The development of quartz crystal production

摘要

In the inter-war period, 1918????????1939, the quartz crystal evolved from being a material of academic interest to being the source of a vital component for both wartime and peacetime radiocommunication. This paper outlines some of the problems experienced in turning the United Kingdom quartz industry over from an annual production capacity of a few thousand quartz crystal vibrators in 1938, to nearly two million in 1945. By development of machine processes, production changed from skilled hand-working to semi-skilled bulk production and was accompanied by increasingly stringent testing so as to provide a much improved final product. Some details are given of the automatic and other machine processes, of the way in which the serious activity-ageing problem of the piezo-electric element was solved, of the peculiarities of the production problem in respect of raw-material faults, and of the performance specified for the finished component. Quantities of redundant crystal units accumulated from early production and units on redundant frequencies were recovered and re-processed with a consequent saving in raw material. New types of crystal units and future developments are touched on and it is concluded that fewer crystal units, of improved types, will be required in future, to maintain a radio network of better performance and of capacity similar to that used in the late war.