Bonding Additively Manufactured PLA Materials: Effects of Joint Scarf Angle and Substrate Raster Orientation

Abstract

The aim of this study is to investigate the effect of the scarf angle of the bonding region and the raster orientation of 3D printed substrates for the adhesive scarf joints made of additively manufactured Polylactic acid (PLA) adherends. In the first step, single PLA specimens were 3D printed using the fused filament fabrication (FFF) process in three different raster orientations of 0º, 45º, and 90º. The joints were built with five different scarf angles. The tensile and compression tests of all the specimens were conducted to determine the failure loads for different scarf angles and raster orientations. It is found that the endured load before rupture varies measurably as a function of the raster orientation of printed substrates and scarf angle of the joint, but differently for tensile and compression loadings. An optimization was also done for the joints with substrates of 45? raster orientation and different scarf angles to find a suitable scarf angle, with which the joint can have an acceptable behavior (i.e. reasonable values of the failure load) under both compression and tensile loadings. Consequently, the optimal scarf angle was determined to be about 30?