Determining the Optimal Position of the Frontal-cylindrical Milling Tool in Finishing in the New Technology for Processing Worms

Helical surfaces of the worms flanks can be of two types: ruled and non-ruled. Using a new technology for processing on NC machines, cylindrical worms type ZA of various modules can be processed, using the frontal-cylindrical milling tools of different diameters, the optimal position of the mill being different in each individual case. In this article, on the basis of contact between the surface of frontal-cylindrical milling tools used in processing and a helical surface, is determined the optimal position of the mill so that deviations from the nominal profile of the worm type ZA are minimal. Determination of contact between the frontal- cylindrical milling tool and helical surface is done using coordinate transformations. The points thus obtained shall be brought in the axial plane which is compared with the points belonging to the nominal profile of the Archimedian worm. The method used is a numerical one. To get the optimal value of the angle of inclination of the cutter and eccentricity was conceived a program that verifies the smallest deviation for eccentricity variation within the range [3,3] mm and for variation of the angle of tilt of the tool towards the perpendicular to the axis of symmetry of the worm in the interval [-1.5°, 1.5°] angle value of pressure of the flank. The program is designed in AutoLISP, the resulting calculated deviations are returned in a TXT file of type where the optimal adjustment of the frontal-cylindrical milling tools is specified.