.help.prusa3d.com/wp-content/uploads/73fa58fb081ffbfa_painted-800x549.jpeg 800w, https://cdn.help.prusa3d.com/wp-content/uploads/73fa58fb081ffbfa_painted-300x206.jpeg 300w, https://cdn.help.prusa3d.com/wp-content/uploads/73fa58fb081ffbfa_painted-768x527.jpeg 768w, https://cdn.help.prusa3d.com/wp-content/uploads/73fa58fb081ffbfa_painted-1536x1053.jpeg 1536w" alt="" width="600" height="411" loading="lazy" /></p>

Adjusting belt tension (MK4/S, MK3.9/S, MK3.5/S, MK3/S/+)

<p>On the Original Prusa MK4/S, MK3.9/S, MK3.5, and XL, the firmware is flashed by using a USB flash drive.</p>
<ol>
<li>Download the latest firmware for your printer and extract it (zip file) on your computer
<ul>
<li><a href="https://help.prusa3d.com/tag/mk4s">Original Prusa MK4S</a></li>
<li><a href="https://help.prusa3d.com/tag/mk4">Original Prusa MK4</a></li>
<li><a href="https://help.prusa3d.com/tag/mk3-9s">Original Prusa MK3.9S</a></li>
<li><a href="https://help.prusa3d.com/tag/mk3-9">Original Prusa MK3.9</a></li>
<li><a href="https://help.prusa3d.com/tag/mk3-5s">Original Prusa MK3.5S</a></li>
<li><a href="https://help.prusa3d.com/tag/mk3-5">Original Prusa MK3.5</a></li>
<li><a href="https://help.prusa3d.com/tag/xl">Original Prusa XL</a></li>
</ul>
</li>
<li>Make sure the USB flash drive doesn't contain any previous firmware (.bbf file)</li>
<li>Copy the new .bbf file to the root directory of a USB flash drive (Not within a folder).</li>
<li>Insert the USB flash drive and push the reset button<strong>.</strong> The bootloader will automatically compare the installed version with the one on the drive and, if newer, will automatically offer you to flash it.</li>
<li>Confirm the update by selecting the "FLASH" button and pressing the knob. </li>
</ol>
<p> </p>
<div><img decoding="async" style="display: block; margin-left: auto; margin-right: auto;" src="https://cdn.help.prusa3d.com/wp-content/uploads/2023/05/035427dd374ce9f494d89568ff3e72ac.jpg" sizes="(min-width: 1024px) 820px, 100vw" srcset="Flashing firmware (MK4)" alt="" width="700" height="276" loading="lazy" /></div>
<h3>Alternative method - older firmware release (firmware downgrade)</h3>
<p>It is not possible to flash to the same, or an older version of the firmware release, using the method above. To flash an older firmware the procedure is as follows:</p>
<ol>
<li>Push the reset button, immediately followed by clicking the selector knob.</li>
<li>On the new screen, confirm the update by selecting the "FLASH" button and pressing the knob. </li>
</ol>
<div class="warning-callout">If it repeatedly only boots the printer and gives you the home screen try to <a href="http://help.prusa3d.com/article/sd-cards-and-usb-drives_112291">format your USB flash-drive</a> or try a different one. <strong>Even if the flash drive works with G-Codes and printing, it may not work for flashing the firmware.</strong></div>


How to update firmware (MK4/S, MK3.9/S, MK3.5/S, XL)

