rounded corners

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jeff tunks
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Joined: Fri Mar 31, 2017 10:11 am

rounded corners

Post by jeff tunks » Thu Apr 20, 2017 10:16 pm

Thanks for telling me my problem. my controller is MP 3500 - DTHC IV. What is turned on and can you give me any ideas how to make any changes so i cut square corners instead of rounded corners?

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Post by WyoGreen » Fri Apr 21, 2017 12:42 am

A couple of things you can try. You can use cut rules to slow down on the corners to about 60% of your cut speed. Where possible, you can try loop sharp corners, upper right corner of the jet cutting operations dialog.


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Les Newell
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Post by Les Newell » Fri Apr 21, 2017 10:13 am

In Mach3 you can turn off CV by going to Config->general config and setting the MotionMode to 'Exact stop'. The disadvantage of doing this is that the machine will come to a complete halt on each corner. Try leaving CV on and playing with the 'CV control' values. I never really worked out what they do so you will have to experiment a bit.

If you can increase the motor acceleration that will help a lot.

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Post by PK » Fri Apr 21, 2017 10:38 am

I don't use Mach, but use CV with my controller which probably produces the same results. I believe in a perfect world, the table would not need CV and have high acceleration settings.

But high acceleration settings with a table that can't handle it, will produce jerky results shown on the cut piece. CV attempts to compromise this. Without CV or settings in CV set too "tight" will show up in corners burnt too long as the table mechanics slow down in the corner trying to stay on line and slower acceleration causes this to show up more.

My CV settings (I assume yours, too) will have two parts. Speed and accuracy. The higher the accuracy, the slower the movement through a tight corner. If you can give up a little accuracy in an attempt to keep the torch moving closer to the programmed feed rate, you may be able to get improved cuts.

If you set the accuracy too low to keep the torch moving, a tight corner can look more like a curve. This is all outside of the Sheetcam or any gcode programmed paths.

At least this is what I have found. YMMV


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