Research On Controlled Abrasive Flow Finishing Based On Hydrodynamic Effect

Aiming at the technical problem of achieving uniform,controllable and efficient removal of the tool marks after the work-pieces with free surfaces,complex cavity surfaces or thin walls have finished precision cutting processes,a new technology of abrasive grain flow finishing based on hydrodynamic effect is presented in this thesis.This is a kind of precision finishing method used on the high speed machine tool.It is to make the abrasive grain flow work on the surface of the part under the hydrodynamic effect to achieve the effects of having controllable finishing trace and relatively controllable micro removal,by adjusting the factors as the minimum space between tool and part,tool speed,feedrate,tool path and so on.The main work and achievements of this thesis are as follows:1.Pressure field and velocity field modeling of the abrasive grain flow based on hydrodynamic effect.The characteristics and flow state of the abrasive flow fluid are analyzed;the hydrodynamic effect of the wedge-shaped machining zone formed by the high-speed rotating tool and the workpiece is studied.The fluid pressure field model and the velocity field model of the wedge machining zone are established,and the distribution of the velocity field and pressure field is simulated and analyzed.2.Research on the abrasive grain removal mechanism based on hydrodynamic effect.Based on the micro-removal scale effect and dislocation propagation mechanism in micro cutting,the process of machining hardening,crack generation and crack propagation in this method was studied,and the micro removal mechanism of the abrasive finishing was researched.Based on mechanical energy conversion and force analysis,the macroscopic mechanism and controllable removal mechanism of abrasive flow finishing were studied.The experimental platform was constructed,and the removal mechanism was qualitatively verified.3.Research on the removal models of abrasive flow finishing under hydrodynamic effect.The movement of abrasive particles in the wedge space between tools and workpieces is analyzed.A single abrasive sliding removal model,a rolling removal model and an erosion surface removal model are established.The shear removal and extrusion deformation model based on the hydrodynamic effect is obtained.The energy loss caused by the interaction of multiple abrasive particles is considered,and the removal model reflecting the comprehensive effect of a number of abrasive particles for the abrasive finishing is established.The effect of abrasive and viscous base liquid on micro removal efficiency is studied.The rationality of the model is verified by finishing trace figures.4.Research on the finishing quality and efficiency based on the single factor and multi factors.Based on theoretical analysis and experimental research,the model of the whole quality and efficiency of the minimum clearance,tool speed,tool diameter,dynamic viscosity of abrasive mixture,particle size and tool feedrate is established,and the comprehensive evaluation index and weight factor of the optimization model of the abrasive finishing quality and efficiency are determined by using the fuzzy mathematics evaluation principle.Based on the experimental data,the relation matrix of factor combination evaluation is constructed,the membership function of the quality and efficiency model,the evaluation matrix is synthetically evaluated,and the optimization model of the quality and efficiency of abrasive finishing is established under multi factors.