An image-driven uncertainty inverse method for sheet metal forming problems

2021 ◽  
pp. 1-52
Author(s):  
Yu Li ◽  
Hu Wang ◽  
Biyu Li ◽  
Jiaquan Wang ◽  
Enying Li
Keyword(s):  
Sheet Metal ◽  
Sheet Metal Forming ◽  
Metal Forming ◽  
Material Flow ◽  
Inverse Method ◽  
Approximate Bayesian Computation ◽  
Design Parameters ◽  
Sufficient Statistics ◽  
Margin Of Safety ◽  
Approximate Bayesian

Abstract The purpose of this study is to obtain a margin of safety for material and process parameters in sheet metal forming. Commonly applied forming criteria are difficult to comprehensively evaluate the forming quality directly. Therefore, an image-driven criterion is suggested for uncertainty parameter identification of sheet metal forming. In this way, more useful characteristics, material flow, and distributions of safe and crack regions, can be considered. Moreover, to improve the efficiency for obtaining sufficient statistics of Approximate Bayesian Computation (ABC), a manifold learning-assisted ABC uncertainty inverse framework is proposed. Based on the framework, the design parameters of two sheet metal forming problems, an air conditioning cover and an engine inner hood, are identified.

Multi-Input Multi-Output (MIMO) Modeling and Control for Stamping

2010 ◽  
Vol 132 (4) ◽  
Author(s):  
Yongseob Lim ◽  
Ravinder Venugopal ◽  
A. Galip Ulsoy
Keyword(s):  
Sheet Metal ◽  
Sheet Metal Forming ◽  
Metal Forming ◽  
Material Flow ◽  
Process Model ◽  
Complex Geometry ◽  
Flow Characteristics ◽  
Forming Process ◽  
Punch Force ◽  
Force System

The binder force in sheet metal forming controls the material flow into the die cavity. Maintaining precise material flow characteristics is crucial for producing a high-quality stamped part. Process control can be used to adjust the binder force based on tracking of a reference punch force trajectory to improve part quality and consistency. The purpose of this paper is to present a systematic approach to the design and implementation of a suitable multi-input multi-output (MIMO) process controller. An appropriate process model structure for the purpose of controller design for the sheet metal forming process is presented and the parameter estimation for this model is accomplished using system identification methods. This paper is based on original experiments performed with a new variable blank holder force (or variable binder force) system that includes 12 hydraulic actuators to control the binder force. Experimental results from a complex-geometry part show that the MIMO process controller designed through simulation is effective.

Numerical Investigation of Dry and Lubricated Sheet Metal Forming Processes

2015 ◽  
Vol 651-653 ◽  
pp. 1029-1035 ◽  
Author(s):  
Marion Merklein ◽  
Emanuela Affronti ◽  
Jennifer Steiner
Keyword(s):  
Sheet Metal ◽  
Sheet Metal Forming ◽  
Metal Forming ◽  
Material Flow ◽  
Test Procedure ◽  
Discrete Control ◽  
Experimental Investigations ◽  
Finite Element Software ◽  
Dry Forming ◽  
Sustainable Usage

The current global development towards efficient and sustainable usage of resources as well as a stronger environmental awareness motivates lubrication abandonment in metal forming. Dry forming processes accomplish besides a green production technology also a shortage in production steps and time. However, the change of the tribological conditions influences the material flow during the forming operations and has therefore to be taken into account for the design of complex sheet metal forming operations. The aim of this study is a comparison of dry and lubricated processes by numerical as well as experimental investigations. To ensure reliable results a test setup is necessary which provides a discrete control of the process parameters. Furthermore, an analysis of the local material flow by an optical strain measurement system during the whole test procedure should be possible. These requirements are well fulfilled by the so called Nakajima test, which is typically used for the characterisation of the formability of sheet metals. The influence of varying friction coefficients on the material behaviour is discussed based on the numerical model built up in the Finite Element Software LS-Dyna. The numerical results show a good conformity with the experimental outcomes by identifying the strain localisation. Based on the gained knowledge of the investigations an increase of process understanding for dry forming operations will be derived.

