Research On The Influence Of Tool Angle Change And Wear On The Machining Quality Of 304 Stainless Steel Deep Hole Gun Drill

With the continuous development of the manufacturing industry,the processing of small diameter,long and deep holes has a broad demand in key areas such as aerospace,weapons manufacturing,energy and chemical engineering.Gun drilling,as a typical deep hole processing method,is the most effective technical means to realize such processing at this stage.However,due to the complex structure of the gun drill bit and the different inclination angles of the inner and outer cutting edges of the gun drill,the processing axial drilling force is different.At the same time,with the continuous increase of the processing depth,the wear of the tool will increase,which will also affect the processing quality of the deep hole.304 stainless steel,as a common refractory material,is widely used in medical equipment,food processing,shipbuilding and other industries.However,due to the high viscosity of 304 material,the tool hardening is serious during machining,and it is easy to wear and stick the tool.Long-time processing will lead to the fracture of the cutting edge,which will lead to tool failure and affect the processing quality.For this reason,the influence of the change of cutting edge angle of gun drill and wear on the machining quality of 304stainless steel has been studied in this paper.The main research contents are as follows:（1）Research on the Cutting Force Model of Gun DrillFirstly,by studying the structure and mechanical model of the gun drill bit,the forces acting on the inner and outer cutting edges of the gun drill are analyzed.According to the established mathematical model,it is found that the cutting edge angle of the gun drill is the key factor affecting the drilling force of the gun drill.Then a verification test was carried out.According to the test results,it was found that the axial drilling force increased with the increase of the cutting edge angle,and the The increase of external angleα₁ has a greater impact on the drilling force,compared with the internal angleα₂.（2）Experimental research on variable angle machining of gun drillEight sets of machining experiments were conducted to change the angle of the inner and outer cutting edges of the gun drill to control the drilling force during the machining process.The experiment detected the changes in axial force at different angles.After that,through the analysis of the test results,the influence of the changes in the cutting edge angles of the inner and outer edges of the gun drill on chip formation,hole wall surface roughness values,and hole straightness errors were explored.The results show that when the outer edge angle is 30°and the inner edge angle is 25°,the machined surface quality is the best.When the outer edge angle is35°,the hole offset is better when the inner edge angle is between 20°and 30°.（3）Experimental research on abrasion processing of gun drillFirstly,the replaceable gun drill is selected as the machining tool for this test,and the selection test of wear test parameters is carried out.The appropriate processing parameters were selected by comparing the hole wall roughness and axial cutting force under different test parameters.Then the machining test of the replaceable gun drill is carried out,and the worn form of the blade’s front and rear tool faces are analyzed.Finally,the chip morphology,hole wall surface roughness value,hole straightness error value,and machining axial cutting force are investigated.The influence of the wear amount of the replaceable gun drill on the processing quality of 304 stainless steel deep holes is summarized.It is suggested that the blade can be replaced when the cumulative processing reaches more than 7000mm.This paper discusses in depth the influence of cutting edge angle changes and tool wear on hole processing quality of gun drills.The research in this paper has a certain guiding role for deep hole machining of 304 stainless steel materials.