Molding process and device therefor
AssigneeSumitomo Metal Industries, Ltd.
InventorsKiyoshi Sudani, Yoshihiko Sunami
Life of this patent
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Abstract
A molding process of a molding compound containing an ingredient such as a binder, e.g., pitch or a thermosetting resin which generate gas before being set, is disclosed, wherein the molding compound is heated and molded under pressure according to a special temperature pattern. First, the molding compound may be preheated substantially uniformly to a temperature at which the binder melts and generates reaction gas. Next, temperature gradient in the direction of thickness of the molding is created while raising the temperature of the molding to an upper limit temperature so that the setting of the molding progressively advances from the higher temperature to the lower temperature side of the molding.
Claims16
A method of molding a molding compound which contains pitch, wherein the pitch, when heated, melts with evolving gas and then sets or solidifies at a higher temperature, comprising the steps of:
- putting the molding compound into a mold;
- heating the molding compound under pressure at a temperature sufficient to cause the setting of the pitch wherein the molding compound is subject to a compressive force along a direction and the compound is heated on each of two ends which lie along the direction of the compressive force, whereby a temperature gradient is created along the direction of the compressive force, thereby progressively advancing the setting of said molding compound from one end of the molding compound which is at a higher temperature to the opposite end which is at a lower temperature;
- cooling the molding compound after the molding compound has been set;
- and
- removing the resulting molding from the mold.
A method as claimed in claim 13, wherein said higher surface temperature is in the range of from 500.degree. to 550.degree. C.
A molding device for molding a molding compound comprising:
- a mold frame having a bore extending therethrough, said mold frame being made of an iron alloy having a linear expansion coefficient ranging from 0 to 1.2.times.10.sup.-6 /C.degree.;
- upper and lower punches slidably inserted in said bore of the mold frame;
- means for pressing said upper and lower punches against a molding compound poured into a space in the bore limited by said upper and lower punches;
- and
- means for heating said upper and lower punches, said means for heating comprising means for separately heating said upper and lower punches.
Dependencies are inferred from the claim text.