A Laser System for Detecting Surface Flaws of a Molding

An optical system for detecting the surface flaws of a molding, e.g., the brake disc of a car, has been proposed which involves a sheet-like laser beam of length, l, and width, w, as a probing light. Optimum conditions for the sheet like laser beam were found to be l=10 mm and w=0.5 mm for a flaw diameter of 2 mm which is the smallest diameter that can be detected in practice. The system consists of a sensor head including a light source and a light receiver, and a display. This system can detect all flaws in a few second by using a sampling frequency of data acquisition at 1 kHz