• Journal of the Korean Society for Precision Engineering
• /
• v.16 no.6
• /
• pp.52-57
• /
• 1999

Funtional metal prototypes are often required in numerous industrial applications. These components are typically needed in the early stage of a project to determine form, fit and function. Recent R/P(Rapid Prototyping) part are made of soft materials such as plastics, wax, paper, these master models cannot be employed durable test in real harsh working environment. Parts by direct metal rapid tooling method, such as laser sintering, by now are hard to get net shape, pores of the green parts of powder casting method must be infiltrated to get proper strength as tool, and new type of 3D direct tooling system combining fabrication welding arc and cutting process is reported by song etc. But a system which can build directly 3D parts of high performance functional material as metal part would need long period of system development, massive investment and other serious obstacles, such as patent. In this paper, through the rapid tooling process as silicon rubber molding using R/P master model, and fabricate wax pattern in that silicon rubber mold using vacuum casting method, then we tranlsated the wax patterns to numerous metal prototypes by new investment casting process combined conventional investment casting with rapid pototyping & rapid tooling process. with this wax-injection-mold-free investment casting, we developed new investment casting process of fabricating numerous functional metal prototypes from one master model, combined 3-D CAD, R/P and conventional investment casting and tried to expect net shape measuring total dimension shrinkage from R/P part to metal part.

• Journal of Korean Society of Industrial and Systems Engineering
• /
• v.42 no.1
• /
• pp.1-7
• /
• 2019

In the modern industrial period, the introduction of mass production was most important progress in civilization. Die-casting process is one of main methods for mass production in the modern industry. The aluminum die-casting in the mold filling process is very complicated where flow momentum is the high velocity of the liquid metal. Actually, it is almost impossible in complex parts exactly to figure the mold filling performance out with the experimental knowledge. The aluminum die-castings are important processes in the automotive industry to produce the lightweight automobile bodies. Due to this condition, the simulation is going to be more critical role in the design procedure. Simulation can give the best solution of a casting system and also enhance the casting quality. The cost and time savings of the casting layout design are the most advantage of Computer Aided Engineering (CAE). Generally, the relations of casting conditions such as injection system, gate system, and cooling system should be considered when designing the casting layout. Due to the various relative matters of the above conditions, product defects such as defect extent and location are significantly difference. In this research by using the simulation software (AnyCasting), CAE simulation was conducted with three layout designs to find out the best alternative for the casting layout design of an automotive Oil Pan_BJ3E. In order to apply the simulation results into the production die-casting mold, they were analyzed and compared carefully. Internal porosities which are caused by air entrapments during the filling process were predicted and also the results of three models were compared with the modifications of the gate system and overflows. Internal porosities which are occurred during the solidification process are predicted with the solidification analysis. And also the results of the modified gate system are compared.

• Composites Research
• /
• v.24 no.4
• /
• pp.41-47
• /
• 2011

This paper deals with anisotropic property and structural analysis for short fiber reinforced plastic composites manufactured by the injection molding process. The common approach for modeling this type of material is the consideration of the material as homogenous and isotropic. However, the common isotropy approach often results in unexpected failure. To overcome this, new structure analysis methodology was developed in order to consider fiber orientation effect using injection mold flow analysis and Halpin-Tsai equations for unidirectional composites and taking an orientation average. The numerical predictions are compared to experimental data for tensile specimen. The predicted mechanical properties agree well with experimental data for fiber orientation and weld line effect. The analysis system was also applied to an automobile part. The proposed anisotropic model predicted different mechanical properties by position of the part and different mechanical performance of the part was changed according to injection gate position.

• Journal of the Korean Society for Precision Engineering
• /
• v.29 no.6
• /
• pp.648-653
• /
• 2012

Cavity pressure, an important factor in injection molding process, should be minimized to enhance injection molding quality. In this study, we decided the locations of valve gates to minimize the maximum cavity pressure. To solve this problem, we integrated MAPS-3D (Mold Analysis and Plastic Solution-3Dimension), a commercial injection molding analysis CAE tool, using the file parsing method of PIAnO (Process Integration, Automation and Optimization) as a commercial process integration and design optimization tool. In order to reduce the computational time for obtaining the optimal design solution, we performed an approximate optimization using a meta-model that replaced expensive computer simulations. To generate the meta-model, computer simulations were performed at the design points selected using the optimal Latin hypercube design as an experimental design. Then, we used micro genetic algorithm equipped in PIAnO to obtain the optimal design solution. Using the proposed design approach, the maximum cavity pressure was reduced by 17.3% compared to the initial one, which clearly showed the validity of the proposed design approach.

• Polymer(Korea)
• /
• v.33 no.3
• /
• pp.203-206
• /
• 2009

Polyaniline Emeraldine salt (PANI-salt) prepared by the common chemical oxidative polymerization caused the corrosion of the metallic injection mold by protonic acid such as HCl which used as a dopant. PANI-salt, polyaniline doped with dodecylbenzenesulfonic acid (DBSA), was obtained by the emulsion polymerization in nonpolar organic solvent, toluene. In this study DBSA was used as a dopant along with a surfactant. PANI-salt and high impact polystyrene (HIPS) have a good solubility in toluene. Blends with different ratio of PANI and HIPS were prepared through a solution-cast blending. The structure of PANI-salt was characterized by FT-IR and UV-Vis. The morphology, thermal, and electrical properties for PANI-HIPS blends were investigated. Injection molded under $103^{\circ}C$, 120 psi, PANI-HIPS showed the highest electrical conductivity ($6.02{\times}10^{-5}\;S/cm$) after blending PANI (50 mL) and HIPS (1 g).

