Need Help!- Smaller cut line?

[rwhubbard]

I'm trying to make a signature tag and one problem I'm having is the width of the cut.

Currently it's about .055. The smaller I try to make the signature tag the more this is a cut width is a factor. The file has two pierces with some cutting back over already cut lines (THC off).

I've been starting to try lower amps and slower speeds with some success.

I'm using a Hypertherm 1250 with fine cut consumables. The picture is 12ga. mild steel the piece is 6 3/8" long cut at 40 amps, set point 91 feed rate 55%.

Next I need to do some 18ga. stainless. If I could get down to .030 of less that would be great.

Has any one here experimented with this or have any suggestions?

Thanks,
Roger

[WSS]

couple of questions, is that one pierce for each name? Does the torch double cut each line and arc or is it an open profile were the cut ends in a different spot than it starts? Second question, what is the finish on the part? I like that finish. That is a good looking cut as well, it looks just like a signature.

.030 kerf might be hard to get. Our machine using finecut @ 40 amps on 12ga gets .049 once in awhile and that is only when the THC is running close and fast with lower than recommended volts.

WSS

[rwhubbard]

Thanks, the finish is a done using a Dynabrade orbital sander with 320 grit, it's fast and easy if there aren't any deep scratches. Most of the things I make end up with a high polish and the orbital gives me a more consistent surface than I can get with a angle grinder.

There is some cutting back over already cut lines the H for example starts on the top right and double cuts the left vertical and the horizontal part. The d double cuts the loop.

In larger pieces the finished pieces are much better but in the smaller sizes the width of the cut is too wide.

I was working with a waterjet cutting place but they weren't to excited about working with intricate files in small quantities.

My plan is to try some low amp settings and lower set points with a slow cut speed.

[WSS]

Have you tried 25amps yet? I have not tried under 40amps so far. Do you have the we-cim/cuttingshop package? The reason I ask is today I cut some parts that I scannned and traced in cuttingshop and noticed a few things. The detail that seemed to change the shape of the cut was how long in between points the cut was. the curve varied so I needed to add points to grade out the curve and use the deform tool to match the raster. After cutting and looking at the edge, I could see each section between points by the jaggedness and jags-per-inch(is that a word?). I am wondering if it is important how the arc or line is optomized or converted and how to get rid of that.mI do think that would narrow the kerf by at least 10 to 15 percent if it could be smoothed out. Anyone have any ideas on that?

WSS

[rwhubbard]

Don't use WiCim but had a similar problem with curves when converted in Corel Draw to DXF. If I added more points that helped. I now use an aftermarket program to do the conversion with much better results.

At times I get a weird anomaly that caused jagged jerky cuts, if I slow down the torch that seems to help smooth it out. When I looked at the DXF file at high magnification I find a back and forth loop in what should be a smooth curve. The path back tracks over its self sometime more than once where the original is fine.

I did try 25 amps with some success, trying different speeds and set points getting the cut width down to .035 in straight cuts. I realized I need to do a more real world pattern to see how it works on curves. If I come up with any conclusions I'll let you know.