Research On Chip Removal Performance Of Internal Spray Turning Based On Fluid Solid Coupling

In the process of metal cutting,appropriate cooling methods can not only improve the quality of cutting,extend the service life of the tool,but also improve chip removal performance.At the same time,in the process of turning the inner circle,after the chips leave the workpiece,they tend to accumulate inside the workpiece.How to timely discharge the chips from the workpiece is an urgent problem to be solved in the inner circle turning process.The spray cooling chip removal method can solve the problem that it is difficult to discharge chips from the workpiece in internal turning.The spray cooling chip removal involves the interaction between fluid and solid.Therefore,based on the fluid solid coupling theory and simulation,this paper studies the influence of parameter changes on chip removal performance in internal spray turning.First of all,the initial velocity of chip separation from the workpiece is the basis of studying chip removal in internal spray turning.However,in the internal turning process,because the workpiece blocks the line of sight and other factors,it is difficult for the operator to measure the initial speed of the chip leaving the workpiece.Therefore,this paper uses the finite element software ABAQUS to simulate the internal turning process,and selects nodular cast iron as the workpiece material.The chip is easy to break and assumes a short spiral shape,which is not only representative,but also has a greater impact on the chip removal effect by changing the spray cooling parameters.Using the Johnson-Cook material constitutive model and JC damage evolution criterion,a simulation model was established for cutting speeds of90m/min,110m/min,and 130m/min at a feed rate of 0.1mm/r,and a cutting depth of 0.5mm,respectively.The initial velocities of chip detachment from the workpiece at three different cutting speeds were obtained.Secondly,the inner circle spray turning experiment of ductile iron workpiece was carried out,and the chips were collected and counted when the spray pressure was 0.1MPa,0.3MPa and 0.5MPa.After statistical analysis,the chips are sample Ⅰ and sample Ⅱ,accounting for60% and 40% respectively.After measuring two types of chip samples,a discrete element method was used to model,and a Hertz-Mindlin(no slip)contact model was used to simulate the contact collision between chip,chip,workpiece inner wall,and chip tool.Finally,the chip removal performance is studied based on the fluid solid coupling of the EDEM-Fluent software platform for the inner circle spray cooling turning mode.The fluid solid coupling analysis model of air,chip,tool and workpiece in inner circle spray turning is established by Euler Lagrange method,and the influence of spray pressure on chip removal performance in through hole turning is studied.By changing the hole type of workpiece,the difference of chip removal performance between through hole and blind hole turning under spray pressure is studied.By changing the cutting speed,the influence of cutting speed on chip removal performance of inner spray through-hole turning is studied.Specifically,it is divided into the following tasks:(1)The chip removal simulation of inner circle spray through-hole turning was carried out based on the EDEM-Fluent coupling.The cutting speed was 90m/min,the feed rate was0.1mm/r,and the cutting depth was 0.5mm.The spray pressure was 0.1MPa,0.2MPa,0.3MPa,0.4MPa,0.5MPa,0.6MPa,and 0.7MPa,respectively.The influence of spray pressure on chip removal performance was studied.The results show that when the spray pressure is less than0.5MPa,the higher the spray pressure,the better the chip removal performance;When the spray pressure is 0.5MPa,the chip removal effect reaches the critical value,and then the chip removal performance will not be improved by increasing the spray pressure.(2)The chip removal simulation of inner circle spray blind hole turning is carried out based on EDEM Fluent coupling,keeping the above cutting speed,feed rate,cutting depth and cutting position unchanged,and the influence of spray pressure on chip removal performance is also studied and compared with through holes.The results show that when the spray pressure is 0.1-0.4MPa,the chip removal performance of blind hole turning is better than that of through hole turning;When the spray pressure is greater than 0.5MPa,the chip removal performance of through hole turning is better than that of blind hole turning.(3)The influence of cutting speed on chip removal performance of internal spray through hole turning was studied,keeping feed rate,cutting depth and cutting position unchanged.The cutting speed is 110m/min and 130m/min respectively,and compared with the chip removal performance when the cutting speed is 90m/min.It is found that the larger the cutting speed is,the greater the spray pressure required to achieve the best chip removal performance is.