Experimental Methods for Annealing 3D Printed PLA Parts:
As noted above, polylactic acid (PLA) is used throughout this article particularly for its ability to form crystalline microstructures once annealed. An electric convection style oven is most typically used for annealing PLA 3D prints. Since PLA has a very low glass transition temperature in amorphous form, the initial temperature set point used is typically 170°F (76.7°C). This particular experiment was run using 3-time intervals (10, 30 and 60 minutes) at 170°F to better understand the impact of the time based variable on the formation of the crystalline microstructures.
The samples in this experiment were printed with a 0.4mm nozzle at 0.1mm layer heights, 0% infill with three shells. The purpose of this was to measure the influence of rapid annealing on the outer surface of the part. This observation is particularly useful for thin walled objects. For every material, ten samples were created which did not pass through any treatment and those act as the experimental control. This experiment specifically tested the Z-axis strength, or interlayer bonding of both standard and annealed PLA. 
Data that was collected during the experiment is shown in graph against stress strain value.