Packaging Metal Detector Suppliers & Manufacturers

How packaging metal detectors work and what they detect

A packaging metal detector uses a balanced coil system to detect the presence of metallic objects in or on packages passing through its aperture. The detector consists of two receiver coils and one transmitter coil wound around an aperture; when no metal is present, the receiver coils are in electrical balance; a metallic object passing through disturbs this balance, triggering a signal that activates the rejection system. Metal detectors detect: ferrous metals (steel, iron) — the easiest to detect; non-ferrous metals (aluminium, copper, brass) — slightly harder to detect; stainless steel — the most difficult to detect, requiring advanced balancing technology, particularly in food applications where stainless steel is commonly present in processing equipment and packaging (foil lids, foil-laminate pouches). For stainless steel detection in food, the minimum detectable sphere diameter is typically 1.5–3.5mm depending on aperture size, product effect, and whether conductive or wet products are present. Food safety standards: BRCGS (BRC Global Standard for Food Safety), SQF, FSSC 22000, IFS Food, and other GFSI-recognised food safety schemes require food manufacturers to have validated metal detection procedures as part of their food safety plan. HACCP critical control points for metal contamination typically include a metal detector or x-ray inspection system at or after primary packaging. BRCGS requires a documented test protocol (standard test piece size and material, test frequency, rejection verification) and maintenance records.