컴퓨터 해석을 통한 사출압축성형의 성형특성에 관한 연구

천용호 ( Y. H. Chun ),안형광 ( H. G. An ),류민영 ( M. Y. Lyu ) 한국고무학회 2012 엘라스토머 및 콤포지트 Vol.47 No.4

사출성형은 고분자성형법 중에서 가장 광범위하게 활용되고 있다. 사출성형은 전형적인 사출성형 외에 가스사출, 물사출, 그리고 사출압축성형 등과 같이 특수한 사출성형방법들이 쓰인다. 사출압축성형은 사출과 압축공정이 합쳐진 것으로 균일한 물성 및 성형의 정밀도를 향상시키기 위하여 사용된다. 또한 사출압축은 잔류응력을 줄이는데도 효과적으로 사용되고 있다. 본 연구에서는 성형품의 형상에 따라 다양하게 나타나는 사출압축성형의 특성에 대해서 컴퓨터 해석을 통해 분석하였다. 성형품에 벽이 있는 제품은 벽의 두께가 압축의 방향과 직각이므로 압축효과가 작게 나타났다. 사출압축성형을 일반사출성형과 비교하였을 때 수축의 균일성 및 수축량 또는 성형수축률이 작게 나타나서 정밀성형에 유리하게 나타났다. 실험계획법을 통해 실제로 제작되고 있는 렌즈에 대해서 최적 사출압축조건을 구하고 이의 결과를 사출성형의 결과와 비교분석하였다. Injection molding is one of the widely used polymer processing operations. It is being used for not only conventional injection molding but gas injection molding, water injection molding, and injection compression molding. Injection compression molding involves injection and compression operation, and it gives uniform physical property and high dimensional quality of product. In this study, injection compression characteristics for various product shapes have been investigated by computer simulation. Product containing side wall showed not much effective in injection compression molding since wall thickness direction was perpendicular to the compression direction. Uniform and low shrinkage was observed in injection compression molding comparing conventional injection molding. Subsequently injection compression molding can be used for molding precise product. Optimal injection compression molding condition was obtained using design of experiment for plastic lens and the results were compared with conventional injection molding.

Analysis of the Physical Quantity Variation in the Cavity and the Quality of the Molded Product According to the Injection Speed in Injection Molding

( Soon Yong Kwon ),( Jung Hwan Cho ),( Hyung Jin Roh ),( Sung Hwan Cho ),( Yoo Jin Lee ),( Min-young Lyu ) 한국고무학회 2017 엘라스토머 및 콤포지트 Vol.52 No.4

Molding conditions can be described as factors that determine the quality of a product obtained from injection molding. Many studies have been performed on the injection molding pressure, injection temperature, packing pressure and other molding conditions related to part quality. However, the most accessible factor among the adjustable molding con-ditions during actual injection is the injection speed. In this study, we simulated the variation of the physical quantity accord-ing to injection speed and performed experiments to understand the effect of injection speed on the actual product. A CAE analysis program (Moldflow) was used to simulate and analyze the results using PC and PBT for two models. In order to compare these results with the experimental results, an actual injection molding was performed for each injection speed, and the correlation between simulation and injection molding, especially for the shrinkage of the molded article, was dis-cussed.

사출성형공정에서 금형에 전달되는 진동 신호 측정을 이용한 성형 단계별 공정시간과 공정특성의 모니터링에 대한 연구

이준한,김종선,Lee, Jun-han,Kim, Jong-Sun 한국금형공학회 2020 한국금형공학회지 Vol.14 No.3

In this study, the vibration signal of the mold was measured and analyzed to monitoring the process time and characteristics during injection molding. A 5 inch light guide plate mold was used to injection molding and the vibration signal was measured by MPU6050 acceleration sensor module attached the surface of fixed mold base. Conditions except for injection speed and packing pressure were set to the same value and the change of the vibration signal of the mold according to injection speed and packing pressure was analyzed. As a result, the vibration signal had a large change at three points: "Injection start", "V/P switchover", and "Packing end". The time difference between "injection start" and "V/P switchover" means the injection time in the injection molding process, and the time difference between "V/P switchover" and "Packing end" means the packing time. When the injection time and packing time obtained from the vibration signal of the mold are compared with the time recorded in the injection molding machine, the error of the injection time was 2.19±0.69% and the error of the packing time was 1.39±0.83%, which was the same level as the actual value. Additionally, the amplitude at the time of "injection start" increased as the injection speed increased. In "V/P switchover", the amplitude tended to be proportional to the pressure difference between the maximum injection pressure and the packing pressure and the amplitude at the "packing end" tended to the pressure difference between the packing pressure and the back pressure. Therefore, based on the result of this study, the injection time and packing time of each cycle can be monitored by measuring the vibration signal of the mold. Also, it was confirmed that the level and trend of process variables such as the injection speed, maximum injection pressure, and packing pressure can be evaluated as the change of the mold vibration during injection molding.

