On 06/15/2010 10:33 AM, Ignoramus3037 wrote:
On 2010-06-15, Karl wrote:

lid wrote in message
...
Since I fully gutted the cabinet and removed all inside wiring (but
not wires coming from the outside to the huge terminal block), I was
able to test more stuff.

I did test the X-Y servo motors last night by just applying voltage to
their DC leads. They moved nicely. At 30 volts incoming, the X-Y table
moved at about 1 inch per second, and the motors consumed appx. 1.3
amps.

What this tells me is that the mill is not "broken" (no surprise
here), and also that 80 volts and 20 amps total capacity of my power
supply, should be plenty for my light home use hobby purposes.

What I will do, for now, is just make a convenient terminal block on
the outside of the mill, so that I could move X,Y,Z by applying DC
voltage to these terminals.

I will hopefully get to that tonight. Also tonight, I will start
making aluminum adapter plates for the US digital encoders.

The next step would be to connect encoders to Jon's motion controller,
apply voltage to DC motors and see encoder data displayed on the PC.

I will try to spend a long time without hooking up servo drives, to
wire and program as much as possible of safety related stuff (limits,
estop etc). My own hands will be motor controllers, so to speak.

With the encoders working, and hand motor control, this will be
actually a fully working semi-manual mill!

i

Iggy, you're likely to end up like me. I enjoy making old iron better than
new so much that this has become my metalworking hobby. Looks like you're
headed toward a wonderful machine for less than $1K out of pocket.

I think so too.

Now, do you think that I am on the right track with my plan to
implement everything except servo drives first, and wait with servo
drives until everything else has been debugged? Does that make sense?

If you were an experienced engineering team designing NC mills for a
living -- maybe not. You should know enough to do a few preliminary
tests, make some claims based on similarity to previous products, and
smoke test early. OTOH, even in a commercial setting it's not a bad way
to go, and certainly what many teams do after the initial test lets out
too much magic smoke.

Since you're an individual, I think you're on a very good track. Maybe
not the _best_ track, but certainly a very good one.

--
Tim Wescott
Control system and signal processing consulting
www.wescottdesign.com