• Journal of the Korean Society for Precision Engineering
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• v.23 no.3 s.180
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• pp.118-124
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• 2006

The characteristic of sheet metal process is the few loss of material during process, the short processing time and the excel lent price and strength. The sheet metal process with above characteristic is common used in industrial field, but in order to analysis irregular field problems the reliable and economical analysis method is demanded. Finite element method is very effective method to simulate the forming processes with good prediction of the deformation behavior. Among Finite element method, the static-implicit finite element method is applied effectively to analyze real-size auto-body panel stamping processes, which include the forming stage. In this paper, it was focused on the drawing ability factors on auto-body panel stamping by AUTOFORM with using tool planning alloy to reduce law price as well as high precision front Design Optimization of die. According to this study, the results of simulation will give engineers good information to access the Design Optimization of die.

• Transactions of Materials Processing
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• v.27 no.2
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• pp.81-86
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• 2018

In the cold forming process, it is not easy to fabricate a asymmetric type nut, due to the difficulty in the exact prediction of metal-flow. As we have identified, in that case, it often results in the various forging defects such as burrs, and an incomplete shape, as well as other problems because of this issue. In the current study, we introduce the development of an unparalleled shape Weld Nut by using a forging analysis tool (AFDEX). For the multi-forming machine, the optimized shapes of each intermediate product (step product) could be found by the use of a model for the prediction and analysis of various types, sizes and heights. Chiefly, forging tools were prepared based on the simulation results and an unparalleled shape could be prepared at one time without any burrs, incomplete shape and size.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2010.05a
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• pp.213-214
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• 2010

• Proceedings of the Korean Society for Technology of Plasticity Conference
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• 2009.05a
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• pp.37-37
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• 2009

• Proceedings of the Korean Society for Technology of Plasticity Conference
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• 2008.10a
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• pp.122-125
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• 2008

Generally, in shipbuilding, large curved block components which have large curvature radius along various directions are used for huge ships such as LPG-vessel and oil tanker ships. Lots of the blocks are manufactured by line heating method which uses a heat source to bend the thick plate materials. The conventional forming process is entirely dependent on the experience of experts because it is done by manual method thus the curvatures and qualities are not uniform even for same part. However, it is hard to adopt the press forming process using die tool sets fur the manufacturing because of the characteristics of the industry that based on the small quantity and variety in the products. In this study, flexible forming technology using numbers of punches is investigated based on the simulation to substitute for the conventional forming method. Thick plate material model was applied to the proposed process to verify the feasibility for hull structure block forming process. The press forming processes were simulated by adopting the explicit-to-implicit sequential solution. Moreover, experiment of the flexible forming process was also conducted and its results were compared with that of simulation.

• Transactions of Materials Processing
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• v.22 no.5
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• pp.243-249
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• 2013

The multi-point forming (MPF) process for three-dimensional curved sheet metal has been developed as an alternative to the conventional die forming process since MPF allows the manufacturing of various shapes using one die set and reduce the cost of production. However, the MPF process cannot provide high quality products yet due to defects occurring in the sheet such as dimples and wrinkles. It can also lead to economic loss because of long tool setup time and additional machining required outside of the sheet formed area. In this study, a new sheet metal forming method, called flexible roll forming (FRF), is proposed to solve the problems of existing processes for three-dimensional curved sheet metal. This progressive process utilizes adjusting rods, as well as upper and lower flexible rollers as forming tools. In contrast with the existing processes, FRF can reduce the additional production costs because of the possible blank size for the part longitudinal direction, which is unrestricted. In this research, methods and procedures of the flexible roll forming technology are described. Numerical forming simulations of representative three-dimensional curved sheet products are also carried out to demonstrate the feasibility of this technology.

• Transactions of Materials Processing
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• v.19 no.3
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• pp.167-172
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• 2010

Roll-to-roll forming process is one of important metal processing technology because the process is simple and economical. These days, with these merits, roll-to-roll forming process is tried to be employed in manufacturing the circuit board, barrier ribs and solar cell plate. However, it is difficult to apply to the forming of micro scale or sub-micro scale pattern. In this study, the roll forming processing for the micro scale is designed and analyzed. The forming of micro pattern for small electric device such as LCD panel by incremental roll forming process is analyzed. Firstly, the optimum analysis conditions are found by several analyses. And then, formability is analyzed for various protrusion shapes at various forming temperatures. The formability is evaluated in terms of filling ratio and damage value. The filling ratio is defined from the tool geometry and critical damage is determined from the analysis of uniaxial tensile test. Finally, optimum forming conditions that guarantee the successful forming are found.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.21 no.1
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• pp.560-567
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• 2020

Incremental Sheet Forming (ISF) is a unique sheet-forming technique. The process is a die-less sheet metal manufacturing process for rapid prototyping and small batch production. In the forming process, the critical parameters affecting the formability of sheet materials are the tool diameter, step depth, feed rate, spindle speed, etc. This study examined the effects of these parameters on the formability in the forming of the varying wall angle conical frustum model for a pure Al3004 sheet with 1mm in thickness. Using Minitab software based on Back Propagation Neural Network (BPNN) and Genetic Algorithm (GA), a second order mathematical prediction model was established to predict and optimize the wall angle. The results showed that the maximum forming angle was 87.071° and the best combination of these parameters to give the best performance of the experiment is as follows: tool diameter of 6mm, spindle speed of 180rpm, step depth of 0.4mm, and feed rate of 772mm/min.

• Transactions of Materials Processing
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• v.7 no.3
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• pp.282-290
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• 1998

In bulk metal forming processes prediction of tool life is very important for saving production cost and achieving good material properties. Generally the service life of tools in metal forming process is limited to a large extent by wear, fracture and plastic deformation of tools. In case of hot and warm forging processes tool life depends on wear over 70%. In this study finite element analyses are con-ducted to warm and hot forging by adopting suggested wear model. By comparison of simulation and eal profile of die suggested wear model. By comparison of simulation and real profile of die suggested model is verified.

• Transactions of Materials Processing
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• v.7 no.3
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• pp.274-281
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• 1998

The service life of tools in metal forming process is to a large extent limited by wear, fatigue fracture and plastic deformation. In elevated temperature forming processes wear is the predominant factor for tool operating life. To predict tool life by wear Achard's model is generally applied. Usually hardness of die is considered to be a function of temperature. But hardness of die is a function of not only tem-perature but also operating time of die. To consider softening of die by repeated operation it is necessary to express hardness of die by a function of a function of temperature and time. By experiment of reheating of die softening curve was obtained and applied to suggest modified Archard's Model in which hardness is a function of main tempering curve.