| 摘要 |
PURPOSE:To enable the manufacture of a coil so designed that the cross-sectional area at each of the portions of the coil can be set as desired, and the coil has a functional pitch which is extremely uniform in the center and gently increases toward each end, by effecting electric discharge machining while rotating a hollow cylindrical pipe about its axis and moving a wire electrode and the pipe relative to each other along the axis of the pipe. CONSTITUTION:After a hollow cylindrical pipe 1' has been set on a chuck 5, the distal end of a guide arm 7 is slightly inserted into the pipe 1' from one end thereof, and a wire electrode 6 is passed through a terminal bore 2A provided in the pipe 17 in advance and stretched between guide rollers 9 and 10. While a machining liquid such as water is being supplied to the machining gap, voltage pulses are applied between the wire electrode 6 and the pipe 1' to start machining. The machining is progressed while controlling the rate of rotation of the chuck 5 and the feed rate of the chuck 5 along the axis of the pipe 1' at a predetermined ratio on the basis of a command from a numerical controller. |
