High Precision Drilling Technology Of Deep Holes In Aerospace Titanium Alloy Parts

Titanium alloy is widely used in the aerospace and other high-end manufacturing fields because of its high specific stiffness,high strength-to-weight ratio,low density,corrosion resistance and good anti-fatigue performance.As more thin-walled and compound titanium alloy parts are designed,structures like large length-to-diameter ratio holes,deep holes in the irregular section,high precision deep holes are widely applied.It’s rather important to research the machining technology of compound deep holes in thin-walled aerospace titanium alloy parts.As one of the highly efficient machining technologies of deep holes,gun drill is a single cutting edge,self-pilot and outside chip-remove drill.High pressure cutting fluids bring out the heat and break and remove chips through drill pipe of the gun drill during machining,while guide stripes at outer diameter ensure the correct feed direction.This thesis carried on theoretical analysis,finite element simulations and tests on gun drill’s drilling process.Firstly,a gun drill force system was established;secondly,a 3-D finite element simulation of gun drill was done,the results,such as drilling forces,drilling temperature,chips and tool wear,of the simulation were discussed;thirdly,drilling tests of TC4 were conducted,whilst cutting temperature was real-time measured,machining precision,surface quality and work hardening were off-line measured and discussed.A verification test of compound step deep holes in thin-walled titanium alloy parts was carried out combining the results of previous simulation and tests.A best fit machining parameter was got,therefore,a reliable and mature processing technology was formed and used in production line successfully.This thesis solved the problem of machining of compound deep holes in thin-walled titanium alloy parts,thus provided technical support to actual production,and finally improves the production efficiency.