<p>As there are ways of remotely transferring files and starting prints, an SD card or USB flash drive is the most common and reliable way to get your files to your machine. Though common and convenient, flash memory is not the most reliable in itself and your storage can be corrupted or fill up without any obvious signs. Therefore, we have put together a small guide on how to maintain, format, and purchase memory for your Original Prusa printer.</p>
<h3>Make sure your SD card is not locked!</h3>
<p>The SD card has a latch on the side. Before using your SD card, make sure that the latch is not set to the Locked position. In case it is locked, you will not be able to save files on the card, and the printer will not be able to open the SD card.</p>
<p><img decoding="async" style="max-height: 350px; display: block; margin-left: auto; margin-right: auto;" src="https://cdn.help.prusa3d.com/wp-content/uploads/SD-cards-and-USB-flash-drives-01.jpg" sizes="100vw" srcset="https://cdn.help.prusa3d.com/wp-content/uploads/SD-cards-and-USB-flash-drives-01-300x293.jpg 300w, https://cdn.help.prusa3d.com/wp-content/uploads/SD-cards-and-USB-flash-drives-01-410x400.jpg 410w" data-hd-height="350px" data-hd-align="center"></p>
<h3>Storage over 32 GB</h3>
<p>There is no upper size limit on compatible storage media, but <strong>the built-in Windows formatting tool does not support formatting storage media from a size of 32 GB or more to FAT32.</strong> It will only provide the option for exFAT, which is currently not supported by our printers. There are similar limitations under various versions of Apple's OSx, where a third-party application must be used to format it correctly.</p>
<p>To format such a drive you need a third-party application, like Rufus, FAT32 format, or EaseUS Partition Master. <strong>Be careful when using such programs</strong> so you do not <strong>accidentally format the wrong storage media</strong>, like your hard drive. However, 8-16 GB is more than enough for most use cases, as a G-code file rarely exceeds 100 MB.</p>
<h3>How do I format the USB drive/SD card?</h3>
<p>If your SD card or USB drive is full or if you can't read the content of the drive, but the drive is recognized by windows, most often all you need to do is to format the drive.</p>
<div class="note-callout">If your USB drive or SD card does not even show up in your computer file explorer it is probably corrupted beyond repair, or at least beyond the scale of this article. If you get an error like the one in the picture below and it does not show up anywhere, off to google you go, but you might have to consider this card/USB drive lost and get a new one.</div>
<p><img decoding="async" loading="lazy" style="display: block; margin-left: auto; margin-right: auto;" src="https://cdn.help.prusa3d.com/wp-content/uploads/SD-cards-and-USB-flash-drives-02V3.jpg" sizes="100vw" srcset="https://cdn.help.prusa3d.com/wp-content/uploads/SD-cards-and-USB-flash-drives-02V3-600x238.jpg 600w, https://cdn.help.prusa3d.com/wp-content/uploads/SD-cards-and-USB-flash-drives-02V3-800x317.jpg 800w, https://cdn.help.prusa3d.com/wp-content/uploads/SD-cards-and-USB-flash-drives-02V3-300x119.jpg 300w, https://cdn.help.prusa3d.com/wp-content/uploads/SD-cards-and-USB-flash-drives-02V3-768x304.jpg 768w" alt="" width="631" height="250"></p>
<h3>How to format on Windows</h3>
<p>On Windows, this is very simple. Locate your USB drive or SD card in my computer, right-click, and choose format.</p>
<p><img decoding="async" style="max-height: 350px; display: block; margin-left: auto; margin-right: auto;" src="https://cdn.help.prusa3d.com/wp-content/uploads/SD-cards-and-USB-flash-drives-03.png" sizes="100vw" srcset="https://cdn.help.prusa3d.com/wp-content/uploads/SD-cards-and-USB-flash-drives-03-300x288.png 300w, https://cdn.help.prusa3d.com/wp-content/uploads/SD-cards-and-USB-flash-drives-03-417x400.png 417w, https://cdn.help.prusa3d.com/wp-content/uploads/SD-cards-and-USB-flash-drives-03-768x737.png 768w, https://cdn.help.prusa3d.com/wp-content/uploads/SD-cards-and-USB-flash-drives-03-625x600.png 625w" data-hd-height="350px" data-hd-align="center"></p>
<p>A new small window will pop up. Most of the time you can simply leave everything to default, but the most important thing is that the <strong>File System is set to FAT32.</strong> This and the Volume Label (Name of the drive) is the only thing you want to touch here. Click Start and your drive will be formatted in a matter of seconds.</p>
<div class="warning-callout">Formatting any drive will delete all the content of the drive! Back up your stuff!</div>
<p><img decoding="async" style="max-height: 300px; display: block; margin-left: auto; margin-right: auto;" title="https://cdn.help.prusa3d.com/wp-content/uploads/SD-cards-and-USB-flash-drives-04-166x300.png 166w, https://cdn.help.prusa3d.com/wp-content/uploads/SD-cards-and-USB-flash-drives-04-222x400.png 222w" src="https://cdn.help.prusa3d.com/wp-content/uploads/SD-cards-and-USB-flash-drives-04.png" data-hd-height="300px" data-hd-align="center"></p>
<div class="note-callout">If the USB stick will not work even after this procedure, it is either broken or its "partitioning scheme" is set as GPT, which is incorrect. <strong>It must be set as MBR (Master Boot Record).</strong> For how to change this, please see <a href="https://docs.microsoft.com/en-us/windows-server/storage/disk-management/change-a-gpt-disk-into-an-mbr-disk">Microsoft's official documentation</a>.</div>
<h3>How to format on Mac</h3>
<p>On Mac, it is a few more steps, but still very accessible. Again, you want to choose <strong>FAT32 as your file system</strong>, but you also have the option of changing the "partitioning scheme", which <strong>should always be MBR (Master Boot Record).</strong></p>
<div class="warning-callout">This process deletes all content from the drive.</div>
<ol>
<li>Plug the USB drive or SD card into your Mac.</li>
<li>Go to <em>Applications -&gt; Utilities</em> and launch <em>Disk Utility.</em></li>
<li>Click on the icon in the top-left (<span style="color: #2dc26b;">green arrow</span>) and select "Show All Devices" from the drop-down menu.</li>
</ol>
<p><img decoding="async" loading="lazy" style="display: block; margin-left: auto; margin-right: auto;" src="https://cdn.help.prusa3d.com/wp-content/uploads/2021/10/b49c3bac01f2fd71_painted.png" sizes="(min-width: 1024px) 820px, 100vw" srcset="https://cdn.help.prusa3d.com/wp-content/uploads/2021/10/b49c3bac01f2fd71_painted-600x271.png 600w, https://cdn.help.prusa3d.com/wp-content/uploads/2021/10/b49c3bac01f2fd71_painted-800x361.png 800w, https://cdn.help.prusa3d.com/wp-content/uploads/2021/10/b49c3bac01f2fd71_painted-300x135.png 300w, https://cdn.help.prusa3d.com/wp-content/uploads/2021/10/b49c3bac01f2fd71_painted-768x347.png 768w, https://cdn.help.prusa3d.com/wp-content/uploads/2021/10/b49c3bac01f2fd71_painted-1536x693.png 1536w, https://cdn.help.prusa3d.com/wp-content/uploads/2021/10/b49c3bac01f2fd71_painted.png 1600w" alt="" width="500" height="226"></p>
<p style="text-align: center;"><em>macOS Big Sur 11.6</em></p>
<ol start="4">
<li>Right-click on the USB drive/SD card in the sidebar under "External". <em>Select the top entry for your drive, not a partition located below.</em></li>
<li>Select Erase in the Disk Utility-toolbar (<span style="color: #b96ad9;">purple arrow</span>).</li>
</ol>
<p><img decoding="async" loading="lazy" style="display: block; margin-left: auto; margin-right: auto;" src="https://cdn.help.prusa3d.com/wp-content/uploads/2021/10/b04f0e7375dfbc17_painted.png" sizes="(min-width: 1024px) 820px, 100vw" srcset="https://cdn.help.prusa3d.com/wp-content/uploads/2021/10/b04f0e7375dfbc17_painted-600x271.png 600w, https://cdn.help.prusa3d.com/wp-content/uploads/2021/10/b04f0e7375dfbc17_painted-800x361.png 800w, https://cdn.help.prusa3d.com/wp-content/uploads/2021/10/b04f0e7375dfbc17_painted-300x135.png 300w, https://cdn.help.prusa3d.com/wp-content/uploads/2021/10/b04f0e7375dfbc17_painted-768x347.png 768w, https://cdn.help.prusa3d.com/wp-content/uploads/2021/10/b04f0e7375dfbc17_painted-1536x693.png 1536w, https://cdn.help.prusa3d.com/wp-content/uploads/2021/10/b04f0e7375dfbc17_painted.png 1600w" alt="" width="500" height="226"></p>
<p style="text-align: center;"><em>macOS Big Sur 11.6</em></p>
<ol start="6">
<li>Enter a name for the formatted disk.</li>
<li>Click on the Format menu and choose MS-DOS (FAT).</li>
<li>Make sure the Scheme is set to "Master Boot Record".</li>
</ol>
<p><img decoding="async" loading="lazy" style="display: block; margin-left: auto; margin-right: auto;" src="https://cdn.help.prusa3d.com/wp-content/uploads/2021/10/snmek-obrazovky-2021-10-07-v8-32-01.png" sizes="(min-width: 1024px) 820px, 100vw" srcset="https://cdn.help.prusa3d.com/wp-content/uploads/2021/10/snmek-obrazovky-2021-10-07-v8-32-01-600x301.png 600w, https://cdn.help.prusa3d.com/wp-content/uploads/2021/10/snmek-obrazovky-2021-10-07-v8-32-01-800x401.png 800w, https://cdn.help.prusa3d.com/wp-content/uploads/2021/10/snmek-obrazovky-2021-10-07-v8-32-01-300x150.png 300w, https://cdn.help.prusa3d.com/wp-content/uploads/2021/10/snmek-obrazovky-2021-10-07-v8-32-01-768x385.png 768w, https://cdn.help.prusa3d.com/wp-content/uploads/2021/10/snmek-obrazovky-2021-10-07-v8-32-01-1536x771.png 1536w, https://cdn.help.prusa3d.com/wp-content/uploads/2021/10/snmek-obrazovky-2021-10-07-v8-32-01-2048x1027.png 2048w, https://cdn.help.prusa3d.com/wp-content/uploads/2021/10/snmek-obrazovky-2021-10-07-v8-32-01.png 1600w" alt="" width="500" height="251"></p>
<p style="text-align: center;"><em>macOS Big Sur 11.6</em></p>
<ol start="9">
<li>Click Erase.</li>
<li>Your USB drive will now be erased and re-formatted correctly.</li>
</ol>
<div class="tip-callout">If your SD card is not detected by the printer at all, be sure to check out <a href="http://help.prusa3d.com/article/sd-card-not-working_2095">SD card not working</a> for further information.</div>

