One of the keys to quality plastic injection moulded parts is an accurate mould that produces consistent pieces every time. But how do you ensure that is accomplished? That’s where testing the process via mould flow analysis (MFA) software comes in. Mould flow analysis can help you identify any issues with the mould cavity, material, or conditions before you start the process. In this blog, we’ll discuss everything about MFA including what it is, how it works, when it’s used, the components involved, and much more.

What is Mould Flow Analytics

Mould flow analysis is a technique that involves simulating an injection moulding cycle with a specific plastic. This is carried out with specialised software which simulates the design of the component and is an essential part of the plastic injection moulding process because how the molten plastic flows inside the mould significantly impacts how the finished product behaves. By opting for MFA before injection moulding, you may save time, money, and future issues.

The software used generates colour maps to show how the material will flow in the mould. It includes features including, but not limited to:

• Fill Time
• Ease of fill
• Results adviser
• Pressure profile
• Part and mould temperature profiles
• Shear rate
• Cooling time
• Weld lines
• Air traps
• Sink marks
• Frozen layer fraction
• Clamp force
• Cycle time
• Volumetric shrinkage
• Displacement (part warpage)
• Part insert overmoulding
• Multi-shot overmoulding
• Fiber orientation analysis
• Valve gates
• Venting analysis
• Mould inserts
• Gas- or water-assisted injection moulding
• Co-injection moulding
• Birefringence
• Reaction injection moulding
• Conformal cooling analysis

This is a thorough and hands-on process that is carried out by professionals in the plastic injection moulding process.

How Does Mould Flow Analysis Work?

The process begins by importing the customer’s finished component model into the software and selecting the appropriate polymer from the database. Next, the fill/feed/gate position and size is selected. This is important for the software to understand where, and at what volume, the material can enter the cavity. Details about the injection moulding press must also be provided, including injection pressure and capacity. Different machines have different capabilities, so what works for one press may not be suitable for a smaller one

The simulation gives a detailed representation of the flow pattern and will highlight if the part can be successfully filled based on the specific parameters. However, any other conclusions will need to be deducted from the results of the analysis.

Key Components of Mould Flow Analysis

The mould flow analysis involves key components, including:

Filling Analysis

Filling analysis analyses how molten plastic fills the cavity, and predicts flow patterns, velocity, and pressure distribution. This component helps to optimise the gate placement (where the molten plastic enters the cavity) and runner design (the channels that carry molten plastic.

Packing and Holding Analysis

This component evaluates material shrinkage and pressure distribution to prevent sink marks, voids, and dimensional instability.

Cooling Analysis

Here, the software simulates temperature distribution throughout the mould and identifies hot spots and cooling inefficiencies that could lead to warpage in the finished product.

Warpage and Shrinkage Prediction

Mould flow analysis can assess part deformation and shrinkage rates after cooling. This can help designers modify the mould and process parameters to minimise defects.

Air Traps and Venting Analysis

This component involves detecting any area where air could be trapped, causing defects in the final product. This helps create a smooth material flow.

Weld Line and Knit Line Analysis

This component of mould flow analysis identifies where multiple flow fronts meet, forming weld lines. This evaluates any potential structural weakness or aesthetic issues.

Shear Stress and Viscosity Analysis

The software examines shear rates (how quickly layers of plastic slide past each other during the injection process) to prevent burn marks and material degradation.

Runner and Gate Optimisation

This component provides a heat map and gives an optimum position based on distance and mass.

Benefits of Mould Flow Analysis in Plastic Injection Moulding

MFA is a beneficial part of the injection moulding process as it ensures the parts produced are high-quality and free of defects. Here are some of the benefits of mould flow analysis:

Improved Part Quality

Mould flow analysis can identify any potential defects like warpage, sink marks, and air traps before the mould is even produced . Although these can be predicted without MFA, it helps give a more refined answer in a format that is easy to understand. This allows time for any amendments to be made to the mould and process parameters to ensure a high-quality, defect-free final product.

Cost Savings

MFA can identify   any potential issues before production. If issues are found, it can reduce the risk of defects that lead to expensive rework and modifications.

When is Mould Flow Analysis Needed?

Although mould flow analysis is an incredibly important step , it isn’t always required. Here are some of the factors that can affect whether mould flow analysis is required.

Product Geometry

The more complex a mould design is, the more you will benefit from mould flow analysis. When a design is intricate, it can be less predictable compared to a simple mould.

Tolerance Requirements

Ensuring tight tolerances in injection moulding depends on choosing the right material. High tolerance parts require low-shrinkage engineering polymers for more stable processing. Mould flow analysis can help achieve a stable size with higher shrinkage polymers.

Unusual Materials

Engineers know the fill patterns of standard materials, but there are some materials that they may not be familiar with that would benefit from mould flow analysis . For example, polymers with fillers such as glass or carbon fibre as can shrink unevenly due to the fibre orientation.

Looking For Quality Plastic Injection Moulding?

At Pentagon Plastics, we offer comprehensive plastic injection moulding services from the initial design to the development of the mould, tooling, production, and post-production support. We’re committed to delivering a service that exceeds expectations and producing quality parts that are consistent and to your specifications. To accomplish this, we use MFA software alongside a range of other cutting-edge tools and technology.

If you’re looking for a UK plastic manufacturer, we can help. Get in touch with us now to see what we can do for you.