注塑模具设计过程中浇口尺寸对塑料制品力学性能的影响

以高密度聚乙烯（PE-HD）为原料，采用自行设计加工的一套1模4腔注射标准试样模具进行注塑，通过调整熔体温度、模具温度和注射压力等工艺参数，考察了不同浇口截面尺寸的模具对注塑样品拉伸、冲击和弯曲性能的影响。结果表明，模具浇口截面尺寸修改后，注射试样的力学性能明显提升，其中，拉伸强度、冲击强度、弯曲强度和弯曲模量最高分别提升了3.40 %、79.86 %、18.11 %和113.36 %；模具浇口修改后注塑所的样品充填饱满，无塌陷等缺陷；修改浇口后的模具设计整体结构布局合理，可为同类标准测试样的成型模具设计提供有益借鉴。

Influence of Sprue Size on Mechanical Properties of Plastic Products in Design of Injection Mold

In this paper, a self-designed one?mold four-cavity injection standard mold was employed to fabricate the high-density polyethylene (PE-HD) samples through injection molding with different sprue sizes. By changing the injection molding process parameters such as melt temperature, mold temperature, and injection pressure, the mechanical properties of injection-molded samples including tensile, impact, and bending behaviors were investigated. These samples exhibited a significant improvement in mechanical properties when using the sprue with modified cross?sectional dimensions, and their tensile strength, impact strength, bending strength and bending modulus increased by about 3.40 %, 79.86 %, 18.11 % and 113.36 % in maximum, respectively. The relationship between the injection process parameters and properties was also established. After modification for sprue, the injection-molded sample could be fully filled, and there was no defect like collapse observed. The mold designed by this work has a reasonable overall structural layout after the modification of sprue. This design can provide a useful reference for mold design of test samples with a similar standard.