Key Factors in a Reliable Plastics Injection Molding Simulation Report

I have written in a prior post about the key factors necessary in a plastics injection molding optimization analyst.  Now, I would like to discuss the importance of a skillfully assembled simulation report.  Jennifer Schmidt spoke of the key ingredients of a trustworthy injection molding simulation report in her talk at the Plastics Technology Molding 2021 conference. In this brief, I will discuss the valuable information she provided and add additional feedback.  If you want a successful outcome for your tool, these key components are essential to consider.


Injection Molding simulation software


  • What version is being used and is the software up to date? Look for signs that the analyst is using an older version of software which will alter the results on the report, and ultimately the floor results.

Typically, the output file(s) of the software contain the release version of the software.  It might not be the absolute latest release of the software, but is should be a proven release which is typically a year old or less.

Mesh quality for injection molding

2. Type of Mesh used: Consider the type of mesh that used for the part and the runner.

  • Is the mesh type appropriate for the part geometry?
  • Is it precise enough in critical areas to capture important details?
  • Is the correct technology being used for the part geometry/runner combination, i.e. midplane, Dual-Domain, 3D or a specialty mesh used?
  • Will the report allow access to display the mesh?
  • Does the filling animation, weld lines and sink marks reveal insights into the mesh quality?

Consider: Simulations of the same part with the same material and same mesh density, but different mesh types for the part and runner, may produce different results for pressure at the fill-to-pack switchover point, which could make quite a difference in what occurs in an actual molding environment.

There are many factors to consider and only a seasoned user with the proper education in the software will be able to make these determinations in order to provide the best analytical outcome.

Material Data for injection molding


3. Material Data: An accurate molding prediction requires good material data.

  • What was the material data in the simulation based on?
  • Was data on the actual material available?
  • Was the data a substitute?-a resin of the same generic family but has a different molecular weight, flow characteristics, and different level of fillers, reinforcements or other additives used in the actual molding?
  • What was the level of material characterization? How much data was available? How recently was that data generated? Has the formulation changed?

There are many ways for the material data to be manipulated.  It is critical that the user understand the data and how to identify if the data has been changed to suit the needs of the project.  Unless the user is skilled in material data characterization, changing any component of the material data can be very dangerous as it will affect the outcome of the simulation.

4. Credibility of predictions:

  • What was modeled?
  • What analysis sequences were run?
  • Are there inputs for the results that can be reviewed?
  • Is there data on time to freeze, volumetric shrinkage, cooling, etc?

There are many criteria to consider with regards to credibility.  The analyst must have a clear understanding of the objective of the project so the analytical approach addresses the concerns and outcome of the project.

Credibility of predictions in injection molding


5. Processing Conditions- Beware of default settings

  • What processing conditions were used?- fill time, mold temp, melt temp, packing pressure, packing time, cooling?
  • How were the processing conditions determined?

It is rare that the default settings apply to any project.  There are a host of settings that must be addressed in order to have an accurate prediction.  Default settings can actually cause the software predictions to be less accurate.

Is your injection molding analyst qualified?

6. The Analyst: Who is the Analyst?

  • Are they certified, experienced, knowledgeable about the Software? Polymers? Processing Conditions?
  • What is the level of their experience or plastics background?
  • How often do they perform similar simulations?

The skillset of the analyst is probably the most important factor with regards to the usage of plastics injection molding analytical software.  Simulation software requires knowledge in polymers, chemistry, metallurgy, part design, tool design, injection molding processing, design of experiments (DOE), heat transfer, just to name a few.  Any information that the analysis does not know will detract from the overall quality and outcome of the project.  When creating a simulation report, having a skilled, knowledgeable and qualified analyst is the key component that will produce the desired result for your project.

Molding simulation has changed the culture of injection molding by saving time and money on ‘trial and error’ mold development and rework. However, it is necessary to have skilled professionals accurately manage the software and interpret results with a critical eye.

Bozilla Corporation’s Injection molding Team has over 20 years of experience analytically and on the floor.  We specialize in optimization, consulting, engineering, troubleshooting and Autodesk Moldflow Training. Additionally, our plastics engineers have a full understanding of polymers and how they influence an injection molded part. Your success is our success and we focus on meeting the goals and timelines of our customers.

Contact Bozilla Corporation today and let’s discuss how we can successfully contribute to your project!, 800-942-0742,