Abstract: A method is provided for detecting resonant ultra sound (RUS) Spectroscopy peaks which is based upon taking the second derivative of the RUS spectrum. The second derivative provides a more sensitive analysis tool, and makes it possible to separate and distinguish peaks in the spectrum which are not readily discernable by other analyses of the spectrum. Analysis criteria such as cut off heights and Z-widths provide judgment criteria for identification of resonant peaks.

Abstract: A method of measurement of objects by resonant ultra sound is used to determine object surface to near surface flaws. First, the frequency for expected degenerate surface acoustic wave responses is determined for one or more input frequencies and then splitting of degenerate resonant modes are observed to identify the presence of surface flaws in the object.

Abstract: A method for manufacture of printed circuit boards uses plasma etch back/desmear, carbon deposits on board surfaces to be plated and panel plating. The plated board is abrasively pre-treated, imaged, developed, etched, and stripped for final preparation before drilling. The pre-treating, imaging, developing, etch back and stripping used for inner panel boards is the same as the process steps and equipment used for the final process of the panel plated boards. The process is environmentally conscious in that it produces waste products which contain only one metal in solutions easily treated by conventional and non-conventional waste treatment technologies and eliminates or reuses by-products produced by other printed circuit board and produces waste products which contain only one metal.

Abstract: An ultrasonic measurement method for distinguishing between unflawed and flawed parts comprises the steps of detecting at least two prominent resonant response frequencies, measuring the frequency difference between the two frequencies, determining the ratio of the frequency difference to one of said frequencies, and comparing the ratio to a predetermined part criterion. Resonant response frequencies dependant upon physical characteristics such as dimensions and weight are compared to other resonances which are at frequencies dependant upon stiffness of the part.

Abstract: A method and apparatus for ultrasonic resonance testing of an object is shown and described. Acoustic vibrations are applied to an object at a plurality of frequencies. Measurements of the object's vibrational response are made simultaneously at different locations on said object. The input frequency is stepped by using small frequency changes over a predetermined range. There is a pause interval or ring delay which permits the object to reach a steady state resonance before a measurement is taken.