Vision for Process Control

Machine vision requires parts to be placed in a known location and orientation, and careful control of lighting. It is also less tolerant of part variations, which can be a benefit if variations indicate defects. To its credit, machine vision can make hundreds of precise measures per second and, once installed, provides inexpensive and reliable labor. Most machine vision systems have components for part positioning, lighting, image forming (lens), one or more cameras, a vision processor and an interface to process and motion control. Some engineers also use part-in-place sensors, such as a photosensor, to signal when a part is ready for inspection. For example, in an application where a manufacturer needed to determine the dimension of stamped metal parts made by a progressive punch press, the manufacturer had been measuring sample parts off line, so die wear or damage was not detected until thousands of bad parts had been produced. Replacing that off-line manual system with a vision system made by system integrator Faber Industrial Technologies that inspects each part and stops production when the part dimensions show that a die is worn or damaged. The result was improved quality, less scrap and higher productivity.