Weird speeding up and slowing around curves

[The-Meerkat]

I finally got my retrofit/upgrade to UCCNC equipment and software up and running earlier this week. I’m starting the process of dialing in the settings, speed, etc. I’m trying to figure out why I’m getting big fluctuations in speed as the torch goes around easy curves. I’m sure I’ve got something setup wrong. I attached a link below to a video that clearly shows the issue several times.

[adbuch]

There is probably a setting for reducing speed and/or acceleration around curves/corners. I use Plasmacam Design Edge for controlling my table and under the Machine Control, Cutting Motion section it has settings for both "Corner acceleration (G)" and "Slower on circles/curves under (diameter, inch)". You probably have some similar settings that you can adjust for your particular situation.
David

[The-Meerkat]

Same with UCCNC. I guess I’ll be re-reading the manual more closely.

[adbuch]

Same with UCCNC. I guess I’ll be re-reading the manual more closely.

[acourtjester]

Looking at the video are you using any cut rules in the G-code. And in the drawing could the oval have line segments at the point where the torch pauses.

[The-Meerkat]

No cut rules. In Sheetcam I am seeing a lot of vertices which must equate to lots of line segments. What can I do about that?

[acourtjester]

If you post the SVG file I will look at it to see what can be done and will reply with steps to correct, if I can
Is the problem only in the outer oval or in other places while cutting??

[robertspark]

uccnc, check the corner error max setting in the manual and associated settings. look at the diagram. read it again until you understand it, then use some practical numbers for corner tolerance that align with your plasma cutting kerf.

don't set it at 0.001" corner error max as you ain't going to get a thou of tolerance on a plasma cutter

0.1 or 0.05 may be a better number that works for you.

linear motion gcode joining linear motion gcode (G1 > G1) is one thing.... arcs joining arcs is another thing.... there is a discussion on it here.... basically fiddle with the settings you have available and try to understand them. it works as well as it can.
http://forum.cncdrive.com/viewtopic.php ... ax+circles

[The-Meerkat]

While I was dry-running some different settings today, I accidentally crashed the torch into the material and broke my floating head mount. Rats! I’ll be taking that off this weekend and putting my old mount back on.

ACOURTJESTER, No SVG file. It’s just a freebie DXF file that I got ahold of awhile back. It seems to happen on all arcs though. Since I didn’t have the problem with my old Gecko Drive/Mach3 setup, I’ll bet it’s incorrect settings in the new UCCNC software. So far, I’ve found a few of them.

ROBERTSPARK, I’m going to read through everything you pointed me to carefully. I already found the Corner Error Max value is currently set at 0.001 as you predicted. That must be the software default setting NASA uses. I’ll be changing it this weekend too. I’m mostly making artwork, not aircraft parts. Also, Linear Error Max is also currently set at 0.001. Arc Radius Tolerance is at 0.10. What do you think, keep those settings or ?

Thank you both.

[adbuch]

Here is the svg file.
David

Ford Oval.svg

(170.62 KiB) Downloaded 81 times

Ford Oval.svg

(170.62 KiB) Downloaded 81 times

[The-Meerkat]

Awesome. Thanks David.

[The-Meerkat]

Problem solved. I slacked off on Corner Error Max and Arc Radius Tolerance settings per RobertSpark’s suggestion. There is a huge difference in cutting speed around arcs now. Much faster.

Thanks.