Robotic friction stir channeling towards high-rectangularity design on complex curved components

Friction stir channeling (FSC) is an innovative technique for machining continuous internal channels in a single step, offering a novel solution for fabricating heat exchanger channels. However, conventional FSC channels are typically processed using low-freedom, high-stiffness equipment (e.g., gantry machines), limiting the application to complex curved components. Here, robotic-FSC (R-FSC) was proposed for fabricating customized channel paths on planar and complex-curved surfaces. The probe with a micro-threaded portion and a non-threaded portion was designed to regulate material flow behavior. Channels with high rectangularity (> 90%) were successfully achieved on both two-dimensional (2D) plates and three-dimensional (3D) curved surfaces, with consistent cross-sectional shape along the entire path. The passive cooling efficiency is 9.5 times that of active cooling when reducing temperature from 90 °C to 45 °C, confirming the functional viability of R-FSC channels. This method enables channel fabrication on diverse surfaces, demonstrating significant adaptability to various scenarios. • The probe design integrating micro-threaded and non-threaded segments achieves channel rectangularity exceeding 90%. • Channels were machined on 2D flat plates and 3D curved surfaces for the first time using R-FSC. • The material flow behavior was analyzed to validate the rationality of the probe design.