• Design & Manufacturing
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• v.17 no.4
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• pp.33-41
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• 2023

Excessive use of plastic bottles contributes to a significant environmental issue due to the high volume of plastic waste generated. To address this, efforts are needed to reduce the weight of plastic bottles. However, indiscriminate weight reduction may compromise the essential rigidity required for plastic bottles. Extensive research on rib shape for pressure vessels are exists, but there is a few research of rib shapes to enhance the stiffness of plastic bottles. The following results were obtained from the analyses conducted in this study. 1) Among the rib cross-sections of square, trapezoid, and triangle, the buckling critical load of PET bottles with square-shaped ribs is improved by about 14% compared to the buckling critical load of PET bottles without ribs. 2) The buckling critical load is improved by about 18% when a square-shaped rib with an aspect ratio of 0.2 is applied, compared to the buckling critical load of the bottle without the rib. 3) When longitudinal and transverse square ribs were applied to the axial direction of the PET bottle, the buckling critical load was improved by about 32% and 58% compared to the buckling critical load of the PET bottle without ribs, respectively, indicating that applying longitudinal ribs is effective in reinforcing the stiffness of PET bottles. 4) When 14 transverse ribs were applied, the maximum improvement was about 48% compared to the buckling critical load of the plastic bottle without ribs. 5) When 3 longitudinal ribs were applied on each side, the maximum improvement was about 76% compared to the buckling critical load of the bottle without ribs. Therefore, it was concluded that for effective stiffness reinforcement of a 500ml square bottle with a thickness of 0.5mm, 3 square-shaped ribs with an aspect ratio of 0.2 should be applied in the longitudinal direction relative to the axial direction of the bottle.

• The Journal of the Korea Contents Association
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• v.8 no.12
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• pp.190-197
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• 2008

Weaving design which is to be designed based on the machine words threading and treading is characterized by its strong limitation of expression. The concept of design has been set based on the patterns on the wooden rice-cake mold which arechosen from many Korean traditional patterns since the expressions of patterns limited by the wooden rice-cake mold is easy to be grafted upon each other. Particularly, literal patterns and geometrical patterns contain religious desire and wishes that are generated from man's fear and wonder about Nature rather than from the pursuit of beauty which is general characteristics of patterns. Based on these images, the twill technique, especially threading of Sally Nielson's rosepath which is easy in formal expressions is used to design Korean style patterns into the weaving structure. It is hoped that this study will provide an opportunity to introduce Korean style patterns to the weavers of the world and that the weaving designs will actively be utilized in the Korean industries so that they can acquire high value-added assets and commercialize our superior culture, thus being of great help to developing our cultural industr.

• Korean Chemical Engineering Research
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• v.48 no.4
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• pp.490-498
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• 2010

The optimum mold design and the optimum process condition were constructed upon executing process simulation of rubber injection molding with the commercial CAE program of MOLDFLOW(Ver. 5.2) in order to solve the process-problems of K company relating to air-traps and short-shots. The former occurs at the cavity edge of torque-rod-bush and the latter takes place for the injection molding of dynamic dampers. As a result the process problem relating to air traps was solved by optimizing edge-angle and the number of gates to prevent the flow congestion of flow-front and to make the flow-front movement unaffected by congestion. For dynamic dampers of K company the unmolded flaw caused by their unfilled cavity was corrected by installing the air-vent at the confronting locations of both upstream and downstream of flow-front where air traps frequently occur. Besides the unmolded flaws were rectified by altering the position of gate from the upper to the middle or by increasing the number of gates. Thus the process problems of K company relating to air-traps and short-shots of torque-rod-bush and dynamic dampers, respectively, were solved by proper altering of mold design with process simulation of rubber injection molding.

• Journal of the Korean Society of Manufacturing Technology Engineers
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• v.22 no.2
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• pp.248-255
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• 2013

The objective of this study is to optimize the Metal Injection Molding(MIM) process with design of experiments(DOE) and numerical analysis. To derive the optimal process condition, experiment or numerical analysis was performed under various process conditions. To analyze the interaction among influential factors contributing to the temperature at flow front and response surface in MIM, both central point and axial point were added to the full factorial design with 2 levels and 5 factors and then their impacts on response variable in 43 experimental conditions were analyzed and the significance was evaluated. As a result, sprue, runner, and gate were completely filled in about 0.247 seconds after injection, the front part of the green body was filled in about 0.3344 seconds, the green body except gate, etc changed to almost solid state in about 3.29 seconds, the Packinging pressure was completed in about 6.29 seconds, and the green body inside and outside and sprue, etc became solid in 13.2 seconds. The impact of individual or reciprocal action of factors on the temperature at flow front was analyzed through regular probability, test statistics, main effect, and interaction effect. As a result, of a total of 31 combinations of factors, 9 unit factors and reciprocal actions were significant, and the screening was also possible. A proper regression equation was drawn with regression analysis and response surface design on the response variable of temperature at flow front, and the applicability could be verified.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.41 no.6
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• pp.553-560
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• 2017

