A Novel High Speed/High Precision Ball Screw

Zhe-Zhu Xu,류성기,Xiaojing Liu,최종훈 한국정밀공학회 2013 International Journal of Precision Engineering and Vol. No.

As a tried and tested technology, ball screw drive systems are still used in a majority of machine tools which can meet the demands of higher productivity and tight part tolerances due to their low cost and high degree of stiffness. High speed ball screw drive system generates more heat and it results in greater positioning error, adversely affecting the accuracy of high precision machined parts. In this paper, a novel/well designed high speed/high precision nut air cooling ball screw system was developed to avoid thermal errors which affect the positioning accuracy and the temperature rise of ball screw. In order to discuss the effectiveness of the developed high speed/high precision nut air cooling ball screw system, a series of tests was done. As the results, it shows that the positioning accuracy will significantly improve with the use of the nut air cooling ball screw drive system shown in this paper.

Study on Positioning Accuracy of Nut/Shaft Air Cooling Ball Screw for High-precision Feed Drive

Zhe-Zhu Xu,류성기,Xiaojing Liu 한국정밀공학회 2014 International Journal of Precision Engineering and Vol.15 No.1

Thermal error, which is of the machine tool feed system, is the key factor leading to dimensional error of machined work-piece. This paper presents a new approach in thermal error control instead of thermal error compensation. For the investigation of thermal error control, a novel/well designed high speed/high precision nut/screw air cooling ball screw system was developed to avoid thermal errors which affect the positioning accuracy of ball screw feed drive system. In order to discuss the effectiveness of the developed high speed/high precision nut/screw air cooling ball screw system, a series of tests was done. As the results, it shows that the positioning accuracy will significantly improve with the use of the nut/screw air cooling ball screw feed drive system shown in this paper.

Study on a Novel Thermal Error Compensation System for High-Precision Ball Screw Feed Drive (2nd Report: Experimental Verification)

Zhe-Zhu Xu,Chang Choi,Long-jun Liang,Dong-Yang Li,류성기 한국정밀공학회 2015 International Journal of Precision Engineering and Vol.16 No.10

Real-time thermal error compensation of machine tool feed drive in general can be separated into three steps such as modeling, measurement and compensation. In the previous report, as the parts of the thermal error compensation system, component heat generation, compensation method, thermal model, mathematic model and calculation method were studied respectively. And a series of simulations was carried out in several kinds of working condition. And then, in order to discuss the correctness of the developed ball screw thermal error compensation system, a series of tests contains axial deformation, positioning accuracy, temperature variation and temperature distribution was carried out in the same working condition of prediction. As the results, the test data well confirmed the correctness of the developed ball screw thermal error compensation system.

Study on a Novel Thermal Error Compensation System for High-Precision Ball Screw Feed Drive (1st Report: Model, Calculation and Simulation)

Zhe-Zhu Xu,최창,Long-jun Liang,Dong-Yang Li,류성기 한국정밀공학회 2015 International Journal of Precision Engineering and Vol.16 No.9

In general, in order to compensate the thermal error or the positioning error of a ball screw feed drive system, the actual temperature or positioning data feedback was needed. The traditional thermal error compensation system of ball screw feed drive is highly dependent on the feedback temperature or positioning data. Because of the overdependence to measuring technique, increasing of compensation system cost and decreasing of productivity level will be an inevitable trend in a machine tool. This paper presents a new approach in ball screw thermal error compensation system which can work without any temperature or positioning feedback. As the parts of the thermal error compensation system, component heat generation, compensation method, thermal model, mathematic model and calculation method were studied respectively. In order to verify correctness and generality of the developed thermal model and the thermal error compensation system, a series of simulations was carried out in several kinds of working condition. Through the series of simulations with the thermal model, calculation method and simulation conditions, deformation characteristics and thermal behavior of the prototype ball screw system have been obtained.

Study on Modular Modeling and Performance Evaluation of a Conical Gear for Marine Transmission System

Zhe-Zhu Xu,Jun-seong Kim,김래성,Dong-Yang Li,류성기 한국정밀공학회 2015 International Journal of Precision Engineering and Vol. No.

Conical involute gears, which are also known as beveloid gears, are the involute gears with cone-shape gear body rather than cylindrical gear body. Generally, conical gears are used in anti-backlash transmission systems and marine transmission systems. In marine transmission system, in order to obtain optimal propulsive force, 7-14 degree inclination angle was needed. In this paper, a 7 degree cone angle conical gear used in 375 kW class marine power transmission system was selected as research objective. And in order to establish the design theory of conical gear, a design system named conical gear modular modeling system was developed. The prototype conical gear was developed by the above design system to be used to simulate in a certain condition. The simulated and optimized prototype conical gear was manufactured which is as a specimen to complete a series of performance tests which contains gear tooth profile test and contact rate test. As the results, the developed conical gear can well meet the performance requirements of the 375 kW class marine power transmission system.

