Prusa MINI/+ Extruder Filament Sensor

Dry filament before print.

*ver1, ver2 are normal PC4-M8 fitting version(mini default). If you are using E3D Revo Micro and Bondtech PTFE Fittings Set there will be an extra PC4-M8 (did not test with other PC4-M8 but you can try it).

*ver3, ver4 working with PC4-M10 fitting, easy to get than PC4-M8.

*MINI-z-carriage-rear-s is optional cover the back side.

*c has more tolerance than b, b has more tolerance than a, try use lever a2/b2/c2 if you cannot put normal ver in.

*some photos are old ver, the magnet slot is a bit different.

Size:

56.70/62.57mm * 67.86/67.87mm * 17/17mm (MINI-extruder-rear-s ver1/2)

13.35mm * 13.65mm * 10.6mm (lever)

55.1mm * 56mm * 14mm (MINI-z-carriage-rear-s optional)

Weight (at 0.2 layer height):

19.89/19.8± 6.51/6.48m± (MINI-extruder-rear-s ver1/2)

0.58g± 0.19m± (lever)

16.63g± 5.44m± (MINI-z-carriage-rear-s optional)

Slicer setting (default presets):

• Layer height 0.15-0.2
• Filament PETG/ASA etc.
• Nozzle 0.4mm
• NO support

Prepare (found in spare):

• MINI-extruder-rear-s ver1/2 (1x), lever (1x)
• Optional MINI-z-carriage-rear-s (1x)
• Allen key 1.5mm, 2.5mm
• M3nS nut (1x)
• All other are reuse, keep leftover in spare
• Cloth or fabric covering the heatbed

Step:

Optional: 

Follow https://help.prusa3d.com/guide/3-x-axis-extruder-assembly_199519#200332 to prepare new MINI-z-carriage-rear-s.

Holding X-axis at the front by hand when uninstall MINI-z-carriage-rear, Remove M3x20 screws (1x) at the bottom, and M3x30 screws (4x) from the back.

Swap with X-axis and MINI-z-carriage-rear-s and install everything back, keep other parts as spera. 

Prepare:

• Disassemble Filament Sensor.
• Red square keep as spare.
• Reuse Magnets (2x), Steel ball (1x), M2x8 screw (1x).

• Using cloth or fabric covering the heatbed.
• Disconnect PTFE tube from PTFE Fitting.
• Hold the motor and remove M3x25 screws (2x) from the back.
• Place extruder on table/heatbed.

• Remove M3x25 screws (1x) from the back and M3x40 screws (1x) and idler from the side.

• Remove all M3x25 (3x) and M3x12 (1x) screws.
• Remove Bearing 625 2Z (1x), M3nN nyloc nut (1x), M3n nut (1x), PTFE Fitting (1x).

Install:

• Red square - keep as spare.
• Blue square - only use in ver1/3 M3x12 (1x), M3n nut (1x).
• Yellow square - found in spare M3nS nut (1x).

• ver2/4 insert M3x40 screws (1x) with spring before screw bottom PTFE Fitting in.

• Put steel ball into the MINI-extruder-rear-s and make sure it can move freely in the tunnel.
• Put Magnet into Lever from the opposite side as picture. 
• Make sure pole facing. Use allen key push 2nd Magnet all the way in MINI-extruder-rear-s holder (yellow arrow, if not all the way in it will be hard to use with TPU).
• Insert lever into MINI-extruder-rear-s from the flat side.

• From side with R1 mark insert bearing (1x) and M3nN nut (1x) into the MINI-Extruder-rear-s. 

• ver1/3 insert the M3n nut (1x) from the opposite side. 

• insert M3nS nut (1x) from top.

• From the cut at bottom push sensor wire and sleeve in and install filament sensor (open the bottom cover to move more sleeve out).
• Secure the sensor with M2x8 screw (1x) from the side (yellow circle).

• Secure M3x25 screws (1x) until the surface is flat, do not overtighten, find some filament push it in (blue arrow), do it few times make sure the lever can move freely. 
• Unscrew M3x25 screws (1x).

• Place the MINI-Extruder-rear-s on the MINI-Extruder-front, Secure parts together with M3x25 screws (3x). Do not overtighten the one with red circle.

• ver1/3 insert M3x40 screws (1x) with spring from the side.
• Follow https://help.prusa3d.com/guide/3-x-axis-extruder-assembly_199519#201258 mounting the MINI-Extruder-idler.

• ver1/3 push your PTFE tube all the way in from the side (yellow arrow, around 22mm). Make sure it is shorter than the print head PTFE tube. 
• Secure the tube with the M3x12 screw (yellow circle).

• Put MINI-Inspection-door (1x) back in, align the holes.
• Secure extruder with the M3x25 screw (2x), make sure the MINI-Inspection-door can move freely.

• ver2/4 Connect PTFE tube, make sure it is shorter than the print head PTFE tube.

*you can also put sensor wires into the other hotend sleeve with zip tie.

*there is a cut on the lever, you can use flathead screwdriver to push it down, the lever will temporary disabled.

Combined original MINI-extruder-rear and Filament Sensor to a compact design MINI-extruder-rear-s.