Linuxcnc plasma rotary

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05 Jun 2019 10:36 - 05 Jun 2019 10:43 #135925 by Grotius
This is information to set up Plasma Rotary cutting.

Attached a modified post processor for sheetcam rotary. Rename the file extension from txt to scpost.

1. This postprocessor does not use a touch off or probe function. Probing for tube cutting is not a better option in practical way.
(In my case probing can be activated by selecting a gui screen button, this will trigger the THC2 component probe function, but i don't use probing when cutting tubes.)

2. It uses G64P0.05 for optimal accuracy during cutting.
(G64P0.01 up to G64P0.04 will result in bad rotation movement's (shocking) during corner rotation when cutting square tubes)

3. It set's the plasma power "S" in the g-code when a laser tool is used.

4. important : the Z axis zero point is located at center point of the main chuck. When zeroing your z axis on top of the profile, for example a square tube 100x100mm your z axis is at 50mm when on top of the profile, the z-axis value (50mm) can be included the cutting distance about 3-4mm, no problem.

5. Included is a 100x100mm draftsight dxf template file (flatten tube layout) that correspondent's with the sheetcam square tube layout 100x100mm, corner radius 5mm.

6. Attached picture is the output in linuxcnc. In this example you see probe was used. The probe has offset the actual cutting pat'h a little.


7. Example g-code output
Warning: Spoiler! [ Click to expand ]


8. The ini file example for a rotary axis setup, in my case axis B. I changed Lineair to Angular. But without changing this,
it work's also. Wrapping the axis does not improve anything in my case.
Warning: Spoiler! [ Click to expand ]


9. For long tube cutters you need the main chuck driven and the back end chuck driven synchroon to prevent torsing the profile.
For this option you have to modify the ini file and the post processor to adapt a extra axis.

10. Test machine for this config. It's a watertable based on-side rotary cutter.


I hope this info is usefull for our community.
Attachments:
Last edit: 05 Jun 2019 10:43 by Grotius.
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05 Jun 2019 13:24 #135940 by pl7i92
Replied by pl7i92 on topic Linuxcnc plasma rotary
nice mashine setup
thank you
the sheetcam got a module that got tube sqare and Round in Full version witch handeles the Linuxcnc Thcud component

it the post you addet different then the standard sheetcam linuxcnc_rotary
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05 Jun 2019 14:58 - 05 Jun 2019 17:32 #135947 by Grotius
Replied by Grotius on topic Linuxcnc plasma rotary
Hi Maximilian,

nice machine setup
The customer requested a rotary axis. Normally it's a dry rotary axis. But his wish was a rotary water table. So i made some
extra work for the same price !!! Customer is happy.

the sheetcam got a module that got tube sqare and Round in Full version witch handeles the Linuxcnc Thcud component

Yes and no for the THCud component, see item 2 below for the rotary plugin :

sheetcam.com/Register/purchase
1. SheetCam TNG (£110.00)
2. Rotary pipe cutting (Receive a £5 discount if you purchase this with SheetCam)

Total : $217.43 US dollars

Thcud component
For tube cutting you don't really need torch height control. So if we look into the THCud source code :
( in my case the torch height control is fully functional, see comment's below of i/o stream )
Warning: Spoiler! [ Click to expand ]


I look at the THCud source code, i mention that this code is not very usefull for a rotary plasma machine.

What is useful is to connect in hal your plasma arc oke signal of the plasma inverter to motion.feed-hold-inhibited.
This would be the most simple succesfull solution rotary cutter machine.

This day's there are several component's designed, like in progress the plasmac or my THC2-ehtercat component wich is done and has many in and output's, to have a look in the i/o stream :

Warning: Spoiler! [ Click to expand ]


is the post you added different then the standard sheetcam linuxcnc_rotary

Yes, it's different. The one i provided can also be used for :

1. oxy-fuel on rotary axis, it has preheat function's during processing.
2. In my first post i commented about it also set's the plasma power of the inverter.
3. It also can use a second torch head, and offset's for the second torch head are provided as x,y and z scriber value's.
4. And more options like better accuracy, and trough experience no height problem's after cutting many profile parts.

The provided post processor is a very good alternative for the standard LinuxCNC plasma rotatif post processor, which is standard included by the default sheetcam install. The provided post processor is used for over year's and has cut more then 50km of pipe and profiles over the last years. I cutted about 10km of pipe with this processor, to give you an idea. ;)

Without the GPL2 licence Linuxcnc would be less and less powerfull as today's Linuxcnc power is very, very high, top level, high end solution's can be made without problem's. No window's pc can compare with linux at this day's. It's the same vision as Elon Musk and Linus Torvalds and many other's, like the custom linux user's all over the world.

