The objective of this study was to develop a detailed understanding of the roles and effects of the screw elements in the granule formation along the length of barrel in the twin screw granulator (TSG) by incremental addition of the elements in the screw configuration. The number of kneading and conveying elements in the screw configuration, liquid to solid ratios (L/S) and screw speeds were varied while studying their effects on the mechanism of granule formation and the granule attributes (size, shape and structure). In order to study the granule formation mechanism, the length of TSG barrel was divided into 10 Parts. This was done to mimic and understand the actual granulation process that occurs in the individual Parts (sections) when total barrel length (cumulative length of all 10 Parts) comprising both conveying and kneading zones in the screw configuration is used. Part-1 consisted two long pitch conveying elements (LPCE) followed by four short pitch conveying elements (SPCE). Part-2 consisted of two kneading elements (ICE) placed at the end of the granulator after 4SPCE. Similarly, Part-3 to Part-7 subsequently consisted 4, 6, 8,10 and 12KE. In Part-8, 2SPCE were placed next to 12KE which is named as 12KE + 2SPCE. Same thing was repeated for Part 9 with 4SPCE and Part-10 with 6SPCE. In a separate experiment, last 4SPCE in Part-10 were replaced by 2LPCE to study the effect of increase in the screw channel width on the granule size and structure. It was found that the granules became bigger in size, elongated and denser with increasing number of KE (Part-2 to Part-7) due to increase in shear and compaction forces acting on them. The influence is more evident at higher L/S. However, the presence of SPCE in addition to the KE (Part-8 to Part-10) reduced the size and elongation of granules due to the shearing and cutting action of SPCE. The granule formation and growth in the TSG was found to be the function of the type and number of elements in the screw configuration and the L/S. Presence of 2LPCE at the end of the screw configuration resulted in an increase in the granule size and structural voids due to the coalescence or re-agglomeration of granules. (C) 2016 Institution of Chemical Engineers. Published by Elsevier B.V. All rights reserved.