How injection molding simulation software helps you design better parts

How injection molding simulation software helps you design better parts

Injection molding simulation software is an important part of the IM workflow, allowing designers to assess the feasibility of their molds and moldings. This article looks at how it works.

What is injection molding?

Injection molding is a manufacturing process behind a huge number of manmade objects, from water bottles to automotive components.

It comprises several stages. First, a manufacturer must create a metal mold, which is usually split into two or more parts. An injection molding machine then fills the mold with molten plastic, which hardens within the mold to create a plastic part. Once hardened, the part is ejected from the mold, and the injection process is repeated.

To make high-quality molded parts, manufacturers need to know how the molten plastic will behave once it is injected into the mold, and how the finished part will perform once it is removed from the mold. Molds only work well when they’re designed a certain way, and different plastics behave in different ways.

One tool that manufacturers use to acquire such knowledge is simulation software. This software predicts what will happen during the injection molding process and ultimately allows manufacturers to tweak their mold design for a more favorable outcome.

Types of injection molding software

This article will focus on simulation software, but computers and software play an important role throughout the injection molding process, from design all the way through to quality control.

Injection molding software may include:

  • CAD software: Although not unique to injection molding, Computer-aided Design software is used to digitally design tooling and molded parts. Some CAD platforms contain extra features such as simulation or cost analysis.
  • Simulation software: For injection molding applications, simulation software can be used to predict behaviors such as fluid dynamics and mechanical stress, based on current designs for the molded parts.
  • Production software: Software is used during the injection molding process to control the injection molding machine. Tools may include production scheduling, raw material management and temperature control.
  • Monitoring/quality control software: Combined with a hardware input device like a camera or probe, inspection and quality control software can be used in the assessment of molded parts for quality assurance.

How injection molding simulation software works?

Injection molding simulation software is used to make better molded parts and reduce defects. It does this by digitally simulating virtually every aspect of the manufacturing process, from material flow to coolant distribution to shrinkage and warpage of the molded part.

Simulations may be based on user-defined data, such as the mold design, injection material cycle time, etc. However, feedback from the software will encourage the user to make changes to designs and parameters where necessary in order to improve performance when production begins.

Some simulation software incorporates CAD and other design features, while some packages are standalone.

Common features of IM simulation software include:

Warpage and shrinkage simulation

Molds are injected with molten plastic, which then cools and hardens to form a solid part. Parts shrink slightly as they cool, but if material in one part of the mold cools faster than another, the part may exhibit warpage and be unfit for use.

Warp analysis is a feature of simulation software that predicts how a part might warp and deform as it sets, and then recommends solutions to reduce the warpage.

Solutions may include changes in wall thickness or movement of gates and runners.

Gate placement

A gate is a gap in a mold where molten material enters. Incorrect gate placement can lead to part defects, but there are often areas of a part that are unsuitable for gate placement, for functional or aesthetic reasons.

Gate location analysis allows the user to see how certain gate locations will affect factors like flow rate, shrinkage and overall part success.

Most gate placement tools can recommend the ideal gate location based on predictive analysis and user preference.

Runner balance

Injection molding simulation software can be used to determine the placement and balance of runners, which are the thin channels that deliver the molten plastic to the mold.

Proper setup of runners ensures even filling of the cavity.

Used in conjunction with gate placement and other tools, a runner balance tool can be used to optimize runner setup.

Packing optimization

An important feature of IM simulation is determining an ideal ram speed and packing pressure for a molded part.

The ideal configuration depends on factors like mold shape and injection material, as well as the machinery itself.

Overmolding, co-injection and multi-barrel simulation

Advanced simulation software packages can simulate more complex operations like overmolding (molding onto a substrate), co-injection molding (injecting two materials into one mold) and multi-barrel molding (using multiple barrels to quickly fill a mold).

Analysis of these processes is more complicated as it takes into account a greater number of variables.

Benefits of using simulation software

IM simulation software provides numerous benefits that lead to better parts. Advantages include:

  • Eliminates errors and defects
  • Reduces undesirable effects like warpage and shrinkage
  • Improves efficiency and reduces cycle times for higher production rates
  • Solves problems before production, preventing costly mistakes
  • Allows for simulated testing of multiple thermoplastics with no wastage of real materials
  • Integrates with CAD suites to simplify design workflow
  • Runs multiple simulations at once
  • Generates reports for easy communication with team members, customers, etc.

Popular injection molding simulation software

Well-known IM simulation packages include Autodesk Moldflow, CoreTech Moldex3D, SOLIDWORKS Plastics, SIGMASOFT Virtual Molding and Vero VISI Flow.

3ERP has years of experience in rapid tooling and low-volume injection molding services. Contact us for a free quote today.