Re: [CAD_CAM_EDM_DRO] Thoughts on PC Based Control Retrofit....pictures of the specimen

Marty Escarcega wrote:

> Ok, I made a deal. I need encouragement here. Dan Jon? Anyone?
> Its a Bridgeport Series I. Machine is complete. Looks like hard
> chrome ways in nice shape. Stepper motor drive, limit switches are
> there. I heard the head run sounded good.
>
> Now, here is the question. I want to keep the conversion low buck.

You had better define "low buck". Some guys want to do a complete
retrofit with a 4.77 MHz 8088 PC from 1972, with a cost limit of $150.
Some guys think $5000 is cheap after seeing a machine retrofitted at
work for $30,000.

> spend the money where it makes sense and as I get it. Little at a
> time. I want to go PC based. What will I need to do the conversion?
>
> Anyone done one of these?

Yes, definitely. 1 233 MHz Pentium PC, fully compatible with the
Linux hardware compatibility list, with a floppy, CDROM, 32 MB
of memory, and 2 parallel ports, one of them EPP or ECP capable.

You can use the parallel port directly to drive the stepper drivers, but
I will be coming out with a single board that drives 4 stepper axes, with
optional encoder feedback, for a target price of about $200. I can't guarantee
that price since the last design details aren't worked out yet. This board will
give much smoother velocity ramping, thereby allowing higher feed rates.

You will need to do some significant wiring for the spindle, coolant, and lube,
if it is an electric lube pump. If you don't have 3-phase power, I strongly
suggest one of the newer VFDs. You get variable speed, reversing, dynamic
and DC injection braking, motor overload sensing, the possibility of controlling
spindle speed from the PC, etc. with one of these, as well as single to 3-phase
conversion.

Check out Gecko Drives for stepper drivers. I think you can do all this for a little
over $1000. Don't underestimate all the wire terminals, cables, cable bushings,
relays, etc. All that small stuff adds up.

Jon