Precisely regulating thermal deformation behavior of wire electrical discharge machining thin-wall fin via pulsed laser-induced shockwave

Abstract

The thermal deformation in the process of thin-walled metal fin processed by wire electrical discharge machine (WEDM) is almost unavoidable, which restricts the application of wire electrical discharge machining in the precision machining of thin-walled parts. In this study, a new process of thermal bending deformation regulation by laser-induced shockwave of wire electrical discharge machining thin-wall fin was proposed to obtain low/no deformation thin-wall parts. The thermal deformation of thin-wall In718 metal processed with different wire electrical discharge machining parameters was calibrated, and the law between the thermal bending and the process parameters was obtained. The thermal ablation and laser shock thermal deformation regulation model was established to accurately describe the stress distribution and deformation behavior of thin walls. For In718 thin-wall fin with different thicknesses, the thermal bending deformation could be regulated by laser-induced shockwave. After adjustment, the warpage of all thin walls was only −0.174μm at the lowest, and the thermal deformation could be reduced by 98.35 % at the highest. Laser shock improved the surface integrity of thin walls, increased the surface hardness to 433.9HV, increased by 46.84 %; laser shock also reduced the surface roughness of thin walls to a maximum of 2.67μm, a decrease of 33.58 %. In addition, laser shock could reduce the number of large-size grains, increase the number of twins, refine the impact surface grains to a certain extent, and the particle size was reduced to 7.64μm, which was reduced by 45.62 %.