3D printing technology has been a great interest in human bio-interfaces and human-like robotics since they require arbitrary and adaptive manufacturing. This research mainly concerns the 3D fabrication of a packed biosensor using elastomeric sheets made of PDMS. It is essential to design the PDMS molding with 3D printing since, in the case of biosensors, it should not only produce a conformal shape depending on an arbitrary skin surface but also guarantee a uniform thickness distribution during solidification in the PDMS prepolymer solution. To satisfy the characteristics of the PDMS molding, such as flexibility in the de-molding and stiffness in the solidification processes, multi-materials have been selectively applied to the PDMS molding design, which has been validated with finite element analyses and compared with the 3D printed molding.

• Design & Manufacturing
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• v.14 no.3
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• pp.23-30
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• 2020

Laser Assisted Thermo-Compression Bonding (LATCB) has been proposed to improve the "chip tilt due to the difference in solder bump height" that occurs during the conventional semiconductor chip bonding process. The bonding module of the LATCB system has used a piezoelectric actuator to control the inclination of the compression jig on a micro scale, and the piezoelectric actuator has been directly coupled to the compression jig to minimize the assembly tolerance of the compression jig. However, this structure generates a lateral force in the piezoelectric actuator when the compression jig is tilted, and the stacked piezoelectric element vulnerable to the lateral force has a risk of failure. In this paper, the optimal design of the flexure hinge was performed to minimize the lateral force generated in the piezoelectric actuator when the compression jig is tilted by using the displacement difference of the piezoelectric actuator in the bonding module for LATCB. The design variables of the flexure hinge were defined as the hinge height, the minimum diameter, and the notch radius. And the effect of the change of each variable on the stress generated in the flexible hinge and the lateral force acting on the piezoelectric actuator was analyzed. Also, optimization was carried out using commercial structural analysis software. As a result, when the displacement difference between the piezoelectric actuators is the maximum (90um), the maximum stress generated in the flexible hinge is 11.5% of the elastic limit of the hinge material, and the lateral force acting on the piezoelectric actuator is less than 1N.

• Polymer(Korea)
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• v.38 no.6
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• pp.708-713
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• 2014

Most plastics products are being produced by injection molding process. However, mold shrinkage is inevitable in injection molding process and it deteriorates dimensional quality through deflections and warpages. Mold shrinkage depends upon the material property of resin as well as injection molding condition. In this study, material property of resin has been predicted for glass fiber reinforced polycarbonate to control the warpage, and computer simulation of injection molding has been performed using predicted property. It was observed that the deflection of part decreased by the glass fiber reinforced resin. In order to verify the validity of this method and confidence of results, experiments of injection molding were performed. The results of experiments and computer simulations showed good agreement in their tendency of deflections. Consequently, it was concluded that the method of designing the material property of resin conducted in this study can be utilized to control the dimensional accuracy of injection molded products.

• Korean Journal of Computational Design and Engineering
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• v.9 no.2
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• pp.112-121
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• 2004

As customers demands are rapidly changing, a product life cycle is getting shorter and a product model is forced to be changed frequently. An ejecting design system becomes more important for high productivity to eject a product in high temperature without any damage. For example, an ejector pin that is a key component of the system can cause high local stresses and strains in the molding at the time of ejection. The number, the size, and the location of pins are important to make a smooth ejection. Therefore we propose an analytical approach with the aid of designer’s experience to calculate a total release force and pressure distribution so that the number, the size, and the location of pins can be easily determined. As a part of the result, the design system is built by Intent! with AutoCAD 2000 and a video player deck example is presented to verify the approach.

• Proceedings of the Korean Society for Technology of Plasticity Conference
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• 2003.04a
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• pp.33-39
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• 2003

Injection molding is widely used in producing various plastic parts due to its high productivity and the demand for high precision injection molded products is ever increasing. To achieve successful product quality and precision, the design of gating and runner systems in the injection mold is very important since it directly influences melt flow into the cavity. Some defects such as weld lines and overpacking can be effectively controlled with proper selection of gate locations. In the present study, the design of gate locations in injection molding of a dashboard for automobiles was carried out with CAMPmold, a PC-based simulation system for injection molding. A dummy runner was developed to simulate a runner system in order to increase the efficiency of the analysis. The numbers and locations of gates were varied in the present investigation as that an acceptable design was obtained in terms of reduced maximum pressure and clamping force.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2002.05a
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• pp.591-594
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• 2002

In this study, we develop automatic design program, which create 3D model of spur gear and helical gear used VisualLISP and create helical gear in the CATIA using 2D profile of gear. This model become the standard models which give not only in itself mold information but also compare processed product with measuring date. Spur gear require mathematical examination of involute curve and trocoidal fillet curve. Automatic design program, which have a mathematical development create the profile of spur gear.