Best Plastics for Injection Molding: From ABS To PEEK

1. ABS (Acrylonitrile Butadiene Styrene)

Best for: Consumer products, automotive interiors, LEGO bricks
Melting Point: ~200°C (392°F)

 Key Properties:

• Good impact resistance & toughness

• Easy to machine and paint

• Low cost & widely available

Limitations:

• Poor UV & weather resistance (may degrade outdoors)

• Not suitable for high-temperature applications

2. Polypropylene (PP)

Best for: Food packaging, medical devices, living hinges
Melting Point: ~160°C (320°F)
Key Properties:

• Excellent chemical resistance (great for labware)

• Lightweight & flexible (used in bottle caps, containers)

• FDA-approved for food contact

Limitations:

• Low stiffness compared to engineering plastics

• Prone to warping if not cooled properly

3. Polycarbonate (PC)

Best for: Bulletproof glass (laminates), electronics, medical devices
Melting Point: ~265°C (509°F)
Key Properties:

• Extremely strong & impact-resistant

• High optical clarity (used in lenses, LED covers)

• Good heat resistance

Limitations:

• Susceptible to scratches (often requires coatings)

• Can yellow under UV exposure

4. PEEK (Polyether Ether Ketone)

Best for: Aerospace, medical implants, oil & gas components
Melting Point: ~343°C (649°F)
Key Properties:

• Exceptional heat & chemical resistance

• Biocompatible (used in spinal implants)

• Retains strength at high temperatures

Limitations:

• Extremely expensive (~10x the cost of ABS)

• Requires high-temperature molding machines

How to Choose the Right Plastic?

Consider these factors when selecting a material:

1. Temperature Resistance – Will the part face high heat?

2. Mechanical Stress – Does it need flexibility or rigidity?

3. Chemical Exposure – Will it contact oils, solvents, or acids?

4. Regulatory Requirements – FDA, ISO, or UL certifications needed?

5. Cost – Is it a high-volume or low-budget project?

Final Thoughts

From everyday ABS to high-performance PEEK, each plastic resin serves a unique purpose in injection molding. For best results:

• Prototype first (test different materials)

• Consult a material supplier (they often provide free samples)

• Optimize mold design (gate location, cooling channels)