The Thermal Characteristics of the Ball Screw Feed System on a Gantry Machine Tool

2014 ◽  
Vol 490-491 ◽  
pp. 1008-1012
Author(s):  
Rui Jun Liang ◽  
Wen Hua Ye ◽  
Qun Qiang Chen ◽  
Xin Jie Zhao
Keyword(s):  
Temperature Field ◽  
Machine Tool ◽  
Thermal Equilibrium ◽  
Thermal Deformation ◽  
Thermal Structure ◽  
Ball Screw ◽  
Machining Accuracy ◽  
Feed Speed ◽  
Feed System ◽  
Gantry Machine Tool

With the increasing of machine tool feed speed, a large quantity of friction heat is generated on the ball screw system and will cause the temperature rising and thermal deformation along the ball screw that reduces the machining accuracy. The heat accumulated and dissipated are calculated to load to the established model of the Y feed system on a gantry machine tool. The stable temperature field at thermal equilibrium and the unstable temperature field before thermal equilibrium or with the variation of thermal load are gotten. From thermal structure analysis, the thermal deformation is derived. The FEM model is verified by the experiments carried out under the same condition with the simulation.

scholarly journals Effect of Supply Cooling Oil Temperature in Structural Cooling Channels on the Positioning Accuracy of Machine Tools

2019 ◽  
Vol 35 (6) ◽  
pp. 887-900 ◽  
Author(s):  
K.-Y. Li ◽  
W.-J. Luo ◽  
M.-H. Yang ◽  
X.-H. Hong ◽  
S.-J. Luo ◽  
...  
Keyword(s):  
Machine Tool ◽  
Thermal Deformation ◽  
Thermal Error ◽  
Machining Accuracy ◽  
Feed System ◽  
Positioning Accuracy ◽  
Cooling Channels ◽  
Position Accuracy ◽  
Machine Tool Accuracy ◽  
Volume Method

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.

Analysis of Thermal Error Model of Ball Screw Feed System Based on Experimental Data

2021 ◽  
Author(s):  
Jiancheng Yang ◽  
Changyou Li ◽  
Mengtao Xu ◽  
Yimin Zhang
Keyword(s):  
Experimental Data ◽  
Thermal Expansion ◽  
Machine Tool ◽  
Thermal Deformation ◽  
Axial Direction ◽  
Ball Screw ◽  
Machining Parameters ◽  
Feed System ◽  
The Impact ◽  
Screw Feed

Abstract In order to investigate the effect of thermal expansion on the ball screw feed system (BSFS) of a precision machine tool, theoretical modeling of and experimental study on thermally induced error are focused in this paper. A series of thermal experiments are conducted on the machine tool to measure the temperature of the main heat source and measuring points of BSFS. To classify the main heat sources and discuss the impact on the ball screw feed system separately. By the experimental data of ball screw system, the thermal model of screw shaft in the axial direction is analyzed and verified. Based on the heat generation and transfer analysis of ball screw system, thermal expansion of screw shaft in the axial direction is modeled mathematically. In addition, by analyzing the effects of machining parameters such as rotational speed, preloads and lead, we get the parameter influence of BSFS’s temperature rising and thermal deformation. This work can help us reduce thermal deformation effectively, and improve the precision of CNC machining.

scholarly journals Effect of Stiffness of Rolling Joints on the Dynamic Characteristic of Ball Screw Feed Systems in a Milling Machine

2015 ◽  
Vol 2015 ◽  
pp. 1-11 ◽  
Author(s):  
Dazhong Wang ◽  
Yan Lu ◽  
Tongchao Zhang ◽  
Keyong Wang ◽  
Akira Rinoshika
Keyword(s):  
Machine Tool ◽  
Dynamic Characteristic ◽  
Calculation Method ◽  
Ball Screw ◽  
Fe Model ◽  
Milling Machine ◽  
Cnc Milling ◽  
Feed System ◽  
Cnc Milling Machine ◽  
Screw Feed

Dynamic characteristic of ball screw feed system in a milling machine is studied numerically in this work. In order to avoid the difficulty in determining the stiffness of rolling joints theoretically, a dynamic modeling method for analyzing the feed system is discussed, and a stiffness calculation method of the rolling joints is proposed based on the Hertz contact theory. Taking a 3-axis computer numerical control (CNC) milling machine set ermined as a research object, the stiffness of its fixed joint between the column and the body together with the stiffness parameters of the rolling joints is evaluated according to the Takashi Yoshimura method. Then, a finite element (FE) model is established for the machine tool. The correctness of the FE model and the stiffness calculation method of the rolling joints are validated by theoretical and experimental modal analysis results of the machine tool’s workbench. Under the two modeling methods of joints incorporating the stiffness parameters and rigid connection, a theoretical modal analysis is conducted for the CNC milling machine. The natural frequencies and modal shapes reveal that the joints’ dynamic characteristic has an important influence on the dynamic performance of a whole machine tool, especially for the case with natural frequency and higher modes.

scholarly journals Analysis on Dynamic Contact Characteristics and Dynamic Stiffness Estimating Method of Single Nut Ball Screw Pair Based on the Whole Rolling Elements Model

