Differences between MIM injection molds and ordinary injection molds

 

Date：[2025/1/10]
 

Metal powder precision injection molding is a molding process that combines traditional powder metallurgy technology with plastic injection molding technology, also known as MIM (Metal Injection Molding) molding technology. Specifically, metal powder and plastic binder are mixed and molded in a mold, and then degreased and sintered to produce metal parts.

Compared with ordinary injection molds, it has some special features in the design of molded parts, pouring systems, cooling systems, and demolding systems.

In terms of molded parts:
1. The shrinkage rate is different because the workpiece not only shrinks during injection molding, but also shrinks after sintering and degreasing.
2. The demolding slope is different, and MIM injection molds have a larger demolding slope, generally taking 1-3 °.
3. The roughness of the mold cavity is different, and MIM injection molds are higher than ordinary injection molds. Usually Ra0.4 is taken.
4. The material requires higher wear resistance because the raw material contains metal powder, which causes greater friction and wear on the mold cavity. MIM injection molded parts must be made of wear-resistant steel and undergo quenching or surface nitriding treatment.

Pouring system design: MIM injection molds should use circular cross-section flow channels as much as possible. Metal powder is a precious metal, and the flow channel should have as little aggregate as possible, so it is necessary to shorten the length of the flow channel as much as possible and reduce bends.

Cooling system: The diameter of the cooling water pipe is 2-4 millimeters larger than that of ordinary injection molds.

Demoulding system: The plasticity and rigidity of the parts are poor, and the layout of the ejection must be sufficient and balanced.
Shenzhen Yujiaxin Tech. Co., Ltd. is a high-tech enterprise dedicated to metal powder injection molding processing. The company is committed to providing high-quality and high-precision metal component solutions through advanced metal powder injection molding technology. With years of technical accumulation and innovative spirit, Yujiaxin has achieved remarkable accomplishments in the field of metal powder injection molding and has won widespread customer trust and praise.