Here at Hotmelt.com, we're committed to bringing you news and information about all things hot melt, and today we have one for the electronics manufactures out there. Here's the executive summary: Stop potting with epoxy.
In this article we will dive into a cost-effective, faster and more efficient process called low pressure molding. If you have questions right off of the bat, feel free to contact one of our hot melt experts to get started today!
Potting vs Low Pressure Molding
Potting
Potting was used for many years by manufacturers, and is considered the traditional method of protecting electrical components. Liquid resin is poured over the component and then it is cured until it forms a hard protective barrier. The downsides to this method are longer production times due to the curing process, and the risk of the resin shrinking over time means it could also damage components.
Low Pressure Molding
Low pressure molding came about as a solution for delicate electrical components, such as PCB's, sensors and some cable assemblies. It uses a low amount of pressure to inject plastic into a mold. It offers increased protection compared with potting and has a cleaner and faster production time.
Low pressure molding is an injection process where the PCB assembly or electronic part is placed in a specially manufactured aluminum mold tool, and completely surrounded with a liquid compound that effectively forms the housing for the device.
Low pressure molding is a 3 step process rather than an 8 step process for potting. This removal of process steps reduces manufacturing time, labor and material costs and improves throughput, resulting in increased ROI. There is zero waste, scrap is often recyclable and the process is environmentally friendly, giving off no toxic fumes. The end result is a tamper-proof and environmentally sealed product.
This is Why You Should Stop Potting with Epoxy
Frankly, it is an inferior process.
Low pressure molding offers all the benefits of epoxy potting - it is kind to your connectors and your wires stay safe in their cavities - but avoids the downfalls: Hot melt injection molding gives off no toxic fumes, cycle times are as low as 15 seconds, and the curing process is completely eliminated. Where you once had to wait 24 hours for epoxy to cure, you now have to wait less than two minutes for the hot melt to set. No more aggravating delays, no more lost productivity.
It's not just curing that you eliminate from the process. With potting, you have to mold the case, palletize, settle and go through all kinds of steps just to get your components safe, stable and protected. With low pressure molding, you just insert the electronics, over-mold and test.
Low pressure molding, is much more cost effective as well. The process uses less material than potting, making it cost-effective over the long run, and you won't lose any more money on waste, because there isn't any. You also get to be a sustainability hero - because the hot melt is sourced from natural ingredients, all of your scrap material is recyclable.
Using Polyamide Hot Melts for Low Pressure Molding
What is Polyamide Hot Melt?
Hot melt polyamide adhesives are 100% non-volatile, thermoplastic adhesives resins. Supplied in pellet form and solid at room temperature, they offer beneficial characteristic properties necessary in demanding performance environments. These include:
- Good chemical and grease resistance compared to other chemistries
- Excellent plasticizer resistance
- Good to excellent performance at elevated temperatures
- Low application viscosity
- Adhesion to a variety of substrates
One reason polyamide low pressure molding materials are so innovative is simply the improved process. Instead of traditional potting - which takes eight or more distinct steps and up to 24 hours to complete - low pressure molding equipment combines low pressure and temperature to encapsulate electronics parts in as little as 30 seconds.
The simplified process starts when hot melt polyamides are poured into the melt tank attached to the low pressure molding equipment. The pellets are heated to 180-210C and injected into a predesigned mold set, where the electronics are placed prior to molding. Low pressure and heat are applied, and in as little as 30 seconds, the electronics are fully encapsulated and can be immediately handled and tested.
Low pressure molding is a faster and more efficient process than potting. The polyamide hot melt material can be "skylined" around the electronics, reducing cycle times and raw materials. It also eliminates the housing otherwise needed to contain the potting material. Polyamide simply becomes the housing. Low injection pressure easily molds around fragile components, and low temperature minimize heat exposure to sensitive electronics.