Research On Dry Cutting Performance Using A Micro-Grooved Tool

Dry cutting without coolant or lubricant is the major way in “green cutting”. However,the traditional dry cutting way produces high temperature, which will accelerate tool wear. Ithas been known that the micro-groove array on tool rake surface can improve the lubrication.However, micro-manufacturing is mainly relied on light and chemical etching, whosemachining accuracy is difficult to controlled and the size of micro-structure is smaller that7m, moreover, these micro-manufacturing ways may lead to corrosive liquid pollution. Thus,a micro-grinding approach is proposed to fabricate micro-groove array on tool rake surfacesof cemented carbide and CBN tool, for the purpose of environmentally friendly drycutting.During the experiments, the shearing angle, chip deformation, cutting temperature,cutting force and tool wear were investigated, the feasibility of titanium and die steel drycutting were investigated according to the chip flowing and heat transfer.Firstly, micro-grinding were performed on the rake surfaces of cemented carbide andCBN tool by using the diamond grinding wheel V-tip on the precision CNC grinding machine.It’s showed that micro-groove arrays with7m~155.1m in depth,0.14~0.65in depth towidth ratio can be fabricated on the rake surfaces. And better micro-groove surface qualityand form accuracy can be achieved by micro-grinding rather than laser machining.Then heat-up experiments were performed to analyze the correlation between rakesurface temperature and cutter tip temperature. As a result, the micro-grooved tools possessfaster heat transfer speed, rake surface temperature may be used to predict cutter tiptemperature because they are very relative. This experiment has started a new approach topredict the cutting tip temperature rather that simulation analysis.Finally, dry cutting experiments of Ti-6Al-4V,#45steel and die steel were performedusing micro-grooved tools with different micro-groove sizes and orientations. A size effectmodel between chip size and rake surface micro-groove size was built based on the diagonalmicro-grooved tool. It’s found that the micro-groove array can be valid only while themicro-groove interval wvis smaller than the cutting depth ap，and the micro-groove aspectratio γ is bigger than0.25, the micro-grooved tool can greatly decrease cutting temperature, cutting force, increase shearing angle, slow down tool wear and increase workpiece surfacequality. Moreover, the parallel micro-grooved tool can also improve dry cutting performance,but can not lead the chip flowing direction. The integrity of cutting edge greatly affects thedry cutting performance of micro-grooved tool, the one with impaired cutting edge acceleratetool wear and decrease the surface quality of workpiece.Thus, the micro-grinding technology using diamond wheel V-tip can be applied tofabricate micro-groove array with high accuracy and surface quality on the rake surface ofsuper-hard tools such as cemented carbide and CBN. The micro-grooved tool with optimizedmicro-groove parameters deduced from chip flowing and heat transfer effect can realize“green cutting” of hard-to-cut materials such as titanium alloy and die steel.