注射成型工艺对高铁轨距挡板稳定性影响

Influence of Injection Molding Process on Stability of High-Speed Railway Gauge Baffle

轨距挡板是高铁WJ-8型扣件轨道结构的重要组成部分,该制品使用玻璃纤维增强聚酰胺66材料注射成型,但在注射成型过程中往往会出现成型不足、凹痕、熔接痕、飞边、气泡、银丝、变形等一些质量问题。在保证注塑机的技术参数和模具结构均符合注射成型要求的前提下,在注塑加工中通过对注射成型五大要素如温度、压力、速度、时间、位置的调整来改善制品塑化不良、浇口流痕以及尺寸等质量问题。经过工艺调整,料筒温度提高10℃、注塑压力提高0.5~1.0 MPa、背压提高0.5 MPa可以解决塑化不良、浇口流痕等质量问题。

The track gauge baffle is an important part of the track structure of high-speed rail WJ-8 fastener.The product uses glass fiber reinforced polyamide 66 material for injection molding,but some quality problems such as insufficient filling concave mark,fusion mark,flying edge,bubble silver wire deformation often appear in the process of injection molding.In the technical parameters of injection molding machine and mold structure under the premise of all conform to the requirements of the injection molding,five elements such as temperature,pressure,speed,time and position in the injection molding processing were adjusted to improve poor plasticizing,gate flow marks as well as the size and so on quality issues.After process adjustment,the temperature of cylinder increasing by 10℃,the injection pressure increasing by 0.5–1.0 MPa and back pressure increasing by 0.5 MPa can solve the quality problems of poor plasticizing and gate flow marks.