Re: [CAD_CAM_EDM_DRO] bridgeport boss conversion questions.

> From: Terry L. Ridder <terrylr@...>
> i have been approached by a machine shop to look
> at the conversion of 4 bridgeport boss mills to
> an alternate control system. the reason being that
> replacing/repairing a boss card has climbed to
> $1500.00 usd.
>
> i met briefly with the owner today and will met with
> him again tomorrow. he has interest in using rt-linux
> and emc for the conversion.
>
> i would be interested in hearing from anyone who has
> attempted a conversion of a bridgeport boss mill.
>
> anyone who could/would be able to point out the
> areas to be especially aware of would also be
> helpful.

I have done this:

http://users.erols.com/mshaver/bps1.htm

Having said that, and even though I'm probably the biggest EMC cheerleader
there is (and anyone who has met me in person will tell you this is true), I
can't recommend that you use the EMC for this project at this time. The
reason is that you won't be able to achieve the 120ipm or 150ipm rapid feed
rates that the machine was originally capable of without some sort of
external hardware to handle generating the step pulses. The EMC doesn't have
a fine enough control of the step pulse frequency at high pulse rates to
accelerate and decelerate the stepper motors to the velocities you need. The
problem is that no external hardware of this type exists today that has been
interfaced to the EMC software. Jon Elson is working on a system of external
hardware modules that will provide this functionality, but this won't be
ready for several months. No matter what system you eventually use for these
retrofits, I would almost unconditionally recommend keeping the existing
Bridgeport axis drive electronics, rather than replacing everything as I did
in the machine featured on the page I referred to above. The only reason I
did what I did is that my machine was already gutted when I got it and there
wasn't enough left to salvage.

If you have a few months to kill before this job needs to be done, then
perhaps you can wait for Jon's hardware to be finished. It might even be
possible to shorten this schedule somewhat given that you would be able to
purchase 4 units immediately, however that would be totally up to Jon. Three
questions:

1. Where are you?

2. Are these machines currently running?

3. Does the customer want to do all of them at once, or does he want to
cannibalize one or two to get the other ones running on their original
controls and then retrofit the donor machines with the new controls?

If you need to do this right away, I can tell you the easiest way to go.
Contact Darrell Gehlsen at:

http://www.machinemaster.com/

He makes a kit to do exactly what you are doing using the Ahha software. You
can easily do one machine each day, maybe all 4 in 3 days. I've installed one
of these kits and it works fine and my customer was happy with the job.
Darrell also provides excellent technical support and I will vouch for his
honesty and integrity. Your cost would be about $2600-$3000 per machine
depending on what you spend for the PCs.
I don't like the software as much as I like the EMC, but that's my personal
opinion. This system will run the machine at it's original feedrates because
the software runs as a single task under DOS, rather than as a real time
process in a multi-tasking environment like the EMC in Linux. As a result of
this difference, the position display doesn't update in real time like the
EMC, and you can't edit a file, play a CD, and surf the internet all
simultaneously while machining a part like you can with the EMC either ;)
Unfortunately, life is full of compromises...

Matt