Problems cutting holes

Hello everyone,

I am hoping to find some help or guidance on how I can fix or improve the cut quality I’m getting on some holes I am trying to cut. I have the Crossfire PRO with the Razorweld 45 CNC available from Langmuir. We run the cutter with shop air at around 115psi.

I do not have any previous experience with plasma cutters so most of the settings I use for my cuts come from research I have done here and online.

While running some tests to try and figure out what settings would be best for cutting some holes I ran into a problem where the holes kept coming out as ovals. The material I am using is 1/8" hot rolled mild steel. My cut settings are as follows:

35 amps
0.079" cut height
70ipm cut speed for contour
25ipm cut speed for holes
arc lead-in = 0.125"
no lead out
kerf width = 0.055"

We are using all the standard consumables that came with the cutter originally (will look for the list and update)

Parts are made in Solidworks 2023 and tool paths are made in SheetCAM.

Any help is greatly appreciated.

With a RW45, for 11ga (.125"), I’m at 45A, 100 ipm, 0.9 pierce delay, cut height .06", pierce height .15".

At 35A, I would expect your ipm to be 70-80. Pierce delay would increase as well. Cut speed for holes tends to be better at ~60% of your cut speed.

Reduce your cut height as SheetCAM will add an additional .02" to your entered cut height.

Arc lead-in can be reduced to .07" and should provide no issues.

Edit - Had my 35A ipm backwards!


Yes agree with Terrance. That looks like the cut height is making a mess.

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Make the changes suggested above and see if the holes are still oval. If so, your couplers between the stepper motor and lead screw are slipping.

Are these your first cuts? have you had good cuts?
Might be couplers slipping


Thank you so much. These settings have given me some of the best edge quality I have seen come off our table. The holes are still coming out as ovals so I will look into the couplers to see if they need tightening.

I was wondering how do you come up with or where do you find your cut settings? I have had a hard time locating a reliable resource, and while the forum is an awesome way to learn it would be great to have something I can reference immediately.

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These are not the first cuts of this table. I have had some alright cuts before but nothing as clean as what I got after the above changes. Checked all three couplers which are all tight and I did not notice any slippage during movement, but the hole are still ovals.

For the Razorweld 45, at 45A, I used Hypertherm’s XP45 cut charts as a basis, reducing the speed by 33%. This provided a good starting point to adjust cut quality. Pierce time varies, as the FireControl controller requires ~.5 sec to send the command. (So for 18ga, I’m at .5s. For .25", I’m closer to 1.6s.)

For less than 45A settings, figure the percentage change from 45A and adjust cut speeds accordingly. (I’ve only just started playing with 30A consumables with the RW45.)

As for your cuts, the best I was able to achieve with the RW45 @ 45A was +.002" X / +.004 Y on a .105" hole. I believe my lead-in was around .015 - .025" arc (thru Fusion.) SheetCAM provides good resolution for this as well.

I suspect speed and cut height were your problems!

Good luck & good cutting!

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Just out of curiosity, what thickness material? What size (diam) holes?

Edit - My bad, you’re cutting 11ga (.125")

Hole diameters are 0.25" and 0.281".

We are trying to see if we can cut clearance holes for 1/4 bolts to cut down on machining and fixturing time on the drill press.

Very doable. I do that all the time. 0.280 / .281" for a 1/4" bolt is good. (+.030") Try to verify in SheetCAM that your lead in starts close to the center of your hole. If the settings seem to place it off center, adjust as needed.

For 11ga, I don’t think I’d run lower than 45A, but that’s my preference.

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Select “start at center of circles” and define the largest circle that you want to start at the center of. I have mine set at .75".

This setting will start at the center and spiral around to start your circle.