Enhancing the Longitudinal Compressive Strength of Freeform 3D-Printed Continuous Carbon Fiber-Reinforced Polymer...

Area of Science:

• Materials Science
• Additive Manufacturing
• Composite Materials

Background:

• Carbon fiber-reinforced polymer (CFRP) composites exhibit low compressive strength along the fiber direction, a weakness exacerbated by 3D printing.
• Traditional manufacturing methods like out-of-autoclave-vacuum-bag-only (OOA-VBO) have limitations in optimizing composite properties.

Purpose of the Study:

• To introduce and evaluate a novel magnetic compaction force-assisted additive manufacturing (MCFA-AM) method for producing CFRP laminates.
• To investigate the effect of carbon nanofiber (CNF) z-threads and varying magnetic pressures on the compressive strength of 3D printed CFRP.

Main Methods:

• Developed and utilized the MCFA-AM technique to print CFRP laminates with CNF z-threads (ZT-CFRP).
• MCFA-AM employs magnetic force for levitation, deposition, and compaction of CFRP prepregs, enabling mold-less and substrate-less printing.
• Conducted longitudinal compressive tests on ZT-CFRP/MCFA-AM samples printed at 0.5 bar and 0.78 bar magnetic rolling pressures.

Main Results:

• ZT-CFRP/MCFA-AM samples printed at 0.5 bar showed comparable compressive strength (-1.00% difference) to traditional OOA-VBO processed CFRP.
• Samples printed at 0.78 bar magnetic rolling pressure demonstrated enhanced compressive strength (+7.42% improvement) compared to OOA-VBO samples.
• The MCFA-AM method effectively reduces voids during the printing of CFRP laminates.

Conclusions:

• The MCFA-AM method is a viable technique for 3D printing CFRP composites with improved longitudinal compressive strength.
• Incorporating CNF z-threads and optimizing magnetic compaction pressure can overcome the inherent weakness of CFRPs in compressive loading.
• MCFA-AM offers a promising alternative for manufacturing high-performance CFRP parts with reduced defects and enhanced mechanical properties.