A Toolpath Generation Method under the Constraint of Interpolation Error in STS Precision Turning with PVT Interpolation

The complicated surface part generally possesses exceptional properties, then the developments of high-end equipment and the precision physics experiment are in pressing demand of it. To accurately manufacture the complicated surface part, this study presents a toolpath generation strategy for slow tool servo (STS) turning with position-velocity-time (PVT) interpolation under the constraint of the specified interpolation error. Based on the mathematical principle of PVT interpolation, the interpolation point is calculated. With the anticipant curve represented with a spatially circular arc, the cutter contact point (CCP) of the toolpath with PVT interpolation is derived under the constraint of the specified interpolation error by way of the presented bisection algorithm. Then the cutter location point (CLP) of the toolpath is calculated through the tool nose radius compensation for STS turning. The validated experiment shows that the workpiece machined with the toolpath with PVT interpolation generated through the proposed scheme satisfies the constraint of the specified interpolation error. The peak to valley (PV) value of the form error of the surface is 8.2 μm, besides the root mean square (RMS) value of the form error is 1.9 μm. The volume of CLPs of the toolpath is reduced by 51.7% compared with the toolpath discretized by an equal angle. The achievement of this study provides guidance for the STS precision turning with PVT interpolation for the complicated surface.