Getting back to LinuxCNC plasma table

[acourtjester]

I have a new table I built using LinuxCNC and have a few basic questions for member who are using linuxCNC. I have the table functional using QTPlasmaC and have made test cuts with it. Since I use my table as multi functional (Plasma, router, drag knife, scribe, ect) QTPlasmaC will not work with the other uses. I have tried to use Axis and different Post Processors in SheetCam and it will not function (errors with the G-code), I can home and move the table around with Axis. Looking around it looks like QTDragon may be the screen set I need to use but my lack of experience with LinuxCNC I wanted to see it others have use a different method.
Thanks in advance attached first cut video

[Rodw]

QTplasmac supports scribing and how to set it up and the gcodes used are covered in it's documents. That may also support a drag knife.
For the other uses, I would stick to axis initially and build a new config for it using pncconf. Then select it from the chooser menu when you are not plasma cutting. Sometimes when I have done this, I don't worry too much about the stepper motor settings and copy my known good joint and axis settings from my old ini file into my new ini file afterwards.

Before you start, I would check that your plasma torch is turned on by a normal 7i76e output and use the dedicated spindle enable output on the board to turn your spindle on. Note that the spindle will not move until it gets a spindle.0.at-speed signal.

Once you have axis working, you could consider using qtdragon as it is nice with a touch screen. However, its a new and evolving config. You will need to run Debian Bookworm and Version 2,9 of Linuxcnc. Installing it is described in the V 2.9 Getting Linuxcnc docs. That document also explains how to connect to Linuxcnc's buildbot repositories that are built whenever the source is changed. http://linuxcnc.org/docs/2.9/html/getti ... m_x86_only

I would be very surprised if sheetcam does not have POST for a Linuxcnc router so ask on their forum. There is a POST for Linuxcnc for Fusion 360 which works and what I use on my mill.

[acourtjester]

Thanks for the reply Rod, suggestion to contact SheetCam may help I had tried different post processors but no all for LinuxCNC. I am running bookworm V2.10.0 and did create a QTDragon file and look it over, very different from the other screen sets. Also looked at different Desktops that LinuxCNC has and looks like Xfce fits my liking.
This is one of the errors I got when loading a G-code file. Did you build a new table yet??

error in Axis.png (33.03 KiB) Viewed 3521 times

[Rodw]

Change your post processor in sheetcam for a router one. That gcode file is specifically for plasmac plasma.

[sonbakler]

Nice Tom looks awesome and I will be following this topic as I too have interest in trying LinuxCNC on my setup.

[acourtjester]

I received a post from the SheetCam site and Les said LinuxCNC is the post processor to use. I created a test G-code and now found out I need to have a tool list saved in the LinuxCNC folder. Could not find a YouTube video showing how, so into the manual I go. LinuxCNC seems to be a great way to go I just have problems with the manuals (that is my problem and I know it) There is help and I have received some (thankfully RodW and others) . There is help from the LinuxCNC forum, but I slithering on the ground and those guys are flying at 20000 ft.
It is like teaching an old dog new tricks, I am getting there. If your interested then do it, it is not hard just different. It reminds me of this plaque that Robert sent in years ago, give me a laugh ever time I think about. As soon as I get the software sorted out I am changing to Clearpath servos, I have all that is needed, just want to go one step at a time.

robert.JPG (65.25 KiB) Viewed 3483 times

[Rodw]

There may be an example tool table file in a demo config,
The docs are here http://linuxcnc.org/docs/html/gcode/too ... tool-table
But its much like a csv file in format so you can create it in a text editor.
You really just need T, P, and D set T & P can be both 1. the rest can be zeros

Now this won't make sense unless you have used a massive machining centre with an auto tool changer...

Normally with a hobby style machine its best to generate separate g code files for each tool (say you want to drill some holes then route the edge.) You need to touch off at x0y0 with a wobbler/edge finder then touch off the tool. Best way to do this Is to roll a known diameter cylinder like a milling cutter under the tool until it just touching. Then touch off Z at that height Eg in my metric world I use a 10mm cutter and the touch off Z @ 10
This is the exact same process I use on my manual milling machine.

[acourtjester]

Thanks Rod, question the tool number, when I generate the list do I need to match the tool numbers in the list to the one SheetCam puts in the G-code. Attached is a G-code with a tool number of T21 1/8" end mill, and install the same number in the tool list. Does Axis then automatically match them or do I need to select that tool from the list similar to the way THC values (material list) are selected in QTPlasmaC

[Rodw]

Looks like you need to match the Tool number from Sheetcam to what is in the tool table so make the T in the table to agree with sheetcam (you can add more than one in the tool table.

