共查询到19条相似文献,搜索用时 69 毫秒
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注塑冷却管网的简化计算 总被引:1,自引:0,他引:1
给出了作者推导的冷却管道椭圆积分项计算公式,分析了它的复杂性,采用降维处理方法,将原来的二维管道单元简化为一维线单元,简化了计算,提高了计算速度,缩短了计算时间。 相似文献
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在用边界元方法进行注塑冷却分析时,形成的矩阵方程为满阵,当单元数目超过一定值时,计算机则变得无能为力.针对这一问题,本文介绍一种新的计算方法,首先将单元分组,求出组内单元的平均温度,再利用得到的结果进一步计算组内每一个单元上的温度.采用这种方法,能够有效缩短计算时间,使计算时间仅为常规方法的1/4甚至更少.另外,通过单元合并减少了计算的数据量,改善了因计算机截断误差积累导致计算结果异常的情况,使得冷却分析能处理的单元数目较常规方法提高1倍以上. 相似文献
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平板塑件瞬态传热解析解及其在冷却分析中的应用 总被引:4,自引:0,他引:4
简要介绍了建立冷却分析数学模型的两种方法,指出了循环迭代模型的不足,推导了平板塑件瞬态传热解析解,找出循环平均热流与边界温度的线性关系表达式,并将它应用于注塑冷却分析,建立了冷却分析的迭代模型,取代原来的循环迭代模型,从而取消了原冷却分析中的中间迭代计算,有效地减少了冷却分析的迭代次数,提高了运算效率。另外,循环迭代求解平板塑件温度场采用的是有限差分法,即近似数值解,而迭代模型采用的是解析解,从理论上讲结果更精确,所以对提高计算结果的精度有一定的改善作用。 相似文献
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带筋平板注塑件的冷却模型分析 总被引:2,自引:0,他引:2
通过对带筋平板注塑件的分析,提出了该类注塑件的冷却物理模型,简化后用数学模型表征。将精确分析解法与积分近似解法相结合,求得了固液两相内的温度分布、固液相位置函数和中心层温度冷至熔点所需的冷却时间。讨论了带筋平板注塑件保压冷却阶段的最佳工艺设定时问。 相似文献
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结晶型塑料注塑平板冷却模型的研究 总被引:6,自引:3,他引:6
本文从注塑的实际出发,针对注塑塑料平板的冷却凝固本质,提出了有限厚度区域内注塑平板的冷却模型,用精确分析解法与积分近似解法相结合,进行了理论推导,求得了固液两相内的温度分布和平板中心层温度冷却至熔点所需的冷却时间。 相似文献
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A theoretical mathematical model is presented to describe the temperature distribution and the rate of phase change in the injection molding process of crystalline plastics. Under some assumptions, an exact closed form is solved with the use of an internal technique. The model was tested by measuring the temperature profile in a slab mold instrumented with thermocouples. Measurements of temperature profiles in the center of the polymer slab compare well to model prediction. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 102: 2249–2253, 2006 相似文献
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Yung-Hsiang Chang Min-Chi Chiu Shia-Chung Chen Che-Wei Chang Chia-Yen Tseng 《Polymer Engineering and Science》2020,60(12):3072-3085
Injection molding is one of the most widely-used processes for the production of plastic parts, due to the utilization of diverse materials, the complex product-shape moldability, and the rapid mass production. In relation to the environmental issues, light-weight technology and green molding solutions are becoming more important. Microcellular injection molding technology is one of the green molding solutions for saving materials, as well as reducing the weight of molded parts. However, the molding process brings about some defects, including a sliver flow mark on the surface and uneven mechanical properties that are caused by the uneven cell size and their distribution within the part. Dynamic molding temperature control technology seems to be an effective way of improving the product quality. Until recently, there has been very little discussion about high-efficiency cooling methods. A new complex mold for a cooling system has been designed. The basis cooling ability of different materials was investigated. The complex mold design has a faster cooling rate, and it has a greater surface temperature uniformity. This cooling technology was used to improve the quality of microcellular injection molded parts, which improves the glossy finish by about 73%. The results show that the faster cooling rate brings about the more uniform cell size with higher cell density from 9.43E+11 to 1.92E+12 cells/cm3. Otherwise, the cell size reduced from 192.92 to 84.97 μm. 相似文献
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Plastic injection molding (PIM) is well known as a manufacturing process to produce products with various shapes and complex geometry at low cost. Determining optimal settings of process parameters critically influence productivity, quality, and cost of production in the PIM industry. To study the effect of the process parameters on the cooling of the polymer during injection molding, a full three‐dimensional time‐dependent injection molding analysis was carried out. The studied configuration consists of a mold having cuboids‐shaped cavity with two different thicknesses and six cooling channels. A numerical model by finite volume was used for the solution of the physical model. A validation of the numerical model was presented. The effect of different process parameters (inlet coolant temperature, inlet coolant flow rate, injection temperature, and filling time) on the cooling process was considered. The results indicate that the filling time has a great effect on the solidification of the product during the filling stage. They also show that low coolant flow rate increases the heterogeneity of the temperature distribution through the product. The process parameter realizing minimum cooling time not necessary achieves optimum product quality and the complete filling of the cavity by the polymer material. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2009 相似文献
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注塑成型过程中,熔体在型腔中的流动和传热对制品质量性能有重要的影响.为了预测注塑制品的收缩、翘曲和力学性能,精确预测充填过程的流动及传热历史是十分必要的.本文考虑熔体的可压缩性及相变的影响,将充填过程中熔体的流动视为非牛顿可压流体在非等温状态下的广义Hele-Shaw流动.采用有限元/有限差分混合方法求解压力场和温度场,采用控制体积法跟踪熔体流动前沿,并应用Visual C++实现了注塑充填过程的可压缩流动分析.为了保证能量方程各项在单元内边界的连续性,结点能量方程各项由单元形心处的离散值加权平均获得,因而,能量方程在计算区域内整体求解.对两个算例进行了分析,模拟结果与实验结果的对比,验证了本文数值算法及程序. 相似文献
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交流伺服电机制动能量、液压系统回油能量、机筒加热散发能量等能源再生利用是注塑机节能技术不可缺少的一个部分,分析研究了这些节能技术的应用和发展的趋势。液压差动、循环的回油能源再生利用系统主要应用于锁模油缸,降低溢流量的蓄能器系统主要应用于超大型注塑油缸。注塑机能源再生利用技术提高了能量的利用率,根据各种注塑机的实际情况,应用和研发能源再生利用的新技术、新结构、新工艺,使注塑机的节能技术达到一个新水平。 相似文献