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.