Deep Drawing

Aluminum alloys have a high strength-to-weight ratio and proper anti-corrosion properties that are used in the automotive, shipbuilding and aerospace industries. The major problem with forming aluminum sheets is the low formability of aluminum sheets at room temperature. Therefore, in the present study, warm deep drawing (WDD) of AA5052-O aluminum alloy sheets with a thickness of 1mm was investigated at the different forming temperatures of 25, 80, 160, and 240°C (in the two isothermal and nonisothermal conditions) and punch speeds of 260, 560 and 1950 mm min-1 using experimental tests and finite elements simulation. The finite element simulation predictions show a good agreement with the experimental data. The results showed that an increase in forming temperature and a decrease in forming speed led to a decrease in forming force and an increase in cup height. Additionally, a microstructural and experimental investigation showed that the fracture of the cup corner radii occurs in th...

SUMMARY: Springback is one of the major causes for fabrication parts rejection in sheet metal forming. This is a geometrical defect that occurs on the drawn part after removing all the stamping tools, and is caused by elastic strain recovery of the material. In this work, springback is evaluated with a benchmark test that consists on cutting a ring specimen from a drawn cup and then splitting it longitudinally along a radial plan. Numerical simulation results were obtained using the finite element code DD3IMP with the package DD3TRIM to perform the ring cuts and splitting. Finite element mesh sensitivity tests were done and results were post-processed with GID software.

Blank design is an important task in sheet metal forming process optimization. The initial blank shape has direct effect on the part quality. This paper presents a deformation based blank design approach to determine the initial blank shape for a formed part. The blank design approach is integrated separately into ABAQUS, and DD3IMP, a research purpose in-house FEA code, to

We use a texture component crystal plasticity finite element method for the simulation of plane strain compression (maximum thickness reduction 95%) of a ferritic stainless steel (X6Cr17, AISI 430, 1.4016). The method incorporates the graded hot band texture of the starting material and predicts the development of the orientation distribution during forming in the surface and in the center layer considering 24 slip systems.

Optimization of process parameters in sheet metal forming is an important task to reduce manufacturing cost. To determine the optimum values of the process parameters, it is essential to find their influence on the deformation behaviour of the sheet metal. The significance of three important process parameters namely, die radius, blank holder force and friction coefficient on the deep-drawing characteristics of a stainless steel axi-symmetric cup was determined. Finite element method combined with Taguchi technique form a refined predictive tool to determine the influence of forming process parameters. The Taguchi method was employed to identify the relative influence of each process parameter considered in this study. A reduced set of finite element simulations were carried out as per the Taguchi orthogonal array. Based on the predicted thickness distribution of the deep drawn circular cup and analysis of variance test, it is evident that die radius has the greatest influence on the deep drawing of stainless steel blank sheet followed by the blank holder force and the friction coefficient. Further, it is shown that a blank holder force application and local lubrication scheme improved the quality of the formed part.

Improving the drawing limits of the material is an important issue, especially when forming materials with limited formability. Heating the material up to a temperature where the yield strength decreases and formability increases drastically is one proper option to improve the drawing limit. This requires a considerable amount of energy and also might cause the material lose its character. An alternative to improve the forming limits is to heat only the flange region to a lower temperature in the warm region - decreasing the flow curve and increasing formability just enough and in the end of the process the material character is not affected or this effect can be considered negligible. In this study, a numerical basis for improving the drawing limits of one such material, DP600, is studied. For this, first, a finite element simulation for the heating up of the flange region is studied, followed by the simulation of the deep drawing process. The results of both heating simulation and the deformation are compared with the experimental studies and a good correlation has been found. It is also found that it is possible to increase the drawing limit of a DP600 steel sheet through the process of heating of the flange region.

