| 摘要 |
PROBLEM TO BE SOLVED: To mold a golf ball having a uniform cover thickness without causing a filling failure by providing a gate in a position where the maximum flow length flowing along a cavity circumferential wall of a molding material injected through the gate never exceeds a specified value. SOLUTION: In a golf ball injection molding mold 1 having a spherical cavity 2 in the inner part and a plurality of molding material injection gates 5 opened to the cavity, the gates 5 are provided in positions where the maximum flow length flowing along the circumferential wall of the cavity 2 of the molding material injected through the gates 5 never exceeds√3πr/4 (r represents the radius of the cavity 2). The maximum flow length not exceeding√3πr/4 means that the length from the gates 5 to the converging position never exceeds√3/8 of the circumference of the spherical cavity 2, which is rather short, compared with in the past. When it exceeds this, the molding material is reduced in flowability or solidified before filling, causing a filling failure near the converging position. |
