Re: [CAD_CAM_EDM_DRO] Re: OK, I've got a detent encoder... What now?

Hi Fred:
Are you SURE it has to be a number like 100 detents per turn??
I've used commercial controls with manual pulse generators for a while now,
and I can't ever remember counting either turns or clicks of the handwheel.
What I care about, is that each click gives me an even decimal increment
that I can control.
The reason for this is as follows:
When I am jogging up to the edge of a job, I eyeball it at 0.01" per click
until I'm close to my gauge block size (I use a 3/4" dia pin in the collet,
and a 0.125 gauge block as a feeler gauge for setting up).
Then I switch to 0.0001" per click and run the pin up until I can just push
the gauge block into the gap.
For this operation I don't care a hoot what the graduations are, so long as
I have a coarse one for rough positioning, and a fine one for twiddling in
the last tenths.
I have another application though, for which the even graduations matter.
Sometimes I'm too lazy to program a drilling job, and I use the CNC as if it
were a DRO equipped manual mill.
I build molds for a living, and there's lots of holes in lots of plates.
I plan the holes to be on even decimal centers as often as I can.
When I'm moving from hole to hole, it's nice to be able to set a coarse
increment, and have each step move an even decimal fraction of the hole
spacing.
I still don't count clicks; what I do is look at the job until I'm close and
then look at the readout to click it into position.
It's really nice if the movement occurs in even chunks so I don't have to
switch between coarse and fine on the pulse generator all the time.
As an example, suppose I want to move between holes that are 5.000" apart.
My first hole happens to be at X0 Y0.
I bomb along to the second hole by eyeball using the 0.01" per click
function, looking at the job and the drill until my drill point is close.
Then I transfer my attention to the readout and keep clicking until the
number says 5.000
I don't care if it took 3 clicks or 4; what I care about, is that when I got
close, it had moved say 4.9600, and not say 4.9612.
That way, I'm not constantly swiching from 0.01 per click to 0.0001 per
click to dial in the holes.
Notice I haven't ever bothered to count the turns or the clicks; I don't
care a fig whether it goes 96 clicks per turn or 100, so long as each click
moves me EXACTLY 0.0100".
So, after all this lengthy dissertation...have I overlooked something that
makes a 100 division encoder mandatory???
All you commercial CNC drivers.... more thoughts anyone?? Are you guys doing
it differently??

Cheers

Marcus

>
> Spehro, this is just about right for the application, except, it MUST
> be 10 or 20 or 50 or 100 detents. One full revolution is important
> and 18 does not convert to any useful scaled units. Is this a $20
> part or a $100 part? Is it available in one of the listed scalable
> numbers?
>
> Best Regards,
>
> Fred Smith
> IMService