Research of On-Line Monitoring Technology of Machining Accuracy of CNC Machine Tools

2013 ◽  
Vol 846-847 ◽  
pp. 268-273
Author(s):  
Rong Bo Shi ◽  
Zhi Ping Guo ◽  
Zhi Yong Song

This paper analyzes CNC machine tools machining error sources, put forward a kind of on-line monitoring technology of CNC machine tools machining accuracy based on online neural network. Through the establishment of CNC machine tools condition monitoring platform, collection sensor signal of the key components of CNC machine tools, using time domain and frequency domain method of the original signal processing, extract the characteristic related to machining accuracy change, input to the neural network, identification the changes of machining accuracy. The experimental results show that, the on-line monitoring technology based on neural network, can identify the changes of machining accuracy.

2014 ◽  
Vol 635-637 ◽  
pp. 407-410
Author(s):  
Shuang Yong Wang ◽  
Wei Zhang ◽  
Qian Wei Zhang ◽  
Jian Hua Yang ◽  
Peng Fei Zhang

As a core feature of high-end CNC machine tools, the torque carrying performance of five-axis milling head directly affects the machining accuracy and reliability. Through theoretical analysis and derivation, combining experimental prototype, the A/C-axis cutting torque formula of five-axis milling head on woodworking is obtained. The reliability analysis provides a theoretical basis for drive motor selection and five-axis milling head structural optimization and improvement.


2018 ◽  
Vol 2018 ◽  
pp. 1-16 ◽  
Author(s):  
Cong Geng ◽  
Yuhou Wu ◽  
Jian Qiu

Since a nonlinear relationship exists between the position coordinates of the rotation axes and components of the tool orientation, the tool will deviate from the required plane, resulting in nonlinear errors and deterioration of machining accuracy. Few attempts have been made to obtain a general formula and common rules for nonlinear error because of the existence of various kinematic structures of machine tools with orthogonal configuration. This paper analyzes the relationship between the deviation of cutter location points and motion of tool orientations. Five-axis CNC machine tools are divided into two groups according to the configuration of the two rotational joints and the home position. Motions of the tool are regarded as a combination of translation and rotation. A model for error calculation is then built. The maximum deviation of the tool with respect to the reference plane generated by the initial and the final orientation is used to quantify the magnitude of the errors. General formulas are derived and common change rules are analyzed. Finally, machining experiment is conducted to validate the theoretical analysis. The research has important implications on the selection of a particular kinematic configuration that may achieve higher accuracy for a specific machining task.


2021 ◽  
Vol 23 (3) ◽  
pp. 559-568
Author(s):  
Zhiming Wang ◽  
Hao Yuan

The purpose of this paper is to propose a general precision allocation method to improve machining performance of CNC machine tools based on certain design requirements. A comprehensive error model of machine tools is established by using the differential motion relation of coordinate frames. Based on the comprehensive error model, a reliability model is established by updating the primary reliability with an advanced importance sampling method, which is used to predict the machining accuracy reliability of machine tools. Besides, to identify and optimize geometric error parameters which have a great influence on machining accuracy reliability of machine tools, the sensitivity analysis of machining accuracy is carried out by improved first-order second-moment method. Taking a large CNC gantry guide rail grinder as an example, the optimization results show that the method is effective and can realize reliability optimization of machining accuracy.


2014 ◽  
Vol 2014 ◽  
pp. 1-11 ◽  
Author(s):  
Shao-Hsien Chen ◽  
Wern-Dare Jehng ◽  
Yen-Sheng Chen

This paper mainly covers a research intended to improve the circular accuracy of CNC machine tools and the adjustment and analysis of the main controller parameters applied to improve accuracy. In this study, controller analysis software was used to detect the adjustment status of the servo parameters of the feed axis. According to the FANUC parameter manual, the parameter address, frequency, response measurements, and the one-fourth corner acceleration and deceleration measurements of the machine tools were adjusted. The experimental design (DOE) was adopted in this study for taking circular measurements and engaging in the planning and selection of important parameter data. The Minitab R15 software was adopted to predict the experimental data analysis, while the seminormal probability map, Plato, and analysis of variance (ANOVA) were adopted to determine the impacts of the significant parameter factors and the interactions among them. Additionally, based on the response surface map and contour plot, the optimal values were obtained. In addition, comparison and verification were conducted through the Taguchi method, regression analysis to improved machining accuracy and efficiency. The unadjusted error was 7.8 μm; through the regression analysis method, the error was 5.8 μm and through the Taguchi analysis method, the error was 6.4 μm.


2014 ◽  
Vol 682 ◽  
pp. 192-195 ◽  
Author(s):  
U.S. Putilova ◽  
Yu.I. Nekrasov ◽  
A.A. Lasukov

To improve the treatment accuracy by on-line correction of the paths of the executive working parts (EWP) the authors study the processes of loading, deformation and arrangement deviation of the elements of the manufacturing systems (MS) under the changes of the cutting force components in the process of turning on machine-tools equipped with CNC systems of PCNC class. Estimation of the values of the technological components of the cutting force Px, Py, Pz is based on the phenomenon of arrangement deviation Δωi of the elements monitoring the servo drives of machine tools. To determine the compliance of the deviation magnitude Δwi with the technological components of the cutting force Px, Py a diagnostic subsystem was developed, involving the loading devices and dynamometric equipment. The diagnostic system is controlled through PCNC with the application of a specially developed hardware-software system. The data on changes in the values Px, Py and the respective changes in the attitude misalignment parameters in servo drives at various EWP minute feeds in CNC machine tools were determined by prior diagnosis of load characteristics servo drives, registered in the PCNC. So, the data of cutting force components Px, Py compliance with arrangement error ratios ΔωXп, ΔωZп. were established.


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