dip pre-treatment plant, this is where you literally dunk your components into chemical baths. Complete submersion. Crescent Techno actually does this really well with their PLC-based transportation systems, or you can go old-school with electrically operated overhead hoists. https://crescenttechno.com/dip-vs-spray-pre-treatment-plants-what-you-actually-need-to-know-about-industrial-surface-prep-in-india/