An electronics job shop was building an assembly consisting of a plastic faceplate, an LCD window and a circuit board. The sandwich was held together by fifteen plastic pins that were heated and mushroomed. The LCD window is electrically connected to the circuit board by two rubber ‘zebra’ strips, which required significant clamping pressure to work reliably. B. Dash Fabrication designed and built this thermal staking press to do the job.
An operator assembles the components into an aluminum tray machined to support the faceplate at the zebra strips and pin locations.
Two toggle switches activate the automatic sequence. Four pneumatic cylinders lower an aluminum press plate, machined to clamp the sandwich at the critical points, with 2,200 pounds of force. Then a pneumatic cylinder lowers a third plate containing fifteen independent heating elements mounted in Teflon® bushings. A timer lets the heaters melt the pins down for a set time, and then raises the heater plate. A second timer takes over allowing the pins to cool and set before releasing the pressure from the sandwich.
The sequence is controlled by electronic timers operating electrical air valves. There is a panic button which will instantly raise the press and heater.