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How to replace an extruder motor (MINI/MINI+)

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How to replace an extruder motor (MINI/MINI+)

How to replace an extruder motor (MINI/MINI+)
Relevant for:
Last updated 9 months ago
How to replace an extruder motor (MINI/MINI+)
 Difficulty
Moderate
 Steps
24
 Available languages
CSDEESFRITJAPL

Step 1 Introduction

Introduction
Introduction
This guide will take you through the replacement of the extruder motor on the Original Prusa MINI and MINI+.
Some parts might slightly differ. However, it does not affect the procedure.
All necessary parts are available in our eshop shop.prusa3d.com.
Note that you have to be logged in to have access to the spare parts section.

Step 3 Preparing the printer

Preparing the printer
Preparing the printer
Preparing the printer
Make sure the printer parts - print head and heatbed are cooled down at room temperature.
Turn the printer off and unplug it from the socket!
Before proceeding any further, it is recommended to protect the heatbed first!
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.
Rotate the back of the printer towards you.
Move the heatbed all the way towards you.

Step 4 Opening the box with the electronics

Opening the box with the electronics
Opening the box with the electronics
Opening the box with the electronics
Release and remove the M3 screw on the box with the electronics.
Remove the printed cable cover.
Lift the second electronics cover slightly. Before you remove it completely, pull it first towards the vertical aluminium extrusion to release both pins from the holes.

Step 5 Disconnecting the optical sensor (optional)

Disconnecting the optical sensor (optional)
Disconnecting the optical sensor (optional)
Disconnecting the optical sensor (optional)
Disconnecting the optical sensor (optional)
If your printer does not have the optical sensor, please skip this step.
Disconnect the IR sensor cable from the Buddy control board.
Loosen the screw on the optical sensor.
Remove the optical sensor from the long PTFE tube.

Step 8 Removing the extruder motor

Removing the extruder motor
Removing the extruder motor
Removing the extruder motor
Removing the extruder motor
Cut the lowest zip tie on the extruder cable bundle mounting.
Release and remove two screws from the extruder.
Remove the inspection-door.

Step 9 Removing the extruder motor

Removing the extruder motor
Removing the extruder motor
Removing the extruder motor
Hold the extruder in your hand.
Release and remove the lower screw.
Carefully place the extruder on a piece of cloth on the heatbed so that the motor faces down.
If the extruder does not reach to the heatbed, move the Z-axis down or the X-axis closer. Do it manually, no need to turn the printer on.

Step 10 Extruder surgery

Extruder surgery
Extruder surgery
Extruder surgery
Extruder surgery
Release and remove three screws on the top side of the extruder-rear part.
Remove the extruder-rear.
Pull out the pulley from the "extruder-front" part.
Release two screws.
Remove the extruder-front part from the extruder motor.

Step 11 Removing the extruder motor cable

Removing the extruder motor cable
Removing the extruder motor cable
Removing the extruder motor cable
Pull the motor cable out of the textile sleeve and remove the motor from the printer.
Some older units may have a zip tie at the end of the textile sleeve in the electronics. Cut the zip tie.

Step 12 Removing the pulley

Removing the pulley
Removing the pulley
Loosen the set screw in the pulley. Do not remove the screw from the pulley.
Remove the pulley from the extruder motor.
Keep the pulley for the next steps. Don't throw it away.

Step 14 Extruder motor preparation

Extruder motor preparation
Extruder motor preparation
Extruder motor preparation
There is a flat part on the motor shaft, rotate it similarly to the first picture. See the direction of the arrows.
Place the extruder pulley on the extruder motor shaft as shown in the picture.
Don't press the pulley against the motor. Leave a 2 millimeters gap between both parts. You can use the 2.0mm Allen key to set the gap.
The set screw must be facing directly against the pad (flat part) on the shaft. Slightly tighten the screw.
Ensure you have the correct orientation of the pulley on the shaft. It can be placed both ways, but only one is correct.

