Use Moldflow Analysis to Maximize Complex Injection Molding Outcomes

Posted by Al Timm on Oct 25, 2017 9:58:00 AM
Al Timm
Inspecting Moldflow Analysis

Moldflow analysis is a frequently used term in the injection molding industry but it is often poorly understood. The process uses a sophisticated computer program to analyze and predict the flow and cooling of plastic during all phases of the injection molding processSince there are different levels of analytical software available, selecting the right one for your project is as important as interpreting the data for successful results.

Moldflow Analysis Levels

Undertaking moldflow simulation and analysis during the design phase ensures higher-quality parts and optimizes cycle times and reduces the number of tooling trials. The level of analysis required depends on the complexity of the part and desired outcomes.

The most basic level of moldflow analysis includes a simulation of the fill and packing phases. This helps optimize gate location, gate sizes, balance runners and process conditions.

More advanced simulations compare runner systems, mold temperatures and can even predict fiber orientation. They provide critical information for predictions regarding more complex parts and processes, and help engineers properly gauge:

  • Shrink which is unavoidable in plastic, and generally occurs because of material structure (for example, semi-crystalline or amorphous), packing pressure and wall thickness. Engineers must be able to accurately estimate shrinkage to properly size the mold.
  • Warp that results from one of three sources: unbalanced mold cooling, fiber orientation and non-uniform shrinkage. Warpage analysis reveals the causes of warpage and where warpage will occur before the mold is built, allowing engineers the opportunity to optimize part design, mold design and processing parameters to minimize deformation before production starts.

Predictive Parameters and Better Results

Other key parameters that can be predicted through moldflow analysis are:

  • Processing conditions
  • Flow-induced shear stress
  • Weld line location
  • Air trap prediction
  • Sequential valve gauging
  • Cavity/part temperature differential
  • Coolant temperature

Because moldflow analysis identifies and mitigates potential problems related to these parameters before the mold is constructed, it reduces risk, improves quality and lowers overall production costs. With all of these benefits, you may be tempted to run moldflow analysis on all projects. However, in the case of extremely simple parts made from common materials, moldflow analysis may not be required or even be very beneficial. But, most projects with complex, high-tolerance parts that require precise dimensional stability are ideal for moldflow analysis and will realize the greatest advantage.

Compare More Than Cost

It's important to note that top-level moldflow analyses are expensive and require highly skilled personnel to run them and interpret their results, and not every supplier that claims to have the capability can actually deliver. That said, don’t make a moldflow decision based simply on cost. Work with an experienced injection molder like Kaysun to discuss the complex geometries, tight tolerances and other intricacies of your project to determine the best moldflow option for your needs.


For more information on improving manufacturability and quality while reducing costs, read our whitepaper Tight Tolerance is Critical for Top Quality and Superior Performance. Click the button below to download your free copy:

Tight Tolerance is Critical for Top Quality and Superior Performance

Topics: Injection Molding, Plastic Part Design, Technology