New Criterion for Prediction of the Wrinkle Formation in Deep Drawing Process

2015 ◽  
Vol 651-653 ◽  
pp. 71-76 ◽  
Author(s):  
Mathias Liewald ◽  
Fei Han ◽  
Ranko Radonjic
Keyword(s):  
Sheet Metal ◽  
Deep Drawing ◽  
Metal Forming ◽  
Failure Modes ◽  
Limit Curve ◽  
Metal Part ◽  
Sheet Metal Parts ◽  
Forming Technology ◽  
Wrinkling Analysis ◽  
New Criterion

Wrinkling is one of the primary failure modes in deep drawing of sheet metal parts. Previous studies showed that the second principle stress can be a measure for the initiation and growth of wrinkles. The wrinkling analysis is usually made with using conical cup geometries. Recent experiments and numerical simulation results at the Institute for Metal Forming Technology (IFU) showed that the wrinkling analysis using simple conical cup geometries is not suitable for description of complex wrinkling conditions for real deep drawing processes. In the presented experimental results, fender shaped geometry was chosen as an example. During deep drawing of this geometry, different wrinkling formulation mechanisms were observed. Regarding these wrinkling mechanisms, a new wrinkling limit curve can be determined. By use of this new wrinkling limit curve, it is possible to detect the occurrence of wrinkles in each area of the formed sheet metal part until the wrinkle is finally formed.

Research on the Forming Path for Fabricating the Sheet-Metal Part with Non-Horizontal End Face Using CNC Incremental Forming

2014 ◽  
Vol 599-601 ◽  
pp. 413-416 ◽  
Author(s):  
Hu Zhu ◽  
Jin Ju ◽  
Yi Bo Liu
Keyword(s):  
Sheet Metal ◽  
Incremental Forming ◽  
Analysis Method ◽  
Metal Part ◽  
Element Analysis ◽  
Sheet Metal Parts ◽  
Cnc Incremental Forming ◽  
Forming Technology ◽  
The Finite Element Analysis

For the purpose of the fabrication of the sheet-metal parts with non-horizontal end face using the sheet metal CNC incremental forming technology, two kinds of path generating methods, namely the level path perpendicular to Z axis method and the equidistant path parallel to sheet metal are proposed in this paper. Both of the paths are generated by Visual C++ and OpenGL graphics library, the effect of the two kinds of forming paths to the forming quality of the sheet part with non-horizontal end face is researched using the finite element analysis method in this paper.

Sheet-Bulk Metal Forming of Preformed Sheet Metal Parts

2011 ◽  
Vol 473 ◽  
pp. 83-90 ◽  
Author(s):  
Thomas Schneider ◽  
Marion Merklein
Keyword(s):  
Sheet Metal ◽  
Deep Drawing ◽  
Metal Forming ◽  
Sheet Plane ◽  
Bulk Metal ◽  
Bulk Metal Forming ◽  
Sheet Metal Parts ◽  
Bulk Forming ◽  
Process Factors ◽  
Functional Components

Due to ecological and economic challenges there is a rising demand on closely-tolerated complex functional components. Regarding short process chains and improved mechanical properties conventional forming processes are often limited. A promising approach to meet these requirements can be seen in the combination of traditional sheet and bulk metal forming processes, to form sheet metals out of the sheet plane with typical bulk forming operations. The challenge of applying conventional bulk forming operations on sheet metal is the interaction between regions of high and low deformation, which is largely unknown in literature. To analyze this topic fundamentally, a process combination of deep drawing and upsetting is developed for manufacturing tooth-like elements at pre-drawn cups. To fully understand material flow out of the sheet plane into the tooth cavity and to identify and qualify process factors depending on the functional elements´ geometry and friction, a single upsetting stage forming a simplified model of the blank is virtually analyzed with finite-element simulation. By inhibiting the forming history of the pre-drawn blank, the upsetting process can be investigated without interactions with a previous deep drawing operation.

scholarly journals Modelling real contact areas caused by material straining effects in sheet metal forming simulation

2021 ◽  
Author(s):  
Peter Essig ◽  
Mathias Liewald ◽  
Maximilian Burkart ◽  
Maxim Beck
Keyword(s):  
Sheet Metal ◽  
Surface Pressure ◽  
Sheet Metal Forming ◽  
Deep Drawing ◽  
Metal Forming ◽  
Sheet Metal Part ◽  
Metal Part ◽  
Forming Simulation ◽  
Contact Areas ◽  
Surface Pressure Distribution

