• Title, Summary, Keyword: Injection Speed

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Investigation of the Filling Unbalance and Dimensional Variations in Multi-Cavity Injection Molded Parts (다수 캐비티의 사출성형품에서 충전의 불균형과 성형품 치수 편차의 교찰)

  • Kang, Min-A;Lyu, Min-Young
    • Polymer(Korea)
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    • v.32 no.6
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    • pp.501-508
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    • 2008
  • Small injection molded articles such as lens and mobile product parts are usually molded in multi-cavity mold. The problem occurring in multi-cavity molding is flow unbalance among the cavities. The flow unbalance affects the dimensions and physical properties of molded articles. First of all, the origin of flow unbalance is geometrical unbalance of the delivery system. However, even the geometry of the delivery system is well balanced, cavity unbalance occurs. This comes from the temperature distributions in the cross-section of runner. Temperature distribution depends upon injection speed because heat generation near runner wall is high at high injection speed. Among the operational conditions, injection speed is the most significant process variable affecting the filling unbalances in multi-cavity injection molding. In this study, experimental study of flow unbalance has been conducted for various injection speeds and materials. Also, the filling unbalances were compared with CAE results. The dimensions and weights of multi-cavity molded parts were examined. The results showed that the filling unbalances vary according to the injection speeds and resins. Subsequently, the unbalanced filling and pressure distribution in the multi-cavity affect the dimensions and physical states of molded parts.

The Effects of Injection Molding Conditions on Uniformity and Brightness of Light Guide Plate (도광판의 균일도 및 휘도에 사출성형조건이 미치는 영향)

  • Lee Sung-Hee;Kim S.W.;Lee H.S.;Kim J.D.
    • Proceedings of the Korean Society of Precision Engineering Conference
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    • pp.1609-1612
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    • 2005
  • The effects of injection molding conditions on the uniformity and brightness of light guide plate(LGP) with micro-patterns were investigated in the present study. An injection molding system for stampers with mirco-pattern was designed and manufactured to perform experiment. Variations of injection molding speed, mold and melt temperature for LGP were considered in this work. Also, injection molding characteristics of LGP were investigated by numerical analysis using plastic injection molding commercial code. It was shown that injection molding conditions such as injection speed, melt temperature and mold temperature can have an effect on the uniformity and brightness of light guide plate.

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A Study on a Simulation of a Fuel Injection System in a Large Low-Speed Marine Diesel Engines (박용 대형 저속 디젤기관 연료분사계통의 시뮬레이션에 관한 연구)

  • 강정석;이창식;조권회;최재성
    • Journal of Advanced Marine Engineering and Technology
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    • v.24 no.6
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    • pp.43-52
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    • 2000
  • In this study, a simulation program was developed, which could simulate a fuel injection system for low-speed marine diesel engine. The fuel injection system was divided into fuel injection pump, high pressure pipe and fuel injection valve. The unsteady flow in the high pressure injection pipe was analyzed by the method of characteristics, considering cavitation and variation of fuel density and bulk modulus. It was confirmed that the simulation results were good agree with experimental results of injection pressure and quantity at the high pressure distributor in fuel injection system for the training ship "M/V Hannara". And the effects of the atomizer hole diameter, maximum needle lift, plunger diameter and nozzle opening pressure were also investigated with simulating results.g results.

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A Study of Technical Adapting on Injection Molding for Magnesium Alloy (마그네슘합금 사출성형의 기술적용에 관한 연구)

  • 강태호;김인관;최준영;김영수
    • Proceedings of the Korean Society of Precision Engineering Conference
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    • pp.833-836
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    • 1997
  • Magnesium alloys are one of light weight material. Strength and stiffness of Magnesium alloys are enough to use for commercial product. Demand for strong, lightweight parts several computer and electronics have driven much of Magnesium injection molding's growth so far. And it is eighth most abundant resource on earth. In electronic device, electromagnetic interface and electrostatic discharge can affect performance. Magnesium injection molding is similar to normal plastic injection molding process. But some process condition is different. Especially injection speed and process temperature are so differs from other injection molding system. It just start for make something. But Magnesium injection molding is one of best alternate process for producing metal alloy part.

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A Study on the Emission Characteristics of NOx in Medium Speed Diesel Engine (중속 디젤기관의 질소산화물 배출특성에 관한 연구)

  • 우석근;윤건식;윤영환
    • Journal of Advanced Marine Engineering and Technology
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    • v.24 no.4
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    • pp.526-534
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    • 2000
  • In this study, the characteristics of exhaust emissions in medium speed diesel engine under various operating conditions were investigated through experiments to derive the optimum conditions for minimizing the exhaust emissions, especially, nitrogen oxides. The 355 KW$\times$1200 rpm medium speed diesel engine was intensively examined to investigate the trend of exhaust emissions in case that the parameters affecting combustion conditions such as fuel injection timing, intake air temperature and pressure, engine speed and load were changed. The exhaust emissions for 9 sets of medium speed diesel engine were analyzed in addition. From this study, NOx level could be reduced by 30~50% through the adjustment of retarded fuel injection timing, lowered intake air temperature and increased charging air pressure.

