Adhesion at the Weld Line in 3-D Printing: A Model System

Abstract

A new creative and manufacturing revolution is underway with the advent of 3-D printing.  For fused deposition modeling, applications can be limited to hobbyists if the weld lines do not knit together during printing (adhere) and contribute to strength of the part. The part exhibits good cohesion between along the horizontal direction, but much poorer adhesion in the layered Z direction. This vertical Z-axis strength is the focus of this research. A method for testing the weld line adhesion has been developed, ABS materials and some nylon have been tested to improve adhesion through introduction of a solvent or adhesive.  Solvent plasticization of the forming layer, ABS slurry adhesive and “Glue Stick” or PVA adhesive mechanical test results are reported.  Mechanical tests were developed in analogy to the T-peel test detailed in ASTM spec D1876.