Re: My CNC Mill retrofit project

Message: 5
Date: Mon, 11 Oct 1999 09:21:23 -0500
From: Ray Henry <rehenry@...>
Subject: Re: My CNC Mill retrofit project


Andrew

It's alive! It's alive! Don't snip ANY wires!

Forgive my impertinence. I've nursed a lot of old machines and I'm fond of
studying their innerds and the long-term effects of the design decisions of
their makers. It never occurred to me to ask if it was alive. If it is,
why do you want to/need to convert it?

[It's alive, but just barely...]

1. If it is short on program memory there are easier ways to overcome that
than a brain transplant. That punch tape input shown on rammill2.gif
should provide a dandy drip feed input. An almost trivial task, if the
machine could be run from tape.

[Punch tape? You've got to be kidding. I suppose it might be possible to
run it on mag tape, but that stuff's prone to errors. And the thing is
really senile- I know that even if I manage to trick it into starting
properly, as soon as I get something going on it , it will crap out
absolutely. I'm interested in running programs that are more than a
megabyte, and I just don't think this old control system will be able to
execute them reliably.]

2. If is has axis control - palsey, overshoot, following error, or looses
it place - problems they won't be cured by a brain transplant. The new
control may help tune down some of these kinds of problems but most likely
they won't go away.

[I don't think this is the problem- I'll have to get it running better to
find out for sure, though.]

3. If the mechanics are sloppy - backlash, way play, worn keyways, loose
belts - a brain transplant may make these symptoms worse because the new
control will likely give the computer a tighter grip on the mechanics.

[The mechanics seem okay, but I haven't run it enough to get much of a
feeling for that stuff.]

4. If it goes belly up once in a while - blank screen, milisecond overlaps,
non operator or program related crashes - these needle in the haystack
kinds of failures can often be traced to aging contacts and aging
capacitors. Some of these may be in the power supplies others in the brain
others in the drives others in the interface circuits and wiring. The
specific nature of these kinds of failures should determine how far you
need to go with the retrofit.

[These are more the sort of problems I've noticed. Lately, it has only
managed to boot up halfway, and won't accept any commands- if it's alive,
it's in a coma.]

BTW Matt mentioned the need for and a source for doccuments on the drives.
Do you have any other diagrams or books on this machine?

Ray

[The two gifs on my page are the only schematics I've got. I've also got an
operator's manual, but it is dedicated to running the control system and
its repertoire of canned routines- there wasn't anything about ripping its
guts out. When I do this, should I send you the old control computer? ]

Andrew Werby

Andrew Werby - United Artworks
Sculpture, Jewelry, and Other Art Stuff
http://unitedartworks.com