In order to protect electronic components from excessive heat and thus damage, more and more thermal conductive pastes are being used in thermal management. Dispensing these reliably and economically requires a great deal of know-how.
Dot dispensing of a gap filler (Figure: ViscoTec Pumpen- u. Dosiertechnik GmbH)
Abrasive thermal pastes are used in many dispensing applications in the electronics industry. By regulating the thermal resistance, these pastes, often called gap fillers (Fig.1 and 2), ensure heat transfer between two components. They place very high demands on the dosing systems: The fillers tend to sediment and they are highly aggressive against the dosing components. Two parameters are therefore decisive. On the one hand, precise maintenance of the pressure level during the dosing process in order to prevent separation between filler and binder. On the other hand, the correct material selection in the design of the dosing components for abrasive materials. The characteristic properties of the dosing material should be able to be used optimally without, however, impairing the reliability, material stability and quality of production. A manufacturing process with suitable application and process technology supports these requirements, protects the material and enables optimum dispensing.
Bead dispensing of a gap filler (Figure: ViscoTec Pumpen- u. Dosiertechnik GmbH)
First of all, a continuous uniform distribution of the solids in the dosing medium must be ensured. The removal and, if necessary, degassing of the product under constant mixing and uninterrupted supply to the dosing process prevents a possible solids concentration as well as sedimentation of the carrier material and fillers. A continuous volume flow without pressure pulsations or backflows can meet these requirements. Low pressures during the dispensing process have also proven to be advantageous. In practice, a large number of projects have shown that reliable dispensing - even of the most abrasive thermal conductive pastes - with the right dosing know-how is no longer a challenge today. Regardless of the degree of automation in production.
„Perfect dispensing of thermal pastes contributes considerably to the longevity and quality of the components and reduces production costs, as these pastes are comparatively expensive.“
