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Li X.,Qiqihar University | Li X.,Qiqihar CNC Equipment Corporation Ltd. | Bao L.,Qiqihar University | Wang S.,Qiqihar University | And 7 more authors.
Advanced Materials Research | Year: 2012

The rapid growth of modern technology place greater demand on electronic products' performance and quality. As for the printed circuit board (PCB) assembly of electronic components through surface mounting technology (SMT), high-pixel charge coupled device (CCD) can only screen local images during image collection because of its limited vision. A rapid image mosaic technology has been proposed to seamlessly stitch the local images with overlapping boundaries. The complete image of PCB assembly has been acquired through rapid area matching method within double Mark points and Mark circle. The experiment results show that this method can greatly reduce the image-mosaic time and fairly improve the real-time performance of modern automatic optical inspection (AOI) equipment. Furthermore, such method avoids the alignment error from the characteristic points for noise jamming or noise shielding, and therefore obtains better robustness. © (2012) Trans Tech Publications, Switzerland.


Yu X.,Harbin University of Science and Technology | Sui J.,Harbin University of Science and Technology | Meng X.,Heilongjiang Polytechnic | Wu X.,Harbin University of Science and Technology | And 3 more authors.
Journal of Computational and Theoretical Nanoscience | Year: 2015

This paper presents a simulation and experimental research concerning oil seal edge effect on the lubrication characteristics of a fluid film bearing. The Computational Fluid Dynamics and lubrication theory have been used to compute the lubrication characteristics such as recess pressure, recess temperature and fluent velocity of a circular recess oil film bearing with different oil seal edge width. The oil seal edge width has been optimized. A experimental setup is established for testing pressure field of fluid film bearing after optimization oil seal edge width, and experimental results show that experimental data are basically identical with the simulation results, and demonstrate the validity of the proposed numerical simulation method. The results demonstrate that bearing oil seal edge width has a great influence on the behavior of fluid film bearing and indicate that a proper selection of the oil seal edge width is essential to get an improved performance from a constant flow hydrostatic thrust bearing. Copyright © 2015 American Scientific Publishers. All rights reserved.


Yu X.-D.,Harbin University of Science and Technology | Fu X.,Harbin University of Science and Technology | Meng X.-L.,Heilongjiang Polytechnic | Liu D.,Harbin University of Science and Technology | And 2 more authors.
Journal of Computational and Theoretical Nanoscience | Year: 2015

The simulation concerning temperature performance of hydrostatic thrust bearing with circular recesses is carried out considering the changes in viscosity in order to solve the thermal deformation of the hydrostatic thrust bearing in the heavy computer numerical control (CNC) equipment. The three-dimensional temperature field of gap fluid between the rotary worktable and the base is computed based on a three-dimensional TEHD model. The influence of the rotational speed and viscosity on the bearing temperature performance is studied based on computational fluid dynamics (CFD) and lubrication theory, and the method reveals the temperature distribution law. A test rig is designed for testing the temperature of hydrostatic thrust bearing with circular recess. Good agreement has been obtained between predicted theoretical performance and that experimentally measured. The results demonstrate that rotational speed, oil viscosity, bearing recess size and location have a great influence on the temperature performance of hydrostatic thrust bearing. This study is expected to serve as a theoretical basis for design and development of the heavy computer numerical control equipment. Copyright © 2015 American Scientific Publishers All rights reserved.


Zhang Y.,Harbin University of Science and Technology | Yu Z.,Harbin University of Science and Technology | Chen Y.,Harbin University of Science and Technology | Shao J.,Harbin University of Science and Technology | And 2 more authors.
High Technology Letters | Year: 2014

In order to improve the cutting stiffness, the paper studies the vertical hydrostatic bearing in the slide when a ram is in feed process. The change of the oil film thickness on hydrostatic guide rail and the curve of the oil film thickness in various cutting forces are calculated and a relation model through theoretical analysis method is derived. The pressure field of the guide rail recess is simulated based on the finite volume method and demonstrated through experiments. The study is of vital theoretical significance for the improvement of machining accuracy of numerical control machines and the entire computer numerical control (CNC) equipment and provides valuable theoretical basis for the design of hydrostatic guide rail in engineering practice. Copyright © by HIGH TECHNOLOGY LETTERS PRESS


Yu X.-D.,Harbin University of Science and Technology | Sun D.-D.,Harbin University of Science and Technology | Meng X.-L.,Heilongjiang Polytechnic | Wu X.-G.,Harbin University of Science and Technology | And 3 more authors.
Journal of Computational and Theoretical Nanoscience | Year: 2015

The oil film thickness of a hydrostatic bearing is an important indicator of lubrication characteristics of a multi-pad hydrostatic thrust bearing, lubrication characteristics of hydrostatic thrust bearing are affected significantly by the rotational speed of the worktable, especially under the condition of high speed and heavy loading, and its effect is more significant. A multi-pad hydrostatic thrust bearing with circular recess is taken as research objects, the relation between oil film thickness and rational speed of the worktable is deduced by using lubricating theory and tribology principle. A test rig is designed for testing the oil film thickness of the above bearing, and a proving experiment is carried out. The calculated results qualitatively agree well with the experimental data, it has been found that by increasing the rotational speed the volume flow rate of efflux from the oil recess and the shear heat of the oil recess are increased, and lubricating oil viscosity decline sharply, oil film grow thin quickly, together with bearing friction pair uneven deformation, local bearing friction pair appear boundary lubrication or dry friction, and then happen tribology failure. The study provides the basic data for the hydrostatic thrust bearing design and lubrication, and implements of the prediction of the hydrostatic thrust bearing lubrication characteristics, and reaches the purpose of reducing economic loss. Copyright © 2015 American Scientific Publishers.


