Laser forming of materials without external forces

摘要

Investigations on bending plates by use of laser beam with rectangular cross-section are presented. Permanent deformation of plate is obtained without external forces, solely under influence of thermal stress induced by local heating of the material. Laser beam of narrow rectangular cross-section was modeled as linear heat source moving over the plate surface. Temperature distribution in the plastified layer of the material was taken into considerations. The bend angle was investigated as a function of laser beam parameters: power, cross-section geometric parameters, velocity with respect to the material and material parameters of bend plates. It has been proven that effective bending occurs when the material surface temperature is close to the melting temperature. Presented advanced analytical model can be applied in design and control of laser forming of developable surfaces, as well as in other laser processing technologies, hardening, for instance. Derived dependences for the bend angle and curvature can be reduced in special case to well-known expressions describing welding distortions.