6. Preflight check

Relevant for:

MK4S MK3.9S

Last updated 2 months ago

Difficulty

Easy

Steps

Available languages

Step 1 Attaching the steel sheet

Make sure there is nothing on the heatbed. The heatbed must be clean. Any dirt can damage the surface of both the heatbed and the steel sheet.

⬢Attach the sheet by first aligning the rear cutout with the locking pins on the back of the heated bed (marked in orange in the picture above). Hold the sheet by the front two corners and slowly lay it down onto the heated bed - watch your fingers!

⬢Keep the steel sheet clean for optimum performance.

⬢#1 cause of prints detaching from the print surface is a greasy steel sheet. Use IPA (Isopropyl alcohol) to degrease it if you have touched its surface before.

We are using a steel sheet with a smooth surface. However, the same procedure applies to other variants.

Step 2 Firmware updating

⬢On your computer, go to:

⬢prusa.io/mk4s to open the MK4S support page

⬢prusa.io/mk3-9s to open the MK3.9S support page

There, you will always find the latest firmware, handbook, and PrusaSlicer for your printer.

⬢Download the latest firmware and save it to a USB drive.

The firmware file has a .bbf extension.

Step 3 First run

⬢Insert the USB drive with the latest firmware into your printer.

⬢Connect the power cable and connect the printer into a wall outlet.

⬢Turn the printer on using the switch on the back.

The printer will now detect if a new firmware file is available on the USB drive.

⬢If the "New firmware available" screen appears, hit FLASH by pressing the rotary knob to upgrade to the latest firmware.

⬢If no such message appears, the printer is running the latest firmware already. Proceed to the next step.

Step 4 Printer setup

⬢After upgrading to the newer firmware, navigate to Settings -> Hardware.

⬢On the following screen, select your printer type: MK4S or MK3.9S

⬢Leave the other items unchanged unless you have installed custom parts on the printer (e.g., nozzle with a different diameter, silicone sock removal).

⬢Go to Settings -> Hardware and check that the Nextruder Silicone Sock option is set correctly, depending on whether or not you have the Nextruder Silicone Sock installed on the hotend.

Step 5 Wizard - Selftest start

⬢Now, let's run a self-test to check the entire printer and ensure everything is plugged in and assembled correctly. The entire process takes a few minutes, with some parts requiring direct user interaction.

NOTE: While testing the axes, make sure that there is nothing in the printer obstructing the axes movement.

WARNING: Do not touch the printer during the self-test unless prompted! Some parts of the printer may be HOT and moving at high speed.

⬢The wizard starts with the fan check, Z-axis alignment and the X&Y axis test; all fully automatic.

⬢Go to Control -> Calibrations & Tests and select the first test in the list: Fan Test.

The printer remembers the results of each test from the last time the self-test was run. Thus, you can see all test items marked as completed. However, run the self-test again.

⬢After completing the fan test, you will be asked to end the self-test or continue with the remaining tests. Select Continue.

Step 6 Wizard - Loadcell Test

⬢The next step of the wizard will prompt you to touch the nozzle to test and calibrate the Loadcell. During this procedure, the parts of the printer are not heated up so that you can touch them. Click Continue.

⬢Do not touch the nozzle yet, wait until prompted by the Tap nozzle NOW message.

⬢Tap the nozzle from below. In case the Loadcell does not detect the touch, you will be prompted to repeat the step. Otherwise, you will see Loadcell test passed OK when it succeeds.

Step 7 Wizard - Gearbox Alignment

⬢Once you get to the Gearbox Alignment part, select Continue and follow the on-screen instructions.

⬢Undo the idler lock (swivel), then open the idler door.

⬢Loosen the three screws on the front of the gearbox by 1.5 turns.

The printer will go through the automatic gearbox alignment. This process can’t be seen from the outside.

⬢Once prompted, tighten the three screws in the pattern indicated on the screen.

Step 8 Wizard - Filament Sensor Calibration

⬢During the filament sensor calibration, you will need to use a short piece of filament. Prepare the filament and select Continue.

There should be no filament inside the extruder before the calibration process starts.

⬢Once prompted to, insert the filament end into the opening on top of the extruder.

⬢Remove the filament after the calibration finishes.

Step 9 Haribo time!

⬢Congratulations to all those who patiently ate according to the instructions. Eat the rest!

Step 10 Loading a filament

⬢Place the spool holder back on the printer frame.

⬢Add a spool or a sample of your favorite filament onto either side of the spool holder.

⬢Guide the filament end through the filament guide into the extruder. Using the filament guide prevents filament tangling.

⬢Once a filament is detected, the printer will load it automatically. It is important to select the correct type of filament you are using on the screen. We recommend using PLA material for the first test print.

⬢The printer will purge some of the material through the nozzle. Confirm its color is clear by selecting YES on the screen and remove the leftover plastic from below the nozzle.

Proceed carefully, the nozzle is now very HOT! Do not touch it with your bare hands!

Step 11 Printable 3D models

⬢The printer is now ready to print!

⬢You can start by printing some of our test objects from the bundled USB drive.

⬢The sample objects are also available on the official Prusa Research Printables profile

Step 12 Network setup: Prusa Connect (Optional)

⬢Don't forget to add your printer to Prusa Connect to remotely control and monitor all your printers. However, it is optional and can be done at any time.

For more informations read the article Prusa Connect and PrusaLink explained.

⬢Use the official Prusa mobile app to add your printer to Prusa Connect, allowing you to manage it anytime via the app.

For further details, check out the Prusa Mobile App article.

⬢If you need to connect your printer to a network, you have several options available.

All available methods are outlined in the Network Connection article.

Step 13 PrusaSlicer

⬢Ready to print your own models?

⬢Visit help.prusa3d.com once again. Download and install the latest Drivers & Apps package onto your computer. This package includes the PrusaSlicer app.

⬢Open the PrusaSlicer app. If you’re running it for the first time, Configuration Wizard will show up. Visit the Prusa FFF tab in the Wizard, select Original Prusa MK4S or MK3.9S in the 0.4mm nozzle version (the default nozzle size) and hit Finish to start using the MK4S printer profile.

⬢Make sure the Original Prusa MK4S or MK3.9S is selected in the Printer menu on the right, when slicing for the MK4S/MK3.9S.

⬢Import a model of your choice into PrusaSlicer, adjust the settings if needed, hit Slice and export the G-code file onto the USB drive to print it on your MK4S/MK3.9S.