The helicoidal surfaces are produced mostly by form cutting with forming cutters of end mill type , side mill type or disc type .
螺旋面大多数是用球头铣刀、侧铣刀、盘形刀具成形加工出来的。
Vibration of helicoidal structures widely applied in engineering is studied . A numerical analysis method for free vibration characteristics of elastic helicoidal structures with a great twist is presented .
