Tool Path Calculation Of Machining On Sculptural Surface Based On Grinding Wheel Enveloping Profile

Complex surfaces are widely used in machinery, petroleum, chemical, aerospace and other fields. The requirement for its accuracy is increasing. The sculptural surface CNC grinding is an important means of finishing, but all current programming is based on the ideal grinding wheel profile. Manufacturing errors and wear of wheel is a great impact on machining precision, and it has relatively high expectations for the precision of wheel dressing. In the paper, instead of the ideal profile, it's used to calculate tool path. This is a new concept of precision machining complex surfaces, which reduce the requirements of precision of grinding wheel when it enveloping grinds the sculptural surface.In this paper, the concept of the grinding wheel enveloping profile is put forward: the grinding wheel rotates around its own axis and grinds a hypothetical sample plate without thickness. Achieved shape is defined as the grinding wheel enveloping profile, which covers the grinding wheel size and shape errors, and grinding spindle turning error. It's the actual profile in the enveloping grinding process. Firstly, it is studied mathematical principles and implement methods for getting the grinding wheel enveloping profile curve and building 3-dimensional model of the grinding wheel. Secondly, tool path of NC machining on sculptural surface is calculated based on grinding wheel enveloping profile by minimal orientation-distance algorithm. Finally, this method is proved to be feasible by simulation and error analysis. This paper also programmed for the mathematical principles and basic algorithms associated with the example calculation and formed the corresponding blocks. It laid the foundation for programming CAM software for CNC grinding complex surface based on grinding wheel enveloping profile in the future.As can be seen from the simulation, compared with programming based on the ideal grinding wheel profile, this method can improve the machining precision effectively, while reduce the requirements of precision of grinding wheel when it envelop grinding the sculptural surface. After the grinding wheel wearing out, we can re-measure its enveloping profile and recalculate the tool path. This saves time, thus improving the processing efficiency. Especially for the CBN and diamond grinding wheel whose profile retention are better, this method can greatly reduce the difficulty of modification and the times of modification and improve the machining accuracy and efficiency.