[AIB ICE Chips] Answers to Your Toughest QA Questions

Q. We recently had a customer tell us that we did not have to run all three types of test pieces when we check our metal detector. They said that since the stainless steel piece is the hardest to find, we can just check for it and the metal detector will automatically find the others. Is this OK? It would save time.

A. To answer your question simply, NO! You will not be OK if you only run a stainless steel test piece.

Now, to answer your question in a more detailed way: Recent data provided by a major manufacturer of metal detection equipment reveal that even the current methods of running one test piece for ferrous, nonferrous and stainless steel through one at a time likely are resulting in inadequate testing.

Not only has meteal and foreign object detection technology advanced considerably, our understanding of the optimum performance issues associated with the equipment also has increased.

Many current testing protocols for detection equipment require that three test blanks — each containing one of the three metals — be placed on or in a package of product and run through the detector. If the blanks are rejected, the test is considered successful.

However, a more relevant test of the unit’s performance involves using three of each of the test pieces. One test piece should be placed on a leading edge of the first package, a second piece placed at the center of the next package and a third piece placed on the trailing edge of the third package.

Since metal contamination usually results in a cluster effect, it makes sense that — in order to have confidence that the detector can recognize and successfully remove a series of contaminated packages — a test method that mimics a cluster of contaminated product for each type of metal is ideal. This would require nine test pieces for each verification check.

I encourage anyone who is responsible for metal detectors to learn as much as possible about the construction and operation of the units they are using. Most manufacturers have technical and non-technical manuals and brochures and other resources available to customers. Contact the manufacturer of your devices and request that they assist in the training and maintenance of the units used in your facility.