Applied Mechanics and Materials Vol. 607

Abstract: Workshop is gathered place and exchange centre of product manufacturing process information (PMPI), which is divided by enterprise heterogeneous systems. This led to the integration and sharing difficulty of PMPI and constrains the information system application in workshop, like MES. To solve this problem an information integration method based on semantic BOM was proposed. Firstly, a global ontology model USBOM of PMPI was constructed which given the unified semantic description of PMPI. Based on USBOM a PMPI integration framework was proposed. Finally, a workshop product manufacturing monitoring system was used as an example to verify the feasibility of this approach.

Abstract: To solve the difficulty of equipment testability verification experiment sample selection, a sample selection method of testability verification experiment was presented. The failure-test dependency matrix and its extended matrix, failure modes function equivalence set and failure modes test equivalence set were analyzed, on the basis, failure modes sample equivalence set was proposed. Meanwhile, importance characteristic was analyzed and maximum entropy was solved, and the sample selection method was presented, its process was obtained. Moreover, the method was comparatively analyzed with actual methods in the experiment. The results show that application the method in paper, can reduce sample number, save test expenses, and meet the test requirement of adequacy, so the method in paper is proved effective and feasible.

Abstract: In this paper, the optimal assembly sequence is considered as precedence graph which reduces the complexity of the problem, and an exact algorithm named task-oriented enumeration is proposed to solve the single-model stochastic assembly line balancing problems of type-1. The results show the proposed algorithm can solve the single-model stochastic assembly line balancing problems of type-1.

Abstract: Soda lime glass is a very important material in diverse manufacturing industries, including automotive, electronics, and aerospace. In these applications, the glass surface needs to be defect free and without impurities. However, the machining of glass is difficult due to its inherent brittleness which leads to brittle fracture and easy crack propagation. This research investigates the high speed micro-end milling of soda lime glass in order to attain ductile regime machining. It has been found by other researchers that ductile mode machining can avoid brittle fracture and sub-surface cracks. Also, in this study, a special air delivery nozzle is used to blow away the resultant chips and keep the machined surface clean. To accomplish this, Design Expert software and a commercial NC end mill were used to design and perform the machining runs, respectively. The surface roughness of the resultant surfaces was later analyzed with a surface profilometer. Microphotographs of the machined surfaces were also taken in order to see how effective the air blowing method is. The results of surface roughness measurements were then used to develop a quadratic empirical model for surface finish prediction. Finally, desirability function and genetic algorithms were used to predict the best combination of cutting parameters needed to obtain the lowest surface roughness. The predictions were later tested by experiments. The results demonstrate that this type of machining is viable and the roughness obtained is very low at 0.049 μm.

Abstract: In the application of sprays produced by an atomizer, spray angle is one of key performance parameters. A larger spray angle is often required in providing a better spray dispersion. Swirl effervescent atomizer is one of the existing atomizers with the capability to produce a large spray angle. The formation of spray angle from this atomizer however is hardly understood. A newly-designed swirl effervescent atomizer was developed and tested with different swirl-generating vane angle in order to understand the swirl intensity effect on the spray angle. Experiments were carried out based on a cold flow test approach using water as the working fluid and nitrogen gas as the atomizing agent. High-speed shadowgraph technique was deployed to record the resultant sprays produced. Video recordings, acquired using a high-speed video camera, were converted to a sequence of images for further analysis using an image processing software. It was found that the spray angle increases with the swirl-generating vane angle. Specifically, the spray angle shows an abrupt increase for the case of swirl-generating vane angle changing from 30° to 45° but visualizes only a gradual increase in the case of swirl-generating vane angle changing from 45° to 60°.

Abstract: This study aims to find a solution to improve the formability in a deep drawing process. For this purpose drawbeads were used to avoid wrinkles and ruptures. The finite element method was applied to simulate the 3D metal forming process using a die and drawbead. The drawbead amount, position, size and form were studied for their affects on the formability. 3 drawbead patterns with 3 different heights were examined. The simulation was performed for each drawbead pattern and each drawbead geometrical parameter and the failure elements were counted. The best pattern chosen was the pattern that resulted in the least failure elements.

Abstract: In view of complex and fuzziness of geological adaptive cutterhead selection for earth pressure balance (EPB) shield, a cutterhead selection method based on BP neural network is put forward. Considering the structure characteristics of EPB shield cutterhead, typical cutterhead types are classified and summarized based on cutterhead topology structure and number of spokes. After analyzing the determinants of cutterhead selection, one-to-many mapping relation between cutterhead type and geological parameters is put forward, and then core geologic parameters related to cutterhead selection are concluded. The feasibility of using neural network method to choose the cutterhead type is analyzed, and a BP neural network training model for cutterhead selection is set up and tested in testing sample data. The result shows that the selected cutterhead and the construction cutterhead are basically consistent. The feasibility of this method is proved and it can be theoretical basis for the cutterhead structure design which will improve scientific of cutterhead selection.

Abstract: Sheet dieless digital forming is a new sheet metal dieless forming technology. This paper introduced the fundamentals of the Sheet dieless digital forming process. Based on the principle of “layered manufacture” in rapid prototype technology, this process resolves the intricate three-dimensional geometry information of the workpiece into a series of two-dimensional data, which can be used by an NC system to control a forming tool to make a curvilinear movement over the raw sheet metal layer by layer until the component wanted is formed. This paper introduced the Sheet dieless digital forming system and metal digital forming technology.

Abstract:     A number of laser-MIG hybrid welding experiments were carried out for 4 mm thickness Ti-70 alloy by the single channel single full penetration welding procedure, and obtained the excellent surface formation welding joints with no internal defects. Experimental results show that some bulky columnar crystals form in the Ti-70 welding seam under the hybrid heat source, mainly composed by α′ phase martensite and spiculate α microstructure, and while the Ti-70 alloy welding joints have good comprehensive mechanical properties and can meet the needs of practical engineering.

Abstract: Based on the theoretical study in our previous work, a novel thermal assisted ultrasonic bonding method for polymer Micro/nanoElectro-Mechanical Systems (M/NEMS) has been demonstrated. Bonding experiments of PMMA microfluidic chips with micro-channel of 80 μm in depth and width were conducted. The result shows numerous superiorities of this method including high bonding strength (0.95 MPa), low dimension loss (0.8% in depth and 0.3% in width, respectively) and short bonding duration.