Basic material PEEK and its technology

The top quality technical plastics play an increasingly important role in today’s plastic moulding. Among these materials, Polyether Ether Keton (PEEK) has a special place and is becoming frequently used to substitute metallic components for plastic. The reason is simple: this special material is heat- and deformation resistant up to a temperature of appr. 300oC, and the components made of it are extremely resistant to all kinds of chemical substances. They are highly wear resistant and accurate to dimension. All these characteristics enable this material to spread dynamically, above all in the automotive industry.

Processing through injection moulding:

Being a special material, it is processed with an equally special technology. The basic material needs to be dried at 160-180 degrees C. in a dry-air dryer for 5-6 hours. Since PEEK basic materials are usually sold with glass-fibre or carbon filament reinforcement, their processing occurs at a temperature between 390-420oC. Injection moulding machines must be equipped with a highly wear-resistant bimetallic cylinder and a nitrided pulley as well as with high-performance ceramic heating elements. Injection mould temperature is 180-220oC which in particular cases involves an oil temperature of 240-250oC during malleablizing (due to a high degree of heat loss). In order to make malleablizing effective, suitable heat insulation must be provided for. Due to high temperature, the tool parts are subject to enormous stress, which is especially true for the die inserts. Therefore, mould materials are not everyday objects and special knowledge is required to ensure the tightness of malleablizing holes. Due to this high temperature and a thermal expansion caused by considerable thermal stress, the moving parts of tools can only be lubricated using special lubricants and require more attention than is usual.

The pump vane shown here is manufactured in compliance with strict requirements for PEEK with a four-bucket, currently a cold-runner mould. As the opposite sides of this component need to be parallel, moulded parts have to undergo further processing. This finishing is madeon a special milling machine designed and produced byPlastic Art. Here the parts assume their final form. This machine ensures that the strict dimensional tolerance according to specification as well as the required surface quality are attained.