An Amcor employee was working on the extrusion wheel, attempting to fix an issue with the bottle weights and the pressure from the parison air. The employee completed the inspection/repair and began the start-up sequence. The parison did not feed properly. The employee went to correct the misload. The plastic then fell off to the side and the employee attempted to grab it but his right hand got caught in the side of the mold as it was closing. The employee's fingertip was amputated.