Modeling of the Thermal Conditions of Interlayer Bonding During FDM Printing of ABS Plastic

This study investigates the effect of extrusion temperature and print layer thickness on the thermal conditions for interlayer bond formation during FDM printing of ABS plastic. Computer simulations were performed using SOLIDWORKS 2024® with transient thermal analysis. Two print layer thicknesses were considered: 0.10 and 0.25 mm, and three temperatures for the newly deposited layer: 220, 240, and 260 °C. The glass transition temperature of ABS, taken as 105 °C, was used as the criterion for evaluating the thermal state of the interlayer zone. The simulation results showed that increasing the temperature of the newly applied layer increases the depth of the zone with a temperature of Tg ≥ 105 °C and the duration for which the temperature at the interlayer interface remains above the glass transition temperature. For a layer thickness of 0.10 mm, the maximum depth of this zone increased from 0.08 mm at 220 °C to 0.14 mm at 260 °C. For a layer thickness of 0.25 mm, the maximum depth increased from 0.24 to 0.37 mm. Tensile tests were conducted on ABS specimens with layer thicknesses of 0.10 and 0.25 mm to experimentally verify these findings. The experimental tests showed that increasing the thickness of the printed layer from 0.10 to 0.25 mm results in an 8.7% increase in the average maximum tensile stress of ABS plastic and an increase in the calculated relative strain. The experimental results are consistent with trends observed in thermal modeling and show that increasing printed layer thickness leads to deeper, longer-lasting heating of the previously formed material and a higher maximum load withstood by the ABS samples.