Sheet Metal Forming Using Polymer Composite Rapid Prototype Tooling

2003 ◽  
Vol 125 (3) ◽  
pp. 247-255 ◽  
Author(s):  
Y. Park ◽  
J. S. Colton
Keyword(s):  
Sheet Metal ◽  
Polymer Composite ◽  
Tool Life ◽  
Sheet Metal Forming ◽  
Metal Forming ◽  
Low Cost ◽  
Rapid Prototype ◽  
Element Model ◽  
Bending Process ◽  
Composite Tooling

To meet the growing demand for rapid, low-cost die fabrication technology in the sheet metal forming industry, easy-to-machine, polyurethane-based, composite board stock is widely used as a rapid tooling material. However, the failure mechanisms of the rapid prototyped tools are not clearly understood, thus making the prediction of tool life difficult. As a fundamental step for effective tool life estimation, the microstructure and the mechanical properties of the polymer composite tooling material were characterized. A finite element model of 90° V-die bending process was developed, and the effects of process parameters on stress distribution in punch and die were investigated through simulation. The simulation results were verified through experiments using instrumented, laboratory-scale punch and die sets.

Die Life Prediction in Rapid Prototype Dies

2002 ◽  
Author(s):  
Young-Bin Park ◽  
Jonathan S. Colton
Keyword(s):  
Sheet Metal ◽  
Sheet Metal Forming ◽  
Metal Forming ◽  
Low Cost ◽  
Rapid Prototype ◽  
Element Model ◽  
Fatigue Properties ◽  
Fabrication Technology ◽  
Die Life ◽  
Bending Process

To meet the growing demand for rapid, low-cost die fabrication technology in the sheet metal forming industry, easy-to-machine, polyurethane-based, composite board stock is used widely as a rapid tooling material. In practice, it is desirable to terminate die life by wear rather than by catastrophic fatigue. However, the failure mechanisms of the rapid prototyped tools are not clearly understood, thus making the prediction of tool life difficult. This paper presents a method to estimate the fatigue life of a sheet metal forming die fabricated from ATH (aluminum trihydrate)-filled polyurethane. A finite element model of 90° V-die bending process was developed, and the effects of process parameters on stress distribution in the punch and die were investigated through simulation. Mechanical testing was performed to characterize the fatigue properties of the tooling material. The computer-simulated results were verified through experiments using instrumented, laboratory-scale punch and die sets.

A Two-Pronged Approach for the Assessment of Springback Variability for Sheet Metal Forming Applications

2013 ◽  
Vol 554-557 ◽  
pp. 957-965 ◽  
Author(s):  
Jérémy Lebon ◽  
Guénhaël Le Quilliec ◽  
Rajan Filomeno Coelho ◽  
Piotr Breitkopf ◽  
Pierre Villon
Keyword(s):  
Sheet Metal ◽  
Sheet Metal Forming ◽  
Metal Forming ◽  
Numerical Models ◽  
Low Cost ◽  
Forming Process ◽  
Metal Forming Process ◽  
Small Random Perturbations ◽  
Complex Phenomena ◽  
Bending Under Tension

Springback assessment for sheet metal forming processes is a challenging issue which requires to take into account complex phenomena (physical non linearities and uncertainties). We highlight that the stochastic analysis of metal forming process requires both a high precision and low cost numerical models and propose a two-pronged methodology to address these challenges. The deep drawing simulation process is performed using an original low cost semi-analytical approach based on a bending under tension model with a good accuracy for small random perturbations of the physical and process parameters. The springback variability analysis is performed using an efficient stochastic metamodel, namely a sparse version of the polynomial chaos expansion.

Effect of Material Parameters Wave on Sheet Metal Springback Using Orthogonal Design Simulation

2011 ◽  
Vol 314-316 ◽  
pp. 585-588 ◽  
Author(s):  
Lei Chen
Keyword(s):  
Sheet Metal ◽  
Sheet Metal Forming ◽  
Metal Forming ◽  
Orthogonal Design ◽  
Direct Analysis ◽  
Element Model ◽  
Internal Stresses ◽  
Common Phenomenon ◽  
Material Parameters ◽  
Simulation Results

Springback is a common phenomenon in sheet metal forming, caused by the elastic redistribution of the internal stresses during unloading. The aim of this search is to investigate the wave of material parameters on the results of forming and springback of sheet metal. A finite element model of cylinder bending benchmark of NUMISHEET’2002 was proposed firstly to simulate bending and springback with contact evolution between tools and blank based on static implicit method. The simulation results agree well with the experiment. Then the effects of the wave of material parameters on forming and springback results are investigated using orthogonal design simulation. Eight factors are investigated with the orthogonal label. The results show the factors have different effects on both the forming and springback. And the significance of the factors is shown through direct analysis of the results.

