I’m interested in creating a guide and video on how to calibrate the X-Carve with the 24V stock spindle, which can easily identify issues such as low potentiometer settings and such. I created a calibration pattern designed to test the X and Y steppers individually (2.000" squares), together in sync (2.000"wx2.000"h triangles), and together with varying settings (2.000" circles). I cut it this morning in 3/4" MDF using a 1/8" roundnose bit (0.1225" when measured).
I altered the following settings to really put a load on everything and encourage problems:
Depth per pass: 0.063 -> 0.075"
Feed rate: 40 -> 50 ipm
Here’s how it turned out, not too bad.
It sounded really rough, but I think it was a fair test of the machine. None of the dimensions are accurate and some are off by up to 0.100", but I don’t see any evidence of skipped steps, and the Z-axis looks to be square since there are no stair steps in the big rectangle (0.600" deep).
I figure a test like this can be useful for testing a lot of things at once. I also plan to incorporate how to adjust the step/mm distance once I receive a 600mm scale I just ordered, using the video that Rusty posted at Steps/mm Calibration. Once I get that adjusted, I want to run this test again and see if I can get this dead-on.
My questions for all you experienced folks are these:
-Are my increased settings for the MDF enough to bring issues to light, or should I increase the depth and feed rate even more?
-Should I use a different bit, maybe a 1/8" double straight flute bit instead? It would leave a flatter bottom, but I suspect the dust would load up a lot more in there and cause problems.
-I have my belts tensioned to where it takes about 6 pounds to lift the belt 1" in the middle with the gantry or X-carriage pushed against the static belt side, and I don’t see any indication of belt slippage. Does anyone know an ideal tension force? Does this sound high or low?
-Are there any other videos, references, or procedures you think I can incorporate into this calibration guide?
If anyone is interested in using this test pattern, it’s located at http://easel.inventables.com/projects/2DaOVRoLwaF8mAbPpbumFQ#.