Optimal Design Of Focused Jet For 3D Electrodeposition Micromachining

Jet Electrochemical deposition is a kind of high-speed electrodeposition technology.The flexibility of the jet beam is easy to control,the processing speed is quick,the operation is simple and so on,which gives the technology a good application potential in the field of material production.Because of the core problem of the preparation of high-quality jet has not yet been solved,so far this technology has not yet made a satisfactory three-dimensional microstructure or parts.On the other hand,based on the unique working mechanism,Flow Focusing can break through the traditional method of the jet preparation,which provides support for the realization of long range,large jet velocity,high flow field quality,strong domain and focusing superfluous jet.In view of this,this study integrates the Flow Focusing into the Jet Electrochemical deposition to replace the conventional open jet(single electrolyte)with the high-quality micro-jet(the outer layer is low-conductivity high-speed fluid such as nitrogen or deionized water and the kernel is the electrolyte),forming a new Jet Electrochemical deposition technology-focused jet 3D-electrodeposition.This dissertation which was supported by the National Natural Science Foundation(51475149)of China-focused jet 3D-electrodeposition took the the optimal design of focused jet for 3D-electrodeposition micromachining as the theme,in order to find out the influence of process parameters on the focusing jet.Details are as follows:(1)The flow field characteristics of the focused jet are simulated and analyzed.The influence of poor gas pressure-ΔP,the liquid flow rate-Q,focusing jet formation parameters(the distance between the nozzle and the focusing hole-H,the diameter of focusing hole-d,the length of the focusing hole-L))on flow field characteristics were also explored.The results show that the focused jet compared to conventional jet,can significantly improve the jet flow rate,make the jet more concentrated to have a smaller diameter,at the same time,improve the jet flow velocity uniformity.The diameter of the jet increased with the increase of ΔP,Q,H,L,and the isothermal region is positively correlated with the other parameters except that it is negatively correlated with ΔP.In order to obtain a jet with a higher flow rate and a more uniform flow rate,the liquid flow rate Q,the distance between the nozzle and the focusing hole,and the length L of the focusing hole are appropriately increased.To obtain a smaller diameter jet,the liquidflow Q should be reduced as appropriate.(2)The experimental system of focused jet observation was developed.A special device for preparing for focusing jet was developed,a integrated experimental platform for focused jet 3D-electrodeposition was set up.The influence of the gas pressure difference ΔP,the liquid flow rate Q,the distance between the nozzle and the focusing hole H,the diameter d of the focusing hole and the length of the focusing hole on the flow field characteristics of the focused jet are analyzed experimentally.The results show that the five parameters all affect the length of the focus,they are positively correlated or negative correlation.The experimental results are in good agreement with the simulation results,that is,the diameter of the jet is mainly affected by the liquid flow rate Q and the gas pressure difference ΔP,but not with the other parameters.From this chapter,combined with the simulation of the previous chapter,it can be concluded that it is necessary to increase the gas pressure difference ΔP and the distance between nozzle and focusing hole H,slightly increase the liquid flow Q,while appropriatly decrease the diameter of the focusing hole d in order to obtain a jet with smaller diameter,longer length,larger flow rate and more uniform flow velocity.And the length of the focus hole L should be adjusted appropriately basing on the combined effect of the above parameters.(3)The experimental of focused jet electrodeposition was carried out and the effect of focusing jet formation parameters on the three-dimensional profile of the deposition layer was analyzed.The results show that increasing the poor gas pressure ΔP and decreasing the liquid flow rate Q can improve the limits of the deposition process.While the structural parameters of the focusing device have little effect on the domain.In order to obtain a better sedimentary layer,the gas pressure difference ΔP should be increased and the liquid flow rate Q should be appropriately reduced.The influence of the above-mentioned focused jet jet parameters on the sedimentation domain is closely related to the influence of the focusing jet formation parameters on the flow field characteristics.