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What is Injected Metal Assembly?

There are many different methods of joining metal and other materials, and depending on your industry, there certain considerations that determine the most effective method of assembly. If you’re currently crimping, soldering, staking, or welding components together, injected metal assembly (IMA) could be a more efficient and reliable option for you.


What is injected metal assembly?

The IMA process uses a molten zinc alloy to join similar or dissimilar components together and create a singular assembled part that is strong, flash-free, and repeatable. With production rates up to 1,000 parts an hour, IMA adhesion ensures consistent higher quality parts while keeping manufacturing costs low.


The uneven heating and cooling of the welding process produces brittle joints that are vulnerable to stress. As a result, their fatigue strength is far less than that of components joined by IMA.


How does IMA work?

First, the components that need to be assembled are placed into the machine in a custom designed casting tool. These custom tools are able to accommodate components of various shapes, sizes, and materials.

Next, the tool closes and precisely aligns to holds the components in their precise position while the molten alloy is injected into the cavity at the intersection of the components. The alloy—usually zinc for its high strength, dimensional stability, and load-bearing characteristics—solidifies in a fraction of a second and produces a strong, permanent lock between the components. Finally, the tool opens and the assembled part is ejected from the die. The ejected component is flash-free, requires no secondary operations, and is stronger than conventionally joined metal components.


When the zinc alloy is injected, it fills the cavities in the custom tool and hardens to create a permanent bond between the components.


In addition to being high in strength and stability, zinc alloys are predictable in their flow and shrinkage characteristics, enabling our designers to calculate with high accuracy the final dimension of the injected metal joint. This allows for exacting tight tolerances to improve the overall functionality of the part.

What is the required volume for the IMA process to be viable?

Dynacast is capable of running varied volumes, down to 5,000 pieces a year if need be and up to 3 to 4 million parts per year with the help of automation and robotics. The volume of production is largely dependent upon the needs of the customer.

When joining metal and a material like plastic, how do you keep the plastic from melting when it comes in contact with the injected molten metal?

With IMA, we are able to hold the die closed for up to a whole second, depending on the fragility of the plastic, and allow the heat to dissipate in the water-cooled tool. In addition to this cooling process, the low melting point of injected metal prevents thermal degradation of the parent materials.

Can you prototype an IMA part?

Yes. While we cannot create a complete part before production begins, Dynacast can build simple “soft tooling” and create part-specific cavity blocks to insert into the tooling for a low production concept. Dynacast also offers a pull-ahead system where we build the tool to a certain point, and if parts produced are accepted by the customer, we complete the tool.

How does IMA reduce cost?

IMA reduces cost by cutting production time and eliminating the need for secondary operations. While processes like welding, soldering, and crimping are often very Labour intensive, IMA has the potential to be fully automated. When part is ejected, flash-free and permanently bonded, it is ready for use.

What are major markets served by the IMA process?

The IMA process serves virtually any industry and any application. Automotive, telecommunications, electronic components, hardware and appliances, industrial controls, and military industries often utilize parts crafted by the IMA process.


Drill bit joined together using IMA

Piston Carrier joined together using IMA


Would you like to learn more about the IMA process and practical applications? Fill out the form below to download our free webinar!



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Last updated 03.22.2021