Advanced Materials Research Vols. 945-949

Abstract: In dual-axis contouring motion, contouring error is a more important performance index than tracking error. Considering direct drive XY table control accuracy, the influence of load disturbance and the velocity mismatch between X and Y axis are great. As a result, the position tracking iterative learning controller based on DOB controller is adopted at single axis, it can overcome the influence of the load disturbance, and ensure the robustness of the system; For the velocity mismatch between X and Y axis, a control strategy based on hybrid error iterative learning control (HILC) and the real-time contour error model was proposed. Simulation results show that the designed control system of XY table has strong robustness, high contour accuracy and simple structure.

Abstract: The thermal error compensation and modeling is an effective way to improve the machining tool precision. This article took the CNC boring and milling center for example. Firstly, this article made analysis and research on the heat sources by analyzing the structural characteristics of CNC boring and milling center, and then on the basis of the previously measured data of selected critical temperature points, established the thermal error model using a method of multiple linear regression based on least square method. The model parameters were solved by MATLAB software. Finally, thermal error compensation model was tested.

Abstract: Aiming to deal with thermal error of NC machine tool which can cause reduce of machining accuracy, this paper uses an external error compensation which interacts with NC controllers and PMAC multi-axis and then revises the tool path by adding the error tested in real-time by PMAC card. The processing accuracy is improved eventually. This method can compensate machine geometric errors and thermal errors in real-time. Comparing with other methods of error preventing, this method is more effective and affordable.

Abstract: For the contour accuracy of direct drive X-Y servo system is susceptible to changes of the load parameters and nonlinear disturbances including the friction , A quadratic optimal position controller with sliding contour tracking controller based on equivalent errors model is proposed to improve contour tracking performance and the robustness. The position controller is designed by the factorization of quadratic optimization on frequency domain. Based on Equivalent Errors model including the equivalent contour error and tangential error, the contour tracking problem is converted to the stabilization of error dynamic system. Simulation and experimental results show that the effects of nonlinear disturbances are reduced effectively and the designed controller has high contour tracking accuracy and strong robustness.

Abstract: In order to improve the manufacturing accuracy of NC machine tool, it is crucial to reducing the temperature rise of high-speed motorized spindle. The cooling effect and temperature distribution of water-cooling system are simulated and analyzed based on thermodynamics, heat transfer theory and computational fluid dynamics in this paper. The results show that the cooling system has fine cooling effect; the temperature of cooling liquid is changed from low to high and then to decrease, the highest temperature is at the roundabout of helical water channel and the reason for this phenomenon is found out. The results provide the theory basis for the structure optimization for water-cooling system.

Abstract: The availability Research of heavy CNC Equipment is based on the equipment life cycle process from design, manufacture, production and assembly to run, involves cooperation process and information exchange timely among availability research institute, equipment manufacturers and multi-class equipment users, combine network and database techniques, build high-level platforms for information exchange and management, broaden cooperation field and ensure accuracy for original information timely. Moreover, multi-class users can complete certain task together with the help of fault information collected, equipment improvement, information-sharing and issues discussed.

Abstract: A new numerical control system (CNC) based on ARM9 and STC12C5410 is studied. The ARM9 core microprocessor and Samsung S3C2440A microprocessor, are the main operation cores. It treats the flowing tasks: response to keyboard inputting, display contents on LCD, interpretive the NC codes, output crude interpolations and so on. The secondary CPU, STC12C5410, as the assisting microprocessor is only to realize fine interpolation. The system can be connected an 8-inches display in order to display more information and it has an interface to a four-axis hand wheel. It has a communication interface and can receive CNC codes form other computer. The system can drive four step-servo motors or servo-actuators and realize turning, milling, grinding and combination machining, which making sure the system is a multifunction system.

Abstract: Post-Processing is the key of the transformation from CL-Data of CAM system to NC program. Since the improper selection of rotation angle will leads to collision between cutter tool and work piece and dramatic change of rotary axis in adjacent cutter-location as well as rotary angle changes rapidly and non-linear error exceeds allowable limits in singular area, We proposed a method which integrates optimization of rotation angle and singular handling in five-axis post-processing. A post–processor was developed with C++ program language based on the method, which inputs the CL-Data of CATIA NC manufacturing module and outputs the NC program. The validity of the method is verified through Vericut simulation.

Abstract: Based on the concept of modularity and reconfiguration, this paper adopts the function— principle—structure modeling approach, shedding light on dividing and reconstructing the modules based on the product function and finally put forward molding scheme. The author also verifies the feasibility of this kind of modeling method with the reconfigurable machine tools in turning and milling as case study.

Abstract: This paper studies control and motion theory of feed system of the five-axis CNC machine tools, propose the method of establish mathematical model, kinematics model of the feed system, in order to provide a method of theoretical research for accuracy identification of five-axis CNC machine tools.