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Energy Dissipation Characteristics Modelling for Hot Extrusion Forming of Aluminum-Alloy Components
Hongcheng Li,Yuanjie Wu,Huajun Cao,Feng Lu,Congbo Li 한국정밀공학회 2022 International Journal of Precision Engineering and Vol.9 No.6
The hot extrusion forming process is widely used to process aluminum-alloy components in both the automobile and aircraft manufacturing industries. Since it involves pushing the material through the die at increased temperature, it is very energy-intensive despite requiring less blank material allowance. During hot extrusion forming, the multi-stage dynamic conversion of electricity, mechanical energy, and hydraulic energy to heat results in high energy dissipation. In order to improve the power and energy conversion efficiency of hot extrusion forming process, it is necessary to identify the energy dissipation characteristics. The transfer and conversion paths of the electrical, mechanical, and hydraulic energy from the motor to the hydraulic cylinder were firstly depicted based on the motion cycle of the extruder. A bond graph-based energy dissipation model was then proposed for dynamically identifying the energy-saving potentials. The energy dissipation model integrated the power bond graph sub-model of energy conversion elements such as motor, pump, hydraulic valve group, and hydraulic cylinder. These power bond graph sub-models were separately developed to find the energy dissipation state equations of energy conversion elements. An experiment was carried out using data obtained from the energy management system to validate the bond graph-based energy dissipation model. The results have shown that the power and energy conversion efficiency of hot extrusion forming is primarily controlled by the parameters such as extrusion velocity and extrusion force. Both the higher extrusion velocity and lower extrusion force will reduce the power and energy conversion efficiency. An optimal combination of extrusion velocity and pressure can achieve the lowest energy consumption per unit product.
Electro-hydraulic coupling jet printing technology based on Weissenberg effect under pulse voltage
Jing Wang,Xintao Wu,Wei Wang,Bing Xu,Yuanjie Fang,Jing Tang 대한기계학회 2021 JOURNAL OF MECHANICAL SCIENCE AND TECHNOLOGY Vol.35 No.6
In this paper, electro-hydraulic coupling jet printing technology based on the Weissenberg effect is put forward for the first time, and the pulse voltage is used to realize the on-demand printing. The experimental results show that the Weissenberg effect can inhibit the solution reflux and make the solution converge into a cone tip at the nozzle, which is more conducive to position printing precisely. By exploring the influence principles of process parameters on printing, it is found that droplet diameter is positively correlated with rotation speed and negatively correlated with voltage frequency. The printing frequency is negatively correlated with the rotation speed and positively correlated with the voltage frequency. However, the effect of voltage amplitude and duty ratio on the printing effect is not obvious in a certain range. It is found that the rotation speed of needle core within the range of 1800 r/min-7500 r/min can print out the ideal lattice structure, which proves the feasibility of this system to realize on-demand positioning printing. Finally, by using the printing equipment, the sacrificial layer structure of PDMS microfluidic chip was successfully made and the function of the microfluidic chip was realized, which further verified the practicability of the technical scheme proposed in this paper.