Modeling a Manufacturing Process of Plastics Films for Packaging | AIChE

Modeling a Manufacturing Process of Plastics Films for Packaging


Talwar, R. B. - Presenter, Sant Longowal Institute of Engineering and Technology, Longowal

Modeling a polymer process in order to better understand the system, to solve an existing problem or perhaps even improve the manufacturing process itself. Furthermore, a model can be used to optimize a given process or properties of the final product. In order to model or simulate a process we need to derive the equations that govern or represent the physical process. Before we solve the polymer melt process governing equations we must first simplify them by using a set of assumptions. These assumptions can be geometric simplifications, boundary conditions, initial conditions, physical assumptions, such as assuming isothermal or non-isothermal systems, anisotropic materials, as well as models, such as non- Newtonian, linear or nonlinear viscoelastic, shear thinning, or others.

These steps on modeling are:

  • Define the scope of the problem and the goals that are to be achieved.
  • Sketch the system and define parameters such as geometric parameters (dimensions- diameter, channel depth, channel width and helix angle), processing conditions (such as temperature, pressure, rotational speed of the screw), material parameters (such as viscosity and melting temperature) and boundary conditions.
  • Write down the general governing equations that govern the variables in the process, such as mass, energy and momentum balance equations.
  • Introduce the constitutive equations that relate the problem’s variables.
  • State the assumptions and reduce the governing equations using these assumptions
  • Scale the variable and governing equations.
  • Solve the equation and plot results.

However, the pilot system is too small to be feasible, and must therefore be scaled up for production.