Moldflow Analysis for PET Preform Moulds: How Simulation Reduces Defects and Development Cost
Before a single gram of steel is machined, Hexamech uses injection moulding simulation to validate every critical aspect of a preform mould design. This is how problems are caught at screen — not on the production floor.
What Is Moldflow and Why Does It Matter?
Moldflow is a finite element analysis (FEA) software used to simulate the injection moulding process before any physical mould is built. It models melt flow, heat transfer, pressure distribution, residual stress, and warpage across the entire mould system — including the hot runner, cavities, and cooling circuits.
For PET preform moulds, simulation is not a luxury — it is a necessity. The combination of high cavity counts, thin walls, tight IV and AA requirements, and short cycle times means that a design error discovered on the production floor costs orders of magnitude more than one caught in simulation.
Relative cost multiplier of discovering the same defect at different project stages
What Moldflow Analyses in a PET Preform Mould
| Analysis Type | What It Shows | Why It Matters for PET Preforms |
|---|---|---|
| Fill Analysis | Melt flow front progression; fill time; short-shot risk | Ensures all cavities fill simultaneously at balanced pressure |
| Cooling Analysis | Temperature distribution; cooling time; hot spots | Identifies crystallisation risk zones and uneven cooling |
| Pressure Analysis | Injection pressure requirements; pressure at gate | Validates machine selection; checks gate geometry sizing |
| Warp Analysis | Post-ejection deformation prediction | Validates preform dimensional stability; closure compatibility |
| Residual Stress | Frozen-in stress distribution | Predicts stress whitening and environmental stress cracking risk |
| IV / Degradation | Thermal history of melt; shear rate at gate | Predicts AA generation; validates gate geometry for AA targets |
How Hexamech Uses Moldflow in Every Project
Customer Brief
Resin grade, IV, application, cavity count, cycle time target
Initial Design
Manifold layout, gate position, core/cavity geometry
Simulation
Fill, cool, warp, pressure, IV degradation — all validated
Optimise
Gate geometry, cooling layout, runner balance — refined
Manufacture
Steel machined to validated design — right first time
No Hexamech preform mould design proceeds to machining without Moldflow sign-off. The simulation report is part of the project documentation — available to the customer as evidence of validated design. This is the engineering discipline that separates a precision mould manufacturer from a commodity toolshop.
Validated Design Before Steel Is Cut
Every Hexamech preform mould project includes Moldflow simulation. Your mould design is proven on screen before it is manufactured.
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