Lamination of local electroplating film enables three-dimensional shape generation with a smooth surface and without heat affected layers. In this paper, we attempted a method to generate a three-dimensional shape by laminating electroplating with an electrolyte suction tool. In the equipment for local electroplating, the workpiece is fixed on an X-Y-Z stage, the plating solution is circulated in the electrolyte suction tool, and the copper plating is only performed on the selected area of workpiece surface under the tool tip. The electrolyte suction tool is mainly made of one tool electrode and one acrylic resin part that surrounds the tool electrode. Experiments for the lamination shaping were performed by increasing the reciprocal scanning number with the electrolyte suction tool, and the potentiality for three-dimensional shape generation was investigated and discussed. The results showed that the three-dimensional shape generation could be performed by scanning the electrolyte suction tool without scattering electrolyte. Also, the electrode volume wear ratio of Au electrode was similar to that of carbon fiber electrode, and the wear ratio was quite small and under 2 %. The price of carbon fiber is about one five hundredth compared with that of Au. Therefore, the utility of carbon fiber is very high in this research. In addition, the height of electrodeposit was increased in proportion to the number of round trip scanning of the electrolyte suction tool. However, it was found difficult to build a stable laminating height higher than 300 μm due to magnification of the protrusion.
Aiming at the problem of camshaft torsional oscillation caused by the torque of the engine camshaft spring, this paper carries out the research on the compensation of the elliptical pulley timing system for the torsional oscillation of the camshaft. In the quasi-static state, a dual overhead gasoline engine drive system model is established, and the increments of the tight and slack side belt lengths, the arc length of the pulley wrap angle and the direction angle of the pulley tangent point are studied. The relationship of the harmonic increments is determined. Based on the structure of fixed and automatic tensioners, a mathematical model of the elliptical eccentricity and the initial phase angle for compensating the harmonic oscillational torque of camshaft spring is proposed. The simulation results verify the correctness of the model. It is concluded that the elliptical eccentricity and the belt tension amplitude of the fixed tensioner are 50% smaller than the automatic tensioner, which reduces the dynamic excitation of the system. The tension distribution of the tight side and the slack side of the belt meshed with the elliptical pulley is different. The amplitude of the tension difference between the tight and side sides belts corresponding to the automatic tensioner is twice as large as that of the fixed tensioner. At the same time, the difference in tension will cause different elongation of the belt pitch between the tight and the slack sides, causing the meshing interference between the belt teeth and the elliptical pulley groove. Therefore, the tension distribution of the belt meshed with an ellipse is completely different from that of a circular pulley.
The application of semi-solid metal forming technology to the production of high-quality copper alloy parts has attracted more and more attention. Accordingly, as the key and foundation of semi-solid metal forming technology, it is particularly important to stably and efficiently prepare copper alloy semi-solid slurry with high quality. The purpose of this study was to innovatively optimize the process parameters by combining multiple optimization algorithms to stabilize the preparation of high-quality CuSn10P1 semi-solid slurry. And the self-developed Fully Enclosed Melt-Constrained Cooling Inclined Plate (FEMCIP) device was taken as the experimental equipment. Based on the optimization method of neural network genetic algorithm, the parameters of the preparation process of CuSn10P1 semi-solid slurry were optimized by combining orthogonal experimental design, grey correlation analysis method and Latin hypercube sampling, and using the finite element analysis software ProCAST and data analysis software MATLAB with the average shape factor as the evaluation index. By comparing with the slurry before optimization, numerical simulation results and experimental verification results, it was found that the semisolid slurry prepared by the crucible with preheating temperature of 990°C, cooling water flow rate of 680.517 L/h, cooling channel angle of 45°, inclined plate length of 300 mm and quasi-isothermal time of 42.715 s had the best quality. In this research, the semi-solid slurry of CuSn10P1 alloy with uniform microstructure and high roundness of solid particles was prepared by using this optimization method, which provided a new optimization strategy for the preparation of semi-solid metal slurry by using inclined plate type equipment.
Sheet metal forming is one of the important manufacturing technologies to produce metal parts. Tearing and wrinkling are major defects in sheet metal forming, and they should strongly be prevented for the high product quality. A constant blank holder force (BHF) is conventionally used for successful forming, but the variable blank holder force (VBHF) that the BHF varies during the forming process has attracted attention and has been recognized as one of the advanced manufacturing technologies. However, it is difficult to determine the VBHF trajectory for successful sheet forming without defects. In other words, a trial-and-error method is so widely used to determine the VBHF trajectory. In addition, blank shape also affects the product quality. In this paper, the blank shape and the sloped VBHF trajectory are optimized simultaneously. To determine them, a multi-objective optimization is performed. Numerical simulation in sheet metal forming is so intensive that sequential approximate optimization is adopted to determine them, and the Pareto-frontier is then identified. An automotive part provided from NUMISHEET2011 (BM3) is selected for the application of the proposed approach. The optimal blank shape and the optimal sloped VBHF trajectory is determined through the numerical simulation. It is found from the numerical result that the optimal blank shape minimizing earing without tearing and wrinkling can be obtained.
The aim of this paper is to study the modeling method of the geometric variations which occur at the successive set-ups of the machining process by relying on the small displacement torsor (SDT) and its transfer formula, and to develop the machining process evaluation method based on the limitation of functional tolerances. The proposed method firstly considers the machining process of the mechanical part as a mechanism mainly consisted of machine-tool, part-holders, machined part, and cutting tools; Then, the SDT parameters are employed to represent the geometrical variations of the part caused by the positioning errors and machining operations during successive machining set-ups; the SDT chains are used to model the deviation propagation between different set-ups. During the whole modeling, there are three kinds of torsors need to be defined which are the global SDT of the part-holder, machined part or machining operation relative to their respective nominal positions, the gap torsor between two contact surfaces, and the deviation torsor of the associated surface relative to their respective nominal positions on the part-holder, machined part or machining operation. After obtaining all SDT chains based on the process planning of the part, an evaluation method is developed to verify the effectiveness of machining process by cumulating the impacts of various manufacturing variations on the respect of functional tolerances. Finally, an example is given to illustrate how to use the proposed method to model the manufacturing variations and evaluate the machining process of the part in the field of CNC milling machining.