MOULD DESIGN
Design principles for injection moulds, gate systems, cooling channels, and ejection mechanisms.
“The mould is where polymer science meets mechanical engineering. Getting it right before cutting steel saves everything.”
— Mould Design · PolymerHub
12 Lessons
Multi-Cavity Runner Balancing: Pressure Drop Equations, Rheological Balancing & Sequential Gating
Multi-cavity runner hydraulic pressure drop modeling via Hagen-Poiseuille, progressive branch sizing, shear-induced thermal runner imbalances, and MeltFlipper solutions.
Hot Runner Valve Gating Mechanics, Sequential Injection & Thermal Control
Hot runner manifold design, thermal expansion growth allowance formulas, pneumatic vs hydraulic valve pin actuation, and sequential valve gating timing for cosmetic weld-line elimination.
Undercut Release Mechanics: Side Cores, Angular Cam Pins, Slides & Lifters
Mechanical tool kinematics for external and internal undercuts, angle pin stroke calculations, side slide travel, heel locking blocks, and internal lifters.
Gate Design in Injection Moulds: Types, Location & Shear Kinetics
Learn how gate design controls where and how plastic enters a mould cavity — one of the most critical decisions affecting part quality, cycle time, and appearance.
Cooling System Design in Moulds: Heat Transfer Kinetics, Turbulent Channels & Conformal Lines
Learn how mould cooling channel design controls cycle time, part quality, and warpage — the single biggest lever for injection moulding productivity.
Ejection Systems in Moulds: Mechanics, Pin/Sleeve Actuation & Stripper Mechanics
Understand how moulded parts are safely removed from the mould without damage, covering ejector pin design, stripper plates, and air-assisted ejection for thin-wall and deep-draw parts.
Injection Mould Runner Systems, Gate Design & Feed Balancing
Learn how runner systems deliver molten plastic from the machine nozzle to every cavity in a multi-cavity mould — and why balanced runner design is essential for consistent part quality across all cavities.
Draft Angles & Volumetric Shrinkage Allowance in Injection Mould Design
Master two of the most fundamental dimensional design rules in mould making — draft angles that allow easy part release, and shrinkage allowance that ensures the final cooled part matches the intended dimensions.
Mould Steel Metallurgy, Heat Treatment & International Surface Finish Standards
Learn how to select the right tool steel for a mould based on production volume and part requirements, and how surface finish — from mirror polish to textured grain — is achieved and specified.
Hot Runner Systems — Design & Thermal Management
Hot runner manifold design, valve gate control, hot-drop thermal isolation, balanced flow channels, and prevention of thermal degradation.
Conformal Cooling — Design Principles & Additive Manufacturing
Design of conformal cooling channels following mold contours, 3D metal printing (DMLS), cooling efficiency improvements, and cycle time reductions.
Mold Flow Simulation (CAE) — Using Moldex3D & Moldflow
Finite element mesh generation, simulation of fill, pack, cool, and warp phases, gate placement optimization, and weld line prediction.
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