• Journal of Practical Engineering Education
• /
• v.8 no.2
• /
• pp.121-128
• /
• 2016

In injection molding process, the appearance quality issue occurs in most injection molded article. One of thermal designs for the mold was performed by increasing the cavity wall temperature with being as uniform as possible in any position. On the basis of the practical evaluation, the cavity wall temperature and finishing machined cavity surface under the optimum processing conditions are the most significant factors to avoid the appearance issue on the plastic part for a good cosmetic quality. Also, the wrong choice of gate type and location can have a considerable effect on the quality of a molded part and it's so important to keep the correct runner balance from each cavity. We've proposed the education training model of the practical tool technology course for the field oriented education to improve practical tool technology ability and optimized tooling design for injection molding quality which can be performed at the workplace substantially.

• Journal of the Microelectronics and Packaging Society
• /
• v.30 no.2
• /
• pp.1-12
• /
• 2023

In the current era of the global mobile smart device revolution, electronic devices are required in all spaces that people interact with. The establishment of the internet of things (IoT) among smart devices has been recognized as a crucial objective to advance towards creating a comfortable and sustainable future society. In-mold electronic (IME) processes have gained significant industrial significance due to their ability to utilize conventional high-volume methods, which involve printing functional inks on 2D substrates, thermoforming them into 3D shapes, and injection-molded, manufacturing low-cost, lightweight, and functional components or devices. In this article, we provide an overview of IME and its latest advances in application. We review biomimetic nanomaterials for constructing self-supporting biosensor electronic materials on the body, energy storage devices, self-powered devices, and bio-monitoring technology from the perspective of in-mold electronic devices. We anticipate that IME device technology will play a critical role in establishing a human-machine interface (HMI) by converging with the rapidly growing flexible printed electronics technology, which is an integral component of the fourth industrial revolution.

• Proceedings of the Korean Society of Precision Engineering Conference
• /
• 2005.06a
• /
• pp.1206-1209
• /
• 2005

In recent, injection molding process for features in sub-micron scale is under active development as patterning nano-scale features, which can provide the master or stamp for molding, and becomes available around the world. Injection molding has been one of the most efficient processes for mass production of the plastic product, and this process is already applied to nano-technology products successfully such as optical storage media like DVD or BD which is a large area plastic thin substrate with nano-scale features on its surface. Bio chip for like DNA sequencing may be another application of this plastic substrate. The DNA can be sequenced using order of 100 nm pore structure when making the DNA flow through the pore structure. Agarose gel and silicon based chip have been used to sequence the DNA, but injection molded plastic chip may have benefit in terms of cost. This plastic DNA sequencing chip has plenty of pillars in order of 100 nm in diameter on the substrate. When the usual features in case of DVD or BD have very low aspect ratio, even less than 0.5, but the DNA chip will have relatively high aspect ratio of about 2. It is not easy to injection mold the large area thin substrate with sub-micron features on its surface due to the characteristics of the molding process and it becomes much more difficult when the aspect ratio of the features becomes high. We investigated the effect of the molding parameters for injection molding with high aspect ratio nano-scale features and injection molded some plastic DNA sequencing chips. We also fabricated PR masters and Ni stamps of the DNA chip to be used for molding

• Journal of the Korea Academia-Industrial cooperation Society
• /
• v.17 no.10
• /
• pp.499-508
• /
• 2016

Injection molding is a method for manufacturing many products, wherein a plasticized resin is injected into a mold at high pressure and hardened. According to the method, the product can be manufactured into various forms, and the mass production of up to tens of thousands of products is possible. The purpose of this study was to determine the process conditions for manufacturing a door latch for automobiles, through an analysis of the injection molding method. To calculate an appropriate injection flow for injection molding, a primary analysis for comparing the injection time, pressure, flow pattern, consolidation range, shear stress, shear rate, and weld line, as well as a secondary analysis for determining the conditions for stabilizing the molding temperature, holding pressure, and cooling process, were conducted. The characteristics of injection molding, and their influence on the product quality are discussed. No weld line and pores were observed on the products that had been manufactured based on the process conditions determined above. In addition, there were no flaws regarding the deformation compared to the prototype. Therefore, the manufacture of a product under the conditions determined in this study can reduce the defect rate compared to the existing production, and the process is also more competitive due to reduced production time.

• Polymer(Korea)
• /
• v.36 no.6
• /
• pp.685-692
• /
• 2012

Injection molding operation consists of phases of filling, packing, and cooling. The highest cavity pressure is involved in the packing phase among the operation phases. Thus the cavity pressure largely depends upon velocity to pressure (v/p) switchover timing and magnitude of packing pressure. Developed cavity pressure is directly related to stress concentration in the cavity of mold and it may cause a crack in the mold. Consequently control of cavity pressure is considered very important. In this study, cavity pressure was analyzed in terms of v/p switchover timing and packing pressure through computer simulation and experiment. Cavity pressure was increased as the v/p switchover timing was delayed. Residual pressure after cooling phase was observed when the v/p switchover timing was late, which was due to increased pressurizing time for long filling phase. Cavity pressure was increased proportionally with the packing pressure. Residual pressure after cooling phase was also observed, and it was increased with increasing packing pressure. High cavity pressure and residual pressure have been observed at late v/p switchover and high packing pressure. Compared with simulation and experimental results, the profiles of pressures were very similar however simulation could not predict residual pressure. Packing condition was important for the control of cavity pressure and the optimum condition could be set up using CAE analysis.