• Proceedings of the Korean Society for Technology of Plasticity Conference
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• 2002.02a
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• pp.308-315
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• 2002

In recent automotive industries, fine blanking technology widely used in production of components with relatively thick gauges in brake systems, seat recliner, door locks, and auto transmission systems. Due to its advantages to obtain almost final product quality using fine blanking forming process without additional finish machining processes, consequently saving the production costs. In this paper we intended to develope the small sized module gear toothed dual seat recliner sector gear(0.5mm module) for car seats using fine blanking process which needed semi piercing with computer simulation and a lot of try and errors to achieve required accuracy and geometric quality. However through the some corrections of tool geometries with tryout test, we could get successful results.

• Transactions of the Korean Society of Automotive Engineers
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• v.17 no.1
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• pp.64-71
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• 2009

The development of more safe recliners is an important issue in the automotive industry. However, the development of new recliners is costly and take much time because it is typically based on experimental evaluation using prototypes. This study presents the evaluation of rear crashworthiness for round recliner using finite element method. That reduces the number of repeating test and gives an information about stiffness. To evaluate rear crashworthiness, the FMVSS 301 simulation and pendulum impact simulation were performed. The load path on two simulations was observed and compared each other in this paper. Also stress, strain and internal energy was compared. It is attempted the tooth strength simulation using a substructure option on PAM-CRASH.

• Journal of the Korean Society for Precision Engineering
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• v.25 no.7
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• pp.64-71
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• 2008

Burr generated on plate holder should be removed through additional process, because it has an influence on the function of automotive seat recliner. The process layout to perform simultaneously embossing and half blanking of plate holder has been developed in this study in order to minimize the influence of burr formation. The optimal process condition to satisfy the required dimensional accuracy of plate holder has been determined using Taguchi method and finite element analysis. It has been shown from experimental results that the proposed method is decidedly superior to the previous FCF method from the aspect of sheared surface, roll-over, flatness and burr height.

• Journal of the Korean Society of Manufacturing Process Engineers
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• v.9 no.1
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• pp.99-105
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• 2010

This study was performed to solve the breaking problem in the fine blanking(FB) process of sector gears for car seat recliner using nickel chrome molybdenum steel(SNCM220) plate. The optimal design of embossing circle is changed to oval with labors' experiences and finite element analysis. The maximum principal stress and effective strain in a forming process are analyzed by commercial finite element software to solve the problems in embossing stage of FB process. As a result of FE analysis, the maximum principal stress in forming is lower than yield point of material. It is shown from experiments in the modified die that the formed gear does not break in embossing stage.

• Transactions of Materials Processing
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• v.20 no.3
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• pp.214-221
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• 2011

In recent years, automotive seat components have been manufactured by the fine blanking process, allowing an improvement of dimensional accuracy at sheared surface in series production. However, the rollover has increased and die failures have occurred more frequently when manufacturing gears by fine blanking. Consequently, important goals for manufacturing seat recliner parts with gears have been to decrease the rollover as well as to improve the tool life. In this study, the half blanking and shaving processes were introduced to improve aforementioned problems for the lower tooth, the main component of a seat recliner. For this purpose, the half blanking process was optimized using the finite element (FE) analysis and design of experiment (DOE). The optimized conditions resulting from this study were an offset of 0.2 mm, a clearance of 0.1 mm and a penetration depth of 4.5 mm. Fine blanking experiment conducted under the optimal condition resulted in a rollover depth decrease from 1.9 to 1.3 mm, and no die failure occurrence.

• Transactions of Materials Processing
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• v.25 no.4
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• pp.268-274
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• 2016

In the automotive seat industry, the use of a fine blanking press is important for manufacturing of high precision products. Among them, a gear part which is a main component of an automotive seat recliner is generally manufactured by fine blanking press. However, the use of conventional mechanical press has been increasing in manufacture of gear part because of low productivity of fine blanking press. In this study, new forming process is suggested to fabricate the gear part with high precision by using mechanical press. The effect of flow restriction die (FRD) which has the restriction of blank edge on dimensional accuracy is investigated by FE-analysis. FE-analysis results for different conditions of FRD indicated that FRD has high dimensional accuracy with the lowest roll-over and the highest perpendicularity of gear part. After application to fabrication of the gear part using mechanical press, the measured dimensional characteristic was compared with the required specification of final product. In addition, results of the performance test showed that the product fabricated by developed process satisfied the required strength and durability. The results show that the suggested forming process by using FRD and mechanical press can replace fine blanking on the viewpoint of dimensional accuracy and productivity.

• Journal of the Korean Society for Precision Engineering
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• v.25 no.7
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• pp.55-63
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• 2008

Fine blanking is a process of press shearing which makes it possible to produce the thick sheet metal of the finished surface and the close dimensional accuracy over the whole material thickness in the single blanking operation. In this paper, a plate holder of automotive seat recliner is manufactured by FCF(Flow Control Forming) method using the conventional mechanical press instead of the fine blanking press. Main processes for manufacturing of the plate holder by FCF method are embossing, half blanking and trimming processes. Optimal clearance, stripper force and counter force to increase the dimensional accuracy of the plate holder have been investigated by FE-analysis. As a result of FE-analysis, the clearance for both embossing and half blanking processes was -2%t and the forces of stripper and counter were 25ton and 15ton, respectively. After manufacturing the plate holder by FCF method, the measured dimensional characteristics have been compared with the required specifications as the final product. Although the dimensional accuracy of the plate holder manufactured by FCF method was a little inferior to that by fine blanking process, it was satisfactory in a general sense.

• Journal of the Korean Society of Manufacturing Process Engineers
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• v.15 no.2
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• pp.22-30
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• 2016

It is very important to obtain the net shape of the product to maximize the shear cutting surface of fine blanking. In this paper, the fine blanking die was manufactured to achieve part characteristics, such as flatness and a fully sheared surface. The V-ring in the fine blanking die was designed to prevent lateral movement of the material. The fine blanking experiment was conducted with the fine blanking die. The material usage rate was increased by over 5.7% and that of the water-soluble lubricant was decreased by over 33% when the 2-cavity die technology was applied to fine blanking. The capacity of the existing press could lead to productivity improvement and cost reduction. Thus, 2-cavity die technology for fine blanking with a minute module of an accurate gear for producing seat recliner parts was developed.

• Journal of Power System Engineering
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• v.15 no.6
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• pp.53-58
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• 2011

To optimization of mlod for fineblanking forming of sector gear of recliner, it was analyzed the effect of clearance, V-ring height, V-ring position, blank holding force and counter punch force. In case of 0.003 mm of clearancs, the finest shear plane was obtained, but optimization between die and punch clearance was 0.005 mm. The height of V-ring was 0.7 mm. In case of increasing of hold force, the size of shear plane got better and the decrement of thickness became smaller. Both the size of shear plane and the decrement of thickness increased according to increasing of counter punch force.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.34 no.11
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• pp.1623-1630
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• 2010

In this study, effective forming methods for reducing the roll-over of a sector tooth, which is a main component of an automotive seat recliner, are proposed. Due to the large amount of roll-over, accurate contact between the inner gear of a sector tooth and the outer gear of a pawl tooth cannot be normally achieved; thus sensitivity and safety for the passengers decrease. To overcome the aforementioned drawback, we investigated the effect of flowcontrol forming methods involving local embossing die, coining punch, and VIC (Variable Inverse Clearance) on the roll-over depth by FE-analysis and an experiment. The results of a fine-blanking experiment for verifying the proposed methods showed that VIC type is decidedly superior from the aspects of reduction of roll-over and tool strength of the sector tooth.