Laser forming: Overview of the controlling factors in the temperature gradient mechanism

Abstract

Laser forming (LF) offers the industrial promise of controlled shaping of metallic and non-metallic components for prototyping, the correction of design shape or distortion, and precision adjustment applications. The potential process advantages include precise incremental adjustment, flexibility of application, and no mechanical ‘spring-back’ effect. To date, there has been a considerable amount of work carried out on two-dimensional LF, using multi-pass straight-line scan strategies to produce a reasonably controlled bend angle in a number of materials, including aerospace alloys. A key area, however, where there is a limited understanding, is the variation in the bend angle per pass during multi-pass temperature gradient mechanism-based LF along a single irradiation track, in particular, the decrease in the bend angle per pass after many irradiations for a given set of process parameters. Understanding this is essential if the process is to be fully controlled for a manufacturing environment. The research presented in this paper through empirical data and numerical simulation of the LF of sheet mild steel, Ti6Al4V and AA5251, by CO2 laser offers a novel coherent picture of the key influencing factors and at which point in the bend evolution each is dominant, which has not been presented before.