Method of welding weld studs to a workpiece

US5938945A · kind A · utility

Assignee

• Emhart Inc. · US

Inventors

• Jörg Hofmann · Krefeld, DE
• Roland Kurz · Linden, DE
• Klaus Schmitt · Wiesbaden, DE

Key dates

• Filing date: Jul 3, 1996
• Grant date: Aug 17, 1999
• Expiry date: Jul 3, 2016

Classification

• Technology area (CPC B): Performing Operations; Transporting
• CPC primary: B23K9/205
• WIPO field: Machine tools
• WIPO sector: Mechanical engineering

Abstract

The invention relates to a method of welding weld studs to a workpiece, in particular of aluminum in each case, by the stroke ignition method, in which the stroke height(s) of the weld stud (1) is altered as a function of the measured arc voltage and optionally of the arc firing time. In particular, the stroke height(s) of the stud (1) can be increased during the occurrence of short circuits, i.e. during a sudden drop in the arc voltage, preferably in predetermined steps. The weld stud is immersed into a pool of melt after a predetermined period of time of between 5 and 10 ms after the welding current has been switched off. The polarity of the stud or of the workpiece is changed at least once during the welding process. The welding current is interrupted for a predetermined period of time for this purpose. The method leads to an improved, readily reproducible quality of weld.