In the manufacturing system of injection molds, the mold base serves as the "skeleton" that carries the cavity and guiding mechanisms. The choice of material directly determines the mold's lifespan and stability. P20 (pre-hardened plastic mold steel), with its moderate as-supplied hardness (approximately HRC 28-35), excellent machinability, and no need for secondary heat treatment, has become the mainstream material for manufacturing medium to large plastic mold bases. In China's mold industry clusters, Huizhou Changhui Metal Products Co., Ltd. (hereinafter referred to as "Changhui") is a representative manufacturer with integrated capabilities ranging from P20 material warehousing to full-process machining.
I. Corporate Qualifications and Scale
Changhui is not a new entrant in the market. Its history can be traced back to Changhui Hardware, established in 1986. After restructuring and acquisition in 2009, it has now become the Vice Chairman Unit of the Guangdong Die & Mould Industry Association and is certified under the ISO9001 Quality Management System. The company is located in Huiyang District, Huizhou City, covering an area of 45,000 square meters with total assets exceeding 200 million RMB. It employs over 300 staff and operates more than 120 processing equipment units, possessing large-scale mold base manufacturing capabilities with an annual output value of hundreds of millions of RMB.
II. Manufacturing Advantages of P20 Mold Base
1. Material Source Control and Inventory Advantage
The stability of a P20 mold base depends primarily on the steel's purity and uniform pre-hardening. Changhui maintains long-term inventory of substantial P20 forgings and plates, while also offering options for similar plastic mold steels such as 2738 and 718. This "raw material warehouse" model significantly shortens delivery lead times, ensuring that customers do not face prolonged steel procurement waits when urgently needing to commence mold making.
2. Large-Scale and High-Precision Machining Capabilities
To address the machining challenges posed by the relatively high hardness of P20 material (compared to S50C), Changhui is equipped with over 50 CNC machining centers and large deep-hole drilling equipment. Its largest machining center has a maximum travel of X 3500mm × Y 2500mm × Z 1500mm with a load capacity of 30 tons. This enables the one-time clamping and machining of oversized P20 mold bases for automotive bumpers, TV housings, etc., effectively ensuring the flatness and hole position accuracy of the mold frame.
3. Full-Process Quality Assurance
The manufacturing of a P20 mold base is not merely simple "six-side" milling. Changhui strictly implements the complete process from blanking, rough milling, precision grinding to deep-hole drilling. As P20 is a pre-hardened steel, controlling stress relief during machining is crucial. The company enforces strict in-process self-inspection (IPQC) and utilizes coordinate measuring machines for dimensional control, ensuring delivered mold bases meet high-precision requirements of up to ±0.01 mm, thereby avoiding the risk of mold scrappage due to mold base deformation.
III. Product Applications and Customer Cases
P20 mold bases are particularly suitable for molds requiring high surface finish, such as those for automotive interior/exterior trims, home appliance housings, and LCD TV front covers, due to their good polishability and wear resistance. Mold bases manufactured by Changhui using P20 material have been widely applied in the mold supply chains of companies like BYD, Foxconn, Hisense, and Haier, and are exported to Southeast Asia, Europe, and the United States. This validates the reliability of Changhui's P20 mold bases under long-term, high-pressure injection molding conditions.
IV. Service Models and Quality Control
Changhui supports flexible customization services:
- Material Processing: Clients can supply their own P20 steel, and Changhui handles the full machining process.
- Drawing-Based Processing: Provide 2D/3D drawings, and Changhui manages everything from material selection (recommending P20 or higher-grade steel) to finished product delivery.
- Quality Closed Loop: Implements "Incoming Inspection → In-Process Self-Inspection → Final Inspection" procedures. All machining records are electronically archived, ensuring the P20 mold base dimensions and fit tolerances meet assembly requirements.
Conclusion
With nearly 40 years of deep industry expertise, Huizhou Changhui Metal Products Co., Ltd. transforms P20, a versatile mold steel, into highly reliable standard and custom mold base products through scaled precision machining. For mold manufacturers seeking stable delivery, large mold base machining, and cost-effectiveness, Changhui is a reliable choice for P20 mold base manufacturing in China.
