Characteristics of the Thermal Strain of Gas Jet-Assisted Laser Percussion Drilling

In this work, a digital image correlation technique in combination with laser hole drilling to measure the residual thermal strain is presented. The significant potential benefits of this work are non-contact, high speed, and on-line measurement. The ring-core based groove in the surface of a specimen was drilled concentrically to induce thermal stresses inside the core. These deformations can be measured by a digital image correlation technique for measuring relieved strains. We also investigated the size of the reference areas on the specimens and tracked these areas after the laser hole drilling process. The proposed method was applied to characterize the thermal effect produced by laser milling for aluminum alloy Al5052 under plane strain tension conditions, and the results were compared with four assisted laser milling approaches.