Sensitive electronic components surround us in everyday life — from the sensors in our cars to the medical devices monitoring patient health, from LED lighting systems to the batteries powering mobile phones. As these components become smaller, more intricate, and more critical, manufacturers face a growing challenge: how to protect them from harsh environments without causing damage during the protection process itself.
This is where low pressure molding for sensitive electronics comes in as a purpose-built solution.
Not all electronics are created equal. When engineers talk about sensitive electronics, they are referring to components that can be easily damaged by mechanical stress, heat, or pressure. These include:
Traditional high-pressure injection molding, which operates at pressures of 500 to 2,000 bar, can sheer off components, crack solder joints, or deform wire bonds in seconds. Potting compounds require long cure times and add significant weight. Conformal coatings provide limited mechanical protection. None of these methods are ideal for the most delicate assemblies.
Low pressure molding (LPM) is a process that uses thermoplastic hot-melt adhesives — primarily polyamide and polyolefin compounds — to gently encapsulate electronic components. The material is heated to a molten state and injected into a mold cavity at pressures of only 1.5 to 40 bar, then cools and solidifies around the component within seconds.
The process is remarkably simple, consisting of just three steps:
This simplicity stands in stark contrast to potting, which can involve up to eight separate steps and cure times of 24 to 72 hours.
The most obvious advantage is right in the name. With injection pressures of only 1.5 to 40 bar — compared to 500 to 2,000 bar in conventional injection molding — LPM will not damage fragile components. Solder joints remain intact, fine wire bonds stay connected, and MEMS sensors continue to function after encapsulation. This makes it possible to overmold assemblies that simply cannot survive traditional injection molding.
Low pressure molding provides a thick, durable barrier that protects against:
This level of protection is critical for electronics deployed outdoors, in vehicles, in medical environments, or in industrial settings where conditions are unpredictable.
Speed matters in manufacturing. Where potting requires mixing two-part compounds, vacuum settling, and hours of oven curing, LPM achieves complete encapsulation in 30 to 60 seconds. The material requires no mixing and no curing — it simply cools and solidifies.
This translates directly to higher throughput, lower work-in-process inventory, and shorter lead times. For manufacturers producing in volume, the difference between a 30-second cycle and a 24-hour cure is substantial.
Low pressure molding for electronics gives engineers significant design freedom:
By consolidating multiple parts into a single molded unit, manufacturers can reduce bill of materials (BOM) complexity, simplify inventory management, and lower assembly costs.
LPM molds are typically made from aluminum rather than hardened steel, which is required for high-pressure injection molding. Aluminum tooling is less expensive, faster to produce, and easier to modify — making LPM well-suited for prototyping and low-to-medium volume production runs.
Combined with fewer process steps, reduced material waste, lower labor costs, and smaller equipment footprint, the total cost of ownership for LPM can be significantly lower than potting or traditional injection molding.
The thermoplastic materials used in LPM are derived largely from renewable vegetable-based raw materials. They are solvent-free, produce no VOC emissions, and are RoHS and REACH compliant. Unlike potting compounds, which are thermoset and cannot be reworked, LPM materials are thermoplastic — meaning they can be melted and reshaped if a part needs to be reworked or recycled.
| Feature | Low Pressure Molding | Potting | Conformal Coating |
|---|---|---|---|
| Injection pressure | 1.5–40 bar | Atmospheric | N/A (spray/dip) |
| Cycle time | 30–60 seconds | 24–72 hours | 4–12 hours |
| Process steps | 3 | 7–8 | 6–8 |
| Cure required | No | Yes | Yes |
| Waterproof rating | Up to IP69K | Up to IP68 | Limited |
| Mechanical strength | High | Medium | Low |
| Reworkable | Yes | No | Limited |
| Material waste | Low (skylining) | High | Medium |
| Tooling cost | Low (aluminum) | Minimal | None |
Low pressure molding is used across a wide range of industries where electronic protection is critical:
Not all LPM service providers offer the same level of capability. When selecting a partner for low pressure molding, consider:
Farway Electronic, based in LongGang, Shenzhen, offers pcba low pressure injection coating services backed by four low-pressure injection molding machines and a technical team covering electronic engineering, structural engineering, and testing. The company holds ISO 9001, ISO 13485, IATF 16949, and ISO 14001 certifications, reflecting its commitment to quality across medical, automotive, and general electronics manufacturing.
Farway's LPM service covers the full process from technical consulting and engineering through product and mold development to production. Applications include medical and industrial sensors, LED lighting, mobile phone and power batteries, connector harnesses, circuit boards, and microswitches — all components where gentle handling and reliable environmental protection are essential.
Low pressure molding has become the preferred method for protecting sensitive electronic components because it solves the fundamental problem that other methods cannot: it provides robust, complete environmental protection without subjecting delicate assemblies to damaging pressures or temperatures. The combination of gentle encapsulation, fast cycle times, design flexibility, and sustainability makes LPM an increasingly compelling choice for manufacturers across medical, automotive, consumer, and industrial sectors. As electronics continue to shrink in size and grow in complexity, the need for protection methods that can keep pace will only increase — and low pressure molding is well-positioned to meet that demand.
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