What are your PM85 settings for cutting 18ga?

[motoguy]

I've got some 18ga mild steel I need to cut tomorrow. I haven't cut this thin in the past. I'm looking for any tips/tricks you may have for cutting it with the finecuts, aside from "book rates". Specifically, I'm looking to maintain cut quality, and willing to sacrifice dross cleanup. I see that 325ipm, 78v and 45a is the book spec.

I'm curious if any of you are having success at a lower amperage and speed. I know I've read of guys cutting down to 25a with the finecuts, on thinner stuff.

Thanks!

[jimcolt]

The book spec will work best. You can reduce the amperage to 40 and cut at about 225 ipm with a little more heat input which may cause dross and some slight warpage. Lower speed means more heat is absorbed by the material.....the cause of dross, warpage and a wider kerf. There also are low speed finecut charts that suggest speeds under 150 IPM.

The problem with reducing amperage much below 40 with the Finecut consumables.....is that you lose energy density in the arc.....it cause an arc with a lower "Amps per square inch" range.....again cuasing lower cut speeds and more heat input.

I have always been 100% satisfied with the 18 gauge cuts at about 225 to 250 ipm. Be sure that the cut height remains at .06" at all times.....adjust your arc voltage to ensure physical height is maintained and be sure to use the 948 shield. Jim Colt Hypertherm

[motoguy]

Jim,

I know I shouldn't be surprised. I cut the 18ga today at book settings on my Bulltear table. It cut wonderfully. It was probably the most dross-free cut I've made, with the exception of the corner slowdowns.

[jimcolt]

Work with Matt at Bulltear to see if you can increase acceleration / de-acceleration ....this will improve the dross in the corners that is caused by sluggish acceleration. If you increase acc too much you will get unstable, wavy cuts exiting corners. Jim Colt Hypertherm