• Journal of the Korean Society for Precision Engineering
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• v.11 no.4
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• pp.77-87
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• 1994

This paper deals with an automated forming sequence design system by which designers can determine desirable operation sequences even if they have little experience in the design of cold forging process. The forming sequence design in the cold forging is very important and requires many kinds of technical and empirical knowledge. They system isproposed, which generates forming sequence plans for the multistage cold forging of axisymmtrical solid products. Since the process of metal forming can be considered as a transformation of geometry, treatment of the geometry of the product is a key in planning process. To recognize the geometry of the product section, section entity representation and primitive geometries were used. Section entity representation can be used for the calculation of maximum diameter, maximum height, and volume. Forming sequence for the part can be determined by means of primitive geometries such as cylinder, cone, convex, and concave. By utilizing this geometrical characteristics (diameter, height, and radius), the product geometry is expressed by a list of the priitive geometries. Accordingly the forming sequence design is formulated as the search problem which starts with a billet geometry and finishes with a given product one. Using the developed system, the sequence drawing with all dimensions, which includes the proper sequence of operations for the part, is generated under the environment of AutoCAD. Based on the results of forming sequence, process variables(strain, punch pressure, die inner pressure, and forming load) are determined.

• Transactions of Materials Processing
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• v.8 no.6
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• pp.591-603
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• 1999

A computer-aided process planning system for rotationally symmetric deep drawing products has been developed. The application for non-axisymmetric components, however, has been reported yet. Therefore, this study investigates process sequence design in deep drawing process and constructs a computer-aided process planning system for non-axisymmetric motor frame products with elliptical shape. The system developed consists of three modules. The first one os a 3-dimensional modeling module to calculate surface area for non-axisymmetric products. The second one is a blank design module that creates an oval-shaped blank with the identical surface area. The third one is a process planning module based on production rules that play the best important roles in an expert system for manufacturing. The production rules are generated and upgraded by interviewing with field engineers. Especially, drawing coefficient, punch and die radii are considered as main design parameters. The constructed system for elliptical deep drawing products would be very useful to reduce lead time and improve accuracy for production.

• Transactions of Materials Processing
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• v.5 no.1
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• pp.27-36
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• 1996

In this paper a computer-aided design system for axisymmetric deep drawing process will be described. An approach to the system is based on the knowledge based system. The system has been written in AutoLISP with personal computer. The system is composed of four main modules such as input geometrical design test & rectification and user modification. the system which aids designer provides powerful capabilities for the design of axisymmetric deep drawing process.

• Journal of the Korean Society for Precision Engineering
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• v.13 no.4
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• pp.43-52
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• 1996

This paper describes interactive computer procedures for design the forming sequences in cold forging. This system is implemented on the personal computer and its environment is a commercial AutoCAD system. The programming language. AutoLISP, was used for the configuration of the system. Since the process of metal forming can be considered as a transformation of geometry, treatment of the geometry of the part is a key in process planning. To recognize the part section geometry, the section entity representation, the section coordinate-redius representation and the section primitive geometru were adopted. This system includes six major modules such as input module, forging design module, forming sequence design module, die design module, FEM verification module and output module which are used independently or in all. The sequence drawing wigh all dimensions, which includes the dimensional tolerances and the proper sequence of operations, can generate under the environment of AutoCAD. The acceptable forming sequences can be verified further, using the FE simulation.

• Proceedings of the Korean Society for Technology of Plasticity Conference
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• 2000.10a
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• pp.132-135
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• 2000

A process design expert system for rotationally symmetric deep drawing products has been developed The application of the expert system to non-axisymmetric components, however, has not been reported yet. Thus, in this present study, the expert system for non-axisymmetric deep drawing products with elliptical shape was constructed by using process sequence design. The system developed in this work consists of four modules. The first one is a recognition of shape module to recognize non-axisymmetric products. The second one is three dimensional (3-D) modeling module to calculate the surface area for non-axisymmetric products. The third one is a blank design module to create an oval-shaped blank with the identical surface area. The forth one is a process planning module based on the production rules that play the best important role in an expert system for manufacturing. The production rules are generated and upgraded by interviewing with field engineers.

