Applying 2k Factorial Design to Study on Parameters Affecting Springback of Forming of Advanced High Strength Steel Sheets (AHSS)

2017 ◽  
Vol 872 ◽  
pp. 83-88
Author(s):  
Ramil Kesvarakul ◽  
Chamaporn Chianrabutra ◽  
Watcharapong Sirigool
Keyword(s):  
Elastic Recovery ◽  
Weight Ratio ◽  
High Strength ◽  
Die Design ◽  
Statistical Experimental Design ◽  
Blank Holder Force ◽  
Forming Process ◽  
Blank Holder ◽  
Punch Radius ◽  
Springback Angle

Advanced high strength steels (AHSS) are widely used in the automotive industry due to their appropriate strength to weight ratio. This alloy has unique hardening behavior and variable unloading elastic modulus; however, the unavoidable obstacle of AHSS sheet metal forming is springback. The springback is a result of elastic recovery and residual stress. The aim of this study is to determine the proper process parameters enabling the reduction of the springback defects in AHSS forming process. This work was divided into two parts, regarding to the effects of numerical parameters and process parameter on forming AHSS. In this paper, a U-shape forming was used to examine the springback behaviors, such as springback angle, sidewall curl, and thickness, through an experiment. To achieve this purpose, 2k factorial statistical experimental design has been employed to investigate the parameters affecting the springback of forming in AHSS to find out the main effect in the springback reduction focusing on using as a guideline for die design. It showed that the blank holder force is the most influential parameter. The second is the punch radius. However, the blank holder force and punch radius is not simple to adjust in die design, the die radius becomes the important parameter to be used to reduce the springback angle.

The Influence of the Blank Holder Force during Forming Process of a U-Shaped Part Made from AZ31 Magnesium Alloy

2015 ◽  
Vol 809-810 ◽  
pp. 265-270
Author(s):  
Aurelian Albut ◽  
Valentin Zichil ◽  
Adrian Judele
Keyword(s):  
Magnesium Alloy ◽  
Sheet Metal ◽  
Elastic Recovery ◽  
Rolling Direction ◽  
Sheet Thickness ◽  
Bending Moment ◽  
Blank Holder Force ◽  
Forming Process ◽  
Blank Holder ◽  
Shaped Part

In case of sheet metal forming the main dimensional errors are caused by the springback phenomena. The present work deals with numerical simulation related to draw bending and springback of U - shaped part made from magnesium alloy. The current paper is trying to prove out the important role of the blank holder force with respect to the forming process. Though novel approaches relating to the formality of magnesium alloy sheets, the change of springback due to the characteristic of each process should be verified by finite element method. Springback refers to the elastic recovery of deformed parts. Springback occurs because of the elastic relief from the bending moment imparted to the sheet metal during forming. Springback is mainly influenced by the sheet thickness, the punch and die profile radii, initial clearance between punch and die, friction conditions, rolling direction of the materials, blankholder force and by material properties. In this study, the magnesium alloy strips with two types of material having the thickness of 1mm, are used to investigate springback characteristics in U-shape bending. The Dynaform 5.6 software was used to simulate the forming process, in which the blank holder force takes values between 15 and 35 kN. In this study, the springback was analyzed by U-forming at room temperature conditions with different blank holder forces. Springback decreased with the increase of the blank holding force. Excessive holding force cause irregular thinning of the material, especially in the radius area.

scholarly journals Study on forming process and spring back control of high strength sheet based on Dynaform

2018 ◽  
Vol 232 ◽  
pp. 02039
Author(s):  
cunping Liu
Keyword(s):  
Velocity Profile ◽  
High Strength Steel ◽  
High Strength ◽  
Steel Part ◽  
Drawing Process ◽  
Spring Back ◽  
Blank Holder Force ◽  
Forming Process ◽  
Blank Holder ◽  
Motion Mode

The drawing process of a high strength steel part without blank holder force was numerically simulated based on Dynaform. In present investigation, the drawing velocity and velocity profile motion of punch was studied by simulating the drawing operation of high strength steel part. The results show that restricting drawing velocity and controlling velocity profile motion of punch could all reduce the spring back. The measure of restricting drawing velocity could reduce non-pressure forming spring back about 31% and Trapezoidal motion mode of punch is the most beneficial to reduce spring back.

