Calibration of spring loaded test fixture

[al40]

Hi all,

I am working on a supplier issue between my plant and our supplier the issue is our incoming inspection is rejecting the parts and the supplier is passing parts they are using the exact same fixture which is spring-operated to test parts to ensure the latch is released. Neither of the fixtures has either been validated or calibrated to my knowledge and not even sure how they could be unless you remove the torsion springs and tested them individually.

Any suggestions on how to proceed? My thoughts are design a fixture that you can calibrate and ensure repeatability.

Thanks,
Al40

 

[Jim Wynne]

... the issue is our incoming inspection is rejecting the parts and the supplier is passing parts they are using the exact same fixture...

If one fixture is passing the parts and the other is rejecting them, they're not exactly the same.

Neither of the fixtures has either been validated or calibrated to my knowledge and not even sure how they could be unless you remove the torsion springs and tested them individually.

Given the information at hand, it's not possible to offer comprehensive advice as to how you should proceed. In my experience, inspection fixtures are created either because of anticipated risk, or something bad has happened. All inspection fixtures should (a) have a documented theory of operation (what the thing is expected to accomplish and how the thing accomplishes it) and (b) be validated to confirm the theory. Without knowing more, I'd probably test both fixtures with known good parts and known bad ones. An attributes gage should be able to detect bad parts and pass good ones 100% of the time.

 

[al40]

If one fixture is passing the parts and the other is rejecting them, they're not exactly the same.


Given the information at hand, it's not possible to offer comprehensive advice as to how you should proceed. In my experience, inspection fixtures are created either because of anticipated risk, or something bad has happened. All inspection fixtures should (a) have a documented theory of operation (what the thing is expected to accomplish and how the thing accomplishes it) and (b) be validated to confirm the theory. Without knowing more, I'd probably test both fixtures with known good parts and known bad ones. An attributes gage should be able to detect bad parts and pass good ones 100% of the time.

Thanks Jim, my thoughts exactly.

 

[Mike S.]

Yeah 2 test fixtures should have never been released without verifying they both perform the same, and a documented procedure for periodic maintenance and calibration/verification. It's just asking for trouble to do otherwise.

 

[BradM]

Is there any way you can have the same operators (from your supplier and from your inspection) perform tests on the two test setups? Do you have a singular test procedure that both use?

Is this something that could be shipped? Take a sample of... 10 parts and have your supplier test them and have your inspection test them on Test setup 1 and then on test setup 2. Then compare each test setup across different operators. The differences you are observing may be in the test setup, variance among testers, or both.

 

[dwperron]

Hi all,

I am working on a supplier issue between my plant and our supplier the issue is our incoming inspection is rejecting the parts and the supplier is passing parts they are using the exact same fixture which is spring-operated to test parts to ensure the latch is released. Neither of the fixtures has either been validated or calibrated to my knowledge and not even sure how they could be unless you remove the torsion springs and tested them individually.

Any suggestions on how to proceed? My thoughts are design a fixture that you can calibrate and ensure repeatability.

Thanks,
Al40

Is there some way to get a load cell or force gauge into the fixture?