LASER FORMING OF METALLIC DOME‐SHAPED PARTS USING SPIRAL AND RADIAL‐CIRCULAR SCAN PATHS

Laser forming process is a new flexible forming process without any contact between rigid tools and sheet metal, in which the form of a sheet metal is changed permanently by high thermal stresses caused by laser. In general, laser forming of spatial shapes and laser forming of two dimensional simple shapes are different. On one hand, heating path and pattern of thermal stress are increasingly being used in a laser forming process, which are especially important in forming three dimensional complicated parts. In a laser forming technique, a desired final shape can be achieved by a control of the laser scan path and other process parameters such as laser irradiation pattern, laser power, speed of laser scan and laser beam diameter. A new application of the laser forming process is production of dome‐shaped parts as a prototype. For the production of curved parts, especially for the dome ‐shaped ones, different strategies have been developed which are mostly based on curved irradiation paths. In this paper, a circular‐radial strategy of scanning path to form dome shapes by using laser is investigated. Experiments have been carried out to validate the numerical results. As a result, a new scanning pattern is presented as a spiral strategy. It was shown that the stress distribution is more uniform in laser forming with the use of spiral scanning path. In addition, the deformed parts with spiral scanning path are more uniform compared to other scanning paths investigated. Furthermore, it was found that laser forming with radialcircular scan paths will result in buckling mechanism whereas spiral irradiation will lead to gradient mechanism. The study also shows that radial and circular irradiations lead to occurrence of low thermal gradient and buckling mechanism. Additionally, low thermal gradient and buckling mechanism is happened by spiral irradiation. Finally, thickness distribution and temperature gradient of the deformed parts caused by different laser paths have been investigated.