Li X.B.,Qiqihar University | Li X.B.,Harbin University of Science and Technology | Li X.B.,Qiqihar CNC Equipment Corporation Ltd. | Shi Z.M.,Qiqihar CNC Equipment Corporation Ltd. | And 4 more authors.
Key Engineering Materials | Year: 2012

For great progress in heat pipe technology, a micro heat pipe has become an ideal heat dissipating device in high heat-flux electronic products, and capillary limit is the main factor affecting its heat transfer performance. Based on analyses of capillary limit and currently commonly-used groove structures, this paper built capillary limit models for micro heat pipes with dovetail-groove, rectangular-groove, trapezoidal-groove and V-groove wick structures respectively for theoretical analyses. The analysis results show that better heat transfer performances can be obtained in micro heat pipes with small-angle dovetail (i.e. a sector structure), rectangular and small-angle trapezoidal grooved wick structures when groove depth is 0.2-0.3mm and top-width-to-depth ratio is 1.2-1.5. © (2012) Trans Tech Publications, Switzerland.


Li X.,Qiqihar University | Li X.,Qiqihar CNC Equipment Corporation Ltd. | Li X.,Harbin University of Science and Technology | Wang J.,Qiqihar University | And 3 more authors.
Heat and Mass Transfer/Waerme- und Stoffuebertragung | Year: 2013

Since heat flux increases sharply yet cooling space in microelectronic and chemical products gradually decreases, a micro heat pipe has been an ideal device for heat transfer for high heat-flux products, and its performance depends largely on its capillary limit. This study proposed an integrated utilization of the advantages of lower backflow resistance to working fluid in trapezium-grooved-wick micro heat pipes and greater capillary force in sintered-wick micro heat pipes; first the factors that are crucial to both types' heat transfer performances were analyzed, and then mathematical modeling was built for capillary limit of a micro heat pipe with the compound structure of sintered wick on trapezium-grooved substrate, and finally heat transfer limits for micro heat pipes with a trapezium-grooved wick, a sintered wick and with a compound structure were tested through experiments. Both the theoretical analysis and experimental results show that for a micro heat pipe with proposed compound structure, its capillary limit is superior to that of a micro heat pipe with a simplex sintered wick or trapezium-grooved wick. © 2012 Springer-Verlag Berlin Heidelberg.


Wang J.,Qiqihar CNC Equipment Corporation Ltd. | Wang F.,Qiqihar University | Du X.,Qiqihar University | Wang S.,Qiqihar University
Applied Mechanics and Materials | Year: 2012

With a high demand of clients to the precision and production efficiency about the CNC lathe, there is also a high demand to the precision of the sword of the tool checking instrument. In order to raise the precision of the sword and decrease the time of aligning tools, the thesis designs an auto-checking instrument applied on in-machine touch CNC lathe tool, and analyses its error. It proves that this auto-checking instrument has a wide size range and can locate once the size of the lathe tool. Its accuracy of the X-axis can be 0.02mm, of the Z-axis can be 0.025mm. It improves effectively the precision and production efficiency of the aligning knife, reduces labor cost. It has high practical value. © (2012) Trans Tech Publications, Switzerland.


Wang J.,Qiqihar CNC Equipment Corporation Ltd | Du X.,Qiqihar University | Hu Q.,Qiqihar University | Wang S.,Qiqihar University
Applied Mechanics and Materials | Year: 2012

With the rapid development of science and technology, Lathe will be sure to develop in the direction of high speed, high precision and high stability as the most basic and important production equipment in industry. The spindle is the one of important component in the lathe, of which static and dynamic characteristics is directly related to the machining precision and machining stability, and the performance of spindle system directly affects the overall machine specifications. Through the analysis of the characteristics of spindle, the ways and means of the spindle analysis are studied. For the requirements of static and dynamic characteristics analysis in the process of spindle design on high-precise CNC lathes hydrostatic, direct-drive spindle motor mode is used. Three-supporting structure is adapted in the layout of spindle bearing in order to improve the accuracy and stability of the spindle drive. The rolling bearing is used in auxiliary support, the front and rear radial bearing is used in master hydrostatic bearing. Thrust bearings are located on both sides of the former type of radial bearing to complete the selection of the spindle material and the design of the structural primary dimensions. It is meaningful to improve the specifications of CNC lathes, guide the design, generation and modification of the high precise CNC lathe and enhance static dynamic characteristics of the spindle and improve accuracy and stability of the machine tool processing. © (2012) Trans Tech Publications, Switzerland.


Li X.,Qiqihar CNC Equipment Corporation Ltd. | Li X.,Qiqihar University | Li X.,Harbin University of Science and Technology | Guo J.,Qiqihar University | And 5 more authors.
Zhenkong Kexue yu Jishu Xuebao/Journal of Vacuum Science and Technology | Year: 2011

A novel technique has been successfully developed to fabricate the micro heat pipe with sintered wick, recently widely used as highly efficient heat-sink in manufacturing microelectronic and optoelectronic chips. In the technique, the injected working fluid was first frozen; next, degassing was done by rapidly pumping the pressure down to below 110 Pa; and finally, the micro heat pipe was crimping sealed, followed by secondary degassing and crimping sealing. The field tests on industrial scale show that the micro heat pipe with sintered wick fabricated with the newly-developed technique outperforms that produced in the conventional method. For example, the pumping time is reduced by 2/3, and its thermal conductivity and quantity of the working fluid better satisfy the stringent requirements.

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