Die and method of manufacturing cast product

Abstract

According to one embodiment, a biscuit section, a product section in which a cast product is to be cast, and an overflow section which is provided on the opposite side of the biscuit section with respect to the product section are provided between a stationary die and a movable die of a die. The die includes a die surface provided with a concave section in which a rib of the cast product is to be cast. The concave section includes an inner peripheral surface of the concave section which includes a first surface spreading perpendicularly to a direction from the biscuit section toward the overflow section, and positioned on the overflow section side of the inner peripheral surface, and a second surface spreading in the direction from the biscuit section toward the overflow section. Surface roughness of the first surface is finer than surface roughness of the second surface.

1 . A die for die casting comprising:
 a stationary die; and   a movable die to be combined with the stationary die, wherein   in a state where the movable die is combined with the stationary die, (i) a biscuit section into which molten metal is to be injected, (ii) a product section in which a cast product is to be cast, and (iii) an overflow section which is provided on the opposite side of the biscuit section with respect to the product section are provided between the stationary die and the movable die,   the die comprises a die surface provided with a concave section in which a rib of the cast product is to be cast,   the concave section comprises an inner peripheral surface which comprises a first surface spreading perpendicularly to a direction from the biscuit section toward the overflow section, and positioned on the overflow section side of the inner peripheral surface, and a second surface spreading in the direction from the biscuit section toward the overflow section, and   surface roughness of the first surface is finer than surface roughness of the second surface.   
   
   
       2 . The die of  claim 1 , wherein
 the inner peripheral surface of the concave section comprises a third surface spreading perpendicularly to the direction from the biscuit section toward the overflow section, and positioned on the biscuit section side of the inner peripheral surfacer and   the surface roughness of the first surface is finer than surface roughness of the third surface.   
   
   
       3 . The die of  claim 1 , wherein
 the concave section comprises a first section, and a second section formed deeper than the first section,   the second section comprises an inner peripheral surface which comprises a downstream side surface spreading perpendicularly to the direction from the is biscuit section toward the overflow section, and positioned on the overflow section side of the inner peripheral surface of the second section,   the first section comprises an inner peripheral surface which comprises a downstream side surface spreading perpendicularly to the direction from the biscuit section toward the overflow section, and positioned on the overflow section side of the inner peripheral surface of the first section, and   surface roughness of the downstream side surface of the second section is finer than surface roughness of the downstream side surface of the first section.   
   
   
       4 . The die of  claim 1 , wherein
 the die surface is provided with a second concave section in which a second rib of the cast product is to be cast, the second concave section is formed deeper than the first concave section,   the second concave section comprises an inner peripheral surface which comprises a downstream side surface spreading perpendicularly to the direction from the biscuit section toward the overflow section, and positioned on the overflow section side of the inner peripheral surface of the second concave section,   the first concave section comprises an inner peripheral surface which comprises a downstream side surface spreading perpendicularly to the direction from the biscuit section toward the overflow section, and positioned on the overflow section side of the inner peripheral surface of the first concave section, and   surface roughness of the downstream side surface of the second concave section is finer than surface roughness of the downstream side surface of the first concave section.   
   
   
       5 . The die of  claim 1 , wherein
 the concave section comprises a first section, and a second section formed deeper than the first section, the first section and the second section each comprise an inner peripheral surface, and   surface roughness of the inner peripheral surface of the second section is finer than surface roughness of the inner peripheral surface of the first section.   
   
   
       6 . The die of  claim 1 , wherein
 the die surface is provided with a second concave section in which a second rib of the cast product is to be cast, the second concave section is formed deeper than the first concave section, the first concave section and the second concave section each comprise an inner peripheral surface, and   surface roughness of the inner peripheral surface of the second concave section is finer than surface roughness of the inner peripheral surface of the first concave section.   
   
   
       7 . A die for die casting comprising:
 a stationary die; and   a movable die to be combined with the stationary die, wherein   in a state where the movable die is combined with the stationary die, (i) a biscuit section into which molten metal is to be injected, (ii) a product section in which a cast product is to be cast, and (iii) an overflow section which is provided on the opposite side of the biscuit section with respect to the product section are provided between the stationary die and the movable die,   the die comprises a die surface provided with a concave section in which a rib of the cast product is to be cast, the concave section comprises a first section, and a second section formed deeper than the first section, the first section and the second section each comprise an inner peripheral surface, and   surface roughness of the inner peripheral surface of the second section is finer than surface roughness of the inner peripheral surface of the first section.   
   
   
       8 . A method of manufacturing a cast product by die casting comprising:
 preparing a die comprising a stationary die, and a movable die to be combined with the stationary die, wherein in a state where the movable die is combined with the stationary die, (i) a biscuit section into which molten metal is to be injected, (ii) a product section in which a cast product is to be cast, and (iii) an overflow section which is provided on the opposite side of the biscuit section with respect to the product section are provided between the stationary die and the movable die, the die comprising a die surface provided with a concave section in which a rib of the cast product is to be cast, the concave section comprising an inner peripheral surface which comprises a first surface spreading perpendicularly to a direction from the biscuit section toward the overflow section, and positioned on the overflow section side of the inner peripheral surface, and a second surface spreading in the direction from the biscuit section toward the overflow section, and surface roughness of the first surface being finer than surface roughness of the second surface;   combining the movable die with the stationary die; and   injecting molten metal into the biscuit section.