Springback Experimental Research of Advanced High-Strength Steel

2013 ◽  
Vol 842 ◽  
pp. 284-288
Author(s):  
Jun Yi Ke ◽  
Yu Qi Liu ◽  
Gui Li ◽  
Ting Du
Keyword(s):  
Yield Stress ◽  
Experimental Research ◽  
High Strength Steel ◽  
High Strength ◽  
Holding Time ◽  
Impact Factors ◽  
Advanced High Strength Steel ◽  
Blank Holder Force ◽  
Blank Holder ◽  
Springback Angle

Springback is one of the major problems of high strength steel.Based on the NUMISHEET’96 S_Rail standard examination questions,using the characteristics of the servo press 200T,the blank holder force,different pressure holding time and the holding times of advanced high strength steel DP280-440, DP340-590, DP400-780 are studied. By changing one of the three impact factors ,three group experiments are carried out.The experimental results show that the springback can change evidently with the increasing of the blank holder force and the holding times,but the holding time has little influence on the springback.What’s more,the springback angle of DP400-780 is the biggest ,proving the higher the yield stress,the bigger the springback angle.Therefore, in the stamping of advanced high strength steel, increasing the blank holder force and holding times are effective methods to solve the springback.

Finite Element Simulation of Deep Drawing Processes for Shell Bar RR Impact RH/LH

2018 ◽  
Vol 875 ◽  
pp. 24-29
Author(s):  
Aekkapon Sunanta ◽  
Surasak Suranuntchai
Keyword(s):  
Finite Element ◽  
Deep Drawing ◽  
Yield Function ◽  
Production Quality ◽  
Die Design ◽  
Blank Holder Force ◽  
Forming Process ◽  
Blank Holder ◽  
Restraining Force ◽  
Shell Bar

Finite Element Method (FEM) is one of the most useful techniques to analyze problems in metal forming process because of this technique can reduce cost and time in die design and trial step [1]. This research is aimed to predict the optimal parameters in order to eliminate cracks and wrinkles on automotive deep drawing product “Shell Bar RR Impact RH/LH”. The material was made from high strength steel JSC440W sheet with thickness 1.8 mm. The parameters that had been investigated were blank holder force (BHF) and drawbead restraining force (DBRF). 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 material properties assumed to be anisotropic, behaved according to the constitutive equation of power law and deformed elastic-viscoplastic, which followed Barlat 3 components yield function. Most of the defects such as cracks and wrinkles were found during the processes on the parts. In the past, the practical productions were performed by trial and error, which involved high production cost, long lead time and wasted materials. From the results, when decreased blank holder force to 30 tons, cracks on the part were removed but wrinkles had a tendency to increase in part area because of this part is the asymmetrical shape. Finally, applying about drawbead restraining force at 154.49 and 99.75 N/mm could improve product quality. In conclusion, by using the simulation technique, the production quality and performance had been improved.

The Analysis on the Stamping Formability of High Strength Steel

2021 ◽  
Vol 885 ◽  
pp. 3-9
Author(s):  
Wen Yu Ma ◽  
Jian Wei Yang ◽  
Ye Yao ◽  
Yong Qiang Zhang ◽  
Jun Zhang
Keyword(s):  
High Strength Steel ◽  
High Strength ◽  
Blank Holder Force ◽  
Blank Holder ◽  
Variable Blank Holder Force ◽  
Automotive Part ◽  
Blank Shape ◽  
Shaped Blank

Recently the high strength steel has been applied in the automotive more and more widely. In this study, the effect of blank shape on the formability of an automotive part was analyzed. The three kinds of blank shapes were chosen, including a rectangular shaped blank, a blank with two corners cut straightly and a blank with two corners cut in curve. The effect of the variable blank holder force on the formability was studied. The four kinds of variable blank holder force were applied. The blank shape in this part is the blank with two corners cut curve. The results show that the blank with two corners curve is the most suitable. And the blank holder force from 1000 kN to 1500 kN is the most useful for the formability.

The Impact Analysis of Stamping Process Factors Based on Dynaform

2013 ◽  
Vol 712-715 ◽  
pp. 642-646
Author(s):  
Zhen Gang He ◽  
Yan Ping Zheng ◽  
Gai Yan
Keyword(s):  
Quality Evaluation ◽  
Impact Analysis ◽  
Simulation Analysis ◽  
Blank Holder Force ◽  
Forming Process ◽  
Blank Holder ◽  
Stamping Process ◽  
The Coefficient Of Friction ◽  
Process Factors ◽  
The Impact

Combining with practical needs in production, it carried out the numerical simulation analysis of automobile beam stamping forming process based on Dynaform in this paper. According to quality evaluation index of forming parts, it analyzed the effect of variation of blank holder force, the stamping speed, the coefficient of friction and draw bead on stamping quality. It forecast the quality problems happened in forming process, which provides the theoretical basis for design of stamping process and mold.