Active Material Flow Control during High-Pressure Sheet Metal Forming

2005 ◽  
Vol 6-8 ◽  
pp. 377-384 ◽  
Author(s):  
Peter Groche ◽  
C. Metz
Keyword(s):  
Sheet Metal ◽  
Sheet Metal Forming ◽  
Metal Forming ◽  
Material Flow ◽  
High Pressures ◽  
Active Material ◽  
Sheet Thickness ◽  
Blank Holder ◽  
Rotationally Symmetric ◽  
Material Flow Control

During forming of non-rotationally symmetric sheet metal parts at high pressures nonuniform deformation conditions arise in the flange area. These deformations vary in height and consequently lead to heterogeneous sheet thickness distributions. When using semi-rigid tools, high clamping forces are necessary in order to compensate for the developing sheet thickness variations in the flange area and to avoid leakages of the system or wrinkling. Moreover, the heterogeneous distribution of the clamping force is strengthened by press inaccuracies. This results in a higher surface pressure distribution on one side of the flange and finally in a non-uniform material flow out of the flange area. The development of a segmented active-elastic blank holder enables an active material flow control of the flange movement during sheet metal forming at high pressures. The local elasticity of the active-elastic blank holder is based on an optimized layout of the local tool rigidity. For this purpose, different grooves were integrated below the blank holder surface. This paper provides an overview of the developed technology, advantages with regard to the part’s quality, and recent results comparing the production of non-rotationally symmetric parts with segmented active-elastic tools vs. semi-rigid tools.

Evaluation of parameters for application of Laser Surface Texturing (LST) in tooling for the sheet-metal forming process

2018 ◽  
Vol 70 (4) ◽  
pp. 620-627 ◽  
Author(s):  
José Jaime Taha-Tijerina ◽  
GerardoTadeo Garza ◽  
Demófilo Maldonado-Cortés
Keyword(s):  
Sheet Metal ◽  
Sheet Metal Forming ◽  
Metal Forming ◽  
Surface Texturing ◽  
Laser Surface ◽  
Laser Surface Texturing ◽  
Critical Parameters ◽  
Design Parameters ◽  
Content Type ◽  
Positive Effects

Purpose The purpose of this paper is to evaluate the effects of microcavities, diameter and depth, in tribological performance, of the application of laser surface texturing (LST) and LST gradient (LSTG) techniques, to understand and define the critical parameters of these techniques in sheet-metal forming tools. Design/methodology/approach The paper studies the effect of studied critical parameters of LST and LSTG techniques, on block-on-ring configuration for tribology evaluation. Experimental design parameters for LST and LSTG are proposed and evaluated for the best tribology performance (COF and wear). Findings The results show that the application of optimized LST process could represent a 42 per cent improvement on the COF and up to 86 per cent enhancement in the COF results for the LSTG application. Practical implications The results show that LST and LSTG techniques present significant positive effects on the tribological properties of sheet-metal forming materials. Originality/value This demonstrates the potential of LST technique applied to industrial tooling, and the LSTG pattern which further increases the benefits obtained with the LST technique, particularly in which friction and wear areas are critical. A response surface map is developed to determine the control parameters which are useful for the tooling design. These techniques could be used for metal-forming applications like deep-drawing, achieving an increased tool life.

A Rapid Inverse Method of Material Performance Parameters in Sheet Metal Forming

2012 ◽  
Vol 538-541 ◽  
pp. 1035-1040
Author(s):  
Hua Liu ◽  
Kai Yong Jiang ◽  
Bin Liu ◽  
Ping Lu
Keyword(s):  
Genetic Algorithm ◽  
Sheet Metal ◽  
Sheet Metal Forming ◽  
Metal Forming ◽  
Inverse Method ◽  
Orthogonal Experiment ◽  
The Self ◽  
Performance Parameters ◽  
Sensitive Material ◽  
Material Parameters

This paper proposes a fast and convenient method to inverse the material performance parameters in stamping forming. This method effectively combined with the FEM and the genetic algorithm. The reverse objective function was constructed with the thickness which is easily measured from the stamped parts, and then a genetic algorithm was programmed; The thickness-sensitive material performance parameters can be acquired through the orthogonal experiment, then these material parameters can be inversed by the self-programming genetic algorithm. Finally, a stamping case proves this method is precise, rapid and valid.

Material Flow Control in High Pressure Sheet Metal Forming of Large Area Parts with Complex Geometry Details

2005 ◽  
Vol 76 (12) ◽  
pp. 905-910 ◽  
Author(s):  
Michael Trompeter ◽  
Erkan Önder ◽  
Werner Homberg ◽  
Erman Tekkaya ◽  
Matthias Kleiner
Keyword(s):  
High Pressure ◽  
Flow Control ◽  
Sheet Metal ◽  
Sheet Metal Forming ◽  
Metal Forming ◽  
Material Flow ◽  
Complex Geometry ◽  
Large Area ◽  
Material Flow Control
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