1.集美大学海洋装备与机械工程学院，福建厦门 361021； 2.精覃模具制造有限公司，福建厦门 361023
Injection mold design of inner tooth water pipe joint and CAE simulation
LI Bo1, LUO Shanming1, LI Yi1 , CHEN Zhihang2
1.College of Marine Equipment and Mechanical Engineering,Jimei University,Xiamen 361021,China; 2.Jingtan Mold Manufacturing Co.,Ltd.,Xiamen 361023,China
摘要：针对一端带有内螺纹和另一端为光孔的水管接头，设计了一套带有齿轮传动+抽芯液压缸的自动脱螺纹机构和斜导柱侧抽芯机构的三板式注塑模具。 首先，结合塑件的结构特点 ，确定了点浇口进胶以及浇口位置和直流循环式的冷却回路，利用模流仿真分析软件moldflow对确定的模流分析模型进行注塑成型工艺过程模拟分析。结果表明，塑料熔体的充填时间、缩痕指数、气穴分布以及翘曲变形量等成型工艺参数都在合理范围之内 ，验证了浇注系统和冷却系统设计的合理性。其次，对模具结构进行设计 ，将主分型面取在塑件的轴心面上，其余两个分型面顺序分型实现浇注系统凝料的自动脱落。 由于塑件为带内螺纹的管状零件，针对内螺纹脱模难的问题，设计了齿轮传动机构驱动螺纹侧型芯旋转和抽芯液压缸的直线移动的两套运动机构实施自动脱螺纹，塑件光孔部分的成型和抽芯采用斜导柱侧抽芯机构来实现。通过模流分析，验证了模具结构的合理性，并且缩短了模具设计的开发周期，有效地提高了塑件的成型质量。
Abstract：For water pipe joint fittings with internal thread at one end and unthreaded hole at the other end, a set of three-plate injection mold with automatic threading removal mechanism of gear drive + core-pulling hydraulic cylinder and the core-pulling mechanism on the side of the inclined guide post was designed. Firstly, combined with the structural characteristics of the plastic parts, the point gate feeding, gate location and direct fluent circulating cooling circuit were determined. For the determined mold flow analysis model, the moldflow simulation analysis software moldflow was used to simulate the injection molding process. The results show that the molding process parameters of filling time, shrinkage index, air hole distribution and warping deformation are within the reasonable range and the design of the casting system and the cooling system is justified. Secondly, the mold structure was designed, the main parting surface was taken on the axis of the plastic parts, and the other two parting surfaces were sequentially parting to realize the automatic falling off of the condensate in the casting system. Because the plastic parts are tubular parts with internal thread, aiming at the problem of internal thread release difficulty, two sets of motion mechanisms, which drive the rotation of the threaded side core and the linear movement of the core-pulling hydraulic cylinder were designed to implement automatic threading removal, the forming and core-pulling of the unthreaded hole part of the plastic part were realized by the core-pulling mechanism on the side of the inclined guide post. Through the moldflow analysis, the rationality of mold structure was guaranteed, the development cycle of mold design was shortened, and the molding quality of plastic parts was effectively improved.
Keywords：water pipe joint; automatic threading removal; moldflow analysis; core-pulling mechanism; injection mold
LI Bo，LUO Shanming，LI Yi，et al. Injection mold design of inner tooth water pipe joint and CAE simulation[J]. Engineering Plastics Appli‐cation，2024，52(1)：95-101.