My (kinda) budget build 4x4 plasma table

[robertspark]

do you have a torch height controller at the moment?

before buying one, it is worth while considering costs you still need to spend.

mach4 is $200, plus a thc.

linuxcnc + plasmac is free
a Mesa 7i96 is $119
a Mesa THCAD is $69

yes you would have lost the sunk cost of the ether-mach at $229..and you would not need the Bob, but maybe a simple relay board .. but you could try to recover some of that cost on resale via eBay etc.

(note, I don't presently run linuxcnc, but it does appear to be the most cost effective route at present and one everyone should at least be aware of and the costs)

I am also not sure what the demo restrictions are of mach4. mach3 would not allow you to run a thc and I think had a number of gcode lines limitation. it is worthwhile checking the mach4 documents what the demo mode is limited to

I know of people's reluctance to use Linux....trust me, I've installed it enough times... my problem is, I design in cad that only runs on Windows (must check if fusion 360 will run on Linux as I've recently changed to using that now from inventor.... but I still use autocad for simple tasks) and installing anything on Linux always seems like a long job... then when you want to change something it can be a right royal pain, YMMV and it gets better the more you use it.

[robertspark]

.

Yes, you would set up an output on the motion controller then set that up as "SpindleOn" in Mach4 as shown below.
Note: disclaimer.... I am not an expert with Mach4 (too many menus, tabs, dropboxes etc etc.....)

This is another one that has been frustrating me quite a bit and I can't wait the get it working. I spent quite a bit of time looking for information on how to turn the torch on/off and most the info was either misleading or so confusing that I just couldn't figure it out. I read somewhere that you also need to set spindle RPM at max.

I'm currently using Mach4 hobby demo also. I didn't want to purchase a license until I knew that I could get it working first.

sorry, my bad advice!

I took a look at the ether-mach documentation page and found one on plasma / thc setup.

apparently there is an ether-mach plasma screenset that is installed and in the outputs there is a torch output

http://ether-mach.com/static/manuals/Et ... de-1-0.pdf

the confusion of mach4... with a 1000 names for similar things.... I guess it's flexible...

[Rodw]

do you have a torch height controller at the moment?

before buying one, it is worth while considering costs you still need to spend.

mach4 is $200, plus a thc.

linuxcnc + plasmac is free
a Mesa 7i96 is $119
a Mesa THCAD is $69

yes you would have lost the sunk cost of the ether-mach at $229..and you would not need the Bob, but maybe a simple relay board .. but you could try to recover some of that cost on resale via eBay etc.

(note, I don't presently run linuxcnc, but it does appear to be the most cost effective route at present and one everyone should at least be aware of and the costs)

I am also not sure what the demo restrictions are of mach4. mach3 would not allow you to run a thc and I think had a number of gcode lines limitation. it is worthwhile checking the mach4 documents what the demo mode is limited to

I know of people's reluctance to use Linux....trust me, I've installed it enough times... my problem is, I design in cad that only runs on Windows (must check if fusion 360 will run on Linux as I've recently changed to using that now from inventor.... but I still use autocad for simple tasks) and installing anything on Linux always seems like a long job... then when you want to change something it can be a right royal pain, YMMV and it gets better the more you use it.

For CAD for home use, I would go to the cloud and use Onshape and leave everything shared with everybody and its free. This a serious competitor to inventor/solidworks and you can run it on any device, even your phone. Then you are OS agnostic.

One of the problems with Linuxcnc is that it requires a real time kernel (now PREEMPT_RT rules here). When I went to LinuxCNC, I had to patch and compile the kernel which takes about 5 hours to do. PREEMPT_RT is used extensively in the music industry and some major automotive players (like BMW) have adopted it and have put corporate resources in to development of it. Finally, there are packaged deb installs of the PREEMPT_RT kernel. Yesterday, I took delivery of an Odroid H2+ single board computer. I had a USB with Linux Mint 19.3 (tricia) ISO on it. So I installed it and ran the scripts on this page
https://forum.linuxcnc.org/9-installing ... on?start=0
and in a few minutes I had the PREEMPT_RT kernel and Linuxcnc installed.

Mint is so smooth, I have trashed Windows from my PC at home!

