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Learn how particle size and flow can optimize your metal injection process

Learn how particle size and flow can optimize your metal injection process

Metal Injection Molding (MIM) has grown rapidly in recent years. The estimated global annual growth rates are exceeding 11.9% from 2019 to 2025!

With the advancement from end users in the automotive, aerospace, consumer goods and medical industries, more complex and fine metal parts are in high demand.

To achieve the fineness and durability of metal parts that the end users are requiring, domestic and international MIM manufacturers are adopting stringent methodologies to examine the metal powders they use.

To improve the quality of your end products, you must understand below five key steps of the Metal Injection Molding Process (MIM).

Five key steps of the Metal Injection Molding Process (MIM)

Process chart

Metal injection molding manufacturers seeking to improve production quality can start with Step 1: Metal Powder Forming, Step 2: Raw Material Forming and Step 5: Sintering.

Step 1: Metal powder molding

The size distribution and shape of the particles directly affect the results of sintering. Spherical powders will have a higher packing density and are usually the most popular among MIM manufacturers. To have the best performance and quality of your products, monitoring powders must be a part of your manufacturing process. If your powder is spherical, it will work best in the fifth step of sintering because it has more contact surfaces, less sintering time, and avoids shrinkage, allowing you to finish the product more accurately and delicately.

Most manufacturers currently use laser particle size analyzers and image analyzers to determine the particle diameter of the metal particle size and particle shape. They also use this method to compare the atomized metal powder manufactured via different processes and select the most suitable powder.

Using automated particle size image analyzer can help you effectively analyze the shape and size of the powder.  Monitor the powder properties can help you optimize the manufacturing process.

Step 2: Raw material pallet molding

The fluidity of the raw material has a decisive influence on the quality of the final product! The fluidity of the raw material affects the uniformity of the molten raw material, the speed of the inflow into the mold, and the mechanical properties of the green part after cooling. Simply put, the fluidity of the powder determines whether it is easy to filler. And how to choose good plastics to increase mobility is key to improving your production advantage.

Flow characteristics are determined by a number of factors, including binder and solids composition ratio, particle size, size distribution and shape, temperature and flow rate etc.

By using a capillary rheometer, you can analyze the flow and deformation characteristics of the material under relevant conditions, such as pressure, shear rate, and temperature. The data can help you choose the best plastic and metal ratio, optimize the fluidity of raw materials and achieve the best production results.  You can then avoid situations such as shark skin on metal surface, uneven injecting, and high injection pressure.

Process chart

Step 5: Sintering

The particle size shape affects the packing density and has an effect on the metal strength after sintering! How strong is the metal after sintering? In the last step, you can use the X-ray Diffraction to observe the mineral structure of the metal and test the strength of the metal, which is also called the residual stress.

In summary, a good metal injection molding analysis solution should provide the following benefits:

  • Optimize particle ratio to minimize part shrinkage and void formation
  • Ensure the dimensional stability of the appropriate raw material machinability after forming
  • Optimize adhesive properties for flowable and degreasing properties
  • Ensure the consistency of metal powder properties
  • Powder supply, inspection of incoming materials to ensure procurement quality
  • Measuring the strength of the formed metal

To learn more about these solutions, access the following links: