Interlocking Part Woes

I’m trying to print a Thingiverse object:

My first attempts have failed miserably. Breaking parts free was a challenge but even then I couldn’t get this to spin freely. Eventually forcing it caused the outer ring to break. Looking at the individual parts, it seems that at those points where the print head had to jump from one gear to the next, the gears were very ragged; so much so that the ring breaks trying to spin through those areas.

I printed this using nGen using the medium quality profile in Cura. Is this a retraction issue? Does anyone have thoughts on what I might tweak to make this work? Different filament, different Cura settings, design adjustments???

Thanks in advance for your help.

Just a follow-up here. I was watching the gCode execute (using OctoPrint) and this wasn’t a retraction issue. On each layer, the individual gears in this object printed separately. I believe what was going on was different than my first thought. When layer of an internal gear was printed, the section near the rim and the rim itself were hot enough to fuse. I had the filament temperature set to 230C, the middle of the nGen range. I think that if I set the temperature to 220C, it might minimize that fusing.

Recently (after the print I described above) I swapped out the .5mm hot end for the .35mm hot end. As an experiment I printed this again at 230C and did not have the fusing problems. My operating assumption is that the thinner filament lines cooled more quickly and were therefore less likely to fuse with the surrounding sections.

Try reducing your flow to 90% - 95%, that should help create more space betwen adjacent gears and outer ring. Lower flow, should make each gear a bit smaller, and the outer ring I.D. will get bigger. Essentially creating a bit more space between adjacent parts.