• International Journal of Precision Engineering and Manufacturing
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• v.5 no.1
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• pp.36-41
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• 2004

The blanking of thin sheet metal using progressive dies is an important process on production of precision electronic machine parts such as IC leadframe. This paper summarizes the results of simulating the progressive blanking process by means of LS/DYNA. In order to verify the influence of blanking order on the final lead profile and deformed configuration, simulation technique has been proposed and analyzed using a commercial FEM code, LS/DYNA. The results of FE-simulations are in good agreement with the experimental result. After then, to construct rule base in progressive blanking process, FE-simulation has been performed using a simple model. Based on this result rule base is set up and then the blanking order of inner lead is rearranged. Consequently, from the results of FE-simulation using suggested method in this paper, it is possible to predict the shift of lead to manufacture high precision lead frame in progressive blanking process. The proposed method can give more systematic and economically feasible means for designing progressive blanking process.

• Transactions of Materials Processing
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• v.14 no.3 s.75
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• pp.207-214
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• 2005

Blanking process is widely used fur producing various structural parts. However, fine blanking technology is frequently used as a single step blanking operation with clean cut surface of a sheared surface because the fractured surface of parts causes serious problems in the final product and therefore it must be removed by the post-processing in case of the conventional blanking. In the present investigation, a fine blanking process was designed within the framework of progressive die to produce a carrier plate assembled within the auto transmission. Finite element analysis of the shearing behavior at the respective stage of the progressive fine blanking was conducted to validate the designed die parameters. Finally the designed progressive fine blanking process was experimentally evaluated by using the machined die.

• Journal of the Korean Society for Precision Engineering
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• v.20 no.3
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• pp.35-41
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• 2003

The multihole blanking of thin sheet metal using progressive die set is an important process on production of precision electronic machine parts such as IC leadframe. In this paper, in order to investigate the influence of blanking order on the final lead profile and deformed configuration, simulation technique for progressive blanking process is proposed and analyzed by LS-DYNA. The results of FE-simulations are in good agreement with the experimental results. Consequently, from the results of FE-analysis based on the procedure proposed in this paper, it is possible to predict the deformation of lead and to manufacture high precision leadframes in progressive blanking process and these results might be used as a guideline to develop layout design system in multihole blanking process.

• Journal of the Korean Society of Manufacturing Technology Engineers
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• v.19 no.3
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• pp.407-413
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• 2010

This paper reports on the research which analyzes acoustic signals acquired in progressive compressing, hole blanking, and burr compacting process. An acoustic sensor was set on the bed of hydraulic press. Acoustic signal is generated from progressive stamping process. First the signal acquired from the unit process; compressing, blanking or compacting, is studied by Fourier Transform and Short Time Fourier Transform. The blanking process emitted ultrasonic signal with more than 20kHz, but the compressing and compacting processes emitted acoustic signals with lower than 10kHz. The combined signals periodically acquired right after the tool grinding were then analyzed. 70-80kHz signals appeared in time-frequency domain, but not in the frequency domain, the magnitude of which was related to the tool wear. Short Time Fourier Transform made up for the Fourier Transform in analyzing the emitted signal for stamping process in the ultrasonic domain.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2002.10a
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• pp.296-299
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• 2002

The precision blanking of thin sheet metal is important process on production of precision electronic machine parts such as IC leadframe. In the blanking process, the factors that friction coefficient, tool clearance, material properties are the most important factors in the precision blanking process, because these factors affect the sheared face of product, side forces to punch during blanking process and surface condition after blanking process. So, many investigations have been performed. But, the former studies did not take up the characteristic of material. In this paper, in order to investigate the characteristic of blank, such as K(strength coefficient) and n(strain hardening coefficient), on the sheared face of blank and the side force to punch, FE-simulation has been analyzed by means of DEFORM-2D. To obtain input Parameters on FE-simulation, tensile and friction test has been done.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 1996.11a
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• pp.182-186
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• 1996

In this work, a method is described to investigate the progressive and compound process in the coining and piercing operation for given conditions and parameters, using the FEM simulation and model experiment. The effect of the die shape on the compound process is established, and the die shape depends on the position of coining die and the width of the part coined. It is found that Progressive process is better than compound process, since material's filling into the die is not completed and the higher stress acts on the edge of the punch according to width being increased.

• Proceedings of the Korean Society for Technology of Plasticity Conference
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• 2006.05a
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• pp.288-291
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• 2006

Piercing or blanking process is widely used to manufacture most of lead frame parts, but it is difficult to analyze the real process by the actual shape through progressive dies. In this paper several stages in progressive punching are modeled by 2D and 3D configurations using $DEFORM^{TM}$ 2D/ 3D code. During the progressive stage some state variables and deformed configurations are analyzed in each model. There are three stages in the process, the deformations at each stage are cumulative. The advantages and disadvantages of these two type modeling are discussed and analyzed. The experiments are performed as a working material copper alloy through manufactured die. Computed results in load by two types are compared to experiments.

• Design & Manufacturing
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• v.2 no.3
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• pp.40-44
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• 2008

Shaving in sheet metal forming is defined as a finish process to make the sheared surface clean which was blanked or pierced in the previous shearing stage. In this study the new shaving technique is applied to the progressive operation. The specimen is automatically fed by continuous movement of the strip. Which improve the positioning accuracy higher. For this study a square part which consist of blanking and piercing is selected for investigation and the progressive die which includes pre-piercing, pierce-shaving, half-blanking and blank-shaving etc is prepared for specimens of steel sheet(SPCC) and aluminum alloy sheet(AL5052). Experiments are carried out for several working variables such as shaving allowance, pre-shearing clearance and relative half-blanking depth. Consequently it was confirmed that the shaving by progressive die can be successfully employed to produce the clean parts requiring shaving process and optimum working conditions for shaving SPCC and AL5052 sheet metal are shaving allowance of 0.2mm(1.3% of thickness) and pre-shearing clearance of 5%.

• Journal of the Korean Society of Manufacturing Technology Engineers
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• v.21 no.1
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• pp.167-174
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• 2012

For high production rate of parts requiring multiple operations such as punching, blanking, or other operations are generally done with progressive dies. However, progressive die is generally limited to use for sheet metal forming due to the technical difficulties in rod or bulk material. This study proposes a new technique of progressive die and forming process for asymmetric automotive door striker, which is conventionally manufactured with separate tandem processes using solid rod. In order to design forming process and die, FEM simulation was performed to divide proper intermediate processes and analyze its formability. As a result, Forming processes were divided into 3 stages with upper and side punches and also, workpiece feeding and location mechanism was designed and manufactured in this study. Finally, forming tryouts were carried out by using the manufactured progressive die to verify the forming quality and productivity.

• Journal of the Korean Society for Precision Engineering
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• v.13 no.8
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• pp.40-51
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• 1996

This paper describes some research works of computer-aided design of blanking and piercing progressive die for stator and rotor parts. An approach to the system is based on knowledge based rules. The deveolped system is composed of six modules such as main program, input and shape treatment, production feasibility check, strip layout, die layout and drawing edit module. Using this system, design parameters ( geometric shapes, die and punch dimensions and dimensions of tool elements) are determined and output is gen- erated in graphic from. Knowledges for tool design are extracted from the plasticity theories, handbooks, relevant references and empirical know-hows of experts in blkanking companies. The developed system provides powerful capabilities for process planning and die design of stator and rotor parts.