Touch probe for metal working

Hello Linuxcnc community.
People call me Marko, and I come from Croatia.
I have build my own Mechmate and just upgraded to lienar rails.
I have been using touch probe on my Mach3 for metal, but Mach3 is very unprecise, and I heard good things about this product.
I am willing to give it a go, and want to know is there such an addon for a circle touch probe, and Z height probe.
Here is the link of the probe in action (not my link)

Thanks,

Marko

Might want to look here...
www.linuxcnc.org/index.php/english/forum...e-for-center-of-hole

Rick G

Hey Rick,

As I am new to linux, and especially linux for CNC, I am wondering can this be used like the on the video I posted?
I only used metal rod attached to dril chuck and it worked out without any other industrial probes?
Thanks again,

Marko

Hi

The video is ingenious but rather Heath Robinson.
All he is doing is centering to a position, which is only as good as his manual and visual centering of the ring over it , in the first place.

There are much better ways to centre on a mark, including centering microscopes, usb camera mounted in the spindle or even just a plain magnifying glass and a sharp centre in the spindle.

The Linuxcnc probe routines are designed for a proper probe, with the switch in the tip of the probe, not using a conductive make between a bit and a piece of copper ring.
So you can easily find the centre of an existing hole for instance to ream it out, even in non conductive material , using the probe, your method is only 'good' for one thing and reliant upon a circuit.

www.linuxcnc.org/docs/devel/html/gcode/gcode.html#sec:G38-probe

The probe need not be an Renishaw industrial one, you can make one with good repeatability quite easily.

Once you have one, there are many more things to do with it than find the centres of holes.
People digitise entire 3D parts using probes and then replicate them from the probe data.

regards

Hi Arc,

As I intend only use for holes, and I only need it for aluminum cuting.
I dont need fancy stuff, only for positioning.
Basic conductive probe is perfect for me.
Do you have any recommendation probes which I can purchase, if they are acceptable with the price.

Don't get me wrong.
If all you want to do, is what you were doing under mach, then you can do the same.
You would just have to set the probe routine to stop on make instead of break contact.

You just have to accept the inherent inaccuracies of ring to cross hair alignment, concentricity of the ring and not least the manual alignment of the whole thing with your mark.
[EDIT]
If you use a cutter to make contact it gets even worse, because the diameter of the cutter changes over its circumference and is only ever full diameter at the very tip of the cutting edge

I have been using touch probe on my Mach3 for metal, but Mach3 is very unprecise,

There is actually nothing imprecise about mach, it is as accurate as the machine and the method of use.
I don't think you will get any better results using Linuxcnc, if you centre using this method. There are built in problems with it as I explained.

As for a probe, I made mine but quite honestly seldom use it. I tend either align by sight on pop marks or use an audible edge finder and do the maths myself if probing a hole

If I were using one a lot I would probably keep a close eye on ebay and get an industrial quality one as cheaply as I could

regards

I use a home made conductive probe. The tip is a ball bearing held in place by a magnet.

Here is a screenshot and video of hole centre finding with LinuxCNC, using a program posted by cradek ( 01262579508 ).



The probe works well for edge finding on metal but is not good for height. Here's an example of a non conductive probe that will probe edges and height. There are many examples out there of people who have made their own.
www.homanndesigns.com/store/index.php?ma...n0pc6ibfloirtrib33p5

Regards
hr