Design and Modeling of a Dosing Unit in a Capsule-Filling Machine

This paper focuses on the design of a dosing unit in an automatic machine to fill capsules with pellets. We first define the design requirements and constraints, such as the end-effector trajectory, the overall maximum dimensions, the adoption of low-lubrication systems to minimize contamination risk, architecture simplicity, and washability. Through an initial feasibility study, we select the solution that best satisfies the goals. The kinematic and dynamic model of the dosing unit is built and validated by a multibody simulation. The numerical model is used to construct an iterative process for sizing the motors and the unit inner mechanisms, to optimize dimensions, reduce peak accelerations, and achieve the desired transmission ratio. Finite-Element Analysis is finally performed for the most critical components. The new dosing group is capable of high-speed operation with optimal dosing accuracy.