Abstract: In order to find out the cause of the fracture failure of the plastic spring seat and come up the solution, the failure sample was analyzed by microscope, scanning electron microscope, Fourier infrared spectrometry, and synchronous thermal analyzer. The results show that the failure part is made of PA66 + GF, and the cooperation between PA66 resin and GF at the fracture point is uneven and non-dense, the main cause of failure is stress concentration which occurred in during installation. To avoid this kind of fracture, it is suggested that the injection molding process of PA66 should be controlled to ensure the uniform distribution of PA66 and GF, and the plastic spring seat should be correctly placed in the assembling to avoid stress concentration and reduce fracture.

Key words: Plastic spring seat; Failure analysis; Brittle fracture; Stress concentration

摘要： 某塑料弹簧限位座在工厂批量生产安装过程中出现了断裂失效的问题，为了寻找失效 原因并提出解决方案，对失效件样品采用显微镜、扫描电子显微镜、傅里叶红外光谱、同步 热分析仪进行综合分析。结果表明，该失效件材质为 PA66+GF，断裂处存在树脂 PA66 与 GF 配合不均且不密实的情况；断裂是由于在安装中受到较大应力导致出现了应力集中，为失效 的主要原因。为避免该种断裂，建议在材料加工过程中对 PA66 的注塑工艺进行控制，尽量保 证 PA66 和 GF 分布均匀；其次在安装中放置限位座平整，避免出现应力集中，降低断裂的问 题发生。

关键词: 塑料弹簧限位座；失效分析；脆性断裂；应力集中