粉末老化对选择性激光烧结尼龙2200拉伸性能的影响

Effect of Powder Aging on Tensile Properties of Selective Laser Sintering PA2200

选择性激光烧结能直接制造复杂工件,工艺已日趋成熟。PA12尼龙粉末是这一工艺常用的材料。成形过程中,大量粉末材料并没有被烧结,这部分粉末的回用对降低成本有重要意义。然而,未烧结粉末在过程中受高温老化,老化粉末的回用对成形件性能的影响尚不明确。使用EOS P110选择性激光3D打印系统和PA2200尼龙粉末,通过多次粉末回用系统考察了选择性激光烧结条件下粉末老化对成形件拉伸性能的影响。结果表明,随着回用次数的增加,粉末逐渐老化,分子结合力增强,熔点升高,流动性下降,成形件中未熔颗粒逐渐增加。新粉成形件的拉伸强度为41.5 MPa,粉末1次回用时增加到49.0 MPa,而后逐渐减小到7次回用时的37.1 MPa;而延伸率则从新粉成形件的20.5%依次减少到7次回用粉成形件的6.7%。

Selective Laser Sintering (SLS) can manufacture complex parts directly, which displays potential application. PA12 powder is common used in SLS process. During sintering process, lots of powder are not sintered. It reminds that recycling of unsintered powder may cut the cost of SLS process significantly. However, although ageing of the recycled powder has been proved during the process, influence of the aged powder on properties of the sintered parts is still unclear. Effects of aged PA2200 on mechanic properties of the sintered parts were investigated systematically by EOS P110 printer. The results show that the melting point of PA2200 is raised with the increase of powder’s recycling times and the amount of unmelted particles in the sintered parts is also growing. It is also discovered that the tensile strength increases from 41.5 MPa of the new powder sintered sample to 49.0 MPa of the first recycling powder sintered sample, and then decreases to 35.1 MPa of the 7 th recycling powder sintered sample. The elongation at break decreases from 20.5% of the new powder sintered sample to 6.7% of the 7 th recycling powder sintered sample.