A Comparative Analysis of Selected Methods for Determining Young's Modulus in Polylactic Acid Samples Manufactured...

Area of Science:

• Materials Science
• Polymer Engineering
• Additive Manufacturing

Background:

• 3D printing, specifically fused filament fabrication (FFF/FDM), is widely used for producing polymer components.
• Accurate characterization of material properties, such as Young's modulus, is crucial for engineering applications.
• Polylactic acid (PLA) and acrylonitrile-butadiene-styrene (ABS) are common 3D printing thermoplastics.

Purpose of the Study:

• To compare the effectiveness of three methods for determining the Young's modulus of PLA and ABS.
• To evaluate the influence of processing temperatures on the measured Young's modulus.
• To assess the agreement between destructive and nondestructive testing techniques.

Main Methods:

• Samples of PLA and ABS were manufactured using the FFF/FDM 3D printing technique at processing temperatures ranging from 180 °C to 230 °C.
• Young's modulus was measured using two nondestructive techniques: impulse excitation technique (IET) and ultrasonic (US) method.
• Results were compared against values obtained from static tensile tests (STT).

Main Results:

• All three methods showed similar trends in Young's modulus changes with varying processing temperatures.
• The US method yielded values closer to the STT results compared to IET.
• Despite closer agreement, the US method's error exceeded 10% in all comparisons with STT.

Conclusions:

• Destructive (STT) and nondestructive (IET, US) methods for determining Young's modulus in 3D-printed PLA and ABS can yield significantly different results, with discrepancies of approximately 1 GPa.
• The ultrasonic method shows potential for improved accuracy over IET when compared to static tensile tests, but further refinement is needed to reduce error.
• Processing temperature influences the Young's modulus of 3D-printed polymers, a factor that should be considered when selecting characterization methods.