选择性激光烧结(SLS)是增材制造技术中的一种, 在聚酰胺2200(PA2200)的SLS成形过程中, 大量的粉末没有被烧结, 这部分未烧结粉末的回用对降低成本具有重要意义。然而, 未烧结粉末的性能因成形过程中高温的影响而发生改变, 回用次数对成形件性能的影响规律尚不明确。使用EOS P110 3D打印系统和EOS PA2200粉末系统考察了粉末回用次数对SLS PA2200成形件硬度和冲击韧性的影响。结果表明：随着回用次数增加, 回用粉末的熔点升高；当回用次数超过2次后, 成形件内部未熔粉末和孔洞的数量增多, 成形件韧性和硬度下降；粉末回用次数不超过2次时, 成形件的冲击韧性下降得较少, 硬度得到一定提高。

Selective laser sintering (SLS) is a kind of additive manufacturing technology. A large amount of powders are not sintered during the SLS forming of polyamide 2200 (PA2200), and the reuse of the unsintered powders is important for reducing the cost. However, the high temperature during the SLS process changes the performance of unsintered powders, and the effect of powder recycling on the properties of the formed samples is not yet clear. The influences of powder recycling times on hardness and impact toughness of the sintered samples are systematically investigated with the help of EOS P110 system and EOS PA2200 powders. The results show that the melting point of the recycled powders increases with the increase of recycling times of the powders. When the recycling times exceeds two, the unmelted powders and pores inside the formed samples increase, and the toughness and hardness of the formed samples decrease. When the recycling times of powders is less than two, the impact toughness of the formed samples declines slightly and its hardness increases.