Vision System which verifies the correct part is present - Calibration / Verification

[caseright]

Hello everyone!
I am new to this forum and have a question on calibrating a vision system. We have resently installed a vision system on our assemly line not to measure a part but to verify that the correct part is being used. The plan is to measure the first part of every job and take a picture of that part. Then every part in the job is compared to that registered image. This system is going to be used on hundreds of different part numbers so master parts for all of the different parts is impossible. The system isn't intended to verify that all of the parts are in print just to verify that the part isn't dramatically different than the measured part.
We are TS 16949 certified and I'm not sure what the auditor's interpitation will be on this. The vision system manufacturer says they have not heard of anyone calibrating a vision system since it doesn't really measure anything. Does anyone out there have a system in place like this? Do you have it calibrated or do you have master parts that you periodically check on it? Any help in this matter would be greatly appreciated.

[BradM]

Hello there! Welcome to the Cove!

On this vision system, what kind of assessments are being made? Is it making some type of dimensional assessment? Does it check for depth or some other type of measurement? Does it display parameters, or print them out?

If it is just a camera, then I could not see the value of a calibration. If there are any measurements/dimensions that are being assessed, I would think you would need to assure the accuracy of that measurement system.

[Sidney Vianna]

Originally Posted by caseright

Do you have it calibrated or do you have master parts that you periodically check on it? Any help in this matter would be greatly appreciated.

From what you describe this "automated" visual inspection device is not "calibratable". However, how do you ensure that the system is warning you of defective parts? Can you "create" master no-go parts? I mean, parts that are slightly defective and the system should be able to identify and either sort or warn you about them? You could then run a test at a frequency that is appropriate and re-run such tests and keep a log.
Obviously this system must be able to be verified to it's "accuracy" and capability to detect non-conforming parts; otherwise, what would be the point of installing it?

[Teri]

Originally Posted by Sidney Vianna

From what you describe this "automated" visual inspection device is not "calibratable". However, how do you ensure that the system is warning you of defective parts? Can you "create" master no-go parts?

This is exactly what we do with our vision systems, they are not calibrated, but we have parts that are a no-go, tested once per hour.
It sounds like you may run many different parts across the vision system at the same time? (we don't). But maybe you could come up with some kind of rotating system to check it?

[caseright]

There are parameters displayed but they don't relate to inches or mm ete, they are measuring light pixels. I know about how much a part has to change dimensionally before it will fail so maybe one set of master parts that cover both limits would be the way to go?

[BradM]

OK. So you have a "master" part, that you set this dimension equipment to. You have set up the master dimension equipment, look at the other parts, then you make a thumbs-up/thums-down assessment.

I mean, I guess Teri and Sidney may have a little better feel for this than I. I have seen a lot of dimensioning equipment, and much of it requires some level of standardization to assure proper dimensions are obtained.

Have you contacted the mfg. of the equipment? They should be able to let you know what kind of verification is required.

[caseright]

The mfg said they have never heard of anyone calibrating a vision system because it is technically not a measurement device and there are so many factors that affect it. Even though I'm not measuring a part per print shouldn't I be able to set up some parameters that I want the system to reject and ensure it is doing what I want it to do by running the master parts through it and making sure it will reject them?

[Sidney Vianna]

Originally Posted by caseright

shouldn't I be able to set up some parameters that I want the system to reject and ensure it is doing what I want it to do by running the master parts through it and making sure it will reject them?

Yes, you should. How else you would know if the equipment is working properly? The manufacturer of the equipment has to have acceptability tests. And they would have to be customized for the parts being inspected.