Study On Topography Reconstructing Grinding Wheel And Grinding Experiment

Grinding can obtain high workpiece accuracy and surface quality,which occupies a high proportion in the advanced manufacturing field.However,the normal grinding wheel has a high wear rate because of its compact grain arrangement and easy impaction of debris.At the same time,most of the abrasive grains on the wheel surface are ground with negative rake angle during the processing process,which make the grinding force and temperature in the grinding zone to be large,leading to an inestimable impact on the accuracy and life of the processed materials.Changing the working topography of grinding wheel and improving the lubrication mode are effective means to reduce the debris adhesion,the grinding force and the grinding temperature,and improve the surface quality of the processed materials.For that,this paper proposes a new processing technology about the grinding process of hardened mould steel based on topographic reconstruction of the grinding wheel under the Nano-MQL condition.In this paper,the study of the topography-reconstruction grinding wheel using the diamond sheets was investigated,then the grinding experiments of the moud steel were operated under the Nano-MQL conditons.The main contents were as follows:1.The laser processing PDC method was used to obtain the diamond fiber with the sub-millimeter-grade cross-sectional dimension,and a diamond fiber sheet was obtained by artificially uniformly arranging the single fiber using the formation mold.After that one end portion of the fiber sheet was ground.Then,the ground fiber sheets were fixed to the fixture to prepare a diamond fiber cutting device.Based on the selected reasonable processing parameters,vertical micro-groove array?type I?were prepared on the surface of the grinding wheel which the arrays were perpendicular to the rotation axis of the grinding wheel.As the same,parallel micro-groove array?type II?and compound arrays of vertical and parallel micro-groove?type ??were prepared.2.Based on the normal temperature dry and pouring lubrication conditions,the compared grinding experiments of the mould steel using different grinding parameters were carried out with the normal,type I,type II and type ? grinding wheels,The results showed that compared with the normal grinding wheel,the topography-reconstruction grinding wheels reduced the grinding force and grinding temperature during grinding processes.With the comprehensive analysis of the grinding force,grinding temperature,profile and roughness of the workpiece,the type ? grinding wheel had the best grinding performance.3.The Nano-MoS₂ lubrication oil with different mass fractions were prepared by two-step method.It was found that when the mass fraction of Nano-MoS₂ lubricating oil was 2.5%,the anti-wear and anti-friction effect were the best through friction and wear tests.The compared grinding experiments of the mould steel using the type ? grinding wheel under the pouring and Nano-MoS₂ MQL were carried out.The roughness and morphology of the surface,the hardness and residual stress of the surface/subsurface of the workpiece after grinding were studied.The results showed that the thickness of the metamorphic layer under pouring lubrication is less than that of the Nano-MoS₂ MQL process with the same grinding parameters.Compared to the pouring grinding processes,the surface wear and roughness of the Cr12MoV mould steel decreased after the Nano-MoS2 MQL grinding processes using the type ? grinding wheel.