12th International Conference on Zinc & Zinc Alloy Coated Steel Sheet - GALVATECH 2021

Over the past two years, four CGLs have installed an online, surface cleanliness monitor system utilizing a non-contact, laser ablation technique to evaluate the contamination layer on the moving sheet. The CGL operators using the system obtain unprecedented detail about the sheet’s surface cleanliness along the entire length of each coil.

The system has been improved over the last two years with customer feedback and hard lessons learned about laser quality. The most notable system enhancements are the addition of a different industrial laser technology and an all-new, instrument head design enabling field serviceability of lasers using interchangeable laser modules.

CGLs using the system have immediate feedback of how adjustments to the cleaning section affect surface cleanliness out of the cleaning section, or sometimes, seeing the adjustments have no effect on cleanliness. With an instrument head before the cleaning section, the incoming cold-rolled sheet can be monitored. The system allows cleaning section performance to be bench marked before and after significant changes: for example, changing brushing technology; electrolytic cleaning phase change or power protocols; evaluating new solution types or operating temperatures; etc.

For one CGL operator the continuous, online, surface cleanliness data has launched an Industry 4.0 project towards automating cleaning section control using artificial intelligence to evaluate the surface cleanliness data along with other inputs. The prospects of advancement in process control around cleaning are promising with many anecdotes and data to share.

In summary, this non-commercial paper will explain details about the benefits and challenges found by CGL operators using the surface cleanliness evaluation system by showing detailed data, plots, and explaining anecdotal use-cases from CGL operators who have implemented the system. A very brief, contextual overview about surface cleanliness will be included to make the session an applicable as possible; why cleanliness is important, key historical methods used to measure surface cleanliness – with pros & cons, along with some fundamentals of cleaning section troubleshooting.