This guide will take you through the replacement of the heatsink on the Original Prusa MINI and MINI+.
Before these steps, it is recommended to protect the heatbed!
Take off the flexible steel sheet.
Use any cloth or piece of fabric, which is thick enough and cover the heatbed. This will ensure you won't damage (scratch) the surface during the disassembly.
Loosen the upper fitting and remove the long PTFE tube from the hotend.
The new design without a zip tie: Gently pull out the textile sleeve from the MINI-fan-spacer-clip. Do not pull on the cables!
The old design with a zip tie: Cut off the zip tie on the print head. Avoid cutting the print fan cable!
New design - the MINI-minda-holder is mounted to the hotend fan.
Loosen and remove both screws on the fan.
Carefully pull the print fan from the x-carriage and remove it.
Hold the heatsink with hand.
Use your other hand to release the upper screw on the x-carriage and remove the heatsink from the printer.
CAUTION: Don't drop the heatsink on the heatbed!
For the following steps, please prepare:
New heatsink (1x)
Thermal paste (1x)
Hold the heatsink with hand.
Use the other hand to secure the heatsink with the upper M3x20 screw.
Insert the edge of the fan's casing inside the bottom of the x-carriage.
Rotate the fan into the x-carriage.
Align the hole for the screw in the fan with the hole in the x-carriage.
Insert and tighten the screw.
Place the hotend fan on the MINI-fan-spacer. Align the holes against each other.
The "teeth" for the MINI-fan-spacer-clip must be oriented upwards to the left.
The fan cable must be facing the upper left.
Place the hotend fan with MINI-fan-spacer on the heatsink. Align the holes for the screws on the fan with the holes on the heatsink.
Secure fan and the spacer with two M3x20 screws.
Ensure no cable is pinched!!!
Make sure the fan cable and fan-spacer protrusion is facing the upper left like in the picture.
Place the hotend fan with fan-spacer on the heatsink. Align the holes for the screws on the fan with the holes on the heatsink.
Insert and tighten the two M3x20 screws. Tighten carefully, you can crack the plastic frame of the fan, also ensure no cable is pinched!!!
Release and remove the "lower" fitting from the heatsink.
Insert and gently slide the hotend into the heatsink. Make sure the nozzle cables are on the left side.
Hold the heaterblock with the other hand.
Slightly tighten three screws on the side. You will loosen them again later.
Remove excess paste with a paper towel or a cotton bud.
If you have a version with the textile sleeve secured with a zip tie on the print head, skip this step.
Wrap the cable bundle inside the textile sleeve.
Slide the textile sleeve into the MINI-fan-spacer-clip so that it extends over the 2-5mm textile sleeve from the other side.
Now skip to Hotend PTFE tube installation
This step is for the version with the textile sleeve secured with a zip tie on the print head.
Wrap the cable bundle with the textile sleeve.
WARNING: Don't overtighten the zip tie around cables, leave some slack or you might break some of them!
Secure with a zip tie to the fan-spacer.
Double-check all cables aren't stretched, if so, please cut the zip tie, make them slightly more loose and tighten the zip tie again.
Use your phone LED flash or similar device to shine into the hole from the top of the print head. Take a look inside and check there is no filament. It must be clean and you should see only the metal surface inside. Open the full-size image if needed.
A clean print head is essential for successful prints. Double-check, there is no filament inside!!!
Insert and push the PTFE tube into the heatbreak all the way down.
Orientation of the PTFE tube installation does not matter. Both ends are symmetrical.
Loosen tree screws on the side of the heatsink with 1.5 Allen key.
Push the nozzle up. You must see the PTFE tube moving up a bit.
Mount the "lower" fitting to the top of the heatsink. Screw it all the way, but don't tighten it. As soon as you reach the end of the thread, release it by a full turn (360°).
Push the heaterblock up against the fitting with a reasonable force. No need to bend the entire axis. This will pre-stress the PTFE tube inside. Now, it is important to keep the pressure.
Make sure the heaterblock is aligned with the heatsink. If not, realign it, but keep the pressure.
While holding the heaterblock from below (pressing the tube inside), tighten all three grub screws.
Now, you can release the heaterblock. Make sure it doesn't move. If so, the grub screws were not tightened properly. Release them and return to the beginning of this step.
It is crucial there is no gap between the PTFE tube and other parts of the hotend. This is why we are "pre-stressing" it.
Finish tightening of the "lower fitting", you should do a full turn to compensate for the turn we did in the previous step.
Mount and tighten the upper fitting with the long PTFE tube.
If you have a question about something that isn't covered here, check out our additional resources.
And if that doesn't do the trick, you can send an inquiry to [email protected] or through the button below.
