• 한국정밀공학회:학술대회논문집
• /
• 한국정밀공학회 2003년도 춘계학술대회 논문집
• /
• pp.1354-1357
• /
• 2003

Mold Analysis is crucial factors in the design of injection molding process. Since the qualify of products depends on filing, shrinkage and etc, the procedure of prediction through analysis in the design of injection molding process is needed. In many cases, this kind of analysis makes it possible to predict pressure pattern which determines the condition of injection molding process. Crystallinity is the factor that determines the shrinkage of products. The studies showed the factors that had been related to the degree of crystallinity, which were mostly Weight Reduction, mold temperature and melt temperature. Therefore, the objective of this study is to see the differences of the degree of crystallinity depending on the positions of foamed plastics. The procedure of this study is as the following. First, Simulate the pressure gradient in mold cavity that can produces specimen by using Moldflow. Secondly, produce specimen and measure the degree or crystallinity of each part of specimen by using XRD. Lastly, identify the sensitivity of conventional plastic and foamed plastic on pressure gradient by comparing the simulation and the results of measurement.

• Design & Manufacturing
• /
• 제11권2호
• /
• pp.9-14
• /
• 2017

The design and manufacturing tehcnology of IC sockets beyond 0.3mm pitch were presented. We compared the developed IC socket with the conventional one especially on the core metal-insulation part. Advanced machining techniques were employed to provide high precision. Our wire electrodischarge machining and high speed machining centers were able to maintain the micro-scale precision. We performed an injection molding analysis using a commercial analysis tool to predict the performance of the developed IC socket. We found that the solidification of the plastic resin and the high level of the clamping force are responsible for the defects such as incomplete filling and short shot. From these results, we modified the IC socket and successfully remove the defects. We were also able to find out that the new design socket needs less maintenance cost.

• 대한기계학회논문집A
• /
• 제21권9호
• /
• pp.1470-1479
• /
• 1997

In this study, the plastic fan with high efficiency and low noise was designed and the capacity of the wind and the wind pressure were analysed and verified by CAE. After designing the metallic mold using the metallic mold design data, and the the metallic mold design was reformed by analysing the process of the material stream and injection filling by CAE. Also the metallic mold cutting data were formed using the metallic mold design data. These cutting data was used to produce the fan electrode by a machining center and then this electrode were used to manufacture the metallic mold by cutting the fan cavity by an electrical spark machine. The purpose of this study is to find out the sub-optimal condition on the productivity and improvement in quality of the plastic fan by integrating a series of this process with a computer.

• Design & Manufacturing
• /
• 제2권2호
• /
• pp.33-37
• /
• 2008

This paper describes the optimization of injection molding conditions to minimize sink marks. Sink marks, which refer to a small depression on the surface opposite a thick wall thickness, are often encounted in injection molded plastic parts. Part geometry, material properties and processing conditions during injection molding can affect the sink mark depth. We designed the runner system which is possible balanced filling to cavities using CAE program and then obtained optimal processing conditions by Taguchi's Robust Design technique. By actual injection molding using optimized mold and molding conditions, it confirmed that sink mark depth decreased zero compared to 1mm level in the conventional mold and process.

• 한국기계가공학회지
• /
• 제19권8호
• /
• pp.50-55
• /
• 2020

This study investigates the injection molding of a plastic rack gear and focuses on deflections in the part. The causes of deflections were found and resolved through a trade-off study by injection molding analysis. Based on a warpage analysis, the fiber orientation was found to be a dominant factor in the occurrence of deflections. Changes in the part design and various injection conditions were analyzed for their effects in reducing deflections. Based on the trade-off study, a new part bottom design, injection time, and melt temperature were recommended. A trial injection was done for the new plastic rack gear, and measurements showed that its flatness surpassed that of the original part and met the specified requirement. The short injection time, low melt temperature, and symmetric similar configuration of the part contributed to the reduction in deflections. Therefore, optimized gate design and injection conditions as well as a new part design were validated through injection molding analysis in this study.

