B2D modified 1.75 bowden exit (stronger)

thingiverse

I have been heavily using the original B2D extruder for a few months and it is wonderful. It has utterly transformed my bargain basement Tronxy X3.Thanks again to original designer! However, recently during a heavy multiple retraction Veronoi print, the bowden output support failed (see pic). This may well be because I had printed it upside down so that no supports etc were needed. This meant the layers grain were clearly not optimal for component strength. This component can have a lot of force to carry when the extruder pressure is High. Luckily I had made a couple of spares so in mid print, on pause I managed to replace the broken part and resume the print job. Since the start I had noticed the part bending slightly when it is under heavy pressure load and heavy push/pull retractions. So I guess it was going to fail anyway. The whole extruder was made with PLA. So I decided to make a small mod to the part to hopefully prevent any possible future recurrences of this failure. I increased the thickness of the external bowden support plate by 50% (~2mm more, was 4mm is now 6mm). I also added a bit of sheet metal under the M3 retaining screw head to spread the considerable load better (belt AND braces!). It was necessary to use a slightly longer than original M3 screw with this mod. It appears very much stronger now and I really doubt it will ever fail again. The rest of the extruder has been totally rock solid. I think it will outlast ME! The new part is clearly visible in RED PLA on an otherwise all white extruder. PS. I also increased the filament pass through hole to 4mm in order to enable the use of a metal PTFE tube retainer that allows the PTFE to pass all the way through the assembly right up almost touching the drive pinch rollers. This just makes for easier filament inserting and hopefully less friction in the filament pathway etc.