SD cards and USB drives

<p>The  'cold pull' technique allows you to clean your printer’s nozzle and hotend from any material that may be stuck or burnt inside. You can also use it to clean your hotend during your usual maintenance routine. Starting from firmware 6.0.0 on MK4/S and MK3.9/S, and from firmware 6.1.3 on XL, the printer will do the process automatically. </p>
<div class="warning-callout">If you use <strong>Nozzle X</strong> (requires Nextruder V6 Nozzle Adapter), <strong>do not</strong> use the cold-pull method, only cleaning filament.</div>
<p>The cold pull should be done if your nozzle is only partially clogged, and some filament is still being extruded. If the nozzle is completely clogged, please check the clogged hotend article for <a href="http://help.prusa3d.com/article/clogged-hotend-mk4_411823">MK4/MK3.9</a>, or for <a href="http://help.prusa3d.com/article/clogged-hotend-xl_401294">XL</a>.</p>
<p>Our testing has found that PLA works best for a cold pull, as other filaments do not retain the tip as PLA does and they will either tear or melt too much. However, there are filaments specifically made for cleaning hotends.</p>
<h3>Automatic cold pull </h3>
<p>Have at least 30cm of PLA available when making this procedure. On multi-tool XL, pick the desired tool. Navigate to <em>LCD Menu -&gt; Control -&gt; Pick/Park Tool -&gt; Pick Tool #</em>. </p>
<p>Then, navigate to <em>LCD Menu -&gt; Control -&gt; Cold Pull</em>. </p>
<p>On MK4/S and MK3.9, you will see the options: unload the current filament (recommended in case you have any filament other than PLA loaded), Load PLA filament, and continue with the loaded filament (only use it if the filament loaded is PLA).</p>
<p style="text-align: center;"><img decoding="async" style="display: block; margin-left: auto; margin-right: auto;" src="https://cdn.help.prusa3d.com/wp-content/uploads/2024/04/02698ca5c3dc39344b07e95f053ab7c5.jpg" alt="" width="400" height="267" loading="lazy" /><em>Display screenshot for MK4/S, MK3.9/S</em></p>
<p>On XL, it is necessary to load the filament directly into the Nextruder. For this reason, before you continue, unload the filament. Then press down the blue part on the fitting and pull the PTFE tube from the tool head. After this, load the PLA filament directly into the Nextruder. </p>
<table style="border-collapse: collapse; width: 100%; border-style: none;" border="1">
<tbody>
<tr>
<td style="width: 48.8562%;"><img decoding="async" src="https://cdn.help.prusa3d.com/wp-content/uploads/2024/09/f28dbe21e86e44c93afe691f3eef0c08.jpg" alt="" width="395" height="263" loading="lazy" /></td>
<td style="width: 48.8562%;"><img decoding="async" src="https://cdn.help.prusa3d.com/wp-content/uploads/2024/09/e0fb3a4c5e8e2d4f11132ef268f9d0fb.jpg" sizes="(min-width: 1024px) 820px, 100vw" srcset="Cold pull (MK4, MK3.9, XL) #13702" alt="" width="395" height="263" loading="lazy" /></td>
</tr>
</tbody>
</table>
<div style="text-align: center;"><em>Screenshots taken on the Original Prusa XL</em></div>
<p>If the nozzle is heated, the printer will wait until it cools to 36 ºC. Then it will heat the printer to 80 ºC. After that, the printer will unload the filament automatically at that temperature.</p>
<table style="border-collapse: collapse; width: 100%;" border="0">
<tbody>
<tr>
<td style="width: 48.8358%;"><img decoding="async" src="https://cdn.help.prusa3d.com/wp-content/uploads/2024/04/e80788765382bc70f181e67f8b120388.jpg" sizes="(min-width: 1024px) 820px, 100vw" srcset="Cold pull (MK3.9, MK4) #13702" alt="" width="400" height="267" loading="lazy" /></td>
<td style="width: 48.8358%;"><img decoding="async" src="https://cdn.help.prusa3d.com/wp-content/uploads/2024/04/dc3aa0f7294933f18437bd2ecb20b3c3.jpg" sizes="(min-width: 1024px) 820px, 100vw" srcset="Cold pull (MK3.9, MK4) #13702" alt="" width="400" height="267" loading="lazy" /></td>
</tr>
</tbody>
</table>
<p>To finalize the procedure, remove the filament by hand, pulling it upwards. There might be a slight resistance, if the filament is stuck, open the idler lever. </p>
<p style="text-align: center;"><img decoding="async" src="https://cdn.help.prusa3d.com/wp-content/uploads/2024/09/440a42641852f2eebe67ec6bdc2e8f52.jpg" sizes="(min-width: 1024px) 820px, 100vw" srcset="Cold pull (MK4, MK3.9, XL) #13702" alt="" width="400" height="267" loading="lazy" /></p>
<h3>Manual Cold pull (XL, MK4/MK3.9 pre-firmware 5.1.3)</h3>
<h4>Preliminary steps (XL)</h4>
<ul>
<li>On multi-tool XL, pick the desired tool. Navigate to <em>LCD Menu -&gt; Control -&gt; Pick/Park Tool -&gt; Pick Tool #</em>. </li>
<li>Temporarily unscrew the fitting above the Nextruder. </li>
</ul>
<h4>Procedure (XL pre-firmware 6.1.3, MK4/MK3.9 pre-firmware 5.1.3)</h4>
<ol>
<li>Load a piece of PLA filament in the extruder, inserting it from above the extruder. The printer will prompt a material selection: select PLA and complete the loading procedure. </li>
<li>Open the Idler Swivel.<br /><img decoding="async" style="display: block; margin-left: auto; margin-right: auto;" src="https://cdn.help.prusa3d.com/wp-content/uploads/2023/03/XL_Extruder_Open2.jpg" sizes="(min-width: 1024px) 820px, 100vw" srcset="Cold pull (MK3.9, MK4) #13702" alt="" width="500" height="375" loading="lazy" /></li>
<li>Go to <em>LCD Menu -&gt; Control -&gt; Temperature -&gt; Nozzle Temperature</em> and set the temperature to 270 °C.</li>
<li>Once it has reached 270 °C push the PLA filament in until it starts pouring out of the nozzle.</li>
<li>Stop heating by pressing Cooldown in the <em>LCD Menu -&gt; Control -&gt; Temperature -&gt; Cooldown</em>, or by pressing the reset button. </li>
<li>Continue manually pushing the filament down until the temperature is too low for it to melt and come out (around 170 °C for PLA). The nozzle has to be filled for the cold pull to be successful.</li>
<li>Pick away any extruded material from the nozzle so nothing is obstructing the pull later on.</li>
<li>Wait for the temperature to reach 100 °C. As soon as it reaches 100 °C, grab the filament with pliers and pull it slowly but steadily out of the extruder. Make sure to pull straight upwards, not sideways, or the filament can break inside. Hold the extruder with your other hand.</li>
<li>Don't stop until the filament is completely pulled out from the extruder.</li>
<li>Close the Idler and the Idler Swivel. </li>
</ol>
<h3>Results</h3>
<p>On the tip of the filament that has been pulled out, you may see remnants of the previous material(s) you have been using or some burnt dirt that has settled in the nozzle (left picture). You might want to repeat this procedure several times until the filament comes out clean.</p>
<p>The right picture shows what a clean cold-pulled filament should look like. It is important to have the imprint of the nozzle on it, this way you are sure the nozzle was filled and nothing was left inside. Also, the color is not mixed with the one you have been using previously or has dark marks on it.</p>
<table style="border-collapse: collapse; width: 100%;" border="0">
<tbody>
<tr>
<td style="width: 48.805%;"><img decoding="async" style="display: block; margin-left: auto; margin-right: auto;" src="https://cdn.help.prusa3d.com/wp-content/uploads/dirty-cold-pull.jpg" sizes="100vw" srcset="https://cdn.help.prusa3d.com/wp-content/uploads/dirty-cold-pull-300x214.jpg 300w, https://cdn.help.prusa3d.com/wp-content/uploads/dirty-cold-pull-561x400.jpg 561w, https://cdn.help.prusa3d.com/wp-content/uploads/dirty-cold-pull-768x548.jpg 768w, https://cdn.help.prusa3d.com/wp-content/uploads/dirty-cold-pull-800x571.jpg 800w" alt="dirty cold pull" width="399" height="285" loading="lazy" /></td>
<td style="width: 48.9057%;"><img decoding="async" style="display: block; margin-left: auto; margin-right: auto;" src="https://cdn.help.prusa3d.com/wp-content/uploads/clean-cold-pull.jpg" sizes="100vw" srcset="https://cdn.help.prusa3d.com/wp-content/uploads/clean-cold-pull-300x203.jpg 300w, https://cdn.help.prusa3d.com/wp-content/uploads/clean-cold-pull-591x400.jpg 591w, https://cdn.help.prusa3d.com/wp-content/uploads/clean-cold-pull-768x520.jpg 768w, https://cdn.help.prusa3d.com/wp-content/uploads/clean-cold-pull-800x542.jpg 800w" alt="clean cold pull" width="399" height="270" loading="lazy" /></td>
</tr>
</tbody>
</table>


