Beating a dead horse bevel

Hello all,

I notice my torch was not plumb after getting some bevels in my cuts. After spending the morning getting it pretty dang close I did a test cut and noticed I’m getting a bevel on X and y but on the opposite it looks great. Can’t really explain why.

Attached as much info as I think is necessary.

I’ll add the code from my laptop.

Here is the code. (892 Bytes)

Main-Components-Of-A-Plasma-Torch-Cutting-Tip bevel on the top cut height is too high. Bevel on the bottom its to low.
Wide part of arc should be centered.

Shouldn’t THC be handling this?

You set the cut height is set in fusion. Example : Cut height set to . 06

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It is set to .058 in Fusion. Here is a snippet from the G-code. G0 Z0.058 (Cut Height)

So is the THC commanding it to change height and causing this issue?

I think that anything less than .05 will disable THC. But, I could be wrong. I keep my setting at .06 for almost everything.
Bad tip can also produce bevels. If its worn out the arc exits on an angle. Something to check.

BTW. Thank you for your quick response.

Okay. I will adjust the z and try again.

I did attach a picture of the consumables. Not sure if they are all that bad.(Still learning)

Your tip looks toast. Make sure you have a tip or nozzle that is not smaller than your amp setting. 40 amp nozzle at 50 amps will last about 1 minute.

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Just for some bathroom reading. :relaxed:

Plasma, waterjet and laser cutting systems from Hypertherm.

I just did another cut and it looks like the Z is moving up which is causing the bevel. I set the height to .06 and it moved up on it’s own.

Replacing the tip and trying again.

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Dumb question? Is the work clamp on the metal your cutting?

yes sir it is

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After replacing the tip the bevel is significantly better but still exists, primarily because the torch lifts when cutting.

When you get time watch this video on the operation of the THC /IHC. It’s a very good explanation of its operation and how it determines its height. Demystifying the Langmuir Crossfire CNC Plasma Table Initial Height Sensing (IHS) system - YouTube


All the consumables in the picture are bad and need to be replaced. The tip is toast, the electrode is firing off center and bad, the swirl ring has been hot now that’s bad and you should also change the shield as its warn out also. It will never cut straight with those consumables.


What is your live voltage reading in firecontrol when the torch is lifting?

The THC doesn’t know what your Z height is and it doesn’t care. All the THC does is try to maintain the target voltage by raising or lowering the torch. It gets that target voltage number in one of two ways.

You can type in a “nominal voltage” and the THC will raise or lower the torch to maintain that target voltage, regardless of the cut height that you programmed. Your programmed cut height will only be used when the THC is inactive.

With “smart voltage” turned on, it takes sample readings for the first .25" of cutting and uses that sample as the target voltage. If the IHS system is not actually setting the Z height where you programmed it, the THC will just keep the torch at that incorrect height. The IHS system tends to place the torch much higher than your programmed height, so you should do some testing and adjust your settings to achieve the correct actual torch height. The biggest culprit is the Springback and Backlash compensation recommendations. In my experience this should be set to Zero.