Testing dimensional accuracy of components - involves using projector in whose light cone opaque components are placed

摘要

Component shadows are compared with a standard drawing. Light sensitive diodes are provided at points on the shadow edge (A) to be measured; when dimension are correct, diodes are partly illuminated; signals are stored as nominal values in a first store; output signals obtained during component testing are compared with the stored values, and also signals from opposite points are compared with each other, and if necessary adjusted to each other; if measured signals differ beyond a certain tolerance, a fault signal is delivered and/or the component is rejected. The projector produces a cone of light so that the shadow of the component may be bigger than the component itself.