1. ## A few ?'s about touch probes

I am in need of a 3d image on a black piece of plastic. It has alot of different pockets and contours and was thinking about getting a touch probe to reverse engineer it. I will be using Mach 3 software with the probe. The main question is the part as some 90 degree corners in it, when the probe reaches this does it tell the mill that the Z axis needs to raise then continue plotting the part? I would also take it that to do a full 3d drawing on the part I would have to use my 4th axis to rotate the piece x-degrees so that the probe would be able to take its next path, correct? What is the typical amount a part would be rotated to take the next measurement and what is the typical travel speed to use with a probe? Sorry for all the questions but I dont know all that much about them. Thanks in advance.

2. I've got a Roland probe scanner and have never used a pobe in conjunction with Mach, so this might be of limited help but.....

The result of a probe scan is, as far as all I've seen, a surface generated from all those points plotted by the probe, it's not g code. You then have to import that surface into some sort of CAD/CAM software to manipulate and/or generate g code. If your probe hits a 90 degree wall, the resulting scan will show a 90 degree wall.

As far as scanning a full 360, there's 2 ways to go about it and I don't know what Mach supports. You can scan a part on your 4th axis like you would mill it, in one "pass", or scan in multi passes with a rotation in between. The problem with multiple passes is stitching the scans together, doable, but sometime frustrating. As far as how many passes? It's sort of like milling, you'd need to determine it by the job, do you need to try to get undercuts, how long is the reach of the probe, that sort of thing.

3. Thats exactly what I was wondering about. Now if the probe detects a 90 degree corner that is say .500 high, will it tell the machine to raise the z-axis, and stop the X or Y travel so it can continue, or do you manually have to do it? I figure the diameter of the tip of the probe will play part in its accuracy of a 3D part and also the amount of time it take to make the scan (smaller probe=more pass'). Thanks for your help

4. Now if the probe detects a 90 degree corner that is say .500 high, will it tell the machine to raise the z-axis, and stop the X or Y travel so it can continue
If you are talking about during the scan, yes, you are correct, the scanner will move up in Z until there is no resistence in lateral movement, then it will continue. The scanners I have seen move down to touch, then up a hair, then over a set distance, then down again. They don't run like a mill in a continuous path, they just accumulate points at lowest Z. The software fills in the gaps between points to make a surface.

You're right in that the lowest resolution of the scan is determined by the tip size, but mainly by the parameters you set. Just like in milling, you need to tell it the stepover between paths and how far between each point. If your paths and points are close together, you can capture fine detail, but just a warning, high res point scans take a long, long time.

5. Thanks I think one might would work for me. Maybe I would run the probe in the morning and let it do its thing while I work. Got more wheels turning in my head now.