Plastic Injection Molding, Die Casting Industry

Is there any metal injection molding?

Posted by author-avatar
0
injection molding supplier

In traditional injection molding processes, pure metals cannot be directly used for injection molding because their melting points are extremely high (for example, iron melts at approximately 1538°C and aluminum at around 660°C), which far exceed the processing capacity of injection molding machines (the maximum temperature of conventional injection molding machines usually does not exceed 400°C). 

However, there are two types of technologies related to "metal + injection molding", namely Metal Injection Molding (MIM) and the combination process of plastic injection molding and metal, which can realize the production of "injection molding-like" metal parts or composite structures of metal and plastic.

Metal Injection Molding (MIM)

This is the only process that can achieve the “metal injection molding” effect. In essence, it involves mixing metal powder with a binder, then using a process similar to plastic injection molding to shape the mixture, and finally obtaining fully metal components.

Core Principles:

  • Mixing: Extremely fine metal powders (such as stainless steel, titanium alloy, copper powder, with a particle size of 5-20μm) are mixed with thermoplastic binders (such as paraffin, polymers) in proportion to make a fluid “metal feedstock” (similar to plastic particles).
  • Injection Molding: A special injection molding machine is used to inject the metal feedstock into the mold. After cooling, a “green part” is obtained (the blank contains a large amount of binder and has low strength).
  • Debinding: The binder in the green part is removed by heating or solvent soaking to form a porous “debound part”.
  • Sintering: The debound part is sintered in a high-temperature furnace (for stainless steel, about 1300°C). The metal particles diffuse and fuse to form a dense all-metal component (the density can reach more than 95%, and the performance is close to that of forged metal).

Advantages and Applications:

  • It can produce complex shapes (such as parts with small holes, grooves, and threads) with high precision (tolerance ±0.1%~±0.5%), and is suitable for small precision metal parts (usually weighing 0.1-50g).
  • Wide range of materials: stainless steel, titanium alloy, tungsten alloy, cemented carbide, etc., to meet different strength and corrosion resistance requirements.
  • Typical applications: medical devices (such as surgical instrument parts), electronic equipment (such as connector pins), automotive precision components (such as sensor housings), watch movement parts, etc.
Newer
Design Limitations and Handling Solutions for Non-Overall Powder Coating of Powder-Coated Parts
Back to list
Older Surface Treatment and Finishing of Plastics and Metals

Leave a Reply

Your email address will not be published. Required fields are marked *