Flow Length Calculation Tool

Calculation of Flow Length and Flow Length - Wall Thickness Diagrams

The achievable flow length in injection molding is a crucial factor for the selection of materials. Due to the complex influences between material properties, machine parameters and processing conditions, the flow length is not easy to predict. Simple material properties, like the MVR/MFI do not allow any precise calculation.


Material Data Center offers a flow length calculation module, which can help to solve these problems, using the relevant physical material characteristics (like viscosity-shear rate diagrams). In a few seconds the system is able to simulate the achievable flow length for a given constellation (for two specific geometries, spiral and circular disc) and even generates flow length - wall thickness diagrams. The relevant formulas are solved using the finite difference method, considering parameters like material properties, maximum pressure and injection volume as well as mold and melt temperature.


The flow length calculation can either be activated directly from the datasheet of any given material, or from the ToolBox module. Here the requested material can be selected comfortably from a pick list which contains only grades for which all necessary material properties are known. From here calculation can be started directly.


The calculation program will automatically take over the relevant material properties and make suggestions for the free parameters, like machine settings and flow geometry, which can be modified by the user.


The calculation results can be printed or converted into a comfortable pdf format.


Example for a calculation result pdf-file



  • The problem is calculated one-dimensional over the wall thickness. All effects in transverse direction, like heat flow, freezing) are neglected.
  • The thermal material properties of the melt are taken from CAMPUS, these are constant and not temperature dependent.
  • The viscosity properties are also taken from CAMPUS and approximated using the Carreau WLF model.
  • Melt temperature at the injection point and mold temperature are considered to be constant.
  • No heat transmission resistance between melt and mold surface.

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