Materials Science Forum Vols. 697-698

Abstract: The Al-40Si alloy modified by 0.5 wt% Sr addition was heat treated using L₉(3⁴) orthogonal test. The mechanical properties were measured. The microstructures were analyzed using optical microscope. After heat treatment, the extension percentage increases more than twice. The eutectic matrix and primary Si phase are both refined. The primary Si phase is refined and homogeneously distributes in the matrix with the solution temperature and time increasing. However, the primary Si phase agglomerates each other with further increasing of the solution temperature and time. According to the microstructure, the optimal solution temperature and time are 500 °C and 14 hours, respectively. In addition, the optimal values for the hardness, tensile strength, and extension percentage are 35.4 HRC, 82.2 MPa, and 2.05 %, respectively.

Abstract: Molecular dynamics (MD) simulations were used to investigate the elastic properties of carbon nanotubes (CNTs). Displacements were loaded to CNTs on the tension deformation simulations. In order to better understand the relationship between Young’s modulus and the structure of the CNTs, different chiralities and diameters were involved. It is found that the Young’s modulus will be no more sensitive as in the single-walled carbon nanotubes (SWCNTs) with increasing walls. The tension deformation results also indicate that SWCNTs have better elastic property compared to multi-walled carbon nanotubes (MWCNTs).

Abstract: This thesis exploits a multichannel Gabor filters detection algorithm. Analysis filtering images from different orientations and scales, then fuses the multichannel data. Finally, a threshold iterative algorithm and mathematical morphology post-processing is used to achieve the fabric defect detection. The experiment selects five types of fabric defect image. Experimental results suggest that this algorithm can effectively identify blob-shaped, linear and planar defect and has well real-time character.

Abstract: This work screens electrode materials used in EDM and proposes some potential electrodes for future industrial applications. Traditional graphite, W, and Mo EDM electrodes have low TWR due to their high melting points; while, Zn, brass, and Cu often experience too much tool wear. As to some newly developed alloy and composite materials, their machining performances depend on not only their melting points but also their microstructures. Cu-W alloy has high wear resistance but it is susceptible to shape loss due to its internal porosity. By contrast, Cu-graphite, Cu-ZrB₂ and Cu-TiB₂ composites show good capabilities of removing material with little wear loss and therefore could be promising for future usages.

Abstract: Application on multi-platforms for a computer-aided fixture design (CAFD) system is significant. But now, relative less attention is focused on this direction. On above backgrounds, research was carried out on data construction, data description, data conversation as well as data parsing. In modular fixture system, components in the modular fixture base were described according to their CSG-based primitives. So, XML was used to represent the simple data because of its widely using on net and different operational systems. By developing interfaces between diverse CAD systems, the modular fixture system can be applied on heterogeneous environments and reinventing the wheel can be avoided.

Abstract: According to the design theory and method of complex product based on virtual prototype technology, with design characteristics of the hydraulic support, the system framework of the hydraulic support is established. The three-dimension (3-D) digital model of the hydraulic support virtual prototype conformed to the actual requirement is built. The static and dynamic analyses and simulation to the model are carried out. The research results show that the designed hydraulic support meets its actual work requirements.

Abstract: In order to make a 5-axis linkage horizontal machining center have better dynamic characteristics, considering the influence of joint surface, dynamic characteristic analysis is conducted to the machining tool. Based on finite element modal analysis results, the weak link is found and optimized. Through the finite element calculation and analysis, the structure rigidity obviously raises after optimization. This offers a new idea on how to improve the rigidity of complete machine of machining tool for later research.

Abstract: This paper analyzes the problems in traditional manufacturing and assembly, puts forward the Estimation Indication for Cost of Quality Losing in an optimization assembly which will be based on RFID. Though this assembly is a kind of selective one, the whole production will be according to the law of interchangeability. Take the hydrostatic bearing for example, and reduce the machining accuracy on the permitted assembling accuracy. At this condition, the quality of assembly will be guaranteed, but the cost and time of manufacturing will be decreased.

Abstract: In order to improve precision of grinding as well as accuracy of ball nose end mills, the Taguchi approach was adopted to figure out quasi-optimal parameter values of the XYZ axes drives and the controller for a five-axis tool grinder. Firstly, the backlash and pitch errors of the transmission system and rotational axes were measured via a laser interferometer, and these errors were compensated by setting compensation values on a human machine interface of the controller. Four control factors with three levels and an L9 orthogonal array were used in the experiments, and each experiment was repeated three times. Next, this parameter design was applied to obtain quasi-optimal values of the drives and the controller, and further a tool grinder was employed to grind five ball nose end mills to confirm the practicability. Finally, a tool measuring and inspection machine was utilized to measure the tool geometry of each end mill for the initial and optimal designs. Experimental results were shown to indicate the considerable improvement of the accuracy of the end mills and demonstrate the effectiveness of our proposed scheme.

Abstract: Comprehensive considered actual working conditions of cold rolling mill, a high precision shape detecting system of cold rolling strip was developed to meet industrial application. Consideration to both follow-up processing technology requirements, dynamic flatness standard curves could be formulated according to different rolling conditions and product specifications, and reliable shape datum were provided for close-loop shape control. This system was successfully used in Angang 1250 mm HC 6-high reversible cold rolling mill. Then the shape index and the quality stability of cold rolling strip were increased significantly, the errors between the calculated values and measured values of the total tension were less than 3%, the precision of shape detecting is 0.2 I and shape indices was within 6 I after the close-loop shape control was input.