With the new electro-magnetic method, it is said, castings can be produced at the rate of 200 or more per minute with minimum wear of parts and stoppage of machinery for repairs. Since various parts of aeroplanes and engines are cast, the new electro-magnetic method would thus speed production of these defence materials.
In prior methods of die casting, it is explained, the molten metal was forced into the mould by pistons or compressed air, The pistons had a tendency to jam, while with compressed air difficulty was met in withdrawing air from the mould prior to the next charge. In the new method the mould has a cavity into which the nozzle of a tube or conduit discharges molten metal. The other end of the tube dips into the mólten metal pot. The metal rises in the tube td the level of that in the pot.
Surrounding the tube is a wire coi] which is attached to an electric circuit. When the switch is thrown into one circuit, current flows through the coil, setting up electro-magnetic forces. These forces pull the molten metal up the tube and force it out the nozzle into the mould. When the mould is filled, the switch is thrown into another circuit which reverses the current, setting up en electro-magnetic force that draws the metal away from the nozzle. The switch can be controlled so that the flow of metal into the mould by electro-magnetic forces is automatically regulated.
Text read from the printed page and cleaned; old type leaves the occasional error.