US 2006/0076321 A1 · Ultrasonic in-process monitoring and feedback of resistance spot weld quality

Abstract

A method and apparatus for ultrasonic in-process monitoring and feedback of resistance spot weld quality uses at least one transducer located in the electrode assembly transmitting through a weld tip into an underway weld. Analysis of the spectrum of ultrasonic waves provides the operator with an indication of the size, thickness, location, dynamics of formation and quality of the spot weld. The method presents a fundamentally new physical approach to the characterization of the spot weld quality. Together with transmission mode it includes new modes of operation of ultrasonic probes such as a reflection mode and simultaneous use of transmission and reflection modes, and a new physical interpretation of the signal analysis results.

Claims32

Dependent claims

An apparatus for monitoring welding in a resistance welder, the resistance welder including first and second electrodes, the apparatus comprising

an ultrasonic probe disposed within the first electrode that generates a burst of acoustic energy that is directed to a weld subject, receives acoustic energy reflected from the weld subject and generates an output signal in response to the reflected acoustic energy;
and
a computer that receives the output signal, the computer determining a characteristic of a liquid zone that forms during welding based on a phase inverted acoustic wave reflected from an interface between the liquid zone and a solid portion of the weld subject proximal to the ultrasonic probe;
the liquid zone solidifying into a weld nugget after welding current is turned off

1 more element

In a resistance welder having a first electrode and a second electrode, a method of monitoring welding of a weld subject with the resistance welder, comprising:

a. generating bursts of acoustic energy with an ultrasonic probe disposed in the first electrode;
b. generating an output signal with the ultrasonic probe in response to acoustic energy reflected from the weld subject;
c. determining based on the output signal whether the reflected acoustic energy includes a phase inverted acoustic wave reflected from an interface between a liquid zone and a solid portion of the weld subject proximal to the ultrasonic probe;
and
determining a characteristic of the liquid zone based on the phase inverted acoustic wave, the liquid zone solidifying into a weld nugget after welding current is turned off.

2 more elements

Dependencies are inferred from the claim text.

Ultrasonic in-process monitoring and feedback of resistance spot weld quality

Life of this patent

Ultrasonic in-process monitoring and feedback of resistance spot weld quality

Life of this patent

Abstract

Claims32