Metal MIM Surface Treatments

Summary of Metal MIM Parts  Production Process and Application

The MIM manufacturing process generally includes: mixing and granulation, injection molding, degreasing, sintering, and secondary processing.
(1) Main technical features of Metal MIM parts:

• 1. It is suitable for the forming of various powder materials, and the product is widely used;
• 2. High utilization rate of raw materials and high degree of production automation, suitable for continuous mass production.
• 3. It can directly form small parts with complex geometric shapes (0.03g ~ 200g);
• 4. The dimensional accuracy of the parts is high (±0.1%～±0.5%), and the surface finish is good (roughness 1～5μm);
• 5. The product has high relative density (95-100%), uniform organization and excellent performance;

Several commonly used surface treatment processes for Metal MIM Parts

Polished
Using mechanical, chemical or electrochemical action, the surface roughness of the workpiece is reduced to obtain a bright and flat surface.

Electroplating
The process of attaching a metal film to the surface of a metal or other material by electrolysis. Electroplating can prevent metal oxidation (such as rust), improve wear resistance, electrical conductivity, reflectivity, corrosion resistance (copper sulfate, etc.) and enhance aesthetics.

PVD treatment
The use of physical processes to achieve mass transfer, the process of transferring atoms or molecules from the source to the surface of the substrate. Its function is to spray some particles with special properties high strength, wear resistance, heat dissipation, corrosion resistance, etc.) on the matrix with lower performance, so that the matrix has better performance.

Blackening
It is a common chemical treatment method to produce an oxide film on the metal surface to isolate the air and achieve the purpose of rust prevention. When the appearance requirements are not high, blackening treatment can be used. The main components of the blackening liquid are sodium hydroxide and sodium nitrite.

Phosphating

It is a process of chemical and electrochemical reaction to form a phosphate film. The main purpose of phosphating is to:

1) Provide protection to the base metal and prevent the metal from being corroded to a certain extent;
2) It is used as a primer before painting to improve the adhesion and anti-corrosion ability of the paint film.
Spray treatment.

It is a coating method that is dispersed into uniform and fine droplets by means of pressure or centrifugal force through a spray gun or disc atomizer, and is applied to the surface of the object to be coat.