Experimental Investigation on Formability of Cryorolled and Room Temperature Rolled AA 6061 Sheet Metal with 50% and 75% Thickness Reduction

2014 ◽  
Vol 592-594 ◽  
pp. 302-306 ◽  
Author(s):  
Tinu P. Saju
Keyword(s):  
Experimental Investigation ◽  
Sheet Metal ◽  
Cryogenic Temperature ◽  
Room Temperature ◽  
Forming Limit Diagram ◽  
Thickness Reduction ◽  
Forming Limit ◽  
Forming Limit Diagrams ◽  
Short Annealing ◽  
Clear Idea

This paper deals with the formability of AA 6061 sheet metal. The forming limit diagram of precipitation hardenable Al–Mg–Si alloy namely AA 6061 was evaluated for sheets rolled at two different temperature media namely room temperature and cryogenic temperature. The sheets were subjected to solutionising, rolling either in room temperature or cryogenic temperature with 50% or 75% reduction and short annealing before forming operation. The forming limit diagrams of the rolled sheets were plotted together to obtain a clear idea about their comparative formability.

Research on the Forming Limit Diagram Based on Laser Shock Forming

2010 ◽  
Vol 44-47 ◽  
pp. 148-152
Author(s):  
Yin Fang Jiang ◽  
Zhen Zhou Tang ◽  
Zhi Fei Li ◽  
Lei Fang
Keyword(s):  
Sheet Metal ◽  
Strain Path ◽  
Reduction Rate ◽  
Forming Limit Diagram ◽  
Thickness Reduction ◽  
Forming Limit ◽  
Laser Shock ◽  
Maximum Thickness ◽  
Laser Shock Forming ◽  
Strain Paths

Laser shock forming (LSF) of sheet metal is a novel technology in plastic deformation. It is necessary to correctly predict the Forming Limit Diagram (FLD) based on LSF. New failure maximum thickness reduction rate criterion is used to determine the forming limit based on the numerical system during LSF. The relationship model between maximum thickness reduction rate and the strain path is built. In addition, the effects of strain path and strain-hardening exponent on forming limit are considered. The maximum thickness reduction rate under equi-biaxial tensile strain path can be determined easily during LSF and the expression of the criterion is determined finally. Then the limit strains under other strain paths between uniaxial tension to equi-biaxial tension can be determined by the criterion combined with numerical simulation of forming process. The criterion can predict forming limits for sheet metal exactly and makes it possible to determine forming limit strains under different strain paths only through equi-biaxial tensile test during LSF.

Optimization of Sheet Metal Process Parameters of a Shield Case Piece Using Computer Simulation

2006 ◽  
Vol 510-511 ◽  
pp. 330-333
Author(s):  
M.C. Curiel ◽  
Ho Sung Aum ◽  
Joaquín Lira-Olivares
Keyword(s):  
Sheet Metal ◽  
Thickness Distribution ◽  
Forming Limit Diagram ◽  
Forming Limit ◽  
Physical Processes ◽  
Forming Process ◽  
Element Analysis ◽  
One Step ◽  
Range Of Values ◽  
Principal Strains

Numerical simulations based on Finite Element Analysis (FEA) are widely used to predict and evaluate the forming parameters before performing the physical processes. In the sheet metal industry, there are basically two types of FE programs: the inverse (one-step) programs and the incremental programs. In the present paper, the forming process of the shield case piece (LTA260W1-L05) was optimized by performing simulations with both types of software. The main analyzed parameter was the blankholding force while the rest of the parameters were kept constant. The criteria used to determine the optimum value was based on the Forming Limit Diagram (FLD), fracture and wrinkling of the material, thickness distribution, and the principal strains obtained. It was found that the holding force during the forming process deeply affects the results, and a range of values was established in which the process is assumed to give a good quality piece.

Incremental Sheet Forming with an Industrial Robot – Forming Limits and Their Effect on Component Design

2005 ◽  
Vol 6-8 ◽  
pp. 457-464 ◽  
Author(s):  
L. Lamminen
Keyword(s):  
Sheet Metal ◽  
Industrial Robot ◽  
Forming Limit Diagram ◽  
Sheet Forming ◽  
Incremental Sheet Forming ◽  
Point Of View ◽  
Forming Limit ◽  
Forming Process ◽  
3D Cad ◽  
Component Design

Incremental sheet forming (ISF) has been a subject of research for many research groups before. However, all of the published results so far have been related to either commercial ISF machines or ISF forming with NC mills or similar. The research reported in this paper concentrates on incremental sheet forming with an industrial robot. The test equipment is based on a strong arm robot and a moving forming table, where a sheet metal blank is attached. The tool slides on the surface of the sheet and forms it incrementally to the desired shape. The robot is capable of 5-axis forming, which enables forming of inwards curved forms. In this paper the forming limit diagram (FLD) for ISF with the robot is presented and it is compared with conventional forming limit diagrams. It will be shown that the conventional FLD does not apply to incremental forming process. Geometrical accuracy of sample pieces is also studied. Cones of different shapes are formed with the robot equipment and their correspondence with the 3D CAD model is evaluated. The results are compared with other results of accuracy of incremental sheet forming, reported earlier by other researchers. The third issue covered in this article is a product development point of view to incremental sheet forming. In addition to fast prototyping and low volume production of sheet metal parts, ISF brings new possibilities to sheet metal component design and manufacturing. These possibilities can only be exploited if design rules, that will take the possibilities and limitations of the method into account are created for ISF.

Influence of Pre-Forming on the Forming Limit Diagram of Aluminum and Steel Sheets

2007 ◽  
Vol 344 ◽  
pp. 113-118 ◽  
Author(s):  
Massimo Tolazzi ◽  
Marion Merklein
Keyword(s):  
Dual Phase Steel ◽  
Process Analysis ◽  
Forming Limit Diagram ◽  
Forming Limit ◽  
Linear Strain ◽  
Forming Limit Diagrams ◽  
Steel Sheets ◽  
Biaxial Stretching ◽  
Strain Paths

This paper presents a method for the experimental determination of forming limit diagrams under non linear strain paths. The method consists in pre-forming the sheets under two different strain conditions: uniaxial and biaxial, and then stretching the samples, cut out of the preformed sheets, using a Nakajima testing setup. The optical deformation measurement system used for the process analysis (ARAMIS, Company GOM) allows to record and to analyze the strain distribution very precisely with respect to both time and space. As a reference also the FLDs of the investigated grades (the deep drawing steel DC04, the dual phase steel DP450 and the aluminum alloy AA5754) in as-received conditions were determined. The results show as expected an influence of the pre-forming conditions on the forming limit of the materials, with an increased formability in the case of biaxial stretching after uniaxial pre-forming and a reduced formability for uniaxial load after biaxial stretching if compared to the case of linear strain paths. These effects can be observed for all the investigated materials and can be also described in terms of a shifting of the FLD, which is related to the art and magnitude of the pre-deformation.

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