Re: emco vmc 100

Hi Spencer,

Too bad it's not economical to repair the control. That's an M1
control, right? Even though it was developed back in the mid-
eighties, feature-wise it'll run circles around most of the retrofit
controllers mentioned on this list. Incidently, as far as I know
most of the controller electronics interchange between their small
production machines. Axis drives, etc from lathes can be used in the
mills and vise-versa. If you shop around a little you might find a
dead machine with useable controller cards. Try contacting Fred Vogt
(sp?), he's the west coast Emco guy. He has his finger on the pulse
of the Emco community and may know of dead machines.

Regarding finding a retrofit kit, I don't think there are any made
for the Emco production machines. The small teaching machines like
the cnc5 may have kits available, those are a totally different
animal, though.

The way their closed loop was explained to me, there's an encoder
disk mounted on the ball screw. It has one slot in it. Based on the
programmed feed rate the control calculates the theoretical time
between sensings of that slot. If it senses the slot and the time
interval is not correct the controller errors out. It appears that
missed steps may not be sensed until the screw makes a complete
revolution, but it's still a very workable system.

As to the spindle motor, I believe it's probably a plain DC motor,
not a servo. Emco's other small production machines use plain DC
motors for spindle drive.

good luck,

Doug

--- In CAD_CAM_EDM_DRO@y..., Spencer Chase <spencer@s...> wrote:
> I wrote a while ago about an Emco VMC that I bought. It turned out
to be
> severely damaged and not worth fixing the control unit as parts
costs are
> too high. I might get stuck with it at a reduced cost and am
considering
> converting it to modern controls. This machine had several advanced
> features that I would prefer to not loose but I will consider
anything that
> works. It had a ten tool turret that will probably have to be
controlled
> manually, a variable speed spindle motor that is a dc servo running
on a
> servo amp and closed loop stepper control. I do not know how the
closed
> loop is implemented, if it uses an encoder or if the stepper
current is
> monitored.. I would very much like to keep the closed loop and
would like
> to keep the original steppers as they are massive and well made.
>
> Any recommendations for kits that are available? I would like to
keep as
> many features as possible and would prefer to do as little custom
adapting
> as possible. The mechanical part of this machine is superb and
worth using
> but not if it is going to cost a fortune and take forever to get
working.
>
> Please reply directly to me as well as the group if you have any
> suggestions so we can communicate further without boring the group
with a
> topic of little interest to most of them.
>
> Spencer
>
>
>
> Spencer Chase
> 707-984-8356
> http://www.SpencersErolls.com