What is wanted in a controller, was Re: Correct or Max voltage for Bridgeport Nema 42? + more...

Alan,
I suspect you are correct that hobby controls wont reach this
complexity. I used this VMC as a model of what semi-modern CNC
controls look like. Keep in mind though that 90 percent of those are
buttons that a standard PC keyboard would take care of. If you wanted
to be really trick, there are flat programmable keypads for point of
sale that you could mount directly to the face of a pendant for
around 150 bux (you print out a top cover that goes over the whole
keypad, laminated it and program the buttons below your symbols or
custom printed keys) I have two of these I hope to incorporate into a
custom control. There are probably 8 or so actual contact type
buttons on that machine and a few of those could go the the PC as
well. The major input devices that should be physical are the jog
wheel (remember that most of the controls have this and it would be
best to make it reusable in the new control), feed rate overide, and
the number one....toolchanger (which actually isn't a button but a
series of I/O events).
There are so many different configurations and therefore it has to be
up to the individual to create their own circuits and control panels
to suit their machine and how complex they wish to get, but $100
worth of Radio Shack switchs, pots, and relays would go a long way.

So I'll probably forget a couple but...

coolant (1)relay
Mist (1)relay
doors (1)switch
Spindle enable (1) relay
Machine start (1) relay
E-stop (1)switch
Toolchanger (2, possible stepper, possible servo, posible encoder).
Jog wheel (encoder....possibly mouse encoder adaptable but true jog
wheels index or "click" to represent 1 step of the jog increment)
Handwheel (for manual style milling from a CNC) possible use of a
mouse style encoder for this
Powerfeeds (also for manual milling on a CNC). There exists a very
cool Knee mill called a Bridgeport R1 C3 which is similar to a BOSS
but has a Heidenhein control and both a handwheel and levers that act
as powerfeeds. You simply dial in the feedrate for the levers and
when you push it in the direction you want, the table moves that way.
There are two levers. One is on the Quill housing and moves only up
and down, the other is on the front of the table and moves up and
down for Y and left/right for X axis travel. Each lever has a button
on the top which you press for rapid travel over-ride of the feedrate.
This is a VERY cool machine. The only thing it lacks is actual
physical feedback (resistance) on the handwheel, but otherwise
combines great manual features with great CNC features. Not including
the rapid buttons, this would entail 6 switches somehow rigged or
built into two levers or joysticks. (unlike joysticks however, you
cannot move X and Y simultaineously (as it should be for powerfeeds).

Air pressure switch (1) switch. This is dire for machines that use
air pressure as a counter balance for the spindle. Severe damage can
result if the spindle drops (actually the whole axis drops).

Spindle speed control (1) DAC

Tachometer (not sure) Camtronics advertises an optical tach for about
60 bux. Some older machines use air to drive varispeed pulleys to
change the spindle speed. That actual activator is electric though.
(electric switch activates air solenoid to physically reposition
pulleys) The Bridgeport BOSS works like this. Others use electrically
operated mechanisms to accomplish the same thing. Both could be
controlled via two relays if the program could accept tachometer
feedback to know when to stop. That's more down the electronic wiz
road then I care to go, but would be an inexpensive alterative to a
spindle drive or VFD to accomplish constant surface speed without
standing there changing speeds manually. (Remember, the same tool can
do a lot of different stuff before you have to change it...some of
those things require different speeds)

Ok, that seems like a bunch but a kind soul from this board pointed
me at this...
http://www.bsof.com/r101prod.htm
Which should be enough for your relays. Switches could be handled (I
guess) by an additional LPT or a motion control board with more I/O.
That bsof.com site has some neat rigs.
dac could also be handled by a motion card.

If you had enough relays and you wanted to get really trick you could
also do things like hook up the flashing warning lights that go on
when you start a cycle...etc.

Although covered in many apps, tool offsets and compensation become
more important when you have a toolchanger. The program has to know
what tool is in each position and operate the cycle.
The toolchanger is perhaps the most complicated of all of this. I
will get into one and see if I can get back to you on the internal
workings of it.
Still, it seems like the hard part has been done. All of this merely
amounts to a very flexible I/O and some custom macro ability added to
what is already out there. We're not talking about pre-fab stuff
here, just the ability for people to wire this switch, or that relay
into their system and have it do something. Basically the easiest
part of what the hobbiests already do ( I mean they are making custom
mounts for their servo's and linear slide tables already, they could
handle some basic wiring). In reality, you tear apart a CNC and it's
really a whole bunch of switches (mostly magnetic), but for sure
there's more than 4 to consider.

Here is an example of an outdated controller (which obviously was
pulled)
http://cgi.ebay.com/aw-cgi/eBayISAPI.dll?ViewItem&item=1703765502

and some machines that could be retrofit candidates...
http://cgi.ebay.com/aw-cgi/eBayISAPI.dll?ViewItem&item=1703318626

http://cgi.ebay.com/aw-cgi/eBayISAPI.dll?
ViewItem&item=1701057038&r=0&t=0&showTutorial=0&ed=1013482363&indexURL
=0&rd=1

The two mills I pointed to could probably be well served by the basic
3 axis motion control and 4 inputs, although spindle speed control,
and the handwheel/powerfeed levers would greatly increase their
usefulness over even their factory new state by providing manual
control. Especially because many people don't have the space for a
manual machine and a CNC machine.
If you keep an eye out on that eBay page (search for CNC) you will
see a miriad of older machines that could be born again with the
right control.

Sean


-- In CAD_CAM_EDM_DRO@y..., Alan Marconett KM6VV <KM6VV@a...> wrote:

> Hi Sean,
>
> Yeah, I replied to Carlos, missed your name somehow! Thanks for the
> reply!
>
> The URL to the 12K machine was impressive! Our hobby controller
> programs are probably not going to get there!
>
> As a hardware/software engineer, I know how to get to complex

controls.

> Yes, a "custom" control panel could be built. Or a pendent could be
> built. But at what cost? I made one with a panel shaft encoder,

and

> two push buttons. Allows jogging in any axis, and rotates through

jog

> sizes. Useful?
>
>