Advanced Materials Research Vols. 472-475

Abstract: The present Automatic Optical Inspection (AOI) technology can hardly satisfy online inspection requirements for large-scale high-speed, high-precision and high-sensitivity TFT-LCD. First, through studying the working principle of TFT-LCD Defect AOI System, the system architecture for mixed-parallel multi-core computer cluster is proposed to satisfy design requirements. Second, the study focuses on the software framework of AOI system and related key software technology. Finally, the fusion programming model for parallel image processing and its implementation strategy is proposed based on OpenMP, MPI, OpenCV, and Intel Integrated Performance Primitives (IPP).

Abstract: Through analyzing the shape of screw of oil extraction progressing cavity pump, the spiral surface equation of screw was established; and from the relative motion between formed milling cutter and screw, the basic profile equation of formed milling cutter was established with the method of non-instantaneous envelope. According to the actual use of formed milling cutter, aim at the problem of wear for formed milling cutter, established profile equation of front cutting edge and constant back cutting edge, and finally to get a complete profile equation of formed milling cutter. The correctness of milling cutter profile is ensured by interference checking for profile equation of formed milling cutter. The profile equation of formed milling cutter provides a theoretical foundation for the design and manufacture, and it would have great significance to the actual production.

Abstract: This paper deals with the roughness forming mechanics of aspheric surface, and based on the subsequent abrasive blade theory, which will form the final ground surface, the mathematical model of maximal valley height of ground surface during aspheric parallel grinding was established. Through simulation study, the influences of grain size, the speed of wheel and workpieces on the aspheric surface roughness were analyzed, and furthermore, through test, the proportional relation between the maximal valley height and the roughness was found.

Abstract: The paper based on Mitsubishi M70 NC system, firstly, the theoretical analysis of scroll-type lines and the processing methods have been made, and then focused on the study of the relationship between the C-axis, the X-axis with NC feed rate .Finally, Mitsubishi M70 CNC was used on the fine milling of the scroll plate. The experiment has showed that the result is fine.

Abstract: The manufacturing of silicon wafers in particular involves numerous processes such as grinding, lapping, and polishing of large diameter wafers employing expensive equipment in order to produce the required optical quality and damage-free surfaces. In the finishing of thin silicon chips for making IC chips especially, it is difficult to lap and/polish the substrate and obtain low surface integrity, surface finish and at the same time generate flat planar surfaces. This paper presents the development of a low cost lapping process, the process tried out on thin silicon chips that generated fracture-free with mirror-like surfaces of low roughness values and reasonably high degree of flatness.

Abstract: In order to achieve the controllability of the abrasive arrangement on the working surface of grinding wheel,a new kind of the superabrasive grinding wheel, which has defined abrasive grain cluster pattern, has been designed based on the phyllotaxis theory of biology, and fabricated with UV lithography method and electroplating technology. The analytical results indicate that the phyllotactic parameters influence on the abrasive arrangement configuration on the work surface of the superabrasive grinding wheel, so as to improve grinding performance of the grinding wheel, increasing the diameter of phyllotactic abrasive grain cluster and decreasing phyllotactic coefficient can increases the abrasive grain density of the surperabrasive grinding wheel surface. Electroplating experimental results show that the reasonable electroplating processes can reduce the faults of defined abrasive arrangement on the superabrasive grinding wheel surface.

Abstract: The grinding precision and the surface characteristics of the engineering ceramic are hard to control because of the hardness and brittleness. In order to grind the engineering ceramic under ductile mode, it is necessary to reduce the displacement of the grinding machine for the limitation of its stiffness to keep the grinding parameters in micro scale. A three-degree-of-freedom parallel workpiece table for ceramic grinding is developed to compensate the deformation of grinding machine caused by grinding force during grinding process. Based on the principle of negative stiffness, the workpiece table can generate a displacement which is reverse to the loading direction to compensate the deformation of the grinding machine. The developed precise workpiece table is a three degree of freedom negative stiffness controllable parallel mechanism composed of three piezoelectric actuators and a flexible parallel mechanism. Then the characteristics, such as kinematics and workspace, of the workpiece table are studied.

Abstract: Offline programming can generate programs with optimized structures and clear layers, realizing parametric programming. It is able to achieve almost all kinds of measurement objects. Subroutine can be used for improving programming efficiency. This paper introduces the application of offline programming through instances.

Abstract: Error compensation is an effective method to improve the machining accuracy of NC machine tool. A laser tracker is used to rapidly and accurately detect the geometric error of NC machine tool in the paper. The machine tool is controlled to move on the preset path in the space, and a laser tracker is used to measure the motion trajectory of the machine tool. Each geometric error can be identified by error separation. Based on the error model of 3-axis machine tool, error compensation can be carried out by modifying the machining process (G code). Results of experiment show that, this measurement method is feasible, and modifying the G code for error compensation is also effective.

Abstract: Restrictors are one of core parts in aerostatic systems. A special multi-microchannel aerostatic restrictor is designed and developed, and the air film thickness is measured by the capacitive measuring method. The mathematical model of capacitance and air film thickness is carried out, capacitances of specific air film thickness are calculated, air film thickness of the multi-microchannel aerostatic restrictor with the overall diameter is measured, and error sources processed and analyzed. Results illustrate that errors between the theoretical calculations and the experimental data are less than 13%, this proves the correctness of the mathematical model as well as the effectiveness of the capacitive measuring method applying for the air film thickness measurement of the aerostatic systems.