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Author Topic: Rigid Tapping  (Read 25056 times)

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Offline Dom

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Rigid Tapping
« on: March 05, 2010, 05:39:07 AM »
Does mach 3 support rigid tapping and if so what features must I enable in the configuration and also what do I need in terms of hardware/electronics to make it possible ?

Offline Hood

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Re: Rigid Tapping
« Reply #1 on: March 05, 2010, 05:47:02 AM »
Short answer is no.
You can however do rigid tapping if you have a servo or stepper as a spindle, you would then use SwapAxis to swap the spindle to an A axis and programme that way.
 A lot of people do semi rigid tapping using a floating holder.
Hood

Offline SScnc

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Re: Rigid Tapping
« Reply #2 on: March 05, 2010, 01:10:13 PM »
What do you mean exactly by "SwapAxis?"

Offline Hood

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Re: Rigid Tapping
« Reply #3 on: March 05, 2010, 01:39:25 PM »
If you have a Servo for a spindle you can set up an A axis in ports and pins and then have a macro to swap the A axis for the spindle. That will mean that when you command an A axis move it will actually send pulses out to the spindle. Because the spindle is now getting treated as an axis the moves will be in sync between A and Z so you can rigid tap.
Hood

Offline Dom

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Re: Rigid Tapping
« Reply #4 on: March 05, 2010, 07:15:38 PM »
I was under the impression that if you added an optical sensor to count spindle rotations then mach3 would rigid tap, however if you say thats not the case I'll accept that I was misinformed. However the question remains if mach3 cant rigid tap would I need or want a sensor to count spindle revs at all ? Is it necessary to have one to tap with a floating tapping holder or would the sole benefit be just to get an rpm readout on screen in mach ?

Offline Hood

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Re: Rigid Tapping
« Reply #5 on: March 05, 2010, 07:31:50 PM »
In Mill the Index pulse is used to read RPM, not sure but possibly  closed loop VFD spindle control may also use it although I am unsure how good that is. If you use G95 (Feed per rev) on mill then you would need the Index for RPM, most use feed per minute on a mill though.
On a lathe the Index pulse is needed for threading as well as for G95, G95 is normally the mode you would use on a lathe.

If using a floating holder to tap, whether mill or lathe then it would still be a good idea to have a RPM readout as it will help with your calculations for the code..
Hood
Re: Rigid Tapping
« Reply #6 on: March 06, 2010, 03:41:53 AM »
Dom

The problem with rigid tapping lies with slowing down to zero, reversing and coming back out maintaining position

This is doable with a servo motor but there is probably a reason Mach cant do the threading cycle

Phil
The Good Thing About Mach3, Is It's very Configurable

The Bad Thing About Mach3, Is It's Too Configurable
Re: Rigid Tapping
« Reply #7 on: January 04, 2014, 12:36:16 AM »
This guy claims to be doing it with a servo spindle and not using swap axis.

http://www.youtube.com/watch?v=19aSV9JeU10

Offline Hood

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Re: Rigid Tapping
« Reply #8 on: January 04, 2014, 03:31:39 AM »
He is not using swap axis but he is just setting Mach up to have the C axis  with the same pins as he has for the spindle. So as long as he doesnt call a RPM at the same time as he calls the C axis he is fine. So basically he is doing a swapaxis() without doing the actual swapping and with none of the safety features of the swapaxis() ;)

There are a few motion controllers that support rigid tapping, one is the kFlop and another is the CSMIO/IP-S and also the IP-A. I use the IP-A on the Chiron and it does an excellent job of rigid tapping, even peck tapping.
http://www.youtube.com/watch?v=d87kv3GSqvY
Hood

Offline BR549

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Re: Rigid Tapping
« Reply #9 on: January 04, 2014, 01:14:57 PM »
Yes but so far NONE have done RT with a VFD ,encoder setup. Hoods setup uses a servo spindle on the CHinron.

With a servo spindle(expensive) you can simply use 2 sets of specs on the spindle axis( Spindle/C) and call the one you need.

The spindle will NOT get confused this way as  it just does whatever you tell it to do.

Mach3 cannot do RT (VFD/encoder) from the LPT version because it is a buffered system. To do true RT from a VFD/encoder it has to run LIVE in realtime.

With a VFD and Braking resistors you can get very good control with SRT (semi rigid tapping) with a floating tool holder. With the VFD using braking and DC injection you can stop the spindle very quickly on the down stroke.  Use the G84 cycle with this and you have a very good SRT system. I have even used it to do blind holes.

The G95 does NOT work well in Mill when trying to use an index signal. It does work well without using the index signal to sync the feeds.  Mach cannot track the signal through a spindle start /restart. It will crash your G84 cycle every time.



Just a thought, (;-) TP
« Last Edit: January 04, 2014, 01:17:48 PM by BR549 »