Highly filled silicone for sealing headlights
Endurance testing proves resistance to wear of ViscoTec stators
Modern LEDs are high-performance products which, as a consequence of the energy density of the light, ask a great deal of the materials used. Organic plastics quickly reach breaking point in this field and material manufacturers are focussing their attention on new types of plastic. The aim is to combine as many different properties as possible in a single medium. In the case of LED production, for example, light stability, temperature resistance, UV stability, resistance to ageing and high adhesion are of crucial importance.
Manufacturers tend to use what is known as “additivation” – adding fillers with specific characteristics – to achieve this versatility of material properties. In the medium itself, these fillers often increase density and result in high material aggressiveness towards the dosing components. The eccentric worm pump by ViscoTec has already proved its compatibility for use with abrasive media in numerous applications and is now doing it again: endurance testing carried out in our in-house laboratory tested the resistance to wear of the stator first in 180,000 cycles of quantity dosing and then in continuous operation. The test medium – an RTV silicone filled with aluminium oxide – was taken from a drum and fed into the 4RD6-H EC dispenser from the ViscoTec RD series. In keeping with the requirement from the automotive industry, a dot-dosing application with 0.027 ml per dose was simulated for sealing headlights. Three times a day, temperature and pressure values were recorded at the pump outlet and doses were evaluated. The parameters recorded were highly consistent and there was no indication of wear.
Computer tomography was applied in quality assurance to measure and evaluate the stator geometry before and after endurance testing. There was no visual or dimensional evidence to suggest defects. The ViscoTec dispenser was thus deemed suitable for this application.
Fluids enhanced with additives have been in use in dosing applications in automated settings for many years, and the trend is on the increase. The abrasiveness of the media used, which is often a consequence of additivation, is forcing the manufacturers of dosing technology and equipment to confront the subject of wear and the factors that influence it. ViscoTec is determined to face up to this challenge, turning its many years of experience to its advantage in doing so. The long product life of ViscoTec stators is the result of continuous optimisation of the elastomer compounds. For customers this means fewer failures, minimum maintenance overheads and more effective automated production lines.
About ViscoTec Pumpen- u. Dosiertechnik GmbH
ViscoTec Pumpen- u. Dosiertechnik GmbH primarily deals with systems required for conveying, dosing, applying, filling and emptying medium to high-viscosity fluids. The technological leader headquarter is in Töging a. Inn (Bavaria). Furthermore ViscoTec has subsidiaries in the USA, in China and in Singapore and employs almost 120 people worldwide. Numerous sales partners all over the world complete the international distribution network. Next to technically sophisticated solutions to even the most complicated application, ViscoTec is the single point of contact to deliver all components for a complete system: from emptying to preparing and to dosing. This guarantees successful interaction of all components. All fluids showing a viscosity of up to 7.000.000 mPas can be conveyed and dosed almost pulsation-free and with extremely low shear. ViscoTec offers comprehensive consulting for every application and, if required, extensive tests will be carried out in close cooperation with the customer. The dosing pumps and systems are perfectly adapted to their respective application whether it is the food sector, the automotive industry, the aerospace field, the medical technology, the pharmaceutical industry and many other branches.