scholarly journals Forming limit of sheet metal in cylindrical deep drawing with a conical die

2020 ◽  
Vol 967 ◽  
pp. 012087
Author(s):  
Luo Xin ◽  
C A Evsyukov ◽  
Yu Zhongqi
Keyword(s):  
Sheet Metal ◽  
Deep Drawing ◽  
Forming Limit ◽  
Conical Die

Formability Improvement Technique for Heated Sheet Metal Forming by Partial Cooling

2014 ◽  
Vol 622-623 ◽  
pp. 279-283 ◽  
Author(s):  
Eiichi Ota ◽  
Yasuhiro Yogo ◽  
Takamichi Iwata ◽  
Noritoshi Iwata ◽  
Kenjiro Ishida ◽  
...  
Keyword(s):  
Temperature Distribution ◽  
Sheet Metal ◽  
Deep Drawing ◽  
Initial Temperature ◽  
Hot Stamping ◽  
Local Deformation ◽  
Control Technique ◽  
Forming Limit ◽  
Forming Process ◽  
Initial Temperature Distribution

A forming process for heated sheet metal, such as hot-stamping, has limited use in deformable shapes. Higher temperature areas which have not yet come into contact with dies are more easily deformed; therefore, local deformation occurs at these areas which leads to breakage. To improve the formability of heated sheet metal, a deformation control technique utilizing the temperature dependence of flow stress is proposed. This technique can suppress local deformation by partial cooling around potential cracking areas to harden them before forming. In order to apply this technique to a variety of product shapes, a procedure to determine a suitable initial temperature distribution for deep drawing and biaxial stretching was developed with a coupled thermal structural simulation. In this procedure, finite elements exceeding forming limit strain are highlighted, and an initial temperature distribution is defined with areas of decreased temperature around the elements to increase their resistance to deformation. Subsequently, the partial cooling technique was applied to a deep drawing test with a heated steel sheet. The results of the experiment showed that the proposed technique improved 71% in the forming limit depth compared with results obtained using a uniform initial temperature distribution.

Analysis and Correction of Defects for Deep Drawing Process of Stainless Sink by Use of Finite Element Simulation

2021 ◽  
Vol 889 ◽  
pp. 153-159
Author(s):  
Benjaphorn Khuanngern ◽  
Surasak Suranuntchai
Keyword(s):  
Finite Element ◽  
Stainless Steel ◽  
Sheet Metal ◽  
Deep Drawing ◽  
Forming Limit Diagram ◽  
Yield Function ◽  
Production Quality ◽  
Die Design ◽  
Forming Limit ◽  
High Production Cost

Finite Element Method (FEM) becomes one of the most useful techniques to analyze problems in sheet metal forming processes because of this technique can reduce cost and time in die design and trial step [1]. This research was aimed to predict the optimal parameters in order to eliminate cracks and wrinkles on stainless steel sink product under deep drawing named “DLS50”. The material was made from Stainless Steel 304 with thickness 0.6 mm. The parameters that had been investigated were punch angle and velocity as well as pressure of the punch. In order to simplify the process, punch and die in the simulation were assumed to be a rigid body, which neglected the small effect of elastic deformation. The properties of stainless steel sheet was assumed to be anisotropic, behaved according to constitutive equation of power law and deformed elastic-viscoplastic, which followed Barlat 3 components yield function. The deformation for Forming Limit Diagram (FLD) was predicted by the Keeler equation. Most of the defects such as cracks and wrinkles were found during the process on the parts. In the past, practical productions were performed by trial and error, which involved high production cost, long lead time, and wasted materials. From the prediction results, decreasing punch velocity from 50 mm/s to 8.33 mm/s would reduce the blank shearing zone on the corner bottom of the part and remove cracks in the process. The performing of the stainless sink by decreasing pressure in the process from 2.3 bar to 2 bar, and adjusting the punch shape increasing 5 mm. each side would increase formability of sheet metal in all direction, the reduction of cracking tendency zone out of the part. In conclusion by using the simulation technique, the production quality and performance had been improved.

Research on Box Drawing Coefficient of Friction Based on Dynaform

2012 ◽  
Vol 628 ◽  
pp. 223-228
Author(s):  
Zhi Gao Luo ◽  
Xu Dong Li ◽  
Jing Jing Zhang ◽  
Jun Li Zhao
Keyword(s):  
Friction Coefficient ◽  
Sheet Metal ◽  
Deep Drawing ◽  
Metal Forming ◽  
Thickness Distribution ◽  
Forming Limit ◽  
Drawing Process ◽  
Analysis Software ◽  
Element Analysis ◽  
Wall Thickness Distribution

The box body drawing process is prone to breakage defect. Using finite element analysis software Dynaform5.7, the box part in deep drawing process was simulated. The friction coefficient was observed to change between sheet metal and die. Analysis of sheet metal forming limit and wall thickness distribution，therefore came out with the following conclusion：box deep drawing is affected by the lubrication , when the friction coefficient is lower than 0.17, Lubrication can effectively prevent the box shaped parts from cracks. At the same time, the research still is developing a new drawing.

