Vat Photopolymerization Additive Manufacturing of WC-Co Hardmetals Enabled by In Situ Polymerization-Induced...

Area of Science:

• Materials Science
• Additive Manufacturing
• Nanotechnology

Background:

• Additive manufacturing of hardmetals faces challenges in printing resolution and mechanical strength.
• Vat photopolymerization offers potential for complex hardmetal part fabrication.
• Improving slurry properties is key to overcoming current limitations.

Purpose of the Study:

• To develop a vat photopolymerization method for fabricating high-resolution, high-strength hardmetal parts.
• To enhance the photocuring ability and sedimentation stability of WC-Co slurries.
• To achieve complex structures and high surface quality in 3D-printed hardmetal components.

Main Methods:

• In situ polymerization-induced microencapsulation of tungsten carbide (WC) powder with polystyrene (PS).
• Preparation of WC-Co slurry with WC@PS for vat photopolymerization.
• Sintering process to fabricate dense hardmetal parts.
• Characterization of slurry properties, curing depth, part density, hardness, and surface roughness.

Main Results:

• Microencapsulation of WC powder (WC@PS) significantly increased slurry curing depth by 650% (32 to 336 μm).
• Achieved 3D-printed hardmetal parts with 99.5% relative density and 86.9 HRA hardness.
• Obtained a surface roughness (Ra) of 2.26 μm, approaching theoretical limits.
• Demonstrated a printed drilling bit capable of easily drilling through metal sheets.

Conclusions:

• Vat photopolymerization assisted by sintering can fabricate complex hardmetal parts with high surface quality and performance.
• Polymerization-induced microencapsulation effectively enhances slurry properties for 3D printing.
• This approach enables the production of miniature, high-performance hardmetal components via 3D printing.