[Hasenburg]

Hi everyone,

I've built my own CNC Router (based on the Avid CNC) Hybrid (Mill & Plasma). The Milling works flawlessly, but I am really struggling to get reliable plasma cuts.

My software/hardware setup is as followed:
- Mach4
- TMC3in1 THC
- Hypertherm 45 XP

My main issue is, that on a regular basis (on every second cut - if I try to do bigger cuts, it occurs on every cut) during the cut the "ARC OK" signal is being disabled, which leads to a stop of the cut. The cut does not stop immediately. First the torch goes off, then the machine moves for 3-5mm and then stops.
I can cut rectangles (50x25mm) with mostly (7/10 times) no "ARC not OK" Error, and the cutting height (1,5mm) and speed seems to be ok, too. But if I am trying to cut bigger pieces, the errors appears every time.
I can't figure out, where to tackle this issue...

Does anyone have an idea for an approach to solve this issue?

[rodw]

From the docs I read, it seems that the THC is designed for raw (undivided) arc voltage. Last time I looked, the 45XP did not have raw arc voltage output.
So that looks like an incompatibility. How do you read the arc voltage? Its possible the voltage is too low and it tries to correct this by raising the torch to increase the voltage and this extinguishes the arc.

[freecnc]

Having a similar issue except with a PrimeWeld 60.
The ARC OK signal flickers even when only a millimeter or two away from the surface.
Essentially will probe fine and move into position, but after a brief arc initiation and pierce, no motion and a "waiting for Arc OK" error.
Showstopper...