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AssigneeNippon Piston Ring Co., Ltd.
InventorTadashi Ebihara
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A powder compression molding method for producing a multilayer powder compression molded article having a plurality of different material layers disposed in a compression direction utilizes relative movements between an upper punch, a lower punch, a die having a step formed therein, and two feed shoes. The powder compression molded article thus formed requires a reduced amount of a special layer. The powder compression molding method includes forming a first space by moving the die relative to the lower punch, introducing a first powder into the first space through a first feed shoe, lowering the lower punch relative to the die to form a second space so that an upper surface of the first powder on the step of the die and on the lower punch has a nonuniform height, introducing a second powder into the second space, and moving the upper punch towards the lower punch to compress the first and second powders.
A powder compression molding method for producing a multi-layer powder compression molded article having a plurality of different material layers disposed in a compression direction by utilizing relative movements of an upper punch, a lower punch, a die, and first and second feed shoes, the method comprising the steps of:
A powder compression molding method for producing a multi-layer powder compression molded article having a plurality of different material layers disposed in a compression direction by utilizing relative movements of an upper punch, a lower punch, a die, a core rod, and first and second shoes, the method comprising the steps of:
A powder compression molded article comprising a first and a second layer, the first and second layers comprising different materials, a boundary between the different material layers having a rest-curve like shape formed by relative movement between a punch and a die after said first layer in powder form is deposited on an upper surface of said punch and said die but prior to said second layer in powder form being deposited on said first powder layer.
Dependencies are inferred from the claim text.