2020 ◽  
Vol 10 (17) ◽  
pp. 5795
Author(s):  
Ye Chen ◽  
Chunyu Zhao ◽  
Zhenjun Li ◽  
Zechen Lu
Keyword(s):  
Machine Tool ◽  
Mass Production ◽  
Contact Stiffness ◽  
Dynamic Stiffness ◽  
Dynamic Contact ◽  
Ball Screw ◽  
Cnc Machine Tool ◽  
Cnc Machine ◽  
Feed System ◽  
Stiffness Model

The purpose of this paper is investigating the characteristics of dynamic contact and dynamic stiffness of the single nut ball screw pair (SNBSP). Then a new sensorless method is proposed to extract the SNBSP dynamic contact stiffness of a mass production CNC machine tool feed system. First of all, the transformation relationship between each coordinate system of SNBSP is established. Secondly, the dynamic model of all ball–raceway contact pairs is established. Based on this, a dynamic contact stiffness model is established. The dynamic contact parameters are obtained by the numerical method. It is found that the influence of screw speed on screw and nut raceway normal force distribution are opposite. This will affect the variations of dynamic contact stiffness. It is also clear that the effect of axial load on dynamic stiffness is significant. Then, an effective method is proposed to estimate the dynamic contact stiffness of a mass production CNC machine tool feed system without any external sensors. The axial force of feed system is estimated by using torque current of servo motor. Current signals can be obtained through FANUC Open CNC API Specifications (FOCAS) library functions, and then dynamic contact stiffness can be calculated through the stiffness model without external sensors. Finally, a feed system dynamic model is built, and the contact model and sensorless stiffness estimating method are verified by experiments in this dynamic system.

The Stiffness Analysis and Modeling Simulation of Ball Screw Feed System

2010 ◽  
Vol 97-101 ◽  
pp. 2914-2920 ◽  
Author(s):  
Qin Wu ◽  
Zhi Yuan Rui ◽  
Jian Jun Yang
Keyword(s):  
Machine Tool ◽  
Control Strategy ◽  
Feedforward Control ◽  
Dynamic Performance ◽  
Numerical Control ◽  
Ball Screw ◽  
Axial Stiffness ◽  
Cnc Machine Tool ◽  
Cnc Machine ◽  
Feed System

The computer numerical control (CNC) machine tool was investigated and the dynamics model for the servo feed system was established. Based on the fixing constraint of the ball screw, the mathematical models of axial stiffness and torsion stiffness are constructed. According to the effects of stiffness on the dynamic performance, the simulation model for CNC machine tool feed system with stiffness considered was set up by the dynamic simulation tool Simulink, and a curve representing the performance of the system was obtained. To reduce the effect of stiffness on the system, the feedforward control strategy is used for stiffness compensation. The simulation results show that the stability and response performances of the system are improved and the steady-state error of the system is reduced by the control strategy.

Numerical Simulation Analysis of Temperature Field for Motorized Spindle of High-Grade CNC Machine Tool Based on ANSYS

2010 ◽  
Vol 455 ◽  
pp. 33-36 ◽  
Author(s):  
C.Q. Li ◽  
Xiao Dong Zhang ◽  
Q. Zhang ◽  
H. Li
Keyword(s):  
Temperature Field ◽  
Machine Tool ◽  
High Speed ◽  
Thermal Deformation ◽  
Simulation Analysis ◽  
Transient Temperature ◽  
High Grade ◽  
Cnc Machine Tool ◽  
Cnc Machine ◽  
Motorized Spindle

To solve the problems that the thermal deformation of the High-Grade CNC machine tool has much effect on accuracy and quality of the produces, the structure characteristics of the high speed motorized spindle is firstly introduced in this paper. Then one type of motorized spindle and supporting structure are selected, and the thermal boundary parameters are calculated. Much more the static and transient temperature field are simulated by using FEA software ANSYS in one working condition. At last, the main measures to improve the uneven temperature field and the plans to reduce the thermal deformation are put forward, which are provided some technical bases for the equipment to achieve the high-speed and high-precision machining.

scholarly journals Heat Source Forecast of Ball Screw Drive System Under Actual Working Conditions Based on On-Line Measurement of Temperature Sensors

Sensors ◽  
2019 ◽  
Vol 19 (21) ◽  
pp. 4694 ◽  
Author(s):  
Zhenjun Li ◽  
Zechen Lu ◽  
Chunyu Zhao ◽  
Fangchen Liu ◽  
Ye Chen
Keyword(s):  
Temperature Field ◽  
Heat Source ◽  
Working Conditions ◽  
Inverse Method ◽  
Temperature Sensors ◽  
Ball Screw ◽  
Time Varying ◽  
Feed System ◽  
Thermal Network ◽  
On Line

In view of the time-varying complexity of the heat source for the ball screw feed system, this paper proposes an adaptive inverse problem-solving method to estimate the time-varying heat source and temperature field of the feed system under working conditions. The feed system includes multiple heat sources, and the rapid change of the moving heat source increases the difficulty of its identification. This paper attempts to develop a numerical calculation method for identifying the heat source by combining the experiment with the optimization algorithm. Firstly, based on the theory of heat transfer, a new dynamic thermal network model was proposed. The temperature data signal and the position signal of the moving nut captured by the sensors are used as input to optimize the solution of the time-varying heat source. Then, based on the data obtained from the experiment, finite element software parametric programming was used to optimize the estimate of the heat source, and the results of the two heat source prediction methods are compared and verified. The other measured temperature points obtained by the experiment were used to compare and verify the inverse method of this numerical calculation, which illustrates the reliability and advantages of the dynamic thermal network combined with the genetic algorithm for the inverse method. The method based on the on-line monitoring of temperature sensors proposed in this paper has a strong application value for heat source and temperature field estimation of complex mechanical structures.

