Anatomical and Structural Characterization of Ghanaian Indigenous Vegetable-Tanned Leathers for Laser Engraving and Cutting

Abstract

This study investigated the anatomical and structural characteristics of Ghanaian Indigenous Vegetable-Tanned Leathers (GIVTLs) and evaluated their suitability for laser engraving and cutting. Although digital fabrication technologies are increasingly used in art, design, and material-processing environments, limited empirical evidence explains how indigenous vegetable-tanned leathers respond to laser exposure. Thirty samples of vegetable-tanned goat-skins obtained from traditional tanneries in Kumasi, Tamale, and Bolgatanga were categorized into four anatomical zones: bend, shoulder, belly, and neck. Using adapted ISO/ASTM-aligned procedures, the study assessed thickness, moisture content, macro-grain structure, and mechanical integrity of the selected leathers. Results showed that the bend zone had the highest dimensional stability, lowest moisture content, compact grain structure, and strongest mechanical cohesion, making it the most suitable zone for diode-laser processing. The shoulder demonstrated moderate suitability, whereas the belly and neck recorded higher moisture levels, irregular thickness, porous grain structures, and weak structural cohesion. These conditions increased the likelihood of inconsistent engraving, darkening, and poor edge quality. Interpreted through laser-material interaction theory and structure-property relationships, the findings demonstrate that collagen density, moisture gradients, and grain compactness influence heat diffusion, energy absorption, and ablation behaviour. The study provides material-centred evidence for zone-specific parameter selection and supports the development of localized guidelines for precision laser processing of GIVTLs.