Size Reduction​

Size reduction is a crucial step when processing plastic ready for reuse. Plastics are reduced in size, usually between 6 – 10mm, and then cleaned, dried and separated into reusable plastic granules.

Why Size Reduce?

Reducing the size of the plastic material is a vital part of recycling plastics for three main reasons:

1. Reducing the particle size of the processed material increased the surface area present. This results in a reduced energy requirement during washing and drying, thereby reducing operational costs.

2. Sink Float tanks are typically used to separate plastics according to their density. Uniform particle sizes ensure the reliability and efficiency of this separation process

3. In standard situations plastic resin is sold according to its weight and purity. Reducing the particle size of the final product increases the density of resin contained within any given space. In turn, this process lowers the associated costs involved in transportation and storage.

Particle size is an important factor to take into consideration when producing plastic pellets for resale into the plastic recycling market, for a number of reasons. 

Perhaps the most significant reason is that the quality and purity of a plastic pallet is generally determined by its size and consistency, and producing plastic pellets with a too-large particle size could lead to their rejection from plastic recycling and remanufacturing companies. It is therefore important to ensure that a quality commodity is being achieved through the optimised use of plastic recycling machinery such as Granulators for ensuring an even particle size, as well as Plastic Washing Machines, Separators and Dryers for ensuring the purity of the plastic pellets. 

Another reason why particle size is important is for the processing of the materials. Before plastic in-feed material is processed through the washing, drying, and separation stages of production, it is generally passed through a plastic shredder to make a material size that is easier to process. This allows the material to be managed more efficiently by the later stages of the process, with less energy usage, and therefore reduced operational costs. On top of this, the smaller, more uniform particle size allows for a more accurate separation by the Separation Machinery; thereby ensuring the quality of the end product. 

Rotajet manufactures a range of Shredders and Granulators that can produce a consistently small particle size that will not only optimise the efficiency of your production, but will ensure a pure, quality plastic pellet ready for remanufacturing.

How to Protect Shredder and Granulator Blades

Shredder and granulator blades are designed to endure high levels of impact and high volumes of materials in a recycling line, but over time can become worn as a result of the continuous impact and eventually need replacing. It is therefore important to ensure that they are maintained properly to reduce the risk of machine downtime and enhance the production quality. To prolong the lifespan of shredder and granulator blades, there are a number of measures which can be taken.

  • Shredder and granulator blades are usually mounted upon bearings which allow them to rotate. These bearings should be regularly checked and lubricated to ensure their smooth rotation so that the blessed can perform to the highest possible standard. On top of this, blades should also be oiled and at least once a month to keep them running smoothly. 
  • It’s important not to overload the production line with infeed materials as this can lead to their accelerated wear. The excessive loading of materials can cause a high-level of intense impact upon the blades that they are not designed to manage. Therefore, the regulated feed of material, for example through and Feed Hopper, is necessary to ensure that blades are not overwhelmed with materials. 
  • These blades are designed specifically to suit the type of infeed material being processed. Therefore, the excessive processing of damaging contaminants such as metals and glass in a plastic recycling line can lead to the blades becoming blunted and consequently producing a lower-quality end-product. 
  • If possible, the blade can be safely removed from the shredder or granulator and sharpened before being replaced into the machine. This method helps to reduce the costs of replacement, but can only be done if blades do not show signs of lasting damage. Furthermore, the method of sharpening blades can only be repeated so many times until they must be replaced. 
  • Over time, blades can become contaminated and blocked by infeed materials, which in turn can impact upon their productivity. To combat this, blades should be cleaned once a month to remove contaminants and residues that could be impacting upon their performance.

The actions listed above are necessary steps to ensuring the longevity of shredder and granulator blades. As a part of Rotajet’s customer aftercare initiative, we offer a number of spare parts that can keep your machine running at high-quality whilst minimising the risk of production downtime. 

On top of this, with a number of Servicing Contracts available, Rotajet can undertake maintenance checks on your machine to produce actionable reports on how to improve production. At Rotajet, we understand the importance of producing a high quality end product for recycling, and that’s why we build machines that are built for purpose, and solutions designed to last. For more information on how to protect shredder and granulator blades with our range of spares and maintenance and servicing contracts, get in touch with our team today.


Contact Rotajet

We aim to get back to any enquiry within 12 hours, so please contact us if you are interested in a specific machine or would like to discuss an individual cleaning application. Our friendly team are happy to help via email at or by phone on +44 (0) 1924 271446.