scholarly journals Identification, development and testing of thermal error compensation model for a headstock assembly of CNC turning centre

2014 ◽  
Vol 3 (2) ◽  
pp. 113 ◽  
Author(s):  
Ramesh Babu ◽  
V.Prabhu Raja ◽  
J. Kanchana ◽  
Devara Venkata Krishna
Keyword(s):  
Machine Tool ◽  
Analysis Of Variance ◽  
Error Compensation ◽  
Machine Tools ◽  
Thermal Error ◽  
Error Model ◽  
Transient Temperature ◽  
Cnc Machine ◽  
Grey Correlation ◽  
Thermal Error Model

In CNC machine tools, transient temperature variation in the headstock assembly is the major contributors for spindle thermal error. The compensation of thermal error is critical for ensuring the accuracy of machine tool. The performance of an error compensation system depends largely on the accuracy and robustness of the thermal error model. In the present work, a robust thermal error model is developed for minimizing the error in lateral direction of the spindle which significantly influences the geometrical accuracy of the workpiece. Analysis-of-variance (ANOVA) is applied to the results of the experiments in determining the percentage contribution of each individual temperature key point against a stated level of confidence. Based on the analysis of existing approaches for thermal error modeling of machine tools, an approach of LASSO (least absolute shrinkage and selection operator) is proposed in order to avoid the multi collinearity problem. The proposed method is an innovative variable selection method to remove redundant or unimportant temperature key points in the linear thermal error model and minimize the residual sum of squares. The predictive error model is found to have better robustness and accuracy in comparison to the combination of grey correlation and step wise linear regression for error compensation of CNC lathe. Keywords: Analysis Of Variance (ANOVA), CNC Machine Tool, Grey Correlation Analysis (GCA), Headstock Assembly, LASSO Regression, Mean Absolute Deviation (MAD), Mean Square Error (MSE), Robustness, Standard Deviation (SD), Thermal Error.

scholarly journals Thermal Error Compensation of Spindle System of Computer Numerically Controlled Machine Tools Through Experiments and Modeling

2020 ◽  
Vol 19 (4) ◽  
pp. 301-309
Author(s):  
Jianchen Wang ◽  
Tao Jiang ◽  
Junquan Shen ◽  
Junhao Dai ◽  
Zequan Pan ◽  
...  
Keyword(s):  
Machine Tool ◽  
Error Compensation ◽  
Machine Tools ◽  
Thermal Error ◽  
Local Optimum ◽  
Cnc Machine ◽  
Machining Error ◽  
Generalization Ability ◽  
Computer Numerically Controlled ◽  
Thermal Error Compensation

This paper attempts to solve the insufficient machining precision of computer numerically controlled (CNC) machine tools, which is induced by the thermal error of the spindle. Firstly, the relationship between machining error and thermal sensitive points was analyzed through experiments. On this basis, the backpropagation neural network (BPNN) was improved by particle swarm optimization (PSO). Next, the improved network (PSO-BPNN) was used to build a thermal error compensation (TCE) model for the spindle of machine tools. Taking VM-500T precision machine tool as the object, the temperature data were grouped through the optimization based on thermal imaging, grey relational analysis (GRA), and fuzzy clustering, to determine the temperature sensitive items that causes the thermal error. To speed up network convergence, the PSO algorithm was introduced to optimize the number of hidden layers and the number of hidden layer nodes of the BPNN, lifting the network from the local optimum trap. To enhance the generalization ability, the weights and thresholds of the BPNN were also improved by the PSO. After that, two TCE models were established for the spindle of the machine tool, respectively based on the original BPNN and PSO-BPNN. Contrastive experiments show that the PSO-BPNN TCE model achieved the better generalization ability, and improved the prediction accuracy of the machining error of the CNC machine tool.

A Combined Error Model for Thermal Error Compensation of Machine Tools

2013 ◽  
Vol 820 ◽  
pp. 147-150 ◽  
Author(s):  
Wei Wang ◽  
Jian Guo Yang
Keyword(s):  
Error Compensation ◽  
Machine Tools ◽  
Thermal Error ◽  
Industrial Applications ◽  
Error Model ◽  
Cnc Machine ◽  
Different Temperatures ◽  
Experimental Validations ◽  
Compensation Approach ◽  
Thermal Error Compensation

In this paper, a combined error model for thermal error compensation of machine tools is presented. Through the analysis of thermal error data of machine spindle at different temperatures, the error variation law is obtained. Experiments on the axial directional spindle deformation on a CNC machine center are conducted to build and validate the proposed models. The experimental validations show that the thermal errors of the machine tool are reduced effectively after applying the error compensation approach. The combined error model performs better than the traditional time series and neural network model in terms of prediction accuracy and robustness, which means that the new model is more suitable for complex working conditions in industrial applications.

