Tool path analysis and improving contouring accuracy in large-size crankshaft grinding on a lathe

In this paper, we addressed a method for improving the contouring error of grinding crankshaft pins by the tangential point tracing machining method on a large lathe, which is not a special crankshaft grinding machine tool. The main problems are tool path analysis, configuration of servo systems, and automatic control. Traditional cylindrical grinders are used in crankshaft grinding, but we have selected the bowl-type grinder as a grinding tool and analyzed the tool path, and then synchronization error between the spindle and the tool feed axis of the lathe is modeled. Based on this model, cross-coupling control and iterative learning control are applied to reduce the contouring error in crankshaft grinding. To verify the effectiveness of the proposed method, simulations with MATLAB/SIMULINK and field experiments are carried out. The simulation and experimental results showed that the high precision crankshaft can be machined at low cost on conventional lathes, even though it is not a special crankshaft machining equipment.