We collect and share info, data and provide example's, give code back, just as the GPL2 licence is intended for.
The extra added line's in the post processor are good to be provided as GPL2 based lines.

A quote from Elvis : " time can do so much "

Last edit: 05 Jun 2019 17:32 by Grotius.

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05 Jun 2019 23:37 #135986 by tommylight
Replied by tommylight on topic Linuxcnc plasma rotary
@Grotius
Your machines look much better than mine!
Good job and thank you.
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06 Jun 2019 13:09 #136039 by BigJohnT
Replied by BigJohnT on topic Linuxcnc plasma rotary
Indeed that is a very nice machine!

JT
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08 Jun 2019 21:14 - 08 Jun 2019 21:23 #136307 by Grotius
Replied by Grotius on topic Linuxcnc plasma rotary
Thanks for the compliment's.

I was testing the postprocesor for a while and i see 2-3 tiny thing's that has to be solved.

1. M30 has to be changed to M2.
2. Sheetcam has a little bug at the second last line of the g-code, not very important. Will compare some output code monday.
It only appear's when you don't cut off the profile, but the last cut is a circle cut. Then it prompt to forget a M5 when moving away.
3. G64P0.01 is accurate enough for sheet cutting, for tube cutting G64P0.05 is not accurate enough at some perpendiculair moves. I have too look how to solve this, I only need the G64P0.05 to ensure a acceptable rotary speed with the torch moving handshake, problem appear's only when cutting big profiles on the rotary. I hope to solve this monday.
Last edit: 08 Jun 2019 21:23 by Grotius.

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08 Jun 2019 23:46 #136316 by tommylight
Replied by tommylight on topic Linuxcnc plasma rotary
Are you using the THC to follow the contour of square tubing or from gcode output of sheetcam driving Z axis without THC?
Did some experimenting a while back with a fast Z axis and a Prima THC, it did work quite good, but noticed that on the way down the torch would lag a bit meaning to high from the tube, but the cut was OK. This was with max. 50X50mm square tubing, did not need more so did not try but I doubt it would work as the slope becomes to much for the THC to follow. Also this was with only one moving axis, so the torch was moving only in one axis and Z height.
I am aware that having both axis X and Y moving and using a post processor is much better and can cut any size the machine can handle, but I did not have the post processor and lacked time.
Thanks for the info.
BTW, the last rotary I built had only probing with no THC as it was only for round tubing. Ended up pretty cheap and the client is extremely happy with it. Also looked nicer than the rest of my machines. I did post pictures and videos here I think.......or did I???

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09 Jun 2019 20:16 - 09 Jun 2019 20:19 #136400 by Grotius
Replied by Grotius on topic Linuxcnc plasma rotary
@Tommy,

Are you using the THC to follow the contour of square tubing or from gcode output of sheetcam driving Z axis without THC?
In my case we can do both option's. It will execute the movement's based on gcode. When activating the torch height control
it will do correction's based on torch volt control. The torch volt control is based on the integrated Exernal Offset branche.

Did some experimenting a while back with a fast Z axis and a Proma THC, it did work quite good, but noticed that on the way down the torch would lag a bit meaning to high from the tube,
Users can use the Probe function if they want to. Optimizing the switch offset value output's in a perfect start height. But i prefer to not use the probe function for tube cutters.

I did post pictures and videos here I think.......or did I???
Yes, you did post pictures of your tube cutter application.

Additional info for tube cutters in linux.

The negative adaptive feed result's in a very simple restart procedure, done by the component. In my case the THC2 component designed for sheet metal cutters works even so good for a tube cutter i mentioned.
Last edit: 09 Jun 2019 20:19 by Grotius.
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09 Jun 2019 23:32 #136423 by tommylight
Replied by tommylight on topic Linuxcnc plasma rotary
Thank you for letting me know, I was not sure if I did post it. Way to much to do and another issue I have since the end of last year is I will have to move soon as my house and workshop are going to be demolished to make way for new buildings so I can not expand the workshop for now and it got very cramped there so a lot of projects got frozen.
Not a nice feeling at all, but the good thing is I will have a much larger workshop, but the wait is killing me !!! :)

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