• Title/Summary/Keyword: molding stability

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A study on the Molding Stability of Hydro-mechanical High Speed Injection Molding for Thin-Walled(0.3mm) LGP (초박형(0.3t) 도광판 적용을 위한 유압식 고속사출성형의 성형 안정성 연구)

  • Kim, J.S.;Oh, J.G.;Jeong, C.;An, H.J.;Hwang, C.J.;Kim, J.D.;Yoon, K.H.
    • Proceedings of the Korean Society for Technology of Plasticity Conference
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    • pp.422-425
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    • 2008
  • Recently, electronic products and related parts are required to have thin thickness because of small form factor. To go with the trend, LGP(light guide plate) of LCD BLU(Liquid Crystal Display Back light unit: It is one of kernel parts of LCD) for cell phone has the thickness of 0.3 mm and the battery case of cell phone has 0.25 mm. Accordingly, high speed injection molding is required to make products which have thin thickness. High speed injection molding means that the resin is injected into the cavity at higher than normal speed avoiding short shot. In the case of hydro-mechanical high speed injection machine, it requires the design for hydraulic unit to make high injection speed and the design for control unit to control hydraulic unit. In the present paper, we concentrated on the molding stability of hydro-mechanical high speed injection machine to make an LGP of 0.3 mm thickness.

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Molding Stability of Hydro-Mechanical High Speed Injection Molding for Thin-Wall(0.3mm) LGP (박판(0.3mm) 도광판 성형을 위한 유압식 고속사출성형의 성형 안정성 연구)

  • Hwang, C.J.;Kim, J.S.;Oh, J.G.;Jeong, C.;An, H.J.;Heo, Y.M.;Kim, J.D.;Yoon, K.H.
    • Transactions of Materials Processing
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    • v.17 no.8
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    • pp.657-661
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    • 2008
  • Recently, products of electronic industry and related parts are required to have the thickness thinner and thinner to reduce the part weight. To go with this trend, LGP(light guide plate) of LCD-BLU(Liquid Crystal Display-Back Light Unit: It is one of kernel parts of LCD) for cell phone has the thickness of ${\sim}0.3mm$ and the battery case of cell phone has ${\sim}0.25mm$. Accordingly, high speed injection molding is required to mold products which have thinner parts. To achieve high speed injection and proper control of hydraulic unit, various design was applied to conventional injection unit. In the present paper, we concentrated on the molding stability of hydro-mechanical high speed injection machine to make an LGP of 0.3mm thickness.

Development of Polymeric Layer for Enhancing The Adhesion of Nano-devices Fabricated by The Nanotransfer Molding Method

  • Lee, Gi-Seok;Seong, Myeong-Mo
    • Proceedings of the Korean Vacuum Society Conference
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    • pp.634-634
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    • 2013
  • Transfer molding methods have a problem that weak adhesion between nanostructures and substrates. It is important to make various nano scale applications, also the stability of nanostructure on substrate is related with device performance. We studied an effect of poly 4-vinylphenol (PVP) as the polymeric adhesion layer between organic nanowires and a Si substrate when the nanowires are transferred by liquid-bridge-mediated nanotransfer molding method (LB-nTM). Their structural stability was examined by optical microscopy, scanning electron microscopy as multiple transfer molding and washing process. Field-effect transistors were fabricated with organic semiconductor nanowires on a polymeric adhesion layer and their electrical properties showed no significant difference as the one without the adhesion layer. As a result, adhesion layer can be used in the washing process and making multi-layer nano-scale patterns.

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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 the Injection Molded Ball Seat for Automobile Suspension (자동차 서스펜션용 볼 시트 사출성형품 개발)

  • Ye, Sang-Don;Min, Byeong-Hyeon
    • Journal of the Korean Society of Manufacturing Process Engineers
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    • v.10 no.4
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    • pp.50-56
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    • 2011
  • Injection molding process is one of the popular manufacturing methods to produce plastic parts with high efficiency and low cost. Ball seat for automobile suspension is made by an injection molding process as a part to support pivot function of ball joint consisted of ball stud and housing. It is necessary for a ball seat to have a dimensional stability in the three dimensional inner area to be contacted with ball stud. In this paper, the dimensional stability of inner surface is indirectly analyzed by checking the difference of inner diameter around the circumferential direction and the thickness variation at the top part of ball seat. Measurement was performed by using the coordinate measuring machine and the fixture to hold ball seat. Optimization of injection molding processes such as injection time, cooling time and temperatures of cylinder barrel was derived to reduce the difference of inner diameter and the thickness variation at the top part of ball seat based on the Taguchi method.

