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### Author Topic: Mirror probing  (Read 1967 times)

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#### BR549

• 6,952
##### Re: Mirror probing
« Reply #30 on: April 02, 2019, 10:23:09 AM »
Giving this a bit more thought here is how I would do this project.

Mount the barrel in teh 4th and center the probe over teh barrel in Y axis.

Move teh X point to teh start point of teh probing routine. Probe tehesurface in Z and set teh Z to the radius of the barrel at that point.

Next probe in X for the distance of the rib to be duplicated. This gives you a single line contour of teh barrel.

Save out teh points and import them into CAD.

From CAD create a angular array from teh end view. The total angle would be teh wide of teh rib section.

Rotate teh points 180 degrees to create a negative of teh barrel form.

That would give you an easy set of points to create a 3d surface from. ( Point Cloud)

Export teh points out or convert the points into a surface file.

Then from a 3d CAM create a 3d toolpath to recreate the barrel contour.

Just a thought , (;-) TP

#### DonMarkey

• 115
##### Re: Mirror probing
« Reply #31 on: April 14, 2019, 05:42:16 PM »
Wow. Lots of food for thought. I am thinking a casting and then straight one to one duplication is going to be my easiest approach. Then the probing with a stylus matched to ballmill diameter would work?
Don

#### joeaverage

• 6,384
##### Re: Mirror probing
« Reply #32 on: April 14, 2019, 05:53:44 PM »
Hi,
yes that would work but you can omit the casting step.

If you probe the barrel with a matching probe, save the data, then the ball mill can follow the path from the previously
stored data.

Craig
My wife left with my best friend...
and I miss him!

#### DonMarkey

• 115
##### Re: Mirror probing
« Reply #33 on: April 14, 2019, 06:09:31 PM »
So I am overthinking this?  If I probe the centerline, then probe again .020” off center and so on I can use that as my step over and convert the z+ z-?  What am I missing?

#### joeaverage

• 6,384
##### Re: Mirror probing
« Reply #34 on: April 14, 2019, 06:38:09 PM »
Hi Don,

Quote
If I probe the centerline, then probe again .020” off center and so on I can use that as my step over and convert the z+ z-?  What am I missing?

That is the essential idea....you are not missing anything.
Most CAD/CAM programs have a function that converts a set of points, or point cloud, to a Gcode toolpath. It is still
the same idea but is automated to produce the Gcode. You could for instance probe at 0.02 stepovers but to get the
accuracy you might decide to mill at 0.005 stepovers, the CAD/CAM program allows that.

Carig

My wife left with my best friend...
and I miss him!

#### DonMarkey

• 115
##### Re: Mirror probing
« Reply #35 on: April 14, 2019, 06:56:45 PM »
Now you are assuming I have or even know how to use cad/cam. Haven’t used that since the late 80s. I use conversational cnc on one mill or write g code manually for the mill I converted to Mach3 right now.  But I’m learning.
Thanks
Don

#### joeaverage

• 6,384
##### Re: Mirror probing
« Reply #36 on: April 14, 2019, 07:26:52 PM »
Hi,
CAD/CAM is not absolutely essential to making a probe point cloud work it certainly helps. It may well be that the effort
required to master one of the programs out there is a greater effort than casting the part as you have done before.

Fusion360 is a very capable CAD/CAM program available free from Autodesk. If you have a 64 bit PC and OS download it
and try it out. I suspect it will do as you require. The only question is whether you are prepared to stump up the time
to learn it?

Craig
My wife left with my best friend...
and I miss him!

#### joeaverage

• 6,384
##### Re: Mirror probing
« Reply #37 on: April 15, 2019, 01:24:12 AM »
Hi Don,
thinking a little more about your situation. I suspect that learning to use a CAD/CAM may be a hurdle.
Evidently you are quite capable of conversational programming and manual programming.

I myself use MillWizard from NFS (\$75), it adds what amounts to conversational programming. There is one feature of
that program that may appeal to you. Its the 'Polyline' feature. You program a series of points with either lines or
arcs between each point and MillWizard will generate the Gcode.

I have attached a couple of pics that might explain it a little better. The first pic is where I have programmed a number (5)
points (X, Y coordinates) with a straight line in between each. The second pic is the toolpath that MillWizard generates.
There are other options as well, tool offsets, direction of cut etc. While it is tedious to program in the points its perfectly
doable and in fact very simple.

Such a method would not be practical if you had a point cloud of a thousand points but probably useful up to 100 points.

Download a copy and try it. As a demo you can't save the Gcode but is in all other ways fully functional. The advantage of
MillWizard is that you can be producing Mach compliant code within 1/2 an hour.....its so straight forward.

Craig
My wife left with my best friend...
and I miss him!

#### DonMarkey

• 115
##### Re: Mirror probing
« Reply #38 on: April 15, 2019, 07:59:02 PM »
Thanks I’ll look into it.
Don