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Vision CMM Calibration

jmh90

Plastic
Joined
Nov 19, 2018
Is there a good general procedure when it comes to calibrating a vision CMM? I've done a lot looking on the internet, but most things I've found are for probe based CMM. Any info would help.
 
More information needed.
You have the normal cmm errors plus the camera's optics errors and then the edge detection routines.
Not sure what you are trying to do.
There are nicely printed masters you calibrate against but sometimes the real world is different.
It's good idea to calibrate on know parts of the shape and style you make.
Just simply trying to make the document for your ISO cert is fairly easy.
Bob
 
I work for a company the makes and sells manual, vision CMMs So non-CNC, non-contact CMMs. We don't exactly have an in-house calibration procedure that we use before shipping the machines to the customers, just whatever one guy was taught years ago. Basically I'm not sure if what he does is correct, good, etc.

The measure software we have is Metlogix M3, in which we perform Circle, Stage, and FOV Calibration before shipping the machines.

Does this "procedure" seem accurate or enough to say that the machine is working properly?
 
ISO 10360-7 for accuracy verification. Calibration adjustments are dependent on the make/model/software.
 
Most straightforward for the x-y plane is a glass grid with calibrated points. Mitutoyo has am accredited calibration center that can calibrate these. This can check x,y, and angular accuracy all at once.

Or if you use a calibrated scale (like chrome on glass. Mitutoyo sells these also), check each axis individually in several paths, then using two location spots on the scale (like decimal points) place the scale at approx 45 degrees in the xy plane, read xy cood. at each end, then rotate the scale 90 degrees so it is approx 45 degrees in the other direction and read the same two points on the scale in xy coord. From this you can determine the difference in squareness that the CMM would make if drawing a box. Z axis is most easily tested with gauge blocks.

Or hang a mirror on the lens and do it all with a laser.
 








 
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