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Metal Injection Molding

A reliable source for Metal Injection Molding information and leading Metal Injection Molding Companies & Manufacturers.

Metal injection molding (MIM) is a manufacturing process for fabricating small and precise metal components using finely-powdered metal, blended with a binder (binding agent), then solidified. Read More…

Metal Injection Molding Metal injection molding, also called MIM, is a low cost, high volume manufacturing process that produces custom metal parts near to net shape.
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Leading Manufacturers

Tulsa, OK  |  918-663-7511

Since 1967, PSP has been a leader in small, intricate custom powdered metal parts for a wide range of industries, such as Sports & Recreation, Power Tools, Industrial Equipment, Oil & Gas.

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Precision Sintered Parts $$$

St. Marys, PA  |  814-781-1033

Our powdered metal services have been around for 6 decades. Innovative Sintered Metals produces powdered metal parts from a wide variety of materials. Our powdered metal knowledge and sintered expertise result in the best powder metal parts available. ISO/TS 16949: 2009 certified. We are a very diversified organization serving the commercial construction, pump, automotive, appliance & lock industries.

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Innovative Sintered Metals, Inc. $$$

Los Angeles, CA  |  888-663-8256

Our metal injection molding cannot be topped! We have years of field industry experience that we want to put to work for you. It is our mission that we will be able to offer high quality customer service as well as products that will withstand the tests of time to provide lasting value. For more information on what we may be able to do for you, get in touch with our customer service department today!

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PSM Industries $$$

Sykesville, PA  |  814-894-2461

As a powder metal specialist, we will gladly consult with you about any gears, pulleys and sprockets you need. Symmco makes sintered stainless parts: cams, food processing machinery parts, gears, structural components. In inventory: SAE 841-sintered bronze, bearings, cored and solid bar, rectangular plate. We have a capacity of 5 tons through 750 tons. Contact us today to learn more about our capabilities.

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Symmco Incorporated $$$

Garden Grove, CA  |  714-898-9151

With over 30 years of experience, Poly Processing Company has become a leading manufacturer of rotationally molded poly tanks, plastic storage tanks, chemical tanks, double wall tanks, chemical storage tanks and miscellaneous tanks. We offer cost effective solutions to your plastic tank needs.

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Synertech P/M, Inc. $$$
placeholder image Precision Sintered Parts Innovative Sintered Metals, Inc. PSM Industries Symmco Incorporated Synertech P/M, Inc.

The metal injection molding cycle starts with the creation of the feedstock (the raw materials used to produce another material or item) by combining a binder made up of lubricants, polymers, waxes, and surfactants with a smooth metallic powder. The final feedstock is then ground into granules. Next, the feedstock is heated using an injection molding machine before being injected under pressure into a mold cavity. Time is then allowed for the molten feedstock to cool and solidify. A portion of the feedstock becomes a very porous brown substance once the binder components are eliminated. This brown component is subsequently sintered into more solid material and normally achieves over 95% of the density of the rest of the material, with no pores.

Metal Injection Molding Considerations

Metal injection molding can process almost any metal manufactured in an appropriate powder form. The adhering oxide film constantly presents on the surface of aluminum metal makes it an exception, as it prevents the sintering stage of the metal injection molding process. Numerous popular and less-common metals and their alloys are included in the list of metals that have been utilized in the metal injection molding process. The various metals processed through MIM include high-speed steels, superalloys, magnetic alloys, stainless steels, cemented carbides (hard metals), magnetic alloys, and intermetallic alloys.

Injection Molded Parts

Several factors make the choice of the binding particle used significant, including a powder’s density, the amount of metal contained in the feedstock, etc. Another surprising factor in selecting a binder is the shape of its particles. Typically, a spherical or nearly-spherical shape is preferable for MIM processes, although this also increases the chance of the skeleton deforming during the debonding stage. Coating each particle’s surface with a binder is another major factor to consider during the mixing process.

Metal Injection Molding Flow Diagram

The feedstock mix is converted into solid pellets through a process known as granulation during the molding stage. To fabricate the best products, the temperatures of various metal injection machine components, including the nozzle used to inject the feedstock mix into the die and the screw which extrudes the mix through the die cavity, must be carefully maintained. The temperature of the die itself must also be managed, and it needs to be kept low enough to guarantee that removed components are set and solid.

Debinding, which involves removing the binding agent from the mold, is another crucial factor in metal injection molding, requiring extremely precise management. Two different processes are typically involved during debonding. In the first process, heat is applied to the mold and other equipment components to disintegrate any remaining feedstock material found on them. The second debinding procedure, which is only applicable to specific binder systems, involves dissolving the binder agent using suitable solvents like trichloroethane; again, heating is typically needed as the last step to complete the elimination of the binder material and solvent by evaporation.

Injection Molding Machine

Sintering creates a solid mass of material by applying pressure and heat to it without melting it to the point of liquefaction. Sintering is what provides a final product its strength. The procedure is done at temperatures usually below the metal’s melting point in controlled-environment furnaces in a vacuum and is crucial to prevent oxidation of the metal. The specific atmosphere of the sintering furnace depends on the metal type. For many metals, a simple atmosphere of hydrogen is sufficient. Still, for steel, where carbon serves as a crucial alloy ingredient, the atmosphere must contain one or more carbon compounds to maintain equilibrium with the steel, not to change this material’s properties.

Advantages of Metal Injection Molding

  • Large production runs of metal components with intricate geometries and features are supported by metal injection molding. It works well for the high-volume production of small, precise parts with exact tolerances.
  • Metal injection molding can precisely manufacture features, including internal and external threads, undercuts, holes, markings, and slots, without the need for additional machining or fabrication steps.
  • Few limitations are placed on an item’s design through MIM. This process allows the opportunity to produce a wide range of shapes.
  • Metal injection molding provides a smooth surface that can be improved through polishing.
  • Metal injection molding can produce multiple parts from a single material piece.
  • A variety of materials can be used in metal injection molding.

Disadvantages of Metal Injection Molding

  • Metal injection molding can be pricey for modest production requirements.
  • MIM may not be the best method for creating challenging metal fabrications.
  • Metal injection molding is appropriate for small and medium-sized parts. Large part shaping, however, can reduce the mold’s ability to function properly and the furnace’s capacity, increasing process costs.

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