Maximizing mechanical properties and minimizing support material of PolyJet fabricated 3D lattice structures

Abstract

Anisotropy of mechanical properties and support material removal are the two main problems when fabricating 3D lattice structures by integrated printing via additive manufacturing (AM) technology. Aiming at these two problems, a snap-fit method is introduced into PolyJet technology to fabricate polymer lattice structures with four typical configurations, namely BCC, BCC-Z, FCC and octet. Printing materials and printing time in this novel method are both reduced by over 80 % compared to the conventional printing method. Uniaxial compression tests indicate that both the strengths and energy absorptions of the four kinds of snap-fitted lattices are increased by over 100 % compared to the integrated counterparts. The effect of strut thickness on compressive responses of the snap-fitted and integrated lattices is investigated. With the decrease of strut thickness, the advantage in the strength of the snap-fitted lattices becomes more obvious compared to the integrated counterparts. Ideal maximum strength models based on yielding, elastic buckling and inelastic buckling are developed and are able to predict the compressive peak strengths of the snap-fitted PolyJet lattices. This study opens up an avenue for the fabrication of large scale 3D printed lattice structures with optimal mechanical properties and without support material removal problem.