Step 15 Installing the extruder motor

Installing the extruder motor
Installing the extruder motor
Installing the extruder motor
Installing the extruder motor
Place the extruder motor on the textile cloth on the heatbed like in the picture. See the cable direction.
Place the extruder-front part on the extruder motor diagonally, like in the picture.
For the correct orientation make sure:
The cable from the motor points away from you, like in the picture.
The bearing in the printed part is closer to you.
Secure the extruder-front part with two M3x25 screws.

Step 16 Assembling the extruder

Assembling the extruder
Assembling the extruder
Assembling the extruder
Place the pulley back into the bearing. The longer part with the jagged groove must face up. See the picture.
The gears must be aligned properly. Rotate with one pulley to ensure the second is moving as well.

Step 17 Assembling the extruder

Assembling the extruder
Assembling the extruder
Assembling the extruder
Assembling the extruder
Place the extruder-rear on the extruder-front part. Check the correct orientation of the parts as shown in the picture.
The pulley shaft must fit in the bearing.
Secure both parts with three M3x25 screws.

Step 18 Mounting the extruder

Mounting the extruder
Mounting the extruder
Mounting the extruder
Mounting the extruder
Place the extruder on the Z-carriage and secure it with the M3x25 screw in the lower hole.
Place the inspection-door to the extruder.
Make sure the holes are aligned.
Secure it with the M3x25 screw, but don't overtighten. You have to be able to open the door.
Insert and slightly tighten the M3x25 screw into the right hole. Do not overtighten this screw too much, it could cause problems with the loading of the filament.

Step 19 Connecting the motor cable

Connecting the motor cable
Connecting the motor cable
Connecting the motor cable
Connecting the motor cable
Connect the extruder motor cable (labeled E) into the fourth slot from the left.
Insert the extruder motor cable into the cable bundle mounted to the extruder.
Mount the bundle to the extruder using a zip tie.

Step 20 Installing the filament sensor (optional)

Installing the filament sensor (optional)
Installing the filament sensor (optional)
Installing the filament sensor (optional)
Installing the filament sensor (optional)
If your printer does not have the optical sensor, please skip to Covering the electronics.
Slide the filament sensor onto the PTFE tube. See the picture for the correct orientation of the sensor.
Check the position of the PTFE tube through the groove:
Wrong installation. The filament sensor is not fully pushed onto the PTFE tube. The filament sensor will not work properly.
Correct installation. The filament sensor is fully pushed onto the PTFE tube.
Now, tighten the screw gently to ensure the sensor won't slide from the PTFE tube.
Use a piece of filament and slide it through the filament sensor to ensure there is no deformation of the tube. In case of any resistance, release the screw slightly.

Step 21 Connecting the filament sensor (optional)

Connecting the filament sensor (optional)
Connecting the filament sensor (optional)
Connecting the filament sensor (optional)
Connect the filament sensor cable into the second slot from the top right side of the Buddy board.
Arrange the cable according to the picture. Keep in mind that the electronics cover must fit into place.

Step 22 Covering the electronics

Covering the electronics
Covering the electronics
Covering the electronics
Covering the electronics
Before covering the electronics, make sure the square nut is correctly positioned in the printed part. The nut must not fall out! This can cause fatal damage to the electronics.
Insert the cover back in, make sure it is properly seated in the slot. Note: on an older design, there are holes instead of slots, the assembly procedure is the same.
Place the second cover on the top and arrange the cables:
Extruder bundle, ensure the textile sleeve is partially in. Also, it must be tilted away from the printer.
Heatbed bundle, ensure the textile sleeve is partially inside the box.
Filament sensor cable (optional), ensure that the textile sleeve wrapped around the cables is partially inside the box.
Now, tighten the second cover. Check that no cable is pinched.

Step 24 It's done

It's done
It's done
Good job! You successfully replaced the extruder motor.
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