• Title/Summary/Keyword: and molding depth

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Investigation of Micro Cutting Characteristics for Tungsten-Carbide Green Part (초경 그린파트 마이크로 절삭가공 특성 분석)

  • Kim, G.H.;Jung, W.C.;Yoon, G.S.;Heo, Y.M.;Kwon, Y.S.;Cho, M.W.
    • Transactions of Materials Processing
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    • v.19 no.3
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    • pp.191-196
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    • 2010
  • Tungsten-carbide as typical difficult-to-cut material has excellent mechanical properties such as high thermal resistivity, mechanical strength and chemical durability. However, it is next to impossible for tungsten-carbide to be fabricated the needed parts by cutting process. In this study, for establishing the micro fabrication method of tungsten-carbide for micro injection or compression molding core, the investigation on micro cutting characteristics of tungsten-carbide green part which is made by powder injection molding process and easy to cut relatively was performed. For this, micro endmilling experiments of tungsten-carbide green part were performed according to various cutting conditions. Finally, the wear trend of micro endmill and the appearance of micro rib according to feed-rate and cutting depth per step were analyzed through SEM images of micro cutting feature and microscope images of micro tools.

Fabrication of the Micro-structured DVD-RAM Substrates (미세 형상을 갖는 DVD-RAM 기판의 성형에 관한 연구)

  • 문수동
    • Proceedings of the Korean Society for Technology of Plasticity Conference
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    • 2000.04a
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    • pp.167-170
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    • 2000
  • Recently the sub-micron structured substrates of 0.74 ${mu}ell$ track pitch and 800 $\AA$groove depth are required for DVD-RAM and the track pitch is expected to be narrower as the need for the information storage density is getting higher. For the accurate replication of the land-groove structure in the stamper to the plastic substrates it is important to control the injection -compression molding process such that the integrity of the replication for the land-groove structure is maximized. in the present study polycarbonate substrates were fabricated by injection comression molding and the land-groove structure regarded as one of mold temperature and the compression pressure on the integrity of the replication were examined experimentally. An efficient design methodology using the response surface method (RSM) the central composite design(CCD) technique and the analysis-of-variance (ANOVA) was developed to obtain the optimum processing conditions which maximize the integrity of the replication with a limited number of experiments.

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A Study on the Novel Prediction of Mold Wall Thickness for a Deep Depth Injection Mold (깊이가 깊은 사출 금형의 새로운 측벽 두께 설계에 관한 연구)

  • Hwang, S.J.;Lyu, M.Y.
    • Transactions of Materials Processing
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    • v.17 no.7
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    • pp.528-533
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    • 2008
  • Cavity in the mold is exposed to high pressure during injection molding operation. Injection molded articles with deep depth are often demanded as design variety increases. Subsequently mold becomes weak and deformation increases as the mold depth increases. Thus the injection molds for deep depth articles should be designed to hold out high pressure or stress concentration and large deformation. Through this study, equation for mold design was examined and suggested novel method to determine equation for mold design with deep depth. Novel equation developed in this study was modified from beam theory considering cantilever and two points bending situation while previous equation was modified from just cantilever bending situation. The validity of novel equation was verified through computer simulations for various mold side and wall thickness.

A method of mold wall thickness design for a deep depth injection mold (깊이가 깊은 사출 금형의 측벽 설계 방법)

  • Hwang, S.J.;Lyu, M.Y.;Kim, D.W.;Kim, S.Y.;Shin, K.S.;Kim, K.Y.
    • Proceedings of the Korean Society for Technology of Plasticity Conference
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    • 2008.05a
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    • pp.301-304
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    • 2008
  • The cavity of mold is exposed to high pressure during injection molding operation. Injection molded articles with deep depth are often demanded as design variety increases. Mold becomes weak and deformation increases as the mold depth increases. Thus the injection molds for deep depth articles should be designed to hold out high pressure or stress and large deformation. Through this study, equation for mold design was examined and suggested novel method to determine equation for mold design with deep depth. Novel equation developed in this study was consisted with cantilever and two points bending while previous equation was modified from just cantilever bending. The validity of novel equation was verified through computer simulation.

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A Study of STS 316L Threaded Elbow Fitting Fabrication by Metal Injection Molding (금속사출성형을 이용한 STS 316L 밸브피팅 제작에 대한 연구)

  • Kim, J.Y.;Kim, S.J.;Chung, S.T.;Ahn, S.
    • Transactions of Materials Processing
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    • v.24 no.2
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    • pp.121-129
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    • 2015
  • A net-shape forming of small and complex-shaped metal parts by metal injection molding (MIM) has economic advantages in mass production, especially for STS 316L valve fitting. STS 316L offers excellent corrosion resistance, but it has poor machinability, which is a limitation in using it for a cost-effective production where both forging and machining are employed. Simulation and experimental analysis were performed to develop a MIM STS 316L 90° elbow fitting minimizing trial and error. A Taguchi method was used to determine which input parameter was the most sensitive to possible defects (e.g. sink mark depth) during the injection molding. The final prototype was successfully built. The results indicate that the simulation tool can be used during the design process to minimize trial and error, but the final adjustment of parameters based on field experience is essential.

