• Design & Manufacturing
• /
• 제9권2호
• /
• pp.20-24
• /
• 2015

Recently, the light guide plate (LGP), a component of the BLU, becomes thinner and larger than ever. In industrial field, specialized injection molding technique is applied to mold the ultra-thin LGP such as a ultra-high speed injection molding. Usually very high melt temperature is used for low viscosity. High injection speed and melt temperature lead to yellowing of LGP. In the present paper a series of injection molding experiment was performed under various injection molding conditions. Yellow index, CIE xy, spectral transmittance of sample were measured using the UV-Visible spectrophotometer. Systematic decrease of spectral transmittance in UV-B range was found as the melt temperature was higher. Yellow index and CIE xy were became higher near the gate location in LGP. From the result of analysis of variance, the main factor to affect for yellow index was mold temperature and that for spectral transmittance(at 315 nm) was melt temperature.

• Design & Manufacturing
• /
• 제17권2호
• /
• pp.62-69
• /
• 2023

In this study, we conducted a study on the optimization of injection molding conditions to minimize deformation of plastic product. The charging management system housing of the vehicle was selected as the research subject. Melting temperature, cooling temperature, packing time, and packing pressure were selected as the main factors expected to affect the deformation of molded products. Each main factor was divided into 5 levels. Optimization of injection molding conditions to minimize deformation was performed using the Taguchi Method. We performed an analysis of variance (ANOVA) to identify significant factors affecting the deformation of plastic product. In order to select injection molding conditions that minimize deformation of plastic products, injection molding analysis was additionally performed for insignificant factors. We then compared the deformation of the molded part before and after optimization. As a result of comparing the injection analysis results of the basic conditions and the injection analysis results of the optimal conditions, it was confirmed that the amount of deformation after optimization was improved by about 10.9%.

• 한국세라믹학회지
• /
• 제30권2호
• /
• pp.131-138
• /
• 1993

The effects of silane coupling agents on the injection molding process were investigated using silicone nitride mixtrues with a binder system containing polypropylene as a major binder (55vol% solid loading). The formation of bonding between silicon nitride powder and coupling agents was confirmed through the analyses of powder surface. The use of coupling agents improved mixing characteristics judged by the torque change during mixing process. the coupling agents also reduced molten viscosity of the mixture considerably, which is a main factor to determine the flow of the mixture. However, the bonding between coupling agents and polymers had a negative effect on the debinding process by retarding the thermal decomposition.

• 한국생산제조학회지
• /
• 제26권1호
• /
• pp.30-35
• /
• 2017

The major parts of a vacuum cleaner are molded. The vacuum cleaner works in multi-load conditions. Therefore, the designer needs to optimize the structure and injection molding conditions simultaneously. Here, the main factor of design is the rib shape and thickness. The greater the rib thickness, the greater the stiffness of the structure. However, it causes an increase in weight. On the other hand, the lower the rib thickness, the greater the increase in the injection pressure. However, the weight will be reduced. Therefore, the designer needs to optimize the rib shape and thickness for structure stiffness and injection molding. In order to solve this problem, we propose an optimization method using D.O.E and a response surface model, which is a multi-objective optimization method using the multi-objective genetic algorithm.

• 한국콘크리트학회:학술대회논문집
• /
• 한국콘크리트학회 2006년도 추계 학술발표회 논문집
• /
• pp.441-444
• /
• 2006

Extrusion molding concrete panel is cured two times, that is the steam curing at atmospheric pressure and a high-pressure steam curing(autoclaving). Steam curing at atmospheric pressure is done before autoclaving and to acquire the proper strength for treat in process. Though this curing is the important factor on the quality of product and the speed in manufacturing process, it was not evaluated properly so far. Because of ignorance about curing, some engineers even think that the dry curing is better than the steam curing. This study is to investigate the properties of specimen according to variation of curing conditions in the coring chamber such as laboratory scale, pilot plant, and commercial plant. As estimating, in case of steam curing at atmospheric pressure to make extrusion molding concrete panel, moisture curing is better than dry curing and the desirable maximum temperature in curing chamber is about $50^{\circ}C$.

• Design & Manufacturing
• /
• 제15권2호
• /
• pp.56-62
• /
• 2021

In this study, design technology of a non-mechanical flow meter using fluidic oscillation generated during the fluid flow in the chamber was investigated. To with respect to design a splitter, which is the most important factor in fluid oscillation, a transient flow simulation analysis was performed for three types of shapes and changes in inlet flow velocity. The oscillation characteristics with respect to the time in each case were compared, and it was confirmed that the SM03 model was the best among the presented models. In addition, the FFT analysis of the fluid oscillation results for the SM03 model was used to obtain a linear correlation between the flow velocity change and the maximum frequency, and a frequency of 20.957 (Hz/m/s) per unit flow velocity was obtained. Finally, injection molding simulation and molding experiment of the chamber with the designed splitter were performed.

