Re: [CAD_CAM_EDM_DRO] Re: Rotary to linear translation - an interesting idea.

After all these comments about the Linear DRO I like to suggest the following although I have no need for one for the moment.
There is really nothing new or original about my suggestion, there are pieces from many suggestions put together.

The thin wire has worried me as being delicate and how to prevent slippage and so on. The ribbon sounded better but I think a
rod or a large diameter wire (100 mils or more) is better. I am thinking about 1/4" rod or more. It can be mounted rigidly
and it is not delicate. It would be very easy to seal it well and keep out all the dirt and liquid from the encoder housing
using commercial or home made shaft seals. The rod would go straight through the box.

I would put the encoder wheel in straight contact with the rod and use a single ball bearing as a backup pressure generator. It
would be mounted to give a fixed pre-load through either flexing of the mount or separately spring loaded. The wheel should be
as hard as possible to avoid microscopic changes in compression and to be as wear resistant as possible. There would be no
adjustments and the electronics would be in the same sealed box.

When the DRO output is feed to a CNC controller, it does not care about an "even" count, just a calibration constant. There
would be nothing to adjust and the only thing that could wear is the wheel of the shaft encoder.

For use just a DRO, the calibration would be done in software and at the same time it could switch between metric/English units.

Bertho Boman