Freeform Surface Generation by Atmospheric Pressure Plasma Processing Using a Time-Variant Influence Function

Based on a controllable chemical reaction, atmospheric pressure plasma processing (APPP) can achieve efficient material removal even when the tool influence function (TIF) size is reduced to several millimeters, resulting in its great application potential for generating freeform surfaces. However, the TIF changes with the local dwell time, introducing nonlinearity into processing, because of the influence of the plasma thermal effect on chemical reactions. In this paper, a freeform generation method using a time-variant TIF is presented and validated. First, the time-variant removal characteristics of APPP and its nonlinear influence on freeform surface generation are analyzed. Then, the freeform surface generation concept is proposed based on controlling the local volumetric removal. Consequently, the dwell time calculation method is developed to suppress the nonlinearity induced by the time-variant TIF. Finally, the developed method is evaluated by the simulation and experimental analysis of the complex structure generation process. Results show that the proposed method can reduce the nonlinear influence of the time-variant TIF by reasonably calculating dwell time, promoting the application of APPP in freeform surface generation.