• Proceedings of the KAIS Fall Conference
• /
• 2011.12b
• /
• pp.514-517
• /
• 2011

본 연구에서는 사각형태 화장품 케이스 사출성형 시 발생되었던 수지 미성형 불량을 해결하기 위하여 사출성형해석 기술을 통해 성형품 형상변경 및 사출금형 내 유동 시스템 수정방안 도출을 수행하였다. 대상제품인 사각형태 화장품 케이스는 상측부 케이스로서 케이스 외관에 게이트 및 취출흔적이 남지 않아야 함에 따라 측면부 게이트 적용으로 유동거리가 길어져 미성형 불량이 다수 발생하는 제품이다. 따라서, 수지 유동성 향상과 더불어 효율적인 보압전달을 통하여 수지 충전 및 변형발생 저감을 위하여 성형품 형상변화 및 유동시스템 변화에 따른 사출성형해석을 수행하고 결과를 고찰하였다. 이로써 최종적으로 수지 미충전으로 인한 미성형 불량을 제거하고 성형품 변형을 줄일 수 있는 수지유동시스템 수정방안을 제시하였다.

• Proceedings of the Korean Society of Precision Engineering Conference
• /
• 2007.06a
• /
• pp.445-446
• /
• 2007

• Proceedings of the Korean Society of Precision Engineering Conference
• /
• 2011.06a
• /
• pp.1349-1350
• /
• 2011

• Transactions of the Korean Society of Mechanical Engineers A
• /
• v.39 no.10
• /
• pp.1021-1028
• /
• 2015

Subminiature lenses are currently widely used in mobile phone cameras and are usually produced by injection molding. The lens molding process has the unique feature of a runner volume that is much larger than the part volume, and this feature should be considered when determining the mold design and molding conditions. In this study, a shell-type runner was proposed as an alternative to the conventional cylindrical runner used for lens molding. An injection molding simulation was performed by applying the proposed shell runner, and the simulation results were compared with those from the cylindrical runner case. It was found that the shell runner could considerably reduce the runner cooling time with only a slight increase in the injection pressure. The effect of the runner thickness was then investigated numerically in terms of the mold filling and cooling characteristics, from which an optimal runner thickness could be determined.

• Journal of the Korea Academia-Industrial cooperation Society
• /
• v.16 no.1
• /
• pp.35-42
• /
• 2015

Injection molding is a high efficient manufacturing technology for producing plastic parts. On the other hand, the warpage of molded plastic parts is an ubiquitous problem in the injection molding process. The main objective of this study was to minimize the amount of warpage occurring in the injection molding process of a hopper of ATDPS made of crystalline polymer (PP) instead of amorphous polymer (ABS). The moldflow CAE simulation was conducted for the molding process of the hopper to clarify the injection moldability, shear rate, shear stress, warpage by changing the gate shape and the number of ribs installed on the top of the hopper flange. The wide gate shape of runner system and multiple rib installation were found to be useful for minimizing the warpage of the hopper. The validity of the CAE simulations was supported by the injection molding experiment for the optimized design case.

• Journal of the Korea Academia-Industrial cooperation Society
• /
• v.11 no.4
• /
• pp.1361-1366
• /
• 2010

This research aims to develop polymer composites which can be used for PEMFC separators by injection molding process. Considering the moldability and stiffness, we used PPS(Poly(phenylene sulfide)) and PP(Polypropylene) as base resin. In order to improve electrical conductivity and physical properties, we chose glass fiber, carbon fiber, carbon black, and both expanded graphite and synthetic graphite. The 3 type composites are prepared for injection molding of PEMFC separators. and CAE(Computer Aided Engineering) analysis was conducted to optimize injection processing parameters(injection pressure, heat time, mold temperature etc.). We did successfully fabricate the separators by injection molding, and measure the electrical conductivity of the samples by using four point probe device. Conclusively, PP/SG/CB composite showed better both electrical conductivity and moldability than the others.

• Korean Chemical Engineering Research
• /
• v.50 no.2
• /
• pp.264-269
• /
• 2012

Die slide injection marvelously reduces the cost and time in processing plastic products because they can simplify the conventional process through eliminating additional process. However, this process must resolve some defects like whitening, resin infiltration, blowhole, resin overflow, etc. In this study, the process parameters of the injection molding are optimized by using the finite element method and Taguchi method. The injection molding analysis is simulated by employing the Moldflow insight 2010 code and the 2nd injection is by adopting the Multi-stage injection code. The process parameters are optimized by using the $L_{16}$ orthogonal array and smaller-the-better characteristics of the Taguchi method that was used to produce an airtight container (coolant reservoir tank) from polypropylene (PP) plastic material.rodanwhile, the optimum values are confirmed to be similar in 95% confidence and 5% significance level through analysis of variance (ANOVA). rooreover, new products and old products were compared by mdasuring the dimensional accuracy, resulting in the improvement of dimensional stability more than 5%.

• Journal of the Korean Society of Propulsion Engineers
• /
• v.21 no.1
• /
• pp.72-83
• /
• 2017

A thermo-fluid dynamic analysis was performed through the numerical simulation of a missile canister. Calculation was made in a fixed analytical volume and fully evaporated water was used as a coolant. To analyze the interaction among the hot gas, coolant, and mixture flow, Realizable $k-{\varepsilon}$ turbulence and VOF(Volume Of Fluid) model were chosen and parametric study was performed with the change of coolant flow rate. It could be found that the pressure on the canister top nonlinearly increased with the increase of coolant flow rate. Temperature and coolant distribution were closely related to the flow behavior in canister. Temperature on the canister bottom indicated a decrease being proportional to coolant flow rate in early times but after a specific time, the temperature increased with the tendency being reversed. In addition, the early part of temperature showed a fluctuating phenomenon because of the overall circulatory flow of mixture gas.

• 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.

• Proceedings of the KAIS Fall Conference
• /
• 2011.12b
• /
• pp.413-416
• /
• 2011

Flip top cap은 경량성, 가공성, 내식성 우수하여 최근에 생활 용기 뚜껑으로 많이 활용되고 있다. Flip top cap은 사출성형에 의해 제작 되며 사출성형 과정에서 힌지부분에 웰드라인(Weldline)이 형성되어 기계적 강도가 떨어지게 된다. Flip top cap은 생활용기에 사용되며 실제생활에서 많은 작동을 요구하기 때문에 힌지부분의 웰드라인은 제품불량에 큰 원인이 된다. 또한 Flip top cap은 생산성을 높이기 위해 멀티캐비티(Multi-cavity) 사출방식을 선호한다. 멀티캐비티 방식은 높은 사출압력을 요구하기 때문에 사출품의 불량과 사출기에 많은 부하가 예상된다. 본 연구에서는 게이트 위치를 조정함으로써 사출품 힌지부분에서 발생할 수 있는 웰드라인을 품질에 영향이 없는 곳으로 이동시키고 최적의 사출 압력을 찾기 위한 유동해석을 통해 최적의 사출조건을 도출함으로써 Flip top cap의 기계적 품질과 제품생산성 향상을 위한 연구가 수행되었다.