# Tracing curve with probe.

15 Jan 2014 22:53 #42830 by eslavko
Hello...

I have stock with pre-cutted iregular oval hole.
Is there some subroutine to track that with probe?
I wan't G code to make part to fit on that hole.

Slavko.

17 Jan 2014 00:02 #42877 by eslavko
Replied by eslavko on topic Tracing curve with probe.
Hello...

Seems that noone already have that.
Does someone know the algorithm how to do it?

I know that G38 will be introduced. I think I can make bunch of points that represent the hole. But that curve will be offseted from real edge by probe radius. So how to make line to be at exact edge?
The only idea for now I have is to make measurment for two points close together. This represent line at probe center. Now I should move that line perpendicticular away from probe for radius of probe. Or this is wrong approach?

17 Jan 2014 00:18 #42879 by dgarrett
Replied by dgarrett on topic Tracing curve with probe.
the distribution includes an example subroutine that may be instructive:

/usr/share/linuxcnc/ncfiles/probe-hole.ngc

A modified version usable with ngcgui is at:
www.panix.com/~dgarrett/ngcgui/probefiles/probe_hole.ngc

17 Jan 2014 00:29 #42880 by eslavko
Replied by eslavko on topic Tracing curve with probe.

the distribution includes an example subroutine that may be instructive:

/usr/share/linuxcnc/ncfiles/probe-hole.ngc

A modified version usable with ngcgui is at:
www.panix.com/~dgarrett/ngcgui/probefiles/probe_hole.ngc

I know that. But I need to reconstruct path, not to find center.
Finding center (and path) for circle, square, triangle, and similar shape is easy. But I have to deal with iregular shape, and finding center here means none. Actualy I think I need to somehow find the angle of hole where probe hit. Based on that I should know in wich dirrection I need to go to trace edge.