Case Study: Nozzle Assembly

Process: Metal injection molding
Material: 316L stainless steel
Density: >7.6 g/cm³
Tensile Strength: 520 MPa
Yield Strength: 175 MPa
Hardness: 67 HRB

2014 Grand Prize: Nozzle Assembly
2014 Grand Prize: Nozzle Assembly

End Use and Function

This nozzle assembly is composed of a three-piece assembly—nozzle interface, outer nozzle, and metal collar—that go into high-end sound-isolating earphones that enable user-customizable frequency responses. The challenge involved meeting the cost demands of the highly competitive professional-audio market while maintained a cosmetically perfect surface—critical in a consumer product—with a clear exterior.

Fabrication

Made via metal injection molding (MIM) from 316L stainless steel, each component nests within another component utilizing either locking lugs or fine metric threads to join the assembly seamlessly.
The parts have a density >7.6 g/cm³, an ultimate tensile strength of 520 MPa, a yield strength of 175 MPa, an elongation of 50%, and an apparent hardness of 67 HRB.

Results

MIM was the ideal choice, as alternative fabrication methods, such as die casting or machining, could not have provided the precision needed at a reasonable cost, nor been able to provide the required material performance.

  • MIM is most effective and efficient with small, high tolerance, and extremely complex components—an accurate description of the three part assembly.
  • Necessary geometric details, material strength properties, and end-use precision were achieved while providing the user with an effective customizable product.
  • Significantly lower component price—allowed the OEM to enjoy a competitive advantage as it launched its product.