Experimental design for optimization of paper machine opacity

The goal of our study was to optimize the paper machine's opacity without adding any chemical products (clay, TiO2). We wanted to know which factors were affecting the opacity and the extent of their impact. We choose 6 factors that we could control and change on the paper machine. The level of these factors was chosen with the restrictions imposed by the production staff We took the minimum and the maximum fur each factor taking into account the customers' reject limits. The first trial plan gave us the chance to select 3 factors that had the most influence on the opacity. On the basis of these factors, we did a new vial plan to understand the possible interactions between these 3 factors. The results gave us a mathematical model which could be used to predict the opacity and eventually control it.