I’m baffled by a recently noticed problem with carving curves with our shapeoko3 running CC and CM. I get a slight jump up the Y axis when I get about 330degrees through a circle. Doesn’t matter where on the bed I operate or the radius, so probably not steppers? I designed the circle in CC and also tried importing a dxf and svg of a circle done in Corel Draw. Same result. I get no logs/gcode errors. This also happens in arcs. Italicized letters get sloppy. I’m running current versions of both CC and CM. Is CC generating bad code? CM mishandling it? Something else altogether?
There is one software problem which previews okay, but causes problem when cutting which I’m aware of — too long lines, but that had been solved in pretty much all of the communication / control programs I’d thought.
Please check the wiring — that it altered orientation points to a wiring fault to me.
Is it only circles and arcs? or do the corners of squares look a little funky too? I was having the same problem a month or so ago but it wasnt just my circles it was squares also,mainly the corners…I tightend my belts and i tightened the heck out of my lower v wheels on the z carriage,there was some play in the z plate and now there isnt…problem gone ever since.
I had problems with circles being circular. First I tightened the belts and it helped a little bit. Next I adjusted the v wheels and bingo. Because all the gantries are potentially moving during a circular motion, adjust ALL of the wheels. If there is any free play in the v-wheels were they engage the v on the gantry, you’re not going to get good circles. My drills also got much better after this adjustment.
So far, the belts and V-wheels haven’t done the trick. I did a square and it came out perfectly. I tilted it 45 degrees, and I got the same issue I get with circles. So, for some reason, the X and Y movements don’t seem to be synched at diametrically opposite points of the cut and in the same place on the cut no matter where on the cut bed I run it.
I created the cuts and gcode in Carbide Create. Here is the gcode for the circle:
The software shouldn’t be at fault — please check the pulley set screws (and then re-check the belts and V-wheels — it’s a bit tricky to get the tension right for the belts at first and takes a bit of practice).
Also, pens are subject to getting bent and pulled off-course and may not give a good indication of the actual performance of the machine — try similar paths cutting with a V-bit or similar.
More than 3 years later, this solved my problem too. The belts were tight enough (I thought), but still had this problem. Decided to just tighten as much as I could. Cleaned up all my slop and fixed the little divots I was getting near the corners of squares.
