Product Changeover

Case II. Mill Start and Product Changeover

During mill startup and product changeover, process conditions are unstable and particle size distribution can vary significantly before the grinding circuit reaches steady operation. Traditional laboratory measurements are too slow to detect these rapid changes in real time, forcing operators to wait for delayed results before making process adjustments. As a result, large quantities of material are often produced outside specification and must be recycled or discarded.

Real-time inline PSD monitoring allows operators to immediately observe how the product changes during startup or recipe transitions. The system continuously tracks particle size evolution and instantly detects when the process enters a stable operating regime. Instead of relying on delayed laboratory feedback, operators receive live PSD information directly from the process, allowing much faster optimisation of separator speed, mill conditions, and process parameters.

By reducing the time required to achieve stable operation, inline PSD measurement significantly decreases material waste during every startup and product changeover. Plants can minimise contamination between products, reduce off-spec production, and avoid unnecessary energy consumption caused by prolonged unstable grinding conditions. Faster stabilisation also improves operational flexibility, enabling more efficient production scheduling and quicker transitions between different product grades.

“The first pancake is always lumpy” is a simple analogy for mill startup and product changeover. Just as the first pancake in a pan is rarely perfect, the grinding circuit initially produces unstable and inconsistent particle size until steady operating conditions are reached. Real-time inline PSD monitoring helps minimise this unstable period, reducing waste, contamination, and off-spec product during every startup and transition.

The ROI of inline PSD monitoring is often achieved simply by reducing the amount of off-spec material produced while waiting for delayed laboratory results. During startup or product changeover, valuable material may continue to be manufactured outside specification for many minutes before operators receive lab feedback and correct the process. Real-time Xoptix monitoring eliminates this delay, allowing immediate process adjustment and significantly reducing wasted product. In many applications, the value of saved material alone can justify the investment in the Xoptix system within a relatively short period of operation.

A customer in Belgium calculated ROI based solely on reduced product losses during product changeovers, achieving estimated savings of 365,000 $/year and an ROI of less than 3 months.