Simulation and prediction in laser bending of silicon sheet

The laser bending of single-crystal silicon sheet （0.2 mm in thickness） was investigated with JK701 Nd：YAG laser. The models were developed to describe the beam characteristics of pulsed laser. In order to simulate the process of laser bending, the FEM software ANSYS was used to predict the heat temperature and stress-strain fields. The periodic transformation of temperature field and stress-strain distribution was analyzed during pulsed laser scanning silicon sheet. The results indicate that the mechanism of pulsed laser bending silicon is a hybrid mechanism in silicon bending, rather than a simple mechanism of TGM or BM. This work also gets silicon sheet bent after scanning 6 times with pulsed laser, and its bending angle is up to 6.5°. The simulation and prediction results reach well agreement with the verifying experiments.

Analysis of bending mechanism in multi-scanning laser bending process based on plastic strain development

By using multi-pass straight-line scan strategies,a larger bending angle can be achieved.There is,however,a limited understanding of the variation in bending angle per pass during multi-pass under various process parameters.In multi-pass laser scanning,the bending angle cannot always linearly increase with scanning passes and this phenomenon can be observed mostly in low heat input.Strain hardening is the common explanation for this phenomenon.However,it could not explain why this bending angle reduction phenomenon occurs at low heat input scanning rather than at high heat input scanning.In this study,this phenomenon is discussed based on strain development in experiments and numerical simulation.The different growing mechanism of plastic strain is analyzed to reveal the effects of laser power and scanning velocity.Furthermore,the opposite bending trend that occurred at larger laser power is discussed in comparison to the plastic strain development.The study shows that relatively larger heat input below 6.7 J/mm can help to avoid the bending angle reduction phenomenon and the opposite bending trend is highly dependent on the larger laser power.For achieving the expected cumulative bending angle in multi-pass laser bending,it is recommended to decrease the scanning velocity at a relatively low laser power level while increase the scanning velocity at a high level of laser power.

NUMERICAL SIMULATION FOR LASER BENDING OF SHEET METAL

The new flexible forming technique of sheet metal laser bending process is numerically simulated by using finite element method of large elastic plastic deformation. The temperature fields and stress strain distribution in deformation area are calculated, forming process is described and relationship between bend angle and width of sheet is discussed. It is shown that the calculated values are in good accordance with the experiments.

Deformation behavior of laser bending of circular sheet metal

The application of a thermal source in non-contact forming of sheet metal has long been used. However, the replacement of this thermal source with a laser beam promises much greater controllability of the process. This yields a process with strong potential for application in aerospace, shipbuilding, automobile, and manufacturing industries, as well as the rapid manufacturing of prototypes and adjustment of misaligned components. Forming is made possible through laser-induced non-uniform thermal stresses. In this letter, we use the geometrical transition from rectangular to circle-shaped specimen and ring-shaped specimen to observe the effect of geometry on deformation in laser forming. We conduct a series of experiments on a wide range of specimen geometries. The reasons for this behavior are also analyzed. Experimental results are compared with simulated values using the software ABAQUS. The utilization of line energy is found to be higher in the case of laser forming along linear irradiation than along curved ones. We also analyze the effect of strain hindrance. The findings of the study may be useful for the inverse problem, which involves acquiring the process parameters for a known target shape of a wide range of complex shape geometries.

The division and bending of green and red semiconductor laser light at the same time

In this experimental study, the laser light was split and bended using a specially designed glass lenses at the same time. This process has been done at the atmospheric pressure and room temperature conditions. During the experiments, the semiconductor laser as a source of green and red laser diode is used. In addition, polari- zation, magnetic field, electric field or any other auxiliary materials and systems which affect laser light are not used to bend the laser light. Only transparent glass lenses that are designed specially are used in the experimental study.