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Wide Speed Direct Torque and Flux Controlled IPM Synchronous Motor Drive Using a Combined Adaptive Sliding Mode Observer and HF Signal Injection

  • Foo, Gilbert;Rahman, M.F.
    • Journal of Power Electronics
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    • v.9 no.4
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    • pp.582-592
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    • 2009
  • This paper proposes a new speed sensorless direct torque and flux controlled interior permanent magnet synchronous motor (IPMSM) drive. Closed-loop control of both the torque and stator flux linkage are achieved by using two proportional-integral (PI) controllers. The reference voltage vectors are generated by a SVM unit. The drive uses an adaptive sliding mode observer for joint stator flux and rotor speed estimation. Global asymptotic stability of the observer is achieved via Lyapunov analysis. At low speeds, the observer is combined with the high frequency signal injection technique for stable operation down to standstill. Hence, the sensorless drive is capable of exhibiting high dynamic and steady-state performances over a wide speed range. The operating range of the direct torque and flux controlled (DTFC) drive is extended into the high speed region by incorporating field weakening. Experimental results confirm the effectiveness of the proposed method.

Shrinkage Behaviors of PA6 polymer according to Shape Ratio of Product in Injection Molding (PA6 사출성형품의 형상비에 따른 성형수축 거동)

  • 최윤식;한동엽;정영득
    • Proceedings of the Korean Society of Precision Engineering Conference
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    • pp.308-311
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    • 2004
  • Nowadays, plastic industry has needed to produce parts that require high precision and quality. To make a high precision and quality part, before injection molding, plastic material is investigated about their properties such as shrinkage, warpage, etc. In this study, experiments were conducted with PA6(polyamid) to figure out shrinkage behavior according to three type aspect ratio of samples. The injection speed that affects on shear rate, molecular orientation within plastic part was determined as main variable of experiment. As a result of experimental study, part shrinkage had a tendency to be decreased by increasing injection speed and aspect ratio of samples.

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An Experimental studies Spray characteristic of Pintle type Nozzle on High Pressure Chamber (고온.고압용기에서의 핀틀노즐의 분무특성에 관한 실험적 연구)

  • 송규근;정재연;오은탁;류호성;안병규
    • Proceedings of the Korean Society of Marine Engineers Conference
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    • pp.67-73
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    • 2002
  • The characteristics of fuel spray influence on the engine performances such as power, fuel economy and emissions. therefore, the measurement of fuel spray characteristics is very important for the improvement of heat engine. The factor which controls the fuel spray is injection pressure, ambient pressure, engine speed et al.. In :his study, We measured spray angle, spray penetration and spray tip velocity considering injection pressure(10,14㎫), ambient pressure(3,4,5㎫), fuel pump speed(500,700,900rpm) in the high temperature and pressure chamber. Experimental results are summarized as follows: 1) Injection pressure influence on the characteristics of spray namely As Injection pressure Is increased, spray angle is decreased but spray penetration and spray tip velocity is increased. 2) Spray angle, spray penetration is increased by increasing the fuel pump speed. 3) Ambient pressure plays an important role in spray characteristics.

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Ground Speed Control of a Direct Injection Sprayer

  • Koo, T.M.;Sumner, H.R.
    • Proceedings of the Korean Society for Agricultural Machinery Conference
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    • pp.500-510
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    • 1996
  • A Direct injection -mixing total -flow -control sprayer was developed and evaluated . The system provided precise application rates and minimized operator exposure to chemicals as well as providing a possibility for recycling container so f unused chemicals that can causes environmental contamination. Chemicals were metered and injected proportionally to the diluent flow rate to provide constant concentrations. The main diluent flow was varied in response to changes in travel speed. Experimental variables of the sprayer were the control interval, the sensitivity of flow regulating valve, the tolerance of control object and the sensitivity of the injection pump system. The optimal performance of the flow control system was with an average response time of 8.5 sec at an absolute steady state of error of 0.067 L/min (0.8% of flow rate). The average response time of the injection rate was -0.53 sec and the coefficient of variation (CV) of concentration was 3.2%.

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A study on monitoring for process time and process properties by measuring vibration signals transmitted to the mold during injection molding (사출성형공정에서 금형에 전달되는 진동 신호 측정을 이용한 성형 단계별 공정시간과 공정특성의 모니터링에 대한 연구)

  • Lee, Jun-han;Kim, Jong-Sun
    • Journal of the Korea Society of Die & Mold Engineering
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    • v.14 no.3
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    • pp.8-16
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    • 2020
  • 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.

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