Product Info

Selecting the right engineering plastic for precision components is crucial to achieving high dimensional accuracy and durability. This article compares the properties of LCP, PPS, and PEI, and explains how to choose the best material for your application.

In precision component design common in electronics, automotive, medical, and industrial equipment the choice of engineering plastics ("enpla") directly impacts product quality. Key requirements include dimensional stability, low water absorption, heat resistance, and machining precision.

1. Requirements for Engineering Plastics in Precision Parts
To ensure performance and reliability, enpla used in precision components must offer:
- Dimensional stability: Minimal deformation during molding and usage
- Low water absorption: Prevents swelling or property changes due to humidity
- Heat resistance: Maintains strength and form under elevated temperatures
- Machining precision: Supports fine-tolerance injection molding or CNC processing
With these criteria in mind, we will compare three leading engineering plastics: LCP (Liquid Crystal Polymer), PPS (Polyphenylene Sulfide), and PEI (Polyetherimide).

2. LCP (Liquid Crystal Polymer) - Features and Applications
- Extremely low coefficient of thermal expansion (similar to metals)
- High flowability for ultra-thin, micro-precision molding
- Excellent mechanical strength and dimensional consistency
- Compatible with fillers like glass fiber
Common Applications: Electronic connectors, sensor housings, and micro medical parts.
LCP excels in humid and high-temperature environments, with minimal dimensional variance and longer mold life.

3. PPS (Polyphenylene Sulfide) - Features and Applications
- Heat resistance over 200°C (180°C for continuous use)
- Extremely low water absorption, maintaining shape and properties
- High stiffness and inherent flame retardancy (self-extinguishing)
- Good machinability for complex designs
Common Applications: Automotive ECUs, precision gears, pump parts.
PPS is ideal for high-temperature and tight-tolerance settings and offers easy post-molding processing due to low shrinkage.

4. PEI (Polyetherimide) - Features and Applications
- High heat resistance (170 - 180°C continuous use)
- Excellent electrical insulation and creep resistance
- Flame retardant without additives (UL94 V-0)
- Balanced rigidity and toughness with excellent transparency
Common Applications: Aircraft components, medical devices, IC trays, and optical-grade precision parts.
PEI's clarity and performance make it suitable for applications demanding both appearance and structural reliability.

5. Key Considerations for Material Selection
Before choosing an engineering plastic for precision components, evaluate:
- Required operating temperature and long-term heat exposure
- Product shape, thickness, and tolerance demands
- Sensitivity to moisture and environmental conditions
- Need for electrical insulation and flame resistance
- Mold design complexity and production cost balance
Selecting materials based solely on datasheets can lead to failure. Instead, factor in real-world usage environments and processing methods.

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