Poor Cuts at End of Program

I have been trying to iron out the imperfections on a file I downloaded from Fileshare.

I have gotten to the point almost everything is cutting good, except the last few points.

I can’t seem to get a good cut on a hole (7.5mm dia) at the top and the terminal point on the outline cut. That is the stopping point for the program.

This is 18 gauge, 30 amps, 3200mm/sec at 55psi. I have 2.5mm lead-in/lead-out. Fusion 360. Primeweld Cut60.

The hole for a mounting screw never completely cuts out, and the terminal point for the outer circle always cuts inboard a bit too much.

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Cant tell, is that pierce for the hole all the wat through?

First up the air to 60 psi flow, 55 is to low and you may be running low at the end.

Second holes are cut at about half the speed as the rest of the cuts. And again if the hole is the last thing you cut you air pressure may be to low.

What size compressor do you have? You need 100 to 120 psi coming to the plasma cutter and be able to maintain 90 psi at about 5 scfh

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Yes, it pierces and cut all but a small tail. I’ve cut 5 of these and it does the same thing every time.

Thanks for the advice. I still very new at this and due to my background (auto design), I am better at the CAD than the cutting.

I have a 60 gallon Cambell-Hausfield compressor. It has no problem keeping up with the demand. Only kicks on once on this job. Not always same point in the job, and no other poor cuts even right before it kicks on.

As far as the 55 psi, I am getting almost no dross and all the rest of my cuts are fully through, so I felt that was enough pressure at the cutting point. I’ll bump it up a bit.

My compressor is set to kick-on at 100psi and off at 120, so I should be okay on delivery pressure.

Again, the rest of the cut is going very well. The last two steps are cutting that 7.5mm hole, then all the way around the circumference. That last little turn towards the inner side of the circumference cut right before the torch shuts off is also a problem. It has been 2mm on several of the runs.

Can you post your G-Code and f3d files?

Here is the file used to cut the part. I honestly don’t know what an “f3d” file is.
Welcome To Our Porch Rev3.nc (78.5 KB)

Fusion 360 file. Go to file menu in upper left corner and click Export. You can save the f3d file to your computer.

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Here is the file. Thanks for the replies.
welcome to our porch 30 round Rev 3 v8.f3d (438.0 KB)

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The toolpath on the outside cut is setup as an interior cut. Inside cuts travel counterclockwise, outside cuts clockwise. So the outside cut is on the wrong side of the cut line as is your lead-in and lead-out. The lead-in/out is causing that divot on the outer edge near the hole.

You need to edit the toolpath profile on the geometry tab. Click the red arrow for the outside cut. The arrow will change direction and move to the outside of the line. This will result in a much cleaner cut as well.

As far as the hole goes, the tool path appears correct. However, with holes around a 1/4" or smaller they do not turn out too well cutting with plasma.

Another thing you might consider, is extruding your sketch into a body while in the design environment in Fusion. It make creating the tool path much easier. Instead of having to select each cut individually, you just select the body and Fusion selects the cuts and their direction for you automatically.

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Thanks alot for the quick help. I will make the updates and give it a try.

The few things I’ve made so far, I did extrude. Guess I just forgot on this one. Since there were only 4 cuts to select, didn’t really cause me any issues.

And the “inside/outside” cut choice I still need to get my head around so I don’t screw that up in the future.

Man, I have a lot to learn! :grinning:

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everyday…everyday…you never stop learning with plasma cutting

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I switched to outside on the outer circle tool path. It definitely helped. On two fo the three I cut last night, the mounting hole (7.5mm dia) even cut out completely, even though I made no change to that path.

On the air pressure, I was mistaken in my original post. I had it on 60psi. Compressor never even had to kick on during a full cut cycle at 3200mm/min. It was kicking on during the postflow cut each time.


Thanks again

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