Abstract: In this paper, the application range and the characteristics of the stacked injection molding were introduced. The latest development and present application of the stacked injection molding were also presented. Furthermore, the routine problems of the stacked mold during the injection molding process are analyzed, and some improvements of the stacked mold structure are proposed.
Abstract: In this paper, a method of fabricating single crystal silicon microstructures on oriented silicon wafer is developed. The relationship of the (111) planes on silicon silicon wafer is analyzed based on the crystal lattice of the silicon, the method of judging these (111) planes is given. An anisotropy wet-etching experiment is done to verify the etching characteristics of silicon. The process of fabricating three dimension structures on silicon wafer is then given out and some basic MEMS structures such as cantilever beams, doubly-clamped beams are fabricated. With this method, it is easy to define the shape and thickness of the microstructure and the process is not complicate. Moreover, the structures made in this way have higher structural precision and mechanical strength.
Abstract: WS2 soft coatings were deposited by medium-frequency magnetron sputtering, multi-arc ion plating and ion beam assisted deposition technique on the YT15 cemented carbide substrates. The influence of the substrate bias voltage on the coating properties has been studied. The coatings exhibited a dense and fine grained structure. WS2 soft coatings with substrate bias voltage of -100 V revealed a better coating properties than other four samples, as the best crystallization of (002) preferred crystal orientation of Ⅱ texture, the most smooth and uniform microstructure of the coating, the largest critical load of 43.25 N and the largest coating thickness of 1.5 μm. But the microhardness of sample S1 was only 515.4 Hv. The critical load and the thickness of WS2 coatings decreased firstly, then increased, and finally reduced with the increasement of substrate bias voltage. And the microhardness of the coatings decreased firstly, then increased, and decreased, finally increased with the increasement of substrate bias voltage.
Abstract: Computational models of deformation and friction work were established by dividing contact arc between strip and work roll into two sliding regions, two braking regions and one stagnating region. A two dimensional temperature field model of work roll was established by finite difference method according to practical boundary conditions. Simulation results show that with the increase of rolling pass, deformation work reduced while friction work increased, except that deformation and friction works at the last pass were the least. The computed rolling forces and work roll surface temperatures agree well with measured values collected from a hot strip mill.
Abstract: In this paper, sets of experiments are carried out on the difficult-to-machine nickel-based superalloy based on the principle of micro electrochemical milling with nanosecond pulse current. First, an experimental system for meeting the requirements of the EMM process is established. Second, sets of experiments are carried out to investigate the influence of some of the predominant electrochemical process parameters, such as machining voltage, pulse on time, and electrolyte concentration, on machining accuracy. Finally, using the optimization parameters, a series of 2D and 3D micro structures have been successfully obtained.
Abstract: In this paper, the application range and the characteristics of the Bi-color injection mold were introduced. The latest development and present application of the Bi-color injection mold were also presented. Then, the routine problems of Bi-color mold are analysed, and some improvement methods of Bi-color mold are discussed in the end.
Abstract: A multilayer masking technique was presented aiming at the requirements of deep isotropic silicon wet etching. Because the processing time of deep etching is relatively long and etching rate is high, it is very hard to achieve satisfying etching result by using conventional photoresist or metal single layer mask. Thus multilayer mask consisting of photoresist and metal layers is fabricated to exert respective advantages and avoid disadvantages. Based on its excellent chemical and thermal stabilities and high viscosity, Su-8 was selected as the material of photoresist layer. The metal layer was fabricated by chromium because it could alleviate the undercut problem in great extent. Results of etching experiment indicated that no obvious defect of pinhole or crack was found on this multilayer mask after etching to the depth of about 300μm. Thus it is undoubted this masking technology is capable for deep silicon wet etching.
Abstract: Aimed at relieve the human labor intensity, boost work efficiency and lower production costs, a hydraulic mulberry trimmer is developed, which is introduced in this article. Specifically, the cutting principles and motion parameters are analyzed in the processing of trimming, and then the feasibility of the selective parameters are verified though the cutting experiments on mulberry shoots and the calculation of the cutting force.
Abstract: Based on CFD simulations and experimental research, this paper studied the mach of impeller outlet and diffuser inlet in stamping and welding centrifugal pump. The influence of area ratio Y of impeller outlet to diffuser inlet on pump internal flow characteristics and performance was studied. Five different area ratio pump models were analyzed. The results indicate that as the area ratio Y= F3/F2 increase, the velocity of fluid in diffuser inlet decreases continuously, the average static pressure of diffuser outlet increases, and the head and efficiency of the pump are risen. When the area ratio increases from Y=1.48 to Y=3.49, the head increases about 3.0% and the efficiency about 2.0%.
Abstract: According to the request of equipment for high-power belt conveyor, the controlled soft start equipment based on PLC was designed. The soft start process was analyzed and the idea velocity and acceleration curve of start process and the driving circuit of electro-hydraulic proportional valve were given, also the control strategy was designed. Through experiments test, the electrical control system designed in this article is able to control accurately mechanical transmission and hydraulic device and can finish the soft start function for belt conveyor.