General questions about a spindle of a CNC-mill

On my job we are developing an automated vice that is meant to automate the vice of older CNC-milling machines. To open or close the vice, we want to us an tool that is being clamped in an Er-collet in a spindle (see concept drawing in the attachments).

In order to make the concept work, we have the flowing generals questions about spindels of an CNC-milling machine.

1. Can the torque of a spindle be read and adjusted to an specific input value (while in operation)?
2. Can the torque stop rotating when a specific input value is reached?
3. What is the minimal rpm that a spindle can rotate?
4. Is it possible to give the spindel the instruction to rotate 10 rotations. If the 10 rotations are reached can the spindel stop rotating after that?

Many tanks in advance for taking the time to answer the questions!

Your drawing didn't come through, but I think I get the idea.

re 1 - no spindle I know of can act like a torque wrench - so no to number 1 so far as I know
re 2 - same as #1 - typically not
re 3 - depends on the spindle - I think mine all have minimums somewhere in the 100 rpm range, though might go down to 50. But none of them have much torque there.
re 4 - sort of - if the machine has rigid tapping, it has a fundamental mechanism close to what you seem to be looking for.

Every installation of automatic vises I've ever seen, be it trade show, shops, videos, etc, used a separate pneumatic or hydraulic system which the control activated. (An "m code" for "engage vise" sort of thing.)
Barring that, hydraulic or pneumatic valve activated by a tool could work (tool held by either mill or robot.)

However, if you are doing a retrofit, what you likely need is a torque limiting gearbox to drive the vise, most likely a right angle gear as part of it, and then an ER collet holding a tool could tighten it.

Expect it to be fiddly to set up.

Could you mount your tool in an adjustable torque tapping head?

reloaded said:

air 10 chars

Click to expand...

And that air still smells of dead cat.

machtool said:

And that air still smells of dead cat.

Click to expand...

Nah, I think he's gipsy_chips this time around.

Booze Daily said:

Nah, I think he's gipsy_chips this time around.

Click to expand...

Hello Booze,
He's gone as gipsy_chips and is back as reloaded.

To Phil, aka machtool:
Your Message Bank is full

Regards,

Bill

If you went this way, I think a slip clutch would be your torque control method best choice.
FYI, The spindle load is usually shown on a meter or screen somewhere, but actually getting access to that parameter and setting or reading it I think is in the Hard pile.

You could use a tapping cycle to rotate a specific number of times. You would want to make sure your socket had some z axis travel. So you would set the tapping rpm, then a depth and a very small pitch. You could program a thread .02" deep, with a .001" pitch which would give you 20 revs. BUT then it would want to reverse back out! I don't know how to have it not do that.

There is a youtube video where a guy was turning parts in his mill spindle with the lathe tool in the vise. After a few parts it would position over to a different vise that had the ER32 nut wrench in it. it would loosen the nut so more material would fall then tighten it back up.He used the spindle load meter to figure out a torque setting exactly like you want. Ill try to find the video later.

FutureDV said:

On my job we are developing an automated vice that is meant to automate the vice of older CNC-milling machines. To open or close the vice, we want to us an tool that is being clamped in an Er-collet in a spindle (see concept drawing in the attachments).

In order to make the concept work, we have the flowing generals questions about spindels of an CNC-milling machine.

1. Can the torque of a spindle be read and adjusted to an specific input value (while in operation)?
2. Can the torque stop rotating when a specific input value is reached?
3. What is the minimal rpm that a spindle can rotate?
4. Is it possible to give the spindel the instruction to rotate 10 rotations. If the 10 rotations are reached can the spindel stop rotating after that?

Many tanks in advance for taking the time to answer the questions!

Click to expand...

I can't visualize the setup on how you'd connect to the vise in the typical orientation you'd have in a VMC.

I think you might be better off with a mechanical linkage on a bespoke fixture, such as would be used to lock an overcenter clutch. You'd then push and pull on the 'knee' of the linkage to actuate the lock. You'd have lots of Z axis power to do that with.

here it is.

Automatically open and close a collet chuck with your CNC mill to use it as lathe - YouTube

Most CNC controls have the ability to monitor torque of the spindle. Many machine builders use that information as part of tool life/ tool condition monitoring. Any other uses of it would depend greatly on what provisions the machine builder made.