Development of On-Machine Measurement System Utilizing Line Laser Displacement Sensor

2011 ◽  
Vol 5 (5) ◽  
pp. 708-714 ◽  
Author(s):  
Go Abe ◽  
◽  
Masatoshi Aritoshi ◽  
Tomoki Tomita ◽  
Keiichi Shirase ◽  
...  
Keyword(s):  
Machine Tool ◽  
Precision Measurement ◽  
Error Compensation ◽  
Point Method ◽  
Displacement Sensor ◽  
Precision Machining ◽  
Laser Displacement Sensor ◽  
Cnc Machine ◽  
Machining Error ◽  
Measurement Device

Demand for precision machining of dies and molds with complex shapes has been increasing. Though high performance CNC machine tools are widely utilized for precision machining, machining error compensation is still necessary to meet accuracy requirements. For precision measurement, a workpiece must usually be unloaded from a CNC machine tool. Then, the workpiece is measured by a precision measurement device, such as 3D CMM. After the machining error is clarified according to the measurements taken, the workpiece must be re-clamped for the necessary error compensation machining. This error compensation machining is costly and time consuming, and it requires a highly skilled machinists. The re-clamping of the workpiece also causes positioning errors. Therefore, demands for on-machinemeasurement have been increasing. In this paper, an on-machine measurement device that consists of a line laser displacement sensor is developed. This measurement device, attached to the spindle head of a machine tool with magnetic clamps, has special features, such as noncontact, multi-point, high-speed measurement capabilities. Additionally, a sequential multi-point method, an extension of the two-point method, is applied for shape measurement accuracy.

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.

Straightness Error Compensation for Ultra-Precision Machining Based on a Straightness Gauge

2008 ◽  
Vol 381-382 ◽  
pp. 105-108 ◽  
Author(s):  
Guo Hui Cao ◽  
Yoshiharu Namba
Keyword(s):  
Machine Tool ◽  
Error Compensation ◽  
Surface Profile ◽  
Displacement Sensor ◽  
Precision Machining ◽  
The Real ◽  
Nano Scale ◽  
Nc Program ◽  
Ultra Precision ◽  
Straightness Error

A method of straightness error compensation is presented, which is used in ultra-precision machining with nano-scale accuracy for a large mandrel manufacture. A set of measurement system in situ is developed, in which an ultra-smooth glass-ceramic flatness gauge and a non-contact micro displacement sensor with nano-scale resolution were used as a reference and sensor to get the straightness error of machine tool movement. The real straightness error can be obtained after subtracting the surface profile of the gauge from the original straightness error curve. Based on the real straightness error data, a new NC program was made for compensating the error from the axis movement of machine tool. As a result, after straightness error compensation, the straightness errors of two axes of ultra-precision machine tool are 68nm/400mm and 54nm/300mm respectively.

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.

Volumetric Error Modeling and Analysis for CNC Machine Tool Based on Multi-Body System

2010 ◽  
Vol 426-427 ◽  
pp. 441-446 ◽  
Author(s):  
Zhen Ya He ◽  
Jian Zhong Fu ◽  
Xin Hua Yao
Keyword(s):  
Error Compensation ◽  
Measurement Method ◽  
Precision Machining ◽  
Cnc Machine Tool ◽  
Body System ◽  
Software Platform ◽  
Cnc Machine ◽  
Vector Measurement ◽  
Measurement And Analysis ◽  
Multi Body

With the development of the CNC precision machining and the ultra-precision machining, machine tools error issue has became the most active research topics and concerned by more and more experts. In this paper, a rapid simulation software platform based on multi-body system theory and Matlab software for measurement and analysis geometric errors of CNC machine tool is presented, which includes the generation of simulated measurement data, data processing, error separation and error compensation etc. To verify the feasibility of the developed software, the sequential step diagonal vector measurement method has been analyzed. The experimental results show that after error compensation the machine performance is improved by 39%. It demonstrates that the sequential step diagonal vector measurement method could significantly improve the machine accuracy and the developed software platform is reliable. This platform is not only effective for step diagonal vector measurement method, but also can be applied to other measurements. Therefore, the software platform provides a fast, reliable and objective tool for machine error measurement and analysis.

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