Laser forming process of complex surface on Al7075

Author(s):  
Xiaogang Wang ◽  
Yongjun Shi ◽  
Yankuo Guo ◽  
Xianfa Li ◽  
Xiaoyu Zhao
2002 ◽  
Vol 124 (2) ◽  
pp. 379-388 ◽  
Author(s):  
Jin Cheng ◽  
Y. Lawrence Yao

Laser forming of steel is a hot forming process with high heating and cooling rate, during which strain hardening, dynamic recrystallization, and phase transformation take place. Numerical models considering strain rate and temperature effects only usually give unsatisfactory results when applied to multiscan laser forming operations. This is mainly due to the inadequate constitutive models employed to describe the hot flow behavior. In this work, this limitation is overcome by considering the effects of microstructure change on the flow stress in laser forming processes of low carbon steel. The incorporation of such flow stress models with thermal mechanical FEM simulation increases numerical model accuracy in predicting geometry change and mechanical properties.


2008 ◽  
Vol 375-376 ◽  
pp. 333-337
Author(s):  
Li Jun Yang ◽  
Yang Wang

Laser forming of metal sheet is a forming technology of sheet without a die that the sheet is deformed by internal thermal stress induced by partially irradiation of a laser beam. In this paper, the bending behavior of common stainless steel 1Cr18Ni9 sheet is studied after being irradiated by straight line with a Nd:YAG pulsed laser beam. The aim of the investigation is to find out the relationship of the physical behaviors of heat affected zone (HAZ) with the pulse parameters of the laser. Through the analysis of the fundamental theory of pulsed laser affected, this paper shows the affected characteristics of metal sheet with pulsed laser forming. The results show that the microstructure of HAZ of pulsed laser scanned is layered, and the micro-hardness is improved than that in matrix. The microstructures show that the deformed grain structure is inhomogeneous, that caused the grain sizes and grain orientations in HAZ to become different. By qualitative analysis of experimental result, the conclusion obtained may provide basis for theoretical investigation and possible industrial application of laser forming process in the future.


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.


2011 ◽  
Vol 49 (9-10) ◽  
pp. 1101-1110 ◽  
Author(s):  
Z.L. Lu ◽  
D.C. Li ◽  
Z.Q. Tong ◽  
Q.P. Lu ◽  
M.M. Traore ◽  
...  

Author(s):  
Wei Shen ◽  
Renjun Yan ◽  
Shuangying Li

Ship hull structures are fabricated by curved thick plates before they are welded together. There are traditional methods such as, line heating and laser-forming methods for plate bending. However, it is recognized that the hot-forming technology causes a series of troubles on doubly or multiple curved plates. Multi-point forming mechanism with square press heads is a new forming process for three-dimensional ship hull plate. Cold-forming has a high dimensional accuracy but results in spring-back. The spring-back process of curved thick plates in the finite element method is analyzed and the predicted results are compared with the test results in the present paper. To ensure the forming precision, the successive approximation method is also developed and verified to control the spring-back.


2019 ◽  
Vol 969 ◽  
pp. 552-557
Author(s):  
Kuntal Maji

Fabricating three dimensional shaped surfaces from flat sheet metals by laser forming, both out-of-plane and in-plane deformations are required. This article presents the modeling of coupling mechanism activated laser forming of sheet metals based on experimental data for prediction and optimization of bending and thickening deformations. Experiments were performed based on a central composite design of experiments on coupling mechanism based laser metal forming process considering the input process parameters like laser power, scan speed and spot diameter, bending and thickening were taken as the outputs. Neural network and neuro-fuzzy system-based models were developed to carry out both forward and inverse modeling of the laser metal forming process under the coupling mechanism. Multi-objective optimization based on the non-dominated sorting genetic algorithm was used to obtain multiple optimal solutions to achieve different amounts of out-of-plane and in-plane deformations. The proposed method could guide for a suitable selection of the process parameters to produce three-dimensional shapes utilizing coupling mechanism-based laser forming using multiple laser line heating.


2010 ◽  
Vol 139-141 ◽  
pp. 634-638 ◽  
Author(s):  
Biao Tang ◽  
Yong Tang ◽  
Rui Zhou ◽  
Zhen Ping Wan

To meet the increasing application requirements of stainless steel fibers with rough surface morphology, a self-made multi-tooth tool which can bifurcate chip during the cutting process was utilized to manufacture stainless steel fibers. The novel cutting method can achieve efficient processing of continuous stainless steel fibers with complex surface morphology. The influence of cutting parameters (back engagement ap and feed rate f ) on forming process of fibers’ surface morphology was studied. The cutting experiments were carried out under the condition of selected tool and fixed workpiece rotating speed. The results show that: the surface morphology of stainless steel fiber is simultaneously effected by ap,and feed rate f .Between them, ap has more significant effect on it. In order to obtain stainless steel continuous fibers with coarse surface morphology, the optimum cutting parameters were recommended as follows: ap∈(0.1-0.2) mm, f ∈(0.1 -0.17) mm/r.


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