Abstract: Tightening of a bolt is controlled by monitoring the change in round trip time of propagating longitudinal ultrasonic waves through the bolt and the reflection of these waves at the end of the bolt. The round trip time of the longitudinal waves through bolt is continuously measured and monitored in real-time. Elongation of the bolt as it is being tightened is determined based on the change in the round trip time of the longitudinal waves, which provides the level of bolt tension and joint clamp load. In determining the bolt elongation, an elongation-dependent wave speed has been formulated and used in-real time. When the elongation of the bolt reaches a predetermined level, tightening is automatically stopped.

Abstract: A resistance spot welding monitoring system includes a plurality of sensors coupled to a resistance spot welding system to receive welding data produced during a welding operation. The monitoring system further includes a nugget prediction system. The welding data is indicative of welding parameters used to produce the weld nugget. The nugget prediction system retrieves the welding data and predicts a nugget size based upon the welding data received from the plurality of sensors. Additionally, the nugget prediction system generates a nugget size signal. The monitoring system also includes an indicator that receives the nugget size signal and notifies an operator of a predicted nugget size.

Abstract: A method and system for controlling a welding system collects material thickness data and material type data for a plurality of materials to be welded. A non-linear power profile is generated having a discrete stepped approximation of power over a period of time based on the material thickness data and the material type data to produce a desired current amount at a specific time during welding of the plurality of materials.

Abstract: A method for estimating weld nugget diameter includes receiving current and voltage inputs, a time input, and a force input. In certain embodiments, the method also uses other weld parameters including type of material, type of stack, stack thickness, applied force, preheat current, RMS value of weld current, weld level, and weld time. The method further determines a resistance curve based on the current and voltage inputs, and time input. It also derives parameters from the resistance curve, and determines a weld nugget diameter estimate based on both resistance parameters.

Abstract: A method for estimating weld nugget diameter includes receiving current and voltage inputs, a time input, and a force input. In certain embodiments, the method also uses other weld parameters including type of material, type of stack, stack thickness, applied force, preheat current, RMS value of weld current, weld level, and weld time. The method further determines a resistance curve based on the current and voltage inputs, and time input. It also derives parameters from the resistance curve, and determines a weld nugget diameter estimate based on both resistance parameters.

Abstract: Tightening of a bolt is controlled by monitoring the change in round trip time of propagating longitudinal ultrasonic waves through the bolt and the reflection of these waves at the end of the bolt. The round trip time of the longitudinal waves through bolt is continuously measured and monitored in real-time. Elongation of the bolt as it is being tightened is determined based on the change in the round trip time of the longitudinal waves, which provides the level of bolt tension and joint clamp load. In determining the bolt elongation, an elongation-dependent wave speed has been formulated and used in-real time. When the elongation of the bolt reaches a predetermined level, tightening is automatically stopped.