Homemade probe cal problem

[Perry Fisher]

Version 3.207 Beta

This is my first attempt to calibrate a homemade probe. The probe is made from a broken ball stylus. The remaining shank is Ø1.5mm x 39mm long ground flat on the end. Below is the probe build from my PROBE.DAT file. When I calibrate the probe I'm getting a Ø.098mm diameter instead of Ø1.5mm. What have I screwed up?

Thanks



ITEM:TIP1.5BY39_SHANK_NOBALL M2
begintip
ribcount 10
color 142 142 142
cylinder 0 0 0 0 0 -3 3
cone 0 0 -3 3 0 0 -7 1.5
color 100 100 100
cylinder 0 0 -7 0 0 -39 1.5
color 255 0 0
hotspot 0 0 -39 0 0 1.5 1.5 1.5 disk
endtip

[Matthew D. Hoedeman]

Well, are you doing a calibration or a shank calibration?

[Perry Fisher]

Well, are you doing a calibration or a shank calibration?

Shank calibration.

[Matthew D. Hoedeman]

Well, I would treat it as a 'ball' probe, with the ball at 38.25mm, that would make the 'end' of the probe the 'bottom' of the ball. When you do a shank calibration, does it not also calibrate the 'ball' on the end of the probe? I don't do shank calibrations so I am not sure. If it does, then the end of your shank must be treated as the bottom of the ball and you MUST calibrate it using only 2 levels and it must calibrate on the equator of the sphere or it will not be hitting right, and then use a big enough 'depth' so that the shank calibration does not hit anyplace where a ball would be IF that probe had a ball on the end.

[Perry Fisher]

I do a standard cal, user defined 2 levels at 0° & 90°, and turn on shank cal at 3mm deep.

[Matthew D. Hoedeman]

Have you tried doing a manual calibration of that tip so that YOU can make sure it is touching in the right places? It would be real hard, but it could be done. If it gives you something close to the diameter of the shank for the tip calibration, it might be able to give you good data with a DCC calibration.

[Perry Fisher]

I have not tried a manual cal. I will do that.

[Paul Sarrach]

Well, I would treat it as a 'ball' probe, with the ball at 38.25mm, that would make the 'end' of the probe the 'bottom' of the ball. When you do a shank calibration, does it not also calibrate the 'ball' on the end of the probe? I don't do shank calibrations so I am not sure. If it does, then the end of your shank must be treated as the bottom of the ball and you MUST calibrate it using only 2 levels and it must calibrate on the equator of the sphere or it will not be hitting right, and then use a big enough 'depth' so that the shank calibration does not hit anyplace where a ball would be IF that probe had a ball on the end.

Yes Matt, it does Calibrate the end and see it as a ball.