Study On High-Speed Green Processing Technology Of Sn-Bi Alloy

Sn-Bi alloy is a kind of environment-friendly alloy.It is solid and silver-white at room temperature.It has high density,low melting point and strong permeability.It is widely used in die manufacturing,automotive industry,aerospace,nuclear industry,medical treatment,micro-electromechanical system(MEMS)and other fields.With the increasing demand of personalized customization in jewelry industry,Sn-Bi alloy is favored for its low cost,not easy to be oxidized by air and silver-white luster.Traditional jewelry production methods usually need to open the mould and then mass production by wax-loss casting.The process is complex,high cost and long cycle.Personalized customization usually needs fast response and the cost should not be too high.High-speed milling provides a solution to this problem.At present,there are few reports on the high-speed milling of Sn-Bi alloy at home and abroad,so it is of great significance to study the high-speed milling of Sn-Bi alloy.At the same time,our country attaches more and more importance to environmental protection,and jewelry is usually in contact with human skin,so this topic adopts dry cutting and low-temperature cutting methods for green processing,to avoid the harm of cutting fluid to the environment and human body.In this paper,high-speed milling experiments of Sn-Bi alloy were carried out by room temperature processing and ice-setting processing,and the effects of different processing parameters on milling force,roughness and cutting temperature were studied.Finally,the optimal milling parameters were obtained by using Taguchi method,and the experimental verification was carried out to provide reference for future actual production.The main research contents and conclusions are as follows:(1)High-speed milling experiments were carried out at room temperature and freezing conditions to study the influence of different milling parameters on milling force.Under room temperature and ice-setting conditions,the milling force increases first and then decreases with the increase of spindle speed,and increases gradually with the increase of feed and cutting depth.Comparing the influence of room temperature processing and ice-setting processing on milling force under the same milling parameters,ice-setting processing can significantly reduce the milling force,which can be reduced 50%.The linear regression analysis of milling force is carried out,and the milling force model of X,Y and Z directions under room temperature processing and ice-setting processing is obtained.(2)High-speed milling experiments were carried out at room temperature and freezing conditions to study the effect of different milling parameters on roughness.Under room temperature processing conditions,the roughness decreases gradually with the increase of spindle speed,increases first,then decreases and then increases with the increase of feed,and increases first and then decreases with the increase of cutting depth;under ice-bonded processing conditions,the roughness increases first and then decreases with the increase of spindle speed,and increases roughly with the increase of feed and cutting depth.The roughness gradually increased.Compared with room temperature processing,the roughness can be significantly reduced by ice-bonding.(3)High-speed milling experiments were carried out at room temperature to study the influence of different milling parameters on cutting temperature.Cutting temperature decreases with the increase of spindle speed,increases with the increase of feed rate and cutting depth.When the row spacing increases,the change of cutting temperature is not obvious.(4)The parameters of the factors affecting the roughness are optimized by Taguchi method,and the results show that the roughness is the smallest when the spindle speed is 20 000 r/min,the feed rate is 0.01 mm/r and the cutting depth is 1.5 mm under room temperature processing conditions,and the smallest when the spindle speed is 15000 r/min,the feed rate is 0.015 mm/r and the cutting depth is 0.5 mm under freezing processing conditions.