Mathematical model of machine-tool accuracy with account for the oscillations of its actuators

2007 ◽  
Vol 27 (7) ◽  
pp. 454-458
Author(s):  
A. A. Seregin
2014 ◽  
Vol 556-562 ◽  
pp. 1354-1357
Author(s):  
Li Gong Cui ◽  
Gui Qiang Liang ◽  
Fang Shao

This paper presents a mathematical method to analyze the influence of each machine tool part deformation on the machining accuracy. Taking a 3-axis machine tool as an example, this paper divides the machine tool into the cutting tool sub-system and workpiece sub-system. Taking the deformation of lower surface of the machine bed as the research target, the mathematical model of the deformation on the displacement of the cutting point was established. In order to distribute the stiffness of each part, the contribution degree of each part on the machining accuracy was analyzed. Using this mathematical model, the stiffness of each part can be distributed at the design stage of the machine tool, and the machining accuracy of the machine tool can be improved economically.


2014 ◽  
Vol 590 ◽  
pp. 121-125 ◽  
Author(s):  
Wen Kai Jie ◽  
Jian Chen ◽  
Deng Sheng Zheng ◽  
Gui Cheng Wang

The coupling characteristic of the tool-holder/spindle interface in high speed NC machine has significant influence on machine tool accuracy and process stability. With the example of HSK-E63, based on nonlinear finite element method (FEM), the coupling characteristic of the tool-holder/spindle interface under high rotational speed was investigated, the influence of interference, clamping force and rotational speed on the contact stress and the sectional area of clearance were discussed in detail. The results can be used as theoretical consideration to design and optimize the high speed tool-holder/spindle interface.


2019 ◽  
Vol 35 (6) ◽  
pp. 887-900 ◽  
Author(s):  
K.-Y. Li ◽  
W.-J. Luo ◽  
M.-H. Yang ◽  
X.-H. Hong ◽  
S.-J. Luo ◽  
...  

ABSTRACTIn this study, the thermal deformation of a machine tool structure due to the heat generated during operation was analyzed, and embedded cooling channels were applied to exchange the heat generated during the operation to achieve thermal error suppression. Then, the finite volume method was used to simulate the effect of cooling oil temperature on thermal deformation, and the effect of thermal suppression was experimentally studied using a feed system combined with a cooler to improve the positioning accuracy of the machine tool. In this study, the supply oil temperature in the structural cooling channels was found to significantly affect the position accuracy of the moving table and moving carrier. If the supply oil temperature in the cooling channels is consistent with the operational ambient temperature, the position accuracy of the moving table in the Y direction and the moving carrier in the X and Z directions has the best performance under different feed rates. From the thermal suppression experiments of the embedded cooling channels, the positioning accuracy of the feed system can be improved by approximately 25.5 % during the dynamic feeding process. Furthermore, when the hydrostatic guideway is cooled and dynamic feeding is conducted, positioning accuracy can be improved by up to 47.8 %. The machining accuracy can be improved by approximately 60 % on average by using the embedded cooling channels in this study. Therefore, thermal suppression by the cooling channels in this study can not only effectively improve the positioning accuracy but also enhance machining accuracy, proving that the method is effective for enhancing machine tool accuracy.


2014 ◽  
Vol 651-653 ◽  
pp. 647-650
Author(s):  
Hai Tao Yu ◽  
Lie Chen ◽  
Chang Bing Zhou ◽  
Rui Wen Guo

With the demands of machine tool accuracy and stability for manufacturing are getting higher and higher, the effect of cooling oil is increasingly evident. And it is proved that cooling oil temperature is an important factor for machine cutting precision and stability. Continuous cutting test was carried on and values of over pin dial (M) were measured. The results show that it has large effect of cooling oil temperature on the stability of M-value. Subsequently, test of machine capability index (CMK) was carried on. And it was verified that the CMK of gear shaping machine is larger than 1.67. And the results show that the fluctuation of M values is the smallest when cooling oil temperature is 33°C. Lowest time costing for adjusting the processing system, highest cutting accuracy, and smallest value of stable amplitude for Gear Shaping Machine could be obtained at this condition.


