Automatic high-speed measuring systems for complex products and shapes: interdependent computation and cybernetic inspection machinery

A high-speed self-adaptive system of inspection is described and the reasons for evolving it are explained. Sequential measurement on a transfer-line is used to measure complex-shaped parts reliably to effective accuracies between ± 1 to 2 microns. Each measured dimension is stored up in analogue memory devices and later read-out as the object reaches the sorting or pass/reject gates. The decision to pass or reject the object is carried out in a self-adaptive logic system in which the subsidiary dimensions are compared with the dominant dimensions and the upper and lower tolerance limits of the subsidiary dimensions are automatically shifted instantaneously for each object as the dominant dimension varies within tolerance, thus achieving critical inspection for true shape. Machines are described for measuring conical and spirally grooved complex shaped objects such as twist-drills in more than one place. Also measurements of more abstract factors are referred to, such as inspection at speeds of 180 measurements per minute involving computing for `density¿ and pass/reject action on this factor. Practical results have been obtained in machines which have inspected millions of objects. The cost of such apparatus is justified by reduction of scrap and manual inspection labour in production of precision parts