Cutting Bad Curves - urgent help needed!!!

[sion2413]

It cuts perfectly straight lines but jumps when cuts curves and swirls giving a jagged finish.
What can be the issue?

I have redrawn the artwork over 3 times and still get the problem

[chasxjs]

I would suspect something is mechanically loose. Perhaps a stepper motor mounting or drive gear. Try powering the motors so they lock and then attempt to move the different axis's by hand while checking for any play.

[gamble]

Anything making noise when you move the Y or X axis?
Any debris on the screws or track or whatever setup you have?
Broken bearing?

[WyoGreen]

Depending on how I look at the picture, I come up with a couple of different ideas. If I assume the X & Y axis are aligned with the grain of the metal, that is from lower left corner towards the upper right corner, it would appear the two right divots are in line with each other, which would indicate a mechanical problem. But then I look at the upper two divots, and I can see they are where you transition from a straight line into a curved line, which to me indicates a drawing problem. So I'm at a bit of a loss as to the cause. Perhaps if you post the whole drawing and cut file we can come up with better ideas.

Good luck, Steve

[PlasmaMac]

It cuts perfectly straight lines but jumps when cuts curves and swirls giving a jagged finish.
What can be the issue?

I have redrawn the artwork over 3 times and still get the problem

I think this post might be in the wrong section, since it looks like it is not for a plasmacam machine.

All plasmacam have servos, which provide really excellent corner acceleration that can provide really smooth cuts on corners and round holes.

Anyways, if this was happening on a plasmacam machine you can control pretty much any aspect of the cutting motion, including corner acceleration (even specify lower cut speeds on smaller hole diameters) and also control rapid travel when crossing kerf to jet the overall job done faster. These perimeters can be easily adjusted for any custom job that requires precision on intricate cuts. You'll find this on your plasmacam software under Settings >Machine Control >Cutting Motion. Like so:

Cutting motion.JPG

JAG

[Shane Warnick]

Might try cutting a circle on one end of the table and see if it shows up. Then on the other end or another area. If it's still there and in the same spots, then it's the gear rack on the carriage and gantry top. If it's not there on both, then it's in the gear racks that are inside the rails.

One other thing to check, is to initialize and home the gantry. Pull it back against the microswitch, and look at the other corner. Is it touching too, or is it off just a bit? If it's off, then the gantry isn't in the gear racks straight. Could have been this way when you put it together, or you could have a weak spring, or the wrong spring, or maybe a hard collision. Anyways, it's easy enough to fix, just turn it off, pull the spring, and home the gantry with a small (SMALL) amount of force, and it should jump over a tooth or two and line the gears and the racks up. Reinstall the spring, and see if the prob is gone.

If it's off just a tooth or two, it will run but won't cut perfect shapes, and can sometimes bind and cause it to jump slightly, causing what you are seeing there.

Shane

[Joe Jones]

Please post the actual cut file you were using when you got these results.

I am betting that the file is bad.

If not, then there is a bit of slag on your gantry that the bearing is rolling over at a certain point, causing the carriage to jump over it and then fall back into line.

These are just guesses though. Post the file so we can really look for a problem in the cut path.