Tool Path Optimization Of Five-axis CNC Machine Tool

Five-axis CNC machine tools are the key equipment in modern advancedmanufacturing technology. Five-axis CNC machine tools are often used for the finishingof complex surface parts and large-scale precision molds.Five-axis tool location file is generally represented by the small segments whichare composed by tool center points and the vectors of tool axis. However, apart from thelarge data of small segments, the velocity and acceleration would have the situation ofdiscontinuity between several pieces of segments. And it will also cause vibration forthe machine and affect the processing efficiency and quality. So this thesis focus on theissue of five-axis machining trajectory optimization.Five axis trajectory is composed by the tool center point and the vector of tool axis.This thesis proposed bi-cubic spline interpolation optimization method for well qualitymachining trajectory in contralateral side milling or milling finish machining, and usethe cubic spline interpolation method for the track of tool center points and the track ofvectors of tool axis. In the process of interpolation, this thesis according the determiningarea which can used the spline interpolation, first proposed sub-regional approach basedon the shape error and curvature distinguish from the open-loop method which are onlybased on segment length, changing rate of segment length and the size of the visualangle. Thus we achieve the closed loop optimization controlled by spline fitting. Duringthe process of bi-cubic spline interpolation, it will be inconsistency at break because theinterpolation is simultaneously between upper and lower curves. The thesis presentsdata fusion method, and making two divisions in the curve is consistent to ensure theaccuracy of spline interpolation.Meanwhile, according to the situation that the vectors of tool axes change greatwhich cause the movements of five axes are uneven and the machining efficiency isreducing in the process of end milling rough machining, this thesis proposed theoptimization methods for changing the tool center point and making the vectors of toolaxes change smoothly.At last，the machining experiment was carried out on the five-axis machine tool.We use the codes before optimization and the codes after optimization to processimpeller separately. We obtain a good effect，and verify the method in the paper.