Study On Chip Breaking Mechanism And Processing Technology Of Single Tooth BTA Deep Hole Drill For Slender Shaft

In deep hole machining,when the staggered BTA drill with double chip removal ports is used for deep hole machining,due to the staggered arrangement of its cutter teeth,the chip breaking process does not interfere with each other,the chip removal effect is good,the machining process is stable,and high drilling efficiency and good machining quality can be obtained.For deep and long holes with small aperture and large depth diameter ratio,single tooth BTA drill is generally used for deep hole processing due to the high manufacturing cost of staggered tooth BTA drill and the limitation of space size on tool structure.However,the area of chip removal of single tooth BTA drilling tool is small,which makes the chips easy to curl and wrap and difficult to discharge from the processing area and which is easy to affect the stability of the processing process and the surface quality of the inner hole.In order to improve the drilling technology of deep eyelet of aviation slender shaft,ensure the machining quality and improve the production efficiency,it is necessary to study the chip breaking problem and the selection of cutting parameters in deep small hole drilling.In this paper,the chip breaking problem of single tooth BTA Deep hole drilling is theoretically analyzed,numerically simulated and experimentally studied for the machining of slender shaft deep hole:(1)Based on metal cutting theory and chip deformation principle,the chip bending deformation process is analyzed,and the relationship between chip breaking is established by using the maximum cutting stress theory.According to the deformation process of the chip on the chip breaking groove,the relationship between the geometric parameters of the chip breaking groove and the minimum limit feed is established.The effects of groove width,cutting edge height and normal rake angle on the minimum limit feed are further studied.Finally,according to the material properties of the processed material,three kinds of cutting tools with different groove widths are designed.(2)The two-dimensional turning simulation of the above three tools is carried out by using the finite element software,and the turning tool with good chip breaking function is designed based on the chip breaking effect of the tool in the simulation.Then the turning experiment is carried out to simulate the process of single tooth BTA Deep Hole Drilling and study the chip breaking of deep hole drilling.(3)Combined with the chip breaking table structure of single tooth BTA drill blade,the BTA drill blade is designed.Then,the single tooth BTA Deep Hole Drill experiment is carried out with different cutting parameters.Taking the chip shape as the analysis object and the inner hole surface roughness and straightness as the evaluation index,the influence of cutting parameters on machining slender shaft with single tooth BTA Deep hole drill is studied and analyzed,and the technology of machining slender shaft with single tooth BTA drill is improved.This process can meet the technical requirements: the roughness of the inner surface of the deep hole is less than 1.6 μ m.The straightness is less than 0.05 mm / m.In this paper,the chip breaking mechanism and experimental research of single tooth BTA Deep Hole Drill provide a certain reference value for the machining of deep holes.