How to Choose the Right Material for Custom EMI/RF Shielding Can (A Manufacturer’s Guide)

Advantages:

High Strength & Rigidity: Provides excellent structural support, resists deformation.
Excellent Spring Properties: Especially SUS 301, ideal for clips/snaps requiring tension or covers needing frequent removal (e.g., test points).
Good Corrosion Resistance: SUS 304 performs excellently in most environments.
Cost-Effective: Generally less expensive than copper alloys, with relatively stable raw material costs.
Good Magnetic Shielding (H-field): Due to its ferromagnetic properties, offers better low-frequency magnetic field shielding than non-magnetic copper alloys.

Disadvantages:

Lower Electrical Conductivity:Compared to copper alloys, Electric Field Shielding Effectiveness (E-field SE) is slightly weaker at higher frequencies (though usually still sufficient for most requirements).

High Work Hardening Rate:Especially pronounced in SUS 301, requiring more frequent die maintenance or intermediate annealing, increasing difficulty and cost for complex deep drawing.
Solderability Challenges: Typically requires Nickel Plating to ensure good solderability and prevent rusting.
Best For: Applications needing high strength/rigidity, good corrosion resistance, and cost sensitivity; requiring low-frequency magnetic shielding; spring contacts/clips. Common in consumer electronics, industrial controls, automotive electronics main structures.

Advantages:

Excellent Corrosion Resistance:Nickel content gives corrosion resistance better than brass, approaching stainless steel. Silvery appearance.
Good Electrical Conductivity: Better than stainless steel.
Good Formability & Solderability: Easy to process, good soldering performance.
Moderate Strength: Falls between brass and stainless steel.

Disadvantages:

Higher Cost: More expensive than stainless steel and brass.
Poor Magnetic Shielding: Non-magnetic.
Best For: Applications needing a balance of good corrosion resistance and conductivity, often requiring a silvery appearance. Common in medical devices, marine environment equipment, high-end consumer electronics visible parts.

Advantages:

Very High Strength & Superior Spring Properties: Better elasticity and fatigue resistance than brass and most stainless steel (except SUS301). Ideal for spring contacts, battery clips, and frequently removed covers.
Good Electrical Conductivity: Better than stainless steel, provides good E-field shielding.
Good Corrosion & Stress Relaxation Resistance: Maintains elasticity under stress for longer periods.
Good Formability: Better than high-hardness stainless steel, though not quite as good as brass.

Disadvantages:

Highest Cost:Typically the most expensive among common materials.
Lower Conductivity than Brass: E-field SE slightly lower than brass.
Poor Magnetic Shielding:Non-magnetic.
Best For: Critical components needing a combination of high strength, superior elasticity/spring properties, good conductivity, and corrosion resistance. E.g., high-performance spring contacts, battery contacts, frequently removed shields. Common in high-end connectors, precision electromechanical components, medical devices.

Advantages:

Excellent Electrical Conductivity:Provides very high Electric Field (E-field) shielding effectiveness, especially at high frequencies.
Good Corrosion Resistance: Suitable especially for non-harsh indoor environments.
Excellent Formability: Easy to stamp, bend, deep draw. Low work hardening rate means longer die life, ideal for complex shapes.
Good Solderability: Often solderable without special plating.
Aesthetic: Natural gold color sometimes used for visible components.

Disadvantages:
Higher Cost: Raw material cost usually higher than stainless steel.
Lower Strength:Less robust than stainless steel; larger cans or those needing support may require thicker material or ribs.
Poor Magnetic Shielding: Non-magnetic, offers weak low-frequency magnetic field (H-field) shielding.
Risk of Stress Corrosion Cracking (SCC): Can crack under stress in specific environments (e.g., containing ammonia).
Best For: Applications needing extremely high high-frequency SE, complex geometries, easy soldering; where magnetic shielding is less critical. Common in high-frequency communication modules, RF circuits, precision instruments.

Pre-Plated Materials: Base materials (e.g., steel) pre-plated with nickel, tin, silver, etc., to improve solderability, corrosion resistance, or appearance. Simplifies your secondary plating process.

Aluminum: Lightweight, good conductivity, but poor formability (usually cast or machined, not stamped), difficult to solder. Less common for stamped shields.

Laminated/Composite Materials: E.g., steel/copper/steel sandwiches attempting to combine steel strength with copper conductivity. High cost, complex processing, limited use.

Conductive Gaskets/Elastomers: While not the can material itself, often used with metal cans at seams. Gasket material choice (silicone backing + metal/conductive particle filler) must also be compatible with the can material.