Critical Limits for Metal Detectors

We have purchased 2 new Fortress Vertex Metal Detectors to use on our production lines.  Our current metal detectors are spec'd for 1.0, 1.0 & 1.5 detection.  The new devices are only spec'd for 2.0.  We have tested the new devices and they are detecting the 1.0, 1.0 & 1.5 and we intend to test them at these levels.  

My question is, if we are testing them at the lower levels do we have to raise our critical limits to 2.0 because of the equipment spec's or can we keep our critical limits at the level that we are testing them at?

We have purchased 2 new Fortress Vertex Metal Detectors to use on our production lines.  Our current metal detectors are spec'd for 1.0, 1.0 & 1.5 detection.  The new devices are only spec'd for 2.0.  We have tested the new devices and they are detecting the 1.0, 1.0 & 1.5 and we intend to test them at these levels.  

My question is, if we are testing them at the lower levels do we have to raise our critical limits to 2.0 because of the equipment spec's or can we keep our critical limits at the level that we are testing them at?

In many cases, the sensitivity is related to the aperture / type of product matrix / cost of unit.

i would suggest to make sure you are not getting any false positives/negatives at the "better than spec" settings.

i would also check with the supplier if they have any objection to these stricter settings.

If above ok and everything else is being equal, the choice is probably up to you and what is logically required by USDA/FDA/your particular product/customer(s). Presumably the latter's preferences will be the lower limits. :smile:

Hi QANewHopeMills,

Assuming no change in process, I noticed from yr earlier thread that the lowest limits mentioned are not characteristic for yr industry.

http://www.ifsqn.com...mit/#entry86374

There may be an operational reason for this.

Or you may find yr new machine is simply better than yr competitors, eg more discriminating. Hope so.