In the current paper, numerical results of cylindrical cup drawing of aluminum-lithium sheets using the commercial software abaqus/explicit are presented. This software permits investigating physical models of real procedures putting singular emphasis on geometrical non-linearities produced by large deformations, material properties and complex conditions. Numerical simulation using finite element methods (fem) offers the ability of analysing the feasibility of a process, allowing the benefit of saving time and reducing costs by comparison with traditional methods. The 2090 t3 aluminum-lithium alloy was studied with the focus on the influencing plastic anisotropy that affect the final predicted part. The results illustrate that anisotropy influence the thickness variation, and a comparison between anisotropic and isotropic yield was discussed.

Sheet metal forming of tribologically difficult materials such as stainless steel, Al-alloys and Ti-alloys or forming in tribologically difficult operations like ironing, punching or deep drawing of thick plate requires often use of environmentally hazardous lubricants such as chlorinated paraffin oils in order to avoid galling. The present paper describes a systematic research in the development of new, environmentally harmless lubricants focusing on the lubricant testing aspects. A system of laboratory tests has been developed to study the lubricant performance under the very varied conditions appearing in different sheet forming operations such as stretch forming, deep drawing, ironing and punching. The laboratory tests have been especially designed to model the conditions in industrial production. Application of the tests for evaluating new lubricants before introducing them in production has proven successful and has in a number of examples assisted the substitution of environmentally hazardous lubricants by more friendly ones in industrial production.

A texture component crystal plasticity finite element method (TCCP-FEM) is used for the simulation of cup drawing of a ferritic stainless steel sheet (X6Cr17, AISI 430, EN 1.4016). The simulation includes the through-thickness texture gradient of the starting hot band. It predicts the development of the orientation distribution and the earing profile during cup forming considering 48 slip systems (12{1 1¯ 0}〈1 1 1〉, 12{1 1 2¯}〈1 1 1〉, 24{123¯}〈1 1 1〉). The earing profiles are compared to FE results obtained by use of a Hill 48 yield surface and to experimental data.

Deep drawing of sheet metal is one of the most important transformation's process in which a sheet metal blank is drawn into a forming die via a punch force. The conventional deep drawing of sheet metal techniques, known for their wide usage in several industry sectors, are experimental and expensive processes. Numerical simulation using Finite Element Methods (FEM) offers the ability of analyzing the feasibility of a process, allowing the benefit of saving time and considerably reducing costs by comparison with traditional methods. This virtual simulation requires the realization of the tools and their adjustment according to the resulting data till seizing a satisfactory adequacy of results. In this study, a Hill48 anisotropic yield criterion was adopted to express the mechanical material properties using ABAQUS/EXPLICIT software. A finite element model is developed for the 3D numerical simulation of sheet metal deep drawing process. Two aluminum alloys AA1050 and AA1100, were studied with the focus on the influencing parameters involving both physical and material properties that affect the final predicted part. The developed model predicts the thickness and the formation of ears of the blank based on plastic Hill yield criteria. The earring prediction was simulated using extra deep drawing.

Deep drawing is part of forming process in which sheet metal drawn into die cavity by action of a punch. Sheet metal drawing is a more complex operation than cutting or bending, and more things can go wrong. A blank holding force, punch force, material property of sheet metal, thickness of sheet, velocity of punch, these are all affecting parameters in deep drawing process to regulate wrinkling effect, tearing effect and fracture defect. Nowadays composite material is extensively used in manufacturing industries due to its better strength. Die radius has the greatest influence on the deep drawing of stainless steel blank sheet followed by the blank holder force and the friction coefficient. Further, it is shown that a blank holder force application and local lubrication scheme improved the quality of the formed part. The present study aims to determine the optimum blank shape design for deep drawing of arbitrary shaped cups with a uniform trim allowance at the flange, i.e., cups without ears. The earing, or non-uniform flange, is caused by non-uniform material flow and planar anisotropy in the sheet. Drawing is sheet metal forming operation used to make cup shaped, box shaped, and complex curved and concave cup.

