Metal Stamping Welding and Assembly Guide

Short answer: stamped parts often need welding, riveting, clinching, or threaded fasteners as secondary operations to become finished assemblies. Common stamped-part welding methods include resistance projection welding, laser welding, MIG/TIG, and stud welding. Joint design, material compatibility, plating, and heat-affected zone control determine the right method.

This guide is for design engineers and sourcing teams who buy stamped parts that will be welded into assemblies. Understanding how stamping geometry, material, and surface finish affect weld quality helps avoid costly rework and strength failures.

Send your assembly drawing and weld specifications through the RFQ form. For related assembly topics, see stamped metal assemblies and secondary operations and metal stamping plating and passivation guide.

Resistance projection welding

The most common method for stamped assemblies. A projection (embossed dimple, ridge, or ring) is coined into one stamped part. Current passes through the projection, which collapses under pressure, creating a fused nugget. Advantages:

• No filler material needed
• Fast cycle time (0.5-3 seconds per weld)
• Consistent nugget size when projection geometry is controlled
• Can weld multiple points simultaneously
• Suitable for low-carbon steel, stainless, galvanized, and aluminum with proper electrode tuning

Design recommendations for weldable stamped parts

• Projection geometry: dimple diameter 2-4 mm, height 0.3-0.8 mm for 1-2 mm material
• Material thickness ratio: ideally 1:1 to 3:1 between joined parts
• Plating: zinc plating above 8-12 microns can cause weld expulsion; consider selective plating or weld-before-plating sequence
• Edge distance: projection center should be at least 2x material thickness from any edge
• Material compatibility: weld low-carbon to low-carbon, stainless to stainless; avoid welding stainless to galvanized steel
• Burr direction: parts should be stacked with burr facing inward to avoid interference with weld interface

Laser welding for precision stamped assemblies

Laser welding is used for hermetic seals, small components, and assemblies where minimal heat input is critical. Typical applications:

• Battery contact plates and busbar assemblies
• Medical device stamped components requiring clean welds
• Sensor housings and electronic shields
• Thin foil or shim stacks (0.1-0.5 mm per layer)

Fastener insertion for stamped assemblies

Many stamped parts receive self-clinching fasteners (PEM nuts, studs, standoffs) or threaded inserts for bolted connections:

• Clinching nut installation: requires hole size within 0.05 mm of spec, material hardness below HRB 80
• Weld nuts: projection or spot weld types for thicker material or post-plating assembly
• Helical inserts: for aluminum or soft stamped parts needing reusable threads
• Stake and rivet: cold forming or orbital riveting for permanent joints

Design checks before welding or assembly

Assembly problems often start in the stamping print. A flange that is too narrow, a hole placed too close to a bend, or a coating specified before welding can make a good stamped part difficult to join. Review the assembly sequence while the die design is still flexible, especially when the stamped part will be plated, passivated, powder coated, or packed as a ready-to-install subassembly.

• Weld access: leave room for electrodes, clamps, shielding gas, or laser path access. Tight return flanges may need fixture pockets.
• Flatness and coplanarity: welded brackets and shields need contact surfaces controlled before joining; see the coplanarity guide.
• Burr direction: keep burrs away from weld interfaces, sealing faces, and fastener seating surfaces.
• Finish sequence: decide whether the part is weld-before-plate, plate-before-assembly, passivate-after-weld, or locally masked.
• Fixture datums: define the surfaces used to locate the assembly during welding so dimensional inspection matches the build process.

What to include in an assembly RFQ

Send the stamped part drawings, the finished assembly drawing, material grades, thicknesses, weld callouts, finish requirements, annual volume, inspection expectations, and packaging needs. If the assembly has failed in production before, include the failure mode, such as weld pull-out, distortion, cosmetic burn marks, nut torque-out, or thread damage.

Useful companion pages include clinching and self-clinching fasteners, hardware insertion for stamped parts, stamped metal assemblies, and packaging and shipping for stamped parts.

FAQ

Submit your assembly RFQ

Send your assembly drawing, weld specifications, plating requirements, and annual volume through the RFQ form. Include the material grades, thicknesses, and plating of each component in the assembly.