Mechanical strength of welding zones produced by polymer extrusion additive manufacturing

As more manufacturing processes and research institutions adopt rapid prototyping as a key el-ement in their design strategies and finished products, the resulting mechanical properties of parts produced through additive manufacturing (AM) must be characterized and understood. In polymer extrusion (PE), the strength of the weld formed by the deposition of one layer of extruded material on top of the previous layer is typically the strength limiting location of the part. Understanding the role of processing conditions, specifically extruder velocity and extruder temperature, on the over-all strength of the weld will allow optimization of PE-AM parts. Here, the fracture toughness of a single weld is determined through a facile “trouser tear” Mode III fracture experiment. The actual weld thickness is observed directly by optical microscopy (OM) characterization of cross sections of PE-AM samples. The dependence of weld strength on extruder velocity and temperature is re-ported for acrylonitrile butadiene styrene materials.