Method and device for detecting the mechanical forces at the welding pin tip during friction stir welding

A friction stir welding device for detecting mechanical forces during friction stir welding, the friction stir welding device comprising:

• a) a tool bell comprising a tool receptacle conus and a welding pin having a pin shaft and pin tip, wherein the welding pin is connected to the tool bell by a welding shoe;
• b) a strip-shaped sensor attached to a longitudinal, external side of the tool bell, wherein the strip-shaped sensor is configured for determining force, pressure, or path;
• c) a sensor positioned in a tailored conus feature in the tool receptacle conus, wherein the sensor is configured for determining an axial force, a torque, and a bending moment at the welding pin;
• d) at least three sensors distributed at a spacing of 120 degrees around a circumference of the tool receptacle conus;
• e) a piezoelectric force-measuring sensor located along a longitudinal axis of the pin shaft;
• f) a sensor signal amplifier comprising a rotary antenna for receiving, for amplifying, and for transmitting all detected measured values measured by the sensor, wherein the measured values are transmitted by a static antenna to a machine controller;
• g) an inductive power supply system comprising a moving secondary coil and a stationary primary coil, wherein both coils are positioned within the tool bell.