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.

Rapid Tooling for Sheet Metal Forming Using Profiled Edge Laminations—Design Principles and Demonstration

1998 ◽  
Vol 120 (4) ◽  
pp. 746-754 ◽  
Author(s):  
D. F. Walczyk ◽  
D. E. Hardt
Keyword(s):  
Sheet Metal ◽  
Sheet Metal Forming ◽  
Metal Forming ◽  
General Procedure ◽  
Formal Analysis ◽  
Design Principles ◽  
Rapid Tooling ◽  
Cnc Machining ◽  
Die Geometry ◽  
Die Materials

Sheet metal forming dies constructed of laminations offer advantages over more conventional tooling fabrication methods (e.g. CNC-machining) in terms of tooling accessibility, reduced limitations on die geometry and faster fabrication with harder die materials. Furthermore, the recently introduced Profiled Edge Lamination (PEL) tooling method improves upon other lamination-based tooling methods. Adoption of this promising rapid tooling method by industry is being hindered by the lack of formal analysis, design principles, and manufacturing requirements needed to construct dies in such a manner. Therefore, the propensity for delamination of the die is discussed and preventive measures are suggested. The basic machining instructions, i.e., an array of points and directional vectors for each lamination, are outlined for both compound and planar profiled-edge bevels. Laser, AWJ and flute-edge endmilling are experimentally identified as the most promising methods for machining bevels. Development of a stand-alone PEL fabrication machine is suggested over retrofitting commercially-available 5-axis machines. Finally, the general procedure for creating PEL dies is implemented in the construction of a matched set of sheet metal forming tools. These tools are used to successfully stamp a sheet metal part out of draw-quality steel.

Experimental investigation into a new hybrid-forming process: Incremental stretch drawing

2016 ◽  
Vol 232 (3) ◽  
pp. 475-486 ◽  
Author(s):  
Puneet Tandon ◽  
Om Namah Sharma
Keyword(s):  
Experimental Investigation ◽  
Sheet Metal ◽  
Sheet Metal Forming ◽  
Metal Forming ◽  
Lead Time ◽  
Drawing Process ◽  
Forming Process ◽  
Setup Cost ◽  
Deep Drawing Process ◽  
Incremental Sheet Metal Forming

Incremental sheet metal forming is an evolving process, which is suitable for the production of limited quantities of sheet metal components. The main advantages of this process over conventional forming processes are reduced setup cost and manufacturing lead time, as it eliminates the need of special purpose dies, improves formability, reduces forming forces, and provides process flexibility. The objective of this work is to investigate a new hybrid-forming process, which intends to combine incremental sheet metal forming with deep drawing process and has been named as “incremental stretch drawing.” A number of setups and fixtures were developed to carry out experiments to achieve incremental stretch drawing and understand the mechanism of the process. This process addresses some of the challenges of incremental sheet metal forming, that is, limited formability in terms of forming depth, especially at steeper wall angles and subsequent thinning of sheet. It is observed that the proposed process is able to reduce thinning as much as about 300%, considering same forming depth for incremental sheet metal forming and incremental stretch drawing processes. Improvement in formability, in terms of forming depths, also has been observed to be near about 100% in particular cases.

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.

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.

Large-Scale Laminated Dies for Sheet Metal Forming

2002 ◽  
Author(s):  
Daniel Walczyk
Keyword(s):  
Sheet Metal ◽  
Sheet Metal Forming ◽  
Metal Forming ◽  
Large Scale ◽  
Thick Layer ◽  
Steel Part ◽  
Cnc Machining ◽  
Front End ◽  
Time Required ◽  
Awj Cutting

As part of a 5-year NSF-sponsored project, a design and fabrication system is being developed for Profiled Edge Laminated (PEL) tooling. The PEL tooling method is a thick-layer Rapid Tooling (RT) approach that offers distinct advantages over both conventional CNC machining of billets and other RT processes. Furthermore, the method is ideally suited for developing large-scale sheet metal forming tools. To date, the following design, fabrication and analysis tools have been completed: details of the ‘front-end’ design and analysis process; valid structural and thermal FEL modeling methods for PEL tooling; and development of the ‘back-end’ PEL tool fabrication process consisting of a CAM software system to allow AWJ cutting of individual PELs based on a CAD model. The front end process has been demonstrated with matched die forming of a 2-dimensional steel part. The back-end process has also been demonstrated using a 3-dimensional hydroformed aluminum part. Future work will include incorporation of variable thickness and orientation algorithms that account for stock lamination thicknesses and part dimensional tolerances, more advanced structural and thermal models, the means to predict the cost and time required for fabrication of PEL tools, an investigation of different lamination bonding methods, and additional industrial case studies.

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.

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