Inclusive estimations of ball screw-based CNC feed drive system over positioning and pre-loading factor

2018 ◽  
Vol 38 (3) ◽  
pp. 303-313 ◽  
Author(s):  
Kuldeep Verma ◽  
R.M. Belokar

Purpose This paper aims to investigate the performance and positioning accuracy of computer numerical controlled (CNC) feed drive system using a ball screw-based pre-loading impact factor. Design/methodology/approach Initially, axial displacement of support bearings has been computed in relation to the different preload values. Among the computed values, a basic rule equation has been developed for the calculation of elongation in the bearings. The value of displacements computed from the developed equation has been considered as a pre-loading value, and its behavior on the feed drive system has been analyzed. Findings The elongation of bearings impacts the positioning accuracy and repeatability of the feed drive system and of CNC machines. Next, an analytical model for the rigorous assessment of CNC feed drive system has been designed and developed. The positioning accuracy of CNC machine in relation with different pre-loading values has been analyzed. Practical implications The results obtained from these investigations enhance the positioning accuracy of CNC machining centers. The optimum pre-loading value has been analyzed among the available ranges, and it has been proposed that optimal results have been achieved at 5 per cent of dynamic load rating. Originality/value This paper proposes improved explorations toward the performance of the CNC machines by optimizing the positioning accuracy through pre-loading. Finally, analytical estimations have been carried out to prove the validity of the proposal.

Author(s):  
Jun Zhang ◽  
Bo Li ◽  
Changxing Zhou ◽  
Wanhua Zhao

For semi-closed-loop computer numerical control machine tool, the pitch error of screw caused by thermal expansion can deteriorate the positioning accuracy of ball screw feed drive system. This study presents different prediction models for positioning error of ball screw feed drive system based on the mounting condition, where the total error is separated into geometric error and thermal error. The coefficients in the model are identified using the multiple linear regression method. The prediction model is validated and the error compensation is also done for the X axis of a three-axis computer numerical control milling machine. The test results show that the model developed can well predict the thermal error under any given temperature as well as position during the temperature rising process of ball screw, and it can greatly improve the system positioning accuracy through compensation.


2013 ◽  
Vol 694-697 ◽  
pp. 115-119
Author(s):  
Da Xing Zhao ◽  
Yong Yang ◽  
Wan Xu ◽  
Guo Long Ding ◽  
Ling Peng

High-speed high-precision CNC processing technology plays a very important position in the CNC machining industry,machine disturbance,however,an important factor affecting the machining accuracy,the ball screw feed drive as an important part of the machine directly affects the operating characteristics of the machine.Ball screw drive system,Solidworks,Ansys,Adams the establishment of machine tool,rigid-flexible couping the multibody dynamics model,the dynamic characteristic curve of the machine.Compared with the rigid body model simulation results verify the feasibility of rigid-flexible coupling modeling method,optimized to provide the basis of the structural design of the machine components.


2018 ◽  
Vol 10 (11) ◽  
pp. 168781401881235
Author(s):  
Yang Li ◽  
Jun Zhang ◽  
Dongxu Su ◽  
Changxing Zhou ◽  
Wanhua Zhao

Positioning error of the feed drive system has great influence of the machining quality. In order to guarantee the positioning accuracy, the linear grating scale is adopted to form a full-closed loop. However, due to the inner heat sources and environmental temperature variations, the linear grating scale could expand and the thermally induced positional deviation is generated. In this article, temperatures and positional deviations of the ball screw feed drive system and the linear motor feed drive system equipped with linear scales were tested. The factors that affect the positioning error were analyzed. Then, the temperatures and positioning coordinates were used as inputs to build the thermally induced positional deviation model of full closed-loop feed drive system. Based on the model, coordinate values of the machine tool were adjusted and the compensation was implemented. The testing results verified that after compensation, the positional deviations were greatly reduced.


2015 ◽  
Vol 799-800 ◽  
pp. 576-580 ◽  
Author(s):  
Yi Guang Shi ◽  
Hui Xiao ◽  
Jun Ao Zhang ◽  
Da Wei Zhang

This paper presents relationships between some vital parameters and the natural frequency of the ball screw feed drive system. A finite element model (FEM) of a machine tool feed drive system is established with joint parameters added in based on the SAMCEF software. Using the finite element model, the influences of the material properties of the worktable, the diameter of the ball screw and joint parameters on the natural frequency of axial vibration are derived. These results provide a reliable basis for the optimization design of the ball screw feed drive system.


Author(s):  
Jianmin Zhu ◽  
Tongchao Zhang ◽  
Jian Wang ◽  
Xiaoru Li

The dynamic characteristic parameters of mechanical joints are difficult to determine in theoretical modeling, dynamic simulation, and servo controller design for the ball screw feed drive system. Therefore, this study proposes a novel method for identifying the axial stiffness and damping parameters of the rolling joints in an assembled ball screw feed drive system. First, the proposed method deduces the axial vibration equations of the feed drive system with a harmonic excitation force exerted on its worktable. Second, the identification model of the axial stiffness and damping parameters of the rolling joints is established on the basis of the equations. Third, the identification equations are built by measuring the distance between the screw supporting points, the frequency, and the amplitude of the harmonic excitation force, as well as the amplitude of the axial vibration velocity of the screw end section. The axial stiffness and damping parameters of the rolling joints are finally determined by solving the identification equations using the genetic algorithm. With a ball screw feed drive system as the research object, the proposed method is used to identify the rolling joints’ axial stiffness and damping parameters of the ball screw assembly, as well as the left and the right bearing groups. The experiments show that the proposed method is correct, effective, and achieves high identification accuracy.


2021 ◽  
Author(s):  
Carlos E. Marquez-Garcia ◽  
Jesus Lopez-Gomez ◽  
Fermin Martinez-Solis ◽  
M. A. Diozcora Vargas-Trevino ◽  
Sergio Vergara-Limon ◽  
...  

2020 ◽  
Vol 34 (7) ◽  
pp. 2985-2995
Author(s):  
Gaiyun He ◽  
Panpan Shi ◽  
Dawei Zhang ◽  
Guangming Sun

Author(s):  
Ryuta Sato ◽  
Masaomi Tsutsumi

In this paper, a new modeling, and controller tuning method for feed drive systems is described. Typical feed drive systems consist of an AC servo motor, a ball screw, linear guides, and a servo controller. In order to design high performance systems, it is effective to make a model and analyze its behavior. In this study, a feed drive system is modeled by a vibration model with two degrees of freedom. Various kinds of motions are measured and simulated. The results of the experiment and simulation show that these motions are well simulated by the model. This means that the proposed model can accurately estimate the transfer function of the actual system. As a result, it is easy to design a controller based on the transfer function. The gains in the velocity control loop are calculated based on the partial model-matching method. Two PI and I-P velocity controllers are applied to the feed drive system. The step responses are then compared to each other. The position loop gain is calculated from the frequency response of the velocity control system. The proposed method is applied to an actual feed drive system, and it is confirmed that the proposed method yields comparable performance to the system designed by the conventional tuning way.


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