Method for modifying plunge shaving cutters

Abstract

A method for modifying plunge shaving cutters aims to modify a plunge shaving cutter through a grinding tool. The plunge shaving cutter has a plurality of helical teeth spaced from each other. The helical teeth have a machining-intended side. The method of modification includes the steps of: positioning the plunge shaving cutter on a gear forming grinder with the machining-intended side in contact with the grinding tool; moving the plunge shaving cutter according to a variable rotation amount and a first variable movement amount; moving the grinding tool according to a second variable movement amount to perform a helical movement against the plunge shaving cutter and a modification process on the machining-intended side. Thus the existing gear forming grinder can be applied to the plunge shaving cutter for machining to improve machining speed.

What is claimed is: 
     
         1 . A method for modifying plunge shaving cutters through a gear forming grinder which includes a tool stand and a workpiece stand movable against the tool stand along a first axis, the tool stand including a machining spindle for driving a grinding tool to spin, the workpiece stand including a workpiece spindle rotating about the first axis, the method comprising the steps of:
 providing a plunge shaving cutter which includes a plurality of helical teeth spaced from each other;   defining a machining-intended side of the helical teeth;   positioning the plunge shaving cutter on the workpiece spindle to make the machining-intended side in contact with the grinding tool; and   spinning the grinding tool and rotating the plunge shaving cutter about the first axis according to a variable rotation amount and moving the plunge shaving cutter along the first axis according to a first variable movement amount, and moving the grinding tool along a second axis perpendicular to the first axis and the machining spindle according to a second variable movement amount such that the grinding tool moves helically against the plunge shaving cutter to perform a modification process on the machining-intended side;   wherein during the modification process a ratio of the variable rotation amount and the first variable movement amount is a first variable obtained through calculation of a tooth profile parameter of the plunge shaving cutter, and a ratio of the second variable movement amount and the first variable movement amount is a second variable obtained through calculation of the tooth profile parameter.   
     
     
         2 . The method of  claim 1 , wherein the tooth profile parameter includes a cutting-intended thickness on the machining-intended side. 
     
     
         3 . The method of  claim 2 , wherein the machining-intended side includes a plurality of cutting blades spaced from each other along the first axis, each of the plurality of cutting blades being formed at an unmodified thickness gradually decreasing inward from an outer side before the modification process is performed. 
     
     
         4 . The method of  claim 3 , wherein the machining-intended side includes a plurality of cutting blades spaced from each other along the first axis, each of the plurality of cutting blades being formed at a modified thickness by subtracting the cutting-intended thickness from the unmodified thickness that gradually decreases inward from the outer side after the modification process is finished. 
     
     
         5 . The method of  claim 1 , wherein the machining spindle spins about a third axis perpendicular to the first axis, the tool stand further including an upright movement portion coupled with the machining spindle to move the machining spindle along the third axis. 
     
     
         6 . The method of  claim 5 , wherein the tool stand further includes a swing portion coupled with the upright movement portion to swing the upright movement portion about the second axis. 
     
     
         7 . The method of  claim 6 , wherein the tool stand further includes a horizontal movement portion coupled with the swing portion to move the swing portion along the second axis.