Robots make radios (1940s style)

    The innovative Electronic Circuit Making Equipment (ECME) process and the radio design were fully protected by patents. Using the ECME process it was possible to form on a pre-moulded bakelite panel most of the passive electronic components required in a radio receiver, such as capacitors, inductances, resistors and potentiometer tracks. Sargrove was in this way working towards the concept of the microchip, though in the chip the ‘component’ layers are in a solid ‘block’ with no mounting material.

    John Sargrove announced the details of the ECME automatic production system to a meeting of the British Institution of Radio Engineers on 20 February 1947. The meeting was reported in ‘The Times’ the following day and caused great interest throughout the industry.

    Sargrove’s 1947 paper described the electronic structure of the sprayed-circuit panels in great detail. The last section described the manufacturing process by the ECME machines.

    By 1947 the dream had become reality. Sargrove Electronics Ltd designed and built the ECME machines - standing for Electronic Circuit Making Equipment. ECME could automatically produce complete radio circuit panels, ready for final assembly, at the rate of three every minute.

    The idea was to reduce manual labour in manufacturing radio sets to a minimum and eliminate errors in wiring. This was done by making the the wiring and components an integral part of a pre-moulded panel. Completed panels only required a few components such as valves to be inserted by hand before the completed assembly was fitted into the set’s cabinet. All the ECME operator had to do was feed in the pre-moulded bakelite panels. As the panels passed through, they were grit-blasted, sprayed with metal and graphite, milled, lacquered and tested, emerging twenty seconds later ready for final assembly on the bench.

    After spraying with metal the panels passed into the face-milling unit. High-speed diamond tools removed metal from the upper surfaces, leaving it in the grooves and depressions. A second spraying followed, this time with a resistive material such as graphite. The various eyelets, valve bases, potentiometer arms and other components needed were then pressed in automatically. The panel was sprayed with lacquer, and finally the circuits were tested.

    After emerging from ECME the circuit boards were fitted with valves and loudspeaker by hand. Then the completed assembly was fitted into the moulded cabinet.