Can zinc cast housings meet EMI shielding requirements?
Can Zinc Cast Housings Meet EMI Shielding Requirements?
EMI Shielding Requirements for Electronic Housings
EMI (Electromagnetic Interference) shielding is essential in electronic devices to prevent disruption from internal or external electromagnetic fields. Effective EMI shielding protects circuit integrity, meets regulatory compliance (FCC, CE), and ensures device reliability. Enclosures for automotive, telecom, medical, and consumer electronics must often meet stringent EMI attenuation levels.
Why Zinc Is Effective for EMI Shielding
Zinc alloys, particularly Zamak 3 and Zamak 5, are ideal for die cast housings requiring EMI protection due to their high electrical conductivity and seamless casting properties.
Key performance benefits include:
Electrical Conductivity: Zamak alloys offer ~27% IACS conductivity, sufficient for attenuating electromagnetic fields in the MHz–GHz range.
360° Shielding: Zinc die casting enables one-piece housings with minimal seams or gaps, reducing EMI leakage paths.
Integrated Grounding: Cast-in bosses or flanges can be used for direct PCB grounding, enhancing shielding continuity.
Precision Interfaces: Tight tool and die tolerances ensure secure closures and gasket interfaces.
Design Strategies for EMI Shielded Zinc Housings
To achieve consistent shielding performance, zinc enclosures should incorporate:
Gasket grooves: For conductive or EMI shielding gaskets (e.g., silicone with silver fill)
Flat sealing surfaces: Achieved through CNC machining for optimal compression and contact
Plating or coating: Nickel plating or conductive chromate coatings can enhance surface conductivity and corrosion protection
Multi-chamber internal partitions: Isolate critical components from radiated noise
Zinc housing surfaces can also support additional shielding features such as embedded conductive threads or metalized coatings if required.
Performance Testing and Validation
Neway offers full validation support for EMI requirements, including:
Shielding effectiveness testing per IEEE 299 or MIL-STD-285
Surface conductivity verification for plated finishes
Flatness and interface pressure validation for gasketed assemblies
Housing integration with assembly of conductive fasteners and ground terminals
Neway’s Zinc Die Casting Solutions for EMI Shielding
Neway provides complete EMI-compliant enclosure production with:
High-precision zinc die casting for seamless shielding
Optimized tooling to control wall thickness and closure fit
Post-cast plating, machining, and inspection
Functional sealing and EMI gasket integration in production assembly
