Optimization of FDM process parameters and dimensional error of double-arrowhead auxetic honeycomb structures

Material extrusion additive manufacturing provides a flexible and low-cost route for fabricating complex auxetic structures; however, the dimensional accuracy of thin-walled composite honeycombs remains difficult to control because of thermal accumulation, extrusion instability, and layer-by-layer deposition effects. For double-arrowhead auxetic honeycombs, wall-thickness deviation can directly affect the relative density and the consistency of mechanical response. This study, therefore, investigates how key fused deposition modeling process parameters influence the dimensional error of PETG-CF double-arrowhead auxetic thin-walled honeycomb structures and how a reproducible low-error process window can be established. A four-factor, three-level Box–Behnken design combined with response surface methodology was employed to evaluate the effects of printing speed, printing temperature, bed temperature, and layer height on dimensional accuracy, with wall-thickness error selected as the primary response variable. The results show that the wall-thickness error model is statistically significant and that the response is mainly governed by significant main effects and quadratic effects. The optimized process parameters were determined as a printing speed of 279 mm/s, a printing temperature of 222 °C, a bed temperature of 46 °C, and a layer height of 112 μm. Confirmation experiments yielded an average wall thickness of 1.0389 mm and a mean absolute error of 0.0389 mm. This work extends process-parameter optimization from simple printed specimens to geometrically sensitive auxetic thin-walled honeycomb structures and provides practical guidance for the high-consistency fabrication of composite auxetic metamaterials.