Metal Injection Molding Service

What is Metal Injection Molding?

Metal Injection Molding (MIM) is a manufacturing process that combines the principles of plastic injection molding and powder metallurgy to produce intricate and complex metal parts.

Metal Injection Molding creates high-quality end products with complex geometries, metal injection molding can produce high volumes of smaller, complex parts at a cost-effective price, develop metal prototypes and components with minimal waste. It’s often used in industries such as aerospace, automotive, medical devices, and electronics, where intricate and small metal components are required.

metal injection molding

Pros and Cons of Metal Injection Molding

Before we utilize metal injection molding process, we should fully understand its advantages and disadvantages, foster strengths and circumvent weaknesses, to achieve the output of better quality custom metal parts.

Pros of Metal Injection Molding

    • Complex Shapes: Easily creates intricate and complex metal parts.
    • High Precision: Offers tight tolerances and excellent surface finishes.
    • Cost-Efficiency: Reduces material waste and labor costs compared to traditional machining.
    • Versatility: Works with various metals and alloys.
    • Consistency: Produces parts with consistent quality.
    • Reduced Post-Processing: Minimal additional finishing required.
    • Scalability: Suitable for both small and large production runs.

Cons of Metal Injection Molding

    • Material Limitations: Limited to metals and alloys that can be powdered.
    • Tooling Costs: Initial mold and tooling setup can be expensive.
    • Size Constraints: Not ideal for very large parts.
    • Surface Imperfections: May require additional polishing for a smoother finish.
    • Not Suitable for all Applications: Unsuitable for critical load-bearing or high-stress components.

Metals in Injection Molding

Metal Injection Molding can be used with a wide range of metal materials and alloys. Some common materials used in metal injection molding include:

    • Aluminum Alloys: Aluminum 6061, Aluminum 7075
    • Stainless Steel Alloys: 316L Stainless Steel, 17-4 PH Stainless Steel, 440C Stainless Steel, 304 Stainless Steel
    • Tool Steels: M2 Tool Steel, D2 Tool Steel, A2 Tool Steel
    • Carbon Steel Alloys: 1018 Carbon Steel, 1045 Carbon Steel, 1095 Carbon Steel
    • Low Alloy Steels: 4140 Low Alloy Steel, 8620 Low Alloy Steel
    • High-Speed Steels: M42 High-Speed Steel, M4 High-Speed Steel
    • Copper Alloys: Copper-Tin Alloys, Copper-Nickel Alloys
    • Titanium Alloys: Ti-6Al-4V (Grade 5), Ti-6Al-7Nb
    • Tungsten Alloys: Tungsten-Nickel-Copper Alloys
    • Precious Metal Alloys: Gold Alloys, Silver Alloys
    • Magnetic Alloys: Soft Magnetic Alloys (e.g., 49%Ni-Fe)
    • Cobalt Alloys: Cobalt-Chromium Alloys (e.g., CoCrMo)
    • Iron Alloys: Sintered Iron, Soft Magnetic Iron, Ductile Iron
    • Carbide Materials: Tungsten Carbide (WC), Cemented Carbide
    • Cermet Materials: Titanium Carbide (TiC) Cermet, Chromium Carbide (Cr3C2) Cermet

How Does Metal Injection Molding Work?

The metal injection molding process involves several distinct stages, each playing a crucial role in transforming raw materials into finished metal parts with intricate shapes and high precision. Here’s an overview of how metal injection molding works.

Feedstock Preparation

In this stage, fine metal powders are combined with a thermoplastic binder material and any necessary additives. The goal is to create a homogeneous mixture known as feedstock. The metal powders can be selected based on the desired properties of the final part.

Injection Molding

The feedstock is heated until it becomes a viscous, flowable material. It is then injected into a mold cavity under high pressure, similar to plastic injection molding. The mold is designed to replicate the shape and features of the final metal part.

Green Part Formation

The injected feedstock solidifies inside the mold cavity, creating a “green part.” This green part consists of the metal powder particles held together by the binder material. It retains the shape of the final part but is porous.


The green part is subjected to a thermal process known as debinding. During debinding, the thermoplastic binder is removed from the green part. This can be done through solvent debinding, catalytic debinding, or thermal debinding, depending on the materials and equipment used.

Brown Part Formation

After debinding, the part is referred to as a “brown part.” It is still porous but no longer contains the thermoplastic binder. The brown part is fragile and must be handled carefully to avoid damage.


The brown part undergoes high-temperature sintering in a controlled atmosphere, typically in a furnace. During sintering, the metal powders fuse together, and the part densifies. This process eliminates the remaining porosity and results in a solid metal part with the desired mechanical properties.

