理论上说，尼龙塑料件加工当被点蚀或侵蚀过的模具表表已精确仿造，投射到制品表表的光线会产生漫反射。因而，表表会出现黯区。对拥有较少精确仿造的表表，漫反射景象就会得到节造进而制品表表出现好的光泽成效

与加工参数有关的原因与改进措施见下表：

1、保压太低 提高保压压力
；

2、保压功夫太短 提高保压功夫
；

3、模壁温度太低 提高模壁温度
；

4、熔料温度太低 提高熔体温度
；

与设计有关的原因与改进措施见下表：

1、模壁截面差距太大 提供更均一的模壁截面
；

2、资料积留过多或棱边尺寸过大 预防资料积留过沉或棱边尺寸过大
；

In theory, when the surface of the mold that has been pitting or eroded during the processing of nylon plastic parts has been accurately replicated, the light projected onto the surface of the product will undergo diffuse reflection. Therefore, there will be dark areas on the surface. For surfaces with less precise replication, diffuse reflection phenomenon will be controlled, resulting in a good gloss effect on the surface of the product

The reasons and improvement measures related to processing parameters are shown in the following table:

1. Raise the holding pressure if it is too low;

2. If the holding time is too short, increase the holding time;

3. Raise the mold wall temperature if it is too low;

4. Raise the melt temperature if the melt temperature is too low; The reasons and improvement measures related to design are shown in the following table:

1. The significant difference in mold wall cross-section provides a more uniform mold wall cross-section;

2. Excessive material accumulation or large edge size should be avoided to prevent excessive material accumulation or large edge size;