• Proceedings of the Korean Society for Technology of Plasticity Conference
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• 1994.10a
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• pp.107-117
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• 1994

A design methodology is applied for manufacturing a disk-brake piston component and a washing machine container. The design criteria are the limit drawing ratio and the forging load within the available press limit. Also, the final product should not have any geometrical defect. The rigid-plastic and elastic-plastic FEM have been applied to simulate both of the conventional manufacturing processes, respectively, which include deep drawing and forging process. Simulations of one stage process from a selected stock to the final product shape are performed for generating information on additional requirements for metal flow. The best manufacturing processes are selected, which is using a hemispherical punch in the deep drawing process for both disk-brake piston component and washing machine container.

• Proceedings of the Korean Society for Technology of Plasticity Conference
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• 1997.03a
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• pp.144-147
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• 1997

Process design of multi-step wire drawing process, conducted by means of finite element analysis and ANN(Artificial Neural Network), has been considered. The investigated problem involves the adequate selection of the drawing die angle and the correspondent reduction rate sequence in the condition of desired initial and final diameter. Combinations of the process parameters which are used in finite element simulation are selected by using orthogonal array. Also the orthogonal array and the results of finite element simulation which are related to the process energy are used as train data of ANN. In this study, it is shown that the new technique using ANN is useful method in application to the wide range of metal forming process.

• Journal of the Korean Society of Physical Medicine
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• v.11 no.2
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• pp.33-40
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• 2016

PURPOSE: The purpose of this study was to determine the impact of stable and unstable surfaces on abdominal muscle thickness and changes in trunk muscle thickness in accordance with breathing methods during bridging exercises. METHODS: Bridging exercise on a stable surface, bridging exercise on an unstable surface, bridging exercise using a drawing-in maneuver on a stable surface, bridging exercise using a drawing-in maneuver on an unstable surface, bridging exercise using bracing on a stable surface, bridging exercise using bracing on an unstable surface. In sequence, the muscles' thickness was measured three times before and after each exercise, and the measured value was averaged. RESULTS: There were significant differences in internal oblique and transversus abdominis muscles' thickness in the drawing-in maneuver in both stable and unstable surface (p<0.05). There were no significant differences in external oblique muscle's thickness in the bridging exercise in both stable and unstable surface. The type of surface did not have a significant influence on the abdominal muscles' thickness. CONCLUSION: As a result of the study, the drawing-in maneuver had a greater effect than bridging or bracing maneuver on muscle thickness. We suggest that drawing-in maneuver will be more effective in a person with a weak abdominal muscle.

• Proceedings of the Korean Society for Technology of Plasticity Conference
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• 2005.10a
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• pp.418-422
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• 2005

In this study, the die design and die series on the surface residual stress of cold drawn eutectoid steel wire has been investigated. Test pieces were fabricated using die series with different mean and final reduction ratio. Surface residual stresses in the axial direction were measured by X-ray diffraction, Broker's 2-dimensional GADDS system. Results were compared with stress profiles which were calculated by 3D and 2D finite element simulation, Hibbitt's ABAQUS 6.4 program in Finite Element Analysis. By means of FEA method, optimal die shape considering delta-parameter were induced and applied in order to determine die sequence designs. Balance of the drawing stresses was also introduced to optimize die sequence.

• Transactions of Materials Processing
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• v.15 no.2 s.83
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• pp.153-157
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• 2006

In this study, the die design and die series on the surface residual stress of cold drawn eutectoid steel wire have been investigated. Test pieces were fabricated using die series with different mean and final reduction ratios. Surface residual stresses in the axial direction were measured by X-ray diffraction, Bruker's 2-dimensional GADDS system. The results were compared with stress profiles that were calculated by 3D and 2D finite element simulations, ABAQUS 6.4 program in finite element analysis(FEA). By means of the FEA method, optimal die shape considering delta-parameter were induced and applied in order to determine die sequence designs. Balance of the drawing stresses was also introduced to optimize die sequence.