Injection moulding MIM process features and applications

Metal Powder Injection Molding (MIM) is a modern plastic injection molding technology that has entered the field of powder metallurgy, and has formed a new powder metallurgy near net forming technology. The powder metallurgy injection molding process is close to the powder metallurgy technology. First, the solid powder and organic binder are uniformly mixed together, and then they are heated at 150 ℃ for plasticization. Then, they are injected into the tooling with machines, and then solidified by degrease furnace, the binder in the preform is removed by thermal decomposition, Finally,precision parts are produced by sintering like normal powder metallurgy.

The MIM process is divided into four unique processing steps (mixing, molding, degreasing and sintering) to realize the production of parts, and finally decide whether to conduct surface treatment according to the product characteristics.

Process characteristics

1.Powder particle size

 The powder size for MIM injection molding is very small, and the particle size of raw material powder used is 2-15um. However, the particle size of traditional powder metallurgy raw powder is mostly 50-100u m. Therefore, MIM is more expensive than PM powder.

2.cost

MIM injection molding can produce precise part geometry without cutting and secondary processing. It can produce high-density and highly complex structural parts and reduce costs for the whole production.

3.Component design freedom

The use of MIM injection molding has almost no geometric restrictions, and the 3D design is very free, so the finished product can have complex structure and diverse functions

4. physical property

The density of structural parts varies greatly. The friction between PM powder and tools will make the parts uneven. The MIM injection molded parts are uniform in all directions, and the relative density can reach 95% - 99%. The sintering temperature of MIM is much higher than that of PM, the strength, toughness and wear resistance of MIM injection molding are significantly higher, and the utilization of raw materials is high.

MIM products applications

MIM products are widely used in electronic information engineering, biomedical equipment, office equipment, automobiles, machinery, hardware, sports equipment, weapons aviation and other industrial fields.

1. Aerospace industry: aircraft wing hinge, rocket nozzle, missile tail, ceramic turbine blade.

2. Automobile industry: ignition control lock components, turbocharger rotor, parts for airbag, parts for automobile lock, valve guide rail components, automobile braking device components, automobile sunscreen shed components, automobile door lifting system, oil supply system sensing small parts, etc.

3. Electronics: disk drive components, cable connectors, electronic tubes, electronic packages, heat sink materials, printer parts, optical communication ceramic joints, mobile phone structural parts, etc.

4. Military industry: mine rotor, gun plate trigger, armour piercing bullet core, quasi constellation, cluster arrows, small arrows, etc.

5. Medical treatment: orthodontic brackets, internal suture needles, living tissue sampling forceps, radiation shielding shields, medical device parts, etc.

6. Daily necessities: watch case, watch strap, watch buckle, golf head and socket, sports shoe buckle, sports machinery parts, document binding punch, jewelry chain ring, etc.

7. Machinery industry: textile machines, crimping machines, profiled milling cutters, cutting tools, micro gears, etc.