Precision Enhancement of Ucp710 5-Axis Machine Tool by Real Time Thermal Error Compensation

2008 ◽  
Vol 375-376 ◽  
pp. 539-543 ◽  
Author(s):  
Xiu Shan Wang ◽  
Jin Hua Shen ◽  
Jian Guo Yang
Keyword(s):  
Machine Tool ◽  
Error Compensation ◽  
Thermal Error ◽  
Temperature Fields ◽  
Cnc Machine Tools ◽  
Cnc Machine ◽  
Sensing Systems ◽  
Thermal Error Model ◽  
Thermal Error Compensation ◽  
Very High

The thermal error model of the ucp710 5-axis machine tool was acquired by the homogeneous coordinate transformation, and includes 17 thermal error components. The thermal behavior of the ucp710 machine tool has been tested and the temperature fields were recorded by the compensation control and temperature sensing systems. The developed compensation system has been applied to the ucp710 5-axis machine tool, and the accuracy has been improved about 1 times after compensation, demonstrating a very high potential for the error compensation of CNC machine tools.

Application of Ubiquitous Sensor Network in Collection and Analysis of CNC Machine Tool Processing Status Information

2010 ◽  
Vol 455 ◽  
pp. 621-624
Author(s):  
X. Li ◽  
Y.Y. Yu
Keyword(s):  
Machine Tool ◽  
Sensor Network ◽  
Machine Tools ◽  
Thermal Error ◽  
Development Trend ◽  
Cnc Machine Tools ◽  
Cnc Machine Tool ◽  
Cnc Machine ◽  
Status Information ◽  
The Development Trend

Because of the practical requirement of real-time collection and analysis of CNC machine tool processing status information, we discuss the necessity and feasibility of applying ubiquitous sensor network(USN) in CNC machine tools by analyzing the characteristics of ubiquitous sensor network and the development trend of CNC machine tools, and application of machine tool thermal error compensation based on USN is presented.

Analysis on the Thermal Error Compensation Model of Direct-Drive A/C Bi-Rotary Milling Head

2011 ◽  
Vol 87 ◽  
pp. 59-62
Author(s):  
Peng Zheng ◽  
Xin Bao ◽  
Fang Cui
Keyword(s):  
Machine Tool ◽  
Error Compensation ◽  
Thermal Deformation ◽  
Thermal Error ◽  
Direct Drive ◽  
Cnc Machine ◽  
Compensation Model ◽  
Axis Rotation ◽  
Thermal Error Compensation ◽  
Deformation Error

The thermal deformation error that is the biggest error of effecting the machining precision of Direct-drive A/C Bi-rotary Milling Head was narrated in brief. Based on the introduce of the study status on the thermal error compensation techniques of CNC Machine tool, the momentum of thermal deformation of Bi-rotary Milling Head was analyzed. According to the Trigonometric Relations in A/C axis rotation angle of Bi-rotary Milling Head and the momentum of thermal deformation in Bi-rotary Milling Head and -axis respectively, a thermal error compensation model was established to make the Machine tool to compensate for thermal errors in -axis.

A Review of Geometric Error Modeling and Error Detection for CNC Machine Tool

2013 ◽  
Vol 303-306 ◽  
pp. 627-631 ◽  
Author(s):  
Zhen Yu Han ◽  
Hong Yu Jin ◽  
Yu Long Liu ◽  
Hong Ya Fu
Keyword(s):  
Machine Tool ◽  
Error Detection ◽  
Error Compensation ◽  
Machine Tools ◽  
Performance Criterion ◽  
Geometric Error ◽  
Error Modeling ◽  
Cnc Machine Tool ◽  
Cnc Machine ◽  
Error Sources

Error compensation can improve the accuracy of machine tools effectively. Among the error sources affecting the accuracy of CNC machine tool, geometric error is always set as a key performance criterion. This paper summarizes several methods of geometric error modeling and reviews the characteristics of different methods. Furthermore, available methods for measuring geometric errors have been reviewed also based on the advanced instruments. This work aims at enhancing the efficiency of error detection and give a perspective for the application of error compensation in the future.

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