| 摘要 |
PROBLEM TO BE SOLVED: To provide an injection molding method which can produce a high-accuracy large metal powder molding with high productivity without surface defects, e.g. wrinkles or welds.SOLUTION: A method of producing a large metal powder injection molding comprises mixing and kneading a raw material powder consisting of a metal powder or an alloy powder with a binder prepared by blending a wax ingredient and/or a lubricity imparting ingredient, a plastic ingredient and a plant oil in a blend ratio within an appropriate range to obtain a compound, using a die which allows heating or cooling of the cavity surface, heating, with a heating medium, the cavity surface of the die to a temperature equal to or higher than the load deflection temperature and equal to or lower than the thermal decomposition temperature of the plastic ingredient of the binder blended with the compound, injecting the plasticized compound into the cavity to form a molding, cooling the cavity surface to a temperature lower than the load deflection temperature of the plastic ingredient of the binder by using a cooling medium to solidify the compound and taking out the molding. |
