Suitable Materials for Ultrasonic Metal Spot Welding

1. Ideal Materials for Consistent, Reliable Welds (Industry Standard)

Pure Copper Grades

T1/T2 oxygen-free copper, copper foil, copper strips, multi-strand copper wiring, copper terminals and busbarsTypical uses: wiring harness joints, battery copper tabs, motor leads, power bus connections

Pure Aluminum Grades

1060 / 3003 / 5052 aluminum foil, aluminum strips, battery aluminum tabs, aluminum busbars, thin aluminum alloy sheetsTypical uses: lithium battery tabs, new energy busbars, aluminum wiring, heat sink assemblies

Nickel Materials

Solid nickel strips, nickel-clad steel strips, battery nickel tabs and nickel sheet connectorsBenefits: Robust weld strength with minimal brittling; standard material for battery production

Plated Composite Metal Strips

Nickel-plated copper, nickel-plated steel, tin-plated copper, silver-plated copper sheetsThin plating layers do not disrupt ultrasonic bonding; no prior plating removal required

2. Workable Materials (Requires Tuned Welding Parameters)

1. Gold & silver: Thin precious metal foils for electrical contacts (use low amplitude and low clamping pressure)

2. Brass, phosphor bronze, beryllium copper: Spring terminals and electrical connectors. Medium vibration amplitude recommended; surfaces must be cleaned to remove oxidation.

3. Thin stainless steelOnly compatible with ultra-thin stainless steel foil (≤0.15 mm). Thick stainless steel is overly hard and thermally conductive, making consistent welding impractical.

4. Thin galvanized steel: Acceptable with thin zinc coatings; heavy zinc plating causes slag buildup and weak joints.

3. Dissimilar Metal Pairings (Key Advantage Over Resistance Welding)

Copper to aluminum, copper to nickel, aluminum to nickel, copper to nickel-plated steel, aluminum to thin stainless steel foil, silver to copperBenefits: This is a room-temperature solid-state joining process with no molten metal. It avoids brittle intermetallic layers and retains excellent electrical and thermal conductivity, making it ubiquitous for lithium batteries and wiring harnesses.

4. Unsuitable Materials (Not Recommended for Welding)

1. Plain iron, thick stainless steel, carbon steelHigh hardness and low ductility prevent proper plastic deformation from ultrasonic vibration. Resulting joints are fragile, prone to sparking and excessive heat buildup.

2. High-hardness alloys: Thick titanium alloy plate, tungsten, molybdenum, chromium alloys

3. Parts with heavy oxidation or stubborn oil residue that cannot be fully cleanedOxide films block molecular fusion, producing low-strength, unreliable welds.

4. Non-metallic substrates: Plastics, rubber, ceramics (these require dedicated ultrasonic plastic welders)

5. Thick metal combinations with drastically different melting points

6. Components coated with thick insulating lacquer, heavy scale or unremoved anti-rust grease

Compatible Part Configurations

• Stacked multi-layer thin foils (copper / aluminum foil stacks)

• Multi-strand wire harness splicing

• Lap joints between thin foils and thick terminals

• Battery tabs, flexible bus links, laminated power connection sheets

Quick Overview

Ultrasonic metal spot welders deliver optimal results on copper, aluminum, nickel and dissimilar joints between these metals. Thin plated metals can also be welded with adjusted settings. Thick iron, heavy-gauge stainless steel and hard alloys are not viable candidates.