Robonz wrote:Thanks Gary
You got it! The error is only .03mm or so but that is about 5% of a 0.6mm line width, if I calculate it right. My CNC is good for .01 if I hold my breath during the cut. Am I being too fussy? Before I commit the energy to make something I like to measure twice as they say. If this is the expected error then I will need to work the calculations out in Excel which I don't know how to do right now and am avoiding it haha. Its so much easier to click your button.
Cheers
Keith
Well, I am using double precision for everything so it is hard to see how it could be less precise than, say, excel.
I am not, at present, in a position to reproduce your "test" in order to confirm an error, however, if you are using a CNC your should actually NOT be using the crosshairs to locate the aperture, but the points on the "bead" layer. I am sorry that is so confusing but I think you will understand knowing that I wrote this programme to create my bead disks (shown elsewhere on this forum). The crosshairs were added later to allow people to create disks manually by printing the disk out on paper.
To test this I have created a file using DXFNipkow with a circle through every aperture, and a circle at every aperture with a diameter twice that of the actual diameter, this means that the outer limits of the aperture should just touch the big circles either side - as far as I can tell this is spot on (given the cad software I have).
The points on the "bead" layer are, of course, the centre point of the aperture/bead hole. Now the crosshairs *should* bisect those points exactly, but it may be worth your while to do your "test" with the points rather than the crosshairs (if you haven't already twigged to that), and certainly, when converting to gcode (if that is what your CNC supports) those points would be the correct objects to use.
I attach the test file and would appreciate it if you could confirm my results.
Perfecting an NBTV system is like trying to slam a revolving door...