AbstractThe biomass extrusion process for making biomass briquettes or logs normally requires large amounts of energy to overcome the springback of the material and friction with the die surface. Also, the products readily expand and disintegrate because of the retention of internal stresses. In this study, tests on vibration-assisted compaction of biomass were performed as a method to reduce the energy requirement and to improve product quality. An experimental set-up was designed and manufactured by which vibration-assisted compaction was exerted on a die surface. Tests on compaction to form upgraded biomass logs with and without the assistance of vibration were conducted and compared. The results showed that the vibration applied on a die surface can reduce the compression energy requirements and improve product quality.