Industrial-Scale Automation of Zinc Ash Removal: A Robotic Approach to Enhancing Safety and Efficiency in Hot-Dip Galvanizing

This paper presents an industry-scale study on automating zinc-ash removal in hot-dip galvanizing using two robot-guided end-effectors: a mechanical rake and a gas-based nozzle. Initial experiments employed a water bath with floating plastic particles to derive practical process parameters—such as impingement force, immersion depth, and air flow—through comparison factors that transfer results from water to molten zinc. These parameters were then validated in full-scale trials at an industrial galvanizing furnace 1.9 m wide and 7 m long. Both systems proved capable of transporting and removing zinc ash, with the mechanical rake also excelling at clearing oxide layers ("zinc skin") in a manner comparable to manual raking. The gas-based system showed promise, particularly with higher gas throughput or inert gas to curb re-oxidation. Overall, the approach reduces worker exposure to mechanical and chemical hazards and offers pathways to more consistent product quality in contract galvanizing.