An experimental investigation of parameters effect on laser forming of Al6061-T6 sheets

Author(s):  
Amir H Roohi ◽  
H Moslemi Naeini ◽  
M Hoseinpour Gollo

Laser forming, which is categorized as a thermal forming process, is used in forming and bending of metallic and non-metallic sheets. Laser beam irradiation causes a localized temperature increase and a localized mechanical strength decrease. In this article, the effects of four process parameters, comprising laser power, scan velocity, the number of scan passes, and sheet thickness, on laser forming of Al6061-T6 sheets are studied. A design of experiment, including response surface methodology, is carried out to limit the experimental runs and costs and to identify the parameter effects on the bending angle of the sheet. Experiment results show that bending angle increases due to the decrease of scan velocity and sheet thickness. In addition, laser power and number of scan passes have a direct relation with a final sheet forming.

Author(s):  
Esmaeil Ghadiri Zahrani ◽  
Abdolali Marasi

The existence of various variables in the laser forming process brings about the implementation of two important issues of modeling and optimization to more precisely predict bending angle so as to achieve desirable conditions. In this paper, the effect of independent process parameters such as laser power, beam diameter, scan speed, sheet thickness and also the heating position on the resulted bending angle from the sheet free edge was investigated through experimentation. The results indicate different influence of parameters on the angle. Also, using response surface methodology and after conducting analysis of variance, an efficient second-order mathematical model was fit to bending angle. Consequently, with the aim of making bending angle robust in relation to possible parametric fluctuations in the process, a simultaneous optimization was carried out by use of propagation of error approach and optimal parametric combination to reach the maximum value of the angle.


2006 ◽  
Vol 129 (6) ◽  
pp. 1035-1044 ◽  
Author(s):  
A. J. Birnbaum ◽  
P. Cheng ◽  
Y. L. Yao

Although considerable effort has gone into characterizing the laser forming process in terms of process parameters and conditions, there has been little emphasis on the effects of the mechanical and thermal constraints introduced by the clamping method utilized for a desired application. This research suggests means for investigating and predicting the resulting geometry of a specimen due to laser operation in close proximity to an array of imposed thermo-mechanical constraints for both the single and multiple scan cases; specifically, the resulting average bending angle as well as bending angle variations throughout the part. This is accomplished by initially only considering these effects on the thermal field. Conclusions are then drawn about the nature of the mechanical effects. These conclusions are validated through numerical simulation as well as physical experimentation. An analytical solution of the thermal problem is also presented for further validation of the temperature field as a constrained edge is approached.


2007 ◽  
Vol 329 ◽  
pp. 625-630 ◽  
Author(s):  
Koichi Okuda ◽  
Y. Sugie ◽  
Masayuki Nunobiki

This study deals with behaviour of bending deformation in CO2 laser forming process of titanium. CO2 laser forming technique was applied for a pure titanium plate with thickness of 1 mm to aim the development of new bending process. The experiments of laser forming were carried out with a CO2 laser machine. The bending angle and the temperature of workpiece were examined under the condition of various laser power, feed speed and laser spot diameter. Based on the experimental results, it was found that the bending deformation behaved greatly depending on the laser power and the laser spot diameter. The bending angle increased with an increase in the laser power. The bending direction tended to change from the laser irradiation side to its opposite side when the large laser spot diameter was applied.


Metals ◽  
2019 ◽  
Vol 10 (1) ◽  
pp. 17 ◽  
Author(s):  
Herman Fidder ◽  
Joris P. J. Admiraal ◽  
Václav Ocelík ◽  
Jeff Th. M. De Hosson

In this study experimental and modelling methods are used to examine the microstructural and bending responses of laser-formed commercially pure titanium grade 2. The in situ bending angle response is measured for different processing parameters utilizing 3D digital image correlation. The microstructural changes are observed using electron backscatter diffraction. Finite element modelling is used to analyse the heat transfer and temperature field inside the material. It has been proven that the laser bending process is not only controlled by processing parameters such as laser power and laser beam scanning speed, but also by surface absorption. Grain size appears to have no influence on the final bending angle, however, sandblasted samples showed a considerably higher final bending angle. Experimental and simulation results suggest that the laser power has a larger influence on the final bending angle than that of the laser transverse speed. The microstructure of the laser heat-affected zone consists of small refined grains at the top layer followed by large elongated grains. Deformation mechanisms such as slip and twinning were observed in the heat-affected zone, where their distribution depends on particular processing parameters.