The Odroid has perfect latency to handle an Ethernet Mesa card and also a UART which should allow connection to a Hypertherm RS485 interface. The only headache I had is that the new Realtek 2.5gb LAN ports on the Odroid do not have drivers available (and not well supported on Windows either) so I had to download the driver to a USB stick and then click and install it from Linux Mint. A quick reboot and I had network ... plus I have a spare network port for a Mesa card like the 7i96.

Back to CNC though. Linuxcnc is a late starter with plasma machine support. However, Mach and other Windows based systems will never get close to it. The reason for that is that with Linuxcnc, it is the motion controller. With Mach the motion controller is the Smoothstepper or equivalent card. Looking at the Mach document Robert shared, it is a simple up/down bit bang interface.

With Linuxcnc it just needs the torch voltage (from the THCAD) and it has the full (enormous?) resources of a PC and its real time motion controller (not a small embedded controller). So Linuxcnc can apply much more sophisticated torch height control using its sophisticated PID controls. Plus becsue it has full access to the motion controller, it can do smart things like torch voltage sampling and velocity anti dive and a host of other things that physically are impossible with the Mach architecture.

And its only going to get better because idiots like me are adding additional features to the motion controller specifically for plasma control. eg. I have finally cracked one thing I have wanted to do for a long time. That is calculate the arc radius and if its a hole or not in real time. When I'm done, this will allow the motion controller to manage hole cutting without adding any special G code.

[robertspark]

.... PREEMPT_RT kernel. Yesterday, I took delivery of an Odroid H2+ single board computer. I had a USB with Linux Mint 19.3 (tricia) ISO on it. So I installed it and ran the scripts on this page
https://forum.linuxcnc.org/9-installing ... on?start=0
and in a few minutes I had the PREEMPT_RT kernel and Linuxcnc installed.

thanks for the tip, that I was not aware of

I have an odroid xu4 languishing in a box as I found it too slow for bootup of a 12x3" dashboard I had created, which I used an asus tinkerboard for your instead. (both with emmc)

I will have a look at repurposing it as dual booting my CNC has been a pain (I keep w10 and Linux on separate ssds .... everyone is happy then if I do something dumb... which I do regularly

is there an easy screen sharing app for linuxcnc .... I use shh, but it's the remote graphical desktop side I am looking for. I use something called octopi for my 3d printer (a raspberry pi interface to marlin (3d printer firmware) with a graphical front end accessible through the lan or web + use something called discord to get updates of the 3d print status and screenshots of progress at 10,20 etc % progress..... whilst it's not good practice to leave 3d printers or CNC machines unattended, with a wife and kids I may only get a few minutes to set something up and press go and then I can remote monitor or stop it if needed.

SOLIDWORKS too expensive, but again thanks for sharing the tip on onshape (I used it a bit when it came out with the free carrot it started out with years ago).

[Rodw]

If you type sudo apt-get install xrdp, you will be able to remote in from the Windows RDP client (MSTSC). I've got a couple of Raspberry PI4's here tucked away powered with PoE and they are quite pleasant to use that way. I'm sure there is a Linux client fro XRDP.

[robertspark]

my error...
Odroid H2+ = intel processor

Odroid XU4 = arm processor.... I didn't think linuxcnc liked anything but i386/amd64 OS's, so I'll need to shelved (as I did not think that RT kernels played nice with arm + linuxcnc

[Rodw]

my error...
Odroid H2+ = intel processor

Odroid XU4 = arm processor.... I didn't think linuxcnc liked anything but i386/amd64 OS's, so I'll need to shelved (as I did not think that RT kernels played nice with arm + linuxcnc

Yes H2+ is a real PC
There are some ARM configs for Linuxcnc now. I don't know how you would go but the PI4 is supported. Its a bit slower so you need to run a 0.5 kHz servo thread instead of 1 kHz. The PI4 now has a real NIC on board. The earlier versions had a NIC via USB so it was not usable for real time to control a Mesa ethernet card.

[Dmaxpwr]

sorry, my bad advice!

I took a look at the ether-mach documentation page and found one on plasma / thc setup.

apparently there is an ether-mach plasma screenset that is installed and in the outputs there is a torch output

http://ether-mach.com/static/manuals/Et ... de-1-0.pdf

the confusion of mach4... with a 1000 names for similar things.... I guess it's flexible...

I've tried using the s3torch set but it comes up with errors for missing information, and I haven’t been able to locate a plug-in, or whatever I need to fix it.I gone as far as uninstalling Mach4 and reloading it, but still no luck. I just tried to load it again and took photos of the error messages. Here are the screenshots.

