JPS55162435A - Powder molding method - Google Patents

Abstract

PURPOSE:To produce the glass powder molding of accurate shape by putting glass powder into the recess constituted by a center die and lower punch, and molding the same by an upper punch, then moving upward both upper and lower punches while pressing and holding the glass powder molding thence moving upward only the upper punch. CONSTITUTION:The mixture 1 comprising making the glass of 150 mesh or less added with about 4% of organic binder such as polyethylene glycol to grain sizes of 300-100mu by a spray dryer is packed in the spacing 4 formed by a center die 2 and lower punch 3. Next, an upper punch 5 is lowered to compression-mold the mixture under pressing pressures of 100-300kg/cm<2>, whereby a glass powder molding 6 is made. In this state, the upper and lower punches are moved upward simultaneously, thence only the upper punch 5 is moved upward to take out the molding 6. At the time when the upper punch is moved upward, the compression stress in the molding 6 by the center die 2 has disappeared and therefore the production of a missing part 6a in the top surface of the molding owing to deposition of glass powder 1a on the bottom surface of the upper punch 5 does not occur and the molding of always accurate shape may be obtained.