22 Dec
2020
22 Dec
'20
2:40 p.m.
Aaron,
One thing I would check is the motor bearings. What happens on electro
mechanical assemblies left in store for years is that ball bearing
grease lube dries out and hardens, resulting in lumpy rotation and
increased friction that can be detected by rotating the spindle by
hand. RLxx series drives were very reliable typically, but the head
movement assy is pretty cheap and cheerful. Converting spindle to
linear movement, minimum parts count, dc brush brush motor, means that
all the bits need to be smooth in operation, with no stiction anywhere
in it's travel.
I would take the motor out and if it can't be stripped to clean the
bearings, use a dab of light clock oil to relube. Also, check the
brushes and clean / polish the commutator. Any other ball bearings
in the path, same process. DC brush motors can be a nightmare for
that sort of precision positioning application...
Chris
Thanks Chris, I will look into trying to measure the wobble (if there is
any present) of the spindle. Might be a fun project to strip this down
anyway and see what's going on. Hopefully not too much more complicated
than a bicycle but we'll see...
Aaron
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