How to Polish MIM Stainless Steel Parts?

MIM is the abbreviation of metal injection molding, which is a high-tech technology that combines traditional powder metallurgy technology with plastic injection molding technology.

It first mixes the selected powder with the binder, then granulates the mixture and injects it into the required shape, which can produce a variety of parts with complex geometric shapes in large quantities and quickly.

Common materials for MIM are mainly the following:

Process flow: batching → mixing → granulation → injection molding → chemical extraction → high temperature debonding → sintering → surface treatment → finished product

Application field

Mainly used in aerospace, automotive parts, electronic parts, military industry, daily necessities (watch straps, watch buckles, luggage accessories) mechanical parts, medical equipment, etc.

Why is polishing needed?

Because after the sintering process of metal injection molding products, the surface finish of the finished product will be relatively rough, and there will be slight burrs on the surface. And because metal injection molding is to mix metal powder with its binder and then inject it into the model, there may be fine stainless steel powder particles attached to the surface of the product.

In order to achieve a better surface finish, the surface treatment of some products not only needs to remove the burrs on the surface, but also needs to achieve a mirror effect, such as the metal card tray of a smartphone, the volume button, the bracket on the laptop, etc.

Therefore, for MIM products, surface treatment processes such as grinding and polishing are often added. In particular, the rapid development of consumer electronics in recent years has not only driven the development of the MIM industry, but also played a good role in promoting the development of the surface treatment polishing industry.

Polishing steps

Mechanical polishing

1. The polishing equipment uses an automatic polishing disc machine
2. Polishing consumables matching

Manual polishing

Polishing consumables matching, as shown in the table below

Polishing effect display

Using the above polishing scheme, the cutting force is strong during rough polishing, the line after medium polishing is fine, and the fine polishing can quickly produce light; the polished product can achieve a mirror black light effect, clear and bright.