Injection Moulding Principles
Defective plastic parts are often only found late in the day and after significant investment of time and money. Our well-established course will help you develop an understanding of the causes of part defects and how to avoid them. Common plastic part defects will be explored and solutions developed, enabling attendees to design plastic parts with confidence.
Description
Design choices such as thickness, ribs, gating, draft, and material selection can significantly affect moulding outcomes. Proper thickness ensures uniform cooling and reduces the risk of defects. Ribs enhance structural integrity without adding excessive material. Gating influences flow patterns and part quality, while draft angles facilitate easy ejection from the mould. Material selection impacts mechanical properties, thermal stability, processing, and anisotropic properties, which affect the directional strength and performance of the final product.
This one-day course combines lecture content and guided workshops to enable an understanding of how these factors influence part quality, manufacturability, and performance. The course will also introduce the common application of Finite Element Analysis (FEA) tools to identify issues early in the design cycle.
Agenda
1 day course with guided workshops:
Module 1 – Plastic Flow in Injection Moulding
Understand how the viscosity and temperature of polymers affect flow behaviour patterns. Learn about heat transfer within the mould thermal management and cooling systems. Examine how pressure drives flow of molten plastic through the mould.
Module 2 – Polymer Materials
Explore the differences between amorphous and semi-crystalline polymers, and how they affect processing and performance. Understand how fibre reinforcement enhances polymer properties, including strength, stiffness, and durability. Examine criteria for selecting polymers for specific applications, considering mechanical properties, thermal stability, chemical resistance, sustainability, and cost.
Module 3 – Shrinkage & Warpage
Understand causes and mitigation strategies for shrinkage in moulded parts. Learn why packing pressure can control shrinkage. Examine factors contributing to warpage and strategies to minimise it through material selection, mould design, and processing conditions.
Module 4 – Tooling & Processing
Learn the principles of gate placement to ensure balanced flow and minimise defects. Understand how gate location affects part quality, filling patterns, and cycle time. Explore the differences between hot and cold runner systems, including their advantages and applications. Learn how to select and design runner systems to improve efficiency and reduce waste.
Module 5 – Analysis & Simulation
When to simulate? Understand the importance of simulation in optimising design and improving part quality. Explore the use of mould flow analysis engineering tools. Learn strategies to predict and mitigate warpage and distortion using simulation data.
Module 6 – Failures in Service
Identify common causes of failures in injection moulded parts, including material defects and processing errors. Understand how residual stresses develop and their impact on part performance. Learn about the effects of mechanical properties and shear degradation on part durability. Explore the phenomenon of creep and its implications for long-term part stability.