Optimum Working Condition of Surface Roughness for End-Milling Using Taguchi Design (다구찌 기법을 이용한 엔드밀 가공시 최적 표면거칠기를 위한 가공조건선정)

  • 이상재;배효준;전태옥;박흥식
    • Proceedings of the Korean Society of Precision Engineering Conference
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    • 2003.06a
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    • pp.553-556
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    • 2003
  • End-milling have been used in the industrial world because it is very effective to the manufacture of mechanical parts with various shape. Recently the end-milling processing is needed the high-precise technique with good surface roughness and rapid time in aircraft, automobile part and molding industry. Therefore this study carried to decide the optimum cutting condition for surface roughness and rapid manufacturing time using design of experiment and ANOVA. From the results of experimentation, surface roughness have an effect on cutting direction, spindle speed and depth of cut. And then the optimum condition used Taguchi design is upward cutting in cutting direction, 600rpm in spindle speed, 240mm/min feed rate, 2mm in axial depth of cut and 0.25mm radial depth of cut. By using design of experiment, it is effectively represented shape characteristics of working surface in end-milling.

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A Study on the Sliding Wear Characteristicsn of the Die Steel for the Cold Molding (냉간성형용 Die 강의 미끄럼 마멸특성에 관한 연구)

  • 전태옥;박흥식;류경곤
    • Tribology and Lubricants
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    • v.9 no.1
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    • pp.38-44
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    • 1993
  • The present study was undertaken to investigate the dry wear characteristics of die steel STD 11 for cold molding. The wear test was experimentally carried out under different conditions using a wear device, which was made in laboratory, and in which annular surfaces of wear testing specimens wear rubbed in dry sliding condition with varying the sliding speed, contact pressure, and sliding distance. The wear loss by variation of sliding speed was much in 0.3 m/sec and less in higher speed range above its sliding speed according to formation of the boundary lubrication film. The critical sliding speed with maximum value of the specific wear rate switched over to lower speed side according. as contact pressure increased. The critical sliding distance was increased with decrease in oxidation reaction velocity. The depth below subsurface showing maximum hardness (Hv) came out at the position, $60 \mu m$, of the maximum shear stress due to strain hardening.

Moldability of graphite composite bipolar plate for PEM fuel cell (PEM 연료전지 분리판용 흑연입자 복합재의 성형성 평가)

  • Lee H.S.;Kim S.G.;Kim H.S.;Ahn S.H.
    • Proceedings of the Korean Society of Precision Engineering Conference
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    • 2006.05a
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    • pp.89-90
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    • 2006
  • The bipolar plate is a major component of the PEM fuel cell stack, which takes a large portion of stack cost. In this study, as alternative materials fur bipolar plate of PEM fuel cells, graphite composites were fabricated by compression molding. Graphite particles mixed with epoxy resin were used as the main substance to provide electric conductivity. Flow channels were fabricated by compression molding, and design of experiments (DOE) was applied to the tests to evaluate moldability. Results showed that land width and channel depth were two significant factors for moldability, and channel width had little influence on the moldability.

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A structural analysis of deep depth injection mold to investigate the cause of crack (깊이가 깊은 사출금형의 크랙 원인 파악을 위한 강도해석)

  • Choi, S.H.;Lyu, M.Y.;Kim, D.W.;Kim, S.Y.;Shin, K.S.;Kim, K.Y.
    • Proceedings of the Korean Society for Technology of Plasticity Conference
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    • 2008.05a
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    • pp.297-300
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    • 2008
  • High pressure is involved during injection molding operation specially packing phase. Cracks in the mold are often occurred by high cavity pressure. In this study, structural analysis of mold has been performed using commercial softwares, Abaqus and Ansys, to investigate cause of crack in the injection mold. Structural analysis contains four cases: stress distribution according to the cavity pressure, stress concentration according to the boundary conditions, stress concentration for inter-locking design of mold, and stress concentration for distributed cavity pressure. Through this study it was observed that the locations of stress concentrations were coincident with locations of crack. Robust mold design is being required to withstand high cavity pressure.

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Ecological Study on the Seed Germination and Emergence of Overwintered Stump of Bulrush(Scirpus juncoides Roxb.) (올챙고랭이(Scirpus juncoides Roxb.) 종자발아(種子發芽) 및 월동(越冬) 주기부(株基部)의 출아생태(出芽生態)에 관한 연구(硏究))

  • Guh, J.O.;Huh, S.M.
    • Korean Journal of Weed Science
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    • v.6 no.2
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    • pp.110-123
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    • 1986
  • To know the ecological pattern of bulrush (Scirpus juncoides Roxb.) seeds and overwintreed stumps in germination and sprouting responses as affected by different temperature (7 trt.), light intensity (5 trt.), shading intensity (S trt.), light quality (specturm spectrum; 6 trt.), soil acidity (7 trt.), stump sizea (weight base; 5 trt.), and molding depth (6trt.), respectively, this serial studies were conducted by use of growth chamber, incubator, Wagner pot and petri-dish. Most efficient treatment was obtained from 25-$35^{\circ}C$ temperature, higher light intensity in 2-11 klux range, 95% shading intensity, clear and yellow film for seeds/clear and blue film for stumps, soil pH 5.53, 3-4g stump weight, 0-5% wxygen concentration, 1 ㎝ flooding depth for seeds, and 1-1.5cm molding depth for seeds/0.5-1.0 cm molding depth for stumps, respectively, among others.

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