Mach controlled spindle

[krymis]

what do you have to replace to get mach to fully control the spindle of an x2? I want to control the direction of the spindle and the speed of which it spins. Would I have to replace the motor with a servo, encoder, and a gecko or something?

[The Blight]

There are a couple cards out there that will do this for you.

http://www.cnc4pc.com/ has one. It's the C6, and Hoss is using one.
http://homanndesigns.com/store/ Also has a couple speed controller cards. I bought 2 of the digispeed XL cards. Havn't tested them yet, but I hope to do so soon.

[krymis]

i looked at those. I have the c11 board with that card built in. As i understand it you cannot control the reverse of the spindle. Not that it is that important. But i have also heard that the speed card from cnc4pc is half hit or miss. Just trying to find a good way to do it.

[The Blight]

Reverse the spindle? well you can do that with the Digispeed card. Or else you will need to wire up a relay connected to the CCW command.

[fatal-exception]

Servo motor + gecko works great for the spindle.

I'll never go back to manual on/off.

[krymis]

can you give me any more info on what motor you used and how you wired it up? Did you set it up in mach with an extra axis or can you just run it from the spindle setup in mach.

[fatal-exception]

Sure. I used a keiling 900ozin servo motor, Gecko g320 driver, us digital 100cpr encoder, 72vdc power supply. Max speed of the servo motor is about 3000rpm. (the PS only gives out 68vdc, I don't know why) I've geared it up to give me about 5000 at the tool.

You could probably get away with a coarser encoder. I just used the regular spindle setup in Mach3. It's trial and error to get the 'steps/per' setting right so that when you tell it to turn at 3000rpm, it does turn at 3000rpm, but that's pretty minor. Using some additional feedback sensor would simplify the process since you can then use the auto spindle calibration.

It would be simple to switch the spindle to a real axis for coordinated spindle motion. I havent tried it yet, but plan to this weekend to do some threading on some short parts I can hold in a collet.

One nice thing is that the spindle speed remains constant when cutting...

Paul

[krymis]

paul,

what do you mean by using the additional feedback sensors? What would they be and where could you get them?

[fatal-exception]

Photo-reflective sensor, 1 pulse per rev. Everyone sells them.

[cadmonkey]

Originally Posted by fatal-exception Photo-reflective sensor, 1 pulse per rev. Everyone sells them.

EVERYONE?!? : Just kidding - you can also pick up an optical interrupter and make a disk with as many slots as you want (more slots = better resolution if Mach allows multiple pulses per rev like a shaft encoder)

I picked up a dozen of these http://search.digikey.com/scripts/Dk...name=H21LTB-ND and am using them for limit, home and index pulses on my X3.

Good luck.

[ozzie34231]

Cadmonkey:
Really glad to see your source. Please post your wiring of these; not necessarily the connection to Mach for all the possibilities, just the power in, resistors, and signal out. I'm electronically handicapped and the spec drawings don't mean anything to me. If you can give me + and - 5v, this value resistor here, and signal out here, I'd be grateful.
Ozzie

[cadmonkey]

A simple schematic. These are pretty failsafe - if the supply voltage dies, the output will too stopping the mill. If wire breaks, same. Yet each one can be wired independently. So you can have a separate max limit, min limit, home limit, etc. You'll probably need an extra LPT card but for $20 it's worth it. The switches are all opto coupled so as long as you put a reasonable fuse (say 1A) on the logic line from your PC's 5V power supply out to these, you won't blow anything up.