Injected Metal Assembly (IMA)

An Innovation in Joining

We developed IMA as an innovative, one-step manufacturing solution. It is a type of Insert Molding that outperforms most adhesives used for small component joining and assembly production and reduces manufacturing costs. Small components of just about any type of material can be joined including metals, ceramics, glass, fibers, paper, elastomers, and plastics.

The Advantages of IMA

• The bond requires no special surface preparation and has no peeling or thermal degradation issues common with conventional adhesives
• It performs well in harsh environments where only specialty adhesives and a few injection molding resins could maintain their integrity
• Part-to-part consistency is maintained over long production runs with tolerances of ±0.05 mm
• The process creates a strong mechanical lock that can withstand high loads (Zamak 3 zinc alloy is the most common bonding material used in IMA exhibiting a hardness of up to 82 BHN and shear and tensile strengths of 31 and 41 kpsi, respectively)

The IMA Process: Insert Molding

IMA uses molten zinc alloy to join components in much the same way as adhesives are used.

• The components needing to be assembled are positioned in their correct relationship by a custom-designed assembly tool
• After the tool closes, the components are aligned in their correct relationship, (usually taking less than 20 milliseconds), and molten alloy is injected under pressure into the intersection of the components
• The alloy solidifies in a fraction of a second, creating a strong, permanent mechanical lock between the components, free of flash or burrs. The completed assembly is then ejected from the tool ready for use

IMA Materials

The zinc alloy has a predictable 0.7% shrinkage, which is compensated for in the tool design.

• Zamak 3 zinc alloy is usually the top choice for bonding applications. Zamak 3 (zinc, aluminum, magnesium, and copper) contains (by weight) 4% aluminum and a small amount of magnesium
• Zamak 5 alloy, which also contains copper, has 15% greater strength, plus hardness and corrosion protection