Springback Analysis in Bilayer Material Bending

2017 ◽  
Author(s):  
Chetan P. Nikhare
Keyword(s):  
Fuel Consumption ◽  
Elastic Recovery ◽  
Dissimilar Materials ◽  
High Strength Steels ◽  
Thick Layer ◽  
High Strength ◽  
Geometric Error ◽  
Forming Process ◽  
Tailor Welded Blanks ◽  
Geometric Defect

Exponential increase in the use of auto vehicles, and thus the fuel consumption, which relates to the air pollution, vehicle industry are in a strict environmental regulation from government. Due to which the innovation related to light-weighting is not only an option anymore but became a mandatory necessity to decrease the fuel consumption. To achieve this target, industry has been looking in fabricating components from high strength to ultra-high strength steels. With the usage of these material the lightweight was achieved by reducing a gage thickness. However due to their high strength property often challenges occurred are higher machine tonnage requirement, sudden fracture, geometric defect, etc. The geometric defect comes from elastic recovery of a material, which is also known as a springback. Springback is commonly known as a manufacturing defect due to the geometric error in the part, which would not be able to fit in the assembly without secondary operation or compensation in the forming process. Due to these many challenges, other research route involved is composite material, where light materials can be used with high strength material to reduce the overall vehicle weight. This generally includes, tailor welded blanks, multi-layer material, mechanical joining of dissimilar material, etc. Due to the substantial use of dissimilar materials, these parts are also called as hybrid components. It was noted that the part weight decreases with the use of hybrid components without compromising the integrity and safety. In this paper, a springback analysis was performed considering bilayer metal. For this two dissimilar materials aluminum and composite was considered as bonded material. This material was then bent in a channel forming set-up. The bilayer springback was compared in different condition like aluminum layer on punch side and then on die side. These results were then compared with the baseline springback of only aluminum thin and thick layer. It was found that the layer, which sees the punch side, matters due to the differences in elastic properties for both material and thus it directly influences the springback.

Effect of Blank Holder Force with Low Frequency Vibration Technique in Circular-Cup Deep-Drawing Using AZ31 Magnesium Alloy Sheet

2011 ◽  
Vol 383-390 ◽  
pp. 2785-2789
Author(s):  
Naoki Horiike ◽  
Shoichiro Yoshihara ◽  
Yoshitaka Tsuji ◽  
Yusuke Okude
Keyword(s):  
Deep Drawing ◽  
Low Frequency ◽  
Lubricating Oil ◽  
Drawing Process ◽  
Blank Holder Force ◽  
Forming Process ◽  
Blank Holder ◽  
Deep Drawing Process ◽  
Low Frequency Vibration ◽  
Friction Performance

In the deep-drawing process, the application of low-frequency vibration to the blank material has recently been focused on with the aim of improving the friction performance between the die and the blank material. A servo-controlled press machine is suitable for applying low-frequency vibration to the blank during the deep-drawing process, because the punch speed and blank holder force (BHF) are easily controlled as process parameters by using the servo motors. In this study, a BHF with low-frequency vibration was proposed as a technique for improving deep-drawability, which is mainly affected by the friction performance and the lubricant condition. We found that the friction performance between the blank surface and the blank holder was decreased in the case of a BHF with low-frequency vibration since the lubricating oil rapidly flowed into the clearance during the forming process. Furthermore, for a BHF with low-frequency vibration, the punch force and the deformation resistance were lower than those in a deep-drawing test without low-frequency vibration.

Effect of Variable Geometry on Springback of High Strength Steel Materials

2015 ◽  
Vol 1134 ◽  
pp. 154-159
Author(s):  
Muhamad Sani Buang ◽  
Shahrul Azam Abdullah ◽  
Juri Saedon ◽  
Yupiter H.P. Manurung ◽  
Mohd Shahir Mohd Hairuni ◽  
...  
Keyword(s):  
Finite Element ◽  
Finite Element Simulation ◽  
High Strength Steel ◽  
High Strength ◽  
Bending Test ◽  
Geometrical Parameters ◽  
Forming Process ◽  
Element Simulation ◽  
Punch Radius ◽  
Prevention Method

Springback is the phenomenon in which the material strip unbends itself after forming process. It is caused by the geometrical, mechanical properties or other process parameters. This paper focused on finite element simulation investigation on effects of geometrical parameters on the springback amount of the High Strength Steel (HSS). Two geometrical parameters, punch radius (Rp) and die opening (Wo) were selected and their effect on springback studied. Finite element simulation of U-bending test was performed using Simufact.formingTM with material database (MatILDa) and the level of the springback was measured. The result of the simulation shows that different values of punch radius (Rp) and die opening (Wo) are significant to the springback effect. 3 variable values of (Rp) and (Wo) selected in this studied are (2mm, 4mm, 6mm) and (30mm, 36mm, 48mm) respectively. The findings of the simulation could be used to accurately and reliably predict springback behavior of the tested material. The value of the springback increases, as the value of the die opening (Wo) increases. Meanwhile, the increasing value of the punch radius (Rp) will lead to decreasing springback value. From this finding, a proper prevention method can be taken to eliminate springback, achieve improvement in the forming process as well as reduce processing time and cost.

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