Advanced Materials Research Vol. 797

Abstract: In this study, measurable thickness range was improved by re-customized components of the thickness measurement system using the method of Fabry-Perot interference signature analyzing. A Fourier transform near infrared (FT-NIR) spectrometer with indium gallium arsenide was used in the developed system. As a result of the sensitiveness in the whole near infrared band and high spectral resolution united with high signal noise ratio of the FT-NIR spectrometer, the maximum measurable thickness is improved to 88μm while sub-micron order of the minimum measurable thickness is also improved.

Abstract: While measurement accuracy can be increased through continuously improving instrument precision, certain measurement errors can be eliminated via data processing using properly devised processing algorithms. Multi-point roundness error separation methods that are the subjects of study in this paper are reviewed, in particularly, three-point method and other multi-point methods that are based on three-point roundness error separation method, such as two-point method, mixed method and four-point method are summarized. Finally a comparison between each separation methods mentioned in this paper is made. Our views of future development trend in multi-point roundness error separation methods are presented.

Abstract: Larger diameter wafers are used to decrease the cost of IC manufacturing and the wafer thickness is decreasing for form factor and thermal power dissipation considerations. The larger wafer requires a large scanning area to inspect the warp, and warp measurement of large and thin silicon wafers is greatly affected by the gravity-induced deflection. In this paper the gravity-induced deflection was calculated using finite element method by supporting the wafer horizontally with three steel balls. A laser displacement sensor based on triangulation principle was used to measure the warp and an air bearing stage was developed to achieve high straightness. The shape of the wafer was obtained using the silicon wafer warp measuring equipment.

Abstract: Based on the iso-scallop height NC machining method, the topic researched on the use of it in the NC grinding. According to the convexity and concavity rotating workpiece, calculating the feeding line while using cylindrical grinding wheel and wheel grinding wheel, and dispersing the generating line of the gyro-rotor. At last, with a special rotating workpiece for example, achieving the most reasonable grinding parameters, tool path strategies and the pulse control strategies according to the radius of curvature, realizing the promotion and command of the grinding precision.

Abstract: The mathematical modeling of the cutting tools is an important aspect for the design and manufacturing engineers from the viewpoint of shape realization. Taper mill is composed of side and end edges. In order to make each patch closely combined, the groove section is designed by considering the relation among tapered radius, groove depth and radius of inner land. Through translation and rotation of shape curve, the side flute and end flute model can be established. These models can be rendered in three dimensional software according to parametric design of taper end mills. And this methodology can be easily extended to design, manufacture other tools.

Abstract: In order to perform adaptability comprehensive evaluation of auto assembly machine product platform for small shaft and sleeve subassemblies, with product family-oriented design, more reasonably and effectively, a fuzzy comprehensive evaluation method based on fuzzy analytic hierarchy process (FAHP) is discussed in this paper. And the hierarchical structure of comprehensive evaluation index system, the alternative set and the comprehensive evaluation model of product platform are established through this method, thus obtaining a satisfaction value, which realizes the change from qualitative evaluation to quantitative evaluation for product platform evaluation. The result shows that the method has a strong feasibility and operability.

Abstract: As for the deficiency by using manual hammer for modal testing, an electronic impact hammer testing device is developed in this paper. The developed electronic impact hammer consists of workbench, controller, trigger, switching power supply, and actuator, etc. According to the electromagnetic theory, by controlling traction electromagnet on/off to make the traction force drive the impact hammer, the hammer impacting on the testing object can be realized. By means of controlling the contact time between the impact hammer and the object to be impacted, an ideal force pulse signal can be got. The developed electronic impact hammer has the advantages of repeatability and regulatory. Face milling cutter tip point frequency response functions is tested by using the device in this paper. The frequency response curve and the modal parameters for the face milling cutter are obtained.

Abstract: There are lots of defects in the drilling process of CFRP, such as splitting, etc, which may affect the assembly quality of the composite materials. Through the analysis of the drilling mechanism of CFRP, and with the help of the correlation experiments of drilling tools, the effects of machining parameters and machining tools on hole quality are studied, the optimal selection method of the drilling tools for CFRP and the selection principle of technical parameters under different machining conditions are also discussed. And the tools geometry affects the hole-machining quality of CFRP materials directly, which should be chosen in accordance with the hole-machining method.

Abstract: Superalloys are widely used in the aeronautic and astronautic industries owing to their excellent properties in aspects of high-temperature strength, heat stability and thermal fatigue resistance. However, the severe loading of grinding wheel and the poor integrity of grinding surface usually become the problem in grinding of superalloys with conventional grinding wheels. In this paper an experimental study was carried out to investigate the grinding characteristics of superalloys with microcrystalline alumina abrasive wheel. The roughness of grinding surface was tested, on which the effects of the grinding parameters were analyzed. Study results indicated that low loading of grinding wheel and high quality of grinding surface (Ra 0.2 μm) were obtained. The grinding parameters were optimized based on the experiment results.

Abstract: In the NC machine tools for automatic mass production processing lines, it is demanded that high stable machining accuracy is maintained for a long time. The main factor of deterioration in machining accuracy depends on the thermal deformation of machine tool, and the measures are one of the most important issues in the machine tool design. The thermal deformation is practically estimated by the temperature changing state of machine tools based on obtained data of their thermal deformation chracteristics. The estimation accuracy of thermal deformation depends on the thermometry points of machine tool greatly. This study describes an approach to the most suitable thermometry points in machine tool to determine the effective thermal deformation measures experimentally. As a result, the existence of points where the temperature of components changed with relation to thermal deformation very closely was confirmed.