Micro flexible tool-assisted sheet metal forming is one of the forming techniques that have increasingly attracted extensive attention of researchers. Due to its simplicity, low overall production cost, feasibility of prototyping, this forming process seems appropriate for producing micro components. This work presents an evaluation study on using flexible deep drawing process to produce micro stainless steel 304 square cups. The influence of initial foil thickness and blank shape are investigated in details. An optimization of blank shape is implemented to provide micro square products with net-shape and flange free. The finite element simulations are achieved using the commercial code Abaqus/Standard. The results showed that the initial foil thickness affects the thinning and thickening values of the formed cup wall. As well as, the optimization method is feasible to indicate the optimum initial blank shape for producing free flange-micro square parts.

In this paper, the formability of two-layer (aluminum-st12 steel) sheets in the deep drawing process was investigated through numerical simulations and experiments. The purpose of this research was to obtain more formability in deep drawing process. The limit drawing ratio (LDR) was obtained in deep drawing of two-layer metallic sheets, with aluminum inner layer which was in contact with the punch and steel outer layer which was in contact with the die. Finite element simulations were performed to study the effect of parameters such as the thickness of each layer, value of die arc radius, friction coefficient between blank and punch, friction coefficient between blank and die, and lay-up on the LDR. Experiments were conducted to verify the finite element simulations. The results indicated that the LDR was dependent on the mentioned parameters, so the LDR and as a result the two-layer metallic sheet formability could be increased by improvement of these parameters in deep drawing process.

Purpose: This paper deals with the FEA of the sheet metal forming process that involves various nonlinearities. Our objective is to develop a parametric study that can leads mainly to predict accurately the final geometry of the sheet blank and the distribution of strains and stresses and also to control various forming defects, such as thinning as well as parameters

Deep drawing process is an important sheet metal forming in which flat sheet metal had been forced through
the die in association with the forward punch force and opposing blankholder force. As the blank passes through the
tool set converts 2D bank into 3D cup form. The process of achieving the required diameter of the cup can be
produced in single stage or multistage operation. In this study, experimental study had been conducted on single stage
deep drawing process for assessment of radial strain, circumferential strain and thickness variation in aluminum
alloyAA6061. Cylindrical cup deep drawing experimental tests were performed with blank of 350 mm diameter of
0.953mm thickness sheet. It has been found that deeper cups were produced by selecting the optimum design
parameters and the results are in good agreement with simulation results found form literature.

The aim of use blankholder gap (BHG) is to regulate the flow of material in the
cavity of the die. In this paper, the effect of blankholder gap on parameters of process
such as forming load, strains and stress distributions and occurrence of wrinkling in
the cup wall were analyzed numerically. Finding thebest BH gap for the die and the
material which use in this study. Different values of (BHG) to arrange (0.5 -3 mm)
were used and also without (BHG). 3D model of deep drawing was used and analyzed
based on FEM. The best forming distance for the blankholder is between 1 to 1.5
times sheet thickness. The results showed that when the gap is larger than 0.75 mm,
the wrinkles will occur and the drawing force increased.

Lightweight design is essential for an economic and environmentally friendly vehicle. Aluminium sheet metal is well known for its ability to improve the strength to weight ratio of lightweight structures. One disadvantage of aluminium is that it is less formable than steel. Therefore complex part geometries can only be realized by expensive multi-step production processes. One method for overcoming this

