Monitoring for the effects of extruder nozzle temperature on the micro-mechanical properties of 3D printed phononic artifacts

Investigating the impact of process parameters on the mechanical properties of the printed parts is essential for optimizing 3D Printing/Additive Manufacturing (3DP/AM) processes to produce high-quality parts with desired mechanical requirements, improved product performance, and better reliability. In this proof-of-concept study, a monitoring framework based on Phononic Crystal Artifacts (PCA), which are fabricated alongside the actual build on the same build plate, is introduced and utilized to ultrasonically determine the effects of a printing/ process parameter (here, extruder nozzle temperature) on internal structures and their mechanical properties. A PCA with internal periodic structures is significantly smaller and simpler than the actual build but still represents relevant geometric and mechanical features, which are relevant to the objectives of its quality monitoring program. Here our model quality objective is to introduce a non-destructive process monitoring mechanism and demonstrate the detectability of the effect of the nozzle temperature on the mechanical properties and spectral responses of builds. The current study experimentally shows that the extruder nozzle temperature has a notable effect on the mechanical properties of the printed PCAs. In the reported experiments, the sensitivity of pass-/stop-bands in the spectral domain to the nozzle temperature is also observed and quantified, which implies that the ultrasonic responses of the PCAs are strongly affected by their nozzle temperatures, and their material and micro-scale level interactions of the ultrasonic waves with the PCA phononic textures are strongly modulated. These quantified sensitivities have the potential to be used in closed-loop control and real-time monitoring of chal-lenging 3DP/AM processes and applications.