Study On The Optimization Of CMQL Process Parameters In High-speed Milling Of 300M Steel

The development of green cutting technology provides a new solution for the cutting and manufacturing of traditional hard to machined materials.300 M steel for aircraft landing gear is a typical aeronautical difficult-to-machine material.The problems in the cutting process of 300 M steel show that the cutting force is large,the cutting temperature is high,the tool wear is serious,and the quality of the machined surface is poor.Cryogenic minimum quantity lubrication technology(CMQL)is composed of cryogenic cold air technology and minimum quantity lubrication technology.CMQL is especially suitable for the processing of difficult-to-machine materials because of its good cooling and lubrication effect,which can effectively reduce the friction between tool and workpiece and chip,inhibit cutting force,reduce the temperature of cutting area,delay tool wear and improve machining accuracy.In this paper,the CMQL technology is used to study the milling process of 300 M steel,and the process parameters for high speed milling of 300 M steel by CMQL are optimized.First,the influence of several green cutting techniques such as cryogenic cold air cutting,water mist cooling cutting,oil mist lubrication cutting and cryogenic minimum quantity lubrication cutting on the milling process of 300 M steel is compared and studied.By analyzing the change of cutting force and surface quality with the increase of cutting depth,the improvement effect of various cooling lubrication methods on the cutting process is explored.Then,the single factor test of CMQL process parameter milling 300 M steel is carried out.In the process of testing,the effect of cold air temperature,cold air pressure,the quantity of cutting oil and the quantity of cutting fluid on the milling process is reflected by the measurement of the cutting force and the surface roughness of the workpiece.The influence of CMQL process parameters on the milling process is investigated.Furthermore,the optimization of CMQL process parameters is carried out.The primary and secondary order of influence on the cutting force and the surface roughness is determined by the extreme analysis of orthogonal test.The empirical models of cutting force and surface roughness is established on the basis of the test results,and testing the significance of the empirical model and the coefficient of the model.Then the multi target process parameters are optimized through genetic algorithm.The results obtained can provide reference and guidance for the practical application of CMQL technology.Finally,the simulation model of cutting 300 M steel with CMQL conditions is established using simulation software DEFORM.The simulation model is used to simulate the characteristics of the stress distribution,the cutting temperature field and the cutting force,and the test results are verified.