| 摘要 |
<P>PROBLEM TO BE SOLVED: To provide a method for manufacturing a screw point, which enables efficient manufacture and attains reduction in cost. <P>SOLUTION: In a method for manufacturing a screw point 10 including a screw with four ridges having a shape similar to a twisted quadrangular pyramid, a heated material is subjected to hot casting to form a screw using an upper die 16 and a lower die 18 set by a vertically zigzag parting line 20 including a crest line 22 which is defined by an edge line of crests of respective discontinuously appearing ridges and a trough line 24 crossing trough portions of the respective ridges, the parting line 20 being alternately sequentially continued corresponding to an outline of the screw point 10 to be formed in a planar view. <P>COPYRIGHT: (C)2013,JPO&INPIT |
