FAQ

Some common problems in electronic waterproof protection technology are listed below for reference. Due to the influence of various factors such as the requirements of product structure and use environment in the actual application process, the problems encountered and corresponding solutions are also different. For any technical support, please contact us.

What the Benefits of Low Pressure Molding?

LPM can over-mold extensively products and enhance product performance.LPM technology benefits mainly reveal in two aspects below:

Product Performance

Environmentally friendly (RoHS).
Water-proof.
Electrical insulation.
Mechanical protection from impact.
Resistance to temperature (UL94 V-0).
Resistance to Chemical.

Production

Simplify the process, enhance productivity.
Shorten the development cycle, reduce the R&D cost.
Save production space.
No hazardous materials during production.
Thermoplastic no cure time and increased reliability.
Molds design flexibility.

What is the Application of Low Pressure Molding?

Low pressure molding technology can be applied to wide range of industries and any unique product that needs to be sealed and protected against the environment such as PCB, automotive electronics, automotive wire, connector, sensor, micro switch etc.

More Application details： http://www.wlhs.com.cn/q_case/img.php?lang=en&class1=329

What is different between Low pressure molding and Traditional molding?

LPMS selects high performance hot-melt adhesive, which has excellent mobility. The adhesive takes very small pressure to make it flow to mold, therefore, the products successfully over-molded without causing any harm in the process, greatly reducing the defect product.

	PA Hot melt LPM	Traditional molding
Material	PA Hot melt resin	ABS、PBT、PP
Injection pressure	1.5~40 bar	350~1,300 bar
Injection temperature	190~230℃	230~300℃
Clamping force	1 Ton	Over 50 Tons
Mould material	Steel and aluminum	Only steel
Damage to the mold	No damage	Wear and tear
Injection machine	Air cylinder driven	Hydraulic driven

What is different between Low Pressure Molding and Epoxy Potting?

	PA Hot melt LPM	Epoxy molding
Case	Need	Meed case
Working temperature	-70~150℃	180℃
Housing	No need housing	Need housing
Cycle time	2-60 seconds	Chemical reaction needs 24 hours
density	0.98	Above 1.2
Curing	Much less curing time	Need curing
Working space	Occupy less space	Occupy large space
Energy consumption	Low	High
Resin consumption	Less	Much more
Process	Simple	Complex
Vacuum pumping	No need	Need

How much is the shrinkage rate of material after low pressure injection molding?

Low pressure molding material’s shrinkage rate is slightly lower than traditional molding material. Low pressure molding contraction ranges between 1%~1.5％. It depends on materials.

How to avoid air bubbles in the product?

Mold structure design, such as increasing the exhaust inserts, the way of injection.
Mold DFM.
For larger injection volume products, we might design multiple injection to avoid it.
Using transparent resin to test and adjust molding parameters through mold trial and small production of the samples.

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