Enabling Industrial Re-Use of Large-Format Additive Manufacturing Molding and Tooling.

Area of Science:

• Materials Science
• Manufacturing Engineering
• Sustainable Manufacturing

Background:

• Large-format additive manufacturing (LFAM) utilizes advanced composites like carbon fiber (CF)-filled polycarbonate (PC) as a cost-effective alternative to metals.
• Mechanical recycling of end-of-life (EOL) CF-PC components is explored to reduce feedstock costs and environmental impact.
• Previous research indicates minimal performance impact from recycling CF-PC at lab and pilot scales.

Purpose of the Study:

• To evaluate the properties and printability of mechanically recycled CF-PC processed through industrial-scale LFAM.
• To assess the feasibility of integrating recycled CF-PC into industrial additive manufacturing applications.
• To identify areas for technological innovation to improve recycled material performance.

Main Methods:

• EOL CF-PC components were subjected to industrial shredding and melt compounding.
• The recycled material was processed using LFAM equipment.
• Material properties were analyzed, including fiber length, molecular weight (GPC), density (pycnometry), thermal performance (DMA), and tensile properties (X- and Z-directions).

Main Results:

• Recycled CF-PC exhibited a 24.6% reduction in average fiber length.
• Tensile strength decreased by 21% in the X-direction, while tensile modulus decreased by 39%.
• Z-direction tensile modulus increased by 4%, density rose by 6.8%, and heat deflection temperature (HDT) retained over 97% of its original value.

Conclusions:

• Mechanically recycled CF-PC can be integrated into industrial LFAM applications, offering reduced costs and environmental benefits.
• Despite some property degradation (e.g., fiber length, tensile strength), critical performance metrics like modulus and HDT remain largely intact.
• Technological advancements are needed to mitigate fiber degradation and further enhance the performance of recycled CF-PC for wider adoption in circular manufacturing practices.