scholarly journals Improvement of machine tool accuracy through ball screw location optimisation in relation to the guideways of the axes

2020 ◽  
Vol 916 ◽  
pp. 012115
Author(s):  
A Stoica ◽  
G Stan
Keyword(s):  
Machine Tool ◽  
Ball Screw ◽  
Machine Tool Accuracy

High-Precision Tracking Control of Machine Tool Feed Drives Based on ADRC

2016 ◽  
Author(s):  
Chengyong Zhang ◽  
Yaolong Chen
Keyword(s):  
Machine Tool ◽  
High Precision ◽  
Tracking Control ◽  
Position Control ◽  
Feedback System ◽  
Pi Controller ◽  
Ball Screw ◽  
Feed Drives ◽  
Precision Tracking ◽  
Precision Tracking Control

In this paper, the active-disturbance-rejection control (ADRC) is applied to realize the high-precision tracking control of CNC machine tool feed drives. First, according to the number of the feedback channel, the feed systems are divided into two types: signal-feedback system, e.g., linear motor and rotary table, and double-feedback system, e.g., ball screw feed drive with a load/table position feedback. Then, the appropriate controller is designed to ensure the closed-loop control performance of each type of system based on the idea of ADRC. In these control frameworks, the extended state observers (ESO) estimate and compensate for unmodeled dynamics, parameter perturbations, variable cutting load, and other uncertainties. For the signal-feedback system, the modified ADRC with an acceleration feedforward term is used directly to regulate the load/table position response. However, for the double-feedback system, the ADRC is applied only to the motor position control, and a simple PI controller is used to achieve the accurate position control of the load. In addition, based on ADRC feedback linearization, a novel equivalent-error-model based feedforward controller is designed to further improve the command following performance of the double-feedback system. The experimental results demonstrate that the proposed controllers of both systems have better tracking performance and robustness against the external disturbance compared with the conventional P-PI controller.

The Coupling Characteristic of HSK Tool-Holder/Spindle Interface for High-Speed NC Machine Tool

2014 ◽  
Vol 590 ◽  
pp. 121-125 ◽  
Author(s):  
Wen Kai Jie ◽  
Jian Chen ◽  
Deng Sheng Zheng ◽  
Gui Cheng Wang
Keyword(s):  
Machine Tool ◽  
Rotational Speed ◽  
High Speed ◽  
Nonlinear Finite Element Method ◽  
High Rotational Speed ◽  
Tool Holder ◽  
Nc Machine Tool ◽  
Machine Tool Accuracy ◽  
Nc Machine ◽  
Coupling Characteristic

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.

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.

Modal Analysis of Ball Screw Based on ANSYS Software

2011 ◽  
Vol 314-316 ◽  
pp. 1981-1986 ◽  
Author(s):  
Qing Ke Yuan ◽  
Ya Nan Du ◽  
Yao Ding ◽  
Tong Le Wang
Keyword(s):  
Numerical Model ◽  
Machine Tool ◽  
Modal Analysis ◽  
Structure Analysis ◽  
Ball Screw ◽  
Feeding System ◽  
Ansys Software ◽  
Intrinsic Frequency ◽  
Vibration Model

Ball screw is an important part in the machine tool feeding system. This paper researches on the ball screw, establishes the 3D virtual numerical model by Pro/engineer. Modal analysis of ball screw is carried out in three different cases by ANSYS, then gets the intrinsic frequency and vibration model of ball screw. It provides reliable reference for further structure analysis of ball screw.

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 on Effect of Cooling Oil Temperature on Cutting Stability of Gear Shaping Machine

2014 ◽  
Vol 651-653 ◽  
pp. 647-650
Author(s):  
Hai Tao Yu ◽  
Lie Chen ◽  
Chang Bing Zhou ◽  
Rui Wen Guo
Keyword(s):  
Machine Tool ◽  
Processing System ◽  
Cutting Stability ◽  
Capability Index ◽  
Cutting Test ◽  
Machine Tool Accuracy ◽  
The Stability ◽  
Gear Shaping ◽  
Accuracy And Stability

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.

Machine Tool Accuracy and Metrology

2015 ◽  
pp. 95-111
Author(s):  
Steven Y. Liang ◽  
Albert J. Shih
Keyword(s):  
Machine Tool ◽  
Machine Tool Accuracy

scholarly journals Virtual machining system simulator: analysis of machine tool accuracy

2018 ◽  
Vol 25 ◽  
pp. 338-343 ◽  
Author(s):  
Nikolas Theissen ◽  
Theodoros Laspas ◽  
Károly Szipka ◽  
Andreas Archenti
Keyword(s):  
Machine Tool ◽  
Virtual Machining ◽  
Machine Tool Accuracy ◽  
Machining System

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.

Sign in / Sign up

Export Citation Format

Share Document