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Author Topic: Just when you think you are finally getting there....  (Read 5825 times)

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Offline Davek0974

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Just when you think you are finally getting there....
« on: October 23, 2016, 04:50:53 AM »
It kicks you in the wotsits again....

I thought i'd try engraving on the bridgeport conversion today, got a little job coming up, knocked up a simple job - just the word 'Test' in V-Carve, 2mm deep 30deg 0.2mm tool.

Worked fine on my mini-mill before.

Every time it hits line N2230 i get the damn ePid fault and everything stops. :(

I tried 50% feed-rate, no change.

The motion seems very harsh, its lots of little moves but the machine shakes when it does it.

Acceleration too high? It's currently set on 400mm/s/s and speed is 3500mm/min and seems pretty low i think??

I have 0.05mm backlash comp set at 10% speed.

Its been working well up to now.

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

Offline Davek0974

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Re: Just when you think you are finally getting there....
« Reply #1 on: October 23, 2016, 06:16:12 AM »
Well, i lowered the acceleration to 350 and increased the max following error in Pid tuning to 400 from 300 on the X axis - this was the one that was faulting.

Seems to be ok now, it did the test run ok anyway.
Bridgeport Mill, Mach3 V062, CSMIO-IP/A controller, AC Servo Drives
Re: Just when you think you are finally getting there....
« Reply #2 on: October 23, 2016, 06:24:40 AM »
Google search epid cismo turned up a few hits

Here's one, few theories, mach3 version changed fixed it for at least one person...

Cismo problem...https://www.machsupport.com/forum/index.php?topic=29032.0

Tried their support

What versions of everything are you running (m3, cismo plugin, how much ram, graphics card ram (is it dedicated)... seems a long way down the line numbers and strange to always hit at the same place when all they are is x Y motion (no noise induced tasks... spindle speed change, coolant, air, whatever...)
Rob

Albert Einstein ― “If you can't explain it to a six year old, you don't understand it yourself.”

Offline Davek0974

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Re: Just when you think you are finally getting there....
« Reply #3 on: October 23, 2016, 09:02:30 AM »
Running Mach 062, CS_Labs reckon 022 but have been told that one has many other issues that make it not a good choice.

The PC is just a standard Dell Optiplex GX520 no idea on specs but have them running Mach on 3 machines reliably.

Plugin version is the one delivered with system, not sure on ver but dated 27th Jan 2016.

Its the X axis that was faulting, maybe i just had the max following error setting too tight?
Bridgeport Mill, Mach3 V062, CSMIO-IP/A controller, AC Servo Drives
Re: Just when you think you are finally getting there....
« Reply #4 on: October 23, 2016, 09:10:46 AM »
Sorry Dave, can't help more.
Rob

Albert Einstein ― “If you can't explain it to a six year old, you don't understand it yourself.”

Offline Davek0974

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Re: Just when you think you are finally getting there....
« Reply #5 on: October 23, 2016, 09:20:35 AM »
No worries, its working now thats the main thing, it may have just been me being too tight with the settings.

I think the 300 limit i had equates to 0.15mm following error before faulting, too tight for rapid reversals?
Bridgeport Mill, Mach3 V062, CSMIO-IP/A controller, AC Servo Drives
Re: Just when you think you are finally getting there....
« Reply #6 on: October 23, 2016, 10:21:11 AM »
I find its better to start slow and increase both feedrates and not so much spindle speeds, and the smaller the bit size the lower the speed but hey this is teaching old dogs new tricks

regards Ford

Offline Davek0974

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Re: Just when you think you are finally getting there....
« Reply #7 on: November 27, 2016, 06:41:32 AM »
Ok, so what's not right here?

Cut some 5mm Alu on the high-speed spindle yesterday and it looked ok i thought, confidence was restored :)

Went out and did another part today, same file, but results looked poor and scrutinising yesterdays work closer it seems the fault was there too but not quite as pronounced.

it looks like the toolpath on the finish cut is pulling away from the corners too soon - corner rounding??

The finish tool is a 2mm single flute carbide at 23000rpm, 1000mm/min feed.

Not sure why todays was worse than yesterday although the machine was slightly warmer yesterday as this was the second job run.

Great care was taken when doing the CAD&CAM to get the tool right into that corner to give a 1mm radius

The surface is actually smooth - the rough look is swarf stuck with cutting fluid;)

I did do some major servo tuning but have not altered speeds or acceleration in motor tuning.

What could do this, any suggestions?
These parts need to be accurate :)
« Last Edit: November 27, 2016, 06:43:16 AM by Davek0974 »
Bridgeport Mill, Mach3 V062, CSMIO-IP/A controller, AC Servo Drives

Offline mc

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Re: Just when you think you are finally getting there....
« Reply #8 on: November 27, 2016, 07:43:42 AM »
I'm going to guess that's around where the axis speeds starts/finishes changing speed for/after the corner?
Re: Just when you think you are finally getting there....
« Reply #9 on: November 27, 2016, 07:44:30 AM »
What acceleration are you using?

The problem with mach3 is the CV mode tradjectory following is not tunable.... Like it is in some if the newer cnc software
Rob

Albert Einstein ― “If you can't explain it to a six year old, you don't understand it yourself.”