Dispensing of liquid, thermally conductive material

Thermally-conductive gap fillers or thermal interface materials are used in many areas of electronics, such as sensing systems, controller units and transmission modules or battery systems. They act as a thermal bridge between a hot component (such as a circuit board) and a heat spreader (e.g. housing) to dissipate heat away from the component and prevent its failure from overheating. The advantage of using gap fillers is that they provide a soft, form-in-place elastomer that fills all the unique and intricate air voids and gaps. This is invaluable particularly in the production of fragile assemblies, where alternatives that are not component shape-specific (e.g. gap-filling elastomeric pads) can cause damage by over-stressing solder joints and leads.

The process of thermal gap filler application involves a highly abrasive, two-part material, which is metered and homogenously mixed, before it is dispensed in usually very small shots. The material then cures in place, either in room or elevated temperature. The application requires a special dispensing system robust enough to withstand the flow of abrasive particles and precise enough to operate with very small components.

Designed specifically to withstand highly abrasive material, the system PAR 2EH is our solution to gap filling and potting processes, where thermal interface materials are applied to transfer heat away from components. The system can be interfaced with automated systems for fully or semiautomatic applications.



Complex, yet strikingly effective applications

No matter which industry we look at – be it electronics, automotive or aviation – we will notice that bonding has replaced the established joining methods such as welding or screwing. For example, up to 18 kilograms of adhesive are used in the production of a single car. The electronics industry relies on adhesives for potting or sealing of components. In any case, bonding is a complex technique and requires significant specialist knowledge. Material manufacturers are constantly working on new adhesives and increasingly often they are also tailoring them to specific applications. In many cases, bonding is the only viable technique of binding modern materials.


Adhesive material can be based on epoxy resins, silicones, polyurethanes or methacrylates and it can be a one or a multi-part substance. Multi-component adhesives are metered and mixed by dispensing systems according to a fixed mixing ratio. Polyurethane adhesives often perform a sealing function, are easy to process and have a very good chemical resistance. Most commonly used are epoxy adhesives. They can be processed very well at room temperature and are highly resistant.


Methacrylate adhesives usually have a very short pot life, which can complicate their processing. On the other hand, they offer the advantage of short curing times and particularly high strength. They are an excellent alternative for the joining of metal, glass and duromeric plastics.


Adhesives do not adhere easily to all components. Depending on the component properties, a pre-treatment such as by corona flame, corona primer or brushing, may be required. The subsequent application of the adhesive can be carried out in various ways, for example in a dot or bead form. After the components are joined, curing systems such as infrared light, ultraviolet light or continuous furnace can be used to accelerate the bonding reaction and speed up the time in which the components are available for the next production step.

In summary, the bonding and sealing process is a relatively complex one with many factors at play. The selected material must be a perfect fit for the application, the application parameters must be clearly and precisely defined and lastly, a metering solution capable of processing the selected material in the defined way needs to be identified. METER MIX® offers robust and proven metering systems which are continuously adapted to the evolving demands of adhesive technology. They present an accessible solution to process-reliable and high-quality processing of adhesive materials.