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Author Topic: Need some help, using a digitizing probe to find the center of a bore  (Read 4515 times)

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i am soon going to be working on a project where I have to put a digitizing probe in the spindle and find the center of a bore.  Its a 5 axis trunion style machine.  going to put a ring in the 5th axis chuck and I need some help writing a macro in mm that will move x and y to find the center of the ring.  In essence find the center of the 5th axis.  Is this do able?  My thoughts are to move the y until the probe triggers then have Y move in the opposite direction untill it triggers again.  Then move back to center, then in X same routine.  I imagine that this would have to be done a couple of times in a row to find true center.

Offline Hood

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Re: Need some help, using a digitizing probe to find the center of a bore
« Reply #1 on: January 21, 2011, 09:55:38 AM »
Have a look on the Show and Tell section of the forum at JHChoppers Bridgeport thread as I am sure he posted macros for probing in that way.

Hood

Edit, here it is
http://www.machsupport.com/forum/index.php/topic,13365.110.html
« Last Edit: January 21, 2011, 09:57:57 AM by Hood »

Offline Tweakie.CNC

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Re: Need some help, using a digitizing probe to find the center of a bore
« Reply #2 on: January 21, 2011, 12:46:11 PM »
Hi Fixittt,

Can't say that I am a great fan of this but you may also wish to consider looking at 'Mach Std Mill'  http://www.calypsoventures.com/downloads/machstdmillrelease.html
All the probing routines you should ever need seem to be included plus extremely colorful screen sets etc.

Tweakie.
Success consists of going from failure to failure without loss of enthusiasm.  Winston Churchill.
Re: Need some help, using a digitizing probe to find the center of a bore
« Reply #3 on: January 21, 2011, 09:14:24 PM »
Be careful with probes to find circle center. I have been doing this for a while with a probe from IMserv. The other day I decided to check the accuracy of the center and found quite an error.

If you run the probe once and find center, then rotate the probe 90 degrees and do it again you may have several thou error.

I talked to Fred Smith of IMserv and he said that was expected of a probe- they are not made to be concentric and you need to first probe a known reference and set compensating values for the error.

I bought a Wildhorse Innovations probe. It has a much stronger spring, and is designed to let you make an adjustment for centering. I now have mine so Im within 1 thou of true center.

Offline BR549

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Re: Need some help, using a digitizing probe to find the center of a bore
« Reply #4 on: January 22, 2011, 02:13:37 PM »
ANYtime a precision probing operation is started the first thing to do IS verify the Probe center.

Alway mount the probe in the same position in the spindle. AND rotate and lock  the spindle to the same spot each time.

Mach can probe in XYZ and A. Not sure of the other 2(b,c)

There are several methods that can be used 3 point or 4 point are the most common.

There is an example of the 4 point method in one of the Mach manuals AND examples of probing macros here at this website.

(;-) TP



Re: Need some help, using a digitizing probe to find the center of a bore
« Reply #5 on: February 06, 2011, 09:24:57 AM »
I took a look at the link Hood suggested and I love it!  So I downloaded all the buttons and scripting.

Now for a stupid question,

I am trying to setup the vb scripting for each of the buttons.... I dont understand how the vb scripting should be done for each button.  Here is the snippet from the thread......  can someone help me to understand how exactly each button script should be laid out?

Here are the buttons that I used, not the best buttons however, but a starting point if you choose...  Also, if you look at the M1200 Macro, each button is processed via the switch statement below.  This allows ALL the tool probe code to be in 1 file, instead of spread across several.

To use, just add the Macro and a VB Parameter to each of your buttons.

Your Mach3 Button Code might look like this for "X-"  M1200 P6
 

 
    ' Process the selected tool probe button
    buttonId = Param1()
    Select Case buttonId
        ' XYZ Buttons
        Case 1  buttonPosXNegY  ' X+Y-
        Case 2  buttonNegY      ' Y-
        Case 3  buttonNegXNegY  ' X-Y-
        Case 4  buttonPosX      ' X+
        Case 5  buttonNegZ      ' Z-
        Case 6  buttonNegX      ' X-
        Case 7  buttonPosXPosY  ' X+Y+
        Case 8  buttonPosY      ' Y+
        Case 9  buttonNegXPosY  ' X-Y+
       
        ' ID and OD Functions
        Case 10 buttonCircleID  ' C-ID
        Case 11 buttonCircleOD  ' C-OD
    End Select

Offline alenz

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Re: Need some help, using a digitizing probe to find the center of a bore
« Reply #6 on: February 06, 2011, 05:16:36 PM »
Its as shown in his example.

'Your Mach3 Button Code might look like this for "X-"  M1200 P6'

The button will call Macro M1200.m1s and the P-parameter will tell the macro which button was pressed. The P will be Param1 (), (a Q and R would be Param2 () and Param3 () respectively).

JHChoppers added a screen4 screenshot showing a sample entry in a later post.
HTH,
al