Advanced Materials Research Vols. 472-475

Abstract: A representation method for line edge roughness (LER) parameters based on wavelet-analysis is proposed. Multi-resolution analysis is processed on both spatial features and frequency features of line edge. Different feature details are achieved with different analysis resolution. The features of line edge are able to be represented well by wavelet analysis. And an extraction method for contour line of LER is designed based on wavelet baseline. The experimental results show that more details of LER features are obtained by multi-resolution wavelet analysis. The method is feasible to estimate the nano-scale LER. Therefore, it is possible to reduce the processing errors of nano-scale manufacturing line.

Abstract: It analyses deeply the diffrence between micro cutting and conventional machine cutting from the mechanism of cutting surface formation in this paper, and building the micro cutting model , then analyses friction mechanism of micro cutting processing introduce a new micro friction model, this paper discusses interface micro friction characteristics in the process of micro cutting.

Abstract: Based on the analysis of electrical discharge process characteristics, the principle of achieving deposition process and removal process using micro EDM is proposed. By controlling the tool electrode wear in one micro EDM system, it is easy to achieve the different machining type of deposition or removal process. Centering on the problem of tool electrode wear, the process conditions of the deposition and removal including machining polarity, machining dielectric medium, discharge parameters and the tool electrode rotation are researched detailedly. Results show that under the discharge phenomena between electrodes, metal material can be deposited to form micro structures, and the transfer strategy from deposition to removal process can be controlled easily. The machining procedure for fabrication of micro structures based on depostion and removal process are put forward. And finally, some examles with well shape and dimension accuracy are given to validate the processing ability for micro machining.

Abstract: Cadmium molybdate (CdMoO4) nanoparticles, cube-like crystallites and octahedral microparticles have been successfully synthesized by a molten salt method at 270°C. The structure, morphology and luminescent property of the resultant powders were characterized by X-ray diffraction (XRD), transmission electron microcopy (TEM), scanning electron microcopy (SEM), and photoluminescence (PL), respectively. The resultant samples are a pure phase of CdMoO4 and without any impurities. PL spectra results show that the optical properties of CdMoO4 particles are strongly relied on their morphologies.

Abstract: The small batch control chart was advanced in the modern production in order to control the detection process more effectively. The Q control chart got certain applications for the characteristics of its own, but the effect is not outstanding in the beginning of detection. In this paper a method that combined it with VSI was discussed and applied to an example, and was found it is a more accurate and effective method.

Abstract: This paper studies a just-in-time job-shop scheduling problem (JITJSSP) in which each operation has an earliness cost or a tardiness cost if it is completed before or after its due date and the objective function is to minimize the total earliness and tardiness costs of all operations. In order to solve this problem, an improved genetic algorithm (IGA) is introduced in this paper. IGA utilizes an operation-based scheme to represent schedules as chromosomes. Then, each chromosome is processed through a three-stage mechanism. Firstly, the semi-active decoding process is employed to expand the search space of solutions and guarantee comprehensive solutions. Secondly, the greedy insertion mechanism for tardy operations is executed to move the tardy operations left to the appropriate idle time to reduce the tardiness costs. Finally, the greedy insertion mechanism for early operations is proposed to shift the early operations right to the suitable idle time to decrease the earliness costs. After the maximum number of generations is reached, IGA continues with selection, crossover and mutation. The experimental results finally show that most of solutions on the benchmarks are improved by our algorithm.

Abstract: We make use of embedded BASIC Stamp 2 (BS2) microchip controller to design with Hopfield neural network (HNN) as the foundation of sample training, which applies for a soldering platform of mechanical vision and accomplishes PCB soldering positioning technology. The system is verified by Matlab and Simulink to set up the simulation of PCB image soldering positioning. The experiment is proved to improve the traditional low efficiency of PCB soldering technology, to achieve the feasibility of PCB image positioning and to promote the soldering quality.

Abstract: An experimental device of KOH solutions jet-assisted laser etching is designed, Laser-chemical combined etching technology is combined with the Medium-jet erosion processing ,and the influence on the etching capacity and cross section quality of material sample of laser processing parameters,jet processing parameters are studied. The results show that the laser processing parameters and jet processing have a decisive impact on the quality of the workpiece, the composite processing technology can remove most of melting slag which are produced by the laser processing, the surface roughness are effectively reduced. The blind holes of the machined materials have the regular shape.

Abstract: Laser shock forming (LSF) is a novel plastic forming process which utilizes high-pressure plasma to deform thin metals to 3D configurations. The plastic response of a circular plate in laser shock bulging forming was theoretically studied. A simplified shock pressure model was established and then an analytical model was proposed to calculate the deflection. The results show that the deflection increases with increasing pulse energy and the deformation profiles calculated by the analytical model agree well with those of experiment.

Abstract: Those ultimate reasons of over-cladding and under-cladding are indicated through analyzing between the existing parallel scan mode and the characteristic of metal laser deposition shaping. A kind of scan path generating algorithm is presented based on only parallel filling scan, firstly, increasing scan line based on recognizing characteristic points is adopted which generate the scan filling line according to the set scan space; then, scan path is generated through grouping and optimizing to connect filling lines based on judging the distance of between the end point of last vector and the start point of next vector. Practical application shows that the scan path can effectively enhance the flatness of shaping layer and the fabrication quality, ensure to shape successfully.