How to choose the right material for industrial shredder blades

A shredder blade is a type of knife that is installed on industrial shredders or granulators, which are machines used to shred waste materials such as rubber, tires, wood, paper, polymers, plastics, textiles, etc. Industrial waste shredders are known to play a vital role in the recycling industry. shredder blades in turn have a huge impact on the efficiency of the shredder. There are many variables that affect shredder blade efficiency, such as cutting angle, the number of tools, cutting speed, chip load, etc. One of the most important factors is the suitability of the tool material for handling industrial scrap. This article will talk about how to choose the right shredder blade based on the material being slit.

Here is the list of contents

1. For shredding wood

2. For shredding plastics

3. For shredding tire rubber

For shredding wood

Common waste woods include cardboard, paper, solid wood, and plywood. SK5 is a practical and economical choice for fragile wood, such as branches, twigs, and cardboard. It is a carbon tool steel with good wear resistance but poor plasticity and hardenability. SK5 is commonly used to make woodworking knives and sample-sized molds. Its performance is not particularly good and it is less expensive than other types of woodworking steel.

For shredding plastics

In the plastics industry, recyclers got a late start in the business compared to the scrap wood sector. Waste plastics can often be a huge mixture of additives and fillers. They contain not only low-grade plastics but also high-value plastics. Therefore, we need to identify the types of plastics in the input mixture.

Cutting of plastics such as ABS, PE, PPboard

Generally, for these plastics, we choose alloy carbon steels such as 65Mn spring steel, T10, D2 for these plastics. This is because these carbon steels have very good hardenability and high impact load resistance to tempering. These blade materials are generally used in cutting blades with lower cutting speeds and larger bends. Cutting blades made from low alloy steels work well in these situations and are praised for their properties when the blades must withstand traction forces in excess of 270 MPa while requiring hardness to be maintained at HRC 52-55.

For crushing plastic chips and pellets

The pelletizer consists of a fixed cutter and a hobbing cutter. The pelletizer rolls and cuts the hob knife at the outlet and sieves the plastic mixture together into pellets. The hob cutter is the main working part of the entire pelletizer system. The heat treatment hardness of the hob knife is required to be around HRC 58-62. In addition, the shredding knives need to be more resistant to wear, heat and impact. Therefore, we prefer hardened carbon steel 9CrSi, spring steel 65Mn, or even HSS W18Cr4V.

For shredding tire rubber

With the rise of precious metal prices and the recycling of all kinds of rubber scrap, what we usually call black trash is gradually becoming black gold. Contractors and dealers can easily purchase worn tires from automobiles at very reasonable prices and process them into quality recycled rubber. Recycled tire rubber is not only inexpensive, but it is a versatile and environmentally friendly material that has a wide range of uses in many places.

Tungsten carbide has excellent wear resistance and high-temperature resistance for processing hard steel such as copper and high carbon steel and has excellent applications in cutting rubber tires. At room temperature, it has a hardness of around 69-81 HRC and still maintains a hardness of 60 HRC at 1000°C. Tungsten carbide is relatively more expensive compared to materials with lower properties. As a result, shredder manufacturers now usually weld, braze or screw carbide tips to the hob body rather than making the entire blade from tungsten carbide. When it comes to reducing costs, people are now shredding with knives that have larger concave surfaces, high output quality, and are indexable when worn.