Design and Analysis of the Shaft for a Plastic Waste Shredder with a Dual-Stage Cutting Process

Abstract

The accumulation of polymer waste represents a profound ecological crisis. According to the National Waste Management Information System (2023), plastic waste constitutes 19.2% of Indonesia's total waste stream. Mechanical recycling through industrial shredders is indispensable, wherein the rotary shaft functions as the vital power transmission element subjected to torsional loading. This research designs an optimal rotary shaft for a plastic shredder using a dual-cutting mechanism and evaluates its mechanical integrity using AISI 1045 cold-drawn steel. The methodology integrates theoretical calculations with Finite Element Analysis (FEA). Operating parameters are based on a 3 HP motor with a reduction output of 1,440 rpm, yielding a working torque of 10.17 N·m. Analytical evaluations established a minimum required shaft diameter of 14.37 mm, standardized to 15 mm to guarantee rigidity. Static simulations executed in SolidWorks Premium 2021 demonstrated a maximum Von Mises stress of 4.332 MPa, well beneath the yield strength of 530 MPa. The maximum displacement was 0.0872 mm, with a minimum Factor of Safety of 3.4. These results substantiate that the shaft possesses exceptional structural integrity for continuous recycling operations.