Source: 3DPrint.com
A University of Texas at Arlington thesis student recently investigated thermal annealing to determine how to increase inter-bead bond strength overall in 3D printing processes.
Rhugdhrivya Rane tackled the dilemma of weak tensile strength in FDM parts and whether parameters chosen by the user — such as temperature ranges and pressure gradients — can affect an increase in inter-bead bond strength. The researcher used thermal annealing, and thermal annealing with unidirectional mechanical pressure in the Z direction, 3D printing a variety of specimens in ABS. The method of 3D printing was chosen due to its increased popularity in mainstream manufacturing.
“The parts were printed using two different sets of print parameters: high and low settings, to investigate the effect of heat treatment on both sets of print parameters. The values of temperature, time and applied pressure during heat treatment were varied to obtain a detailed comparative study and the correlation between the given variables and the increase in ultimate tensile strength.” ~ Rane
The discovery was that “higher temperatures and longer exposure to heat produced better tensile strength, along with increased ductility.”
“Though thermal annealing and uniaxial pressure cause an increase in the strength of the parts, the print parameters play a vital role in determining the initial mechanical properties of the parts. When the parts are fabricated with a higher value of flow rate and extrusion temperature, they exhibit significantly higher mechanical properties as compared to parts printed with substandard setting,” concluded the researchers. “Thus, by controlling the print parameters and using the right values of temperature and pressure we can see substantial increase in strength of FDM parts.”
