Coordinate inaccuracy
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I built a corexy camera handling device. However, I am having problems with movement accuracy. When I move the car to the right and back, the return point does not coincide with the starting point. But when I move the car to the left again and return, the return point coincides with the starting point. This does not depend on the number of micro-steps (16, 32 ...) I am sending the images.
Does anyone know what the problem is?
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I don't know your machine at all, but typically this is caused by a phenomenon called "backlash".
Imagine that there was some gap in the belt-to-carriage that allowed the carriage to be a little loose. When you move one way and back, it doesn't "quite" get back to the original position.
Things people try to control it:
- Tighten belts
- Add a rubber band or two from the carriage to the printer structure to "preload" the carriage towards X=0 and Y=0 (or the other end, it doesn't matter)
- Tip the printer on an angle to use gravity to "preload" the carriage.
Take some images while you gently press on the carriage left and right and see how much "slop" there is in your mechanical system. If it's really tight we'll have to look at other things.
If I understand COREXY right, diagonal moves only run one motor right?
Try a diagonal and maybe the other diagonal and see if you get similar accuracy.
