David Peter Mika

Laser Forming of Varying Thickness Plate—Part I: Process Analysis

Laser forming (LF) is a non-traditional forming process that does not require hard tooling or external forces and, hence, may dramatically increase process flexibility and reduce the cost of forming. While extensive progress has been made in analyzing and predicting the deformation given a set of process parameters, few attempts have been made to determine the laser scanning paths and laser heat conditions given a desired shape. This paper presents a strain-based strategy for laser forming process design for thin plates with varying thickness, which is utilized in determining the scanning paths and the proper heating conditions. For varying thickness plates, both the in-plane membrane strain and the bending strain need to be accounted for in process design. Compared with uniform thickness plate, the required bending strain varies with not only the shape curvature but also with the plate thickness. The scanning paths are determined by considering the different weight of bending strain and in-plane strain. A thickness-dependent database is established by LF finite element analysis simulation, and the heating conditions are determined by matching the ratio of bending strain to in-plane strain between the required values and the laser forming values found in the database. The approach is validated by numerical simulation and experiments using several typical shapes.

Finite element modeling of lattice misorientations in aluminum polycrystals

Abstract Finite element simulations are used to study intracrystalline lattice misorientations in a model polycrystal. Heterogeneous deformations arise from crystal interactions and lead to irregular substructures exhibiting misorientations across their boundaries. The highest misorientations occur on interfaces that are normal to the principal loading direction.

Laser forming: Industrial applications

Laser forming is currently a laboratory technique that is beginning to see industrial applications. In this paper, we discuss practical concerns and review the progress of laser forming at GE Global Research. Two applications, 3D shape tuning and precision tube bending, are presented. Topics include considerations for industrial applications, methods for qualifying a process window, materials characterization, path planning, and system integration.Laser forming is currently a laboratory technique that is beginning to see industrial applications. In this paper, we discuss practical concerns and review the progress of laser forming at GE Global Research. Two applications, 3D shape tuning and precision tube bending, are presented. Topics include considerations for industrial applications, methods for qualifying a process window, materials characterization, path planning, and system integration.

Thermal forming process design

Thermal forming metallic components with laser energy is evolving into a viable manufacturing technology with commercial applications spanning diverse domains such as high-volume automotive part production, microelectronic device fabrication and shape tuning turbomachinery airfoils. Research activities are concentrated on quantifying the underlying mechanisms and resulting strain fields and in devising thermal forming strategies and schedules to yield a desired part shape. In this paper we outline a generalized empiric-numeric approach to determine thermal forming induced strain fields and demonstrate results with the nickel-based alloy 718, widely used in aerospace applications. The resulting strain field transfer functional is central to devising thermal forming treatments. Path planning strategies and results of thermal forming a turbomachinery compressor airfoil—a thin freeform 3D shape—are also demonstrated.Thermal forming metallic components with laser energy is evolving into a viable manufacturing technology with commercial applications spanning diverse domains such as high-volume automotive part production, microelectronic device fabrication and shape tuning turbomachinery airfoils. Research activities are concentrated on quantifying the underlying mechanisms and resulting strain fields and in devising thermal forming strategies and schedules to yield a desired part shape. In this paper we outline a generalized empiric-numeric approach to determine thermal forming induced strain fields and demonstrate results with the nickel-based alloy 718, widely used in aerospace applications. The resulting strain field transfer functional is central to devising thermal forming treatments. Path planning strategies and results of thermal forming a turbomachinery compressor airfoil—a thin freeform 3D shape—are also demonstrated.