Design of experiments (DOE) is a systematic approach used to plan, conduct, and analyze experiments in order to understand the relationship between factors (independent variables) and their effects on a response (dependent variable). It provides a structured methodology for exploring the effects of multiple variables simultaneously, rather than testing each variable individually, which can be time-consuming and less efficient.

Challenge

In an injection analysis design we face the following challenges:

• Injection molding involves numerous factors such as melt temperature, cavity pressure, mold design, cooling rates, and material properties. Managing and analyzing the interplay between these factors can be complex.
• Factors do not always act independently; their interactions can create unexpected results. Identifying and understanding these interactions requires careful planning and analysis.
• It is problematic to determine the extent to which each factor influences the results, so it may be questionable which ones would be worth modifying.
• It is difficult to determine which concept suits us the best.

Method, software used

Moldex3D, Finite Element Method (FEM), Design of Experiments (DOE)

Engineering solution

The Expert module offered by Moldex3D provides the opportunity to use design of experiments to examine the effects of injection molding parameters and determine the most suitable settings for us.

In this example, we investigate the effects of varying melt temperature, cooling time, and packing pressure on the output variables. We set three temperatures within the standard melt temperature range from the Moldex3D database. We select the cooling times based on the ideal cooling time determined by a previous analysis. The packing pressure is set to 40%, 60%, and 80% of the end of filling pressure.

To find the most suitable concept for us, we can specify conditions and assign weights to indicate the importance of each condition. In this example, we have considered flatness, maximum sprue pressure, and maximum clamping force, but there is also the option to include considerations for connector size, shear rates, volumetric shrinkage distribution, and other outputs.

Benefits

The Moldex3D Expert Module offers the following benefits to users:

• It runs simulations by varying numerous parameters.
• It determines the best concept based on the conditions we provide.
• It creates graphs to evaluate the impact of parameters on results, showing how much each parameter has influenced the outcome.
• It produces tables for better clarity and visibility of the results.
• It produces response sufrace graphs. On this graph, for example, flatness is illustrated as a function of packing pressure and cooling time.