| 摘要 |
PROBLEM TO BE SOLVED: To improve productivity and yield of a screw for osteosynthesis and to enable to drastically improve drawing strength of screw threads. SOLUTION: A molding 1 formed of in vivo degradable and absorptive resin into a cylinder is inserted into a small diameter tear part 11 at fire and fixed by a stopper 13, then a first swaging punch 5 is actuated to press the tip end of the molding 1 and cooled and pulled out after a prescribed time, and further second and third swaging punches 6, 7 are actuated to form the screw head part. Next, a heated metal mold is pressed from four directions to press the metal mold from directions orthonal to the axis, cooled after a prescribed time, and released to form thread grooves on the molding 1. Further, preferably the molding 1 is rotated in 45 deg. and pressed again to remove flashes produced by the first pressing. |
