At the request of an electric motor manufacturer, Syneo was called in to improve the process of dosing thermal paste for heat dissipation on windscreen wiper motors.
Thermal paste has a texture identical to modelling clay, making it difficult to dose and deposit in small quantities - in this case less than 1 gram - with precision and repeatability. The customer was dispensing thermal paste using a piston pump system, which required the material to be heated to between 50°C and 70°C to fluidize. The high piston pressure resulted in leaks and a loss of 10 to 20 % of product in the drums. The system was also difficult to maintain in good working order.
The customer was looking for more reliable equipment, capable of handling a high dispensing rate while guaranteeing repeatable dosing. After a feasibility test, Syneo proposed a dispensing system with a Viscotec MT-XS drum vacuum and a volumetric dosing pump. The dosing pump uses a valve-less worm gear system, enabling instantaneous product dosing without heating, so that the process can be started immediately without any further prior adjustment. The system operates on demand. What's more, at the end of dosing, the product is drawn off in the opposite direction to that in which it was deposited, bringing dosing to a clean, burr-free halt.
The Viscotec drum vacuum is also equipped with a worm pump that pushes the product into the hose at a pressure of less than 25 bar, compared with 100 to 120 bar with conventional systems. Thanks to this technology, the pressure in the pipes transferring the product to the pump is reduced, eliminating potential leaks. As the system does not depend on product viscosity, it is no longer necessary to pre-heat the product. This simplifies the process, and as the thermal paste does not change its appearance, it does not dry out. Nor are there any intermediate adjustments to be made according to climatic conditions. Drum bottoms are fully utilized, with no loss of product.
This solution offers a dispensing performance of 0.3 ml in 3.5 seconds with good repeatability and high precision, with an ideal CPK > 1.67.
The customer's problem is solved and he is satisfied: " When I started up the system on my two lines, there were no problems whatsoever, either at start-up or with the quantity. We switched on the system, performed a small purge and the first two doses were impeccable. Integration is perfect, given that our product is very difficult to dispense. And above all, we've done away with the heating pipes. "The new system therefore fully meets the customer's initial requirements, since it eliminates product heating and curative maintenance - only preventive maintenance is now required.
Learn more: www.syneo.net