Polypropylene/polyethylene (PP/PE) copolymer powder was successfully prepared by solution precipitation method and it was introduced as a binder for sintering commercial PP powder for selective laser sintering (SLS) 3-D printing. Effects of PP/PE copolymer powder on flowability and operation window of SLS 3-D printing were investigated. It was found that PP/PE copolymer powder showed a spherical shape and this resulted in good flowability with the mixing of commercial PP powder. Due to the low melting temperature and cold crystallization temperature of PP/PE copolymer powder, it may be used as a binder for commercial PP powder to sinter at lower temperature during SLS 3-D printing. Since commercial PP powder can be printed at relatively low processing temperature with the aid of PP/PE copolymer, the enhancement of dimensional stability in sintered layer was achieved and this could translate into a better powder recoating process in continuous sintering process

폴리프로필렌/폴리에틸렌(PP/PE) 공중합체를 용액 침전법에 의하여 selective laser sintering(SLS) 3-D 프린팅이 가능한 분말로 제조 후, 이를 상업용 SLS 3-D 프린팅용 폴리프로필렌(PP) 분말에 바인더로 사용하였다. 첨가된 PP/PE 공중합체 분말이 상업용 PP 분말의 흐름특성과 SLS 3-D 프린팅 가공 윈도우에 미치는 영향을 살펴보았다. 제조된 PP/PE 공중합체 분말은 구형으로 만들어져 상업용 PP 분말의 흐름특성을 향상시켜 SLS 3-D 프린팅용 분말 recoating 특성이 개선됨을 알 수 있었다. PP/PE 공중합체의 낮은 용융온도와 냉결정화온도는 PP/PE 공중합체 분말이 바인더로 낮은 온도에서 상업용 PP 분말 융착을 가능하게 하여 융착 후 냉각 과정 중 발생하는 융착층의 치수변형을 최소화할 수 있어 recoating 공정 개선효과를 예측할 수 있다.

Keywords: selective laser sintering 3-D printing, sintering, flowability, PP/PE copolymer powder, dimensional stability