Plastic injection-molded shells are widely used in industries like electronics, automotive, appliances, and consumer goods due to their versatility, cost-effectiveness, and design flexibility. Below are common materials and their characteristics:
### **1. Common Materials for Injection-Molded Shells**
#### **(1) ABS (Acrylonitrile Butadiene Styrene)**
- **Characteristics**:
- Good impact resistance and toughness
- Excellent surface finish (can be easily painted or electroplated)
- Moderate heat resistance (~80–100°C)
- Good dimensional stability
- **Applications**:
- Electronic housings (e.g., TV casings, computer keyboards)
- Automotive interior parts
- Toys (e.g., LEGO bricks)
#### **(2) Polycarbonate (PC)**
- **Characteristics**:
- High impact resistance (nearly unbreakable)
- Excellent transparency (if clear grades are used)
- High heat resistance (~120–135°C)
- Good electrical insulation
- **Applications**:
- Transparent covers (e.g., LED light diffusers)
- Bullet-proof glass (laminated PC)
- Medical devices and automotive headlights
#### **(3) Polypropylene (PP)**
- **Characteristics**:
- Lightweight and flexible
- Excellent chemical resistance (to acids, bases, and solvents)
- Low cost
- Poor UV resistance (unless stabilized)
- **Applications**:
- Food containers
- Automotive bumpers
- Household appliance parts
#### **(4) Polyethylene (PE)**
- **Types**: HDPE (High-Density PE) & LDPE (Low-Density PE)
- **Characteristics**:
- Good chemical resistance
- Lightweight and durable
- Low friction coefficient
- **Applications**:
- Bottle caps
- Storage bins
- Pipes and fittings
#### **(5) Nylon (PA, Polyamide)**
- **Characteristics**:
- High mechanical strength
- Good wear and abrasion resistance
- Absorbs moisture (can affect dimensions)
- **Applications**:
- Gears and bearings
- Power tool housings
- Automotive under-hood components
#### **(6) POM (Polyoxymethylene, Acetal)**
- **Characteristics**:
- High stiffness and low friction
- Excellent dimensional stability
- Resistant to creep and fatigue
- **Applications**:
- Precision mechanical parts (e.g., gears, zippers)
- Automotive fuel system components
#### **(7) PC/ABS Blend**
- **Characteristics**:
- Combines PC’s toughness and ABS’s processability
- Better heat resistance than ABS alone
- **Applications**:
- Laptop and smartphone cases
- Automotive interior trims
### **2. Key Characteristics of Injection-Molded Shells**
- **High Precision**: Tight tolerances achievable (~0.1–0.5mm)
- **Smooth Surface Finish**: Can be glossy, matte, or textured
- **Lightweight**: Compared to metal alternatives
- **Design Flexibility**: Complex geometries with ribs, bosses, and undercuts
- **Cost-Effective for Mass Production**: Low per-unit cost at high volumes
### **3. Material Selection Considerations**
- **Mechanical Needs** (Strength, Flexibility, Impact Resistance)
- **Thermal Resistance** (Will it be exposed to high temps?)
- **Chemical Exposure** (Will it contact oils, solvents, or UV light?)
- **Aesthetic Requirements** (Color, transparency, surface finish)
- **Regulatory Compliance** (Food-grade, flame retardancy, RoHS)
Would you like recommendations for a specific application?
