Difficulty printing Wade's gears

I am trying to print a complete spare parts set in ABS, starting with the extruder parts. I FINALLY, after much tinkering, frustration, and many failed prints, got a good block. I had been having problems with corner lift causing distortions in the upper layers that deformed the hex holes for the bolt heads and also the socket for the hotend, as well as problems with bridges in the bearing wells. Fixed the bridging problem with speed adjustments in Slic3r (which is the only slicing program I have been able to use with any success on anything)), and ran my filament at 240 degrees with a 3 mm brim on the part.

Now, I am still having problems with my gears. If I run my heated bed at 120 degrees or more, my parts end up with flares at the top and bottom (the parts are sort of "hourglass shaped"). Run the bed at 115 degrees, and the teeth of the big gear (and the base of the small gear) start to lift off the bed. I really don't want to run a brim on gears because it would be a pain to clean off the teeth (and rafts are even worse!).

I really don't want to make the gears in PLA. I am trying to make my parts as heat-resistant as possible so that I can put my printer in a heated build chamber (or travel with it in the summer time and leave it in my car if necessary) without having everything droop (most of the parts from my current, original parts set are PLA, except the parts immediately associated with the hotend).

Any helpful suggestions?

Edited 1 time(s). Last edit at 01/28/2015 05:08AM by Rich K..

Hi,

I have printed many replacement ABS parts without these issues. I used a Chinese filament under the Reprapper brand sold by 3dfilaprint.

I set my bed temperature to 125C and hotend temperature to 220C. The parts were printed at a layer height of 0.4mm using a 0.4mm nozzle (people will tell you this is not possible but my replacement parts disagree).

I use a moderately strong ABS juice on the heated bed and print in an ambient temperature of 21C in a draught-free room. I have posted in this forum the results including the gear set you are attempting to print. Look back through my posts using the subject keyword ABS in a search to find them.

Regards,
Neil Darlow

---

I try to write with consideration for all nationalities. Please let me know if something is unclear.
Printing with Mendel90 from fedora 25 using Cura, FreeCAD, MeshLab, OpenSCAD, Skeinforge and Slic3r tools.