Re: CNC coil winder traverse

OK, I will start with the application and then why I want to have a
precision guide and then perhaps someone can tell me if a belt driven
servo system with linear encoder will do the job well :)

The application is in the production of magnetic actuators for the
control of micro model aircraft. They typically weigh <1g and are
free standing air wound coils using an adhesive to stick the wire
together.

for more info see:

http://rcgroups.com/links/index.php?
sid=498277416&t=article&cat=232&id=4051

Raylex:

Why do I want perfect wound? Well it is for many reasons, if gives a
coil with more turns for a given resistance and that provides more
torque. It also gives a coil with a repeatable outside dimension and
that helps in using the coil in actuator assemblies. And finally to
produce professional looking results.

I realise they are not forced to be perfect wound but it must be very
repeatable and precise.

Sheldon:

I have seen the self correction thing before and it looks very nice
but I suspect it maybe a little involved for what I am doing. I work
with microscopes and CCD cameras every day and can think of a few
ways to build a system like that based on "machine vision" but I
don't think I would have the time or the drive to do it.

My coils are designed based on the drive circuit that will be used.
Some are only rated at 25mA@5v (eg direct drive from pic) so are
around 200mA, to maximise turns they tend to use 0.05mm wire.
Dimensions are based around those of the magnet used.

John:

Thanks! My comments on ballscrew lead error were based on the info I
got back from a couple of manufacturers I got quotes from. Obviously
some are better than others.

I hadn't considered a std leadscrew with anti backlash nut because
for some reason I had got it into my head that ballscrews were the
king in terms of backlash, indeed as my "machining" forces will be
next to nill it does make sense. Do you have a web link for BS&A? I
will check them out. What are these screws like in terms of wear?
Can I depend on them after many many cycles? Can I also thank Vajk
who emailed me with similar comments.

Group:

If I cannot find a leadscrew that suits my fancy then will my servo
system of linear encoder, beltdrive and servo motor be suitable?

Thanks

Graham