Metal Injection Molding
Application of metal injection molding MIM in the field of electronics
Metal Injection Molding (MIM) is a near-net-shape process suitable for producing small, three-dimensional complex shapes and products with special performance requirements. MIM can use almost most metal materials. Considering the economy, the main application materials include iron-based, nickel-based, low-alloy, copper-based, high-speed steel, stainless steel, gram valve alloy, cemented carbide, and titanium-based metals.
From an economical point of view, MIM products usually weigh about 0.1-200g, and can produce various complex shapes like plastic products, such as external grooves, external threads, tapered outer surfaces, cross through holes, blind holes, concave platforms, Key pins, rib plates, surface knurling, etc.; the product has good surface finish and high dimensional accuracy. Of course, the biggest feature of MIM should be its high production efficiency, which can realize automated, large-scale and large-scale production, and can produce a large number of products in batches in a short period of time.
Figure 1: The basic process flow diagram of metal injection molding MIM
The application of MIM is very extensive, and the MIM products that penetrate into our lives are mainly in the three major fields of electronic products, automobile manufacturing and medical equipment. Today let's take a look at the daily hardware and electronics field
1. Mobile application
Speaking of consumer electronics, mobile phones should be the most familiar products. In addition, smart wearable devices are also a very popular application area. Mobile phone parts are relatively complex in shape, and they also pay great attention to the feel of use. As the function of the fuselage continues to climb, the parts must be more refined, and the performance must also meet the requirements.
Figure 2: Mobile phone camera - a very classic metal injection molding MIM product
Figure 2: Phone Kakato--a very classic metal injection molded MIM product
Electronic communication products are an important market for MIM parts. Almost all mobile phone manufacturers purchase a large number of MIM products, and the miniature and multi-functional components in communication are exactly where the advantages of MIM technology lie. MIM injection molding can achieve the advantages of reduced production costs, increased production efficiency, and smaller and lighter parts. The realization of thin and light components, reduced weight, and improved hand feel are the advantages that mobile phone developers strive for. The development of mobile phone projects is very fast, and only MIM technology can make so many parts in a short period of time.
In addition to Cato, the hinges used in the current popular folding screen phones are also MIM parts. Of course, in addition to the above typical examples, there are many applications of MIM components in consumer electronics.
Figure 3: Folding screen hinges require very high precision for production and are very difficult to produce, probably only MIM can do it
Chart: 4: Metal Injection Molding MIM Communication Parts
2. Watch application
The global watch industry has annual sales of 15 billion US dollars, and metal powder injection molding has been closely involved in the production of many new watches. Powder injection moulded bracelets, clasps and watch holders are produced worldwide.
At first, due to the saturation of this field and the reduction of manufacturing costs of traditional forging processes, the rapid growth rate of metal powder injection molded parts was once slowed down in the traditional watch industry. However, with the popularity of smart wear and the complexity of watch structure, the application of powder injection molding in watch parts has grown rapidly.
Figure 2 is a head tablet used on a smart wearable.
The reason why the metal powder injection molding technology can be successfully applied in the watch industry is that the process is suitable for mass production. The MIM process generally has a production cycle of 5-7 days, and can be continuously supplied after one cycle. The daily output varies from Hundreds to hundreds of thousands per day can be satisfied. At the same time, since MIM products are formed by a mold similar to an injection mold, a very high degree of freedom in geometric design can be obtained. As long as the products that can be formed by an injection mold can be basically produced using the MIM process. Since the D90 of the MIM raw material powder is below 18um, the surface roughness of the sintered blank can be about Ra0.8, which brings convenience for subsequent grinding, polishing, electroplating and other processing. Therefore, metal powder injection molding can meet the harsh appearance requirements of watches and clocks.
3. Laptop application
Metal injection molding, a technology used to create small, complex metal parts, is a manufacturing process that Apple is using in the new Macbooks to save space inside the device, as the next-generation MacBook Pro may have an ultra-thin design. At the same time, it is reported that Zhaoli Technology Industry has prepared to provide metal injection mold hinge parts for 15-inch Macbook. It is expected that the new Macbook will be shipped in large quantities at the end of 2016 and 2017.
4. Application of electronic cigarette
Precision parts in electronic cigarettes are also processed by MIM. The metal processing process on the market is probably not faster than the MIM powder metallurgy injection process. As long as the specifications and the measured size of the sample are confirmed, efficient and fast processing can be achieved. This advantage has been reflected in mobile phone card trays and camera accessories.
In 2018, the sales of mid-to-high-end smartphones declined, and the number of MIM products used in smartphones was gradually decreasing. However, new advantages emerged in the e-cigarette industry. Most of the metal parts in e-cigarettes were processed by MIM. As a new product, electronic cigarettes are close to the taste of cigarettes and are more beneficial to quitters than cigarettes. Although the policy on e-cigarettes is not yet fully mature, the number of e-cigarette users has increased significantly, and there are currently at least 20.8 million e-cigarette users in the world. Consumer demand naturally brings an increase in the number of products, and as a MIM injection process that can achieve high-efficiency processing, it is essential to be applied to the processing of electronic cigarette accessories.
Among hardware accessories, MIM metal injection molding process is more efficient and precise than casting, machining, pressing and other processes. Because the products produced by metal injection molding are small and very fine stainless steel parts. Dimensional error, thin wall and hole thickness can achieve high accuracy. Complex part shapes, small sizes, and high yields are all advantages of the MIM process. At present, there are many related accessories in electronic cigarettes that involve MIM processing, such as cigarette holders, atomizer bases, shells, etc.
Application of MIM Technology (SKD11) on Hinge (Introduction to Process Flow)
According to the different properties required by customers, the selected materials are also different. Generally, MIM iron-based materials and tool steel materials such as SKD11 are used.
1. Iron-based materials
Generally, we use iron-based materials for general-purpose parts. After sintering, heat treatment and electroplating can meet the customer's performance. For products with complex shapes and structures, of course, mold structure design and precision machining have high requirements. We generally use plastic-based feeding. In this way, the sintering deformation can be reduced and the yield of the subsequent process can be improved.
2. SKD11 material
Gear products require high hardness, high wear resistance, and have special requirements for materials. We choose SKD11 material. This material has a narrow sintering temperature range, is very sensitive to temperature, and is not properly controlled. Reasonable temperature curve
The shape of the fixture is complex, and it also requires high hardness, high wear resistance and certain toughness. The SKD11 material has high hardness after sintering, and needs to be placed with a special sintering fixture.
Metal injection molding mim holder
Summary: Metal powder injection molding mim technology application areas
1. Computer and its auxiliary facilities: such as printer parts, magnetic cores, striker pins, drive parts;
2. Tools: such as drill bits, cutter heads, nozzles, gun drills, spiral milling cutters, punches, sockets, wrenches, electrical tools, hand tools, etc.;
3. Household appliances: such as watch cases, watch chains, electric toothbrushes, scissors, fans, golf heads, jewelry links, ballpoint pen clamps, cutting tool bits and other parts;
4. Parts for medical machinery: such as orthodontic frame, scissors, tweezers;
5. Military parts: missile tail, gun parts, warheads, drug cover, fuze parts;
6. Electrical parts: electronic packaging, micro motors, electronic parts, sensor devices;
7. Mechanical parts: such as cotton loosening machine, textile machine, crimping machine, office machinery, etc.;
8. Automobile and marine parts: such as clutch inner ring, fork sleeve, distributor sleeve, valve guide, synchronous hub, airbag parts, etc.