A Study on Improvement of Ball Screw System Positioning Error with Liquid-Cooling

Xu, Zhe-Zhu,Liu, Xiao-Jing,Choi, Chong-Hun,Lyu, Sung-Ki 한국정밀공학회 2012 International Journal of Precision Engineering and Vol.13 No.12

The demand for higher productivity and tight part tolerances requires machine tools to have faster and more accurate feed drive systems. As tried and tested technology, ball screw drive systems are still used in a majority of machine tools due to their low cost and high degree of stiffness. A high-speed ball screw drive system generates more heat and results in greater positioning error, adversely affecting the accuracy of machined parts. In this paper, we discuss the placement of a liquid-cooling system using water, coolant oil, light oil and cutting oil as coolants in a ball screw shaft to avoid thermal errors and achieve temperature equilibrium faster. In order to estimate the positioning error and thermal distribution of the ball system and effectiveness of the liquid-cooling system, all possible heat gain-loss sources were analyzed and considered calculation factors. The following paper also presents degree of positioning error improvement when a circulation liquid-cooling system and forced liquid-cooling system were employed. When comparing the predictions and the experimental results, we can see very significant cooling performance and a high degree of consistency between prediction and reality.

Improvement of Positioning Error on a Ball Screw by Cooling System

Xu, Zhe Zhu,Zhang, Qi,Lyu, Sung Ki Trans Tech Publications, Ltd. 2011 Applied Mechanics and Materials Vol.86 No.-

<P>A high speed ball screw system generates more heat naturally and resultant more thermal expansion, which adversely affects the accuracy of positioning. Therefore, an air cooling system was set in ball screw shaft in this paper to dominate the thermal error and achieve temperature equilibrium faster. In order to estimate the thermal error of ball screw system and effectiveness of air cooling system, thermal behavior models of finite element method and modified lumped capacitance method were developed separately which includes the heat generation power of the main heat source of the ball screw system and other boundary conditions. The completed models were used to simulate the temperature distribution, thermal deformation and air cooling performance. Compared with experiments, it is shown that these methods can well predict the air cooling performance.</P>

Study on Thermal Behavior Analysis of Nut/Shaft Air Cooling Ball Screw for High-Precision Feed Drive

Zhe-Zhu Xu,류성기,Xiaojing Liu 한국정밀공학회 2014 International Journal of Precision Engineering and Vol.15 No.1

In a machine tool, continuous usage causes heat generation at the moving elements and this heat causes expansion of the various structural elements of the machine tool. The main direction of current research about machine tool thermal error is that named thermal error compensation. This paper presents a new approach in thermal error control instead of thermal error compensation and applied on a ball screw feed drive system. Ball screw is the key contributor to the thermal error of a machine tool which leading to dimensional error of machined work-piece. A novel/well designed high speed/high precision nut/screw air cooling ball screw system was developed to control thermal errors on a machine tool feed drive system. In order to discuss the effectiveness of the developed high speed/high precision nut/screw air cooling ball screw system, a series of tests was done. In this paper, experimental thermal behavior of nut/screw air cooling ball screw system for high-precision feed was discussed. As the results, relatively big temperature rising presented through the whole test process in no cooling condition and “Learning curve” phenomenon presented in the cooling cases. And the dominated temperature rising area covered the nut moving range completely.

A Study on Improvement of Ball Screw System Positioning Error with Liquid-Cooling

Zhe-Zhu Xu,류성기,Xiaojing Liu,최종훈 한국정밀공학회 2012 International Journal of Precision Engineering and Vol. No.

The demand for higher productivity and tight part tolerances requires machine tools to have faster and more accurate feed drive systems. As tried and tested technology, ball screw drive systems are still used in a majority of machine tools due to their low cost and high degree of stiffness. A high-speed ball screw drive system generates more heat and results in greater positioning error,adversely affecting the accuracy of machined parts. In this paper, we discuss the placement of a liquid-cooling system using water,coolant oil, light oil and cutting oil as coolants in a ball screw shaft to avoid thermal errors and achieve temperature equilibrium faster. In order to estimate the positioning error and thermal distribution of the ball system and effectiveness of the liquid-cooling system, all possible heat gain-loss sources were analyzed and considered calculation factors. The following paper also presents degree of positioning error improvement when a circulation liquid-cooling system and forced liquid-cooling system were employed. When comparing the predictions and the experimental results, we can see very significant cooling performance and a high degree of consistency between prediction and reality.

Study on Simulation and Calculation Method of Thermal Error Compensation System for a Ball Screw Feed Drive

Zhe Zhu Xu(허철수),Chang Choi(최창),Lae-Sung Kim(김래성),Kwon-In Baek(백권인),Sung-ki Lyu(류성기) 한국기계가공학회 2017 한국기계가공학회지 Vol.16 No.2

Due to the requirement of the development of the precision manufacturing industry, the accuracy of machine tools has become a key issue in this field. A critical factor that affects the accuracy of machine tools is the feed system, which is generally driven by a ball screw. Basically, to improve the performance of the feed drive system, which will be thermally extended lengthwise by continuous usage, a thermal error compensation system that is highly dependent on the feedback temperature or positioning data is employed in the machine tool system. Due to the overdependence on measuring technology, the cost of the compensation system and low productivity level are inevitable problems in the machine tool industry. This paper presents a novel feed drive thermal error compensation system method that could compensate for thermal error without positioning or temperature feedback. Regarding this thermal error compensation system, the heat generation of components, principal of compensation, thermal model, mathematic model, and calculation method are discussed. As a result, the test data confirm the correctness of the developed feed drive thermal error compensation system very well.