Scratch Built 4x4 with Modified Toma Config (Long Post, Pic Heavy)

Been almost two years to the day since I got help from Tommy with the Toma configuration on my first 2x2 plasma build. I've built a handful of tables over that time and have been sharing as much info as possible through Youtube, IG and my website. Most recently I designed and built a 4x4 from scratch that would be my machine to keep in my tiny garage. I went and bought everything I have been drooling over for a few years (within reason) and got to work. Wanted to share the outcome:

- Frame is 3x2, 3x3 and 5x2 box tubing, 1/8" wall. Entire frame is close to 500lbs for rigidity.
- 3030 extrusion for gantry and gantry risers.
- Fineline automation gear reduction drives and HD gear racks
- 20mm Hiwin style guides for X and Y
- Prototype Z axis from arclight dynamics with twin hiwin 15mm rails (ebay score)

- Keling 45v unregulated supply, 570oz motors and digital drives
- 5v Proximity Sensors for Homing. Running 2.8 Master branch for Gantry Squaring
- Twin c10 Breakout Boards
- Floating torch head with selectable Ohmic Sensing
- Hypertherm powermax 1000 with Duramax machine torch upgrade.

- Running 500ipm rapids and 50in/s acceleration. 1/8 stepping

Pics

Making some Leveling Feet Mounts

Final Assembly after Paint

Proximity Sensor Mounting

Some Test Cuts

Config Edits

I loved the toma code but there were a handful of things I thought it needed. I am not a programmer but I sat down and mapped out the initial logic so I could get a view of how it works. From there I spent a bunch of time thumbing through the Mann index to learn as much as possible. I built a simulator with UI buttons to generate the move up/down, float switch and arc ok signals from the screens so I could test inside without having to run the plasma. Then it was just pure time in from of that simulator changing the hal files a little at a time to get what I wanted. I'm still not 100% finished but all the screens above are working. This was all done without breaking the core config functionality, If you don't have ohmic or down want to use the features, just leave the boxes unchecked and its just like the normal config.

THC Disable - Pretty straightforward, check the box and it will block feedback from the THC. I also set this up to be done with Mcodes. M100 shuts the THC feedback off, M101 turns it back on so you can post process a cut rule from sheetcam.

Rapid to Cut Height - After pierce delay has elapsed, feed hold would be removed and the lead in would start. I found this would leave me with a funky edge at times if the THC feedback couldnt get the torch down to cut height in time. I used spindle at speed after pierce delay to hold the motion while I forced the Z axis to whatever height is entered into the box. Once it is at the height a comp functions sends the spindle at speed true signal and off we go for the lead in at the proper cut height.

Ohmic Sensing - I wanted to be able to select Ohmic sensing on the fly. Using Generic Mux I swap between the ohmic pin on the board and the float switch pin. The ohmic pin is only active from the M# to the torch on command so there is no chance of splash back tripping the estop. When checking the box to enable ohmic, I also automatically send the float switch to the Z limit so if ohmic doesn't sense or the torch dives while cutting, it will still estop.

New things I am working on:

Z axis probe speed - I would like a different probe speed vs max Z speed. This is proving to be a bit difficult but it is on my list.

Mesa THCAD - I just purchased a Mesa TCHAD10 and 7I96 board for a new build I am doing. What I would like to do is simply use the THC function to get the voltage readings from the THCAD. From there I would run it through the wcomp function and use the over/under outputs to feed the move up/down signals of the toma config. You could even use the wcomp function to simulate an arcok. I've tested this on my simulator with raw float input values and a spinbox from the UI and it looks to be working.

Thanks for taking the time to read through all this, would appreciate any feedback anyone has.

-Stefan-

Yep that was me, built a little 2x2 painted green as a test. Since that machine I've done two separate 4'x2' builds and this 4'x4'. Currently collecting parts for another 4'x4' build to try out the mesa boards and thcad10, got a mail that they shipped today.

tommylight wrote:

If i am not mistaken, yours was the green one, right?
That was a nicely build machine.
Thank you.