Key Engineering Materials Vols. 426-427

Abstract: In this paper, according to the requirements of some cam component in rotary press, cubic NURBS spline is used to generate the contour of cam after calculating every control point on the basis of movement requirement of driven part. And software ADAMS is used to verify the calculation result. Results show this method is an effective way for manufacturers of rotary press to generate cam contour, which can improve the performance of cam mechanism and save much time.

Abstract: This paper proposed a new method of automated eliminating bubbles based on vision sense technology because detection and elimination of bubbles of injection materials is key factor which influences the quality of products and hinders realization of full automatic control for the vacuum casting. This method uses vision sensor to replace artificial visual measurement, and adopts processing of the bubbles images to judge the effect of eliminating bubbles instead of experiences of operators. This paper developed a bubbles monitoring control system to realize the automated eliminating bubbles method. The system adopts two-level distributed structure which is consisted of host and slave computers. The slave computer is composed of image acquisition module, controller module and execution module. It is responsible for controlling operation devices to finish vacuum casting. The host computer is responsible for supervisory control which includes human-machine interface module, camera control module and images analysis and processing module. The function of every module is described in detail. The operator is just needed to set relative parameters, and then the system will implement automatically. In a word, the controlling system based on this new method possesses some advantages such as high precision, efficiency and flexibility.

Abstract: Functional manufacturing technologies are becoming more and more important to the manufacturing industry and research. As promising categories of functional manufacturing, micro and nano manufacturing have received steadily growing interests in recent years. In this paper, as typical examples to demonstrate micro and nano manufacturing, our work on microthruster, nano energetic material, and micro/nano initiator is presented. Microspacecraft is one application of microsystem in space. In a microspacecraft, a micropropulsion system is required for station keeping, attitude control, and orbit adjust. New silicon and ceramic microthrusters are described. Energetic materials including propellants, explosives, and pyrotechnics have found diverse applications. Nano energetic materials (nEMs) have improved performances in energy release, ignition, and mechanical properties compared to their bulk/micro counterparts. A novel nano Al and CuO nanowire based nEM is discussed. Electro-explosive devices (EEDs) activated by electrical energy are used to initiate an explosive, burning, electrical, or mechanical train. EEDs have found numerous applications in triggering the inflation of airbags in automobiles, micropropulsion, and arm fire/safe devices for ordnance systems. An innovative EED is developed by integrating Al/CuO based nEM with a Au/Pt/Cr micro heater on a substrate.

Abstract: High quality optical grade thick diamond film wafers with different thickness are prepared by high power DC arc plasma jet CVD (DCPJ CVD) method using a CH4/Ar/H2 gas mixture. Three different powers, 13.65, 15.40 and 17.94kW, were employed during the investigation. The aim was to investigate the effect of these powers on the deposition of thick diamond film. The controlled system was discussed together. The results show that the average diamond grain size and growth rate increase with input plasma power, but a further increase in input power, diamond thick-film defects and amorphous carbon content increased.

Abstract: In order to improve information asymmetry in construction supply chain and keep effective information among parties involved sharing seamlessly, current narrow sense understanding of information sharing in construction industry is summarized firstly; then broaden content and essence of information sharing in construction supply chain is pointed out, that is not only information sharing which can be improved by information technology included, but some asymmetric information which caused by different parties own interest also included in sharing scope. Information sharing is process of making information symmetrical to each party. Conclusion is given that information sharing is basis for adding value to whole construction supply chain under the condition of risk & profit sharing.

Abstract: Considering the development of cooperative design and internet-based manufacturing and in order to manage the manufacturing process more efficiently, a unit of remote intelligent fault-diagnosis based on Bayesian Networks was designed and a software based on internet was realized. The establishment of such system will enable efficient cooperation between CNC machine tools and users as well as maintainers.

Abstract: Bubbles in the manufacturing process are common. The bubbles often lead to the decrease of the product’s surface quality and internal performance. This paper summarized the published researches and applications of the detection and processing for bubble images, of which the advantages and disadvantages were also presented. Based on the above mentioned results, this paper then proposed a new bubble image processing algorithm for vacuum casting process, in which the characteristics of the bubbles in vacuum casting process and the problems possibly caused in detail were analyzed. According to the characteristics of bubbles in vacuum casting process, an image processing algorithms was designed using Matlab. The simulation result showed the efficiency of the proposed algorithm.

Abstract: Due to the high cost-effectiveness, extra flexibility, and short production cycle, laser direct writing system as a kind of maskless lithography technology has been widely used in the fields of micro-nano-manufacturing. The working principle of the parallel laser direct writing system based on DMD(Digital Micromirror Device) is introduced. A novel negative photoresist -- dry film photoresist is adopted into the study of deep etching for the fabrication of the micro mold. The experimental results show that: the whole process is convenient, efficient and flexible; the precision of the 2-D patterning and the depth of etching is reliable.

Abstract: An implementation methodology is proposed to serve a system for the network-based design and GM (Green Manufacturing), and the detailed design process of the system is introduced, which would be universally applicable for mechanical product design for green manufacturing. To realize the remote product data management, the dreamweaver software and FTP functions are used, and some new programs are developed to building the parts library based on UG NX development platform. However, the client database management has been realized by using IIS and ODBC functions. Eventually a prototype system is developed to accomplish concurrent design for green manufacturing.

Abstract: In the paper, forward extrusion-equal channel angular extrusion (FE-ECAE), which is new strain-induced melt activation (SIMA) method, is introduced in making semi-solid billet of 7A04 alloy. The principle of the method is that by using FE-ECAE as strain induced step and semi-solid isothermal treatment as melt activation step. The results show that semi-solid billet with highly spheroidal and homogeneous refined grains can be prepared by FE-ECAE method. The equivalent strain in FE-ECAE before reheating has a great influence on its microstructural evolution. Grain size decreases and its shape also approaches to sphericity with increasing equivalent strain. The main mechanism of the initial semi-solid grains coarsening was coalescence. With the prolongation of isothermal holding time, the grains grew up and spheroidized, in which the mean diameter of grain and liquid volume fraction increased. In the meantime, the higher the reheating temperature, the faster the grain grew and spheroidized. Subsequently, the main mechanism of grains coarsening was Ostwald ripening. The suitable reheating temperature of 7A04 alloy was 610°C.