• Title/Summary/Keyword: Injection Molding

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A Study on the Effects of Filling and Packing Phases on Injection Molding Process (충전과 보압과정이 사출성형공정에 미치는 영향에 관한 연구)

  • 김현필;김용조
    • Transactions of the Korean Society of Machine Tool Engineers
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    • v.11 no.4
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    • pp.44-53
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    • 2002
  • Injection molding process factors such as molding temperature, injection pressure, flow rate and flow velocity, must be controlled properly in filling and packing phases in the injection molding process. In this study, effects of these factors on the injection molding were investigated through the flow analysis for the filling and packing phases. Molding troubles like flow mark weld line, sink ma가 short shot and warpage car be caused by these injection molding process factors. Among them the short shot was caused by the fact that the packing pressure could not reach properly to the filling end part in the packing phase and hence the flow rate could not be supplied to the full. In addition as the flow rate for the volumetric shrinkage during the f개zen phase could not be supplied Properly by the packing pressure, the short shot appeared. Here, the volumetric shrinkage reduced with increasing the packing pressure and also the warpage of molded part increased with increasing the packing Pressure.

A Study on Implementation of Al-Inserted Plastic Injection Molding Process for Automobile Interior-Parts (자동차부품용 알루미늄인서트 사출성형공정 구현에 관한 연구)

  • Lho, Tae-Jung;Kim, Kyung-Soo
    • Journal of the Korean Society for Precision Engineering
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    • v.25 no.5
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    • pp.43-51
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    • 2008
  • Generally a plastic injection molding is a manufacturing process used to produce the various parts of complicated shape at low cost. The objective of this study is to implement a new plastic injection molding process with inserted Aluminum sheet, which is highly durable, light and luminous. Moldflow analysis and simulation of plastic injection molding process with inserted Aluminum sheet were carried out in order to predict optimal molding operation conditions. The experimental results in the Al-inserted plastic injection molding process were compared with the simulation results by Moldflow. Durability and reliability test results for trial products were satisfied to adopt the Al-inserted plastic injection molding process developed as manufacturing of automobile interior parts.

Determination of Molding Conditions of Double-Shot Injection Mold for the Computer Mouse via Three-Dimensional Injection Molding Analysis (3 차원 사출성형 해석을 통한 컴퓨터 마우스 제작용 이중사출성형 금형의 공정조건 결정)

  • Ahn, Dong-Gyu;Park, Min-Woo;Park, Jeong-Woo;Kim, Hyung-Su
    • Transactions of the Korean Society of Mechanical Engineers A
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    • v.35 no.12
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    • pp.1619-1625
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    • 2011
  • The objective of this study determine the molding conditions of a double-shot injection mold for fabricating a computer mouse using different materials, by performing three-dimensional injection molding analysis. In order to select the optical injection molding conditions, the effects of the injection time, the maximum injection pressure, the effect of packing time on the injection molding characteristics, and the product qualities were quantitatively examined. From the results of the injection molding analysis, the optimal injection molding conditions of the double-shot injection mold, which leads the molded product to the minimized shrinkage and deflection, were estimated. The results of the injection molding experiments, showed that an appropriate computer mouse can be fabricated using different materials when the identified optimal injection molding conditions are adopted.

The Effect of Various Molding Methods for Precision Optical Products Using Birefringence Analysis (정밀 광학부품의 복굴절 분석을 통한 각종 성형법의 영향에 관한 연구)

  • Min, I.K.;Cho, S.W.;Yoon, K.H.
    • Transactions of Materials Processing
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    • v.22 no.1
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    • pp.48-53
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    • 2013
  • As the adoption of injection molding technology increases, injected-molded optical products require higher dimensional accuracy and optical stability than ever before. In the present study, four kinds of molding methods, i.e., conventional injection molding (CIM), injection/compression molding (ICM), rapid heat and cooling the mold(RHCM) and rapid injection/compression molding (RICM) were selected in order to investigate the optical anisotropy of a 7 inch Light Guide Plate(LGP) by examining the gap-wise distribution of birefringence and the extinction angle. The results indicate that the compression process can decrease flow-induced birefringence over the whole region and that rapid heating can decrease the birefringence level better than conventional molding. In addition, for the combination of compression and rapid heating a reversal flow was detected from the distribution of the extinction angle near the gate.

Development of an Expert System for Multi-component Injection Molding (다재 사출성형 전문가 시스템 개발)

  • 강신일
    • Proceedings of the Korean Society for Technology of Plasticity Conference
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    • 1999.03b
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    • pp.213-217
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    • 1999
  • An expert system is developed for rational and efficient design of multi-component injection molding which is a fairly new manufacturing technique to produce plastic parts by injecting two or more materials sequentially using multiple injection units in a single machine into a single rotary mold. The knowledge base used in the present design system is primarily composed of two parts ; knowledge from domain expert and knowledge from CAE analysis. The present expert system has hour main modules ; general design guidelines for injection molding specific guidelines for multi-component injection molding redesign guidelines from the result of the CAE analysis and finally troubleshooting for multi-component injection molding. To show the validity of the present design methodology two shop floor design problems were tested ; design and fabrication of timing belt cover and power window's assist knob by using multi-component injection molding.

