Calibrating the SO3 XXL

CNC Machines Shapeoko
1

I seem to be having issues with the size of parts and features. I went ahead and made a test file of the circle/diamond/square and found it to be quite a bit off. I then sent the S101/102 commands with the correction factors. The square looks good, measures good, but as you can see, the shapes are not good at all. Top is before, bottom is after. What gives?!

IMG_2933.JPG2448×3264 2.33 MB

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Initial checks:

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Pulleys and overall squareness seem to check out. Belts checked and then retensioned as much as possible. Re ran previous file with noticeable improvement but still not as good as it should be. Anything else to check?

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feeds and speeds http://www.shapeoko.com/wiki/index.php/Materials

and direction: http://www.shapeoko.com/wiki/index.php/Climb_vs._Conventional_Milling

there’s also backlash, but I suspect belt tension yet (but be careful to not bend the motor shafts)

5

Same issues. Tightening and squaring everything helped just a little. Straight lines are fine. Circles are rarely completely circular. The problem area always seems to at the initial plunge spot and leading away from it. Inside cut radius’ seem to be the worst. Outside contours are not very bad at all.

6

Slotting is difficult.

Try a CAM w/ a ramping in option?

Rather than cutting slots, try milling them as pockets?

Adjust feed / speed options per

http://www.precisebits.com/tutorials/calibrating_feeds_n_speeds.htm

(linked to from http://www.shapeoko.com/wiki/index.php/Materials#Testing_Cuts.2FMaterials )

Experiment w/ path direction?

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I’ve tried slowing everything down to the lower limits for the calculated chip load and it made no difference. I’m going to play with path directions next.

For what I’m making the slight imperfection has no impact on functionality. You just want your stuff to look pretty, right?

I think I’ll demo MeshCAM and see if it does better. If it does I guess I pony up the bucks.