Simulation System for Electrostatic Coating and Automated Robotic Coating Strategy Development for H-Beams of Various Scales *

The teaching process in robotic coating operations remains heavily reliant on operator expertise, often requiring repetitive cycles to achieve the desired quality. This increases lead times and material waste. To address this, we propose a predictive simulation system for electrostatic coating, enabling smart manufacturing by automating coating path generation. Our system integrates history-dependent kinematic modeling of the coating material before the nozzle and hydrodynamic behavior after application, based on rheological properties. Unlike prior studies, which were limited to non-electrostatic applications, our method incorporates particle dynamics under electrostatic force using the Navier–Stokes equation. It also considers variables such as voltage, discharge rate, spray angle, and gun speed. We validated this digital twin approach through physical experiments, achieving a coating film thickness prediction accuracy within ±15 μm. This enables parameter-based process optimization without requiring repeated physical trials. Based on this system, we developed a scale-selectable coating strategy tailored to H-beams, commonly used in industrial settings. The strategy supports full automation across various web and flange dimensions (Web: 168–420 mm, Flange: 0-70 mm), replacing manual processes. The effectiveness of the strategy was confirmed through both simulation and experimental validation, demonstrating the potential to reduce worker exposure to spatter and to enhance safety and efficiency in automated manufacturing.