Filling an intended space with self-leveling materials is known as potting. This process is used among others to shield sensitive electronics from damaging outside influences or to provide camouflage or fire protection for components.
The filling or potting process involves filling a pre-specified mold, such as a housing, with a low-viscosity material. The process is applied wherever sensitive electronic components, such as wired circuit boards or power modules, need to be protected from chemical, corrosive or mechanical influences. Potting can even help to reduce thermal loads, dissipate heat and provide camouflage or fire hazard protection. 1K or 2K PU, epoxy or silicone based potting compounds are used which have functions and properties (color, hardness level, material thickness, temperature stability) that can be tailored precisely to the particular application.
Fully potted or encapsulated components are used in standard household appliances as well as in the military and arms manufacturing sectors, in the electronics industry and in the lighting industry. For example, LEDs are frequently potted using PU or silicone based media in order to ensure their long life and excellent lighting quality. Another major area of application for potting is the automotive industry. In this field, components such as control units for engine, transmission, steering and driving assist systems or complete power semiconductor modules for electric motors are potted using suitable casting resins.
A frequently used type of potting process is what is known as "dam and fill", where two potting materials with differing viscosities are used. Typically this process is used to protect fragile structures on circuit boards.
Potting: a reliable material preparation process is key
The important criteria for potting depend on different factors such as the material used, the workpiece design or the curing process selected. Before the actual potting can happen, however, it is always important to employ a material preparation and feed system suited to the task. To achieve high quality, reproducible potting results, it is important to consider parameters such as viscosity, temperature, bubble-free application, filler concentration and the reaction form of the medium. In this case, state-of-the-art systems with heavy-duty feed pumps and sophisticated pressure and vacuum controls provide the necessary reliability.
- The proven LiquiPrep LP804 material preparation and feed system from Scheugenpflug provides guaranteed homogeneous and bubble-free potting materials. Customized mixing and circulation movements prevent sedimentation of the included fillers. The intensity of these movements can be individually tailored to the material.
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- The ideal solution for high material consumption applications is the Scheugenpflug barrel agitator station. Using this system, 200-liter barrels can be fully placed in a vacuum, which also allows for comprehensive preparation of moisture-sensitive media in large barrels.
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Potting: piston dispensing systems provide precise potting capacities
Particularly in the case of potting, the precise and repeatedly accurate measurement of material or individual component quantities is essential. Thanks to their accurately dimensioned dispensing cylinders, which precisely match the desired material capacities or the required mixing ratio, piston dispensing systems offer distinct advantages in this case. Moreover, the dispensing accuracy with these systems does not depend on the pressure, temperature or viscosity of the casting resin used, ensuring additional process reliability.
- Multi-piston dispensers are the ideal choice for potting many small and medium size components quickly and with reproducible quality. The particular advantages of these systems are in vacuum applications, since the fixed evacuation and ventilation times can be allocated to many workpieces. But even in the case of atmospheric potting, multi-piston dispensers provide a high part throughput per time unit. For instance, depending on the application requirements, it is also possible to implement 24-fold or 48-fold potting.
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|TIP: In addition to other factors, the potting result is also primarily determined by the geometry of the part. The more angles in the design, the more programming and parametrization are required in order for the potting material to reach every void. It is therefore recommended that you discuss your component designs early on with a potting expert in order to promptly minimize any problems.|