Structural Analysis And Key Manufacturing Technologies On BTA Deep Hole Drilling

Low Pressure Heater is one of important equipment in nuclear power industry,and it can reduce the energy loss and arise the cycle efficiency of thermal system.Within the manufacturing of plate of the heater,the deep hole drilling technology is a key point,and BTA(Boring and Trepanning Association)is applied.The chips can be removed from the inside hole of BTA by the high pressure cutting fluid.It is difficult to keep the high-quality hole due to the poor cutting condition,chip breaking,heat dissipation,and low rigid of the machining system.Therefore,towards those issues,this thesis presents the design principle of the BTA deep-hole drill,the guide of the chip breaker,the selection of tool materials,the optimization of cutting parameters,and the key manufacturing technology.Through analyzing the features and machining mechanism of the BTA deep hole drill,towards the features of BTA structure,the paper proposes the strategy of BTA insert distribution,the key points of guide block and chip breaker,and selection principle of the tool material.Targeting the validation and improvement of those research,the statics mechanics and modal are simulated for establishing the displacement deformation trend and the natural frequency vibration diagram of BTA in drilling,respectively.According to the actual drilling process of BTA,the physical model related to the cutting force is established.Also based on the wear distribution of the inserts on BTA,the influence of cutting parameters on the torque,axis cutting force and temperature are obtained by the result from the simulation of the inserts on BTA which is carried out in Third Wave AdvantEdge,aprofessional FEM software of cutting process simulation.Towards the technical challenges of manufacturing and application of BTA,the generation mechanism and influence factors of BTA drilling errors is studied first.Then this thesis present two aspect of researches.The manufacturing process of cutting tool,welding and grinding are analyzed accordingly,as well as the selection principle of cutting parameters,which provide the technical supports for high-quality deep hole with BTA.