Electric conductivity in the TOX-Clinch Joint

The behaviour of the electric resistance is specially important when used in electrical appliances and electric conductors nowadays used in passenger cars as prefabricated door tracks for feeding the door electrics. A most reduced transition resistance is of the advantage. Here applies: the lower the transition resistance, the higher the electric conductivity.

A further, often most important aspect, is the significantly higher dynamic strength of the cold-formed TOX-Clinch joint in comparison with spot welding, where the heat brought into the joint changes the material structure which is detrimental for the strength of the welding spot. That’s why dynamically loaded welding spots are inferior to the TOX-Round Joint with regard to joint strength.

From hitherto realized applications and comprehensive lab and field tests we gathered the following findings with regard to electric properties of the TOX joining:

• The sheet/foil surfaces pressed together and deformed under high pressure to build the TOX-joint are favourable for electric conductivity.
• Coated surfaces flow also into the joint and reduce the transition resistance. The major part of the current flows through the joint. The surrounding surface contributes only little (10 %) to the current conduction. Decisive is the joint!
• Oiled, galvanized and glued surfaces of steel sheets have only little influence on  transition resistance.
• A comparison between welding spots and Clinch joints depends on the combined materials.
• For joining smallest electronic components, the TOX-MICROpoint is the ideal solution for diam. 1 mm and larger:: cold joining of thinnest sheets with smallest flange widths, no thermal change of material, minimal distortion in the piecepart.
• Plastic foil between sheets, punctured during the joining process, flows with the material and achieves almost a tenfold increase of the transition resistance.
• The combination “steel/aluminium” shows about the same results as a “steel/steel” arrangement.