A study on a structural analysis of the injection mold for the plastic subminiature barrel (모바일용 플라스틱 경통 금형의 구조해석에 관한 연구)

  • Chang, Sung-Ho;Heo, Young-Moo;Shin, Gwang-Ho
    • Journal of the Korea Society of Die & Mold Engineering
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    • v.2 no.3
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    • pp.10-15
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    • 2008
  • Recently, mobile-phone with camera module has an absolute majority in the released mobile-phones. For this trend, High precision of the plastic subminiature barrel which is the core part is needed significantly because the camera module of mobile-phone must have high performance. Therefore, Structural stability of the injection mold for plastic subminiature barrel has to be guaranteed. In this paper, structural analysis of injection mold for plastic subminiature barrel is performed. Finally, the deformation trend and stability of injection mold core are analyzed.

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A Study on the Stability Control of Injection-molded Product Weight using Artificial Neural Network (인공신경망을 이용한 사출성형품의 무게 안정성 제어에 대한 연구)

  • Lee, Jun-Han;Kim, Jong-Sun
    • Journal of the Korean Society of Industry Convergence
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    • v.23 no.5
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    • pp.773-787
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    • 2020
  • In the injection molding process, the controlling stability of products quality is a very important factor in terms of productivity. Even when the optimum process conditions for the desired product quality are applied, uncontrollable external factors such as ambient temperature and humidity cause inevitable changes in the state of the melt resin, mold temperature. etc. Therefore, it is very difficult to maintain prodcut quality. In this study, a system that learns the correlation between process variables and product weight through artificial neural networks and predicts process conditions for the target weight was established. Then, when a disturbance occurs in the injection molding process and fluctuations in the weight of the product occur, the stability control of the product quality was performed by ANN predicting a new process condition for the change of weight. In order to artificially generate disturbance in the injection molding process, controllable factors were selected and changed among factors not learned in the ANN model. Initially, injection molding was performed with a polypropylene having a melt flow index of 10 g/10min, and then the resin was replaced with a polypropylene having a melt floiw index of 33 g/10min to apply disturbance. As a result, when the disturbance occurred, the deviation of the weight was -0.57 g, resulting in an error of -1.37%. Using the control method proposed in the study, through a total of 11 control processes, 41.57 g with an error of 0.00% in the range of 0.5% deviation of the target weight was measured, and the weight was stably maintained with 0.15±0.07% error afterwards.

Simulation of injection-compression molding for thin and large battery housing

  • Kwon, Young Il;Lim, Eunju;Song, Young Seok
    • Current Applied Physics
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    • v.18 no.11
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    • pp.1451-1457
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    • 2018
  • Injection compression molding (ICM) is an advantageous processing method for producing thin and large polymeric parts in a robust manner. In the current study, we employed the ICM process for an energy-related application, i.e., thin and large polymeric battery case. A mold for manufacturing the battery case was fabricated using injection molding. The filling behavior of molten polymer in the mold cavity was investigated experimentally. To provide an in-depth understanding of the ICM process, ICM and normal injection molding processes were compared numerically. It was found that the ICM had a relatively low filling pressure, which resulted in reduced shrinkage and warpage of the final products. Effect of the parting line gap on the ICM characteristics, such as filling pressure, clamping force, filling time, volumetric shrinkage, and warpage, was analyzed via numerical simulation. The smaller gap in the ICM parting line led to the better dimensional stability in the finished product. The ICM sample using a 0.1 mm gap showed a 76% reduction in the dimensional deflection compared with the normal injection molded part.

Powder Injection Mold Design for Dental Scaler (Dental Scaler 분말사출용 금형설계)

  • Park H. P.;Ko Y. B.;Chung S. T.;Rhee B. O.;Hwang C. J.
    • Proceedings of the Korean Society for Technology of Plasticity Conference
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    • pp.270-274
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    • 2005
  • The capability of net shaping for complex 3-D geometry, powder injection molding(PIM) is widely used for parts in the field of automotives, electronics and medical industry. Powder injection mold design for dental scaler tip, a component of medical appliance, was presented. In comparison with conventional machining process, powder injection molding has many advantages, specially in price and dimensional stability, for molding dental scaler tip. Product design and mold design for dental scaler tip was presented. Short shot experiment with scaler tip PIM mold and several defect (flash etc.) during injection molding process was discussed.

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Development of Powder Injection Mold for Dental Scaler Tip Using Stainless Series Powder (스테인레스계열(17-4PH, 316L, 440C) 분말을 이용한 Dental Scaler Tip 분말사출금형 개발)

  • Ko, Y.B.;Kim, J.S.;Hwang, C.J.
    • Transactions of Materials Processing
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    • v.16 no.1
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    • pp.61-66
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    • 2007
  • Powder injection molding(PIM) is widely used for many parts in the field of automotives, electronics and medical industries, due to the capability of net shaping for complex 3-D geometry. Powder injection mold design for the dental scaler tip, a component of medical appliance, was presented. In comparison with conventional machining process, powder injection molding has many advantages, specially in price and dimensional stability, for molding dental scaler tip which has complex geometry. Both product design and mold design for dental scaler tip were presented. A PIM feedstock was made of stainless series(17-4PH, 316L, 440C) powder and a wax based binder. The 'rapid mold' concept was applied to manufacture the various forms and materials of dental scaler tip including vibration characteristics.