Creality Filament System (CFS) Rolls

This remix aims for a simple CFS-roll system. It won't win a price in mechanical engineering neither in design but its simple to make and requires no special parts. Also no TPU roll or rubber hose is necessary.

Differences to original model:

• ½ the bearings required
• larger bearings
• more robust
• simpler assembly
• sits better onto CFS lid
• no TPU/rubber roll

Before you start making, read the instructions. It will save you lot of time. I already did assemble and disassemble way too many times until the model was finished - its boring. I you follow the hints i left, it will run smoothly out of the box.

BOM for 1 roll (out of 4):

Assembly

Center part (#8):

1. Cut a 80mm piece of M5 threaded rod (#2). Don't make it exactly 82mm (rather 81mm if undecided), then you have more leeway when centering the rod). After cutting do rectify the thread on both ends nicely (use file, screw a nut or use thread cutter if available). Otherwise in the end it will be hard to screw the rolls up the rod.
2. Prepare a spacer: take 1x M5 (#3) nut and drill out the thread with 5.0mm. The nut should not be damaged, the sides need to be parallel.
3. Align and press bearing (#1) → spacer (#3) → bearing (#1) by hand for the very first millimeters.
4. Press bearings:
   1. Either use a jaw vice and 2 other bearings or 
   2. insert rod (#2), add 13mm washer (#5) and nuts (#3) and tighten all way up until the end stop.
   3. Note: This step requires the bearings to be pressed not by just tightening the inner ring, but pressing the inner and outer ring as well. Not doing so most likely won't let the rod spin freely or a rubbing effect may remain when turning.
5. Remove both washer (#5) add nuts back and center the rod (accuracy +/-0,5mm). When centered, firstly tighten the two nuts by hand, then add one more nut and counter this nut by tightening against the nut on the other side of the bearings. Repeat the step for the last nut. In the end you have: nut → nut → bearing → spacer/center-part → bearing → nut → nut - this is nuts! Make sure all counter nuts are tightened well. Now the rod must spin freely without rubbing. If not so, and bearings were pressed according to (1.4.) then most likely the inner flange was sagging (overhang) while printing and obstructs the bearing sealing or sth. obstructs the hex nut (spacer) or something is not axial. However, this is not a big deal. Loose two counter nuts, loose the inner nut and tighten it just by hand (gently) and counter again. In doubt leave a bit of leeway (think of how you wold tighten a conical bicycle wheel bearing - not too tight, not too loose). Unfortunately if you need to fine-tune, this step requires a flat wrench like the universal bicycle wrench.
6. Finally rectify the 3mm hinge-hole that connects this part with the base plate: drill once through the hinge hole with 3.0mm to increase the clearance so it can turn freely when assembled with hex screws (#4).
7. Repeat the steps for the 2nd rod.

Rolls (#9):

1. On the flat roll side cut a thread along the very first 10mm with a decent M5 screw by hand or preferably with an electric drill. With el. screwdriver, if screw becomes hot, the thread will be smoother, but you need go through once more when everything has cooled down. Otherwise its hard to screw the roll by hand. I did not try to tap the thread, pbly. that is a better approach.
2. Tighten both rolls by hand against each other. They will stop at 82mm total length. The rod, even if not centered perfectly, should not exceed the roll.
3. Repeat the steps for the 2nd rod.
4. If bearings run sluggish (i.e. if brand new + thick vaseline) the spool might slip; a shrink hose will do the trick. Personally i didn't see any slippage after fine-tuning in “Center part - (5.)”.
5. If the roll has a prominent z-seam, try to print it with aligned seam and cut the seam off with a sharp knife. I found that scarf-seam still leaves a decent mark at large layer height (0.22mm).

Base (#1):

1. Tighten four screws (#4) and let the screws self-tap the thread.
2. Clean the overshoot that is pushed out when screw goes though.
3. Unscrew the screws so that the center part can be inserted.

Assembly

1. Finally insert once center-part and tighten two screws (#4). The parts must turn freely.
2. Repeat step for the 2nd center piece.
3. Insert extension spring (#6).

Mounting

1. Disassemble and remove the gray original spring loaded blocks. I don't know exactly what the Creality guys smoke, but this piece of garbage is more than a faux pas. However, we can do it better!
2. Use same screws to fasten the new roll but: gently, do not rush, do not strip the thread and in case of doubt, first apply the screw but turn backwards until you feel/hear the click when the thread skips. Then tighten it. You don't want to cut a new thread in that plastic.

Printing:

• layer height: 0.2mm
• material: PLA+ is robust enough
• walls count: 3
• infill: 0% (max 5% rectilinear)
• top/bottom shells: 6/5
• seam: scarf, aligned
• support: 
  • type normal
  • style snug
  • on build plate only
• Parts
  • Center 
    • print with hole aligned vertically
    • align Z-seam to the V-shaped notch
  • Base: 
    • lay flat on the side that will touch the CFS lid
    • support required only for CFS-lid seat/screws (hence only on build plate)
  • Roll:
    • print with holes aligned vertically, flat side down

Source:

See also the FreeCad project file on GitHub: cfs-rolls.FCStd