• Title/Summary/Keyword: Injection-Press Molding

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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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Development and mechanical properties of bagasse fiber reinforced composites

  • Cao, Yong;Goda, Koichi;Shibata, Shinichi
    • Advanced Composite Materials
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    • v.16 no.4
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    • pp.283-298
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    • 2007
  • Environment-friendly composites reinforced with bagasse fiber (BF), a kind of natural fiber as the remains from squeezed sugarcane, were fabricated by injection molding and press molding. As appropriate matrices for injection molding and press molding, polypropylene (PP) and polycaprolactone-cornstarch (PCL-C) were selected, as a typical recyclable resin and biodegradable resin, respectively. The mechanical properties of BF/PP composites were investigated in view of fiber mass fraction and injection molding conditions. And the mechanical properties and the biodegradation of BF/PCL composites were also evaluated. In the case of injection molding, the flexural modulus increased with an increase in fiber mass fraction, and the mechanical properties decreased with an increase in cylinder temperature due to the thermal degradation of BF. The optimum conditions increasing the flexural properties and the impact strength were $90^{\circ}C$ mold temperature, 30 s injection interval, and in the range of 165 to $185^{\circ}C$ cylinder temperature. On the other hand, as to BF/PCL-C fully-green composites, both the flexural properties and the impact strength increased with an increase in fiber mass fraction. It is considered that the BF compressed during preparation could result in the enhancement in mechanical properties. The results of the biodegradability test showed the addition of BF caused the acceleration of weight loss, which increased further with increasing fiber content. This reveals that the addition and the quantities of BF could promote the biodegradation of fully-green composites.

An Experimental Study on The Improvement of Pattern Replication and Birefringence in LGP by Adding Compression Effects (압축효과를 가미한 도광판의 전사성과 복굴절 향상에 관한 실험적 연구)

  • Min I. K.;Kim J. S.;Ko Y. B.;Park H. P.;Yoon K. H.;Hwang C. J.
    • Transactions of Materials Processing
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    • v.15 no.1 s.82
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    • pp.27-33
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    • 2006
  • It is necessary to improve the pattern replication and birefringence in LGP(Light guide panel) for better optical performance. In the present paper, the effects of injection-compression and injection-press mode with normal injection mold on the distribution of transcription of pattern and birefringence were studied. It was found that the values of pattern replication was improved and the birefringence was reduced for the cases of low initial clamping force in injection-compression mode and for the cases of longer mold opening length in injection-press mode, repectively.

A Study of Mold Technology for Manufacturing of CFRTP Parts (CFRTP 부품제조를 위한 금형 및 성형 기술에 대한 연구)

  • Jung, Eui-Chul;Kim, Jong-Sun;Son, Jung-Eon;Yoon, Kyung-Hwan;Lee, Sung-Hee
    • Design & Manufacturing
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    • v.11 no.3
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    • pp.25-28
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    • 2017
  • The production of carbon fiber reinforced thermoplastics(CFRTP) parts using an injection/compression molding process that differs from the conventionally used fabrication methods was investigated Before the application of composite molding in the injection/compression molding process, a simple compression molding experiment was performed using a hydraulic press machine to determine the characteristics of resin impregnation and to obtain a basic physical property data for the CFRTP. Based on these results, injection/compression molded specimens were manufactured and an additional insert/over molding process was applied to improve the impregnation rate of the molded specimens. The results demonstrated that the tensile strength of the molded parts using the faster injection/compression process was similar to that of a hydraulic press molded product.

Isothermal Compression Molding for a Polymer Optical Lens (등온압축성형공법을 이용한 폴리머 렌즈 성형)

  • Oh, Byung-Do;Kwon, Hyun-Sung;Kim, Sun-Ok
    • Proceedings of the KSME Conference
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    • 2008.11a
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    • pp.996-999
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    • 2008
  • Aspheric polymer lens fabrication using isothermal compression molding is presented in this paper. Due to increasing definition of an image sensor, higher precision is required by a lens which can be used as a part of an imageforming optical module. Injection molding is a factory standard method for a polymer optical lens. But achievable precision using injection molding has a formidable limitation due to the machining of complex mold structure and melting and cooling down a polymer melt under high pressure condition during forming process. To overcome the precision requirement and limitation using injection molding method, isothermal compression molding is applied to fabrication of a polymer optical lens. The fabrication condition is determined by numerical simulations of temperature distribution and given material properties. Under the found condition, the lens having a high precision can successfully be reproduced and does not show birefringence which results often in optical degradation.

