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Offline Hood

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Re: Physical buttons for plasma
« Reply #430 on: November 24, 2016, 04:52:24 PM »
The Trafimet electrodes are just straight and seemingly the S series (which mine are) are blowback start as well.
The actual swirl ring is tiny in the Trafimet torch, about 14mm in dia and about 4.5mm thick with an internal dia of about 10mm. The holes I would guess are about 0.6 or 0.8mm in dia and there are 4 of them.


Made some progress with the THC. Denis asked me to video the axis moving under the test routine in the THC and he said it looked like it was using the accel set in motor tuning wher normally with the PP and other controllers it doesn't. To check it out I drastically reduced the accel and sure enough the moves were very slow in accel.
So he suggested I change my Velocity from 5m/min to 2m/min and change the Accel from 1000mm/s/s to 5000mm/s/s and see if it made a difference. It did, THC now is usable, it still jumps around constantly but it is probably under 1mm in total. I will do some more testing tomorrow if I get a chance or the weekend if not.

The plasma is going to be really handy though, today I had to make up a wee box from 4mm Alu, normally I would have hauled out the evolution circular saw and chopped a bit off the sheet, problem with doing that is it is never 100% square. Today I shoved the half sheet up on the plasma, wrote a quick bit of code to run 950mm in X, 180mm in Y then back on the X. Took about 30 seconds to do the cut and it was dead true :)

Think I will have to see if I can manage to do a few wee wizards for simple things like that as although hand coding is not hard it would be much quicker in a wizard.

Offline Hood

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Re: Physical buttons for plasma
« Reply #431 on: November 24, 2016, 04:56:04 PM »
Oh here is the initial THC video I did, as you can see it overshoots badly banging the torch up and down against the Alu.

https://www.youtube.com/watch?v=PqJ2s_2znsQ

Here is the one I did after ajusting the accel and velocity, much improved.
https://www.youtube.com/watch?v=AcdJEg3fL7E

And here is one where I angled the sheet at probably about 20 degrees.
https://www.youtube.com/watch?v=Qo7-F2NGaVY

Offline Davek0974

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Re: Physical buttons for plasma
« Reply #432 on: November 25, 2016, 02:17:02 AM »
There a simple plasma shape wizard on the Mach site, Mach Tool Box, that might help you out :)

When you say it jumps about, i think that may be normal, my one does and its pretty sharp - you can feel the Z moves in the table as there is no acceleration its quite harsh but thats what you need. It takes a long time to tune THC correctly, and even then it can be hit and miss sometimes.
Bridgeport Mill, Mach3 V062, CSMIO-IP/A controller, AC Servo Drives

Offline Davek0974

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Re: Physical buttons for plasma
« Reply #433 on: November 25, 2016, 02:34:55 AM »
Bridgeport Mill, Mach3 V062, CSMIO-IP/A controller, AC Servo Drives

Offline Hood

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Re: Physical buttons for plasma
« Reply #434 on: November 25, 2016, 02:51:36 AM »
Thanks for the info regards the THC, Denis reckoned it still wasn't good enough but for me at least it is usable now. Or maybe I should reserve judgement until I have tested further at different vel etc.

Yes found the shapes last night as I kind of half remembered Terry doing them. Got them altered to suit the code I need spat out, will test it today :)

Offline Davek0974

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Re: Physical buttons for plasma
« Reply #435 on: November 25, 2016, 03:52:36 AM »
On your THC, do you have a start delay - the THC should not kick in until the arc is established & stable on the cut AND the cut motion has started.

The see-sawing you had on vid 1 looks like way too much gain on the Z axis for THC moves, but I am only used to stepper drive THC so maybe your system does not have that?
Bridgeport Mill, Mach3 V062, CSMIO-IP/A controller, AC Servo Drives

Offline Hood

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Re: Physical buttons for plasma
« Reply #436 on: November 25, 2016, 07:14:00 AM »
On your THC, do you have a start delay - the THC should not kick in until the arc is established & stable on the cut AND the cut motion has started.


Yes you can adjust the delay via the display unit.

Quote
The see-sawing you had on vid 1 looks like way too much gain on the Z axis for THC moves, but I am only used to stepper drive THC so maybe your system does not have that?

There are not many settings available in the THC, seemingly they had a deadband setting in their last THC but removed it from this one as they felt it was not needed. It is fine with most controllers and the parallel port as far as I can gather but because the CSMIO doesn't do things the way the PP and others do, ie the instant motion without accel, then there are problems.

Messed abut a bit today, first tried the plate at about 20 or so degrees and it worked ok, not great but just the same as it was on the flat.
First vid on slope, second on flat.
https://www.youtube.com/watch?v=a2g7olaCXFk

https://www.youtube.com/watch?v=Qrd3KReTxb8

Next I dropped the Vel in Mach further, from 2000 down to 1000 and it was definitely better, still not perfect though.
https://www.youtube.com/watch?v=DP-do2UlfCs

Have emailed CS-Lab to see if they could make it work like the PP does and also Denis at MiniTHC is talking with the engineer to see if they can do anything.
At least it is usable now, that is the main thing but obviously I would like it better.

Hood

Offline Davek0974

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Re: Physical buttons for plasma
« Reply #437 on: November 25, 2016, 08:27:35 AM »
Good stuff :)
Bridgeport Mill, Mach3 V062, CSMIO-IP/A controller, AC Servo Drives

Offline Hood

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Re: Physical buttons for plasma
« Reply #438 on: November 26, 2016, 06:57:39 AM »
Well hit a snag, THC was working ok as in the vids above, not perfect but acceptable. Thing is however I was cutting Alu at 3000mm/min so the cut didnt take long. I then used the same code to cut 10mm steel so the feed dropped down to 1000mm/min so the time basically trebled and that is where the problem arose. The servo drive tripped out about 2/3 into the cut with an Motor Thermal Protection error.
What that means is basically the short sharp constant motion was giving the drive/motor fits and the drive shut down to save the motor.

The manual states a few remedies, see pic below. I may try a bigger motor/drive but I think the real solution would be the second remedy in the list, in other words  to have a deadband so that the motor is not constantly moving. To my mind there is no need for it is the voltage is only varying by a small amount.

Does your THC have a deadband setting Dave?

Hood

Offline Hood

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Re: Physical buttons for plasma
« Reply #439 on: November 26, 2016, 07:01:15 AM »
Here is a vid showing the motor moving, midway through I move the camera to the motor and if you look closely on the driven pulley you can see the pulley moving rapidly back and forth, the grub screw holding the pulley in place gives an indication of how fast it is moving.

https://www.youtube.com/watch?v=0mKL5_zVqk8