Structural Optimization Design Of Negative Pressure Chip Removal Device For Deep Hole Processing

In the field of deep hole processing,there are many problems,such as high oil temperature,inappropriate observation,difficult chip removal and chip breaking,which are recognized as a major difficulty in the current machinery manufacturing industry.In order to solve the problem of chip removal in deep hole processing,a negative pressure jet model was established on the basis of studying the mechanism of negative pressure chip removal.In view of the energy loss caused by the front and rear separation zones of the model,three improved negative pressure chip removal structures are proposed based on the existing negative pressure chip removal devices:(1)wedge negative pressure device;(2)pre-jet hole negative pressure device;(3)contraction ring negative pressure device.Through theoretical analysis and fluent simulation optimization test,the existing structures and three new structures are compared and analyzed through the parameters of negative pressure,velocity and turbulence energy.It is verified that the three new negative pressure chip removal devices have better suction effect than the existing negative pressure chip removal devices.The optimal solution sizes of the three structures are determined.(1)The optimum size of negative pressure device with wedge structure is L1=75mm,L2=1mm,turbulent energy value is 0.0279045,negative pressure value is-2047.14 pa,velocity value is 2.44602m/s.Compared with the existing negative pressure device,the negative pressure value is increased by about 7.3 times,the velocity value is increased by about 18.4%,and the turbulent energy value is increased by about 18.4%.(2)The optimum size of negative pressure device with pre-jet hole structure is N=12;when D=0.3mm,the effect is the best,the negative pressure area is the largest,and theminimum negative pressure value is-1804 Pa.On the basis of the existing structure,the negative pressure value is reduced by 6.4 times.(3)The optimum size of negative pressure device with contraction ring structure is X=40,Y=1mm,turbulent energy value is 0.0604242,negative pressure value is-2466.53 pa and velocity value is 2.53417m/s.Compared with the existing negative pressure device,its negative pressure value increased by about 8.8 times,the velocity value increased by about22.7%,and the turbulent energy value increased by about 2.28 times.Three improved negative pressure chip removal devices are proposed to reduce the energy loss in the front separation area to the greatest extent and enhance the ability of negative pressure chip removal.By comparing and analyzing the three structures,the shrinkage ring structure has the best chip removal effect.In order to be better applied in the field of mechanical processing,the compound elliptical shrinkage ring structure is proposed for further design of the optimal shrinkage ring structure.Finally,the composite elliptical shrinkage ring structure is put forward.When the distance between the center of compound ellipse and nozzle is 70 mm,the best chip removal effect is obtained.Turbulence energy value is 0.091,negative pressure value is-2494.04 pa and velocity value is 2.54133m/s.Compared with the existing negative pressure chip removal device,the negative pressure value is increased by about 8.8 times,the velocity value is increased by about 22.7%,and the turbulent energy value is increased by about 3.4 times.It proves that the structure has the best chip removal effect,reduces the energy loss in the front separation area to the greatest extent,and enhances the negative pressure chip removal ability,which provides a technical idea for the optimization of deep hole processing and manufacturing technology.