Study On Hard Cutting Performance Of The Cosine Enhanced PCBN Tool With The Structure Of Double Inclined Walls

The problem of chip obstruction accumulation is easy to occur in high speed hard cutting,which leads to the increase of cutting force and cutting temperature,and accelerates tool failure speed.The PCBN tool with cosine enhanced edge has the function of coordinating the direction of chip removal,and improves the state of chip outflow.However,after the tool wears,the cutting edge shape changes,the coordinated chip flow direction weakens,and the problem of chip accumulation is still unavoidable.For this reason,based on the cosine cutting edge,the enhanced structure is added to the rake face,and the cosine enhanced PCBN tool with the structure of double inclined walls is designed.At the same time,the cosine enhanced PCBN tool with the structure of double inclined walls in high speed hard cutting experiment was carried out,Compared with the PCBN tool with cosine enhanced edge,the cutting performance of the tool,such as tool wear,surface morphology,white layer,residual stress and so on,was studied.The research included the following aspects:Firstly,the design and fabrication method of the cosine enhanced PCBN tool with the structure of double inclined walls are studied.Aiming at the problem of chip obstruction,reducing cutting resistance and prolonging tool life in the cutting process,the cosine enhanced PCBN tool with the structure of double inclined walls was proposed,and the finite element simulation was used to simulate the contact length limit of the tool with cosine enhanced edge.The method of three dimensional precision laser machining was adopted.The cutting edge and the front face of the cosine enhanced PCBN tool with the structure of double inclined walls were prepared respectively.Secondly,The influence of tool wear on the chip macroscopic and microscopic morphology of two kinds of cutting tools was studied.With the increase of tool wear,chip accumulation occurs on rake face of the tool with cosine enhanced edge,while the cosine enhanced PCBN tool with the structure of double inclined walls had good chip removal performance,which effectively alleviates the chip accumulation problem caused by the wear of the tool rake face.Moreover,the cosine enhanced PCBN tool with the structure of double inclined walls has a relatively small degree of serration and a low degree of adiabatic shear.Then,The wear pattern and mechanism of the cosine enhanced PCBN tool with the structure of double inclined walls were analyzed.The results show that the cosine enhanced PCBN tool with the structure of double inclined walls the wear morphology was narrow arc shape and the wear area was smaller than that the tool with cosine enhanced edge.Finally,the surface integrity indexes of the surface morphology,white layer and residual stress of the two tools were compared and analyzed.The research shows that with the increase of tool wear,the three-dimensional roughness of the surface of the cosine enhanced PCBN tool with the structure of double inclined walls was obviously better than that of the tool with cosine enhanced edge.The white layer structure was relatively finer and more uniform,and had a deeper residual stress distribution.