Re: motor sizing vertical slide EDM

Graham,

>Message 8
> From: "Graham Stabler" eexgs@...
> Date: Thu May 11, 2006 9:34am(PDT)
>Subject: Re: motor sizing vertical slide EDM
>

I keep picturing the cables to the counterbalance going limp then taut
but the weight never moving ;-)
I think I'mpicturing the inertia of the balance being larger than the response
I'm looking for.

>Would it be stupid to say the word counterbalance?
>

Peter Deckel made a beauty of a machine in the 70's (?) that had a
dual Z design. ( like Z & W , colinear ). Ran nice, but didnt sell.
Actually I've been thinking the same,
While looking into orbiting head, I though of adding a bit-o-Z to it.
Just a couple mm, so the main axis never moved from the bottom of the cut.
Let WUV axis orbit about that position byt 1mm.
1mm oughta be enuf for all but honking great 300+ ampere cuts.
Subject to extreme heating tho...

>It gets me wondering about EDM machine construction in general, you
>end up with a lot of mass to keep things stiff and steady but then you
>have to move that mass preferably with a fast response even if over
>VERY short distances. Wouldn't it be cool if you could mount the tool
>on some sort of piezoelectric stack or similar and let that do the
>fine high response adjustment and then let a fairly lowly servo system
>do the slower "drift" of the tool. Or something like a stiff flexure
>capable of only very small motions in z actuated by a small fast servo.
>

well, not a shetland, but a healthy Cairn terrier ;-)
( no exaggeration, 12x24x12 typical ) buried to the platen.

>Then again if your tool is the size of a small horse that's not going
>to work anyway.
>
>Graham

Thanks, tomp