Synthesis and Analysis Problems of Profiling the Tool for Grinding Helical Surfaces

Abstract

Modern machines with software control have the ability to create an arbitrary specified profile in the axial section of the grinding wheel. Therefore, by carrying out the calculation of the radial cross-section of the grinding wheel by using mathematical methods, it is possible to obtain a tool to grind a helical surface with the required accuracy. With each dressing of the grinding tool, taking into account the change in the tool diameter, the profile will need to be recalculated, which will not lead to loss of accuracy. In this paper the methods for synthesis and analysis of profiling of a grinding wheel for processing various types of cylindrical helical surfaces with the required accuracy are presented. The solution of the synthesis problem is described for the external thread of the most general type. To construct the lateral surface of the grinding wheel, a stationary in space curve of the tangency of the lateral surface of the circle and the surface of the screw thread is determined. The axial section of the tool is defined in a tabular form. The shape of the surface of the thread is obtained on the basis of the wrapping model as a result of mathematical simulation of the blank machining by the grinding wheel of the earlier defined shape. The part of the blank removed during machining is considered as the union of the intersection areas of the tool and the blank in their various relative positions. The helical surface is defined in tabular form. Since obtaining even a theoretically absolutely accurate surface is not always possible, calculation of the processing error along the normal to the thread surface is performed. The proposed methods are implemented in the form of program modules. An example of using the described techniques for machining a buttress external thread is given. The described methods are used at the machine-tool plant of JSC "MSZ-Salut" when grinding on the MSh520 machine.