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首页> 外文期刊>Journal of Applied Polymer Science >Response of a sequential-valve-gate system used for thin-wall injection molding
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Response of a sequential-valve-gate system used for thin-wall injection molding

机译：用于薄壁注塑成型的顺序阀浇口系统的响应

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Sequential injection molding using a valvegate-controlled hot runner system has attracted attention for industrial applications in recent years. Because of the complexity of the operation mechanisms, a commercial valve gate usually delays for about 0.3-0.5 s once the valve-opening command is given. The signal-to-operation delay is acceptable for the conventional injection molding of large parts. However, this operation delay limits its application to thin-wall molded parts for computer, communication, and consumer electronics, for which the required filling time is very short. In this study, a gas-driven fast-response sequential-valve-gate system was developed for thin-wall injection molding by the adoption of valve-gate control performance. The characteristics and verifications of the valve-gate opening were monitored with a charge-coupled device (CCD) camera (nonmelt condition) and cavity pressure transducers and an accelerometer (melt-filled condition). The influence of the tolerance between the inner piston and cylinder and the gas pressure on the valve-gate opening was investigated in detail. Tensile bar parts 1 mm thick were used for the molding experiments. The delay time has been found to be intimately related to the response of the gas-pressure delivery controlling the valve-gate movement. In a nonmelt environment, the delay time of the valve-gate opening decreases with increasing driven gas slightly. In a melt-filled environment, the delay time is quite sensitive to the operating gas pressure because of the extra resistance between the shaft and the melt. A threshold pressure as high as 100 bar is required to keep the delay time below 15 ms. With the proper choice of the piston size and driven gas pressure, the delay time can be reduced to about 8 ms in a nonmelt environment and to about 12 ms in a melt-filled environment. Molding using this improved system for sequential valve opening can provide thin-wall injection parts without a weld line, and good cosmetic quality and better tensile strength require a lower injection pressure than molding using single-gate and concurrent-valve-gate opening. (c) 2005 Wiley Periodicals, Inc.
机译：近年来，使用气门控制的热流道系统的顺序注射成型引起了工业应用的关注。由于操作机构的复杂性，一旦给出开阀命令，商用阀门通常会延迟约0.3-0.5 s。对于大型零件的常规注塑成型，信号操作延迟是可以接受的。但是，这种操作延迟限制了其在计算机，通信和消费类电子产品的薄壁模制零件中的应用，为此所需的填充时间非常短。在这项研究中，通过采用气门控制性能，开发了一种用于薄壁注塑成型的气体驱动快速响应顺序气门系统。使用电荷耦合器件（CCD）摄像机（非熔融状态），型腔压力传感器和加速度计（熔融填充状态）监控阀门浇口的特性和验证。详细研究了内部活塞和气缸之间的公差以及气压对气门关闭的影响。 1 mm厚的拉伸杆零件用于模制实验。已经发现，延迟时间与控制阀闸运动的气压输送的响应密切相关。在非熔融环境中，阀门打开的延迟时间会随着驱动气体的增加而略有减少。在熔体填充的环境中，由于轴和熔体之间的额外阻力，延迟时间对工作气体压力非常敏感。为了使延迟时间保持在15 ms以下，需要高至100 bar的阈值压力。与所述活塞大小和驱动气体压力的适当选择，延迟时间可以在充满熔融的环境中降低到约8毫秒的nonmelt环境和至约12毫秒。使用此改进的系统进行连续阀打开的成型可以提供没有焊接线的薄壁注塑零件，并且与使用单浇口和同时阀式浇口的成型相比，良好的外观质量和更好的拉伸强度需要更低的注射压力。 （c）2005年Wiley Periodicals，Inc.

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