Precision Control And Numerical Simulation Research On Laser Bending Of Titanium Alloy

Laser bending is a new processing technology which induces the internal stress ofmaterial by laser heating to produce the deformation, with the characteristics of shortproduction cycle, large flexible and non pollution. Laser bending is a non-contact thermalcumulative forming technology which is suitable for process titanium alloys withcharacteristics of strong resilience and difficult to forming under room temperature.At first, the experiment of different parameters including laser scanning speed andlaser power is designed to explore the variation of TC4sheet’s laser bending angle. Theprocessing parameters of the maximum bending angle in the unit time under the conditionof sheet’s not melt have been found out. The results showed that titanium alloy sheet’sbending angle increased linearly with the scanning number, the laser power and the energydensity. The laser bending angle decreased with the scanning speed.The TC4titanium alloy sheet is extremely easy to be oxidatived under hightemperature. Also the "edge effect" of sheet is tend to emerge during the bending process.So the fixture have been used f or gas shielded and strengthen the scanning line’sstiffness.The effect of laser scanning strategy on the titanium alloy sheet with the optimalprocess parameters has been studied. The variation of titanium alloy workpiece’s size andshape has been explored by designing different laser scanning paths and distances betweenthe laser scanning lines. The laser scanning strategy which meets the processingrequirements of precision has been formulated. Heat affected zone microstructure showsthat acicular martensite which affects the material’s tensile strength, elongation andhardness has precipitated after phase transition.The physical computing model has been established by Ansys simulation software.After defining the relevant boundary conditions and simulating the cyclic loading of laserheat source, the temperature, stress and strain fields’ distribution nephograms of titaniumalloy sheet during the laser bending process have been drawn. And the variation curves ofthe nodes’ temperature, stress and strain have been studied. The simulation andexperimental results have been compared to verify the influence of the process parametersto bending angles. By simulating the sheet’ bending angles on whether the use of fixture through changing the constraint conditions, the strengthen of the scanning line’s stiffnessby using the fixture in laser bending to avoid the “edge effect” has been verified.