6mm to 4mm PTFE tubing adapter

thingiverse

This adapter is specifically designed for upgrading from 4mm to 6mm OD Bowden tube. It securely plugs into the end of a Festo fitting for 6mm OD tubing and provides a seamless transition to 4mm. The adapter is fully compatible with PTFE tubing commonly sold for 3mm filament, such as https://amzn.to/2H6VFrK. Using 6mm tubing is highly recommended in situations where the filament spool and printer are separated by a long or curved route because it significantly reduces friction on the path. I personally use 6mm PTFE between my drybox and MMU2S filament buffer (https://www.thingiverse.com/thing:3399360). This adapter works seamlessly with both passthrough and non-passthrough fittings, including PC6-M10*1 style (https://www.captubes.com/shop/#!/4-Pack-PC6-M10*1-Fittings-For-2-85mm-Bowden-Tubing/p/103148418/category=33913105). To achieve the best results, print this part at ultra-fine resolution and 100% infill due to its thin object wall. ABS or PET filament is preferred; however, PLA might be too brittle for this part. You may need to clean up the chamfer with a drill bit after printing. First, insert the tubing into the Festo fitting, then firmly push the plug into the fitting.