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Author Topic: Bridgeport Knee Mill Conversion?  (Read 159165 times)

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Offline Davek0974

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Re: Bridgeport Knee Mill Conversion?
« Reply #560 on: October 08, 2016, 05:37:06 AM »
got the encoder fitted, anyone know what settings i need to activate in the system to close the loop?

I tried activating the pid loop in mach and it makes the speed oscillate wildly so i turned that off again for the moment.

in the picture attached, i have now activated "Spindle DAC" as without it there was no speed control at all but is that enough, do i need more stuff set here?

Any tips????
Bridgeport Mill, Mach3 V062, CSMIO-IP/A controller, AC Servo Drives

Offline mc

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Re: Bridgeport Knee Mill Conversion?
« Reply #561 on: October 08, 2016, 05:56:42 AM »
You generally need a lot of damping to run closed loop with a VFD, as they are usually very slow to respond in comparison to a servo drive. Try dropping P to near zero, and I&D to zero as a starting point. Personally, as you're running direct drive, I'd be inclined to leave it running open loop, as the VFD itself will maintain near constant speed.

Regarding your G28 issue, have you got an example of the code?
If the post processor is inserting a co-ordinate as part of the G28, it could well be causing a move outwith machine limits. Have a read of this article - http://www.cnccookbook.com/CCCNCGCodeG28ReturntoReference.htm

Offline Davek0974

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Re: Bridgeport Knee Mill Conversion?
« Reply #562 on: October 08, 2016, 06:04:28 AM »
Thanks, i'll have a play with the pid values.
If running open-loop, do i need the encoder at all, can't remember now what function it performs ??

The code was just G28 G91 Z0.

I'll read the link later.
Bridgeport Mill, Mach3 V062, CSMIO-IP/A controller, AC Servo Drives

Offline Davek0974

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Re: Bridgeport Knee Mill Conversion?
« Reply #563 on: October 08, 2016, 07:22:50 AM »
After hitting the problem with both G28 and G53 moves I switched to single block and stepped it, it triggered at the M6 command.

Next i pulled the M6macros out and it worked ok, a coffee and a sit-down with the macro open showed the problem. It was connected with the screen-set and the M6Start macro, a variable and DRO called "Clearance Plane" - this is used in the 2010 screen-set tool-change routines.

But as I cannot use them on the Bridgeport and do not need them due to the fixed length tooling, the already edited M6Start macro was still using the values and trying to send the Z to a position beyond home when triggered.

This is why the code always ran fine as a single-tool job - the first line in the M6Start skips the routine if the current tool = selected tool so the dodgy code was never hit :)

I have now edited the M6Start to remove all references to clearance planes, offsets etc and just issue a straight G53 G0 Z0 style home move.

The code i was struggling with has now been air-cut 6 times with 100% success.

Thanks for all the tips.


Now, back to "what is my encoder actually doing???"   :)
Bridgeport Mill, Mach3 V062, CSMIO-IP/A controller, AC Servo Drives

Offline Hood

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Re: Bridgeport Knee Mill Conversion?
« Reply #564 on: October 08, 2016, 08:08:33 AM »
Good you got it sussed :)

Encoder gives spindle speed reading in Mill and also more importantly allows rigid tapping :)

If I recall for true spindle speed reading with the IP-A/S you need to make sure the Averaging is disabled in Ports and Pins.

Hood

Offline Davek0974

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Re: Bridgeport Knee Mill Conversion?
« Reply #565 on: October 09, 2016, 10:00:21 AM »

Encoder gives spindle speed reading in Mill and also more importantly allows rigid tapping :)

If I recall for true spindle speed reading with the IP-A/S you need to make sure the Averaging is disabled in Ports and Pins.

Hood

Ok, I have spindle-speed averaging off, closed loop spindle control off, use spindle feedback in sync modes on.

There is no change in speed displayed, BUT does it need a certain DRO to view real speed?

The 2010 screen-set uses DRO 202 - "Overridden spindle speed" only - this just seems to show requested speed, i would expect an actual-speed display to show some variance when running??

Maybe it needs DRO 39 - true spindle speed instead - i can easily swap them over i guess if thats the one?

Did some more cutting today, just modifying my vise jaws for a job coming up, deliberately took some fairly heavy cuts on a 20mm tool down at 500rpm and the new drive setup didn't even notice :)
« Last Edit: October 09, 2016, 10:06:58 AM by Davek0974 »
Bridgeport Mill, Mach3 V062, CSMIO-IP/A controller, AC Servo Drives

Offline Hood

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Re: Bridgeport Knee Mill Conversion?
« Reply #566 on: October 09, 2016, 11:17:07 AM »
Yes, OEM 39 is correct.

Good news about the VFD :)
Hood

Offline Davek0974

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Re: Bridgeport Knee Mill Conversion?
« Reply #567 on: October 09, 2016, 11:26:42 AM »
Great, will tweak the screen-set and try again.

Yes the vfd/motor setup seems well matched and didn't even notice the cut :)

I think the project is just about done now - checked the high-speed spindle setup again yesterday and that is all set now, needed a wiring change due to changing the vfd for the main spindle - the safety relays are different.

How do i verify if the encoder setup really is ready for rigid tapping?
Bridgeport Mill, Mach3 V062, CSMIO-IP/A controller, AC Servo Drives

Offline Hood

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Re: Bridgeport Knee Mill Conversion?
« Reply #568 on: October 09, 2016, 01:23:36 PM »
Just download the plugin and place it in your macro folder (Version 2 is best option I think).
http://www.cs-lab.eu/en/artykul-110-NEW__threading_macros__two_versions_decription.html

Zero the Z axis at a safe point and then MDI the following
G0Z5

M84 Q-20 P1.5 S200 R400

The M84 line will  go to z-20 with rpm of 200 at 1.5mm/rev and then will retract at 400rpm at 1.5mm per rev.

Not sure if your spindle needs to be turning initially or not as I don't think I have ever used it without the spindle on prior to calling a M84


Hood

Offline Davek0974

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Re: Bridgeport Knee Mill Conversion?
« Reply #569 on: October 09, 2016, 02:21:17 PM »
Thanks Hood, will test that.
 :)

Is there any indicator to look for to show things are or are not set right?
« Last Edit: October 09, 2016, 02:24:58 PM by Davek0974 »
Bridgeport Mill, Mach3 V062, CSMIO-IP/A controller, AC Servo Drives