Every time I use a Makerbot printer I'm impressed with what it can actually do. Thermal deposition printers can produce better precision and finer detail than many people assume.
I drew and printed these planetary gears a few days ago to reduce the output of an AC universal motor I had lying around. I also made a case that connects to outer ring to the motor (not pictured). I haven't bothered to figure it out exactly, but the reduction ratio is about 9:1. The gears are pretty standard involute herringbone gears and the Solidworks files are available here:
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Unfortunately, the gears last about 30 seconds when connected to the universal motor. When subjected to a several-thousand-RPM input, they melt. The friction is just too high, even when I vary the fit and clearance. They should work fine with lower RPMs, but they were designed to reduce inexpensive AC motors, so I'm afraid they just don't fulfill the design requirements.
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| These were the first test print. The final gears are inside a case that is super glued shut. Sorry. |
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Unfortunately, the gears last about 30 seconds when connected to the universal motor. When subjected to a several-thousand-RPM input, they melt. The friction is just too high, even when I vary the fit and clearance. They should work fine with lower RPMs, but they were designed to reduce inexpensive AC motors, so I'm afraid they just don't fulfill the design requirements.