Thermal Characteristics Analysis of Nuclear Power CNC Wheel Groove Milling Machine Based on Finite Element

2013 ◽  
Vol 816-817 ◽  
pp. 1100-1104
Author(s):  
Zhi Wei Li ◽  
Dan Lu Song
Keyword(s):  
Finite Element ◽  
Machine Tool ◽  
Nuclear Power ◽  
Optimization Design ◽  
Thermal Structure ◽  
Thermal Characteristics ◽  
Machining Accuracy ◽  
Accuracy Evaluation ◽  
Milling Machine ◽  
Element Analysis

For nuclear power CNC wheel groove milling machine in the work under the influence of a variety of heat sources, establish the finite element model of machine, using finite element analysis software ANSYS, analysis and thermal-structure coupling of heat source in the processing state mechanism, thermal key points out machine, the effect of deformation on the machine geometric accuracy evaluation of heat, and the machine thermal optimization analysis of corresponding, deformation of machine in the three direction. The results show that: the machine in machining spindle heat is an important factor affecting the machining accuracy of machine tools, and heat through various ways to machine tool bed, causing warping, guide rail bending, through this analysis provides reference for analysis and optimization design for the machine tool thermal deformation.

scholarly journals Machining Accuracy Enhancement of a Machine Tool by a Cooling Channel Design for a Built-in Spindle

2020 ◽  
Vol 10 (11) ◽  
pp. 3991
Author(s):  
Kun-Ying Li ◽  
Win-Jet Luo ◽  
Shih-Jie Wei
Keyword(s):  
Machine Tool ◽  
Thermal Deformation ◽  
Simulation Analysis ◽  
Machining Accuracy ◽  
Manufacturing Cost ◽  
Cooling Channel ◽  
Channel Design ◽  
Warm Up ◽  
Maximum Decrease ◽  
Operational Time

This study presents a multiphysics simulation analysis that was performed for the cooling channel of a built-in spindle. The design of experiments (DOE) method was employed to optimize the dimension of the cooling channel, and a practical machining experiment was performed to validate the effect of the design. In terms of the temperature, pressure drop, thermal deformation, manufacturing cost, and initial cost considerations, the paralleling type cooling channel of the front bearing and the helical type cooling channel of the motor were adopted in the study. After the optimal design of the cooling channel was applied, the bearing temperature was reduced by a maximum decrease of 6.7 °C, the spindle deformation decreased from 53.8 μm to 30.9 μm, and the required operational time for attaining the steady state of the machine tool was shortened from 185.3 min to 132.6 min. For the machining validation, the spindle with the optimal cooling channel design was employed for vehicle part machining, the flatness of the finished workpiece was increased by 61.3%, and the surface roughness (Ra) was increased by 52%. According to the findings for the optimal cooling channel, when the spindle cooling efficiency is increased by the optimal cooling channel design, the thermal deformation and warm-up period can be reduced effectively, and the machining precision can be enhanced. This method is an efficient way to increase the accuracy of a machine tool.

scholarly journals Study of the Dynamic Characteristics of Ball Screw with a Load Disturbance

2016 ◽  
Vol 2016 ◽  
pp. 1-10 ◽  
Author(s):  
Zhe Du ◽  
Xiao-Lan Zhang ◽  
Tao Tao
Keyword(s):  
Machine Tool ◽  
Dynamic Characteristics ◽  
Numerical Control ◽  
Hertzian Contact ◽  
Ball Screw ◽  
Machining Accuracy ◽  
Contact Deformation ◽  
Nc Machine Tool ◽  
Load Disturbance ◽  
Nc Machine

The dynamic character of ball screw is the key factor that influences the machining accuracy of numerical control (NC) machine tool. To improve the dynamic characteristics of the NC machine tool, it is necessary to study the dynamic characteristics of a ball screw. In this paper, the kinematics of a ball screw mechanism (BSM) are studied to expound the dynamic process of the drive, and the load disturbance is considered to analyze the contact deformation based on the Hertzian contact theory. The velocity relationships among the ball, screw, and nut are analyzed, and the influence of the contact deformation on the dynamic characteristics is simulated and investigated experimentally. The results show that the relationships between the contact deformation, which is affected by the material characteristics, the contact angle, and the load of nut are nonlinear. The contact deformation is a factor that cannot be ignored when considering the dynamic machining error of high-speed and high-precision machine tools.

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