FAQs on Metal Injection Molding (MIM)

What alloys can be metal injection molded by APP?

APP primarily uses steels and stainless steels, however, copper, heavy alloys, tool steels, and even titanium are workable.

What is the difference between conventional MIM and ProtoMIM®?

ProtoMIM® is the quickest, most economical method to produce real MIM parts. Unlike traditional metal injection molding, ProtoMIM® is a rapid prototype that acts as a bridge which is often used for early stages of validation. Once confident, your design is released to tool build and components are delivered with in 3-6 weeks.

Can APP metal injection mold aluminum?

Although, it has never been significantly commercialized, aluminum has been used in metal injection molding.

Why would I want to use ProtoMIM®?

ProtoMIM® is perfect for initial part validation. Our proprietary technology acts a bridge tool to your initial pilot builds while your production tool is in design and build. ProtoMIM® allows you to do testing and make any necessary changes before you head into production.

What are the challenges with using Titanium in MIM?

Due to its reactive extremely reactive nature, titanium can pick up oxygen and carbon during metal injection molding if the proper precautions are not followed.

Can APP manufacture threaded components?

Yes, APP can manufacture both internal and external threads on MIM components. The threads can either be done as a secondary or incorporated into the tool. The use of as-molded threads will depend upon the volume of components to be manufactured and the tolerance requirements of the threads.

What is the typical size for a metal injection molded component?

MIM components are typically 10-20 gram, but can be as small as a few milligrams or as large as 250 grams. MIM components typically fit in the palm of your hand.

What feature does APP look for to make the MIM process the most successful?

To prevent extra fixture expenses, APP prefers a flat surface to set the part for sintering. For MIM parts without a flat surface, we build ceramic support to limit distortion during the sintering process.

What is a typical wall thickness for MIM components?

MIM components typically have a wall thickness of 0.050” to 0.400”. Wall thickness less than 0.010” and larger than 0.600” should be avoided.

Can MIM components be electroplated the same as conventional metals and alloys?

Yes, MIM components can be plated the same way that other metals are processed. The MIM material must have at least a density of 94% to eliminate any porosity that could trap plating solutions that could result in undesirable corrosion in the future.

Why is APP unique in the MIM industry?

APP has been a technical leader for major OEMs for over 20 years. With in-house P.E. metallurgists and material scientists, we can develop custom feedstocks to meet your specific application needs. Our primary focus is you and your product goals. We believe in collaboration and appoint a program engineer to ensure your components are produced at price and on-time.

Are there any MIM alloys that are implantable?

Yes, MIM titanium alloys and ASTM F2886 (Co-Cr) alloys are known to be implantable. If wrought stainless steel is used in implantable applications, 316L stainless steel can be substituted.

Can APP metal injection molded parts be over molded with plastics?

Yes, APP has the capability to over mold parts. The key to over molding MIM components limiting parting lines in the area that the over molding tool will shut off.

Are the properties of MIM materials the same as wrought properties?

Although slightly inferior to wrought properties, MIM properties show superiority to most cast alloys. Typically, 90-95% wrought, MIM can be produced to equal or succeed wrought proprieties when the components are hot isostatic pressed (HIP).

Can APP utilize the same tool for multiple alloys?

Yes, APP can manufacture components from multiple alloys in the same tool. This is highly successful during prototyping to define the proper alloy for an application. This is also done with production tools, but the tool may require special inserts in critical dimension areas.

Why are 316L stainless steel and MP35N alloys softer than wrought alloys of the same stoichiometry?

When these alloys are processed using conventional methods, they are machined or worked and results in strengthening. MIMed 316L and MP35N are solution annealed after sintering, therefore making them softer than their wrought counterparts.

How much shrinkage does APP material have during processing?

Depending on the alloy and starting material, APP’s tooling shrink ranges from 1.17 to 1.25.

Does APP offer secondary processing to their MIM components?

Yes, APP not only metal injection molds components, we also machine, heat treat, and surface coat according to your requirements.

Can APP utilize tooling from other MIM facilities?

Yes, APP is unique in that we manufacture our own MIM feedstock and can process Catamold tools.


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