# Numerical Modelling of Pulsed Laser Surface Processing of Polymer Composites

## TL;DR

This paper presents a numerical model to predict and optimize pulsed laser surface processing of polymer composites, improving uniformity and efficiency.

## Contribution

A three-tier numerical workflow is introduced to model laser texturing of polymer composites with microspheres, capturing ablation, thermal softening, and capillary reshaping.

## Key findings

- Scan overlap and shielding dynamics strongly influence groove homogeneity more than average laser power.
- The workflow generates quantitative metrics like mean depth and uniformity index for process optimization.
- Controlled reflow can smooth surface peaks while maintaining groove depth.

## Abstract

Filled-polymer coatings enable functional surfaces for selective metallisation, wetting control and local conductivity, but pulsed-laser texturing is often limited by process non-uniformity caused by scan kinematics and plume shielding. Here, we develop a three-tier numerical workflow for nanosecond pulsed-laser surface treatment of a thermoplastic coating containing glass microspheres (baseline case: PLA matrix with Vf = 0.20; spheres represented via an effective optical transport model). Tier 1 predicts spatially resolved ablation depth under raster scanning, using an incubation law and regime switching (no-removal/melt-limited/logarithmic ablation/blow-off) coupled to a dynamic shielding factor. Tier 2 computes the 1D transient (pulse-averaged) temperature field and the thickness of the thermally softened layer. Tier 3 models post-pulse capillary redistribution of the softened layer to estimate groove reshaping. The simulations show that scan overlap and shielding dynamics dominate groove homogeneity more strongly than average power alone: under identical average power, variations in local pulse count and shielding lead to significant changes in depth statistics and regime fractions. The workflow produces quantitative maps and summary metrics (mean depth, P5–P95 range, uniformity index and regime fractions) and demonstrates how controlled reflow can smooth peaks while preserving groove depth. These results provide a predictive tool for laser parameter selection and process optimisation prior to experimental trials.