The predominant welding method used in the manufacture of car bodies is the resistance spot welding method. Hand-held and robot electrode holders as well as multispot welding machines are used. In all cases the electrode force is applied via a compressed air cylinder or electric motor. The welding current needed to form the nugget is transmitted to the metal sheet by cables/strands, electrodes or holders and welding caps. Due to the different geometric shapes and different arragementsof the parts to be joined by welding, there is a wide variety of types and sizes of current conducting elements. Standard parts, which should be used as far as possible, are standardised in DIN EN ISO 2183 (shanks) and DIN ISO 5821 (electrode caps).
The standard material for electrode caps is Elmedur X (CuCr1Zr - A 2/2) or Elmedur XS (CuCrZr - A 2/3) for higher stresses. The holders are made of Elmedur X and preferably Elmedur HA in the case of high welding forces.
To maintain the same-sized spot diameter over the tool life of the electrodes, Electrode tip dressers are now generelly used in automatic production processes as well as with hand guns.
Application
Caps, electrodes and electrode shanks according to German and international standards or to customer drawings specifications.
