Recycling of <scp>3D</scp> printed poly(lactic acid) stamps for footwear and leather goods

Abstract The recycling of poly(lactic acid) (PLA) for three‐dimensionally (3D) printed stamps for the footwear and leather goods industry was explored in this work. The use of 3D printed stamps reduces cost and time‐to‐market of footwear and leather goods, and the environmental sustainability is leveraged by the recycling of thermoplastic 3D printed stamps. PLA scrap with different recycling cycles was separated and shredded to prepare pellets for filament extrusion. Recycled PLA filaments, without adding any virgin raw material, were extruded and used in a fused filament fabrication process to print stamps for leather marking. The results show that the control of the filament diameter is hindered by the number of recycling cycles of the material, for which an increase in the diameter variation was observed from 0.01 mm to 0.06 mm. These defects jeopardize the fused filament fabrication printing process, promoting underextrusion and stringing in the 3D printed stamps. The quality of the stamps was assessed, and poor surface quality was observed for stamps printed with PLA recycled two and three times. In the case of stamps printed with virgin PLA and one‐time recycled PLA, the results are similar regarding the stamp and marking visual quality. For PLA recycled two and three times, it was observed that the defects in the top layers are transferred to the leather after stamping. Finally, the durability of the stamps was assessed by performing 40 cycles of stamping. It was observed that different defects appear in the stamps, such as wall bending, delamination and wall deformation. This work shows the viability of the use of 100% recycled PLA for 3D printed stamps, without the use of additives, for leather stamping, with a decrease in quality in the stamping quality after the second recycling cycle. © 2026 Society of Chemical Industry.