• Design & Manufacturing
• /
• 제14권1호
• /
• pp.30-35
• /
• 2020

Plastic pulleys used for the purpose of power transmission have to very high roundness characteristics. The roundness of plastic pulleys is influenced by many factors. In this study, the effect of molding conditions on the roundness of pulleys was analyzed using a numerical analysis program. To improve the roundness, molding conditions that minimize the amount of deformation of the pulley were studied through an experimental design method. Among the experimental design methods, the Taguchi method was used, and the main molding conditions affecting the deformation of the pulley were the resin temperature and the holding pressure. It was found that the amount of deformation is reduced by about 2.86% when molding with the optimum molding conditions compared to when the optimum molding conditions are not applied.

• 한국정밀공학회:학술대회논문집
• /
• 한국정밀공학회 2004년도 추계학술대회 논문집
• /
• pp.223-226
• /
• 2004

It is net easy to predict the shrinkage rate of a plastic injection mold in its design process. The shrinkage rate should be considered as one of the important performances to produce the reliable products. The shrinkage rate can be determined by suing the CAE tools in the design produces. However, since the analysis can take minutes to hours, the high computational costs of performing the analysis limit their use in design optimization. In this study, the surrogate models based on the RSM is used in lien of the original models, facilitating design optimization.

• 동력기계공학회지
• /
• 제18권3호
• /
• pp.51-58
• /
• 2014

Injection molding simulation provided optimized design results by analyzing quality problems while the product is in assembly or in the process of manufacturing with make automobile plastics. Frequent change of design, change of injection molding, repetition of test injection which was held in the old way can now be stopped. And quality upgrade is expected instead. This report deals with the effect which the position of injection molding automobile console gate and number has on product quality including pressure at end of fill, bulk temperature at end of fill, shear stress of end of fill, residual stress at post filling end, product weld lines and warpage results. Simpoe-Mold simulates the complete manufacturing process of plastic injected parts, from filling to warpage. Simpoe-Mold users, whether they are product designers, mold makers or part manufacturers, can identify early into the design stage potential manufacturing problems, study alternative solutions and directly assess the impact of such part modification, whatever the complexity and geometry of such parts, shell part as plain solid parts.

• Design & Manufacturing
• /
• 제6권1호
• /
• pp.12-17
• /
• 2012

In order to produce high-quality optical components, aspheric lenses have been widely applied in recent years. An aspheric lens consists of aspheric surfaces instead of spherical ones, which causes difficulty in the design process as well as the manufacturing procedure. Although injection molding is widely used to fabricate optical lenses owing to its high productivity, there remains lots of difficulty to determine appropriate mold design factors and injection molding parameters. In the injection molding fields, computer simulation has been effectively applied to analyze processes based on the shell analysis so far. Considering the geometry of optical lenses, a full-3d simulation based on solid elements has been reported as a reliable approach. The present work covers three-dimensional injection molding simulation and relevant deformation analysis of an injection molded plastic lens based on 3d solid elements. Numerical analyses have been applied to the injection molding processes of three aspheric lenses for an image sensing module of a mobile phone. The reliability of the proposed approach has been verified in comparison with the experimental results.

• 한국정밀공학회:학술대회논문집
• /
• 한국정밀공학회 2005년도 추계학술대회 논문집
• /
• pp.657-660
• /
• 2005

It is net easy to predict the shrinkage rate of a plastic injection mold in its design process. The shrinkage rate should be considered as one of the important performances to produce the reliable products. The shrinkage rate can be determined by suing the CAE tools in the design produces. However, since the analysis can take minutes to hours, the high computational costs of performing the analysis limit their use in design optimization. Therefore this study was carried out to presume for mutual relation of analysis condition to get the optimum average shrinkage by regression analysis. The results shown that coefficient of determination of regression equation has a fine reliability over 88.3% and regression equation of average shrinkage is made by regression analysis.