Interplay between heat accumulation and material removal in ultrafast laser processing of PVC

Abstract The control of heat-affected modifications is a major challenge in ultrafast laser processing of polymers due to their low thermal diffusivity and phase transition temperatures. While these effects are typically localized in the vicinity of the ablation region, the interaction may evolve from positive heat-affected deformation to efficient material removal, depending on the irradiation conditions. In this work, we investigate how pulse duration (220 fs – 32 ps), beam radius (40 –118 μm), and repetition rate (100 Hz – 60 kHz) govern the laser-induced response of poly(vinyl chloride) (PVC) under 1030 nm ultrafast laser irradiation. These results reveal that heat accumulation strongly influences the interaction behavior even under fluence conditions above the single-pulse ablation threshold. Under heat accumulation conditions, heat-affected modifications decrease beyond a certain repetition rate, while ablation remains efficient. This behavior suggests that material removal may reduce the fraction of deposited energy contributing to heat diffusion into the surrounding region. These findings suggest that, in polymers with low thermal diffusivity, efficient material removal can contribute to reducing heat-affected modification at repetition rates well below the GHz regime typically discussed in the context of ablation cooling. This enables the investigation of this regime under conditions where the influence of additional effects, such as plasma or particle shielding is reduced. This work provides new insights into the interplay between heat accumulation and material removal in ultrafast laser processing, offering guidelines for the controlled fabrication of surface structures and the optimization of laser processing conditions.