Not reading plasma arc voltage accurately.

[Stanmyers00]

Good morning. I am running the Bladerunner Ethercut 5 with the SuperZ II. This is the second time this has happened, first was a couple of weeks ago. After a few sheets it went back to reading normally. Running .125 inch aluminum sheet, first steet ran fine. Second sheet kept diving into the material. I notice the voltage readings were way off, 160ish with DTHC off. I normally run this with a voltage of 142, but to keep it from diving I had to run it at 162 V. I have checked, replaced, and cleaned all wire connections and clamps. Completely shut down and unplugged the entire system, this usually helps when it looses its mind, but not today. I did the PMW test and the voltage read 109. Any thoughts? Thanks.

[weldguy]

The voltage it's reading could very well be accurate, is your air clean and dry? You can determine this pretty easily by looking inside the nozzle and on the shaft of the electrode. If you see greyish/black stains swirling around the electrode shaft or inside the nozzle I would try cleaning up your air supply and you will likely get better DTHC reliability.

[TJS]

Is it diving on corners. What is your DTHC response time on. I have mine on slow usually, faster than that I get issues.

[Stanmyers00]

Weldguy,

Our maintenance crew keeps the air dryers in great shape, but I will inspect just to make sure nothing has happened. Nozzle and electrode looks fine.

TJS,

no, it is cutting corners fine, but as soon as it comes out of the first corner and DTHC shuts off, it plummets. When I set the voltage higher, it will cut the entire plate of parts, 42 pieces, no problem.

[TJS]

I see Tom responded to you on the CandCNC site. Hope you get it working as it should. Post your issue and the results when you find it. I was having trouble with my torch oscillating up and down on thicker material (3/8" and up) and sometimes crash. I already had my DTHC responsiveness to "slow" which did not seem to really fix my issue. I then posted more about thicker material issues. I made a new config profile and called it thick material. I slowed the acceleration and speed down for all axis. I am still playing with it though. Good luck.
T.J.

[Stanmyers00]

Thanks everyone. Sorry for not getting back sooner. It turned out to be a bad ground connection. As long as DTHC was on it would run fine, but as soon as it kicked off and started using the voltage to set cut height, it would dive into the material.

[TJS]

Thanks for posting your results. When you state "bad ground problem". Where was it. Was it the worklead ?
T.J.