Servizio Comunitario di Informazione in materia di Ricerca e Sviluppo - CORDIS

The development of lubricated liquid crystalline polymers for heavy duty high precision bearing systems

The goal of this research project is to develop integrated liquid crystalline polymer (LCP) sliding systems with both specially formulated lubricants and optimized LCP microstructure and filler contents (such as polytetrafluorethylene (PTFE), molybdenum disulphide, graphite, talcuum, glass fibres, lubricants, etc) for the application in precision machines under high loads which are expected to have the same or better qualities than currently used ball bearings or sinter bearings.

3 base oils in 3 different viscosity ranges were chosen and equipped with wetting modifying additives. Out of these base oils PTFE thickened greases in varying consistencies were made. 53 LCP compounds were developed with different molecular weight and fillers and investigated on their microstructure, their mechanical and tribological properties and their compatibility and wetting behaviour with the lubricants. 2 moulds were designed with different runner systems and gate systems to prevent problems with jetting and welding lines. The best results were achieved with a high viscous polymer and a special nap gate. The injection process was optimized by low injection moulding speed and by injecting against a wall in the mould. As a design for the precision bearings 2 bearing types were chosen for the practical tests: a cylindrical bearing with a diameter of 5 mm and a triangular bearing which may carry both radial loads as well as axial loads.

The results demonstrated that LCP bearings, when enhanced with the appropriate lubricants, display a far better performance than ball bearings, particularly when operating under load and in temperatures up to 150 C. This project has resulted in a product with commercial potential.

Two types of LCP compounds are ready to be introduced as commercial products into the European market, including a special oil and a special PTFE grease as lubricants for different application concerns. Furthermore help in terms of design and construction of technical plastic parts, as well as plastic optimized new bearing design, can be given to the European industry, which may lead to completely new solutions in the field of precision machinery.

Reported by

Dr Tillwich GmbH
Murber Steige 26
72160 Horb-Ahldorf
Germany
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