Cold pull (MK4/S, MK3.9/S, XL) #13702 #17702

<p>It is recommended to take some time to maintain your Original Prusa MK4/S and MK3.9/S regularly. This should be done even if the printer is working perfectly. </p>
<h3>Useful tools</h3>
<p>Besides the usual tools, such as Allen keys, needle-nose pliers, and IPA (Isopropyl Alcohol) + paper towels, you might need:</p>
<ul>
<li><strong>Compressed air</strong>: also known as canned air. Be sure to not hold it upside down while spraying - otherwise, you could damage any electronic components while trying to clean them.</li>
<li><strong>Brush</strong>: a small brass brush is useful for cleaning the heaterblock. If you don't have a brass brush any brush with hard bristles will do the job.</li>
<li><strong>Prusa Lubricant</strong>: used for lubricating the smooth rods and linear bearings. </li>
</ul>
<div class="warning-callout"><strong>Do not apply lubricant on the trapezoid nuts or the threaded lead screws of the Z-axis!</strong></div>
<h3>Frequent maintenance </h3>
<p>The following points should be checked before every print. </p>
<h4>Keeping the printer clean </h4>
<p>After several hours of printing, various kinds of debris may start to accumulate around the printer parts or under the heatbed - pieces of filament, dust, scraps, broken supports, etc. Always make sure that the parts of the printer are clean. You can use a brush, a small broom, or a vacuum to remove debris. </p>
<h4>Hotend cleaning</h4>
<div class="warning-callout"><strong>CAUTION</strong>: Heated parts can cause severe burns!</div>
<p>It is fundamental for the hotend to be clean. Debris on the nozzle or heaterblock can cause printer failures, for example with the residue falling onto the printed model while the print is in progress.</p>
<p>To clean the nozzle and heaterblock, heat the nozzle for three to five minutes at 250 °C, as the remains of the filament must be warmed up slightly so that they can be removed more easily.</p>
<p>Use a small brass brush to clear away any old plastic stuck on the nozzle and heaterblock.</p>
<p><strong>Avoid contact of the brush with the hotend cables, as this could cause a short circuit.</strong></p>
<p><strong>Caution: the printer is still at a hot temperature! Wait until the hot parts are cooled down to ambient temperature. It takes approximately 10 minutes. Do not touch it! Always check the values on the display.</strong></p>
<p><img decoding="async" style="display: block; margin-left: auto; margin-right: auto;" src="https://cdn.help.prusa3d.com/wp-content/uploads/2024/04/fd1ade6ac6057ce415a9e4ba0ec90244.jpg" alt="" width="500" height="375" loading="lazy" /></p>
<h4>Flexible steel sheet</h4>
<div class="warning-callout">Acetone should be used sparingly for cleaning, and only be used on the Smooth steel sheet! <strong>Never use acetone on the Textured or Satin steel sheet</strong> as the surface will be permanently damaged. </p>
<p>Never clean the special <a href="https://help.prusa3d.com/article/special-pa-nylon-steel-sheet_341570"><strong>PA Nylon sheet</strong></a> with acetone, IPA (isopropyl alcohol), or other alcohol-based solvents (window cleaners, Windex, etc.)! This will damage the surface.</div>
<p>All flexible steel sheets should be cleaned regularly to ensure adhesion, but the exact methods and washing solutions can differ depending on your type of sheet.</p>
<p>You can find more information on how to take care of your flexible steel sheet <a href="http://help.prusa3d.com/article/flexible-steel-sheets-guidepost_2195">in this article</a>.</p>
<h3>Sporadic maintenance</h3>
<p>The following checks should be done every 200 hours of printing time. </p>
<h4>Axes check</h4>
<ul>
<li><strong>Smooth rods</strong>: scratches/grooves - take each rod between two/three fingers and move them slowly from one end of the rod to another, while rotating the fingers around the rod. If you notice any scratch, verify it with your fingernail. </li>
<li><strong>Smooth rods and Bearings</strong>: Clean the smooth rods with a clean paper towel, and lubricate them using a small amount of Prusa Lubricant. <br />Only in case you feel the axis is not running smoothly anymore even after recently cleaning and lubricating the smooth rods, bearings can be taken out, cleaned with alcohol, and greased on the inside, still using a small amount of Prusa Lubricant. </li>
<li><strong>Belt pulleys</strong>: any debris around the belt pulleys and belts should be immediately removed to ensure smooth operations. Also, check if the set screw of the belt pulley is firmly secured on the flat side of the motor shaft.</li>
<li><strong>Belts</strong>: Both of the belts should be tight enough to sound like a low bass note when plucked. </li>
</ul>
<h4>Fans</h4>
<p>The RPM (revolutions per minute) of both fans is constantly measured. This means that the printer will report an error if the fan suddenly slows down, for example, due to a piece of filament stuck in it.</p>
<p>In such a case, check and remove any dirt from the relevant fan. <strong>Do not try to bypass the RPM check, as this could damage the printer!</strong></p>
<p>Both fans should be checked and cleaned after every few hundred hours of printing. Dust can be removed with compressed air in a spray can, small plastic threads can be removed with tweezers. </p>
<div>
<div class="note-callout">Do not blow compressed air on the running fan.</div>
<h4>Nextruder</h4>
</div>
<div class="warning-callout">When accessing the extruder parts, avoid opening the gearbox, unless our official <a href="http://help.prusa3d.com/article/customer-support_2287">technical support</a> asks for it. In case you need to open the gearbox, make sure that you have the <a href="https://www.printables.com/model/451501-mk4-printable-parts/files">Assembly Adapter</a> printed so it can be re-assembled correctly.</div>
<p>The primary gear and the bearings attached to the Idler Shaft in the extruder do not need any lubricant. Over time, a deposit of filament debris can form in the grooves of the primary gear, which then causes insufficient filament extrusion. Access the extruder by lifting the Idler Nut, and then moving the Idler Shaft. You can blow away the dirt with compressed air, or use a brass brush or an ordinary toothpick. Use the access hole on the side of the extruder. </p>
<p><img decoding="async" style="display: block; margin-left: auto; margin-right: auto;" src="https://cdn.help.prusa3d.com/wp-content/uploads/2023/03/XL_Extruder_Open2.jpg" sizes="(min-width: 1024px) 820px, 100vw" srcset="Regular printer maintenance (MK4)" alt="" width="600" height="450" loading="lazy" /></p>
<h3>Annual maintenance</h3>
<h4>Electronics</h4>
<div class="warning-callout">Before touching the electrical connections, please make sure that the printer is off, and unplugged from the main power source.</div>
<p>It is a good practice to check and optionally reconnect the electrical connectors on the xBuddy board, Loveboard, heatbed, PSU, and xLCD every 600-800 hours of printing. </p>
<p>In particular, ensure that the screw-attached connectors are fully tightened, and the Molex-attached connectors properly connected. </p>
<p>CAUTION: for Molex-attached connectors, it is necessary to press the latch before disconnecting. Otherwise, the connector may get damaged. </p>


Regular printer maintenance (MK4/S, MK3.9/S)