[acourtjester]

Thanks for the help with this, I sold my other table that used UCCNC board and now can finish up on the LinuxCNC table. I still have the water table to weld up and a spoil board for router work, should be done in a few days, very hot here now.

[acourtjester]

Interesting observation I use 2 different software package to develop G-codes, SheetCam and EstlCam. The both show a reference to the tool that is selected for the plan in the G-code. Here is a screen shot of the first part of the EstlCam G-code. When I run it in Axis it will run without waning a tool in the list, just click on run and it operates the table fine. I tried to remove the reference of the tool in the SheetCam G-code and it told me to Kiss off
it also must be hidden deeper in the code then just a line in the code text.

test G-code no tool.JPG (71.32 KiB) Viewed 3449 times

[cutnweld]

Just a side note, but with linux cnc ohmic you can run your z at 500 ipm down close to your material then probe at 80 or more maybe, wonder how fast Rod does it??? It will save time when cutting large orders

[Rodw]

Yes it runs becasue it does not attempt to load a tool with M6 T21 as the earlier one did. In that case T21 must exist in the tool table.
ref:
https://linuxcnc.org/docs/html/gcode/m- ... l#mcode:m6


The lines you have highlighted in blue are simply comments so they have no affect if they are there or not.

[Rodw]

Just a side note, but with linux cnc ohmic you can run your z at 500 ipm down close to your material then probe at 80 or more maybe, wonder how fast Rod does it??? It will save time when cutting large orders

Yes, I thought Tom had enough on his plate for now so I did not say anything

Here is how fast I probe


This is using a very low probe height and the probe speed depends in the float switch to soak up overtravel as the torch comes to a stop. QTplasmac then probes away from the material slowly until contact breaks. There is a bit of a fine line between the probe speed and the time it takes to go up with the amount of overtravel. YOu need to experiemnt

[acourtjester]

How do you reduce the height of the torch when I retracts from the touch off, mine raises up almost to the upper limit and then start back down??
I need to do some refining of the standard operations.

[Rodw]

I can't quite remember. I think its based on safe height and probe height settings. If you check the QTplasmac online manual it explains it well.

[acourtjester]

Thanks Rod I had not changed any setting yet but will look at this today.

[acourtjester]

Well I finished with the upgrade to the Clearpath servos, those things can make some scary speeds, no stall. I have been playing with the numbers for the velocity and acceleration, and think I am close to the actual travel matching the F value in the G-code. I have the steps per moving to the correct distance.

[caretech]

Nice. Which servo models did you install?

[acourtjester]

I use 2 CPM-SDSK-2321S-RLN one for the Z and the other for the Y(my Y is the cross the table axis, other call it X). And one CPM-SDSK-3441P-RLN for my X axis I used a 72 volt 12 amp power supply for them. Lots of power and no noise.

[TJS]

Have you thought about going to the CandCNC site and downloading the most recent post. Just a thought. Also all the tools in command CNC/Sheetcam were there.

[Rodw]

Have you thought about going to the CandCNC site and downloading the most recent post. Just a thought. Also all the tools in command CNC/Sheetcam were there.

There is no need to. (It would not work anyway) Sheetcam has a Post for Plasmac included these days. Just open it up in an editor as there are some settings at the top to change some features.

[acourtjester]

Thanks guys getting some details worked out. For those who want to know the cost for switching to servos is about $1500, I made my own cables and used a toroidal power supply.

[acourtjester]

Recent changes to table number 10, as a hobbyist I have the time and interest in making changes. This is one of the reasons I built 10 CNC tables, making what could be called upgrades. I have used different controller software and made changes in the electronics and mechanical components.
The newest one were not needed as the table functioned very well and did all I needed with the optional attachments I use. These being Plasma Cutting, Wood Routing, Drag Knife, Diode Laser, and Diamond Scribe. These allowed me to do many different projects and gain experiences to pass on to others.
I have just finished switching from stepper motor (drivers and power supplies) to Clearpath Servos.
This required changes in the signal and power cabling and power supply. I selected similar OZ-IN motors and physical size (nema 23 & 34 type). The power supply I used as a Toroidal unregulated with 72 volts at 12 amps output, this powered all 3 motor. With the Clearpath you supply power directly to the motors and drive and direction signal, which is different from the stepper setup. This was an expense of about $1450. I bought the bare connectors and configured the cables required.
While I as at it I also changed out the mechanical home/limit switches with proximity sensors. I used NO PNP type sensors as they work better with the Mesa/LinuxCNC combination I used.
The attached Video shows the table moving at 320 IPM and the sensor tripping with a 10-32 machine screw. Which I used for the limit/home positions for the 3 axis. My theory is if you move 320 inches at an F value of 320 in one minute it is moving correctly.

[kicktillmonday]

Pretty awesome Tom, I like your setup and the servos must be a huge bonus!