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WC-Co Milling Inserts Manufactured by Powder Injection Molding (분말사출성형에 의한 WC-Co 계 milling insert 제조)

  • 성환진
    • Journal of Powder Materials
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    • v.6 no.1
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    • pp.88-95
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    • 1999
  • The purpose of this study is to investigate the manufacturing feasibility of WC-Co milling inserts via Powder Injection Molding (PIM) process. WC-Co is used in a wide variety of cutting tools due to its high hardness, stiffness, compressive strength and wear resistance properties. WC-Co parts for a high stress application were conventionally produced by the press and sinter method, which were Iimited to 2 dimensional shapes. Manufacturing WC-Co parts for a high stress application by PIM implies that tool efficiency can be highly improved due to increased freedom is design. P30 grade WC powder (WC-Co-TiC-TaC system) was mixed with RIST-5B133 binder and injection molded into milling inserts (Taegu Tech. Model WCMX 06T 308). The mean grain size of the powder was about 0.8$\mu$m. Injection molded specimens were debound by solvent extraction and thermal degradation method at various conditions. The specimens were sintered at 140$0^{\circ}C$ for 1 hr in vacuum. Carbon content, weight loss, dimensional change, and macro defects of the specimen were carefully monitored at each stage of the PIM process. PIMed WC-Co milling inserts reached 100% full density after sinteing. Its mechanical properties and micro-structures were comparable with the press and sintered milling insert. Carbon content of the sintered WC-Co insert was mainly determained by the atmosphere of thermal debinding. By controlling powder loading and injection molding condition, dimensional accuracy could be obtained within 0.4%. We confirm that PIM can not only be an alternative manufacturing method for WC-Co parts economically but also provide a design freedom for more effieient cutting tools.

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Injection Molding Technology for Thin Wall Plastic Part - II. Side Gate Removal Technology Using Cold Press Cutting Process (초정밀 박육 플라스틱 제품 성형기술- II. 냉간 절단 공정 활용 사이드 게이트 제거기술)

  • Heo, Young-Moo;Shin, Kwang-Ho;Choi, Bok-Seok;Kwon, Oh-Keun
    • Design & Manufacturing
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    • v.10 no.3
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    • pp.1-7
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    • 2016
  • In the semiconductor industry the memory and chip were developed to high density memory and high performance chip, so circuit design was also high integrated and the test bed was needed to be thin and fine pitch socket. LGA(Land Grid Array) IC socket with thin wall thickness was designed to satisfy this requirement. The LGA IC socket plastic part was manufacture by injection molding process, it was needed accuracy, stiffness and suit resin with high flowability. After injection molding process the side gates were needed to remove for further assembly process. ln this study, the cold press cutting process was applied to remove the gates. For design of punch and die, the cold press cutting analysis was implemented by$DEFORM-2D^{TM}$ ln consideration of the simulation results, an adequate punch and die was designed and made for the cutting unit. In order to verify the performance of cutting process, the roughness of cutting section of the part was measured and was satisfied in requirement.

Manufacturing of Plastic Noise Barrier Structure Using Extrusion Molding (압출성형을 이용한 플라스틱 방음벽 구조물 제작 연구)

  • Kim, Hyung-Kook
    • Journal of the Korean Society of Manufacturing Process Engineers
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    • v.20 no.6
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    • pp.76-81
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    • 2021
  • A plastic noise barrier is a structure installed to minimize noise, and it is composed of the main plate, sound-absorbing plate, and sound-absorbing material. Plastic noise barrier structures have several advantages compared to other products, such as light weight, anticorrosion, durability, easy assembly, rapid construction, and low costs. In this study, the main and sound-absorbing plates were manufactured through extrusion molding, and the sound-absorbing plate was finished with a press to improve the conventional injection molding. Extrusion molding dies and punch dies were designed, and a profile extrusion-molding system was developed. Thus, inexpensive and efficient sound-absorbing and main plates can be produced, and the noise barrier structure can be assembled rapidly. Additionally, a noise barrier structure with extended service life and excellent quality can be constructed by creating uniform free space to accommodate increased temperatures after assembly and installation.

Study molded part quality of plastic injection process by melt viscosity evaluation

  • Lin, Chung-Chih;Wu, Chieh-Liang
    • Advances in materials Research
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    • v.3 no.2
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    • pp.91-103
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    • 2014
  • A study that demonstrates how to investigate the molded part quality and the consistency of injection process based on the rheological concept is proposed. It is important for plastic material whose melt viscosity is variable with respect to the processing condition. The formulations to couple the melt viscosity with injection pressure and fill time are derived first. Taking calculations of the measured pressure and the time by using these formulations, the melt viscosity in injection process can be determined on machine. As the relation between the injection speed and the melt viscosity is constructed, the influences of the setting parameter of injection machine on the molded part quality can be investigated through evaluating the state of the melt viscosity. In addition, a pressure sensor bushing (PSB) designed with a quick installation feature is also provided and validated. The results show that a higher injection speed improves the tensile strength of the molded part but also the consistency of the molded part quality. This work provides an alternative to evaluate the molding quality scientifically.