Introduction to metal injection molding methods,

Introduction to metal injection molding methods,

Metal injection molding (MIM) is a new powder metallurgy near-net forming technology extended from the plastic injection molding industry. It is well known that plastic injection molding technology can produce various products with complex shapes at a lower price, but the strength of plastic products is not high. In order to improve its performance, metal or ceramic crushing can be added to the plastic to obtain products with high strength and good wear resistance. In recent years, this idea has developed to collectivize the content of solid particles, and completely remove the adhesive and densify the green body in the subsequent sintering process. This new method of comminution metallurgy molding is called metal injection molding. Metal injection molding is a new technology of comminution metallurgy near-net molding that extends from the plastic injection molding industry. There are many methods of metal injection molding, which are introduced by Zhongwei Precision.

1. In powder metallurgy, the basic process steps of metal injection molding are as follows: first, select the required alloy powder and binder, then blend the powder and binder into a uniform feed at a certain temperature, and then conduct injection molding after granulation, and after degreasing, the formed green body is sintered and densified into products.

2. Metal powder injection molding powder and powder manufacturing technology have high requirements for MIM material powder. Its selection should be conducive to fusion, injection molding, degreasing and sintering, which is often contradictory. Its research includes: crushing shape, particle size, particle size composition, specific surface area, etc. The data lists the properties of suitable material fragments. Due to its fine requirements, the price is generally high, and some even reach 10 times of the price of traditional powder metallurgical crushing, which is the key factor limiting the wide application of MIM technology. The production methods mainly include carbonyl method, high-pressure water atomization method, high-pressure gas atomization method, etc.

3. Adhesives. Adhesives are the core of metal injection molding technology. In MIM, adhesives have two basic functions, namely, improving the fluidity to fit for injection molding and maintaining the shape of the blank. In addition, it should be easy to remove, pollution-free, and reasonable in cost. Therefore, various adhesives have emerged. In recent years, according to the requirements of degreasing method and adhesive function, the adhesive system has been gradually developed from experience selection to targeted design. The adhesive is generally composed of low molecular component and high molecular component plus some necessary additives. The low molecular component has low viscosity, good fluidity and easy removal. The polymer component has high viscosity and strength, and maintains the strength of the molding body, A proper proportion of the two can obtain more crushing loading capacity and obtain products with good accuracy and uniformity.

4. Fusion, which is the process of mixing metal powder and adhesive to obtain uniform feeding. Because the nature of the feeding determines the performance of the injection molding product, the mixing process is very important, which involves many factors, such as the way and sequence of adding adhesive and powder, the fusion temperature, the characteristics of the mixing device, etc. This process step has always remained at the level of empirical exploration. An important indicator for evaluating the fusion process is the uniformity and consistency of the feed obtained.

The above is the introduction of metal injection molding method. I hope it will help you.