Advice on retrofit of proprietary plasma table?

[antpdrake]

sounds good, also i forgot to mention my plasma cutter is a Thermal Dynamics.

ok, so i might order a Proma compact 150 and wait for v4.14 to come out, sounds like the go hey?

[cnckeith]

the proma 150 is the unit we are using for the plug in development

[citterly]

This is great.
I build a CNC router that used a Marlin based controller, typically used for 3D printers.
I want to convert it to a plasma machine, but managing the torch is beyond its capabilities.
So this is a perfect solution, go Acorn !!!

I have a Miller Spectrum 125c plasma, it's a very light duty machine, but will be fine for what I'm doing and to get started in this area.
The Proma THC role and operation make sense to me in terms of taking control of Z movement in order to maintain cut quality.

The part I'm struggling with is hooking into the actual plasma machine.
Taking over trigger control makes sense in my mind, that should also control the on board compressor.
Voltage for maintaining THC is going to have to come from somewhere within the plasma machine, but where?
Maybe that's in the torch as well?

A wiring diagram is included for reference.
Thanks for any guidance !!

[justafarmboy]

I am just starting into the world of CNC. Purchased a Hypertherm 45xp that someone ordered and never picked up. It came with a machine torch and they threw in handheld just to get it out the door. I've been playing with the idea of a cnc plasma table for years and have figured out different setups only to find out that they become unsupported very quickly. I ran across your acorn controller mentioned in another forum and the idea sounds very promising. I like the thought of the major controls being made by the same company. For the beginner, it takes away a lot of the unknown issues that have been frightening me away for so long. As soon as the THC and plasma controls are added in, I think you will have new customer.

[Mad Machinist]

cnckeith,

Can you give a time frame on the release of the plasma plug in for the Acorn? I am building a plasma tale right now and it is about three months out for completion. I plan on a CNC mill and a CNC lathe here in the near future and would rather have only one control system to learn.

[cnckeith]

I'm pretty sure it'll be ready by then.

[Sportbikeryder]

While it will narrowness focus, the best chance of having a product that will actually work and interface properly with a plasma unit is probably to go with something that communicates directly with the newer Hypertherm machines.

The machines have a direct connection to both work with torch height as well as setup the machine settings themselves from the operator 's PC. Also, as mentioned previously, Jim Colt is a hypertherm rep and also a lover of DIY machines of all kinds who has provided countless tips and support for anything plasma, even if it is not related to Hypertherm. Jim has or at least had a Plasma Cam at his home shop and makes small plasma tables as well, including demo units for showcasing plasma cutters at tradeshows.

Support for other types of plasma machines will likely require (sometimes substabtial) external interface hardware which I likely outside of the scope of Acorn itself, unless Centroid is also hoping to dive into the hardware side as well (which could be a good thing).

John

[Mad Machinist]

I'm pretty sure it'll be ready by then.

Thank you.

[Makerron]

Please look at AGELKOM CAP04 capacitive torch height control.it will run in your option 2 and 3. Kinda pricy but very accurate and trouble free.

[mighty_mike015]

I'm going to go ahead and throw in my 2 cents in. This my imaginative of what it should do.

Assuming option 3 from previous page.
Macro or motions to sense material. Can be a Centroid macro or user written. I would write my own. Requires one or two inputs depending if machine is equipped with floating head, ohmic sensor, or both. Same macro or section of code will have the pierce height, pierce delay, cut height variables, torch on output, and arc okay input used. The cut height position should be set as the new Z offset(Z zero). Centroid can already accomplish this.

Once this sequence is complete then we need to tell the Centroid to start reacting to THC commands or not. So a macro/g-code will have to be made to start reacting to the THC up/down signals. Another G-code to turn the reaction off. There should be parameters to define a max allowable range that the up and down can vary from the defined cut height( z zero). If commanded higher of lower after the limit is reached, the control maintains last height until a command puts it back within the parameter limits. This feature should also accept a delay factor. This gives the arc a defined time to stabilize before the control starts reacting to the up/down signals sent by the THC.

Once cut is complete, the Torch on output will be turned off.

That is the most basic scenario.

Other Centroid specific feature:
Anti-Dive feature: When the feedrate of the machine varies from the desired cut speed, specifically slowing down the THC will command the down signal. This occurs when the decel portion of the motion control or the constan velocity portion cuts the feed down. There should be a parameter that defines a threshold amount to keep the down signal from plunging the torch into the material. Example: Parameter XXX is 90. The defined feed rate is 100 ipm. If the actual feedrate dips below 100 * .90(90%) = 90 ipm, then the the down signals are ignored from the THC. If feed rate override is used then the this feature should be relative to the new desired feedrate and not what the program commanded. The feature will need to be activated and deactivated as users discretion. ON/OFF with m or g code.

There is also an anti-down feature out there that allows the height to increase, but not decrease. This can be enabled and disable by a g-code. If the anti-down is enable then the control ignores all down signals from the THC, but still obeys all up signals until the anti-down is disable then it goes back to reacting to both up and down signals.

In conclusion:
Output for Torch on
Input for Arc Okay
Input for Floating head sensor - most practical height sensing to me
Input for Ohmic sensor - another option
G300 - start reacting to up/down signals from THC
G300P3 - start reacting to up/down signal from THC after 3 seconds. This is not a dwell. The code continues on but the 3 second delay is in the background. The P (or whatever letter designation you want) should accept a variable G300P[#100]
G301 - stop reacting to up/down signals from THC
G302 - Enable anti-dive feature using parameter XXX as the threshold compared to user commanded feedrate.
G303 - Disable anti-dive feature
G304 - Enable anti-down feature
G305 - Disable anti-down

Disclaimer: I am not professional in the subject, just what I have gathered and understood from my research.

Thanks for reading,
Mike