Chip Formation Mechanism And Tool Structure Optimization Of BTA Deep Hole Drill

Deep hole machining plays an important role in the field of mechanical manufacturing,especially in the manufacturing of special equipment.However,the basic theoretical research on deep hole machining tools is still lacking.In this paper,the chip separation state,cooling effect,chip flow direction,the position of the cutting edge of the central blade,the cutting force on the blade,and the working angle are deeply studied in order to reveal the working mechanism of BTA deep hole drill and provide theoretical reference for the structural design and optimization of BTA tools.The main research contents are as follows:(1)The chip separation mechanism of staggered teeth BTA tool is studied,and the research method of cutting section of each blade is put forward.The "complete chip splitting" state can further reduce the chip width.The cutting tool is parameterized and the criterion of chip separation state is given.The cross-sectional area and flow rate of the flank surface and the energy emitted by the flank under the condition of complete chip separation are simplified,and the chip removal coordination equation of the main chip removal hole is proposed.(2)The force of BTA tool is analyzed,and the force of each blade and guide bar of the experimental tool is obtained through experiments.The optimized structure meeting the chip removal coordination equation and the principle of uniform heat dissipation is designed.The force on the guide strip can be controlled by fine adjustment of δ,ε and the direction of the chip removal hole.(3)The cooling effect of the tool flank space before and after optimization is compared by using fluid simulation,and the heat dissipation efficiency of the optimized tool is improved.The temperature distribution of cutting fluid in the flank space is compared.After optimization,the area of high temperature zone is reduced and the cooling effect is improved.A boss is arranged between the center blade and the middle blade to further improve the cooling environment of the tool.(4)The influence of the relative position between the cutting edge of BTA tool and the tool center on the cutting state is studied.It is pointed out that the cutting edge of the central blade should be lower than and cover the cutting center laterally.Using vector method and MATLAB software,the working angle near the cutting center is solved.The influence of eccentricity on the minimum relief angle and the additional cutting force of the blade is studied.Optimizing the eccentricity of the tool is helpful to improve the service life of the central blade.It is pointed out that attention should be paid to the requirements of BTA tool structure for machining parameters in actual use.Unreasonable use may lead to rapid tool wear and even machining accidents.