The Effect of Binder Loading on the Pore Size of 3D Printed PMMA

Abstract

Binder jetting is known to produce porous objects by depositing the binder selectively layer by layer on a powder bed. In this study, the pore size of printed parts and the correlating mechanical properties are investigated on a commercially available PMMA powder binder system. Pore sizes are measured via capillary flow porometry and mechanical properties via tensile tests. Porometry indicates that the pore size stays at a constant level of 22 µm at 5 to 10 wt% binder loading before decreasing to 6 µm at loadings of 30 wt% or higher. The results were compared with the mechanical testing and related to the agglomerate strength model of Rumpf. The highlights of the article are the application of a binder jetted part as a filter and the identification of a close relationship between porosity and mechanical strength, similar to phenomena in agglomeration science.

3D printing stretchable and compressible porous structures by polymerizable emulsions for soft robotics

“…Our printed foams were compared with the literature reports for foams that were 3D printed by various technologies (Fig. 5(C)) 15,16,[21][22][23][24]26,27,[30][31][32]39,[47][48][49][50][51][52][53] to construct the plot, we searched publications under the keywords ''3D printing'', ''foams'' or/and ''porous'', and evaluated only the papers that contained tensile measurements. It should be noted that most publications on photopolymerization-based printing of foams/ porous materials result in stiff polymers 37,54 or ceramics [55][56][57] that cannot elongate and therefore tensile measurements were not reported for.…”

“…The most common porous materials that can be 3D printed are ceramics, metals, and polymer-ceramic composites, which are unsuitable for soft robotics due to their rigid nature. [15][16][17][18][19][20][21][22][23][24][25] On the other hand, polymers such as polylactic acid (PLA), high-density polyethylene (HDPE), PDMS, polystyrene (PS) and polyvinyl alcohol (PVA) can become porous by conventional processes after printing, using foaming agents or sacrificial powders. [26][27][28][29][30][31][32] However, these porous polymers are typically 3D printed using extrusion-based methods, which limits their structural complexity.…”