MMU Air Buffer V1

Why?

I was tired of failures due to extra resistance and odd angles for the PTFE tubes on my MMU so I created the Air Buffer V1.

I was inspired by this “air buffer”: https://www.prusaprinters.org/prints/30793-mmu-air-buffer-auto-rewinder

How To Achieve Success!

1. Upgrade the external PTFE tubes to 4mm outside diameter, 3mm inside diameter. Anything from the filament spool to the MMU and from the MMU to the extruder head.  I needed two orders of the following:
   1. https://www.amazon.com/gp/product/B07B8CK8L9/ref=ppx_yo_dt_b_asin_title_o08_s00?ie=UTF8&th=1
   2. NOTE: this tubing isn't high quality stuff, you can visually see differences in the thickness of the tubes, but it seems to work fine in this application.
2. Upgrade the MMU's rear PTFE infeed holder to prevent kinks and allow smooth transition of filament into the MMU.  I used this:
   1. https://www.prusaprinters.org/prints/6605-prusa-mmu2-ptfe-holder-m10-passthrough-adapter
   2. You may need to order the PC4-M10 male connectors if you don't have them on-hand:
      1. https://www.amazon.com/gp/product/B01KHN1HWY/ref=ppx_yo_dt_b_asin_title_o00_s00?ie=UTF8&psc=1

Other Items Not Created by Me:

1. This is the wall mount I'm currently using to hold the filament spools.  There is nothing special about this, but I had them printed so I used them (they are lengthy prints).  But it is what I used to mount my air buffer to, so the air buffer is specifically designed to fit this:
   1. https://www.thingiverse.com/thing:4001586
2. Nuts and bolts
   1. I went to Lowe's and bought some hardware a long time ago so I don't have specifics.  Here are the measurements:
      1. Shaft length: 37.5MM
      2. Shaft diameter: 12.55mm
      3. Plus the nuts to match

The Air Buffer:

1. There are three printed parts to my MMU buffer solution:
   1. wallMountFilamentAirBuffer.stl
   2. airBufferBoltHolder.stl
   3. filamentPassthrough.stl
2. Printing:
   1. No Supports
   2. Printed in PETG (PLA should be fine)
   3. Layer height: 0.2
3. Assembly:
   1. Glue the offset part of the wallMountFilamentAirBuffer to the wall mount.  Lightly sand both parts and use super glue:
      1. 
   2. Add the PC4-M10 Male pass-through connectors at the front.  Note, the print is non-threaded so the hardware will cut the thread, there is a 13 degree angle to the PC4-M10 hole.
      1. 
   3. Insert a small piece of 4mm O.D. 3mm I.D. PTFE tube to feed the filament from the spool through the support, I used hot glue to hold in place:
      1. 
   4. Create the bolt holder filament weights:
      1. Attach the two parts (airBufferBoltHolder.stl, filamentPassthrough.stl) with super glue after the filament pass-through feet are inserted into the bolt holder.  Note I friction fit a small section of 4mm O.D. 3mm I.D. PTFE tube into the hole at the top of the filament pass-through:
         1.