Re: [CAD_CAM_EDM_DRO] Re: Very small miller/engraver

Only problem with using optical stages for machining is that they don't
take side loads well. They're basically four centerless-ground shafts,
two on the base, two on the slides, with precision ball bearings rolling
in between. Put enough of a side load on one to damage a ball or a shaft,
and it's ruined.

But! Since you're talking about using sub-mm tooling, the loads might not
be that high. I'd definitely want to test before risking one of those
stages.

Tom

On Sat, 2 Mar 2002, John H. wrote:

> > P.P.S. I will be offering plans for this bigger small mill w/
> > toolchanger, which is derivative, but not a copy of, the maxnc plans.
> > (hint: I've been playing with the IDEAS used in dental handpieces for
> > use in small machine spindles). But my first 2 books are ahead of
> > these plans in the pipeline.
>
> I've been wondering about just how small you could go with a home mill. And
> then I had this brilliant plan that no one else has ever had before [grin]
> while I was reading my Edmund Optics catalog. Why not use positioning stages
> for moving optical components around? I had a bit of a read on Edmund's site
> about them and you can get some with a few centimetres of travel on the X &
> Y for about $250 - $350. What's great about them is their precision,
> claiming to have 2 MICRONS of table wobble and deviation.
>
> I began thinking how easy it'd be to knock together these together since
> they are sold as modules and are sold specifically for 'knocking together'
> on optic position tables. It gets better when they start offering rotary
> tables, now we can mill micron size engine spindles. : ) The bite? Check
> out how much they cost with the motors and controllers fitted. $350 becomes
> $3500. I'm guessing this is because they appear to use a planetary gear set
> and also the controller looks flashy, with possible L.E.D'age. But would
> there be any way other than planetary gears to achieve accuracies in
> transmission that would be suitable for these tables? Would a toothed belt
> and gear be too innaccurate? If it is, what's used on the big high accuracy
> mills?
>
> My thoughts ran to building a 'mill' from these modules and mounting a
> spindle like a dentists hand piece like you say, so sub 1mm tooling could be
> used. I'm quite interested in steam engines and building my own machines at
> some point but I'm also really interested in all this sub-micron and nano
> machining that's going on. These optical tables offer quite a cheap way to
> obtain micron accuracies and would let you mill things that appeared as
> monster sizes on the mill even if they measured just 1 cubic cm in all. I
> wondered also about thermal stability as heat generated by the tip might be
> a problem when it warms up the table. Flood cooling = bad plan due to the
> slides being uncovered, bare really. Hand pieces like the Turbo-Carver vent
> the air they drive their turbines on so perhaps this would be enough to cool
> the bit?
>
> If it was possible to drive these positioning stages cheaply enough it would
> be interesting to see what could be made. Some of the things I've seen on TV
> that were made by nano machining with lasers are mind blowing. I saw one
> inparticular about nuclear weapons and part of the program to keep their
> workers interested is nano engineering of mirror assemblies. The mirrors
> slide up just as the bomb detonates to reflect the radiation and concentrate
> it in some form. The entire mirror assembly was smaller than a little bug
> they had running around on it. Little tiny cute motors and gear sets making
> it flash. Real cool.
>
> John H.
>
>
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