Injection Mold Material Selection: Key Factors and Best Choices

1. Common Injection Mold Materials

A. Tool Steels (Most Widely Used)

Tool steels offer excellent hardness, wear resistance, and thermal stability. Common grades include:

1. P20 Steel (1.2311 / DIN Standard)

• Hardness: 28-32 HRC (pre-hardened)

• Best for: Medium-volume production (50,000–100,000 cycles)

• Applications: Consumer electronics, automotive interiors

• Pros: Good machinability, cost-effective

• Cons: Lower wear resistance than hardened steels

2. H13 Steel (1.2344 / Hot-Work Tool Steel)

• Hardness: 48-52 HRC (after heat treatment)

• Best for: High-volume production (500,000+ cycles)

• Applications: Automotive parts, medical devices

• Pros: Excellent thermal fatigue resistance

• Cons: Higher cost, requires heat treatment

3. S7 Steel (Shock-Resistant Steel)

• Hardness: 54-56 HRC

• Best for: Molds requiring impact resistance

• Applications: Industrial components, thick-walled parts

• Pros: High toughness, good wear resistance

• Cons: Less corrosion-resistant than stainless steels

B. Stainless Steels (For Corrosion Resistance)

Used when mold longevity and surface finish are critical (e.g., medical or food-grade applications).

1. 420 Stainless Steel (1.2083)

• Hardness: 48-52 HRC

• Best for: Transparent or glossy plastic parts

• Applications: Lenses, cosmetic packaging

• Pros: High polishability, corrosion-resistant

• Cons: More expensive than P20

2. 17-4 PH (Precipitation-Hardening Stainless Steel)

• Hardness: 40-45 HRC

• Best for: High-wear, corrosive environments

• Applications: Medical implants, chemical containers

• Pros: Good strength without heat treatment

• Cons: Lower hardness than tool steels

C. Aluminum (For Prototyping & Low-Volume Production)

• Grades: 7075-T6, 6061-T6

• Hardness: ~15-20 HRC

• Best for: <10,000 cycles, rapid tooling

• Applications: Prototypes, short-run production

• Pros: Fast machining, lightweight

• Cons: Low wear resistance, shorter lifespan

D. Beryllium Copper (For High Thermal Conductivity)

• Hardness: 35-42 HRC

• Best for: Molds requiring fast cooling (thin-walled parts)

• Applications: Small precision components, connectors

• Pros: Excellent heat dissipation

• Cons: Expensive, toxic when machined (requires safety measures)

2. Key Factors in Mold Material Selection

3. Advanced Mold Materials (Special Applications)

• Hardened Steels (e.g., D2, M2): Extreme wear resistance for abrasive plastics.

• Ceramic Inserts: For ultra-high-temperature plastics (e.g., PEEK).

• 3D-Printed Molds (Tool Steel Infiltration): For complex conformal cooling channels.

4. Conclusion: How to Choose the Right Mold Material?

1. Low-volume (<10k parts)? → Aluminum (fast & cheap)

2. Medium-volume (50k–100k)? → P20 Steel (balanced cost & durability)

3. High-volume (500k+)? → H13 or Stainless Steel (long lifespan)

4. Corrosion resistance needed? → 420 or 17-4 PH Stainless Steel

5. Fast cooling required? → Beryllium Copper inserts

Selecting the right mold material ensures higher efficiency, lower costs, and better part quality. Need help deciding? Consult with a mold engineering expert!