콤팩트 파우더 화장품용 고밀폐 용기 제작을 위한 이중사출 성형해석 고찰

김건희(G. H. Kim),윤길상(G. S. Yoon),이정원(J. W. Lee),손종인(J. I. Sohn),김유진(Y. J. Kim),이중배(J. B. Lee) 한국소성가공학회 2012 한국소성가공학회 학술대회 논문집 Vol.2012 No.10

Recently, in the products through injection molding process, it was manufactured to apply more than two resins according to parts of functionality and aesthetic appreciation and double-injection molding process was for that. Double-injection molding is some kind of technology that two resins was injected in one mold at the same time. Thereby, it is had advantage for productivity. In earlier study, first and second injection molding cycle time was different for each other. Because, each two resins were considered independently in injection molding analysis research that it was drew the conclusions of injection molding process conditions. In this study, the first and second injection molding cycle time was drew conclusions to consider the characteristics of double-injection molding process that has a same cycle time during first and second injection molding. The injection time, packing time and cooling time that were made up the injection molding cycle time, were decided to consider first and second deflection of products, gate part frozen time and whole parts frozen time for each parts.

Modeling and analysis of multi-shot injection molding of Blu-ray objective lens

Min-Wen Wang,Chao-Hsien Chen,Fatahul Arifin,Jian-Jr Lin 대한기계학회 2018 JOURNAL OF MECHANICAL SCIENCE AND TECHNOLOGY Vol.32 No.10

The Blu-ray objective lens is one of the electronic parts that has an important role in data storage in such a way that its production requires a high level of accuracy. One way to produce the Blu-ray objective lens is by means of a micro-injection molding technique. We investigated the effect of insert part in a multi-shot injection molding on the shrinkage after the process of injection. An aspherical shape is made for the insert part of the Blu-ray objective lens, then compared with single-shot injection molding. Zemax software was used to design the Blu-ray objective lens, while Moldex3D software was applied to analyze the flow of material into the mold during the injection process. The Taguchi method was used to determine the best parameters to obtain the minimum shrinkage values of the injection processes of both multi-shot injection and single-shot injection molding techniques. Based on the observations, it is clearly evident that the multi-shot injection molding process has a lower displacement value compared to the single-shot injection molding, namely, 0.0161 mm compared to 0.0550 mm and also the multi-shot injection can save the cooling time 5 seconds faster than single-shot injection molding. So, this can favorably improve the production of the injection process for the material in the form of the micro part.

사출-구조 연성해석을 통한 Glass Fiber 배향성이 충격 파괴에 미치는 영향

김웅(Woong Kim),김종량(JongRyang Kim) 한국자동차공학회 2017 한국 자동차공학회논문집 Vol.25 No.1

The use of engineering plastics in automotive components is increasing with the trend towards improving the car strength and reducing weight. Among the different choices of materials, engineering plastic emerged as the necessary material for achieving lower costs, reduced weight and improved production efficiency. To produce the automotive parts, it is important to predict defect and validation of injection molding prior to design. Injection molding analysis and structural analysis are widely applied as a part of the design process when developing automotive parts. Injection molding analysis, in particular, involves a highly complicated mechanism that requires deep knowledge of polymer properties as well as an analytic approach different from that used for a general isotropic material when the molded material is used as a structural material. This is because the parts made of polymer have pre-stress factors such as intrinsic deformation and residual stress. The most important factors for injection molded plastic products are injection molding condition and cavity design, taking into account ease of molding, mass production and application. Despite optimal injection molding conditions and cavity design, however, glass fiber orientation is critically linked to strength reduction. The application of injection molding and structural coupled analysis provides a low-cost solution for product molding and structural validation, all prior to the actual molding. The purpose of this study involves the validation, pre-study, and solution of defect in injection-molded polymer automotive parts using the simulation software for injection molding and structural coupled analysis. Finally, this thesis provides validation of an injection molding and structural coupled analytic mechanism that can demonstrate the effect of glass fiber orientation on mechanical strength. Design improvement ideas for the injection molded product of PPS (Poly Phenylene Sulfide)+40% glass fiber are also suggested.

Injection molding of a nanostructured plate and measurement of its surface properties

Yoo, Y.E.,Kim, T.H.,Choi, D.S.,Hyun, S.M.,Lee, H.J.,Lee, K.H.,Kim, S.K.,Kim, B.H.,Seo, Y.H.,Lee, H.G.,Lee, J.S. Elsevier 2009 CURRENT APPLIED PHYSICS Vol.9 No.2

