Liquid Infiltration Mechanism In Contact Interface Of Rough Surface And Regulation And Control Of Tool–chip Friction

Metal cutting is the most common and major process manner in mechanical manufacturing industry.In metal cutting process,only 30-50% of the energy is effectively used as a result of a severe friction at the tool-chip interface which limite the machining efficiency of machine tools and the development of green cutting technology.Metal cutting is a complex systems with many factors coupling impact,for example tool-chip interfacial friction,cutting parameters,tool surface morphology,contact mechanical behavior of interface,cutting fluid infiltration,and so on.In this system,the cutting fluid infiltration,contact behavior and lubrication condition of tool-chip interface are all affected by tool surface morphology,and the friction at the tool-chip interface can be regulated and controlled by tool surface morphology for this coupling impact relationship.Therefore,the mechanism of fluid infiltration in contact interface of rough surface was firstly studied with numerical simulation,theoretical analysis,and experimental method.And,the correlation mechanism among textured type,surface morphology parameters,fluid wetting,and interfacial friction were also analyzed in this study.At the end,a new surface textured type was designed and manufactured on the tool rake face with laser processing technology based on these research results,which regulated and controlled the lubrication and friction condition of the tool-chip interface.These studies are of great significance to improve machining efficiency of machine tools and promote the development of green cutting technology.On the basis of the analytical results,the findings are concluded as follows:First of all,an innovative numerical model of contact interface of rough surface was presented and established according to the surface roughness theory and contact mechanical behavior of interface of the sliding zone of tool-chip interface.The infiltration property of fluid and the influence mechanism of surface texture on this property in contact interface of rough surface were studied basis on this model.Analytical results indicated that the micro-channels in contact interface of rough surface were the path of fluid infiltration.Empty cluster number was a crude evaluation of the fluid infiltration and storage in interface.A reasonable textured parameters and contact mechanical behavior of interface could achieve the best effect on improving the fluid infiltration and storage in contact interface of rough surface.Next,the contact characteristics of rough surface,mechanical driving mechanism of fluid infiltration under the action of wetting,and the area ratio of fluid infiltration in interface were obtained and anslysed on the base of liquid film thickness measuring instrument.Meanwhile,the directional motion of fluid in a conical micro-channel was studied with numerical simulation method.Analysis results showed that a power function law between interfacial normal stress and real contact area ratio existed in contact interface of rough surface.And the infiltration path and distribution pattern of fluid in interface were affected by the capillary force which was the result of surface wetting and micro-channel shape.Moreover,the directional motion characteristics of fluid in a conical micro-channel was affected by micro-channel parameters and solid-liquid interfacial wetting.Third,the influence of the surface texture of cemented carbide,contact mechanical behavior of interface,and fluid wetting on frictional properties under a water-miscible cutting fluid environment were investigated with a pin-on-disc reciprocating tribometer.Moreover,the correlation mechanism among textured type,surface morphology parameters,fluid wetting,and interfacial friction were also analyzed and clarified in this study.Lastly,a new conical micro-grooved texture was designed and fabricated on the tool rake face using laser texture technology based on previous research results.Analysis results showed that this tool surface morphology could formed micro-channel at the toolchip interface which improved the infiltration and storage of cutting fluid in tool cutting process.So the lubrication and friction condition at the tool-chip interface was regulated and controlled with morphology parameters of tool surface.This conlusion was also validated with metal cutting test.