Langmuir Crossfire Pro 1.6mm/16 Gauge Sheet, not detecting Z-Height and dragging tip across cut surface

CrossFire ® PRO
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The tip seems to be flexing the material out of the way, and then the spring in the steel is for some reason then making the Z Height to 0mm

Then, once it cuts, it will either cut fine, and simply drag the tip across the surface, or it’ll grip the surface and drag the sheet.

When it drags the sheet it destroys my XY Zero and ruins the sheet.

Given these are full sheet fully nested files, I have to start from scratch on a new sheet, already ruined 2 of the 6 sheets I have here.

This is frustrating, because I had actually planned to use all 6 sheets, so now I have to go order more sheets because if this issue. Wasn’t doing this last time I was cutting 1.6mm, however this time it seems to be an issue for god knows what reason.

I can’t find any settings to adjust the sensitivity of the Z-Axis sensor.

Doesn’t do the same with 3mm steel.

Also, if it manages to get a cut and not drag it’s alignment out, it’ll self fix once the THC kicks in and detects voltage about 50% of the time, sometimes the THC doesn’t and actually drives the torch back down, basically forcing it to sit on the surface and keeping the cutting height at 0mm.

You would think the THC would try and keep the height at the set height all the time.

Video is at:

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definitely too much spring in material. looks like the front left corner must not be touching slates when i do springy material i try to set a piece of heavy steel on the edges out of the way of course to hold material down.

the slow Mo video looked cool even though it was trashing you cuts.

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So why isn’t the THC fixing the height though?

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It is pushing the material down and thinks the material is lower than what it is. then it doesn’t have time to correct the height before it is moving the material. i can’t say your certain just the nature of the beast. I haven even tack welded the corners to slates to make then lay down.

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So would reducing my time fix this?

Though I’ve noticed even once it starts cutting, as it gets to a lower area, the THC is actually forcing it back to the plate.

So it starts at a high point, sets a 0mm height, then as it moves away, it maintains that 0mm

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Are you running smart voltage? what does it read when cutting?

Is the metal warping and hitting the torch or is the thc lowering the torch?

Have you changed the tolerances of the voltage.

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No Changes to tolerance

Even before it warps

So imagine it’s going in a straight line

It starts a a clearance of 0

It goes 50mm and the metal dips away by 2mm

So now the metal is 2mm away from the head

I want to cut at 1.5mm

Rather than lowering by .5mm, it lowers now by 2mm to maintain a clearance of 0mm

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that would be because you are using smart voltage, is that right? the way that works is it a very very short time after torch fires it assume it is at cut height. Then it takes a voltage sample the is the voltage it will raise and lower to. so, if it fires touching material take the sample voltage it will do its thing to keep that voltage at whatever height it is. you would be better to try writing in a voltage may e.

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Right, so when it takes it’s reference voltage it says that’s “correct”

I thought that was why you calibrated the voltage under the “Test” menu?

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my understanding is that is to confirm that it is reading voltage not to calibrate anything i could be wrong. You are running the rw45 right? i don’t remember what voltage to write in. i would guess about 130ish. i upgraded to a Hypertherm 65 most material i cut i use around 130 for it just a guess though

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Yeah, might be the go.

At the moment I’m sticking my fingers in there to hold it down. So that’ll get me done for now.

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Sounds good you can also weight down the loose corners with some weight. Let us know if you figure it out.

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Yeah, I cut what I could manually, will be rethinking how to do it.

My old man actually suggested I make some weighted blocks and thread them so that I can hold down the sheets and screw them to the table.

So I’ll be investigating that method.

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The problem is that you can’t use smart voltage if the sheet is flexing that much. With smart voltage turned on, it takes a voltage reading during the first .25" of the cut and uses that voltage to maintain that height during the rest of the cut. With that much flex in the plate, its taking a reference voltage while the torch is in contact with the plate and it will try to maintain that voltage by keeping the torch in contact with the plate.

As you have already figured out, you need to hold the sheet down or use a nominal voltage setting. You can run some test cuts by holding the sheet down and get a nominal voltage reading. Then you can enter that voltage, so the THC will use that to maintain the torch height on warped metal.

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