Contaminant detection in the plastics-processing industry

From blocking hot runners to crashing extruder screws or breaking blades in shredders, metallic contaminants can cause many problems for plastics processing. We have the right contaminant detectors to prevent damage to machinery and production downtime.

Sesotec specialises in systems for industrial contaminant detection and has more than 40 years of experience in the plastics industry.

We provide a complete range of leading technology that includes metal detectors and magnet systems for the reliable detection and removal of contaminants in a wide variety of applications. Our systems can target ferrous metals, stainless steel and non-ferrous metals, such as aluminium, copper or brass − regardless of whether the metals are magnetic or not, coated, painted, loose or embedded in material.

Sesotec's strengths

over 40 years of experience and reliability

Personal support in the after-sales area


Long-term reliability for spare part supply



Why is contaminant detection and removal important for processing plastics?

Machine protection is key, as costly equipment − including injection-moulding machines, blow-moulding machines, twin- and single-screw extruders, and calenders − are at the heart of plastics processing. The aim therefore is to protect machinery from damage to prevent expensive repairs and production downtime. Particular focus is placed on the detection and removal of metallic contaminants, as they can quickly cause blockages and damage.  

Quality assurance is another important factor. Metal particles in the final product are not the only reason for compromised quality. Blockages and tool damage can also result in defects from too little or too much injection of the materials. Metal detectors ultimately help to detect bead wire breaks.

Product example PROTECTOR

What kinds of contaminants could appear?

Metal particles made of iron, stainless steel or copper which are hidden among the plastic granules are the most common type of contamination in the plastics-processing industry. They can come from a variety of sources:

  • Contaminated input materials (granules, recycled materials, additives)
  • Wear and slough from machines or pipes
  • Open material containers that contaminants can enter
  • Personal items belonging to staff (pens, jewellery, etc.


Where do plastics-processing plants use our machines?

Common applications include the following:

  • Incoming goods inspection of granules and additives after delivery
  • Inspection of granules in conveyor pipes
  • Inspection of granules and additives right at the material inlet of the processing machine
  • Inspection of production waste and other recyclable parts before shredding/recycling
  • Inspection of finished plastic parts on a conveyor belt before packaging


As you can see, we support you in all steps of the process. We would be happy to advise you personally to find the right solution for your need together.


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