Author(s):  
Mohammad Shahid Raza ◽  
Talari Srinu ◽  
Susmita Datta ◽  
Partha Saha

The present study provides detailed investigation on the effect of various laser processing parameters and scan strategy during laser forming of thin open-celled aluminium foam. Previous research on laser bending showed that metal foams can be formed by laser processing, but it is very difficult to form the metal foams mechanically owing to their brittle nature. The 2D Laser forming operation was carried out using 2 kW fiber laser with laser power and scanning speed as input process parameters while bending angle was calculated as an output parameter. The effect of laser power, scan speed, number of scans and scan distance from the edge on bending angle of the foam were analyzed and presented. It was observed that the laser processing showed a decrease in bending angle with an increase in scan speed except for 1750 W power, where after 12500 mm/min the bending angle did not follow the trend. The bending angle decreased with increase in number of scans probably due to strain hardening effect. The effect of scan distance from the edge was different for lower process parameter combinations {600 W, 2500 mm/min} and {1000 W, 4000 mm/min}, where the bending angle was maximum for a distance of 20 mm from edge in 1400 W, 7500 mm/min scan speed. For 1750W, 11000 mm/min bending angle was maximum for 80 mm distance from edge. The SEM analysis showed that the major concern associated with laser forming of open-celled Aluminium foam is foam melting. EDS and XRD analysis showed that formation of different oxides and compounds of Aluminium increases with increases in laser power and scan speed. Micro-Computed Tomography (micro-CT) analysis confirmed the absence of crack during laser forming and the pore density variation during laser forming was clearly visible between laser processed zone and the parent material zone.


2008 ◽  
Vol 575-578 ◽  
pp. 408-415
Author(s):  
Jie Liu ◽  
Yan Jin Guan ◽  
Sheng Sun ◽  
Guang Chun Wang

There are many factors, such as the laser and geometrical parameters, which influence greatly on the laser bending process. So it is of great importance to determine these variables properly. Considering the relationship of material properties and temperature, a 3-D thermal-mechanical finite element analysis model for laser micro-bending of stainless steel foil is developed based on the software MSC.Marc, and the laser micro-bending process of 0.1mm thick stainless steel foil is implemented. The finite element method simulation process is integrated with the optimization software package iSIGHT through secondary development. The objective function is to realize the maximum bending angle after single laser scan, and laser power, beam diameter and scanning velocity are regarded as the design variables. The forming process is optimized by using genetic algorithm. The optimal result shows the bending angle can be got to the maximum 1.0332°when the laser power, beam diameter and scanning velocity are 32W, 0.17mm and 132mm/s respectively. The experiment results are in good agreement with optimal results.


2007 ◽  
Vol 344 ◽  
pp. 243-250
Author(s):  
Masaaki Otsu ◽  
Yasuhiro Ito ◽  
Akira Ishii ◽  
Hideshi Miura ◽  
Kazuki Takashima

Pure titanium foils were bent by laser forming and the effect of c-d transformation and history of heat treatment of specimen on bending angle was investigated. The thickness of specimens was changed from 40 to 100om, the length of them was 20mm and the width of them was 10mm. The specimens were annealed at 600-1100oC for 30 minutes in argon atmosphere. A 20W YVO4 laser was employed and laser power was changed from 2 to 16W. From the experimental results, when laser power was increased, bending angle also increased and it was dramatically changed at the laser powers occurring c-d transformation and melting. Bending angle increased as grain size increased and it jumped up when grain size exceeded the foil thickness and then became constant. Bending angle decreased by annealing after forming and degree of decrease was greater when the annealing temperature before forming was lower.


2012 ◽  
Vol 504-506 ◽  
pp. 1213-1218 ◽  
Author(s):  
Loredana Santo ◽  
Denise Bellisario ◽  
Ludovica Rovatti ◽  
Fabrizio Quadrini

Laser forming tests have been performed on open-cell aluminum alloy foams with different pore size. Laser power was fixed at 150 W, a total of 150 laser scans led to a bending angle up to 60°, depending on the laser scan rate. At the end of the laser bending, the foams were left to cool and samples were extracted for analysis by means of an optic microscope. The alloy microstructure was investigated in different points of the samples and correlated with the processing conditions. Image analysis was also carried out to extract the percentage of melted area due to laser heating.


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