[Dmaxpwr]

do you have a torch height controller at the moment?

before buying one, it is worth while considering costs you still need to spend.

mach4 is $200, plus a thc.

linuxcnc + plasmac is free
a Mesa 7i96 is $119
a Mesa THCAD is $69

I already have a Price THC and had it wired in but when I wasn't able to get the table working I figured that I would remove it and just deal with one thing at a time. I'm defiantly a little hesitant with switching over to another system, especially one that may be a little quirky to load. I'm struggling enough with Mach4 and I still don't have this running, so I think that I'll stick with this for now. At least until I can get the system up and running. Hopefully at that point I might have a little better understanding of how all this stuff works.

[robertspark]

what version of mach4 are you running?

the whole long version number please

[Dmaxpwr]

For CAD for home use, I would go to the cloud and use Onshape and leave everything shared with everybody and its free. This a serious competitor to inventor/solidworks and you can run it on any device, even your phone. Then you are OS agnostic.

Thanks for mentioning Onshape, I've been using a free trial edition of Fusion 360 and was wondering what I was going to do when it runs out of emails to use for the free trials .

[Rodw]

I could be wrong but I'm pretty sure the Mach THC won't run unless you buy a licensed version...

[Dmaxpwr]

I started replacing the wiring for signal from the C25 BOB to the stepper drivers tonight with some 23/4 shielded cable. I also ordered some 16/4 double shielded automation cable for the stepper motors. It's due in tomorrow so I should be able to get all the motors rewired this weekend. I'm remote mounting the cabinet and will end up with almost 30' runs, so just in case I end up having to upgrade the stepper drivers, I decided to use 16ga cables. I'll make sure to separate the 23/4 cables and the 16/4 cables much as possible. I'm also replacing the C25 BOB with a new one, I figured that this would be a good time to do it. I'm crossing my fingers that it solves the flickering homing switch input LEDs.

After that I'll install the 20T pinion gears on the Y/A axis and see if I can get the motors tuned. Then back into the PLC to see if I can figure out where to apply the offsets and get the torch on trigger working.

With any luck I'll be able to get this thing fired up this weekend.

[robertspark]

I could be wrong but I'm pretty sure the Mach THC won't run unless you buy a licensed version...

https://www.machsupport.com/forum/index ... #msg199556

it will work with all functions for a limited time period... until your total time is up

that was a limitation of mach3 not mach4

[Dmaxpwr]

I could be wrong but I'm pretty sure the Mach THC won't run unless you buy a licensed version...

https://www.machsupport.com/forum/index ... #msg199556

it will work with all functions for a limited time period... until your total time is up

that was a limitation of mach3 not mach4

I can run the demo for an almost unlimited amount of time as long as I don't load a gcode, good thing because I'm just barely past the point of having to research every step and everything I work on takes me a ton of time. The aprox.6 minute timer starts as soon as I load a gcode, once it runs out it gives you a pop up message that you timed out. If I load a gcode and then remove it prior to timing out, then I can just keep running the program.

[Dmaxpwr]

what version of mach4 are you running?

the whole long version number please

Sorry, I didn't notice this question, lots to read through. I'll get the number tomorrow morning and post it.

[Dmaxpwr]

what version of mach4 are you running?

the whole long version number please

Mach4 Demo
Version 4.2.0.4300 Unlicensed
Build 4300

[robertspark]

what version of mach4 are you running?

the whole long version number please

Mach4 Demo
Version 4.2.0.4300 Unlicensed
Build 4300

I'll have to have a look, the reason why I ask is because mach4 (when I was attempting to use it with an ESS ...) it was notorious that some ESS plugins worked with some mach4 versions and then all of the sudden a mach4 update was issued.... and functions in the plugin broke.... then you needed to wait for the plugin to be updated in the hope that the broken function would be fixed

[Dmaxpwr]

It is definitely quirky. When I opened it up this morning I found that Mach4 didn't see a motion control devise, it was looking for a "wxMach.set" which didn't exist in my folders. So if I tried to skip the process the program would just close. I has to go into the system folder and rename one of the screensets to "wxMach.set" just to be able to open the program. When i did get it to open, all my info was lost, I had to re-map everything.

Oh well, part of the learning curve I guess.

