Multibody dynamic analysis of a packaging machine sealing head

Abstract

The sealing head of a packaging machine is the area where the cross sealing or welding of the packages is carried out. Sealing is done by exerting pressure between two hot jaws, a process called heat sealing. For these packages to be completely hermetic, the sealing must be perfect, which is achieved by means of a uniform pressure distribution on the contact surfaces of the jaws. In this article, a multibody dynamic analysis (MBD) of a sealing head has been carried out to determine the pressure distribution between the jaws. Due to the design of the head, it is essential to consider the stiffness of some components. A MBD model has been generated considering flexible bodies, with Altair’s HyperWorks software. The technique used by the software to generate flexible bodies is called Component Mode Synthesis (CMS) and consists of reducing a Finite Element Method (FEM) model of an elastic body to the degrees of freedom of the interface nodes and a set of normal modes, i.e. from a nodal model to a modal one. With this approach, it is possible to calculate the forces and deformations generated during the sealing process and precisely determine the pressure distribution, and thus the quality of said sealing. The entire methodology is validated by comparing the results obtained by simulation with FEM simulations and experimental data from tests.