The invention relates to the technical field of turning methods, in particular to a method for
processing a
helical surface of a toroidal worm by a numerically controlled lathe. The method comprises the following steps of: clamping a to-be-processed worn on the numerically controlled lathe, wherein the plane where the to-be-processed worm is located is S, n and n1 are separately two instantaneous positions, generated when a toothed slot changes as the toroidal worm rotate, of a point on the side surface of a toothed slot in the axial section extending section; moving the tool
nose on the corresponding surface of a
cut-off tool to the point n, performing bootstrap program for enabling the corresponding tool
nose to move to the point n1, carrying out interpolation motion by taking R+m as a
cutting radius from the point n1,
processing out a circular-arc
helical line of one side surface, withdrawing the tool to the
initial point n, and
cutting a circular-arc
helical line of the other side surface in the similar way, thereby completing
cutting of the helical surface of the worm. A to-be-processed
initial point is determined by performing the bootstrap program, so that the position of the to-be-processed
initial point can be accurately determined, dependence on a special numerical-control
machine tool is avoided, technical requirements on an operator worker are reduced, manufacturing cost is reduced, the to-be-processed point can be found once, and
processing efficiency is greatly improved.