Research On Anti-friction Mechanism Of Cutting Tool Based On Pangolin Scales Texture Feature

Tool plays an important role in the process of mechanical cutting. The friction between tool and workpiece is one of the most important reasons for the tool wear in practice. On the basis of previous bionic tribological study, the truth is not like that the smoother the surface, the smaller the friction. It usually will have a small friction with a range of micro texture unit on non-smooth surface. Designing micro texture on tool rake face, it has the function of reducing friction by setting reasonable texture parameters according to bionics principle. It will produce secondary cutting on workpiece when the texture parameters is large. In other words, it not only can not play the role of reducing friction, even may have a negative effect.This thesis designs tool rake face employing the method of biomimetic micro texture, which can reduce cutting force and improve tool life. The specific research contents are as follows:Firstly, the current researches about non-smooth surface and the type, size, model of biomimetic micro texture are analyzed. Meanwhile, the purpose and meaning of this paper are introduced.Secondly, pangolin scales micro texture is selected based on bionics principle. Its mathematical model is established through data fitting in order to provide references to the design of micro texture on the tool rake face. The cutting force, cutting temperature and equivalent stress are analyzed in the process of two-dimensional orthogonal cutting.Thirdly, the finite element model is created by using Abaqus. The process mainly can be divided into the following parts:building geometric model, meshing of tool and workpiece, creating material for model and fracture criterion, setting boundary conditions, establishing chip separation criteria and friction model, submitting the operation task.Fourthly, the cutting numerical simulation about pangolin scales texture and no texture are carried out by adopting Abaqus. The stress distribution, cutting force and temperature of the above two simulations in the whole cutting process are compared and analyzed. In addition, the researches on the texture parameters, cutting force, maximum stress and cutting temperature of triangular texture and scale type texture are studied. The final simulation results show that the stress distribution of scale type micro textured tool is more uniform and the cutting force, temperature are relatively small compare with non-texture. In the condition of secondary cutting, the scale texture has a better effect on reducing friction compare with Triangular texture.Finally, the effect of micro texture parameters on the performance of reduce friction and anti-friction mechanism are analyzed. Texture can reduce the actual contact area between tool and workpiece with its advantage of storaging chip and reduce contact length of chip. Scales texture can also generate additional fluid dynamic pressure to form the lubrication film. However, the width of the scale texture is too large to generate secondary cutting, it has negative effect on friction. The function of anti-friction is weakened when texture space is larger and the number of texture is less. The effect of micro texture depth on the friction reduction is relatively small, because the contact length between tool and chip approximately keep unchanged when the value of width and space is fixed. Therefore, cutting forces are rarely affected.