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A Study on Cycle Time and Power Saving Effect of a Hydraulic Hybrid Injection Molding Machine using a Servo Motor (서보모터를 이용한 유압 하이브리드식 사출성형기의 공정시간 및 절전효과에 관한 연구)

  • Yun, Hongsik;Kim, Sungdong
    • Journal of Drive and Control
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    • v.17 no.3
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    • pp.15-25
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    • 2020
  • The cycle time and power saving effect of a hydraulic hybrid injection molding machine using a servo motor are considered in this paper. In order to verify control characteristics, such as pressure and speed, experiments were performed with the hydraulic hybrid injection molding machine, clamping force of 110 ton. The power consumption and production cycle time of a conventional hydraulic injection molding machine were measured to compare its performances with the hydraulic hybrid injection molding machine. An injection molding machine with a clamping force of 1300 ton was used as the conventional machine, the hybrid machine was implemented by replacing its induction motors with servo motors. In the remodeled hybrid machine, experiments were performed to investigate how the displacement of the mold clamping pump affects the power consumption and production cycle time. The results showed that the production cycle time of the hybrid injection molding is similar to a conventional hydraulic injection molding machine but with a significant energy saving of about 40%.

Development of a Gas Assisted Injection Molding Process for Exterior Display Panels (디스플레이용 외장패널의 가스사출공정 개발)

  • Choi, D.S.;Kim, H.S.
    • Transactions of Materials Processing
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    • v.21 no.1
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    • pp.36-41
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    • 2012
  • Gas Assisted Injection Molding is a relatively new low-pressure injection molding technique that provides benefits such as reduced part warpage, excellent surface quality without shrink marks, greater design flexibility, etc. In the gas assisted injection molding process, the injected pressurized nitrogen gas flows through designed gas channels and forms hollow sections within the part. However, due to the characteristics of the gas, the design of the gas channels which are the paths for the injected gas is important in order to avoid defects such as gas blowout, fingering, etc. Therefore, in this study, the gas channel design for gas assisted injection molding of exterior display panels was conducted by examining the results of three CAE analyses. The designed gas channel was verified by conducting tryouts using a 450 ton injection molding machine with 3-stage pressure controlled gas kit. In addition, the hollow shapes which were formed by the gas with the installed gas channels were examined by examining the cross sections of the prototypes that were produced. As a result, it was found that exterior display panels can be produced without any defect by applying the gas assisted injection molding technique.

Improvement of Flow Characteristics for Thin-Wall Injection Molding by Rapid Beating (급속 가열에 의한 박육 사출성형의 유동특성 개선)

  • Kim, Byung;Park, Keun
    • Proceedings of the Korean Society for Technology of Plasticity Conference
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    • 2005.09a
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    • pp.9-12
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    • 2005
  • The rapid thermal response (RTR) molding is a novel process developed to raise the temperature of mold surface rapidly to the polymer melt temperature prior to the injection stage and then cool rapidly to the ejection temperature. The resulting filling process is achieved inside a hot mold cavity by prohibiting formation of frozen layer so as to enable thin wall injection molding without filing difficulty. The present work covers flow simulation of thin wall injection molding using the RTR molding process. In order to take into account the effects of thermal boundary conditions of the RTR mold, coupled analysis with transient heat transfer simulation is suggested and compared with conventional isothermal analysis. The proposed coupled simulation approach based on solid elements provides reliable thin wall flow estimation fur both the conventional molding and the RTR molding processes

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An Experimental Study on the Reduction of a Birefringence Distribution in LGP by Injection-Press Molding (형체압축성형을 이용한 도광판의 복굴절 저감효과에 관한 실험적 연구)

  • Min I. K.;Kim J. S.;Ko Y. B.;Park H. P.;Yoon K. H.;Hwang C. J.
    • Proceedings of the Korean Society for Technology of Plasticity Conference
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    • 2005.09a
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    • pp.17-22
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    • 2005
  • The residual birefringence in molded plastic parts can be divided into two kinds of residual birefringence, i.e., the flow induced residual birefringence produced in flowing stages and the thermally induced residual birefringence produced in cooling stage. In this paper, the effect of new injection-press molding process with normal injection mold, i.e. I) injection-compression mode, ii) injection-press mode, on the distribution of birefringence was studied. It was found that the values of the birefringence was reduced at i) low clamping force and ii) longer mold opening length by injection-press molding.

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A Study on Injection Molding Analysis and Validation of Large Injection-Molded Body Using Design of Experiment (실험계획법을 이용한 대형 사출물의 사출성형 해석과 검증에 관한 연구)

  • Lee Hyoung-soo;Lee Hi-Koan;Yang Gyun-eui
    • Proceedings of the Korean Society of Machine Tool Engineers Conference
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    • 2005.05a
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    • pp.109-114
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    • 2005
  • The large injection molded parts technology such as instrument panel, front and rear bumper are presented for a precision molding. Some lead time and cost are required to product these part from design to mass product. Recently, CAE is widely used in product design, mold design and analysis of molding conditions to reduce time and cost. The optimal molding conditions can be obtained by DOE(Design of Experiment). The optimal design applications with CAE and DOE have been used in small molded parts. However, application to the large molded body is not reported. In this paper, optimization of injection molding process is studied for quality control in mass production of automobile bumper. Mold temperature difference is chosen through robust design of injection molding process, the molding process being optimized in term of shrinkage and deflection. The optimal conditions through DOE are validated by using injection molding analysis.

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