<p>Before you start printing, you should know that various materials have different adhesions on various surfaces. It is crucial to pick the right steel sheet for your printer and prepare its surface properly. This article is about the most common types of print surfaces and how to prepare them for printing.</p>
<div class="tip-callout">To kick it off with a quick (and most common) example: PETG filament has great adhesion to a clean, degreased, smooth PEI sheet, making it extremely hard to remove. Removing the print often leads to peeling off the PEI surface and irreversible damage to the sheet. This is why we recommend using another type of steel sheet or adding PVA glue as a separation layer on the print surface.</div>
<h3><img decoding="async" src="https://cdn.help.prusa3d.com/wp-content/uploads/steelsheet.jpg" alt="" width="1024" height="703" loading="lazy" /></h3>
<p><em>Steel sheet damaged by a PETG print</em></p>
<h3>Choosing the right print sheet</h3>
<p>We offer 4 types of spring steel sheets, each has a different surface finish that leaves not only a specific texture on your print but also supports a variety of materials that can be printed on it.</p>
<div class="note-callout"><a href="http://help.prusa3d.com/article/smooth-steel-sheet_196550">Here’s a guidepost</a> that provides the most information about the maintenance and properties of our three most common print sheets. Plus, <a href="http://help.prusa3d.com/article/special-pa-nylon-steel-sheet_341570">here’s an article</a> about our special PA Nylon steel sheet.</div>
<table style="border-collapse: collapse; width: 100%; height: 36px; margin-left: auto; margin-right: auto;" border="0">
<tbody>
<tr style="height: 18px;">
<td style="width: 32.2013%; height: 18px;"><img decoding="async" src="https://cdn.help.prusa3d.com/wp-content/uploads/2020/12/spring-steel-sheet-smooth-peiKB.jpg" sizes="100vw" srcset="https://cdn.help.prusa3d.com/wp-content/uploads/2020/12/spring-steel-sheet-smooth-peiKB-400x400.jpg 400w, https://cdn.help.prusa3d.com/wp-content/uploads/2020/12/spring-steel-sheet-smooth-peiKB-600x600.jpg 600w, https://cdn.help.prusa3d.com/wp-content/uploads/2020/12/spring-steel-sheet-smooth-peiKB-300x300.jpg 300w, https://cdn.help.prusa3d.com/wp-content/uploads/2020/12/spring-steel-sheet-smooth-peiKB-768x768.jpg 768w" alt="" width="266" height="266" loading="lazy" /></td>
<td style="width: 32.2013%; height: 18px;"><img decoding="async" src="https://cdn.help.prusa3d.com/wp-content/uploads/2020/12/powder-coated-spring-steel-sheetKB.jpg" sizes="100vw" srcset="https://cdn.help.prusa3d.com/wp-content/uploads/2020/12/powder-coated-spring-steel-sheetKB-400x400.jpg 400w, https://cdn.help.prusa3d.com/wp-content/uploads/2020/12/powder-coated-spring-steel-sheetKB-600x600.jpg 600w, https://cdn.help.prusa3d.com/wp-content/uploads/2020/12/powder-coated-spring-steel-sheetKB-300x300.jpg 300w, https://cdn.help.prusa3d.com/wp-content/uploads/2020/12/powder-coated-spring-steel-sheetKB-768x768.jpg 768w" alt="" width="266" height="266" loading="lazy" /></td>
<td style="width: 32.2013%; height: 18px;"><img decoding="async" src="https://cdn.help.prusa3d.com/wp-content/uploads/2020/12/double-sided-powder-coated-satin-spring-steel-sheetKB.jpg" sizes="100vw" srcset="https://cdn.help.prusa3d.com/wp-content/uploads/2020/12/double-sided-powder-coated-satin-spring-steel-sheetKB-400x400.jpg 400w, https://cdn.help.prusa3d.com/wp-content/uploads/2020/12/double-sided-powder-coated-satin-spring-steel-sheetKB-600x600.jpg 600w, https://cdn.help.prusa3d.com/wp-content/uploads/2020/12/double-sided-powder-coated-satin-spring-steel-sheetKB-300x300.jpg 300w, https://cdn.help.prusa3d.com/wp-content/uploads/2020/12/double-sided-powder-coated-satin-spring-steel-sheetKB-768x768.jpg 768w" alt="" width="266" height="266" loading="lazy" /></td>
</tr>
<tr style="height: 18px;">
<td style="width: 32.2013%; height: 18px; text-align: center;"><a href="http://help.prusa3d.com/article/smooth-steel-sheet_196550">Smooth sheet</a></td>
<td style="width: 32.2013%; height: 18px; text-align: center;"><a href="http://help.prusa3d.com/article/textured-steel-sheet_196534">Textured sheet</a></td>
<td style="width: 32.2013%; height: 18px; text-align: center;"><a href="http://help.prusa3d.com/article/satin-steel-sheet_196526">Satin sheet</a></td>
</tr>
<tr>
<td style="width: 32.2013%; text-align: center;"><img decoding="async" src="https://cdn.help.prusa3d.com/wp-content/uploads/2021/01/Smooth_underside2.jpg" sizes="100vw" srcset="https://cdn.help.prusa3d.com/wp-content/uploads/2021/01/Smooth_underside2-398x400.jpg 398w, https://cdn.help.prusa3d.com/wp-content/uploads/2021/01/Smooth_underside2-598x600.jpg 598w, https://cdn.help.prusa3d.com/wp-content/uploads/2021/01/Smooth_underside2-300x300.jpg 300w, https://cdn.help.prusa3d.com/wp-content/uploads/2021/01/Smooth_underside2-768x771.jpg 768w" alt="" width="266" height="267" loading="lazy" /></td>
<td style="width: 32.2013%; text-align: center;"><img decoding="async" src="https://cdn.help.prusa3d.com/wp-content/uploads/2021/01/TXT_underside2.jpg" sizes="100vw" srcset="https://cdn.help.prusa3d.com/wp-content/uploads/2021/01/TXT_underside2-398x400.jpg 398w, https://cdn.help.prusa3d.com/wp-content/uploads/2021/01/TXT_underside2-598x600.jpg 598w, https://cdn.help.prusa3d.com/wp-content/uploads/2021/01/TXT_underside2-300x300.jpg 300w, https://cdn.help.prusa3d.com/wp-content/uploads/2021/01/TXT_underside2-768x771.jpg 768w" alt="" width="266" height="267" loading="lazy" /></td>
<td style="width: 32.2013%; text-align: center;"><img decoding="async" src="https://cdn.help.prusa3d.com/wp-content/uploads/2021/01/satin_underside2.jpg" sizes="100vw" srcset="https://cdn.help.prusa3d.com/wp-content/uploads/2021/01/satin_underside2-398x400.jpg 398w, https://cdn.help.prusa3d.com/wp-content/uploads/2021/01/satin_underside2-598x600.jpg 598w, https://cdn.help.prusa3d.com/wp-content/uploads/2021/01/satin_underside2-300x300.jpg 300w, https://cdn.help.prusa3d.com/wp-content/uploads/2021/01/satin_underside2-768x771.jpg 768w" alt="" width="266" height="267" loading="lazy" /></td>
