• Transactions of Materials Processing
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• v.9 no.2
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• pp.165-170
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• 2000

In this paper, a general approach to structural analysis of forging die sets is presented and the related design system, AFDEX/DIE, is introduced. Structural analysis of die sets is conducted by the finite element method considering both contact problem and shrink fit. In the approach, amount of shrink fit is controlled by thermal load, i.e., temperature difference between die insert and shrink rings. The loading conditions are extracted automatically from the simulation results obtained by a rigie-thermoviscoplatic finite element method. Typical application examples are given, which show the applicability of the approach and the related program.

• International Journal of Precision Engineering and Manufacturing
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• v.7 no.1
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• pp.3-8
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• 2006

This paper deals with an automated computer-aided process planning and die design system by which designer can determine operation sequences even if they have a little experience in process planning and die design for axisymmetric products. An attempt is made to link programs incorporating a number of expert design rules with the process variables obtained by commercial FEM softwares, DEFORM and ANSYS, to form a useful package. The system can provide a flexible process based on either the reduction in the number of forming sequences by combining the possible two processes in sequence, or the reduction of deviation of the distribution on the level of the required forming loads by controlling the forming ratios. Especially in die design module optimal design technique and horizontal split of die insert were investigated for determining appropriate dimensions of components of multi-former die set. Results obtained, using the modules, enable the design and manufacture of a die set for a multi-former to be more efficiently performed.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2002.10a
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• pp.713-716
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• 2002

The dimensional accuracy of the cold forged products is strongly dependent on the elastic behavior of the die. The elastic deformation of the die is continuously changed during the process. Therefore, it is needed to measure the deformation of die. Strain gauges are used to measure the elastic strains in the die during cold backward extrusion process. The strain gauges are attached on the die surface and embedded at the interface between the die insert and the stress ring. In order to compare the results with the FE-analysis, the rigid-plastic FE-analysis of cold backward extrusion process using DEFORM-3D has been performed, and the analysis of elastic deformation of the die has been done by using ANSYS with non-linear contact.

• Design & Manufacturing
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• v.14 no.1
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• pp.15-21
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• 2020

Smart systems in different application areas such as automotive, medical and consumer electronics require a novel manufacturing method of electronic, optical and mechanical functions into products. Traditional methods including mechanical assembly, bonding of plastic and electronic circuit cause the problems in large size of products and complicated manufacturing processes. In this study, thermoforming and film insert molding were applied to fabricate a dome shaped plastic part embedded with electronic circuits. The deformation of patterns printed on PET film was predicted by thermoforming simulation using T-SIM, and the results were compared with those by experiment. In order to decrease spring-back after thermoforming, the Taguchi method of design of experiment was used. Through ANOVA analysis, it was found that mold temperature was the most dominant parameter for spring-back. By using flow analysis, gate design was performed to decrease injection pressure. During film insert molding, the wash-out of ink printed on film occurred for Polycarbonate. When the resin was changed to PMMA, the wash-out disappeared due to low melt temperature.

• Design & Manufacturing
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• v.12 no.2
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• pp.5-10
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• 2018

Vacuum-assisted thermoforming is one of the critical steps for successful application of film insert molding(FIM) to parts of complex shape. In this study, the simulations and experiments of thermoforming processes were performed to investigate the effects of process conditions on thickness distribution and printed pattern deformation of films in vacuum-assisted thermoforming. The film thickness uniformity increased with decreasing film heating time, whereas it increased with increasing vacuum delay time. After thermoforming of films with uniform pattern space of 5mm, the maximum space was 9.432mm. Based on the simulation, a modified pattern was calculated to obtain uniform spaces after thermoforming. In the experiments for film with the modified pattern, the maximum space appeared 5.837mm. In, addition. the predicted patterns were in good agreement with the experimental results.

