Conventional unfilled polymers will not be detected by metal detection systems. Due to the low density of these materials then, depending upon conditions, it is often extremely difficult for an X-ray system to differentiate them from food products and reliably detect them.
Engineered additives and additive blends are incorporated into the polymer during the compounding stage. Some additives focus on metal detection performance, whereas others are specific for X-ray detectability.
A heated cathode generates electrons, while a high voltage between the cathode and anode accelerates these electrons towards a tungsten disc. Upon impacting the tungsten disc, the electrons are slowed down and subsequently generate X-rays.
The X-ray beam passes through the product(s) and is absorbed at differing rates determined principally by product/foreign body thickness and density. The transmitted beam is detected at the opposite side by an array of sensors and thereafter, via several steps, the signal intensity is converted to a grey value. The more X-rays that are absorbed by a particular material, the darker shade of grey it will appear on the final image and the more chance of the machine detecting it against a food product.
The ability to be detected and rejected by an industrial metal detection system, designed to sense to varying degrees ferromagnetic, non-ferromagnetic and non-magnetic metals.
The ability to absorb sufficient x-rays such that there is a noticeable difference in intensity (grey value) in the final image between a foreign body and food product. When metal/x-ray detection systems are used effectively in the food/pharma processing industries, these properties help to reduce foreign body contamination by sufficiently detectable materials.
Metal detectors are perfect for detecting metal foreign bodies, but are limited to this type of material. X-ray inspection technology has the capability to detect a much wider range of materials/contaminants than metal detectors, including metals but also the like of glass, ceramic and bone.
Any applications where there is a risk of small fragments entering the production flow e.g. tags, straps, pallets, seals, conveyor belts, cable ties etc. These fragments need to be detected to minimise the risk of them entering the consumer chain.
Radical Materials Ltd
Unit 10, Rassau Industrial Estate, Ebbw Vale, Gwent NP23 5SD, United Kingdom
+44 (0) 1495 211400 info@radicalmaterials.com
SCOPIC® & KONDUCT® are registered trademarks of Radical Materials Ltd. AIRSENTIAL® is a registered trademark of Radical IP Ltd.
Radical Materials is presently working on a project aimed at developing performance polymer compounds to provide EMI/RFI shielding solutions in moulding/extrusion applications. This project is being undertaken with financial support from the ERDF via the SMARTCymru 2014-2020 West Wales and the Valleys Operational Programme.