Let the volume flow through the con

令通过控制体积的体积流量为时间上的控制体积流量，而通过右侧的体积流量为泰勒展开公式。根据重量守恒，P——流体密度，g / cm3；T是时间单位，秒；该分量的速度x，y和z指向公式4-2。场论的符号表达式为： <br><br>如果流体不可压缩：它是一个常数。上式简化如下：不限制式<br><br>（4-3）的应用范围。它可用于可压缩和不可压缩的流体，粘性或非粘性流体，固定的不稳定性等。4.2 <br><br>基础理论<br>注塑成型注塑成型过程包括：成型前的准备，注塑成型过程和后塑件处理。本节主要介绍填充，压力和冷却过程。<br>（1）简化充填阶段的流动为：<br>1）熔体是不可压缩的流动；<br>2）填充过程中的比热容和导热率是恒定的；<br><br>3）在填充过程中忽略体积膨胀力和重力。CROS模型可以描述填充过程中的熔体流动。<br><br><br>（2）在<br>在保持阶段的注塑过程中，填充熔融塑料后会有一定的保持时间。应根据不同的产品和材料考虑包装压力。如果包装压力过低，将导致较大的翘曲和不均匀的收缩；如果压力太高，将导致脱模困难，并且容易拉紧产品和其他问题。保持压力通常不大于注射压力，并且熔融温度将在保持过程中相应地改变。通常，<br>在保压过程中的流动分析如下：1）在保压过程中，可以看到雷诺系数较小的熔体。对于蠕变，仅需考虑其他粘度因子；<br>2）忽略了包装过程中粘度和剪切力大的塑料体，忽略了厚度方向压力的微小变化；<br>3）由于塑料零件的长度和宽度对于比厚度大得多的尺寸，可以忽略沿厚度的传热。该过程的简化控制方程如下：

Let the volume flow through the control volume be the control volume flow in time and the volume flow through the right side be the Taylor expansion formula. According to the conservation of weight, P——fluid density, g / cm3; T is the time unit, second; The velocity x, y, and z of The component point to the formula 4-2. The field theory symbolic expression is: <br><br>If the fluid is Incompressible: It is a constant. The formula above is simplified as follows: The<br><br>application range of formula (4-3) is not limited. It can be used for compressible and incompressible fluids, viscous or non-viscous fluids, fixed instability, etc. flows, <br><br>4.2 Basic theory of<br>injection molding The injection molding process includes: preparation before molding, injection molding process and post-plastic parts deal with. This section mainly describes the filling, pressure and cooling process.<br>(1) Simplify the flow at the filling stage as:<br>1) The melt is incompressible flow;<br>2) The specific heat capacity and thermal conductivity during the filling process are constant;<br><br>3) The volume expansion force and weight force are ignored during the filling process. The CROS model can describe the melt flow during the filling process.<br><br><br>(2) In the<br>injection molding process during the holding phase , there will be a certain holding time after the molten plastic is filled. Packing pressure should be considered according to different products and materials. If the packaging pressure is too low, it will cause large warpage and uneven shrinkage; if the pressure is too high, it will cause difficulty in demolding, and it is easy to strain the product and other problems. The holding pressure is generally not greater than the injection pressure, and the melt temperature will change accordingly during the holding process. In general, the flow analysis<br>during the holding pressure process is as follows: 1) In the holding pressure process, the melt with a smaller Reynolds coefficient is visible For creeping, only other viscosity factors need to be considered;<br>2) The plastic body with large viscosity and shear force during the packing process is ignored, and the slight change of pressure in the thickness direction is ignored;<br>3) Due to the length and width of the plastic parts For dimensions much larger than the thickness, heat transfer along the thickness can be ignored. The simplified control equation of the process is as follows:

设通过控制容积的体积流量为控制容积的时间流量，通过右侧的体积流量为泰勒展开式。根据重量守恒，P——流体密度，g/cm3；T是时间单位，秒；组分的速度x、y和z指向式4-2。场论的符号表达式是：<br>如果流体是不可压缩的：它是一个常数。上述公式简化如下：<br>式（4-3）的适用范围不受限制。它可用于可压缩和不可压缩流体、粘性或非粘性流体、固定不稳定性等流动<br>4.2基本理论<br>注塑成型注塑成型工艺包括：成型前的准备、注塑成型工艺及注塑后零件的处理。本节主要介绍填料、压力和冷却过程。<br>（1） 将填充阶段的流量简化为：<br>1） 熔体是不可压缩的流动；<br>2） 填充过程中的比热容和导热系数是恒定的；<br>3） 填充过程中忽略体积膨胀力和重量力。CROS模型可以描述充填过程中熔体的流动。<br>（2） 在<br>注塑成型过程中的保温阶段，将有一定的保温时间后的熔融塑料填充。根据不同的产品和材料，应考虑填料压力。如果包装压力过低，会造成较大的翘曲和不均匀收缩；如果包装压力过高，会造成脱模困难，容易使产品产生应变等问题。保温压力一般不大于注射压力，保温过程中熔体温度会相应变化。一般来说，流量分析<br>在保压过程中：1）保压过程中，雷诺系数较小的熔体出现蠕动现象，只需考虑其它粘度因素；<br>2） 忽略了填料过程中粘性和剪切力较大的塑性体，忽略了压力沿厚度方向的微小变化；<br>3） 由于塑料件的长宽尺寸远大于厚度，沿厚度的传热可以忽略不计。该过程的简化控制方程如下：