</tr>
</tbody>
</table>
<p>The best way to identify whether your sheet is suitable for the chosen material is by <a href="https://help.prusa3d.com/en/materials"><strong>checking our Material table</strong></a>. If there’s a green check mark matching the selected sheet and material, you can simply degrease the print surface and you’re good to go. If there’s an exclamation mark, a separation layer of some sort is needed (see below). <strong>Failing to use the separation layer may lead to damaging your sheet!</strong></p>
<p><img decoding="async" src="https://cdn.help.prusa3d.com/wp-content/uploads/2024/04/cbf6b670e81a869ca569857434eba048.jpg" sizes="(min-width: 1024px) 820px, 100vw" srcset="Print surface preparation" alt="" width="1950" height="656" loading="lazy" /></p>
<h3>Cleaning the print surface</h3>
<p>This is an easy, yet crucial step you should perform before (almost) every print. We already described this in the <a href="https://www.prusa3d.com/downloads/manual/prusa3d_manual_MK4_MK39_103_en.pdf">3D printing handbook</a> and several other places but here’s a quick reminder:</p>
<p>Grease stains (fingerprints, etc.) often cause poor surface adhesion and, eventually, a print failure. To degrease the print sheet, <strong>spray some isopropyl alcohol (90% or stronger)</strong> or denatured ethyl alcohol <strong>on the cold print surface</strong> and wipe it with an unscented paper towel. Do not use any products for skin care: they usually contain oils that ruin adhesion!</p>
<div class="note-callout">There are some more specific rules for long-term sheet maintenance and you should definitely learn these but it reaches beyond this article’s purpose. Don’t forget to go through <a href="http://help.prusa3d.com/article/smooth-steel-sheet_196550">the steel sheet guidepost</a>. Keep in mind that the <a href="http://help.prusa3d.com/article/special-pa-nylon-steel-sheet_341570">special PA Nylon sheet</a> has very different and highly specific rules for maintenance.</div>
<p>Alright, the print surface is clean, now the final checklist (<a href="https://help.prusa3d.com/en/materials">see the material table</a>):</p>
<ol>
<li><strong>Green check mark:</strong> Good to go!</li>
<li><strong>Yellow exclamation mark:</strong> Use a separation layer (see below).</li>
<li><strong>Red X:</strong> Do not print! The chosen material may damage your print sheet!</li>
</ol>
<h3>Using the most common separation layers</h3>
<p>You may find various separation (or adhesive) layer materials on the market, some of those even in our e-shop. Every material has its benefits, but describing every single one of them is beyond the scope of this article. If you check our material table, you’ll find out that it all comes down to two most common separation layers: <strong>PVA glue stick and PP tape.</strong></p>
<p><strong>PVA (paper) glue</strong> is usually sold in the form of sticks that make the application easier. <strong>Usually, only a thin layer of glue is enough.</strong> Spreading a thick layer may leave various unsightly traces, bumps, and artifacts that will be imprinted onto your 3D print’s surface. However, if you want to print a mechanical part, where good looks are not as important as functionality and reliability, making the layer slightly thicker won’t hurt. Also, the PVA glue melts at relatively low temperatures, so we suggest applying it on a cold surface to avoid making an extra thick layer.</p>
<div class="tip-callout">Tip: If you use the smooth print sheet, use the grid to guess the print size and position, then spread the glue only under the 3D print. You don’t need to spread the glue all over the whole sheet.</div>
<table style="border-collapse: collapse; width: 100%;" border="1">
<tbody>
<tr>
<td style="width: 32.2431%;"><img decoding="async" loading="lazy" src="https://cdn.help.prusa3d.com/wp-content/uploads/2024/04/d1bc8e9178fa20c7820b6c520c3777e0.jpg" sizes="(min-width: 1024px) 820px, 100vw" srcset="Print surface preparation" alt="" width="2506" height="1880" /></td>
<td style="width: 32.2431%;"><img decoding="async" loading="lazy" src="https://cdn.help.prusa3d.com/wp-content/uploads/2024/04/bb07c0b1d669e31b19f99420c5445ec0.jpg" sizes="(min-width: 1024px) 820px, 100vw" srcset="Print surface preparation" alt="" width="2506" height="1879" /></td>
<td style="width: 32.2457%;"><img decoding="async" loading="lazy" src="https://cdn.help.prusa3d.com/wp-content/uploads/2024/04/188aee6aea6ea114ef0b3a710169a3d1.jpg" sizes="(min-width: 1024px) 820px, 100vw" srcset="Print surface preparation" alt="" width="2506" height="1879" /></td>
</tr>
</tbody>
</table>
<p><em>PVA glue separation layer, 3D printed PETG parts, and marks left after removing the print. Note that these marks are normal as they are only on a PVA glue layer and not on the print sheet surface. These marks disappear with the glue after washing.</em></p>
<p>Finally, <strong>the PP tape.</strong> You will most likely not use it, since it’s recommended only for printing PP (Polypropylene), which is quite rare material to print. However, you may decide to use some other tape - kapton tape, for example. For the best adhesion, it is recommended to use in combination with a smooth sheet, no matter which tape you are going to choose. The tape may leave some glue residuals after removing it from the print sheet surface. Usually, these can be washed with IPA or with water and dishwasher soap, but again, double-check the <a href="http://help.prusa3d.com/article/smooth-steel-sheet_196550">steel sheet maintenance articles</a> before washing them.</p>
<div class="warning-callout">If you decide to use other separation materials or adhesives, don’t forget to check compatibility with our print sheets. For example, ABS juice should not be used in combination with textured or satin sheets.</div>
<h3>Removing the print</h3>
<p>One last thing: <strong>always remove the prints by removing and bending the sheet only after they are cooled down.</strong> The print will go off easily without the necessity of using various spatulas, knives, or anything else.</p>


