1. Low-Pressure Injection Molding Overview
Low-pressure injection molding (LPIM) is a method of molding in which the material is injected into the mold in a low-pressure environment, unlike conventional injection molding. This process is used frequently for encapsulation of electronic components, and fragile elements, and for sealing air and gas.
2. How the Low-Pressure Molding Process Works
Low-pressure molding process Under the low-pressure molding process, thermoplastic materials such as polyamide (PA) are heated up and the molten materials are injected into a cavity. The high-low injection pressure minimizes the stress on the parts, making it one of the best results for delicate parts.
Steps in the Low-Pressure Molding Process:
- Material loading: Thermoplastics are melted in the machine.
- Mold Preparation: Clean and prepare molds, typically with release agents.
- Injection: The molten material is forced into a chamber under controlled pressure.
- Cooling: The component hardens as it cools in the mold.
- Ejection: Ejection is the phase where the molded product is removed.
3. Benefits of Low-Pressure Molding
Gentle Pressures Save Sensitive Parts: Protect the Components
- Reduced Cycle Times: Lower pressure requirement allows for faster cooling.
- Easier to Design Mold: Reduced pressures lead to less rigid molds.
- Sustainable: No more need for secondary encapsulation [Waste reduction]
4. Disadvantages of Low-Pressure Molding
Low-pressure molding has advantages, but there are disadvantages:
- Material Restrictions: Not all thermoplastics are suitable, an example being only polyamide.
- Power Facility Cost – Specialized low-pressure materials can drive up costs.
- Low Details Precision: High geometries might not be possible.
5. Use Cases Across Industries
Cold-Element Molding & A variety of Low-Pressure Injection Molding Applications
- Electronics: Sensors, connectors, and circuitry encapsulation.
- Automotive: Covering wiring and delicate electronic components.
- Medical Devices: Sealed, biocompatible parts.
- Consumer Goods: Long-lasting, waterproof components of the appliances.
6. Low-Pressure Molding vs. Traditional Injection Molding
| Feature | Low-Pressure Molding | Traditional Injection Molding |
| Injection Pressure | Lower | Higher |
| Material Compatibility | Limited | Broad |
| Applications | Delicate/Encapsulation | Mass Production |
| Tooling Cost | Lower | Higher |
| Cycle Times | Faster | Slower |
7. Low-Pressure Molding — Things to Think About When Starting Projects
Keep these points in mind when designing a low-pressure molding project:
- Material Selection: Select thermoplastics that are compatible with the application.
- Part Design Because simple parts can lead to simple molds, they also can lead to lower costs.
- Don’t Go Too Complicated – Higher precision is not achieved due to less precision.
- Suitable Production Volume: Medium to low production runs.
8. Common Defects and Improvement Strategies in Low-Pressure Molding
Some defects in low-pressure molding and ways to address them include:
| Defect | Cause | Improvement Strategy |
| Warping | Uneven cooling | Ensure uniform mold temperatures |
| Incomplete Fill | Low injection pressure | Increase injection speed/pressure |
| Flash | Poor mold clamping | Improve mold fit and clamping force |
| Air Bubbles | Trapped air in material | Degas material before injection |
9. About BFY Mold
BFY Mold is a trusted provider of injection molding and mold manufacturing solutions, offering services like mass production, on-demand production, CNC machining, and mirror spark. With our factory and years of expertise, we deliver precision-engineered parts tailored to your needs.
