What you see is what you get is a term that is strained when it comes to metal detectors. Most food metal detectors either deliver feedback in numerical displays or higher level of graphical display that interprets absorption / disturbance of the electromagnetic field.
The working principal of any food metal detector is based on the generation of a electromagnetic field. Food products (packaged or raw) are conveyed through the magnetic field (head aperture) and then disturb the field. An onboard processor with the necessary algorithms ‘learn’ the natural electromagnetic disturbance pattern of the product and isolates it electronically. And any further disturbance due to increased absorption triggers an alarm (or reject) eg. ferrous contaminate like a screw or bolt.
Although most food metal detector will allow you to set this up automatically, establishing the thresholds for what normal = good or not normal = metal contaminate, the boundary between both is what drives effective inspection or problematic inspection (where the system rejects on false positives). In most cases the operator has to manually adjust the boundary following an automatic system training / set-up in order to produce reasonable operation with low false positives.
Given the need for manual operator intervention in initial set-up or through production as product change affecting the natural electromagnetic absorption, the quality metal detector operator-machine-interface is important. Numerical displays are the most difficult to adjust, graphical displays showing absorption level are better, but newer operator display visually displaying the exact absorption pattern are the best.
Visual displays showing electromagnetic pattern absorption allow operators to see exactly what is happening and how the changing product is varying. When initially setup using these types of display a rectangular boundary box is automatically drawn around a curving line (which represents the absorption signal). With visual displays that also include ‘touch screen’ functionality, the boundary box can easily be adjusted for both size and angle around the curving line increasing its size until the curve line representing the natural absorption consistently remains within it (reducing instances of false positives). The advent of these types of visual display from numerical displays can be compared to first generation Blackberries to the latest iPhone in terms of ease of use and functionality.
Note that whether a metal detector rejects correctly or not (positively or on false positives), work is created for your Quality Assurance department as each rejected product must be processed through a procedure based on food safety practices. Reducing false positive is directionally better for any operation seeking to run efficiently. The improvement in functionality greatly reduces operator errors and operating your food metal detector with a high instance of false positive.
Graphical representation in operator interfaces have been shown to lead to better understanding of machine operations compared to numerical displays (numbers). Studies show that humans process and manage information better when the gap between interpretation and visualization is reduced. Improving this process by using food metal detectors that carry this feature improve operator – machine interaction and overall production results.
View our Rental Program or contact us for more details on how we can help your business!