. Transactions. eneral principles. Thismachine is used to a large extent at the present time, throughout theUnited States, for the production of zinc, tin, and lead alloy die castings. In the machine shown in Fig. 3, patented by Doehler in 1910, com-pressed air is used for forcing the metal into the die. In Fig. 4 is shownanother of this type of machine. Here compressed aii is applied to thesurface of the molten metal to force it into the die. In a machine patented by Chandler in 1914, shown in Fig. 5, the * Chief chemist, Doehler Die Casting Co. VOL. LX.—37. 578 DIE CASTINGS AND THEIR APPLICA
. Transactions. eneral principles. Thismachine is used to a large extent at the present time, throughout theUnited States, for the production of zinc, tin, and lead alloy die castings. In the machine shown in Fig. 3, patented by Doehler in 1910, com-pressed air is used for forcing the metal into the die. In Fig. 4 is shownanother of this type of machine. Here compressed aii is applied to thesurface of the molten metal to force it into the die. In a machine patented by Chandler in 1914, shown in Fig. 5, the * Chief chemist, Doehler Die Casting Co. VOL. LX.—37. 578 DIE CASTINGS AND THEIR APPLICATION TO THE WAR PROGRAM principle of the internal-combustion engine is applied for exerting pressureon the molten metal. A charge of gasoline vapor and air is injected intothe melting chamber, the explosion of which forces the metal into the writer has never heard of this machine being used on a commercialbasis, but it is mentioned to show the various means suggested for forcingmolten metal into a Fig. 1.—Underwood die-casting machine. Methods Used to Avoid Blow-holes The fact that die castings are made under pressure would suggest,on first thought, dense and homogeneous castings; this impression, how-ever, is not in accord with actual practice. On fracture, the pressure diecasting will be found to consist of a dense closely grained outer stratumand a porous inner stratum. Blow-holes of varying size may be expectedin the center of the die casting, particularly- through heavy machines have been designed with the primary object of over-coming this difficulty and producing solid die castings. Fig. 6 shows an air-operated die-casting machine with the die inclosedin a vacuum chamber. The inventor evidently assumed that the onlycause for blow-holes in the casting was the presence of air in the Fig. 7 is shown another die-casting machine in which the vacuumprinciple is applied; here the vacuum is applied directly to the die. The production of die
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Keywords: ., bo, bookcentury1800, bookdecade1870, booksubjectmineralindustries
