Case Study: Optimizing a Press Moulding Process - A324

 

Case Study: Optimizing a Press Moulding Process
Perspectives article
Document Type	Article
Document Identifier	324
Themes	Thermal management
Tags	Cure and crystallization Process modelling Thermoset cure kinetics Cure cycle optimization
Prerequisites	Compression moulding Hot press Thermogravimetric Analyzer (TGA) Degree of cure Heat of reaction Flow and consolidation management Reinforcement properties
Webinar Date July 27, 2022

Introduction

Many of our previous webinars have introduced knowledge, theories, and background information on composite materials. How do we put these into practice and use them to make engineering decisions to obtain our desired outcome?

In this webinar we will take a thorough look at a case study on the optimization of a thermoset prepreg press moulding process that was optimized to cut the processing time in half by simply adjusting processing parameters. We will explain the theory and practice behind engineering tools used and decisions made throughout the study. The focus will be on material characterization, process simulation, microscopy, mechanical testing, and process verification.

Content discussed in the webinar is linked to the Knowledge in Practice Centre (KPC), allowing users to access this and other content in a consistent and coherent manner.

Presenter

Dr. Casey Keulen
Assistant Professor of Teaching, Department of Materials Engineering, The University of British Columbia
Director, CKN Knowledge in Practice Centre

Webinar slides

Webinar slides available by clicking on the icon below

Additional information for select chapters

Chapter	Chapter Title	Links to related information in the Knowledge in Practice Centre
1	Welcome & introductions	N/A
2	Knowledge in Practice Centre	Home - A1 AIM Events - Webinars - A115
3	Overview	Case Study: Optimizing a Press Moulding Process - A324
4	Press Moulding Processing: Overview	Compression moulding - A302 Hot press - A176
5	Press Moulding Processing: Common Applications	Compression moulding - A302 Hot press - A176
6	Case Study: Setting the Scene	Systems approach to composite materials - A230
7	KPC: Optimizing a cure cycle	Optimizing a cure cycle for improved production rates - P144
8	Case Study: Summary of Workflow	Future Content
9	Material Characterization: Thermal stability	Thermogravimetric Analyzer (TGA) - A329
10	Material Characterization: Cure kinetics	Degree of cure - A104 Heat of reaction - A114
11	Material Characterization: Consolidation	Flow and consolidation management - A158 How to measure reinforcement content (and corresponding matrix content) - M109 Reinforcement properties - A213
12	Material Characterization: Processing temperature	Future Content
13	Material Characterization: Part DOC	Degree of cure - A104
14	Model Validation: Confirm expected DOC	Future Content
15	Model Validation: Simulate existing process	Future Content
16	Process Optimization: Cure optimization	Future Content
17	Process Optimization: Post-cure optimization	Future Content
18	Optimized Process Validation	Flow and consolidation management - A158 How to measure reinforcement content (and corresponding matrix content) - M109 Reinforcement properties - A213 Degree of cure - A104
19	Optimized Process Validation: Dimensional specs.	Residual stress and dimensional control management (RSDM) - A165
20	Optimized Process Validation: Mechanical prop.	Composite materials engineering webinar session 12 - Testing - A131 Effect of cure on mechanical properties of a composite (Part 1 of 2) - A319 Effect of cure on mechanical properties of a composite (Part 2 of 2) - A320 Residual stress and dimensional control management (RSDM) - A165
21	Summary & wrap-up	N/A
22	Q&A	N/A

Related pages

Page type	Links
Introduction to Composites Articles
Foundational Knowledge Articles	Conduction - A118 Convection - A106 Glass transition temperature (Tg) - A210 Heat of reaction - A114 Viscosity (resin) - A203
Foundational Knowledge Method Documents
Foundational Knowledge Worked Examples
Systems Knowledge Articles
Systems Knowledge Method Documents
Systems Knowledge Worked Examples
Systems Catalogue Articles
Systems Catalogue Objects – Material
Systems Catalogue Objects – Shape
Systems Catalogue Objects – Tooling and consumables
Systems Catalogue Objects – Equipment	Rheometer - A357
Practice Documents	Increasing throughput by curing parts simultaneously - P143 Optimizing a cure cycle for improved production rates - P144 Practice for developing a thermal transformation process step - P105
Case Studies	Troubleshooting of room temperature processes for large recreational and industrial parts - C100
Perspectives Articles	Case Study: Optimizing a Press Moulding Process - A324 Composites Process Simulation: A Review of the State of the Art for Product Development - A283 Dr. Anoush Poursartip's cdmHUB global composites expert webinar - A136 Fabric Forming: how it affects design and processing, and how simulation can address this - A310 Interview with Prof. Kevin Potter - A134 Simulation models for rapid liquid composite molding - A333.0 Understanding Polyester Resin Processing: The Effect of Ambient Temperature on the Final Part - A286

About	Help

In the context of knowledge in practice, knowledge refers to the systematic use of science based knowledge in composites manufacturing practice.

There is a distinction between experience based knowledge and science based knowledge:

• Experience based knowledge (‘know-how’) is an understanding of potential outcomes and their relationships that is founded on pragmatism and experience accumulated over time in individual programs, companies and in the industry more broadly.
• Science based knowledge (‘know-why’) is an understanding of potential outcomes and their relationships, based on the important processing physics, that is mature enough to be codified using the appropriate governing laws and constitutive equations.

Engineered materials (designed to have specific properties) made from two or more constituent materials with different physical or chemical properties. The constituents remain separate and distinct on a macroscopic level within the finished structure.

Any manufacturing and/or decision making activity that occurs during any stage of the development design cycle (e.g. conceptual design to production).

In the context of Knowledge in Practice, practice refers to the systematic use of science based knowledge to reduce composites manufacturing risk, cost, and development time.

Thermosets are a class of polymer that undergo polymerization and crosslinking during curing with the aid of a hardening agent and heating or promoter. Initially they behave like a viscous fluid. During curing, they change from viscous fluid to rubbery gel (viscoelastic material) and finally glassy solid.

If heated after curing, initially they become soft and rubbery at high temperatures. If further heated, they do not melt but decompose (burn)

Comes in two parts: part A (resin) and B (hardener). When mixed, curing reaction starts and is not reversible.

Examples include epoxy or polyester.

Pre-impregnated (prepreg) material refers to fibre that is already combined with resin. It is the most common material form used in aerospace.

During prepreg production, (e.g. fibres are run through a resin bath), prepreg is heated and partially cured to B Stage (< 5 % degree of cure). Thermoset prepregs (e.g. epoxy prepreg) have to be kept in a freezer at around -20 °C. At room temperature, the epoxy starts to cure.

The use of multiphysics models to predict the outcome of real-world scenarios. May be analytical (closed form, "hand calculations") or computational (implementation on computers is required due to the large number of calculations involved. e.g. finite element method, finite difference method)

Most often in composite materials engineering, simulation refers to either:

• Process simulation (predicting manufacturing outcomes, or the inverse problem of predicting manufacturing parameters to achieve a desired outcome), or
• Performance simulation (predicting the stiffness/strength/suitability of a structure, or the inverse problem of the material properties and dimensional requirements to achieve a desired stiffness/strength/suitability of a structure)

(same as "Modelling")

With regards to modelling & simulation, verification confirms the implementation of a computational model to ensure that it represents the mathematical model and equations used to describe it (requirements are met).