Author(s):  
Steven Y. Liang ◽  
Albert J. Shih

Author(s):  
Yuqing Zhou ◽  
Xuesong Mei ◽  
Gedong Jiang ◽  
Nuogang Sun ◽  
Bai Shao

Simultaneous rotary-translational (R-T) axis motion error has significant influence on multi-axis machine tool precision. To improve multi-axis machine tool precision, axis motion error measurement and trace method are investigated in this study. A sensorless R-T axis motion error measurement and trace technology based on virtual bar is proposed. Firstly, the fundamental sensorless test principle is discussed. Then, the virtual-bar-based test path of a circular test though a rotary axis and two translational axes motion is scheduled. The mathematical model of motion error is established. Furthermore, to identify the error source, spatial error charts and some advanced signal processing and feature extraction technologies, such as wavelet transform and frequency analysis, are used. The analysis of experimental results shows that it is practical and efficient to use the virtual bar and the sensorless information to estimate motion error.


2018 ◽  
Vol 25 ◽  
pp. 338-343 ◽  
Author(s):  
Nikolas Theissen ◽  
Theodoros Laspas ◽  
Károly Szipka ◽  
Andreas Archenti

2018 ◽  
Vol 24 (3) ◽  
pp. 376-399 ◽  
Author(s):  
Abubaker Shagluf ◽  
Simon Parkinson ◽  
Andrew Peter Longstaff ◽  
Simon Fletcher

Purpose The purpose of this paper is to produce a decision support aid for machine tool owners to utilise while deciding upon a maintenance strategy. Furthermore, the decision support tool is adaptive and capable of suggesting different strategies by monitoring for any change in machine tool manufacturing accuracy. Design/methodology/approach A maintenance cost estimation model is utilised within the research and development of this decision support system (DSS). An empirical-based methodology is pursued and validated through case study analysis. Findings A case study is provided where a schedule of preventative maintenance actions is produced to reduce the need for the future occurrences of reactive maintenance actions based on historical machine tool accuracy information. In the case study, a 28 per cent reduction in predicted accuracy-related expenditure is presented, equating to a saving of £14k per machine over a five year period. Research limitations/implications The emphasis on improving machine tool accuracy and reducing production costs is increasing. The presented research is pioneering in the development of a software-based tool to help reduce the requirement on domain-specific expert knowledge. Originality/value The paper presents an adaptive DSS to assist with maintenance strategy selection. This is the first of its kind and is able to suggest a preventative strategy for those undertaking only reactive maintenance. This is of value for both manufacturers and researchers alike. Manufacturers will benefit from reducing maintenance costs, and researchers will benefit from the development and application of a novel decision support technique.


1999 ◽  
Vol 121 (3) ◽  
pp. 409-415 ◽  
Author(s):  
Biing-Wen Bair ◽  
Chung-Biau Tsay

This work uses the mathematical model of ZK-type dual-lead worm gear drive proposed in our recent work (1998). Based on the proposed mathematical model, coordinates and unit normals of the worm gear surface grid points can be determined and a data file subsequently formed. The data file is considered as the theoretical tooth surface data and then input into the computer of a three-dimensional coordinate measurement machine (3-D CMM) to numerically calculate the surface deviations of a real-cut worm gear. In addition, a computerized tooth surface measurement model compatible with the 3-D CMM is developed. Sensitivity analysis is also performed on machine-tool settings and tool-profile errors to the generated gear tooth surface variations. Minimization on gear tooth surface variations can be determined by applying the proposed measurement and calculation methods. In addition, optimum machine tool settings and tool-profile modifications are obtained by applying the developed computer simulation softwares. Moreover, the singular value decomposition (SVD) and sequential quadratic programming (SQP) methods are compared to establish the optimum machine-tool settings and resolve the minimum surface deviation problems.


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