• Proceedings of the Korean Society for Technology of Plasticity Conference
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• 2004.05a
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• pp.66-69
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• 2004

A new concept of multi-point dieless elasto-forming method has been developed to make various shape of curved surface without conventional dies. The developed dieless elasto-forming system consists of discrete punches controlled by servo motors and various kinds of elastomers(rubber and foam). To predict optimal position of punch elements, DTF(deformation transfer function) was introduced, and FEM analysis was carried out. The optimal arrangement of elastomer was selected considering characteristics of each elastomer, and a desired concave shape was formed. The experimental results were consistent with the numerical ones.

• Proceedings of the Korean Society for Technology of Plasticity Conference
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• 2002.05a
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• pp.58-61
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• 2002

A new concept of dieless sheet forming technology is proposed in this study to overcome the drawback of conventional dieless forming technology. For this purpose, dual points contact of the conventional punch system, which is a primary cause of surface defects, is replaced to single point contact using technology combined with fluid forming. It is expected that the advanced system may lead to easy displacement control of multi-punch elements, reducing surface defects, and increasing decision and forming limits. The reduced number of punch elements also saves the cost of the equipment. In addition, the new technology can be utilized for deep drawing as well as two- or three-dimensional curved surface forming, and thereby become multi-functional and multi-purpose differently from the conventional technology.

• Journal of the Korean Society of Manufacturing Process Engineers
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• v.6 no.4
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• pp.36-43
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• 2007

Dieless CNC forming is an innovative technology which can form various materials with complex shape by numerically controlled incremental forming process. In order to apply the technology to industrial parts, however, many problems such as spring-back, rising of material, and trimming difficulty must be solved. In this paper a new dieless CNC forming method to improve forming quality is proposed, which consists of how to modify its original shape in CAD and how to generate its CNC tool path in CAM. The effectiveness of the proposed procedures is tested with a brake dust shield of a vehicle. The results shows that the method proposed enhances the forming quality up to 48% compared to traditional method.

• Proceedings of the Korean Society for Technology of Plasticity Conference
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• 2008.05a
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• pp.220-223
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• 2008

Large curved plate blocks are widely used to construct hull structure in shipbuilding industry. Most curved plates are manufactured by using manual method called as line heating that use deformation caused by residual stress after local heating along a line which is perpendicular to the curvature direction. However, its working environment is poor and its formability is totally dependent on an experienced technician. In view of that, multi-point dieless forming (MDF) technology that use reconfigurable punch arrays instead of one piece die is proposed in this study. The MDF process is based on a concept of equivalent die surface made by numbers of punches which has round tip at the end of it. In this study, numerical simulation for common curvature type such as saddle shape was carried out. In addition, experiments in the plate forming process were also conducted to compare with the numerical results in view of final configuration. Consequently, it was noted that the proposed dieless forming method has considerable feasibility to substitute the new process for conventional manual method.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2006.10a
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• pp.487-488
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• 2006

• Proceedings of the Korean Society for Technology of Plasticity Conference
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• 2005.10a
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• pp.152-155
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• 2005

A method of three-dimensional curved surface generation was studied for multi-point dieless forming (MPDF) in the shipbuilding industry. Three-dimensional coordinates of punch elements were obtained from objective surfaces using a proprietary CAD program. MPDF surfaces were generated by adjusting the height of punch elements in accordance with the coordinates. Some problems, such as collision of punch elements and contact between plates and punch bodies, were anticipated from the analysis of the results. A twisted surface was formed successfully by MPDF in a laboratory scale, which suggests possibility of application of the technology to the shipbuilding industry.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2005.06a
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• pp.1753-1756
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• 2005

The sheet parts are formed with dies conventionally. But this conventional forming process is not suited to small volume and varied production for the reason of high cost. For the solution of this problem, a new forming process, which is called CNC incremental sheet forming, is being introduced. This process can form sheet parts without die, and is very well suited to small volume and varied production in space flight and automobile. In this paper, dieless CNC forming system based on a machining center is developed. A special device to grasp and pull the blank sheet built in the machining center and tool path generation S/W from STL file of 3-D model are developed. Several sheet parts are incrementally formed to verify the effectiveness of the developed system.

• Transactions of Materials Processing
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• v.29 no.2
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• pp.76-88
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• 2020

The need for advanced high strength steel (AHSS) forming technology is increasing as interest in light weight and safe automobiles increases. Multipoint dieless forming (MDF) is a novel sheet metal forming technology that can create any desired longitudinal and transverse curvature in sheet metal. However, since the springback phenomenon becomes larger with high strength metal such as AHSS, predicting the required MDF to produce the exact desired curvature in two directions is more difficult. In this study, a prediction model using artificial neural network (ANN) was developed to predict the springback that occurs during AHSS forming through MDF. In order to verify the validity of model, a fit test was performed and the results were compared with the conventional regression model. The data required for training was obtained through simulation, then further random sample data was created to verify the prediction performance. The predicted results were compared with the simulation results. As a result of this comparison, it was found that the prediction of our ANN based model was more accurate than regression analysis. If a sufficient amount of data is used in training, the ANN model can play a major role in reducing the forming cost of high-strength steels.

• Proceedings of the Korean Society for Technology of Plasticity Conference
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• 2007.05a
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• pp.281-281
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• 2007

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2006.05a
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• pp.529-530
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• 2006

Manufacturing industry is changing rapidly. Prototyping with rapid manufacturing is a part of every business in many companies and prototypes are used efficiently as a part of the production development process. Sheet metal forming has traditionally been a technology area where prototyping has been extremely expensive and efficient options for low volume have been limited. This paper describes the process for incremental sheet forming technologies to make the prototype for a brake dust shield of vehicles, which includes the remodeling method to make a base mold and tool path for sheet metal forming and 5-axes laser cutting machine to trim the prototype product.