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RISS 인기검색어
- 검색키워드
- 저자 : Huajie Mao (검색결과 4 건)
- 무료
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Wei Guo,Bo He,Huajie Mao,Mengying Zhang,Lin Hua,Zhenghua Meng 한국섬유공학회 2019 Fibers and polymers Vol.20 No.7
A combined in-mold decoration and microcellular foaming injection molding process (IMD/Mucell) is proposedto improve the surface quality of foamed parts. Through theoretical inference, the mathematical models of temperature field,velocity profile and forces on bubble were established with combining traditional mathematical models and the different heattransfer coefficient of the mold inner surface. The effects of the non-isothermal mold on the bubble structure and formingprocess of inter bubble were investigated with experiments and numerical simulation. Results showed that the criticalpressure of the cavity existed in the melt filling and bubble expanding stage, and it affected the cells structure obviously at thefilling stage. The lift force took the bubbles to the film side based on the velocity profile of viscous fluid, and maximal bubblewas closer to the transition layer with film due to higher temperature. In the combined process, the evolution rule ofsuperficial bubbles was analyzed, and results showed that the surface quality was improved in the film side.
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Optimum Blank Design of Thick-Plate Metal Forming without Blank Holder
Jian Lan,Mianli Zhang,Huajie Mao,Maosheng Shu,Lin Hua 한국소성가공학회 2010 기타자료 Vol.2010 No.6
Many blank design methods are used in sheet metal forming industry, but most of them originated from applications of thin sheet metal forming with blank holder. There are few researches on blank design methods of thick-plate metal forming without blank holder, which process has two characteristics: workpiece thinning locally and severely, workpiece inside surface not contacting with top punch because of local bulk deforming. An optimum blank design method is proposed in this paper for the thick-plate metal forming without blank holder. This method consists of two stages: the initial blank design stage and the blank optimization stage. The first stage is to obtain initial blank shape using Inverse Finite Element Approach (IFEA) from the middle-thick layer of 3D model of target part. In the second stage, firstly, simulate and obtain deformed workpiece by forward finite element analysis; then calculate the shape error between deformed workpiece and target part, and the indicator △ of optimization procedure; finally, correct the blank shape by the feedback of shape error until the indicator △ is smaller than tolerance. In order to verify the proposed method, a reverse arm bracket is investigated.
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Prediction of warpage in plastic injection molding based on design of experiments
Wei Guo,Lin Hua,Huajie Mao,Zhenghua Meng 대한기계학회 2012 JOURNAL OF MECHANICAL SCIENCE AND TECHNOLOGY Vol.26 No.4
In terms of injection processing parameters, a mathematical model for prediction of warpage was formulated based on design of experiments (DOE). First, the five most influential parameters were screened by using fractional factorial design (FFD): melt temperature,coolant temperature, injection time, V/P switch over and mold temperature. Second, considering the other four principal processing parameters except the melt temperature, the predicting mathematical model was founded by using central composite design (CCD) of experiments and FE simulation. Finally, the results of statistical analysis were collected from software Moldflow. The results suggested that the mathematical model can be used to predict warpage with adequate accuracy. Hence, it indicated that corrective and iterative design steps can be initiated and implemented for better quality of products without resorting to physical trials in plastics injection mold by using this predicting mathematical model.
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Research on the effect of ultrasonic vibration on the roll-over during the fine blanking process
Yanxiong Liu,Tao Cheng,Lin Hua,Huajie Mao 대한기계학회 2017 JOURNAL OF MECHANICAL SCIENCE AND TECHNOLOGY Vol.31 No.2
Fine blanking process as an advanced sheet metal cutting process has been widely used in industry. However, the roll-over of the parts fabricated by this process weakens the performance. For some parts, i.e. gear, the size of the roll-over should be very small in some situation. Therefore, a lot of efforts have been made to reduce the roll-over size or even eliminate the roll-over. Since the high frequency vibration can greatly change the metal flow, the ultrasonic vibration was applied into the fine blanking process to eliminate the roll-over in this paper. A finite element model was created to investigate the roll-over forming mechanism in the ultrasonic vibration assisted fine blanking process. The forming force, metal flow and mean stress were analyzed and compared with the conventional fine blanking process, and the roll-over size variation mechanism of the ultrasonic vibration assisted fine blanking process was revealed. An experiment of ultrasonic vibration assisted fine blanking has been carried out in this paper, and the roll-over size variation during the conventional and ultrasonic vibration assisted fine blanking process were compared. The results show that the experiment result has a good agreement with that of the finite element simulation. From this research, it can get that the ultrasonic vibration can greatly reduce the roll-over size, and it has a promising future to be used in the fine blanking process.
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