How to choose PEEK mold steel?

PEEK (polyether ether ketone), as a high-performance engineering plastic, has a wide range of applications in high-end fields such as aerospace, medical devices, electrical and electronics, due to its excellent mechanical properties, high-temperature resistance, chemical resistance and biocompatibility. However, the high injection temperature of PEEK material has special requirements for the selection of mold steel. Choosing the right mold steel not only ensures the service life of the mold, but also improves the quality and productivity of the products. According to the amount of products and precision requirements, select the mold steel suitable for PEEK injection molding processing, the amount of less or lower precision requirements, you can choose a more cost-effective mold steel.

First, the characteristics of PEEK material requirements for mold steel

1. High temperature stability

The melting point of PEEK is about 343°C, and the injection molding processing temperature is usually between 360°C and 400°C. The temperature of the mold steel must be good. Therefore, the mold steel must have good high-temperature strength and thermal stability, able to work at high temperatures for a long time without softening, deformation or performance degradation, to avoid the injection molded products lack of glue, poor dimensions, unstable performance.

2. Abrasion resistance

PEEK melt has a high viscosity, injection requires high pressure. At the same time, PEEK is often added glass fiber (usually add 10%GF to 40% glass fiber, even 50% GF), carbon fiber and other reinforcing materials, the surface of the mold to produce greater wear. Therefore, the mold steel should have high hardness and excellent wear resistance to extend the service life of the mold.

3. Corrosion resistance

At high temperatures, PEEK may release certain corrosive gases that can cause corrosion damage to the mold. Especially in the processing of PEEK materials containing additives, the corrosion problem is more prominent. Therefore, the mold steel needs to have good corrosion resistance.

4. Good polishing properties

For PEEK products requiring high surface quality, the mold steel needs to have good polishing performance to ensure that the surface finish of the product to meet the requirements. However, PEEK injection molded products, most of the internal structure, the appearance of the finish requirements are not high.

Second, suitable for PEEK processing mold steel type

1. H13 (4Cr5MoSiV1) hot work mold steel

• specificities: H13 is a commonly used hot work mold steel with excellent high temperature strength and toughness, good heat resistance and good resistance to thermal fatigue.
• suitability: Suitable for the manufacture of mold parts subject to high temperature and pressure, such as cavities, cores, etc., can meet the requirements of PEEK injection molding processing on the mold steel.

2. S136 (American grade 2083, German grade 1.2083) high grade corrosion resistant mold steel

• specificities: S136 is a pre-hardened corrosion-resistant mirror plastic mold steel with good corrosion resistance and polishing properties, and hardness up to 48-52 HRC.
• suitability: Suitable for PEEK molds with high requirements for surface finish and corrosion resistance, such as medical devices and precision electronic components.

3. M310 (German grade 1.2344) high performance hot work die steel

• specificities: M310 steel combines the high-temperature properties of H13 and the corrosion resistance of S136 with good thermal stability, wear resistance and polishability.
• suitability: Suitable for manufacturing high-precision and demanding PEEK molds, it is an excellent choice for comprehensive performance.

4. Other high performance mold steels

Such as: UDDEHOLM steel Mirrax 40, ThyssenKrupp's V320 and other special mold steel, designed for difficult plastic injection molding processing, with high hardness, high toughness and corrosion resistance.

Third, the key considerations for the selection of mold steel

1. Process temperature

• heat resistance: Mold steel needs to be able to withstand the high processing temperatures of PEEK injection molding for long periods of time without softening or deforming.
• heat conduction: Good thermal conductivity helps cooling of molds, increasing productivity and improving product quality.

2. Material hardness

• abrasion resistance: High hardness improves abrasion resistance and reduces wear and tear on molds due to fiber reinforced materials.
• Toughness Balance: While increasing the hardness, it is necessary to ensure that the mold steel has sufficient toughness to avoid cracking or shattering under high pressure.

3. Corrosion resistance

• chemical stability: Selecting steel with corrosion resistance extends mold life and reduces maintenance costs.

4. Surface treatment

• nitriding: Improves surface hardness and wear resistance for mold parts that require high wear resistance.
• Chrome plated, titanium plated: Increase the corrosion resistance and finish of the mold surface and improve the mold release performance.

5. Machinability

• workability: Reduce manufacturing difficulties and costs by selecting steels that are easy to machine and polish.
• Heat Treatment Stability: Steel should be dimensionally stable during heat treatment to reduce the risk of distortion.

IV. Based on cost and customer requirements

1. Integrated assessment of cost and performance

• Cost considerations: High-performance mold steel is more expensive, but has excellent performance for high value-added PEEK products.
• production volume: For high volume production, choosing a high quality mold steel can reduce the total cost of ownership; for low volume production, cost and performance can be balanced according to requirements.

2. Communication with suppliers

• Technical Support: Work with die steel suppliers and professional heat treatment manufacturers for professional material selection advice and heat treatment process support.
• Material Validation: Test specimens, if necessary, to verify that the properties of the steel meet the requirements.

3. Focus on mold maintenance

• regular inspection: Molds that work at high temperatures and pressures require regular inspection and maintenance to detect and solve wear and corrosion problems in a timely manner.
• rational use: Operate by professional personnel and follow the correct operating procedures to avoid damage to the mold due to misuse.

In short, the choice of PEEK mold steel directly affects the performance and service life of the mold, as well as the quality of products and production efficiency. Comprehensive consideration of PEEK injection molding of high temperature, high pressure, corrosion resistance and other processing characteristics, should give priority to the selection of high-temperature strength, abrasion resistance, corrosion resistance and good polishing properties of the mold steel, such as H13, S136, M310 and so on. At the same time, reasonable heat treatment and surface treatment process, as well as standardized mold use and maintenance, is also the key to ensure the performance of the mold. Techeng Technology is a professional PEEK mold processor, providing PEEK open mold injection molding services, from copying, machining sampling, 3D printing sampling, to mold design and manufacturing injection molding processing one-stop service, welcome to consult.