Polyamide 12 Materials Study of Morpho-Structural Changes during Laser Sintering of 3D Printing

Area of Science:

• Materials Science
• Polymer Science
• Additive Manufacturing

Background:

• Polyamide (PA)-12 is a crucial material in additive manufacturing (AM).
• Understanding powder morphology and structural properties is vital for 3D laser printing quality.
• Real-world, large-scale production powders were investigated.

Purpose of the Study:

• To characterize the morphology and structural properties of fresh and scrap PA12 powders used in 3D laser printing.
• To evaluate crystallinity, surface properties, and particle characteristics.
• To compare properties between fresh and recycled PA12 powders.

Main Methods:

• X-ray Diffraction (XRD), Fourier-Transform Infrared Spectroscopy (FTIR), and Differential Scanning Calorimetry (DSC) for crystallinity analysis.
• Specific surface area evaluation and porosity measurements.
• Scanning Electron Microscopy (SEM) for morphology, particle size, and shape analysis, complemented by laser diffraction and image analysis.

Main Results:

• Fresh PA12 powder exhibited inhomogeneous particle size distribution, defective particles, a relatively high specific surface area, large lamellar crystallite size, and low crystallinity.
• Scrap PA12 powder demonstrated approximately 2% higher crystallinity compared to fresh powder.
• Scrap PA12 particles had a very low specific surface area (<1 m²/g), often sintered as twin particles, and presented polyhedral shapes.

Conclusions:

• Fresh PA12 powders for AM present challenges due to particle inhomogeneity and defects.
• Recycled PA12 powder shows potential benefits with higher crystallinity and reduced specific surface area, though particle sintering is observed.