Numerical Simulation And Experimental Study On Deep-hole Drilling Process Of Staggered Tooth BTA Drill

Deep-hole drilling is a crucial process in the mechanical processing field and possession around 40% in machining hole.There always has the problem of complex machining process and difficult removing chips,which restricted the development of the deep-hole processing technology.This paper taking the staggered tooth BTA deep-hole drill as the research object,using finite element simulation and combining the experimental method to studied the process of deep-hole drilling,researched the chip formation mechanism,chip morphology,drilling force and temperature,this provides the reference for cutting process parameters optimization and design the staggered tooth BTA drill.This paper summarized working principle and characteristics of several common deep-hole drilling system,researched the cutting mechanism and BTA deep-hole drilling principle,analyzed the staggered tooth BTA drill drilling force sources,established the drilling force model,obtained the drilling force of staggered tooth BTA drill and the individual component of the cutter tooth,as well as the force of the guide pads.Summarized design features of staggered tooth BTA drill cutter tooth and guide pads,the three-dimensional model of the BTA deep-hole drill was established based on Solid Works.Applied the finite element simulation software DEFORM-3D,established the simulation model,used the Oxley model as the constitutive model of materials,set motion scheme of tool and workpiece and boundary conditions,defined the master and servant relationship between objects,realized simulation the process of BTA deep-hole drilling.Analysis the chip formation and deformation law,drilling force and temperature,study axial force,torque,chip morphology and tool-chip contact length variation with cutting parameters.The results show that,the cutter tooth cutting conditions gradually deteriorate,the chip deformation increased,and the extrusion deformation is growing worse along the drill bit outer circle to geometry center;For the staggered tooth BTA drill,internal tooth chip morphology are short spiral,middle tooth are C glyph,external tooth are commonly short strip or conical;Tool-chip contact length coefficient increases with the increase of feed rate,decreases with the increase of spindle speed and workpiece material strength,in addition,tool-chip contact length are the largest in the rake surface of the external tooth,minimal in internal tooth;drilling force and temperature increases as feed rate and spindle speed and workpiece material increased,but feed rate influences drilling force more,the spindle rotational greater influence on the temperature,drilling temperature along the drill bit geometry center to the outer circle is gradually rising.The experimental platforms of BTA drilling and drilling force testing system are established,using single-factor and multi-factor experiment method,obtained the different chip form and the law of chip deformation,got the changing rule of the axial force and torque under different cutting tool,the workpiece materials and different cutting parameter in the deep-hole drilling.The results show that,the thickness of chip deformation coefficient increases with the increase of feed rate and workpiece material strength,but decreases with the increase of the rotational speed of the spindle,the internal tooth deformation coefficient are maximum,minimum external tooth;Drilling force variation law is consistent with the simulation results,drilling force increases as feed rate and spindle speed and workpiece material increased,domestic tool axial force is 1.8 times the import tool,torque is 1.4 times,the domestic tool performance is not comparable with the import tool.In the end,obtained the empirical formula for the staggered tooth BTA drill drilling the workpiece material is 45 steel and 20 CrMnMo.