Deep drawing of non-axisymmetric cross-section cups from thin sheets or metal foils has become increasingly important, especially for miniaturization of mechanical components. However, with a thin sheet thickness, conventional deep drawing processes are not able to offer reasonable drawing ratios due to early formations of localized wrinkling and fractures at cup corners. In this paper, a friction aided deep drawing process has been developed to increase the deep drawability of thin sheets and metal foils. Productions of square cups have been chosen to verify the current proposed process since the shape provides recognizable non-homogeneous deformation, which can then be compared to conventional processes. In the proposed process, a circular blank holder of a square hole is divided into eight identical segments of 45-. During the deep drawing process, four of the eight segments will move radially inward while the other four segments will move radially outwards cyclically under a pre-determined blank holding pressure. A finite element model of the technique was used to simulate virtual experiments to evaluate and optimize the controlling parameters that influence the cup height and forming process. Taguchi and Pareto ANOVA statistical methods were subsequently used to determine the optimum conditions for best cup height. The results have shown that the new technique is capable of producing deep square cups from soft aluminum sheet (Al-O) of 0.5 mm thickness with a high drawing ratio of 3.3. In addition, it was also observed that the radial displacement was the most significant parameter in influencing the cup height. (C) 2011 Elsevier B.V. All rights reserved.

http://www.sciencedirect.com/science/article/pii/S0924013611002743

One of the major problems in forming of stainless steel sheet is galling due to lubricant film breakdown leading to scoring and bad surface quality. In a Danish research programme new lubricants substituting the normally applied chlorinated paraffin oils are being developed and tested for this purpose. In order to determine the limits of lubrication of these new lubricants, as well as commercial ones already available on the market, two sheet forming tests have been developed. Quantification of the degree of galling is done by roughness measurements on the workpiece surface. In a strip reduction test, this is done by 2D profilometry at strip locations corresponding to different sliding lengths, whereas a deep drawing test is based on 3D roughness mapping of local areas.

The quality of the drawn part is highly required during deep drawing process, moreover, the control of physical and geometrical parameters is mandatory to reduce defects. Friction is one of the significant geometrical parameters which influences the drawn shapes. This research goals to predict the friction behavior of AA2090 Al-Li alloy in three different regions of a cylindrical deep drawing: between blank surface and punch, blank surface and die, and blank surface and blank holder. For this purpose, thickness distribution has been studied using a 3D cylindrical deep drawing model, simulated by ABAQUS finite element software. A combination between finite element model and parametric optimization of Taguchi method was carried out. Thickness variation has been studied, and the region of the minimum thickness has been analyzed, the results obtained from finite element analysis were used as inputs of Taguchi method to identify the most appropriate combination of the Coulomb friction in the three regions concerning AA2090 Al-Li alloy.

Deep drawing is one of the most used sheet metal forming processes in the production of automotive components, LPG bottles and household goods, among others. The formability of a blank depends on the process parameters such as blank holder force, lubrication, punch and die radii, die-punch clearance, in addition to material properties and thickness of the sheet metal. This paper presents a numerical study made on the deep drawing of LPG bottles. In particular, the application of both variable blank holder forces and contact friction conditions at specific location during deep drawing are considered. The numerical simulations were carried out with DD3IMP FE code. A variable blank holder force strategy was applied and the numerical results were compared with results from other blank holder force schemes. It is evident that the proposed variable blank holder force scheme reduces the blank thinning when compared to other schemes; the friction coefficient also has a significant influence on the stress–strain distribution.

Tailor-welded blanks made of dissimilar, uniform or non-uniform thickness materials have potential applications in automobile industries. Compared to the base metal, the formability of tailor-welded blank is less due to the presence of weld area and strength mismatch between component blanks. Most sheet metals used to produce tailor-welded blanks have anisotropy induced during pre-processing stage due to large deformation. The orientation of the blank sheet rolling direction and the combination of the blank sheet materials has significant influence on the deformation behaviour. The effect of anisotropy in the tailor-welded blank and the orientation of blank sheets rolling direction during deep-drawing process are investigated in this study. Finite element analysis of deep-drawing mild steel and dual-phase steel tailor-welded blank models was carried out using research purpose FE code DD3IMP; to form a basis for tailor-welded blank design and development for a part. Anisotropy in the blank sheets has moderate influence and its contribution to increased material flow depends on the mechanical properties of the blank sheets. Appropriate combination of the blank sheets rolling direction orientation can significantly improve the formability of the tailor-welded blank in the deep-drawing of square cup.