Best helps you answer basic questions about the MIM process
time：2020-05-08Views：310 Author：Best Seiko
In recent years, MIM is no longer a mysterious process due to the extensive use of MIM technology in mobile phone parts such as Cato and buttons. Product engineers in many other industries have also begun to learn about the unique process of MIM. According to the previous indo-mimd information, I have reorganized some common problems of MIM for everyone. Of course, these problems are designed for students who first understand the process of MIM. Teachers just ignore it. 1. What is MIM technology? The full name of MIM is metal injection molding, which means metal injection molding. A manufacturing technology that combines plastic injection molding with traditional powder metallurgy. 2. How does MIM work? Fine metal powder is made of a thermoplastic material and a binder to form a raw material substance. This raw material substance is actually a plastic particle containing metal powder and an adhesive. Then through the injection molding method that everyone is very familiar with, to form the blank of the required product. Then it is processed to remove the binder component (called degreasing), and then the degreased product is placed in a controlled high-temperature environment and heated and sintered to obtain a dense metal part. 3. Was the metal melted during the molding process? No, only the binder melted so that the powder could flow like a plastic material. Cooling adhesive is another component with a certain strength. The other parts are then degreased and sintered to remove the binder and achieve a high density and strength to meet the requirements of their mechanical properties. 4. What is the difference between MIM and conventional PM processes? Traditional PM uses one-way high pressure to press rough metal powder into a fixed position to manufacture moderately complex equipment. In particular, the density was not improved further during the sintering process. The density value produced by this method is between 80-90%, which limits its physical properties as an alloy. Due to the flexibility of MIM, the manufacture of complex products is not limited. The combination of fine metal powder and high-temperature sintering enables MIM products to achieve very high densities. This makes MIM products and precision materials have similar characteristics. 5. Will the other parts shrink during the removal of the adhesive? No, the volume of the other parts will not change during the degreasing process. However, up to 20% of the deformation will occur in the other part during sintering. 6. What is the density and strength of the MIM part? The density of a typical MIM is theoretically higher than 96%. The specific density characteristics depend on the choice of alloy, but in any case it is close to precision materials. 7. Why use MIM? MIM has advantages in manufacturing fine, high-complexity parts. Such parts are difficult or costly to produce using traditional machining or casting techniques. For details, please refer to the article: Guidelines for choosing MIM process. 8. Which materials can be used for production? Almost all metal alloys can be used in the MIM process. Among the types of materials commonly used in MIM, typical alloys include high-strength steel, nickel-added stainless steel, and superalloys. Other material processing includes refractory alloys, titanium and copper alloys, low-melting alloys including brass, bronze, zinc aluminum, but it is not economical to use in the MIM process. 9 What is a good way to realize the benefits of MIM? In the early design stage of the product production cycle, the application of MIM technology is a good way to achieve the benefits of MIM. 10. Lead time? The typical lead time for processing and submitting samples is 8-10 weeks. However, according to specific engineering requirements, the corresponding delivery cycle can be shortened. 11. What is the average annual output? In general, the average annual output of a typical product should exceed 20K. 12. Is there a criterion for the definition of complexity? There is no right or wrong here. According to the rule of thumb, if a drawing has a size over 20, it is suitable to be a good MIM part. 13. Is there a limit? Like any other technology, MIM technology also has limitations. The product's large weight is limited to 240 grams (from an economic point of view, the weight is generally limited to no more than 50 grams). Certain geometric characteristics can also be problematic (extra-thick or ultra-thin sections). The progress of the process in recent years has made the great weight of mim products continue to break through. 14. What kind of tolerances will be achieved? The typical MIM tolerance is 0.3% to 0.5%. However, the tolerance depends largely on the geometric characteristics of the product. Exceeding the technical tolerance of MIM can be achieved by machining. 15. What equipment is used in the process? The following equipment is mainly used in the MIM process: MIM mixing & granulating equipment, MIM injection molding equipment, MIM degreasing equipment, MIM sintering equipment, MIM post-processing equipment. 16. Can MIM be thermally treated or electroplated? Yes, MIM parts can be heat treated, electroplated, machined, forged, PVD vacuum plated, etc., like traditional machined products.