Re: My CNC Mill retrofit project

Andrew

I figured it out. This is just like back in grade school when the teacher
baited a hook and cast it into the classroom. I always raised my hand and
got suckered in - until I finally became sullen, non-responsive, and was
labeled MR. (Way back then they didn't have degrees of learning disability)
And all of that happened in first grade.

Your post reminded me of the movies "Lethal Weapon x" where they always
argue and then manage to snip the wrong wire. Time and again I've stared
at machine wiring and wiring diagrams for hours trying to understand a
relatively simple machine failure. (MR strikes again)

To splice in a new machine brain is not a trivial task. But it should be
instructive for all of us if you take the time to sort out and clearly
doccument each step and each decision in the process as you make them.
Have you got enough web space to allow for an on-line running commentary as
you complete this project? I'd be happy to work on some of the pages and
diagrams. I could start by cutting up your .gif's so they could be more
easily viewed.

From the photos and diagrams on you site it looks like a nice little
machine. I'm not familiar with the brand. Is it manual tool change or is
there a tool caroussel and a changer arm?

I just glanced at your wiring diagrams and the power to your old system
looks a bit like this:

1. Three phase 220 volt power.
Into machine through main disconnect and fuses --
to Lovejoy? (spindle oil cooler?)
through reversing starter to knee motor
through starter to flood coolant motor
legs 1 and 3 feed through a line filter to a control transformer
legs 1 and 2 feed a drive transformer through some kind of resistor/relay set

Will you keep it three phase?

Matt figures that you need opto 22 stuff. It looks like there is some
already there. They're shown in the top center of the bottom right photo.

http://www.computersculpture.com/rammill_page.html

It looks like the cards hold four devices each and there are three of them.
Your mill gif shows them between the power supply panel and a row of
control relays. That part of the drawing is laid out the same way the
control box is laid out.

If I'm reading these things right, the photo shows 8 opto devices in place.
The layout shows 10 being used. The schematic shows 11 being used. You
might want to keep the 110 volt wiring (red maybe) from these opto devices
to the relays/contactors that they control in place for a while. Your new
wiring from a parallel port or stg or (?) would go to the input screws on
these boards.

Ray

> From: "Matt Shaver" <mshaver@...>
>Subject: Re: Re: My CNC Mill retrofit project
>
>> [Some people on this list kindly offered to help me decipher the inner
>> workings of my old CNC mill, with a view towards outfitting it with a
>> modern PC-based control system. Accordingly, I've posted some pictures and
>> diagrams on my site: http://www.computersculpture.com/rammill_page.html If
>> that doesn't work, go to the bottom of the index page at
>> www.computersculpture.com and click the link. I eagerly await word on which
>> wires to cut, where to splice in the new ones, and what to leave strictly
>> alone.]
>
>I've had a good look at your stuff and I think you've picked a good retrofit
>candidate. Essentially you'll want to remove the old control computer and its
>wiring up to the relays that control the major I/O items like the spindle,
>coolant, etc. You need to add an Opto 22 rack or some other convenient TTL to
>110Vac level translating circuitry to connect one of the new PC parallel
>ports to your existing relays. As for the servo side of things I think I
>recognize the servo amps as ones made by Servo Dynamics in Chatsworth, CA.
>I'm not 100% sure of this, but you need to look at them carefully and if they
>are from SD then you can call them and get documentation. The servo amps will
>be driven from the D/A outputs of a Servo-To-Go card. I'm assuming the
>machine has conventional encoder feedback (right?). If you want to discuss
>this interactively just give me a call at (410) 521-3715.