Original equipment manufacturers (OEMs) always want their assemblies potted for various reasons. But typically, it is done to protect against shock and vibration or to not let moisture or corrosive agents get near the electronics.
Here’s a basic guide to getting it right.
Electrical Potting involves filling a complete electronic assembly using a compound material. While the process does seem simple, just involves pouring liquid resin into an enclosure, it can pose a real challenge for those doing out.
To achieve the perfect pot there are some factors to assess, to ensure that the dispensed potting material is consistent and repeatable.
It is vital to heat up the resin to facilitate the potting process. This lets the potting mixture flow smoothly through the system when production initiates. With a wide range of resins available, it’s crucial to consult the supplier of the resin. So that they can recommend what the optimum flow temperature should be.
Resin To Hardener Ratio
For certain resin and hardener systems, the weight ratio could be disparate, to produce cured material with differences in properties, normally in flexibility or hardness. Here too it’s good to consult with the supplier to ascertain if the mixing ratio is fixed. Or if some modification is possible.
To achieve optimum results for your own application, you should run a few trials before production volumes begin.
In general terms, there are two types of electrical potting methods available.
- A cylinder-piston machine features cylinders, for the resin and hardener that are sized, with the purpose that the volume ratio is that of the potting compound. During the insertion of pistons into the cylinders, the accurate proportion is passed through the mixing area.
- An alternative method to this employs a gear pump and enables more control over the ratios. This method uses screws that are turned by individual motors controlled by electronics. While the screws turn at an optimal speed, they distribute the resin and hardener in the correct ratio. Although this method offers more control, the machines in themselves are basically more expensive to buy.
Mix of Material
After the ratios have been controlled the resin and hardener need to be mixed together. This operation is commonly achieved by deploying a detachable mixing nozzle. It’s vital that the nozzles are detachable as once the mixing process is completed, they have a short life span. The curing process signifies they require replacing regularly.
Mixing nozzles assure optimum performance by segregating and intermixing the materials into a homogeneous stream. It’s a standard that the longer the nozzle the better mix of material.
It is vital for the materials to be mixed at pressure so they can be blended effectively. If the pressure is too little, then this can cause an uneven mix. If you are unsure of the correct pressure you require. Or have faced problems with your current settings. It’s best to contact the supplier of the materials for advice. These are some of the vital factors to be conscious of in order to consistently achieve the perfect pot.