Dross question for Jim Colt

[B Holmes]

Jim, I was wondering if you could explain why it is harder to get dross free cuts on 14 & 16ga.compared to other gauge material when using the low speed fine cut charts. I can get 16ga. pretty close to dross free, but 14 ga. seems to be very stubborn. I have no problem achieving cuts with minimal dross on any other gauge. Thank you for any insight you can provide on this subject.

[B Holmes]

Anybody have any ideas, or is it just me?

[jimcolt]

Dross is caused by: cutting too slow (the low speed fine cut charts are right on the edge of too slow....are designed for machines than cannot go any faster than 150 ipm). Try increasing speed 10 ipm at a time until the dross is gone.

Dross is also caused by incorrect cut height. The height listed in the operators manual cut charts is correct, if you are running higher you will get dross.

Some sheets of steel have a narrower dross free cutting window than others, based on the levels of silicone and carbon as well as surface condition. Generally when you get difficult steel....finding the right speed (faster) is the issue.

If you cannot cut at higher speeds....you can also spray some mig welding anti spatter spray on the bottom of the sheet before cutting, this will definitely minimize dross.


Jim Colt Hypertherm

[B Holmes]

Thank you, Jim. Sometimes I try to make things too complicated. I think I need to go back and rebuild my 14 gauge cut profile from the ground up. For some reason I have been getting inconsistent results on 14 gauge only. Could be as you said, slightly different material properties. Thanks again.

[B Holmes]

Update: I started over and ran some straight line test cuts to verify the correct voltage setting to achieve .060 cut height. I was pausing the code in the middle of the cut so I could measure torch height. Pausing the code instead of e-stopping the machine turned out to be giving incorrect measurements. Seems the THC was moving the torch down slightly before the torch shut off. E-stopping during the cut stops everything immediately, making accurate measuring possible. Two volts less and all is well. Kinda felt like a jug head, but at least the cuts are good now. Hope this can help someone else not make the same mistake.