Why It’s Different 

In a percussion weld the joint is made of the two parts and nothing else. No filler metal, no solder and no flux is added, so there is nothing to select, apply or clean off, and no second material in the joint that can change how it behaves.

The process also has no electrodes to wear out and no consumables to purchase. That keeps material waste down, and it is why the same weld can be repeated part after part with only the parameters to manage.

This is the first thing to separate percussion welding from crimping and soldering: it makes a metallic bond between the parts themselves.

Percussion welding heats only the surfaces that are being joined. An electrical arc melts them, they are thrust together while molten, and the bond forms within milliseconds. The heating time is short enough that little heat spreads into the surrounding metal.

That is why the heat-affected zone (HAZ) is minimal, with little or no negative effect on the materials. It allows welding on small components, fine wires and heat-sensitive assemblies where the area around the joint has to stay unchanged.

The melting-gap diagram on this page shows the idea. To see how far heat spreads for different metals and heating times, use the HAZ calculator.

Many pairs of metals are difficult to join because they melt at different temperatures or do not alloy well. Percussion welding melts only the faying surfaces for a moment and forges them together, so two different metals can be joined directly, with no third metal between them.

Our lab weld-schedule database holds 131 schedules across 33 materials and 68 material pairs, from copper to stainless steel to tungsten to nickel. Check your pair in the material compatibility checker, get starting parameters in the Parameter Finder, or read the full guide to dissimilar metal welding.

If your pair is not in the data, we say so and offer a test instead of guessing.

Because the weld is made without filler or solder, there is no foreign material between the two parts to add resistance. The result is a joint with low electrical resistance, which matters for leads, terminals, thermocouples, sensors and battery connections where the weld is part of the circuit.

We do not quote a resistance value for percussion welds in general. It depends on the metals, the cross-section and the parameters, so measure it on your own parts and tell us the requirement.

Repeatability comes from controlling the few things that matter and being able to check each weld. The system is built around three products:

• Model 858 Percussion Welder: the power supply and controller. Actuator speed, delay and weld energy are set on dials, with switches for mode, pulse, polarity and capacitance, so a working setting can be written down and set again.
• Model 726 Bench Fixture: holds the wire and the workpiece, with adjustment for position and gap, so the pre-defined gap is the same every time.
• Percussion Weld Monitor: an optional tool that learns a signature waveform from good welds and compares each later weld with it, with a Pass/Fail result.

See the 858, the 726 and the Percussion Weld Monitor for details.

Percussion welds resist shock and vibration. In pull tests the wire often breaks before the weld, which shows the weld held while the wire itself gave way.

We show these tests on the bench rather than describe them: the videos on this page include pull tests of copper wire welded to stainless steel and of copper-clad steel wire. Results depend on materials and parameters, so we recommend validating joint strength on your own parts before production, changing one setting at a time as you tune.

Percussion welding is for small parts: fine wires, leads, pins and thin sections, in medical device, automotive, electronics, aerospace and defense work and in batteries, thermocouples, heater elements and lighting. It is not the answer to every joint, and we will tell you plainly when it is not.

The fastest way to know is to see your parts welded. Free applications tests of your materials are available, and we can run live, in-person tests at our lab in Denver. Bring your most challenging current project, or send the materials, and we will show you what the process does with them.