工艺参数对注射成型塑磁颗粒流动性能的影响

Influence of process parameters on the flow properties of injection molded plastic magnetic particles

采用尼龙作为粘结剂,与锶铁氧体磁粉和添加剂经过双螺杆挤出机加热混炼、冷却制粒得到注射成型磁塑颗粒,注射成型获得注塑磁体,研究了磁粉形貌、磁粉粒度分布、尼龙配方体系和挤出温度等工艺参数对塑磁颗粒流动性能的影响。结果表明:磁粉加工方式和塑磁产品制备工艺参数对塑磁颗粒的流动性具有重要影响;球磨机磨粉,颗粒形貌接近球形,流动性好;而使用砂磨机磨粉,颗粒形状趋向片状,流动性较差;球磨时间越长,磁粉平均粒度越小,塑磁颗粒流动性能越差;通过调整尼龙配方体系可以改善加工流动性能和力学性能,制备不同性能的注塑磁体;PA6塑磁颗粒混炼挤出温度优选240~250℃。

Nylon was used as binder,and strontium ferrite magnetic powder and additives were heated,kneaded and cooled in a twin-screw extruder to obtain injection molded magnetic plastic particles.Injection molding was used to obtain injection molded magnets.The effects of magnetic powder morphology,particle size distribution,nylon formulation system and extrusion temperature on the flow properties of plastic magnetic particles were studied.The results show that the processing method of magnetic powder and the processing parameters of plastic magnetic products have important effects on the fluidity of plastic magnetic particles.When the ball mill is used for grinding,the particle morphology is close to spherical and the fluidity is good.When the sand mill is used for grinding,the particle shape tends to be flake and the fluidity is poor.The longer the milling time,the smaller the average particle size of the magnetic powder,and the worse the flow performance of the plastic magnetic particles.By adjusting the nylon formulation system,the processing flow and mechanical properties can be improved,and the injection magnets with different properties can be prepared.The mixing and extrusion temperature of PA6 plastic magnetic particles is preferably 240—250℃.