Shortened product development processes in automotive industry combined with the upcoming lack of experts do challenge sheet metal part production fundamentally. Tryout time and manufacturing costs of large forming dies today are significantly influenced by their digitally supported engineering. The forming process by such tools is beside other influences is affected by elastic deformations of forming dies and press structure as well as contact areas between die and sheet metal part. In deep drawing such contact areas are influenced by the blank properties and the flange behavior in terms of thickening and thinning. Recent developments in sheet metal forming simulation do consider advanced friction models and structural modeling of die and press components improving simulation accuracy. Nevertheless thinning or thickening of sheet metal results into localized surface pressure distribution during deep drawing. For this reason, it is not sufficient to use the currently common practice of homogeneous surface pressure distribution in sheet metal forming simulation. In this respect, this paper presents a numerical approach for consideration of straining effects in the sheet metal part during forming operation. For this purpose, a systematic process improvement was developed in this paper to identify contact areas via a numeric simulation parameter. Validating the numerical investigation, a rectangle cup die is used, considering major strain. The main results of this contribution for that reason show how simulated contact areas can be estimated by reverse engineering of real forming parts. Hereby straining based contact areas lead to a novel contact area design in process planning, resulting in efficient die tryout.

Numerical Simulation in Deep Drawing of Cylindrical Cup with Circular Diving Equally Small Holes on Edge of Circle Blank

2010 ◽  
Vol 148-149 ◽  
pp. 769-773
Author(s):  
Yu Qing Shi
Keyword(s):  
Sheet Metal ◽  
Deep Drawing ◽  
Metal Forming ◽  
Failure Modes ◽  
Small Hole ◽  
Drawing Process ◽  
Deep Drawing Process ◽  
Blank Shape ◽  
Cylindrical Cup ◽  
Small Holes

Deep-drawing is one of the most important methods to form sheet metal ,but wrinkling and fracture are the main failure modes in sheet-metal forming. Blank shape is important for deep-drawing because of an effective way to promote deep formability sheet metal .This paper presents an attempt to determine the effect of circle blank with circular diving equally small hole on edge of circle blank on the fracture and wrinkling and was investigated using 08Al sheet metal .The circular blank with small hole of diameter = was analyzed to eliminate wrinkling and fracture in deep-drawing .The aim of this study is to investigate the circular diving equally small hole on edge of circle blank on formability in the deep-drawing process and to obtain useful date from the industrial field .The experiment show that limit formability promote with punching small holes on circle blank in deep-drawing process.

Improving the Quality in Deep Drawing of Rectangle Parts Using Variable Blank Holder Force

2010 ◽  
Vol 37-38 ◽  
pp. 521-524
Author(s):  
Yu Qing Shi
Keyword(s):  
Sheet Metal ◽  
Sheet Metal Forming ◽  
Deep Drawing ◽  
Metal Forming ◽  
Failure Modes ◽  
Blank Holder Force ◽  
Blank Holder ◽  
Variable Blank Holder Force

Wrinkling and tearing are the main failure modes in sheet-metal forming. Wrinkle may occur at the start of a punch stroke if the blank-holder force (BHF) is too low, and tearing may occur at the end of a stroke if the BHF is too high. The BHF is important for deep-drawing because of an effective way to promote deep formability sheet metal. They can be reduced or eliminated by manipulating a suitable BHF during sheet-metal forming. This paper presented an attempt to determine the effect of variable BHF on the tearing and wrinkling and investigated using 08Al sheet metal. The experiment show that tearing and wrinkling can be eliminated and the quality of deep drawing of rectangle parts can be improved using variable BHF.

Numerical Simulation in Deep Drawing of Cylindrical Cup with Elliptical Shape Die Shoulder

2010 ◽  
Vol 148-149 ◽  
pp. 1355-1359
Author(s):  
Yu Qing Shi ◽  
Ai Zhi Guan
Keyword(s):  
Sheet Metal ◽  
Deep Drawing ◽  
Metal Forming ◽  
Failure Modes ◽  
Major Axis ◽  
Minor Axis ◽  
Drawing Process ◽  
Deep Drawing Process ◽  
Elliptical Shape ◽  
Cylindrical Cup

Wrinkling and tearing are the main failure modes in sheet-metal forming. The radius of die is important for deep-drawing because of an effective way to promote deep formability sheet metal .This paper presents an attempt to determine the effect of various elliptical shape die shoulder on the fracture and wrinkling and was investigated using 08Al sheet metal .The ellipse with minor axis of b=4.5mm and major axis of a=6.5mm,a=7mm,a=8mm ,a=10mm were analyzed to eliminate wrinkling and fracture in deep-drawing .The aim of this study is to investigate the effect of elliptical major axis and elliptical minor axis variables in elliptical shape die shoulder on formability in the deep-drawing process and to obtain useful date from the industrial field .The experiment show that limit formability promote with elliptical shape die shoulder in deep-drawing process.

