You need to install the machine shield for cnc cutting. The drag shield is used for hand cutting only. When you install the machine shield set the cut height to .060, your cuts will improve and dam near dross free cuts.
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Ok. I haven’t been using the drag shield. But the deflector “shield” I was using basically just has the tip completely exposed. Like shown on the diagram that was posted above.
I am not sure if this would be causing the issue, but take a look at the letters in the bottom pic. It’s like the lead in/out in some letters didn’t do anything.
Here is a cut from this morning.
160 ipm
40 amp tip w/ machine shield
110 psi
Cut height 0.05
Pierce height 0.12
Pierce delay 0.5 sec
Lead in/out radius 0.01, angle 60 deg, distance 0.06
Feed optimization toggled on at 80 ipm
Better, but still looks really rough.
I did notice a thin black layer of “soot” on the front side of the retaining cup under the shield when I was changing the shield. I wiped it out and blew out the holes. Not sure if this is normal or not.
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Looks better. However, it almost looks as if your path never returns to the pierce (Especially on the R.)
Can you share the .F3D file from Fusion? That can allow me / others to look behind the scenes.
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Let me know if this works. I’m trying to do it from my phone at work. I can export the file when I get home tonight if not. Thanks. It should show up as an ornament.
I agree. It also looks like this cut is going the wrong direction (unless the pierce is not being fully successful):
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MAGA ornament.f3d (419.7 KB)
Let me know if the file works. I agree that it seem almost like the angles were opposite direction for the lead in/out, but I watched it in the simulation and it appeared correct. I appreciate everyone’s input and hope I can get it resolved soon.
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I made a couple of changes. In design, I extruded your sketch. No issues there. In Manufacture, I redefined the setup and placed the origin at bottom left corner. In your tool path, I removed the chain selections, and selected the face. Changed Smoothing to .001. (My preference.) For you lead-in / out, I had to reduce in order to get the profile to cut.
Take a look at the attached…
MAGA ornament v2 SW.f3d (337.8 KB)
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@Simworx thank you for taking the time to adjust the file. I just got home and replaced the swirl ring, electrode, tip, and shield with brand new parts. I generated the g code and did not change any other settings. Here is how it looks without busting off any of the dross. Some areas look better but it still seems kinda funky on some of the lead outs.
Have you confirmed your cut height by stopping the cut and measuring? Although, that does explain why the middle “A” and “G” cut pretty well.
Notice the “M” repeated a similar error but the four "A"s have differing problem issues.
In this run, I would say that if your amperage was a bit higher with the same speed, you might have had better success.
The “R” cut out pretty good, compared to your previous picture.
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I did measure it and it looks like the pierce and cut height are both what they are programmed at. Should the lead out height be the same as the cut height? It looks like it stays at the cut height until it comes all the way up to love to the next point.
As for the problem areas you can see they match up pretty well with the lead ins/outs.
Definitely. The cut height should not change until it goes to its next “rapid” movement for the next contour.
That explains the "M"s and the "A"s.
Try to CAM with a finishing overlap. In your case I would say 0.02 inches. That is in the fourth tab, fourth row down. That will force the torch to follow that area again, ever so briefly.
Edit: Looking back at your first post stating you have a “Pierce Clearance of 0.055 inches”. I would cut that to 0.0. It would be better to have more room for the actual lead-in/lead-out.
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I did not see what thickness your cuttin?
And what is the speed?
@ChelanJim Thank you. The overlap conceptually makes complete sense as the why it is causing the issues at the lead in/out points. I just tried adding a Finishing Overlap, but keep getting a linking constraint error for almost all of the letters and it discards their pass. I have tried reducing the distance down to 0.0001 and it still does the same thing. I tried reducing the distance for the lead ins as well and still no joy. Any suggestions.
@Knick It is 14 gauge steel and I started at 200 ipm and the last one was at 160 ipm, with the feed optimization slowing it down to 120 ipm and 80 ipm respectively.
wow I cut 14 ga at 90ipm at 45 amps
What changed to give you the error? your lead in needs to be very small with that small text.
I was able to get your first F3d to cut.
Post your latest F3d
I just went through that exact same exercise. Don’t do any more than 0.01 finishing overlap. At 0.02 it is a nightmare to get all of the contours to participate.
What I ended up doing was cutting the sweep angle to 90 degrees with a lead-in radius of 0.02, but you could start with lead-in radius of 0.01 just to try to make it a bit easier. At first, I also eliminated the lead-out since we have the finishing overlap.
Each time you run it and it drops a letter, go back and edit to select the preference of lead-in for the dropped letters. If you already have a “preference” selected for that contour/letter and it did not use it - then delete that previous selected point (Hold down CTRL and click on the previous point). Now pick another point and see if it will work. I found that straight sections were more reliable to take.
Eventually, I got all letters to take and added the lead-out back in. But believe me, it is not necessary if you have the finishing overlap.
Edit:
I used your f3d and just worked with the sketch. Here is what I changed in Passes:
This is the Lead-in settings:
You can see on this image where the lead-in sweeps in and the the finishing overlap copies over for a brief bit.
I tried the same thing and got about the same thing. I dont see why adding overlap drops some of the letters.
Makes no sense, something is wrong I just put a .0001 over lap and it would only cut one letter. That letter is no different than the rest. Set over lap to 0 and it cuts all of the letters.
I would ask Autodesk
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Totally agree Knick. That simple sketch about did me in. That is some graduate level stuff right there. I don’t know what is making it so hard.
MAGA ornament Chelan.f3d (292.9 KB)
This is with that finishing overlap.
