Magnets in the plastics industry
Metal contamination is a significant problem in the plastics industry as it can damage equipment such as injection moulding machines, extruders, screens, mixers and crushers, moulds, dies and other key components. This leads to a reduction in production and an increase in maintenance costs. To avoid these drawbacks, different magnetic detection systems are implemented at various stages of the production process.
Plastics are supplied in various forms, such as granules, powder or chips, whether they are new or recycled raw materials. It is essential that these materials are free of metals and unwanted foreign bodies. To ensure the purity of the material, magnetic filters and magnetic filter bars are used, which detect and remove any type of metallic particles.
Sources of metallic contamination
Metallic contamination can originate from different sources. These include wear or damage to machines during processing or the presence of metallic particles in the recycled raw material. An accurate magnetic system is able to remove these contaminants before they cause problems in the production process.
The main plastics manufacturing processes include injection molding, extrusion, vacuum or pressure forming, and rotational molding. In these processes, the presence of unwanted metal parts can cause nozzles and spray openings to become clogged, affecting plastic dosing and potentially leading to the rejection of entire batches of products. In addition, a nozzle blockage requires disassembly, cleaning, or even replacement, resulting in downtime and additional costs.
Consequences of metal contamination
The main consequences of metal contamination in plastic production include:
Production downtime.
Machinery damage.
Rejection of the final product.
Undesirable product characteristics.
Plastic granulate processed in extruders often contains iron particles that can damage the extrusion technology, leading to high maintenance costs and downtime. To prevent these problems, the use of magnetic systems at various stages of the process is recommended.
Magnetic solutions in the plastics industry
To remove even the smallest ferromagnetic particles, a filter with magnetic bars is the best solution. These magnetic separators, made of neodymium magnets, generate an extremely strong magnetic field that can capture tiny particles, even one micron in size.
Neodymium magnetic separators are strategically placed in the manufacturing process, for example, under the hopper containing the plastic granulate before it enters the extruder. In this way, not only is contamination detected, but the raw material is also immediately purified, avoiding problems in production and guaranteeing the quality of the final product.
Another effective system is the pneumatic self-cleaning magnetic filter, which stops the flow of material during the cleaning procedure, optimizing process efficiency.
Benefits of using magnets in magnetic separation
Installing magnetic separators offers the following benefits:
Reduced extruder repair costs.
Reduced production downtime.
Possibility of increasing the use of plastic regranulate in manufacturing.
When contamination is detected in a production batch, it is quarantined for investigation. In these cases, specialized technicians analyze the problem and apply magnetic solutions to eliminate the contamination and avoid future problems. Companies such as Magnetplastic offer prevention technologies to ensure raw material purity and efficiency in plastic production.