Design of a New Type Flexible Stretch-Forming Machine

2013 ◽  
Vol 690-693 ◽  
pp. 2218-2221 ◽  
Author(s):  
Qi Gang Han ◽  
Ming Zhe Li ◽  
Qiang Zhang ◽  
Ya Dong Chen ◽  
Wen Zhi Fu
Keyword(s):  
Sheet Metal ◽  
Metal Forming ◽  
High Speed ◽  
High Speed Train ◽  
Stretch Forming ◽  
Sheet Metal Parts ◽  
Large Size ◽  
Forming Technology ◽  
Plastic Forming ◽  
New Type

Stretch forming machine (SFM) is most effective plastic forming equipment for large-size, thin and flat-deformation parts, which can decrease the springback phenomenon in sheet metal forming. In order to enhance the performance of SFM, a flexible stretch forming machine (FSFM) was developed by the authors successfully, which is made up of jaw clamping mechanisms, stretching mechanisms, universal push-pull mechanisms, and a carriage. Our experimental results indicated that the rate of materials utilization and close-fitting dies can be increased to 80 %. In addition, FSFM can reduce the complex of control-system and decrease the expense of machine sharply. FSFM have been used for double-curved sheet metal manufacturing successfully, such as the cab of high-speed train. This work has a strong value in enhance the stretch forming technology for double-curved sheet metal parts.

Temperiertes Tiefziehen von Magnesiumfeinblech*/Development of a tempered deep-drawing tool for hot forming of magnesium sheet metal

2018 ◽  
Vol 108 (10) ◽  
pp. 657-661
Author(s):  
M. Liewald ◽  
S. Walzer
Keyword(s):  
Sheet Metal ◽  
Deep Drawing ◽  
Metal Forming ◽  
Development Process ◽  
Lightweight Design ◽  
Tool Development ◽  
Magnesium Sheet ◽  
Forming Technology ◽  
Design Requirements ◽  
The Impact

Die steigende Funktionalität von Bauteilen aus Blechwerkstoffen und die kontinuierlich wachsenden Anforderungen an den Leichtbau im Sinne dünnwandiger, struktursteifer Karosseriebauteile beeinflussen die Konstruktion solcher Blechteile und dazugehöriger Werkzeuge zunehmend. In diesem Zusammenhang wurde am Institut für Umformtechnik ein temperiertes Werkzeugkonzept zum Tiefziehen von Magnesiumfeinblech entwickelt, bei dem sowohl die mechanischen Werkstoffparameter als auch die Prozessparameter in den Werkzeug-Entwicklungsprozess einflossen.   The increasing functionality of sheet metal components as well as the continuously growing lightweight design requirements in terms of thin-walled, structurally rigid vehicle parts steadily influence the design of such sheet metal components and corresponding tools. In this context, the Institute for Metal Forming Technology has developed a temperature-controlled tool concept for deep drawing of magnesium sheet metal, in which both the influencing mechanical material properties and the impact of process parameters were included in the tool development process.

Economical and Ecological Aspects of Single Point Incremental Forming Versus Deep Drawing Technology

2007 ◽  
Vol 344 ◽  
pp. 931-938 ◽  
Author(s):  
Aleš Petek ◽  
Gašper Gantar ◽  
Tomaz Pepelnjak ◽  
Karl Kuzman
Keyword(s):  
Sheet Metal ◽  
Sheet Metal Forming ◽  
Deep Drawing ◽  
Metal Forming ◽  
Incremental Forming ◽  
Single Point ◽  
Single Point Incremental Forming ◽  
Forming Process ◽  
Forming Technology ◽  
Ecological Aspects

In contemporary industrial production the ecological aspects have increasingly important role in selection of sheet metal forming process. To produce sheet metal parts with minimal environmental burdening the shortening of forming processes including the procedures for production of appurtenant forming tools as well as decrease use of lubricant is prerequisite. The ecological aspects have to be considered also already in developmental phase where the forming technology is evaluated in digital environment with FEM simulations. In addition, particularly in small and medium batch production the geometrically complex parts are difficult to form economically with conventional forming processes like deep drawing or stretching. Therefore, new concepts like hydro-mechanical forming or incremental sheet metal forming were developed. In order to select the optimal forming process the production costs as well as the environmental aspects like lubrication, noise, pollution and energy per produced part have to be considered. The paper is focused towards the comparison of conventional deep drawing (DD) process aimed for forming the pyramid-shaped part with single point incremental forming technology (SPIF). The economical and ecological aspects affecting the successful forming by both concepts are determined. Comparative evaluation was established in order to present advantages and drawbacks of each analysed technology.

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.

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