A Comparison of Rapid Fabrication Methods for Sheet Metal Forming Dies

1999 ◽  
Vol 121 (2) ◽  
pp. 214-224 ◽  
Author(s):  
D. F. Walczyk ◽  
D. E. Hardt
Keyword(s):  
Sheet Metal ◽  
Sheet Metal Forming ◽  
Metal Forming ◽  
Lead Time ◽  
Low Cost ◽  
Cnc Machining ◽  
Die Geometry ◽  
Manufacturing Operations ◽  
Time Shape ◽  
Rapid Fabrication

The need for rapid, low-cost die fabrication and modification methods is greater than ever in the sheet metal forming sector of industry. Consequently, three fabrication methods, suitable for rapid die development schemes, are being compared experimentally based on cost, lead-time, shape resolution and flexibility issues. The candidate methods include CNC-machining a solid billet of material (standard method), assembling and clamping an array of profiled-edge laminations (PEL), and configuring and clamping a matrix of closely-packed pins (discrete die). A matched-set of forming dies was made using each of the candidate fabrication methods for stamping an FEA-verified benchmark part out of steel sheet. Based on the stamping experiments, a PEL die is shown to be similar to CNC-machined dies except that most tooling accessibility problems are eliminated, die geometry limitations are reduced and faster fabrication is possible for harder tool materials. When compared with CNC-machined dies, the discrete die method limits part shape fidelity, maximum forming loads, die geometry and blankholder incorporation. However, the discrete die method excels over the other two methods in terms of lower cost and faster fabrication time. The results of this study make a strong case for the sheet metal forming sector of industry to actively implement the PEL and discrete die methods in their manufacturing operations.

Failure Analysis of Rapid Prototyped Tooling in Sheet Metal Forming—V-Die Bending

2005 ◽  
Vol 127 (1) ◽  
pp. 116-125 ◽  
Author(s):  
Y. Park ◽  
J. S. Colton
Keyword(s):  
Sheet Metal ◽  
Sheet Metal Forming ◽  
Metal Forming ◽  
Low Cost ◽  
Failure Criteria ◽  
Die Life ◽  
Short Run ◽  
Dominant Process ◽  
Die Material ◽  
Tooling Technology

The demand for rapid, low-cost die fabrication and modification technology is greater than ever in the sheet metal forming industry. One category of rapid tooling technology involves the use of advanced polymers and composite materials to fabricate metal forming dies. However, due to their lack of strength as compared to conventional metal dies, the use of polymer dies is often limited to prototype or short-run production. In addition, because the mechanisms by which they fail are not fully understood, the dies are designed on the basis of experience and intuition. This study investigates the failure of V-bending dies fabricated from an easy-to-machine, polyurethane-based, composite board stock. Based on the mechanical behavior of the die material, several failure criteria are proposed to predict die failure mode and the corresponding die life. Both computational and experimental methods are employed to assess the accuracy of the criteria and to identify the dominant process parameters in V-die bending.

A new approach for inverse analysis of springback in a sheet-bending process

2008 ◽  
Vol 222 (11) ◽  
pp. 1363-1374 ◽  
Author(s):  
A Behrouzi ◽  
B M Dariani ◽  
M Shakeri
Keyword(s):  
Finite Element ◽  
Sheet Metal ◽  
Sheet Metal Forming ◽  
Metal Forming ◽  
Three Dimensional ◽  
Die Design ◽  
Element Analysis ◽  
New Approach ◽  
Bending Process ◽  
Process Convergence

In sheet metal-forming processes, the final product can deviate from the target shape as a result of springback. Several approaches have been proposed for analysis of springback and compensating for its error. In this paper, a new approach for springback analysis is presented based on inverse modelling. The springback occurs at the last step of the process and the final geometry of the workpiece can be obtained at the end of direct process modelling. By applying inverse springback analysis, iterative die design becomes possible from the end of the process. Applying bending theory in an inverse algorithm, compensation of springback error is performed in the V-bending process. Convergence of the inverse approach is compared with the direct approach. The inverse springback analysis is developed for three-dimensional analysis of sheet metal forming by applying the explicit—implicit finite element method. Inverse springback modelling of asymmetric and large springback processes is feasible by this new algorithm. The capability and accuracy of this method are investigated for various symmetric and asymmetric processes by comparing results of the method by three-dimensional finite element analysis and V-bending experimental results.

Effect of Tool Modeling Accuracy on Sheet Metal Forming Simulation

2007 ◽  
Vol 340-341 ◽  
pp. 743-748 ◽  
Author(s):  
Takayuki Hama ◽  
Masato Takamura ◽  
Cristian Teodosiu ◽  
Akitake Makinouchi ◽  
Hirohiko Takuda
Keyword(s):  
Sheet Metal ◽  
Sheet Metal Forming ◽  
Metal Forming ◽  
Normal Vector ◽  
Forming Simulation ◽  
Efficient Simulation ◽  
Bending Process ◽  
Modeling Accuracy ◽  
Forming Simulations ◽  
Draw Bending

This paper describes the effect of tool modeling accuracy on the accuracy of springback simulation in sheet metal forming. Simulations of a two-dimensional draw-bending process are carried out by using the polyhedral tool model and the model whose surface is smoothed by quadratic parametric surfaces proposed by Nagata [1]. It is found that the tool modeling, especially the normal vector accuracy in the present model, plays an important role in the prediction not only of deformation but also of stress distribution. The simulated results show that the tool model based on the so-called Nagata patch enables a more accurate and efficient simulation.

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