The Performance Analysis For The New-type High-speed And Precision Double-contcact Toollholder

The high-speed-machining(HSM) is a new technology developing more than tenyears. HSM can improve the processing efficiency in large scale, reduce the cuttingforce and the cutting temperature, enhance the cutting tool abrasive resistance and theprocessing surface quality, realize highly effective and the precise union. Underhigh-speed condition, the toolholder-spindle structures are the most flexible part in themachine tool, and which positioning accuracy and connecting stiffness influence thecutting regimes and surface finish of the machined surface directly. therefore, manystudies have been carried out to analyze the toolholder-spindle connectingperformance and optimize the toolholder structure. The newly developed precisiondouble-contact BTF toolholder is applied to HSM, which has advantage of beingsuitable for both conventional BT spindles used in machine tool and high speedmachining for its7/24taper shank. It has theoretical and practical significance tocarry out basic study on BTF toolholder.Based on analysis of various high speed toolholder system at home and abroad,the connecting performance of BTF toolholder is studied using FEM contact modeland spring-damper model in this paper. The contents are as following:(1) Through systematically analyzing the structure and performance of BTFtoolholder by comparing that of BT toolholder，this paper clarifies the meaning of itsunique structure and its superiority to that of the structural. It provides theoreticalproof to build numerical model correctly.(2) Mechanical model of BTF toolholder was built out; limited bending momentequation increase with axial pressure in on the end face of the toolholder. Underhigh-speed condition, there will be clearance gap in the taper interface andconcentrated stress at the end of the taper shank, which will effect the connectingperformance of BTF toolholder.(3) Base on finite element contact analysis, it indicates that the contact ratio oftaper interface and the tip displacement of the BTF toolholder increase with theclamping force. Meanwhile, the law of disk spring effects the connecting performanceis studied, and the recommended stiffness of disk spring is1.2KN/mm. Throughcomparing the contact ratio, stress distribution and tip displacement of BT toolholder,the advantages of the BTF toolholder is verified. (4) Identify the dynamical contact parameters for spindle-tool holder interfacebase on frequency response functions. Using the spindle-tool holder system of BTF40as an example, identify the dynamical contact parameters. Then model the interfaceby using matrix27element, analyze and simulate the static and dynamiccharacteristics of the machine tool. The result show that the joints modeling method isfeasible.(5) Developed the system for BTF toolholder parametric modeling andconnecting performance simulation based on of ANSYS. It developed a new route forthe research and application of BTF toolholder.The research results enrich design theories of tool system in HSM, improve theability of research and development on tool system in China, narrow the study gap ontool system between China and developed countries, and provide powerful technicalsupports on manufacturing and using of tool system in HSM.