ACE Pro PTFE / Bowden Tube Secure Guide

Updates

Rev13 (2025-09-11)

• Riser now optimized for printing in the flat orientation - compatible with the previous release's base.
• Riser PTFE "notch" has been reduced a bit for a better grip.
• Base updated to provide tension against the ACE Pro's front bar to provide some friction to keep it in place.

Description

There are quite a few filament guides out there for the ACE Pro. One of the simplest designs is to replace the stock filament guides near the front of the ACE Pro, use a PC4-6 or PC4-10 PTFE adapter, and then extend some PTFE tubes to assist with retractions back onto the spools. Some examples:

https://www.makeronline.com/en/model/ACE%20Pro%20PTFE%20Tube%20filament%20guide%20(PC4-M10)/102308.html

https://www.makeronline.com/en/model/ACE%20Pro%20PTFE%20Tube%20filament%20guide%20(PC4-M6)/183654.html

https://www.makeronline.com/en/model/ACE%20Pro%20ECAS%20Filament%20Guide/161376.html

While this design is effective at eliminating filament retraction and spool winding issues, there is a chance for the PTFE tube to be caught on the side of a spool with holes and cutouts. This will jam the spool and prevent rotation, possibly breaking the filament as the ACE Pro attempts to buffer more filament for the printer. If the filament does not break, the printer will report that there is a filament tangle problem and pause the print.

This secure guide model is an add-on to any of the examples above or of similar design - you will need one of those in addition to this model for the "complete" package. This secure guide model secures the PTFE tube at the end so that it cannot rotate too far to the left and right and get caught in the spools. It is modular in design, featuring two pieces 1) the base that attaches to the silver bar at the front of the ACE Pro 2) a riser that was designed to position itself so that the PTFE tube can be "clipped" into place at its end. The riser slides into the base with a snug fit. The orientation of the risers in the 3MF project I uploaded is flat. The original orientation was vertical, but that resulted in a 50/50 success due to the nozzle bumping the model. There are thin supports that secures the portion of the riser that gets inserted into the base. You will want to clean the thin supports to ensure proper fit. Since I changed the orientation, I may upload an updated version that doesn't require this support. But, as pictured, a little cleaning will result in a perfectly fine part.

I always keep the ACE Pro at the 45C since I usually have PLA loaded. My test samples were printed in PLA and works well, but if you bump the temperature of the ACE Pro for PETG/ABS/ASA filaments, print it in PETG. My final versions were printed in PETG, with the riser and the base mating just fine, and provides enough flexibility to deal with the tug of the filament when the ACE Pro buffers/loads filament.

This works with the ACE Pro for the Kobra 3, Kobra 3 Max, and the Kobra S1 (including the acrylic guides in the lid).