In the field of mold manufacturing, the selection of mold steel is crucial, as it directly impacts the mold's performance, durability, and the final product's quality. Mold steels are broadly categorized into three types based on application scenarios: cold work mold steel, hot work mold steel, and plastic mold steel. Given the specific requirements of medical plastic molds for material purity, corrosion resistance, wear resistance, and polishability, choosing the appropriate steel is particularly important. This article will provide an in-depth analysis of which steel is most suitable for medical plastic molds.

I. Overview of Mold Steels

Mold steels come in a wide variety, including cold punching dies, wire drawing dies, drawing dies, etc. Each type of mold steel must possess corresponding hardness, strength, wear resistance, toughness, and processability according to its specific working conditions. For plastic molds, in particular, outstanding corrosion resistance and polishability are required.

II. Selecting Steel for Medical Plastic Molds

1. S136: Versatile Plastic Mold Steel
   • Application: Widely used in precision plastic products such as cameras, sunglasses, chemical instruments, etc.
   • Characteristics: Combines corrosion resistance, wear resistance, polishability, and dimensional stability, making it ideal for manufacturing high-quality plastic molds.
2. P20: Economical Mold Steel
   • Application: Commonly used in plastic molds and mold bases for household appliances such as TV front covers, telephones, water dispensers, etc.
   • Advantages: Uniform hardness, good processability, excellent polishing and photo-etching performance. Supplied in a pre-hardened state, eliminating the need for heat treatment.
3. S136H: Medical-Grade Plastic Mold Steel
   • Application: Specifically suitable for medical and food industry plastic molds requiring high polish and corrosion resistance.
   • Highlights: Excellent production characteristics, strong corrosion resistance, minimal heat treatment distortion, and low maintenance costs. It is the preferred steel for medical plastic molds.
4. 718: Widely Used Mold Steel
   • Application: Suitable for large plastic products such as TV cases, washing machines, refrigerator inner shells, etc.
   • Features: Easy to process, excellent mechanical properties, processability, and polishing performance. Pre-hardened to improve economic efficiency.
5. NAK80: Special Steel for Mirror Polishing
   • Application: Designed for precision products such as mirror-polished molds, dust-proof light filters, cosmetic boxes, etc.
   • Advantages: Outstanding polishing, cutting, and etching performance, with pure steel quality that requires no heat treatment. Suitable for high-precision mold manufacturing.

III. Conclusion

In summary, considering the specific needs of medical plastic molds, S136H steel, with its excellent corrosion resistance, good polishing performance, and low maintenance costs, is the most ideal choice. It not only meets the high standards of material purity and safety required by medical products but also ensures the mold's long-term stability and service life, making it the top choice for medical plastic mold manufacturing.