Abstract: Disclosed are systems and methods that permit both real-time, and off-line, measurement of weld penetration depth. Exemplary systems and methods comprise an ultrasound source, such as a pulsed Nd:Yag laser, that simultaneously generates longitudinal and shear waves that radiate adjacent one side of a weld joining two specimens. An ultrasonic sensor, such as an electro-magnetic acoustic transducer or a piezo-electric transducer, capable of detecting shear and/or longitudinal waves, is disposed on an opposite side of the weld from the source. A signal processor is coupled to the sensor that processes time of flight signals for selected longitudinal or shear waves transmitted across the weld seam. The signal processor implements an algorithm that computes the weld penetration depth from the time of flight signals.

Abstract: A method and apparatus for measuring thermally induced warpage in test elements such as printed wiring boards and printed wiring assemblies, including a heating chamber having a transparent window and support structure for supporting a printing wiring board in an observation orientation and position parallel to the transparent window. A glass grating placed adjacent the window and a light source shines through the window onto the printed wiring board under test. A camera is positioned for capturing images of shadow moire fringes formed over time as the oven heats up the printed wiring board or printed wiring assembly to simulate actual process conditions. A computer is used for controlling operation of the apparatus and for evaluating the captured images of the moire fringes in relation to the temperature as a function of time.