Process and application of metal injection molding technology

Process and application of metal injection molding technology

Metal injection molding is a metal processing process, in which fine powder metal is mixed with the measured amount of adhesive material, including "raw materials" can be processed by a method called injection molding, through plastic processing equipment. The molding process allows to be molded in a single operation in high-capacity complex parts. Terminal products are usually component items used in various industrial applications. The nature of the flow rate of MIM raw materials is defined by a physics called rheology. The current equipment functions need to be processed and remain limited to the products that can be molded using 100g or less than the typical roll of the mold per "shot". Rheology does allow this kind of "beat" to be allocated to multiple holes, thus becoming cost-effective. Otherwise, it will be quite expensive to produce complex and large quantities of products made of spare or classic small methods. All kinds of MIM raw materials in the energy are called powder metallurgy, and these contain the same alloy composition found in the industry standards of common and foreign metal applications. The subsequent adjustment operation is carried out in the molded shape, where the adhesive material is removed and the metal particles are combined into the state required for the metal alloy.

Metal injection molding process:

MIM gained attention throughout the 1990s as an improvement in the subsequent conditioning process led to the end product, which was similar to or better than the competition process. The cost efficiency improved by mass production of MIM technology, the "near net type", denied that the expensive and additional operations had not been implemented in the competition process, and met with strict dimensional and metallurgical specifications.

The steps of the production method of metal injection molding electronic parts include combining the metal powder with the adhesive of wax and plastic to produce the combination of "raw materials" that are injected into the hollow mold of the injection molding machine in liquid form. The "green parts" are cooled and demoulded in the plastic molding machine. Then, a part of the adhesive material is removed by solvent, heat furnace, catalytic method, or a combination of methods. A part of the resulting fragile and porous (2-4% "air") needs to condense metal in a process called sintering furnace in the early working condition called "brown". The temperature at which the MIM parts are sintered is almost high enough to melt the whole metal part directly (up to 1450 ℃) and combine on the surface of the metal particles to produce a final solid density of 96-99%^ The MIM metal of the final product has comparable mechanical and physical properties and the parts are made by traditional metal processing methods, and the MIM material is compatible with the same subsequent metal conditioning treatment, such as electroplating, passivation, annealing, carburizing, nitriding, and precipitation hardening.

Metal injection molding applications:

The window of metal injection molding parts lies in the complexity and small size of parts. MIM materials are comparable to metals formed by competitive methods, and end products are used in a wide range of industrial, commercial, medical, dental, gun, aviation and automotive applications. The dimensional tolerance of ± 0.003 inch per linear inch can be shared, and the tolerance is closer to the limit of possible molding and sintering expertise. MIM can produce items that are difficult or even impossible to manufacture effectively by means of manufacturing. The increase in cost is marking, and the MIM operation that usually does not increase the cost is due to the inherent flexibility of injection molding and some complex traditional manufacturing methods, such as internal/external threads, miniaturization, or brand identification.

The design functions that can be implemented to MIM operation include batch code, part number or molding component date stamp; The net content of parts manufacturing reduces the waste and cost of materials; The density is controlled at 95-98%; Integration of parts and complex 3D geometry.

The ability of several businesses to merge into one process ensures that MIM can successfully save delivery time and cost, and manufacturers provide significant benefits. Metal injection molding process is also considered as a green technology. Compared with "traditional" manufacturing methods, such as 5-axis NC machining, it can significantly reduce waste.

There is a wide range of materials available when using the MIM process. The traditional metal processing process often involves a significant amount of material waste, which makes MIM an efficient choice of complex components, including the manufacture of expensive/special alloys (cobalt chromium alloy, 17-4 PH stainless steel, titanium alloy and tungsten carbide). MIM is in extremely thin wall specification (i.e., 0.008 thick), which requires a feasible choice. In addition, the requirement of EMI shielding (electromagnetic interference) has posed a unique challenge, and is currently being successfully achieved through the utilization rate of special alloy (ASTM A753 type 4).