Print surface preparation

<p>Sometimes it is necessary to reinstall an older version of the firmware. The normal flashing method only allows newer firmware versions to be flashed. To flash the same firmware, or an older one, follow the steps below.</p>
<ol>
<li>To find the older versions, go to the <a href="https://help.prusa3d.com/downloads">Downloads</a> page, select your printer, and click on <strong><span style="color: #e67e23;">Older versions</span></strong>.</li>
</ol>
<p><img decoding="async" style="display: block; margin-left: auto; margin-right: auto;" src="https://cdn.help.prusa3d.com/wp-content/uploads/2024/06/2d27f0914e1eb33fe468242efccbd072.jpg" sizes="(min-width: 1024px) 820px, 100vw" srcset="How to downgrade firmware (MK3.5/MK3.9/MK4/XL)" alt="" width="700" height="328" loading="lazy" /></p>
<ol start="2">
<li>Load the .bbf file directly into the root folder of the USB drive.</li>
<li>Insert the drive into the printer.</li>
<li>Push the reset button, and once the printer logo appears on the screen, press and hold the knob.</li>
<li>On the new screen, confirm the update by selecting the "FLASH" button and pressing the knob. </li>
</ol>
<p>If it repeatedly only boots the printer and gives you the home screen try to <a href="http://help.prusa3d.com/article/sd-cards-and-usb-drives_112291">format your USB flash-drive</a> or try a different one. Even if the flash drive works with G-Codes and printing, it may not work for flashing the firmware.</p>


How to downgrade firmware (MK4/S, MK3.9/S, MK3.5/S, XL)