[robertspark]

turn the hardware on first before the pc so the firmware in the motion controller initialises the ethernet device on the motion controller

[Dmaxpwr]

turn the hardware on first before the pc so the firmware in the motion controller initialises the ethernet device on the motion controller

I usually do, but didn’t even give it a thought this morning. I turned Mach4 on to get the version number and never initially turn on the hardware. I guess that’s a mistake I don’t have to make twice.

[Dmaxpwr]

It finally felt like I had a productive day, I finished replacing the 24/4 signal wiring to the stepper drivers and installed the 16/4 cable from the drivers to the motors. I made sure to keep these separate from each other. Since I still needed to change the gantry cat track, I figured I might as well do that while I had everything apart. I also swapped out the pinion gears to the 20T ones.

I tuned the motors by clearly NOT doing the math right, I came up with 500 SPU (20T, and 10 micro steps). When I ran the Mach4 step wizard I found that I was WAY OF, it only moved about 3/16" when attempting to move 1". Luckily the wizard makes it easy for dummies to get the proper steps. Over all it went very good, although it took a fair amount of time to dial it in. I was able to get to within 1/64" over a 46" span on the X & Y/A axis. The HUGE improvement is consistency, speed, accuracy and both Y&A axis are now set identical. I went from a max (with occasional missed steps) of 150" per min. to 1000" per minute. I set the motor velocity @ 700" & acceleration @ 75, everything seems to move pretty smooth with this setting so I figured it was a good starting point. Isn't it funny how much a little electrical interference can cause so many problems.

I was able to figure out how to set the offsets (learning curve) and everything seems to home out properly now. I attempted to run a test gcode that was supplied with Mach4 but still run into a macro error and it stops (no torch connected yet). I attempted to start on the next line and the Z axis tries to plunge all the way to the floor. So I skipped that line too and the machine will follow the pattern pretty good by the looks of things. I ran the same pattern with a sharpie zip tied to the torch. The frame is straight but the slat holder and aluminum sheet I was using is not so sharpie moved quite a bit, but it defiantly looks like its following the pattern.

I'll probably re-nstall the THC and try and figure out how the get the torch to fire tomorrow and hopefully be bale to do my first cut. Wish me luck

[robertspark]

acceleration is more important than rapid (G0) velocity / speed.

you have a 45xp,

https://www.google.com/url?sa=t&source= ... fXUFBZFeKl

I would suggest aim for the rapid feedrate equal to the highest in the book (325ipm).... any more than this is not required except to stroke your ego (I use to run mine at 600ipm.... because I could, idiot! the highest number in the 45 (nonxp) book was 400ipm!

I would then change the acceleration to 0.3g (116ips/s) as this is a recommended target which is used by commercial tables ..... it is a target and has some basis as a target.

at 325ipm and 0.3g the minimum arc RADIUS that you could cut at a constant linear feedrate of 325ipm is about 0.25inches. say you need to cut an L shape, and ignoring any G64 parameters you may have set regarding tolerance (is they are very big) there would be a 1/4" radius formed between the two linear paths.

the recommendation for cutting small circles (bolt holes and radii etc) is that you allow the feedrate to drop to 60% of the book linear feedrate for the arc....

viewtopic.php?f=4&t=22037&p=131942&hili ... er#p131942

so 60% or 325ipm becomes 195ipm. some dross will form, but this allows the machine to both run a tighter inside radius now at 0.3g ( 0.091 in radius) and it also allows for the cut edge to be more square given the trailing arc of the plasma torch will be able to run
closer to the start of the cut.

MACH4 doors not appear to be able to use tolerance settings in g64 but it has a CV Wizard.... no idea how. that works!

In sheetcam I tell sheetcam my material thickness as it sets g64 tolerances accordingly and automatically

the smallest hole you can. get with an air plasma is a diamerter of about 2x to 3x the material thickness (this is not true with very small thicknesses as the kerf and pierce time needed to be considered too).... EG 26ga ms is 1/160" thickness

[robertspark]

1/5" pitch, 20T = 4" per revolution

200 motor steps X 10 microsteps = 2000 steps per revolution

2000 steps per revolution / 4" = 500 steps per inch

[Dmaxpwr]

1/5" pitch, 20T = 4" per revolution

200 motor steps X 10 microsteps = 2000 steps per revolution

2000 steps per revolution / 4" = 500 steps per inch

Well that weird, thats the exact same number I came up with, but when I run the wizard it calculates it to 3044.9415778564