This method has broad applications for the repairing, cladding and manufacturing of engineering components and artistic pieces.
However, due to the complicated thermal history of laser-based AM processes, uneven thermal contraction and expansion occur, which generate a massive amount of residual stress inside the solidified material.
The stress distribution obtained through online monitoring is similar to that from the traditional thermal-stress simulation.
Laser-aided metallic additive manufacturing uses a laser as a heat source to melt the substrate, deliver metal powder into the melt pool coaxially, and deposit it on the substrate to form various shapes required by the user.
Based on computer vision and FEM analysis, this method can make a quick prediction of the stress generated during the laser deposition process. B is the shape of the molten pool when it just forms.
At this time, the material is in a liquid state; although it contains certain forces and stresses in it, such properties are negligible compared to those of the solid state.
Currently, the most common methods are simulation and postmortem stress examination.
The numerical simulation begins with pure temperature calculation, through 2D to 3D models added solidification phase changes to the model to make the result more closely resemble the experimental data. Moat uses X-ray diffraction to measure the residual stress in Co-based laser clad layers.
However, this method cannot directly reflect the real condition inside the deposition layer. Biegler applied digital image correlation (DIC) technology to measure the distortion on the substrate.
This method must spray a cover layer on the target area, which makes it easier to detect the distortion.