PLA should have enough flex for the part of a cycloidal drive that has to flex.
It also is pretty tough so wear would be a minimal issue. Just don't run it
fast and/or under a bunch of pressure without some lube. I suspect a silicone
grease made for plastics (like that sticky white stuff often found in gear
drives in cheaper power tools) would work for PLA.
If the part works well for a while then breaks, print another one. Print a
spare to start with to ensure the one you use lasts a long time. ;)
On Saturday, July 18, 2020, 11:04:25 AM MDT, Gene Heskett
<ghesk...@shentel.net> wrote:
Grettings all;
Using one of these 6 wire, 12 volt elderly floppy stepper driver motors,
as 4 wire on a to6600 driver I have a choice of fitting a sleeve over
the driver hub on the motor shaft, which when cleaned off is 16.8mm in
diameter, meaning the minimum tooth count for a GT2_3mm belt will be
about 24. Or I could fab a miniature gear puller and get down to the
motors 5mm shaft by pulling the existing hub, meaning I'll need to find
metal pulleys, but fleabay has only GT2_2mm for sale.
With a single reduction stage consisting of a 24 tooth pulley on the
motor, driving a 180 tooth, the resulting pointing accuracy would be
0.06 degrees.
But for astrophotography, they are mentioning .01 arc-seconds or better,
which seems a lot finer than a single reduction stage will get me to
from a 1.8 degree motor whose best accuracy will be .45 degrees.
So how much more geardown do I need? And whats the best way to do it?
I am thinking of trying to print a harmonic drive that's not any bigger
than these motors, which are 40mm square. But I can't imagine one being
under 75mm around. Maybe even ditch this idea and make a 2 stage
harmonic drive. Or cycloidal, anything these teeny motors can drive as
I can bang them pretty hard with a 24 volt supply and a tb6600 driver
set at its lowest current.
The cycloidal seems like it would be more compact axially.
Thanks.
Cheers, Gene Heskett
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