Additional sources of changing shrinkage rates during kiln drying

This paper emphasizes the established need for a stress based kiln control system. It refers to 1) the work which verified that the initial shrinkage rate changes within a board are the result of reduced stress levels and 2) the new statistical method short/long-term slope comparison method used to detect slope changes. The paper continues by giving the explanation for the additional shrinkage slope changes as the equilibrium moisture content cha nges during fan reversal and kiln schedule advancements. The kiln schedule advancements can cause both shrinkage and swelling. Reduced drying rate res ulting in reduced shrinkage rate explains other changes. A stress based aut omated kiln control system is conceptually possible with 1) shrinkage rate changes understood and 2) a production useful statistical method to detect these changes.