Steel Selection and Temperature for Injection Molds of PA66+30% Glass Fiber
PA66 reinforced with 30% glass fiber is a common engineering plastic, known for its high strength and heat resistance. However, it demands high wear resistance and corrosion resistance from mold materials due to the abrasive nature of glass fibers. Considering these factors, the following mold steels are recommended:
High carbon, high chromium tool steel: Such as NAK80 and S136. These steels offer high hardness and wear resistance, effectively resisting abrasion from glass fibers.
Pre-hardened tool steel: Such as H13 and P20. These steels exhibit excellent heat treatment properties, allowing for high hardness and toughness, making them suitable for complex mold geometries.
Nitrided steel: Through nitriding treatment, a layer of extremely hard nitride is formed on the steel surface, significantly improving the mold's wear resistance and corrosion resistance.
When selecting steel, the following factors should be comprehensively considered:
Part complexity: For complex-shaped parts, the mold steel should have good toughness to prevent cracking.
Production volume: For high-volume production, cost-effective steels can be prioritized.
Surface finish requirements: For demanding surface finish requirements, steels with good surface finish can be selected.
Temperature Selection
The melting point of PA66+30% glass fiber is generally around 250°C, and its decomposition temperature is above 300°C. The injection temperature is usually set above the melting point but below the decomposition temperature. The specific temperature setting needs to be adjusted based on the following factors:
Mold material: Different mold materials have different temperature resistance, and the appropriate temperature should be determined based on the steel's properties.
Part wall thickness: For parts with thinner walls, a higher melt temperature is required to ensure flowability.
Cooling method: Different cooling methods have different requirements for injection temperature.
Generally, the injection temperature range for PA66+30% glass fiber is 260-280°C.
The selection of steel and temperature for injection molds of PA66+30% glass fiber is a comprehensive issue that needs to be considered based on the specific product, mold structure, and production conditions.
