| 摘要 |
A cylindrical surface (3) is roughed to be prepared for a spray film (11) to be formed thereon, by cutting therein rough undulations (21) in a threaded form, using a cut chip (20) leaving a groove part (21a) of a respective undulation (21) in a preset direction or cut form, for breaking or partially tearing off a ridge part (21b) of the rough undulation (21) to have a remainder of the ridge part (21b) formed with finer undulations (22). |
