Shrink Index-Based Timber Classification and Finger Joint Production

Inadequate length of sawn timber material is also reported to be a limiting factor for fully utilization of timbers. Finger joint, a method that connects two small pieces of timber together is identified as a sound technique to minimize the wastage. At the finger joint production process, different timber species have to be bonded together for making finger-jointed mixed boards. When mixing different timber species together, they should be similarly matching timber pieces based on the dimensional effects. The present study focuses on developing a classification system for 32 selected clear timber species, based on their shrinkage effect in three different environmental conditions, to assist the finger joint technique. Three climatic factors were identified through an analysis to determine the shrink index for the selected timber species. The shrink index values were grouped into five classes, as very low, low, medium, high and very high. Cluster analysis was used for grouping the species with similar shrinkage properties. Pearson correlation of Shrink Index and Density was -0.134. So, there is no significant relationship between the shrink index and density (P > 0.05).