The whole of the plastics industry can effectively be split into two separate parts. There is plastic processing which involves raw materials and virgin plastics being combined and then processed into various plastic products such as household plastic goods or sturdy plastic crates that you might see used in the industrial sector. They might even be processed into plastic bags and packaging.
The materials and plastics used for these purposes have seen a steep increase in price in recent times, perhaps due in part to the recycling industry becoming ever more popular and a drive and emphasis on stronger green practices. The industry itself usually operates from plastic processing plants or specialist recycling plants.
Quality is of paramount importance to any processor of plastics and there are a host of things that can prove challenging in the quest for the best end product possible. One of the concerns is that of metal contamination, which unless measures are taken to prevent it, can be introduced at various stages of production and have a major impact on the overall quality of the product. It’s not just the products that are at risk from metal contamination, even the production equipment itself is at risk, with damage possible along with the costs of repairs and significant time loss. Injection moulding equipment, crucial in many processes can be very expensive to repair and to fit with new injection barrels or screws and the costs can simply add up.
With the recycled plastic processing industry growing, it has never been more important to ensure that the separation process is as effective as possible. Eliminating traces of metal as early as possible in the process, ultimately means that by the time the product has been sent from granulation to injection moulding, it has already been cleaned and reduced the potential of equipment damage.
Bunting have produced (specifically designed and manufactured for the plastic processing industry) a range of magnetic separators. These separators, along with the knowledge and advice that the team at Bunting can offer can go a long way to ensuring that products are delivered in the most cost effective way whilst maintaining high quality.
Magnetic Separators Designed for the Plastics industry
Cartridge/Tube Magnets – These are shaped like a rod and are classified as permanent magnets. They are designed to remove fine ferrous metal from both free flowing dry and wet products. As the main magnetic component for a host of other magnetic separators, they are primarily used as tools for inspection.
Grate Magnets/Grid Magnets – These are very commonly used within the plastics industry and their task is to remove fine ferrous metal from free flowing materials. They are constructed using Bunting’s magnetic cartridges and can be purchased in square, round and rectangular options. Usually, you will see them placed inside the hopper of an injection moulding machine.
HF Series Drawer Magnets – Whether flowing by gravity or by mechanical flow inside enclosed lines, these magnets are designed to capture ferrous debris from free flowing (dry) plastic products. Featuring Grate magnets which are stacked, this produces a handle system that is easy to inspect as well as allowing for maximum separation. When opting for standard models, you can choose between a number of different configurations, including different cleaning methods such as fully automatic and manual pneumatic.
FF Drawer Magnets – These magnets have been specifically designed to work with the high temperatures associated with injection moulding equipment. Made from Neodymium rare earth magnets, they are perfectly suited to removing tiny metal particles from free flowing dry products. If headroom is at a premium, it might be better to use a low profile drawer magnet which has all of the same attributes but provides more space than the standard FF drawer magnet.
Plate Magnets – These magnets can be used to capture both tiny pieces of ferrous metal and larger metal contaminants from free flowing materials. They can also be placed either above or below the product flow. Unlike grate magnets, which are likely to get clogged when using moist or damp materials, plate magnets are ideally suited here. For situations when the flow is enclosed, there is an option to use a plate in housing. Just as with their HF Series cousins, these plate magnets feature both manual and pneumatic clean versions. Suspended plate magnets are also available and these are best suited in situations where metal contamination is low and require little cleaning.
In-Line Magnet Range (Gravity, Pneumatic & Centre Flow) - This range of magnets is primarily used in pipelines in order to pick up and remove fine ferrous contaminant metal. The Gravity In-Line magnets are used when, as the name suggests, the product falls under gravity. Likewise, pneumatic conveying systems can utilise the Pneumatic In-Line magnets. Both of these feature plate magnets from Bunting which picks up the debris. To capture metal debris from the middle of the pipes product flow, then the Centre Flow In-Line magnets can be used. These are sometimes called Bullet magnets because of their ‘bullet’ or ‘torpedo’ like shape.
Cross Belt Separators – These are implemented when there is a need for continuous metal separation. Sometimes known as either suspended or overband magnets, they are situated above a conveyor belt which is transporting recyclable plastics and the task is to pick up and attract any contaminant metals and separate them from the flow by using a self-cleaning belt.
Eddy Current Separators – These are used frequently in the plastic recycling industry. The eddy current separator creates an eddy current and this current makes non-ferrous metals repel the magnetic rotor which are then collected separately from the recycled plastic.
Bunting also offer a variety of metal detectors. Not only are they perfectly suited for the plastics industry but with the Quicktron models, they can detect metal contaminants and in addition they can actually eject any remaining metal debris, such as stainless steel, that the magnetic separation process has been unable to pick up.