3D pyrography as a process tunable feature in polylactic acid/olive wood composite material extrusion

Purpose This study aims to investigate polylactic acid (PLA)/olive wood (PLA/OW) composites for material extrusion (MEX) and frames 3D pyrography as a process-tunable surface appearance feature, linking printing conditions to surface texture and colour. Design/methodology/approach PLA/OW filaments (0–20 Wt.% OW) were compounded and printed while varying extrusion temperature and printing speed. FTIR, differential scanning calorimeter and thermogravimetric analysis supported thermo-chemical assessment and oscillatory rheology aided printability evaluation. Surface texture was quantified by confocal areal roughness, and colour was measured in CIELAB and expressed as ΔE00. Multifactor analysis of variance and second-order response surfaces were used to map process–appearance relationships within the tested range. Findings Increasing OW reduced crystallinity and thermal stability and increased melt viscoelasticity, narrowing the practical processing window. Roughness rose with OW content and was further governed by printing conditions. Temperature dominated chromatic change, promoting darkening (lower L*) and higher ΔE00, whereas higher printing speeds reduced thermal exposure and helped preserve lighter shades. The response surfaces provide consistent maps for combined texture–colour tuning. Practical implications The approach can support aesthetic tuning using a single biofilled filament, potentially reducing the need for multiple coloured materials, filament changeovers and purge-related waste in design-oriented MEX applications. Originality/value This work provides a quantitative framework that treats 3D pyrography in PLA/OW as a controllable process feature, jointly mapping colour (CIELAB/ΔE00) and surface texture as outcomes of MEX parameters, enabling reproducible tone modulation without post-processing.