Quality Control of 3D-Printed Aerospace Lattice Structures

The Challenge

Metal lattice structures produced by laser powder bed fusion (LPBF) enable complex three-dimensional geometries impossible to achieve through conventional manufacturing, making them invaluable for aerospace and automotive lightweighting applications. However, the LPBF process can introduce internal defects such as small porosities that compromise structural integrity. These defects are invisible to visual inspection, and CT scanning every part is prohibitively expensive and slow for production environments. Manufacturers need a practical non-destructive inspection method for high-value lattice components.

The Solution

This research validated impulse excitation testing as a non-destructive inspection method for LPBF lattice structures. The study examined both lattice and bulk samples produced in high-strength A205 aluminum alloy, including specimens with intentionally manufactured defects at known locations.

By comparing resonant frequencies between defect-free reference samples and potentially defective parts, IET successfully detected selectively placed internal defects. The frequency shifts caused by internal voids and porosities provide clear pass/fail criteria without requiring complex signal interpretation or expensive equipment.

Key takeaway: Resonant frequency differences between defect-free and defective A205 aluminum lattice samples provided reliable detection of selectively placed internal defects.

Results

The research demonstrated that IET reliably detects LPBF manufacturing defects in complex lattice geometries based on resonant frequency differences. This validates impulse excitation as a practical quality control solution for AM production environments, fast enough for 100% inspection of high-value aerospace and automotive lattice components where internal defect detection is critical.