• 대한기계학회:학술대회논문집
• /
• 대한기계학회 2001년도 추계학술대회논문집A
• /
• pp.853-858
• /
• 2001

Generally, mixed materials of LDPE, EVA and foaming agent are manufactured by crosslinking foaming or chemical foaming process. Above materials were used in a microcellular foaming injection molding process. Influence of each factor such as injection type, temperature of barrel, rate of mixed materials and contents of foaming agent was estimated by DOE(Design of Experiments). As a result of experiments, injection type and rate of LDPE, EVA have an influence on foaming rate. This data can be used in field of application of LDPE and EVA.

• 대한기계학회논문집A
• /
• 제34권8호
• /
• pp.1097-1103
• /
• 2010

사출성형에서 사출압력은 제품의 특성을 결정하는 주요인자이므로 성형품의 품질 향상을 위해 사출압력은 최소화 되어야 한다. 또한 휨 변형과 웰드라인은 사출성형에서의 대표적인 불량요인으로 사출성형품의 품질 향상을 위해 방지되어야 한다. 본 논문에서는 사출성형품의 품질 향상을 위해 설계 절차를 2 단계로 나눈다. 첫 번째 설계에서는 공정조건을 제어하여 사출압력과 휨 변형을 최소화 하기 위해 직교배열표를 이용한 전산실험을 수행하고 이를 이용하여 근사모델을 생성한 후 최적설계를 수행한다. 두 번째 설계에서는 유동경로 개선을 통한 웰드라인의 발생을 방지하기 위해 해석모델의 두께를 변경하고 웰드라인 발생 유무를 평가한다. 이러한 설계절차를 통해 사출압력과 휨 변형을 최소화하면서 웰드라인을 방지하여 본 논문에서 제안한 설계방법의 유효성을 보이고자 한다.

• 대한기계학회논문집A
• /
• 제25권8호
• /
• pp.1294-1301
• /
• 2001

In order to reduce the time and cost for assembly, automobile speaker grills have been injection molded with door trims or map pockets in one piece recently. However, several defects such as short shots or air traps can easily occur due to the decreased fluidity of the melting polymer according to the excessive heat transfer to the mold. Therefore, it is necessary to optimize the resin feed system and predict possible defects by CAE analysis. However it is not possible to obtain exact analysis results for the speaker grill by using general shell elements since the heat transfer in the thickness direction which is the dominant factor of the filling stage can not be considered. Therefore, there have been several efforts to simulate the injection molding nature of the speaker grill by using shell elements with an effective thickness which is smaller than the actual thickness of the part. Two empirical values have been recommended for the effective thickness in real practice. One is 50∼70% of the thickness of the speaker grill and another is the gap distance between the adjacent holes. In this paper, CAE analyses of a map pocket with a speaker grill were conducted using shell elements with both of these recommended effective thicknesses, and the predicted flow fronts were compared with the findings from injection molding experiments. The commercial code MOLDFLOW was used for injection molding analysis and an 850 ton injection molding machine was used for experiments.

• Korean Chemical Engineering Research
• /
• 제44권2호
• /
• pp.136-148
• /
• 2006

주물공장에서는 주철을 녹여서 다양한 기계부품을 만든다. 다양한 기계부품을 만들기 위해 목형을 주물사에 넣은 후 주입구를 만들어 녹인 주철을 투입한다. 주물공장은 furan 공정을 포함해 많은 공정으로 이루어지며, 이 중 furan 공정은 목형에 주물사를 부어 넣는 공정이다. Furan 공정의 첫 단계는 주물사가 서로 엉겨 붙어 있게 하기 위해 접착성을 가지는 고분자 물질인 furan류를 주물사에 섞게 되고 녹은 주철이 목형으로 들어가는 것이며 고온에 의해 많은 유해 VOC류가 발생하게 된다. 또 공정조업에서 furan용 모래를 목형이 든 주물형틀에 부어 넣게 되고, 이때도 유독가스와 분진이 발생하게 되며 이 분진은 furan 물질을 포함하고 있어 조업자의 건강에 치명적인 요소가 되며, 이로 인해 조업기피현상이 심화되어 인력수급에 문제가 되고 나아가 사업 경영에 큰 걸림돌이 되고 있다. 본 연구는 이러한 조업기피의 원인을 제거하고 쾌적한 조업환경을 제공하기 위해 유해 VOC류와 집진을 동시에 수행할 수 있는 유해 VOC 및 분진 동시제거 시스템을 최적 설계하고 나아가 현장에 적용 설치하였다. 그 결과 설치 후 포름알데히드의 경우 VOC 0 ppm, 분진 $4{\mu}g/m^3$으로 조업환경이 개선되었으며, 조업자들의 조업 기피 요인을 해소하였다. 또한, 우리는 회사의 고용 문제를 해결하고, 작업의 생산성을 향상시킬 수 있었다.