关于玻璃纤维的取向和成型品的异向性.doc

关于玻璃纤维的取向和成型品的异向性……（之二）Anisotropy caused by orientation of glass fiber *** (No.2)继续上一讲，本讲对玻璃纤维的取向和成型品的异向性进行说明。 本讲介绍玻璃纤维取向与成型收缩率异向性之间的关系Following the previous issue, anisotropy caused by the orientation of glass fiber is further explained here, particularly with regard to the anisotropy in molding shrinkage this time. 。 成型收缩率的异向性 　下图将成型品内部的断面进行了模式化，其树脂自左至右流动。　由于浇口位于端末、形状薄而细长，所以玻璃纤维自左至右沿流动方向取向。在树脂的流动方向上，由于玻璃纤维的伸张使成型品的收缩受到抑制而导致成型收缩率降低。另一方面，在树脂流动方向的横向垂直方向上，由于玻璃纤维的伸张效果小，致使成型收缩率不是很低，从而使成型品收缩率在树脂流动方向上与树脂流动方向的横向垂直方向上产生异向性。　除了树脂流动方向和树脂流动方向的横向垂直方向之外，在其厚度方向上也会产生异向性。　在上述细长的薄板形状中，厚度方向上的成型收缩率比树脂流动方向的横向垂直方向上还要大。　那么，各方向上的异向性究竟有多大程度的差异呢？下面的图表列出了夺钢GH-25和Fortron 1140A6的成型收缩率数据。我想大家可以看出：树脂流动方向的成型收缩率比树脂流动方向的横向垂直方向小得多。有些材料使用了玻璃纤维一类长径比较大的填充物，在这种中材料因上述取向而导致的成型收缩率异向性较大，它往往成为变形的一大要素。 ※ 请点击。 ※ 请点击。 〈试片形状〉 ※这里汇总了其它各品级制品的成型收缩率数据，请参照。 　在实际制品中，树脂的流动情况非常复杂。由于成型条件会与成型品形状一同产生影响，请您在设计时预测树脂的流动情况，在过去经验和知识的基础上来判断强度和收缩率。　下一讲，将介绍玻璃纤维的取向与成型品机械物性的异向性之间的关系。 Anisotropy in molding shrinkage 　 The following schematic figure shows the cross section of a molding where molten resin flowed from left to right.Since the shape of the molding is thin and long with a gate at one end, the glass fibers are oriented from left to wright along the flow of molten resin. In the direction of resin flow, the shrinkage of molten resin during its solidification is suppressed by the resistance of glass fibers to result in lower molding shrinkage. On the other hand, such resistance is smaller in the perpendicular direction to resin flow, and as a result molding shrinkage is not decreased so much. Therefore, there arises anisotropy in the molding shrinkage between directions parallel and perpendicular to resin flow.Molding shrinkage in a thickness direction is also different from either of that parallel to or that perpendicular to flow direction.In the case of a thin and long plate as shown above, molding shrinkage in thickness direction is estimated to be larger than even that in the direction p