Analysis And Improvement Of A Special Tool Holder For High Speed NC Machine Tool

Since the 21 st century,high-speed machining technology has become a more and more widely used advanced manufacturing technology.The machining system is composed of machine tool,tool clamping system and tool cutting part.As the link between the spindle and the cutting tool in CNC machine tools,the tool clamping system often plays a key role in the high-speed machining system.In this paper,a large number of cracks appear in the root of the special tool holder of a CNC machine tool,which affect the production safety,processing efficiency and cost.It is urgent to find out the reasons and propose solutions through theoretical analysis.The purpose of this paper is to analyze the cause of the tool holder's fatigue fracture and find out the most reasonable way to improve the structure of the tool holder,so as to prolong the service life of the tool holder.This paper first introduces the common theoretical system of high speed cutting,as well as the key technology of high-speed cutting and the research status of professional connection tools used in high-speed cutting system.Then,it points out the primary reason for the fatigue damage of the tool holder of HSK tool connecting system in use.The stress calculation formula of solid circular axis in high speed cutting system is derived,and the stress produced in the tool holder during high speed cutting is estimated.The causes of fatigue fracture of tool holder in long-term repeated use are analyzed,the material and surface were observed by electron microscope.Then it is determined that the stress concentration of the tool holder is mainly caused by the sudden change of the tool holder geometry.In this paper,Three-dimensional Modeling Software Solidworks and ABAQUS are used to do the simulation and calculation,the reasonable improvement method of tool holder structure is obtained.First,the tool holder of the research object is measured accurately by CMM,and import the measured data into the 3D Drawing Software Solidworks to build a mathematical model.Then the model is imported to ABAQUS for numerical simulation.Through the mechanical analysis,observe the stress concentration of the tool holder,and use finite element to verify the optimization results and choose the best optimization scheme.The final verification results show that the structure shape of the tool holder meets the requirements of relieving stress concentration and prolonging service life.The research results also have a certain reference value for the analysis and solution of similar problems of CNC machine tool connection system.