Regularity connects inspection technology to product kind and size.
According to Todd Grube, product manager for inspection systems at Heat and Control, physical dimensions and orientation, particularly of conductive objects, might affect the results of a metal detector inspection. It can also be used to ascertain the kind of technology.
Manufacturers are required to ascertain whether the metal detection technology they use in their goods is limited to CEIA metal detectors, multi-frequency, or multi-spectrum technology.
The secret is to operate with a range of frequencies in order to correctly match the system with the product type and size.
Fortress Technology’s Steve Mason, sales manager, “changing the frequency of operation to minimise the effect” is frequently the best course of action.
Selecting one frequency over another, however, occasionally becomes a trade-off.
He issued a warning: “The drawback of doing this is that it may impact the ability to find different metals.” Because the lower end of the frequency is more sensitive to the magnetic effects of the pollution, lowering the frequency improves the capacity to discover ferrous metals but reduces performance when it comes to finding non-ferrous metals. Similarly, if the frequency increases, the opposite occurs; the ferrous detecting abilities are restricted, but improved non-ferrous detection
Modern metal detectors address this issue by simultaneously using several frequencies. The MSF metal detectors from Mettler Toledo use two stages—frequency and phase—to concurrently use high and low frequencies.
“This eliminates the input from mixes of high and low frequencies,” stated Camilo Sanchez, Mettler Toledo’s product inspection product manager for metal detection. As a result, the product signal is effectively eliminated, making it possible to identify considerably smaller impurities.
For improved inspection, vision technology can be used with metal detection. Although most systems have concentrated on measuring differences in height or colour, EyePro System developed its Multi-Eye technology over several years to identify flaws on a product’s surface.
According to Erica Vannini, sales and customer service representative for EyePro System, “Our systems can inspect the quality of the products and identify defects that are often not detectable by other technologies.” In order to identify the foreign body, it takes a picture of the product at several wavelengths using spectroscopic and imaging technology. “Consider a piece of white plastic on a pizza with mozzarella cheese.”