In the mirror milling of thin-walled parts, the machining path and the change of the tool axis vector will affect the surface quality of the workpiece and the machining efficiency. The machined surface was discretized into point cloud data, and the surface was fitted. Based on the constraints of mirror milling, the tool location points, and machining paths were generated first. Then the tool location points in the space were projected onto the parameter plane to fit the spline curve. What's more, the position of the corresponding point on the fitting surface was obtained from the tool position point after fitting on the parameter plane and obtaining the tool axis vector. After obtaining the optimized tool position data, the tool axis vector was optimized based on kinematic constraints, precisely, the machine tool rotation axis needs to satisfy the constraints of the maximum angular velocity, maximum angular acceleration, and maximum angular jerk. Therefore, in the process of machining, due to the problems of angular velocity, angular acceleration, and angular jerk at certain tool positions exceeding the limit, feedrate for CNC machines was optimized first. Furthermore, the optimization target was established based on the minimum sum of the motion fluctuations of the rotary axis and the machining time. After that, the optimized machining path and tool axis vector were simulated and tested. Finally, the simulation and experimental results were determined through analysis, which proved the feasibility of the optimized model proposed in this paper. At the same time, the experimental measurement results also showed that the optimized machining path had been significantly improved in both quality and efficiency.

Honeycomb composites (HCs) are diversely employed in aerospace, national defense and other fields owing to their remarkable spatial geometry and excellent mechanical properties. Their complex hexagonal cell structure and heterogeneous material properties cause major problems when implementing high-quality processing. Surface defects generated by processing will reduce the capability and service lifespan of the honeycomb sandwich structure. Therefore, the high quality of HCs is a topic of close attention for researchers. In this paper, the consequences of different cutting parameters of rotary ultrasonic machining (RUM) on surface quality with an ultrasonic circular knife (UCK) were studied through multiple groups of single-factor and orthogonal experiments with two-factors/four-levels and one-factor/three-levels. The single factor experiment was used to explain the effect that the degree of cutting parameters has on surface quality, and the orthogonal experiments were applied to explain the interaction between the processing parameters and the influence law of each factor on surface quality. Therefore, the reasonable cutting parameters of HCs were determined through experimental results to provide guidance for the realization of the precise and efficient machining of HCs. This study can provide a basis for the subsequent comprehensive consideration of various factors to achieve high-quality machining of HCs.

No abstract

In the mirror milling of thin-walled parts, the machining path and the change of the tool axis vector will affect the surface quality of the workpiece and the machining efficiency. The machined surface was discretized into point cloud data, and the surface was fitted. Based on the constraints of mirror milling, the tool location points, and machining paths were generated first. Then the tool location points in the space were projected onto the parameter plane to fit the spline curve. What’s more, the position of the corresponding point on the fitting surface was obtained from the tool position point after fitting on the parameter plane and obtaining the tool axis vector. After obtaining the optimized tool position data, the tool axis vector was optimized based on kinematic constraints, precisely, the machine tool rotation axis needs to satisfy the constraints of the maximum angular velocity, maximum angular acceleration, and maximum angular jerk. Therefore, in the process of machining, due to the problems of angular velocity, angular acceleration, and angular jerk at certain tool positions exceeding the limit, feedrate for CNC machines was optimized first. Furthermore, the optimization target was established based on the minimum sum of the motion fluctuations of the rotary axis and the machining time. After that, the optimized machining path and tool axis vector were simulated and tested. Finally, the simulation and experimental results were determined through analysis, which proved the feasibility of the optimized model proposed in this paper. At the same time, the experimental measurement results also showed that the optimized machining path had been significantly improved in both quality and efficiency.