LASER SHOCK PEENING PREPRESS

Laser Shock Peening (LSP) Toolpath & Vector Prepress Guide

Laser Shock Peening (LSP) utilizes high-energy nanosecond laser pulses to drive gigapascal shock waves into metallic surfaces under a water confinement overlay, creating deep compressive residual stresses ($> 1.0–2.0\text{mm}$) that dramatically extend fatigue life and foreign object damage (FOD) resistance.

1. Plasma Confinement Physics & Shock Wave Propagation

When a pulsed laser beam ($5–15\text{ J}$, $10–25\text{ ns}$) vaporizes an ablative surface coating under a thin water tamping film, the expanding plasma generates a planar shock wave with pressures exceeding 3–8 GPa, far outperforming conventional shot peening in penetration depth and surface roughness retention.

2. Engineering Specifications & Tolerances

3. Robotic LSP Vector Spot Matrix Prepress Rules

• Overlapping Spot Grid Generation: Program a 60–80% circular spot overlap in both X and Y axes ($\Delta x = d \cdot (1 - \text{Overlap})$) to ensure uniform surface coverage without unpeened tensile cusps.
• Multi-Pass Angular Offset: Rotate sequential peening passes by 45° or 60° vector orientations to homogenize biaxial residual stress distributions.
• Water Jet Normal Alignment: Maintain laser beam and laminar water tamping nozzle within $\pm 3.0^\circ$ normal to 3D contoured airfoil surfaces using 6-axis robotic vector toolpaths.