This paper highlights recent research on the injection molding of a surface nanostructured substrate with super-hydrophobicity or dry adhesiveness. An anodic aluminum oxidation (AAO) membrane or layer on an Si wafer is used as a molding master for surface nanostructures. The AAO membrane or layer has closely packed nanoholes; depending on the AAO membrane used, the nanoholes have a diameter of around 200nm and a depth that varies from a few hundred nanometers to 60μm. This AAO master is installed directly in the injection molding tool, or the AAO holes are replicated on the nickel stamper by an electroforming process and installed in the injection molding tool. Either a high temperature (>T<SUB>g</SUB> of the molding material) mold or a rapid heating (up to 200<SUP>o</SUP>C) and cooling (<70<SUP>o</SUP>C) mold is used to fill the high aspect ratio nanoholes with thermoplastic melt for the injection molding. These high aspect ratio nanoholes are extremely difficult to fill with melt in a conventional injection molding process. This paper proposes a new simple and efficient rapid heating and cooling method that heats the stamper by means of the electrical resistance of the stamper itself. Depending on the aspect ratio of the structures and the type of master, a chemical etching or mechanical ejecting process is used to release the molded surface nanostructures. With the use of an AAO membrane and a high temperature mold, some polypropylene disks with a nanohairy surface and some polycarbonate plates with a nanopillar on the surface are injection molded at several different mold temperatures for the purpose of studying the replication of the surface nanostructures. In addition, the contact angle of the water and the adhesion force on the molded surfaces are measured to investigate the effect of the surface nanostructures on the hydrophobicity or dry adhesiveness.

CAE analysis for improving dimensional stability of ABS injection molded products

Kanggon Kim(김강곤),Sangho Lee(이상호),Yonghee Lee(이용희) 대한인간공학회 2021 대한인간공학회 학술대회논문집 Vol.2021 No.11

Objective: The cost of making a mold increases significantly as the quality level of the mold increases. In general, the production of molds is done in the direction of maximizing the quality, considering the production cost and the quality of the mold. The purpose of this study is to optimize the dimensions of injection-molded products through CAE analysis focusing on dimensional stability with the NG variables of dimensions. Background: Plastic molded products are produced by considering various variables such as appearance, assembly, and process as well as functional aspects of the product. Inadequate management of the dimensions of the molded product causes poor assembly quality and appearance, resulting in cost. However, studies related to CAE on the dimensions of plastic molded products are lacking. Therefore, as a method to systematically manage dimensional stability, research on the optimization of mold design as well as optimization of injection molding conditions is required. Method: The mold design was optimized by applying CAE molding analysis in the process of manufacturing an automobile interior injection mold for ABS resin. The CAE simulation results were applied to the mold making and injection molding process to produce a prototype and the results were analyzed. Results: Injection molding CAE simulation results were applied to mold manufacturing and injection process conditions, and the results of securing molding quality and dimensional stability were confirmed. Conclusion: A comparative analysis was performed on the physical properties and appearance characteristics of the existing ABS injection product and the ABS injection product to which the injection process conditions of this study were applied. The products to which the results of this study were applied showed better physical properties and appearance characteristics. Application: As a result of this study, dimensional stability will be secured in mold manufacturing, resulting in cost reduction by reducing defects. Furthermore, it is expected that CAE analysis in this study can be used as a useful tool along with the improvement of the productivity of ABS injection products.

사출성형해석을 이용한 수직머시닝센터 ATC 툴 포트의 사출 게이트 위치에 따른 성형성 평가

이여울(Yu-Wool Lee),박철우(Chul-Woo Park),김진록(Jin-Rok Kim),최현진(Hyun-Jin Choi) 한국기계가공학회 2021 한국기계가공학회지 Vol.20 No.12

Injection molding is a manufacturing method of melting the polymer resin and injecting it into a mold to molding it into the desired form. Due to the short molding time and outstanding formability, complex products can be shaped with high precision and it is the most widely used polymer molding method. However, there may be areas that are not filled depending on the location of the injection gate where polymer resin is injected. Formability is determined by deformation and surface precision due to the impact of residual stress after molding. Hence, choosing the location of the injection gate is very important and molding analysis of injection molding is essential to reduce the cost of the mold. This study evaluated the injection formability based on the location of the injection gate of the vertical machining center ATC tool port using injection molding analysis and the results were compared and analyzed. Injection molding analysis was conducted on filling, packing, and deformation according to the location of the gate of the ATC tool port. From each injection gate location, filling time, pressure, and maximum deformation were compared. At gate 2, conditions of molding time and the location of the gate were far superior in production and quality. Gate 2 produced the smallest deformation of 0.779mm with the best quality.

미세패턴 성형을 위한 사출 압축 성형 공정 기술

유영은(Y.-E. Yoo),김태훈(T. H. Kim),김창완(C. W. Kim),제태진(T.J. Je),최두선(D.S. Choi) 한국정밀공학회 2005 한국정밀공학회 학술발표대회 논문집 Vol.2005 No.10월

The injection molding is very effective process for various plastic products due to its high productivity. It is also good for precise products like optical parts. Various thermoplastic materials are also available with this injection molding process. In recent, however, as the overall size of the product increases and micro or nano scale of patterns are applied to the products, we now have some problems such as low fidelity of the replication of the pattern, high molding pressure, or warpage from the in-mold stress. Injection/compression molding is studied to overcome those problems in molding large thin plate with micro pattern array on its surface. An injection compression mold is designed to 3 pieces mold for side gate. We install 4 pressure transducers and 9 thermocouples to measure the melt pressure and surface temperature in the cavity during the process. As a result, the maximum molding pressure for injection compression molding is reduced to 1/3 compared to injection molding and the uniformity of the pressure in the cavity is enhanced by about 15%.