• 한국금형공학회:학술대회논문집
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• 2008.06a
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• pp.69-73
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• 2008

본 연구에서는 고분자 플라스틱 부품의 친환경 외장성형공법인 Insert Film 사출성형공법중 첫 번째 공정인 진공성형공정에서 진공금형의 표면온도 균일화 기술에 대해 연구를 수행하였다. 진공금형의 온도분포 균일화를 위한 금형설계 및 설계된 금형에 대한 온도분포 평가를 위한 ANSYS를 이용한 유한요소열해석을 수행하였으며, 이때 정상상태 및 과도상태를 함께 평가하였다. 설계 결과를 바탕으로 금형을 제작하였으며, 생산성을 고려하여 4캐비티로 제작된 금형에 대해 금형표면의 온도분포 평가실험을 수행하였다. 또한 금형내 캐비티 온도센서 및 제어시스템을 설치하여 진공금형표면 온도분포가 항상 일정하게 유지될 수 있도록 금형시스템을 개발하였다. 결과적으로 일정한 온도범위의 금형표면온도제어가 가능하였다.

• Proceedings of the Korean Society for Technology of Plasticity Conference
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• 2003.05a
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• pp.19-22
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• 2003

In this study, the design of prestressed die for spur gear forging have been investigated. The stress concentration at notch of the die insert is very important in the design of die for the forging of spur gear such as non-axisymmetric geometry. In the previous study, the flexible tolerance method was used in order to search the optimal value of design variables considering the constrain conditions. In the design process, it was also involved the safety factor to the yield strength of each ring by considering allowable tensile or compressive hoop stress in each ring. Using this technique, the die deign for spur gear forging has been successfully performed without yielding of the die after shrink fitting and during forging.

• Journal of the Korean Society for Precision Engineering
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• v.18 no.3
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• pp.40-46
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• 2001

An integrated analysis for the thermo-elastic deformation, fatigue, wear and brittle damage evolution of the shrink-fitted die with multi stress-ring of dissimilar materials is presented. A simple numerical algorithm for the moving elastic boundaries characterizing the contacts of the insert and multi stress-rings is presented. The initial stress distribution in the die due to shrink-fit is considered and the traction at the die surface contacting with the work piece is obtained by analyzing the elasto-plastic deformation of work piece. Elastic analysis of the separate-type die is performed and then the evolution of brittle damage, wear and fatigue life are predicted. This integrated analysis is applied to the extrusion die with two layers of stress-rings and the results are discussed in detail.

• Journal of the Korean Society for Precision Engineering
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• v.16 no.11
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• pp.74-80
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• 1999

In this study, a stereolithography apparatus (SLA) prototype is used as a master model to be transformed into the silicone pattern by vacuum tool forming. The tool for the first prototype is fabricated by using this silicone pattern. Following this procedure, a temporary tool with metal powder and epoxy for wax injection is prepared for the die set of quick change type which consists of upper and lower base die나 and an insert die. The die set of quick change type appears to be very effective in casting operation by changing tools rapidly. The original wax pattern is formed through the die set, and is made of lost-was. Finally the lost-wax pattern is applied to investment casting. The final casting product is checked regarding its dimensional accuracy.

• Design & Manufacturing
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• v.18 no.2
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• pp.35-40
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• 2024

Injection molding is a process widely used across various industries for molding plastics, and it is the most commonly applied process in root industries utilizing molds. Among the different types of injection molding, insert injection molding, where busbars are used as inserts, is increasingly being applied in the electric vehicle industry. However, currently, the insert injection molding process is manually performed, with workers placing insert components by hand before injection molding. This results in issues related to productivity, safety, and quality. Additionally, there is a growing demand for automation of such production lines due to hazardous working conditions, economic difficulties in the manufacturing industry, and the decline in the labor force caused by an aging population. This study focuses on the application of an automated system for the insert injection molding process used in electric vehicles. The development of an automated system for the transport and insertion of insert components, as well as the inspection and stacking processes after injection, has resulted in over a 25% improvement in productivity and more than a 27% reduction in defect rates.