Transfer Characteristics And Quantification Analysis Method Of The Cutting Heat In High-speed Dry Hobbing

Green manufacturing is one of the five major projects of “Made in China 2025”.The innovation of process theory,technology and equipment is necessary to industrialization implementation of green manufacturing.Gear is one of the key components for mechanical transmission.The use of large amount of cutting oil in conventional gear hobbing process results in serious workshop environmental pollution and occupational health hazards.In recent years,high-speed dry hobbing has received wide attention from domestic and international academic circles and industry,and been proved to be the dominating green technique of gear hobbing owing to its great advantages in increasing productivity,decreasing manufacturing cost and protecting occupational health.However,due to the lack knowledge of the mechanism of cutting heat transmission and regulation,a large amount of cutting heat generated in high-speed dry hobbing restricts the performance improvement on machining accuracy,thermal deformation,hob service life,etc.To this end,with the support of National Natural Science Foundation of China(Grant No.51475058)and 863 Program(Grant No.2012AA040107),the researches on transfer characteristics and quantitative analysis method of cutting heat generated in high-speed dry hobbing are conducted systematically in this paper.First of all,combined with the principle of multi-edge interrupted cutting,the characteristics of cutting heat generation and transmission in high-speed dry hobbing are illustrated.Furthermore,the three-stage model of cutting heat transfer in high-speed dry hobbing is developed.The first stage refers to the cutting heat generation due to material elasticoplastic deformation and friction and the cutting heat transfer on the cutting contact interface during material removal process.The second stage refers to the cutting heat transfer among chips,hob,compressed air and machined workpiece.The third stage refers to cutting heat transfer in cutting space of machine tool.Secondly,the methods for quantitative analysis of the chip heat-carrying capacity and temperature rise of hob are studied based on the 3D chip geometry.In the multi-edge hobbing process,a series of chips with different geometry are generated.Based on the thickness and volume of heterogeneous chips and the modified model of specific cutting energy,the calculation model of cutting heat in high-speed dry hobbing is presented.The quantitative analysis models of chip heat-carrying quantity and heat-carrying efficiency are developed based on the transfer characteristics of cutting heat in the first and second stages.Also,the quantitative model of hob temperature rise under the coupling effects of heat conduction,heat convection,and heat radiation are established.Thirdly,the study of heat balance model of cutting space and corresponding heat optimization method during high-speed dry hobbing are carried out.Based on the transfer characteristic of cutting heat in the third stage and the quantitative analysis of heat transfer among the chips,hob,workpiece,air and machine tool,the heat balance model of cutting space is developed.And then,an optiomization model is developed for minimizing the temperature rise at reference points in cutting space,where hob rotation,hob axial feed,compressed air temperature,mass flow rate of air are taken as control parameters.Finally,an application system for analysis of cutting heat and its thermal balance in high-speed dry hobbing is developed based on Mathematica software.And the developed system is verified by the application case.