Laser Filter Cleaning in the Plastics Industry

Laser filter discs form part of filtration systems used in the manufacturing of plastic products and plastics recycling. They are designed to remove impurities and contaminants from the molten plastic material as it flows continuously through the filter disc. They also eliminate any harmful particulates generated during the process, such as dirt, dust, and smoke.

Laser filters are used to remove particulate like metal, wood, glass, and sand from recycled plastic material, it also filters out other plastic types of a higher density to purify the final product.

The recycled plastic material is heated and extruded before passing through the laser filter disc, which removes any contaminants and impurities. The cleaned material is then pelletised and ready to be used at the manufacturing stage for all types of uses, sometimes the very thing it was recycled from and thats how you reach a circular economy in plastics.

Why do laser filters need cleaning?

They are used in a high-temperature environment where they are continuously exposed to molten plastic material. Over time, the filters can become clogged with contaminants, such as wood, steel, aluminium and sand. If left uncleaned, these contaminants can cause the filters to “blind” reducing their effectiveness, resulting in reduced filtration capacity, increased pressure and potential equipment damage.

Cleaning them is essential to maintain their performance and prolong their lifespan. Regular cleaning removes any accumulated contaminants and prevents them from building up and interfering with the filtration process. A properly cleaned filter ensures the production process runs smoothly, minimises downtime, and ensures the final product meets the desired quality standards.

Aswell as the production benefits the commercial savings are not to be underestimated as 1 laser screen can cost in excess of €2,000.00 and so simply replacing them everytime can be extremely costly. A properly maintained and professionally cleaned laser screen can last 3-4 times longer than conventional cleaning.

How do you clean laser filters?

The traditional method of cleaning laser filter discs typically involves a quick jet wash after burn off. However, the ultra-fine mesh of the laser filters requires a more complex, multi-process cleaning approach. 

Even after burn-off and jet washing, the fine mesh still contains trapped and burnt carbonized plastic, metals and sand which even a pressure washer cannot remove

To achieve near 98%+ cleanliness, ultrasonic cleaning is mandatory. 

To ensure the optimal performance of laser screens, it is essential to implement a cleaning regime that removes the contaminants and prevents their reaccumulation. 

• Pyrolysis (burn off): A cleaning process that utilises high temperatures in a controlled setting to reduce the plastic to a fine ash. Leaving behind only inorganic material such as glass, sand and all metal types. Remember the plastic is not the problem, its everything thats left behind, so whilst the burn off is essential it doesnt get you any closer to a clean product.  
• Jet washing: The jet washing process is important for removing all the loose particulate and ash from the surface, if you have a lot of aluminium trapped in your screen a high pressure wash can reduce this by sheer force. Its more of a hammer than a sclapal but effective in its own right
• Ultrasonic cleaning: Utilising high-frequency sound waves, ultrasonic cleaning with a carefully chosen cleaning chemical, is a technique that effectively agitates and eliminates contaminants from the filter. This method is especially efficient in removing residual trapped inorganic particles that the jet wash simply could not remove. The sound waves generated by this process create high-energy cavitation bubbles that collapse and implode on a microscopic level, providing a blasting force in the extremely small filtration holes.

Take a look at some of the results we can achieve:

The benefits of cleaning laser filters

Cleaning laser filters is critical for sustaining performance, efficiency and quality within plastic recycling industry. 

By cleaning the contaminants from the laser filters, companies can ensure that the production process runs seamlessly and that the final product meets the necessary quality standards. Moreover, this practice helps prevent equipment breakdowns, minimises downtime, and saves businesses from costly replacement parts.

Although the multi stage process of cleaning filter discs takes longer and than the traditional method of just pyrolysis and jet wash the benefits make the extra effort  worthwhile. For instance, laser filter screen lifetimes can be extended up to double or triple compared to burning alone. 

Throughput can be increased by up to 20% due to reduced blinding. Longer times between blockages reduce downtime and bursts significantly. While the material type and quality going into the extruder are beyond your control, maintaining the hot melt filter line is something that can be managed

What sets Sonic Solutions apart from in-house cleaning and other subcontract cleaning operations is our ability to use a variety of cleaning processes to achieve the desired level of cleanliness. Our cleaning expertise, experience, flexibility, and commitment to meeting customers’ needs and demands are the reasons why major and highly demanding plastics manufacturers, such as Jayplas and BPI Berry rely on us to remove unwanted contaminants from their laser filters.