Pierce height on small holes

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White Bear
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Pierce height on small holes

Post by White Bear » Wed Apr 07, 2021 4:51 pm

I'm using MyPlasm and a PM85. When cutting small holes my torch pierces at .15" then begins to cut without dropping to .060". This does not happen on larger pieces. The strange thing it operates properly in demo mode when the torch doesn't fire. It also shows the proper XYZ coordinates while running the program with the controller off.
This is causing excessive taper. I'm about at my wits end with this machine. Every time I fire it up a new bug rears it's ugly head.
Anyone else run into this issue?

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acourtjester
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Re: Pierce height on small holes

Post by acourtjester » Wed Apr 07, 2021 7:18 pm

When cutting small holes you should run at about 60% speed for the thickness of metal you are cutting. This is setup in the planning of the G-code, separate out the holes into one layer and set the speed to the lower value. Most of the cutting will pierce at 0.160" and cut are 0.060". Thin metal can be pierced at lower setting like 0.090". Check the Hypertherm manual for the pierce and cut heights for metal thickness.
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adbuch
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Re: Pierce height on small holes

Post by adbuch » Wed Apr 07, 2021 11:06 pm

This sounds like a configuration problem with your MyPlasm controller and/or your sheetcam settings (if that is what you are using). What size are your small holes, and what thickness material are you cutting?
David

White Bear
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Re: Pierce height on small holes

Post by White Bear » Thu Apr 08, 2021 10:22 am

Thanks for the replies. Yes I'm using Sheetcam for G-code. MyPlasm will configure a secondary speed for small holes so no need for a second layer. MyPlasm overrides Sheetcam for cut speeds, pierce height, etc. I think that I have it set at 1.25" or less and my secondary speed is about 60%. All of that is working as programed. I have e-mailed Proma but they are in Poland and it usually takes a few days or longer to get things sorted out. I'm currently cutting 0.688 holes in 3/8" material. The program is all working until the torch fires then it won't drop to cutting height on small holes. I cut some 3/4" thick parts with no holes yesterday and it worked flawlessly.

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acourtjester
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Re: Pierce height on small holes

Post by acourtjester » Thu Apr 08, 2021 2:35 pm

If you din't use layer how do you separate cutting holes with an inside offset and cutting other parts with an outside offset.
DIY 4X4 Plasma/Router Table
Hypertherm PM65 Machine Torch
Drag Knife and Scribe
Miller Mig welder
13" metal lathe
Small Mill
Everlast PowerTig 255 EXT

White Bear
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Joined: Tue Jan 28, 2020 11:58 am

Re: Pierce height on small holes

Post by White Bear » Thu Apr 08, 2021 2:49 pm

Sheetcam does it automatically. I can't think of one instance that it's been wrong. I've had a piece or two where I had to reverse the cut direction on the entire project but that was probably my fault in the original drawing. I always use outside offset and it's good. Clockwise on the outside cuts and counter on the inside cuts.

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