Novel Punch Design for Nonlinear Strain Path Generation and Evaluation Methods

2015 ◽  
Vol 639 ◽  
pp. 317-324 ◽  
Author(s):  
Mathias Liewald ◽  
Klaus Drotleff
Keyword(s):  
Sheet Metal ◽  
Sheet Metal Forming ◽  
Deep Drawing ◽  
Metal Forming ◽  
Forming Limit ◽  
Material Failure ◽  
Body Parts ◽  
Test Procedures ◽  
Nonlinear Strain ◽  
Strain Paths

The forming limit curve (FLC) is a common method to assess material formability in sheet metal forming processes. It is determined with the Nakajima or Marciniak test according to ISO 12004-2 [1]. The disadvantage of these test procedures is that the results are only valid for linear strain paths. In most real sheet metal forming processes, like deep-drawing of complex car body parts or multi-step processes, nonlinear strain paths exist. It is well-known that the classic FLC cannot describe material failure for nonlinear strain paths.At the Institute for Metal Forming Technology (IFU), new punch geometries have been developed to realise specific nonlinear strain paths in a standard Nakajima testing environment. The formability of sheet materials under nonlinear loading can be determined more accurately when using these new punch geometries than with the classic Nakajima test setup. Different strain paths can be realised depending on the specimen and the punch design, in order to evaluate the formability of the material according to strain conditions as they occur in real forming processes.Within this paper, the results of different punch geometries have been tested using the mild deep-drawing steel DC04. The strain conditions before crack initiation are compared to the standard FLC and to the newly developed IFU-FLC criterion, which can predict material failure under nonlinear strain paths.

Magnesium Sheet Metal Forming Considering its Specific Yield Behavior

2005 ◽  
Vol 6-8 ◽  
pp. 771-778 ◽  
Author(s):  
M. Redecker ◽  
Karl Roll ◽  
S. Häussinger
Keyword(s):  
Sheet Metal ◽  
Elevated Temperatures ◽  
Flow Behavior ◽  
Specific Yield ◽  
Forming Limit ◽  
Forming Process ◽  
Local Flow ◽  
Yield Behavior ◽  
Magnesium Sheet ◽  
Testing Procedures

In recent years very strong efforts have been undertaken to build light weight structures of car bodies in the automotive industry. Structural technologies like Space Frame, tailored blanks and relief-embossed panels are well-known and already in use. Beside that there is a large assortment of design materials with low density or high strength. Magnesium alloys are lighter by approximately 34 percent than aluminum alloys and are considered to be the lightest metallic design material. However forming processes of magnesium sheet metal are difficult due to its complex plasticity behavior. Strain rate sensitivity, asymmetric and softening yield behavior of magnesium are leading to a complex description of the forming process. Asymmetric yield behavior means different yield stress depending on tensile or compressive loading. It is well-known that elevated temperatures around 200°C improve the local flow behavior of magnesium. Experiments show that in this way the forming limit curves can be considerably increased. So far the simulation of the forming process including temperature, strain rates and plastic asymmetry is not state-of-the-art. Moreover, neither reliable material data nor standardized testing procedures are available. According to the great attractiveness of magnesium sheet metal parts there is a serious need for a reliable modeling of the virtual process chain including the specification of required mechanical properties. An existing series geometry which already can be made of magnesium at elevated temperatures is calculated using the finite element method. The results clarify the failings of standard calculation methods and show potentials of its improvement.

Multi-Step Forward Finite Element Method for the Numerical Simulation of Sheet Metal Forming

2011 ◽  
Vol 474-476 ◽  
pp. 251-254
Author(s):  
Jian Jun Wu ◽  
Wei Liu ◽  
Yu Jing Zhao
Keyword(s):  
Numerical Simulation ◽  
Finite Element Method ◽  
Finite Element ◽  
Sheet Metal ◽  
Sheet Metal Forming ◽  
Deep Drawing ◽  
Metal Forming ◽  
Mapping Method ◽  
Constitutive Relationship ◽  
Element Method

The multi-step forward finite element method is presented for the numerical simulation of multi-step sheet metal forming. The traditional constitutive relationship is modified according to the multi-step forming processes, and double spreading plane based mapping method is used to obtain the initial solutions of the intermediate configurations. To verify the multi-step forward FEM, the two-step simulation of a stepped box deep-drawing part is carried out as it is in the experiment. The comparison with the results of the incremental FEM and test shows that the multi-step forward FEM is efficient for the numerical simulation of multi-step sheet metal forming processes.

Thinning and spring back prediction of sheet metal in the deep drawing process

2014 ◽  
Vol 53 ◽  
pp. 797-808 ◽  
Author(s):  
H. Zein ◽  
M. El Sherbiny ◽  
M. Abd-Rabou ◽  
M. El shazly
Keyword(s):  
Sheet Metal ◽  
Deep Drawing ◽  
Drawing Process ◽  
Spring Back ◽  
Deep Drawing Process
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