Post-Processing (Optional)

Depending on the specific requirements of the part, additional post-processing steps may be performed after sintering. This can include machining, heat treatment, surface finishing, or other secondary operations to achieve the desired final properties and surface quality.

Quality Control and Testing

Throughout the MIM process, quality control measures are implemented to monitor dimensional accuracy and mechanical properties. Testing methods such as metrology, mechanical testing, and metallurgical analysis are used to ensure the parts meet specifications.

Packaging and Shipping

Once the parts have passed quality control and any necessary post-processing steps, they are packaged and prepared for shipment to the customer or assembly line.

These stages collectively transform the raw materials into finished metal parts, allowing MIM to produce complex and high-precision components with a wide range of applications across various industries. The process requires careful control and optimization of each stage to achieve the desired part quality and performance.

Applications of Metal Injection Molding

Metal injection molding is a versatile manufacturing process with a wide range of applications across various industries. Some common applications of metal injection molding include:

  • Medical and Dental Devices:
    Surgical instruments, Orthodontic brackets, Dental implants
  • Aerospace and Defense:
    Small complex aerospace components, Missile and munition components, Firearm components
  • Automotive:
    Engine and transmission parts, Fuel system components, Sensors and actuators
  • Electronics:
    Connectors and terminals, EMI shielding components, Miniature switches
  • Consumer Goods:
    Watch components, Lock and key components, Precision hinges and clasps
  • Industrial Equipment:
    Valves and fittings, Pump components, Gears and gearboxes
  • Textile Machinery:
    Nozzles and guide pins, Needle holders, Spinnerets for fiber production
  • Energy and Power Generation:
    Turbine blades and nozzles, Heat exchanger components, Electrical connectors and contacts
  • Telecommunications:
    Antenna components, Connector housings, Waveguide components
  • Fire Sprinkler Systems:
    Sprinkler heads, Valve components

These are just a few examples, and metal injection molding is continually expanding into new applications as technology advances and the demand for high-precision, complex metal parts grows. MIM’s ability to produce parts with intricate geometries and tight tolerances while minimizing material waste makes it an attractive choice in industries where traditional manufacturing methods may be less cost-effective or practical.

Start a Metal Injection Molding Project or Not?

Starting a metal injection molding (MIM) project involves a careful assessment of your specific needs and objectives. Here are steps to determine whether MIM is the right technology for your custom metal parts projects:

Part Complexity and Geometry

Evaluate the complexity of the desired part. Metal injection molding excels at producing intricate and complex shapes with high precision. If your part has intricate features, thin walls, or complex geometries that are challenging for traditional manufacturing methods, MIM may be suitable.

Material Requirements

Consider the material properties required for your part. Metal injection molding offers a wide range of metal materials, including stainless steel, titanium, copper alloys, and more. If your part needs specific material properties like high strength, corrosion resistance, or magnetic properties, MIM can be a good choice.

Volume and Cost Considerations

Assess the required production volume. Metal injection molding is cost-effective for medium to high production volumes but may not be economical for very low quantities. If you need a large number of parts, MIM’s efficiency can make it a cost-effective choice.

Tight Tolerances and Surface Finish

Determine if your part requires tight tolerances and a smooth surface finish. Metal injection molding can achieve tight tolerances and excellent surface finishes, reducing the need for extensive post-processing.

Prototype and Lead Time

Consider your timeline. Metal injection molding projects typically have longer lead times due to tooling and sintering processes. If you require rapid prototyping or extremely quick turnaround, other manufacturing methods may be more suitable for initial stages.

Budget and Cost Analysis

Conduct a cost analysis to determine if metal injection molding aligns with your budget. Consider not only the per-part cost but also tooling and setup costs. MIM’s cost-effectiveness becomes more apparent with larger production runs.

Testing and Validation

Consider producing prototypes or conducting validation tests to confirm that MIM-produced parts meet your performance requirements. This can help mitigate any unforeseen issues.

Metal Injection Molding Supplier

Collaborate with Sungplastic, a specialized custom metal parts manufacturer equipped with excellent professionals, designers and workers and advanced technical machinery, you will get a cost-effective solution to manufacture your custom metal parts with high performance and high precision.

Additionally, except for metal injection molding, we also provide metal CNC machining, metal casting, sheet metal stamping, metal 3D printing service and etc. Sungplastic will give the best suggestions if you can share your ideas or send samples or design drawings of your desired metal parts.

Do you have any questions about metal injection molding? Please get in touch with us directly!

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