MPSM V2 Improved Extruder (WK9)

###WK9 Extruder
####MPSM V2 Extruder Replacement.
#####Wiley Kyoto

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This is an upgraded extruder meant to work with the MPSM V2 stock hardware (mid 2017 - 2022? See Version Compatibility Note below). The only exception for parts are the Bowden tube fitting and bearing screw. Part of the reason to upgrade is that the stock Bowden tube fitting isn't a standard part, so when it breaks you'll need an alternative. Also The stock extruder arm is prone to breaking where it holds the bearing in place. This extruder is meant to work with a PC4-M6 Bowden Tube Fitting and an M6 nut, to replace the weird stock fitting. Optionally you can use a bowden fitting with the extruder arm (see WK9_Extruder_Arm_Bowden.stl for this option), if you have a Bowden tube running to a dry box. This extruder is also meant to work with a 10mm long M4 screw, to hold the bearing in place. You can pick up a PC4-M6 fitting online easily and you should be able to find an M6 nut and M4 Screw at your local hardware store. The M4 screw could also be a #8 x 3/8" imperial machine screw.

VERSION COMPATIBILITY NOTE:
Some printers come with a different arm bushing design. If your extruder has a metal bushing inserted into the arm with an M3 screw holding it down, then this design should work for you. However, if your arm mounts/pivots differently you can try this arm instead: https://www.thingiverse.com/thing:2848474/comments

Stock parts:

• M3 Stepper Mounting Screws
• Arm Bushing
• Spring
• Bearing (4x11x4)
• Feeder Gear

Needed parts:

• PC4-M6 Pneumatic Straight Fitting, for 4mm OD tubing. (x2 if you use WK9_Extruder_Arm_Bowden)
• M6x1.0 Nut (x2 if you use WK9_Extruder_Arm_Bowden)
• M4 Screw, 10mm long. (or #8 x 3/8" Imperial Machine Screw)

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Notes:

• I printed this with PLA (Hatchbox - Pantone Yellow C), 0.175 Layer Height, 1.05mm wall thickness (3 shells), 20% infill, no supports, no raft.

• If you just want to print a replacement Arm, the only extra part you'll need is an M4 screw 10mm long.

• The Extruder Cap (which holds the bearing in place) comes in 4 different tolerances, I
  recommend using whichever fits in the tightest, as it helps properly support the bearing. I used the .00mm tolerance version, and it snapped securely in place. You'll want to flip this part over in your slicer (top down)

• The Extruder base has a 4mm hole leading up to the slot that takes the M6 nut. This is meant so you can put a small length of PTFE tubing (<20mm), cut with a V shaped point (when looking from above), so that it nestles in between the drive gear and bearing (without touching). This helps guide the filament through the extruder and will allow you to print flexible filaments like TPU.

• The Motor Spacer is only if your motor sticks out through the hole in the chassis too much.(Can be an issue on some MP Mini Deltas) Adjust the verticale scale in you slicer to make it only as thick as you need. The part is 2mm thick, so if your motor is sticking out 1mm, set the z scale to 50%. Warning, this may affect the allignment of the extruder gear with the bearing and filament path. You may need to slide the extruder gear farther in or out accordingly.

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Acknowledgements:
Shout out to robin7331 and his MPSM Extruder Baseplate V1 for the idea to make a slot for a nut to work with a PC4-M6 fitting.