Test Pieces for Metal Detectors

Hi,

Just wanted to ask the required size of metal pieces based on the regulation to be used in testing the efficiency of metal detectors.

Your help is of great help. Thank you

Depending on the country you are in, you would have to look at their regulations on legal limits for metal in product. We use 2.0 mm SS, 2.0 mm NFe and 1.5mm Fe. Those are a lot smaller than what is legally allowed and my inspector asked me why we didn't get bigger pieces. My reasoning was that we produce flour, and I want to be absolutely sure nothing bigger than that is getting through. 

Basically your MD should be able to detect the size you allow or is legally allowed. 

The critical for metal test piece is 1mm for Fe, 1.5mm for NonFe and 2mm for Sus

Hi,

Just wanted to ask the required size of metal pieces based on the regulation to be used in testing the efficiency of metal detectors.

Your help is of great help. Thank you

Hi yaba,

The MD you use should have a specification (for a given set up) regarding sensitivity, typically defining the smallest (Fe/non-Fe/SS) sphere  "detectable" when passed thru the magnetic field at the worst signal location (typically the central axis). So this sphere dimension can be used to test the "efficiency".

The general practical efficiency will particularly relate to factors such as food matrix, eg wet/dry, MD aperture height and sample shape/orientation if non-spherical, eg needle-like/vertical/horizontal.

Hopefully, the MD size detection limit (LOD) for yr food matrix will be less than the Regulation.