Statistical Process Control is a good way to check, but more-over control your product quality, and reduce the amount of complaints and overdosing of formaldehyde, and avoid caking and dust in the warehouse. 

Typically one wants to do quality control on the Size Guide Number (SGN) and Uniformity Index (UI), because these parameters determine how ones fluid bed granulation or prilling plant is running. One can also opt to apply Statistical Process Control on the load-out product, to enable a product certification and happy customers...More information