Low Pressure Molding
Adhesives
Hot melt resins for overmoulding electronics components
Our low-pressure molding adhesives, based on polyamide hot melt technology, further simplifies protecting electronic components. They offer:
- Easy processability at low pressure alongside compatibility with fragile components for streamlined operations and design flexibility
- Vibration and chemical resistance, including thermal cycling, fluids, high humidity and UV exposure for improved electrical insulation and performance overall
- Hot melt material with no mixing required, up to 90% bio-based formulation as well as allowing recyclability of injected material for reduced waste and environmental impact
Featured product: TH 8672B
Frequently Asked Questions about Low Pressure Molding Adhesives
What is Low Pressure Molding?
Used to encapsulate electronic components, Low Pressure Molding (LPM) technology protects and seals items against moisture, dust, dirt, and debris. Simplified to a single and fast process, LPM is a cross between classic plastic injection and resin potting. This system operates at low pressure (typically between 1.5 to 40 bar) and low temperature (180-220°C), making it significantly gentler than traditional injection molding methods. This protects the product and allows a lower equipment cost while ensuring complete encapsulation of sensitive components. The technology, developed in Europe during the 1970s, has evolved to become ideal for protecting connectors, onboard electronics, LEDs, and PCBs (Printed Circuit Boards). It is most often used with hot melt polyamide materials, which offer excellent adhesion properties and environmental resistance. The process creates a custom-fitted, solidified protective layer that not only shields components from environmental factors but also provides mechanical support and electrical insulation, achieving protection ratings like IP67 for a complete water and dust resistance.
What are typical and key applications for Low Pressure Molding?
Typical applications are captors and sensors encapsulation (including temperature, pressure, position and motion sensors), PCB overmolding for advanced circuit protection, connectors and cables requiring waterproof sealing and good flexibility or and antennas for wireless communication devices. LPM is used in various key markets, such as automotive (for engine control units, cabling, and lighting systems), medical (for patient monitoring devices and diagnostic equipments), electronics (for consumer devices and industrial control), smartphones (for internal component protection), and other industrial areas where environmental protection and precise electronic component sealing are crucial. The versatility of LPM technology makes it particularly valuable in applications requiring IP67 or higher protection ratings and those exposed to harsh operating conditions.
What are the benefits of Low Pressure Molding in terms of process?
LPM process is an alternative to classic high-pressure injection molding and resin potting. Low Pressure Molding provides a small process footprint with lower energy consumption due to low injection pressure and the need for less equipment. It also offers high production speed with reduced cycled times and one-component product; immediate set with no mixing errors. Finally, it provides easier manufacturing with a simplified process.This process also allows for more precise component positioning and reduced internal stresses on delicate parts, resulting in fewer defects and improved quality control. Additionally, the lower operating temperatures (180-220°C) compared to traditional injection molding help prevent thermal damage to sensitive electronic components while maintaining excellent adhesion properties.
What are the benefits of Low-Pressure Molding in terms of sustainability?
Low-pressure molding significantly reduces waste by avoiding excess material compared to traditional injection methods. Bostik also offers natural, solvent-free, and up to 90 biobased materials, which help decrease reliance on fossil fuel-based resources. The process itself is more energy-efficient due to lower operating temperatures and pressures, reducing overall carbon footprint. Additionally, this thermoplastic material can be melted and even recycled for better end-of-life management. The closed-loop capability means that runners and excess material can be reprocessed, further minimizing waste and supporting circular economy initiatives. When combined with efficient production planning and optimized mold design, LPM technology enables manufacturers to meet increasingly stringent sustainability targets while maintaining high-quality component protection.
What is the difference between low pressure molding and high pressure molding?
| Feature | Low-Pressure Molding | High-Pressure Molding |
|---|---|---|
| Pressure Applied | Uses low pressure (around 100 PSI) | Uses high pressure (up to 25,000 PSI) |
| Material Flow | Gentle injection, ideal for delicate components | Fast injection, suitable for mass production |
| Temperature Range | Lower temperatures (180-220°C) | Higher temperatures (185-300+°C) |
| Best for | PCBs, sensors, switches, batteries | Plastic parts, medical devices, automotive dashboards |
| Durability | Less durable, but better precision | More durable, but can cause molding defects |
| Cycle Time | Slower cycle time | Faster cycle time |
What materials are used in low pressure molding?
| Material Type | Examples | Key Features |
|---|---|---|
| Thermoplastics | Polyamide (PA), Thermoplastic Elastomers (TPE), Thermoplastic Polyurethane (TPU) | High flexibility, impact resistance, and chemical durability |
| Thermosetting Materials | Reactive Polyamide (PAR), Urethane-Acrylate | Strong adhesion, heat resistance, and long-term durability |
| Hot-Melt Adhesives | Polyolefin-based compounds | Low viscosity, excellent sealing properties, and environmental protection |
What is an LPM machine in manufacturing?
An LPM machine can refer to different types of industrial equipment:
- Low Pressure Molding (LPM) Machine: Used for encapsulating electronic components, sealing connectors, and protecting circuit boards. These machines operate at low pressure to prevent damage to delicate components while ensuring strong adhesion and environmental protection.
Key Features of LPM Machines
- Low Injection Pressure: Prevents damage to fragile electronic components.
- Fast Processing Time: Enables efficient production cycles.
- Eco-Friendly Materials: Uses polyamide-based molding compounds.
- Enhanced Protection: Shields against moisture, vibration, and contaminants.
Common Applications
- PCB Encapsulation: Protects circuit boards from environmental hazards.
- Automotive Electronics: Ensures durability in harsh conditions.
- Medical Devices: Provides insulation for sensitive equipment.
- Consumer Electronics: Used in smartphones, wearables, and connectors.
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