The basic process is: first, mix the solid powder and organic adhesive evenly, and put the plastic in (~ 150) the heated particles in the state are solidified with the injection molding machine entering the mold cavity, as well as the chemical or thermal decomposition method of forming blank adhesive removal, and finally the final product is sintering.Compared with the traditional process, injection molding has high precision and good uniformity,With good performance and low production cost, its products are widely used in electronic information engineering and biology.Medical equipment, office equipment, vehicles, machinery, hardware, sports equipment, clocks, weapons, aerospace and other industries.
It is generally believed that the technology will lead to the development of parts forming and processing technology, a revolution, known as \"the most popular parts forming technology\" and \"21st century forming technology \".\\ \"Metal powder injection mold
ing technology is a variety of plastic molding technology, polymer chemistry, metallurgy and metal materials () technology.Discipline and crossPenetration of products, the use of injection molds can be made by sintering high blank and fastdensity, high-Precision, threeThe size structure of complex shape parts, quickly and accurately embodies the design idea into a certain structure, the functional properties of the product,Production parts, new changes have taken place in the manufacturing industry.
The technology not only has the advantages of less traditional powder metallurgy process, no cutting or less cutting, high cost, but also overcomes the uneven texture, low mechanical performance and thin structure of traditional powder metallurgy products.Disadvantages such as difficult wall forming and complicated structure are especially suitable for mass production of products with small, complex and special requirements for metal parts.MIM process: mixed metal adhesive you injection molding your sintering process of oil removal.
(1) metal powder.
The particle size of MIM process used in metal powder is generally 0.5 ~ 20¼m.In theory, the finer the particles, the larger the surface area, the easier it is to form and sintering.The traditional powder metallurgy process uses thick powder above 40 μm.
(2) organic adhesive.
The role of organic adhesives is to glue metal powder particles to give the mixture fluidity and lubrication after heating in the injection molding machine barrel, which is to bring the carrier of powder flow.Therefore, choosing the right adhesive is the key to powder injection molding.The requirements for organic adhesives are as follows: \"The mixture of less used and less used adhesives can
produce better flow properties;A does not react in the process of removing the adhesive, and the metal powder cannot afford any chemical reaction;B.
easy to remove, no carbon residue in the product.(3) Mixing.Mix the metal powder and organic adhesive evenly and make various raw materials into injection molding mixture.The uniformity of the mixture directly affects its fluidity, thus affecting properties such as injection molding process parameters and final material density.
(4) injection molding.
The process of this step is the same as the plastic injection molding process, and the equipment conditions are basically the same.During the injection molding process, the injection molding machine cylinder in the mixture is heated into the flow properties of the plastic material and, where appropriate, rough under pressure.The injection molding blank should be uniform in appearance, so that the product will shrink evenly during sintering.
(5) extraction of blank shape.
The blank must be removed before the sintering contained in the organic adhesive, a process called extraction.During the extraction process, it is necessary to ensure that the different parts of the coarse material gradually pass along the small channel between the particles without reducing the strength of the coarse material.The elimination rate of adhesive generally follows the diffusion equation.
Make the porous sintering density of fat a blank contract and performance for certain products.Although the performance of the product is related to many process factors before sintering, in many cases, the final sintering process has a great or even decisive impact on the microstructure and performance of the product.(7) Post-processing.For the size requirements of more complex parts, the necessaryprocessing.
This process is the same as the traditional metal heat treatment process.Application field of injection molding technology: (1) Computer and its auxiliary facilities: such as printer parts, core, pin burning shaft, drive parts, etc.;(2) tools: such as drill bit, Blade, nozzle, gun drill, screw cutter, punch press, socket, wrench, power tool, manual tool, etc.
;(3) household appliances: Case, bracelet, electric toothbrush, scissors, electric fan, golf ball head, jewelry chain, ring, ball-Zero components such as pen hoop and knife head;(4) medical mechanical parts: such as dental orthopedic racks, scissors, tweezers, etc.;(5) military parts: missile wings, guns, bullets, liners, and reference credit departments.;(6) electrical part: Electronic Packaging, miniatureMotor, electronic components, sensors, accessories, etc.
;(7) mechanical parts: such as loose cotton, spinning machine, winding machine, office machinery, etc.;(8) shipment of auto parts: such as clutch inner ring, fork pull Group, voltage divider group, Valve Guide group, synchronous hub, airbag and other parts