<p>Replacing the Prusa Nozzle on your printer varies depending on the model of your printer. This article provides an overview of the different methods to replace the Prusa Nozzle, directing you to the appropriate guides for your specific printer model.</p>
<p><img decoding="async" style="display: block; margin-left: auto; margin-right: auto;" src="https://cdn.help.prusa3d.com/wp-content/uploads/2024/09/42b595784cf5f49217654d68c71c1b68.jpg" sizes="(min-width: 1024px) 820px, 100vw" srcset="Changing or replacing the Prusa Nozzle" alt="" width="50%" /></p>
<h3>Do I have the Prusa Nozzle?</h3>
<p>Every MK4S, MK3.9S, MK4, MK3.9 and XL that is shipped from our company comes with the Prusa Nozzle installed or included in the kit.</p>
<h3>Methods for replacing the Prusa Nozzle</h3>
<p>There are two different ways to replace the nozzle for each model. We have designed the <strong>Nozzle Replacement Tool</strong> that makes the process easier and quicker, <strong>but it requires printing the tool first</strong>. </p>
<div class="note-callout">All methods listed below are fully compatible with both Prusa Nozzle and Prusa Nozzle CHT diameters.</div>
<p>MK4S/MK3.9S</p>
<ul>
<li><a href="http://help.prusa3d.com/guide/how-to-replace-the-prusa-nozzle-mk4s-mk3-9s_734750">How to replace the Prusa Nozzle (MK4S/MK3.9S)</a></li>
<li><a href="https://www.printables.com/model/980297-mk4s-nozzle-replacement-tool">How to replace the Prusa Nozzle (MK4S/MK3.9S) using the MK4S Nozzle Replacement Tool</a> (instructions in the description on Printables.com)</li>
</ul>
<p>MK4/MK3.9</p>
<ul>
<li><a href="http://help.prusa3d.com/guide/how-to-replace-the-prusa-nozzle-mk4-mk3-9_421215">How to replace the Prusa Nozzle (MK4/MK3.9)</a></li>
<li><a href="https://www.printables.com/model/801656-mk4-nozzle-replacement-tool">How to replace the Prusa Nozzle (MK4/MK3.9) using the MK4 Nozzle Replacement Tool</a> (instructions in the description on Printables.com)</li>
</ul>
<p>XL Single-tool</p>
<ul>
<li><a href="http://help.prusa3d.com/guide/how-to-replace-the-prusa-nozzle-xl-single-tool_405846">How to replace the Prusa Nozzle (XL single-tool)</a></li>
<li><a href="https://www.printables.com/model/786649-xl-nozzle-replacement-tool">How to replace the Prusa Nozzle (XL single-tool) using the XL Nozzle Replacement Tool</a> (instructions in the description on Printables.com)</li>
</ul>
<p>XL Multi-tool</p>
<ul>
<li><a href="http://help.prusa3d.com/guide/how-to-replace-the-prusa-nozzle-xl-multi-tool_506481">How to replace the Prusa Nozzle (XL multi-tool)</a></li>
<li><a href="https://www.printables.com/model/786649-xl-nozzle-replacement-tool">How to replace the Prusa Nozzle (XL multi-tool) using the XL Nozzle Replacement Tool</a> (instructions in the description on Printables.com)</li>
</ul>
<p> </p>


Changing or replacing the Prusa Nozzle

<p>Replacing the Nextruder Hotend assembly on your printer may differ depending on the specific model you own. This article outlines various approaches for replacing the Nextruder Hotend and guides you to the correct instructions for your printer model.</p>
<p><img decoding="async" style="display: block; margin-left: auto; margin-right: auto;" src="https://cdn.help.prusa3d.com/wp-content/uploads/2024/08/37a78f7bfaa93b2dfce96c3e72d670da_painted.jpeg" sizes="(min-width: 1024px) 820px, 100vw" srcset="Changing or replacing the Nextruder Hotend" alt="" width="50%" /></p>
<h3>Do I have the Nextruder Hotend on my printer?</h3>
<p>Every MK4S, MK3.9S, MK4, MK3.9, and XL printer is equipped with a Nextruder Hotend.<img decoding="async" src="https://cdn.help.prusa3d.com/wp-content/uploads/2024/08/37a78f7bfaa93b2dfce96c3e72d670da_painted.jpeg" sizes="(min-width: 1024px) 820px, 100vw" srcset="DSC_1096.jpg" alt="" width="NaN" height="NaN" loading="lazy" /></p>
<h3>Methods for replacing the Nextruder Hotend assembly:</h3>
<div class="note-callout">All methods listed below are fully compatible with both Prusa Nozzle and Prusa Nozzle CHT diameters.</div>
<div>MK4S/MK3.9S</div>
<ul>
<li><a href="http://help.prusa3d.com/guide/how-to-replace-a-hotend-assembly-mk4s-mk3-9s_765342">How to replace a hotend assembly (MK4S / MK3.9S)</a></li>
</ul>
<div>MK4/MK3.9</div>
<ul>
<li><a href="http://help.prusa3d.com/guide/how-to-replace-a-hotend-assembly-mk4-mk3-9_645439">How to replace a hotend assembly (MK4 / MK3.9)</a></li>
</ul>
<div>XL Single-tool</div>
<ul>
<li><a href="http://help.prusa3d.com/guide/how-to-replace-the-hotend-assembly-xl-single-tool_409911">How to replace the Hotend assembly (XL single-tool)</a></li>
</ul>
<div>XL Multi-tool</div>
<ul>
<li><a href="http://help.prusa3d.com/guide/how-to-replace-the-hotend-assembly-xl-multi-tool_573711">How to replace the Hotend assembly (XL multi-tool)</a></li>
</ul>


Changing or replacing the Nextruder Hotend

How to replace a Heatbed Thermistor (MK4/S, MK3.9/S, MK3.5/S)

How to replace the Prusa Nozzle (MK4S/MK3.9S)

How to replace a print fan (MK4S / MK3.9S)

Filament Guide addon (MK4S/MK4)

How to replace Loveboard (MK4S/MK4/MK3.9S/MK3.9)

How to replace the silver PSU with the black PSU

How to replace a hotend assembly (MK4S / MK3.9S)

How to install the Nextruder V6 Nozzle Adapter (MK4S/MK3.9S)


<ul>
<li>Prusa Connect integration</li>



<li>Prusa Account integration</li>



<li>Improved UI</li>



<li>Improved G-code Viewer</li>



<li>New system profile updating system</li>



<li>Single Perimeter for top and bottom layers</li>



<li>Extended SLA layer separation configuration</li>



<li>Bug fixes</li>
</ul>


2.8.0

1.00


<ul>
<li>Issues with numeric keyboard repaired (MK4/S, MK3.9/S, MK3.5/S, XL)</li>



<li>Returned nozzle diameter setup (XL)</li>



<li>Printhead position during calibrations changed (MK4/S, MK3.9/S, MK3.5/S)</li>



<li>Cold pull (XL)</li>
</ul>


6.1.3


<ul>
<li>Improved menu bar, the menu no longer hides under a button</li>



<li>Two new parameters (Abrasive material and High flow nozzle) for G-Code checks</li>



<li>Improved automatic orientation of bridges</li>



<li>Number of bugfixes</li>
</ul>


Original Prusa MK3.9S

Articles