What is Injected Metal Assembly?

High-pressure die casting is a fast, repeatable process that delivers quality metal components every time—but only if your component is properly designed. Many factors contribute to a successful design for high-volume manufacturing, and our team of engineers helps thousands of customers successfully launch new projects each year.

What is Injected Metal Assembly?

There are many methods for joining metal and other materials, and depending on your industry, certain considerations determine the most effective assembly method. If you are currently crimping, soldering, staking or welding components together, Injected Metal Assembly (IMA) could be a more efficient and reliable option.
What is Injected Metal Assembly?

The IMA process is a type of insert moulding that uses molten zinc alloy to join similar or dissimilar components and create a single assembled part that is strong, flash-free and repeatable. With production rates of up to 1,000 parts an hour, IMA bonding ensures consistently 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 lower than that of components joined by IMA.

How does IMA work?

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

Next, the tool closes and aligns precisely to hold the components in position while the molten alloy is injected into the cavity at the intersection of the components. The alloy—usually zinc because of its high strength, dimensional stability and load-bearing characteristics—solidifies in a fraction of a second and creates 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 high strength and stability, zinc alloys have predictable flow and shrinkage characteristics, enabling our designers to calculate the final dimensions of the injected metal joint with high accuracy. This allows tight tolerances to be achieved, improving the overall functionality of the part.

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

Dynacast can handle varying volumes, from as few as 5,000 pieces a year when required to 3 to 4 million parts per year with the support of automation and robotics. Production volume depends largely on customer needs.

When joining metal with a material such as plastic, how do you prevent the plastic from melting when it comes into contact with the injected molten metal?

With IMA, we can hold the die closed for up to one full second, depending on the fragility of the plastic, allowing heat to dissipate in the water-cooled tool. In addition to this cooling process, the low melting point of the 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 for insertion into the tooling for a low-volume production concept. Dynacast also offers a pull-ahead system, in which we build the tool to a certain stage and, if the produced parts are accepted by the customer, complete the tool.

How does IMA reduce cost?

IMA reduces costs by shortening production time and eliminating the need for secondary operations. While processes such as welding, soldering and crimping are often highly labour-intensive, IMA has the potential to be fully automated. When the part is ejected, flash-free and permanently bonded, it is ready for use.

What major markets are served by the IMA process?

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