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Technology1 min read

Ultrasonic welding instead of soldering: why we weld strands

Where several cables meet at one point, we join the strands by ultrasonic welding. The result is a compact node, without solder and without a sleeve.

ultrasonically welded strand nodes
From our production: ultrasonically welded strand nodes.

How it works

In ultrasonic welding, the bare strands are pressed between a sonotrode and an anvil and moved by high frequency vibration. The surfaces rub against each other, oxide layers break up, and the wires bond in the solid state, without the metal melting.

The advantages over soldering

  • No solder and no flux in the wiring harness
  • No stiff soldered zone that can become a breaking point under vibration
  • Compact nodes that are easy to insulate and protect
  • Copper, aluminium and mixed material joints are possible
  • Process data for every weld

We still solder wherever components or printed circuit boards call for it.

Our machine

We have been welding on a Schunk Minic-III since 2023. According to the manufacturer it handles weld cross sections from 0.26 to 30 mm², records the process data of every weld and measures the geometry of the node with a digital displacement measuring system.

The article Ultrasonic splice in the wiring harness explains how a splice is constructed and tested.