@Mikell wrote:
Hello everyone! I’m finding that when I’m cutting small pockets, they cut a fraction too small, even with a spring pass to remove any leftover material. The pockets I’ve cut so far are circular and range from 6MM to 30MM in diameter and all are approximately 0.2-0.5MM too small (I find the same thing with squares too!). They’re intended for screw holes, so this makes things difficult. I could manually increase the diameter to accommodate for this, but I’d prefer to figure it out properly.
Interestingly, when doing contour cuts around my object, the object will measure slightly larger than the desired size; inside cuts measure smaller, outside cuts measure bigger. This made me think it might be the programmed size of the cutting tool, but when measured (the stock 6.35MM flat end mill from Carbide 3D) it measured exactly the size that was programmed.
I’ve tried adjusting steps per MM by calibrating long distance moves with a ruler, which results in very accurate and repeatable results along the stretch of the ruler, but when cutting results in an even greater disparity between what I’m telling the cutter to do, and what the cutter is actually doing. Something of note is that when I measured movements of 1MM in opposite directions with a dial indicator, I was getting about 0.1MM of backlash on both the X and Y axes, with the belt tightened fully. Out of curiosity, I loosened the belt a fraction and did the same test, finding far less backlash (0.03MM).
I am wondering if I’m losing steps due to an over-tightened belt. I’ve attached a video showing the tension on the belt ( with both X and Y axes in the middle and the Z axis about 0.5CM off the bottom) - is this too tight? I know I tightened them slightly more than suggested in the guide - I’ve seen posts on this forum saying that can help.
The circles cut look perfectly round and measure so too - from different angles they measure equal sizes.
Could I be missing anything else?
Video: https://www.youtube.com/watch?v=M08vcvbMnAI
Thanks!
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