Sheet in PEEK FG UD 1220x610 mm gray

A sheet in PEEK FG UD is detectable PEEK for the food industry. The grade is filled with an additive that lets plastic parts, or fragments of them, be picked up by both metal detectors and x-ray systems in the production line. The idea is simple: if a scraper or a guide breaks, the piece has to be found by the detection before the product reaches the customer. The requirement shows up more and more often in audits, and this is in practice the way to solve it on the plastics side.

FG stands for food grade. The material meets the FDA requirements and EU 10/2011 for plastics in contact with food, which means the parts can sit in direct contact with the product.

The base polymer is PEEK, one of the toughest engineering plastics available in semi-finished form. Maximum operating temperature is 260 °C, the flammability rating is V0 according to UL 94, and the material stands up to chemicals, hydrolysis and hot steam; that steam resistance is exactly what makes PEEK the first choice where parts are cleaned with hot steam or aggressive CIP media day after day. Creep resistance is good even at elevated temperature, so preloaded joints hold their torque better than in simpler plastics. Wear resistance and stiffness are also in the top tier among engineering plastics, which is why thin scrapers and guide strips in PEEK keep their shape and their edge far longer than in POM or PA.

The density of 1.71 g/cm³ reveals the filler content; unfilled PEEK is around 1.31. The detectable additive therefore gives a noticeably heavier material, and it also affects the mechanical properties somewhat compared with unfilled PEEK FG; factor in the weight when the part sits in fast moving assemblies. Exact strength values are in the data sheet.

The detectability works in two ways. Metal detectors react to the additive in the material, and x-ray systems see the difference in density against the product; which fragment size is actually caught depends on the sensitivity of the detection equipment and should be verified in your own line before the part is approved. It is a good idea to document the verification in your own-check program; auditors often ask for exactly that record.

Typical parts are scrapers, guides, slide strips, nozzles, dosing parts and wear parts in filling and packaging machines, as well as components in pharmaceutical production where the same detection requirements apply. In HACCP work, detectable plastic parts often count as a directly risk-reducing measure.

Wear parts in a food environment are often replaced on time rather than on condition, because nobody wants to find the cause afterwards. With a detectable material the consequence of an unexpected failure becomes manageable instead of ending in a recall, and that changes the whole risk calculation around the part. The reasoning is familiar from detectable knives and scrapers on the steel side, and the plastics side is now following.

Against standard PEEK FG the choice is a question of risk. If the part sits where a fragment can end up in the product flow, you choose the detectable grade; if it sits outside the product zone, ordinary food grade is enough. The combination of 260 °C, V0 and detectability is otherwise hard to put together in any other material.

Machining is forgiving for a high performance plastic. PEEK is turned and milled with carbide tools and good cooling; rough machine, let the part rest and finish machine to final dimension when the tolerances are tight. For larger series it pays to rough cut blanks out of the sheet before milling, so the clamping surfaces come out even. The 1220x610 mm sheet format suits milling scrapers and guide strips straight from the sheet.

Do you have detectability requirements in your own-check program? We will help you choose the right PEEK grade and thickness.