Lead In and Pierce Duration

I finally managed to get my plasma table operational for the first time this evening and sucessufully made some great initial test parts out of 1/4” mild steel plate. I’m using a Hypertherm 45XP with a machine torch and programmed the tool paths with SheetCam. Hypertherm has a feed rate sheet that was useful for the first try and I dialed it in from there.

At any rate, you can tell where my cut starts on each part (see pic) but otherwise the cuts look great. I have the pierce delay set at 0.6 sec (as recommended by HT) and designed by parts to start with an arc lead in that is 0.1” long before it actually gets to cutting the part. I also have a .05” over cut at the end of the cut (which could very possibly be causing the bad edge).

I have a bit of work to still do in order to get this thing dialed and plan to mess with it more tomorrow. Can anyone recommend some things I can try regarding my setup to eliminate the rough start/finish to my cuts?

Thanks for any feedback!

I don’t know if you can do this in Sheetcam but take a look at the lead in angle for the starts. Also maybe bump up the length. I’d expect the kerf to be more in qtr inch than thinner steel. Try a lead in/start about 2x your kerf. The two settings allow the arc to establish outside the finished adge and slide in as it comes up to speed without having to make an abrupt angle change.

I’d do the same for the lead out/end.

Very nice cut otherwise and pretty ballsy to jump right into qtr inch :smiley:

Yes, SheetCam does have different adjustable options for lead in/out, length, etc.

I started thinking about the shape (an arc vs. straight line) for the lead in. It’s possible that an arc like I’m using might actually be slightly slower than going in at a 45 - which could be overheating the cut in that one area. There are a few options for lead in/out so I’ll have to play with it.

That’s also good info on the lead in length vs kerf. I’ll give that a try as well.

Thanks for the ideas!