Composite materials engineering webinar session 6 - Manufacturing processes - Prepreg processing - A125

 

Composite materials engineering webinar session 6 - Manufacturing processes - Prepreg processing
Perspectives article
Document Type	Article
Document Identifier	125
Tags	Deposition Prepreg
Webinar Date July 21, 2020

Introduction

This session provides an introduction and overview of prepreg materials which are composed of fiber and partially cured resin that is combined at a specific, tightly controlled ratio. It is the most common form of material used in aerospace and is quite common for sports equipment. This session goes into more detail on prepreg materials and the processes used to manufacture parts with them.

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	Overview of Webinar Series	Composite materials engineering webinar series - A119
3	What is Prepreg?	Future content
4	Example: Prepreg material label	N/A
5	Converting from weight fraction to volume fraction	Future content
6	Calculating the thickness of an individual ply	Future content
7	Manufacturing process: Solvated prepreg	N/A
8	Manufacturing process: Hot melt prepreg	N/A
9	Deconstructed prepreg appearance (after burn-off)	N/A
10	Prepreg internal structure	Future content
11	Prepreg internal structure: Resin rich & dry areas	Future content
12	Prepreg internal structure: CT image	N/A
13	Interlayer toughened prepregs	Future content
14	Out of autoclave (OoA) prepreg	Future content
15	What happens to prepreg during cure	Future content
16	Viscosity and Modulus development during cure	Cure of thermosetting polymers - A162 Polymer properties - A212
17	Video of resin flow in a prepreg	N/A
18	Impregnation mechanisms and resin flow	Future content
19	Sources and sinks of porosity	Future content
20	Different types of porosity	Future content
21	Porosity in out of autoclave prepregs	Future content
22	Storage and handling of prepreg	Future content
23	Controlling moisture during storage and handling	Future content
24	Recieving quality inspection techniques	Future content
25	Properties that affect prepreg material deposition	Future content
26	Material deposition of prepreg: Hand layup	Future content
27	Material deposition of prepreg: Hand layup (OoA)	Future content
28	Dubulking	Future content
29	Comparison of uncompacted and compacted fibre-bed	Future content
30	Progression of debulking through time	Future content
31	Resin flow during debulk	Future content
32	Material deposition of prepreg: ATL/AFP	Future content
33	ATL/AFP: Material coverage considerations	Future content
34	ATL/AFP: Laps and gaps	Future content
35	ATL/AFP: Fibre misalignment	Future content
36	Material deposition of prepre: Drape forming	Future content
37	Drape forming: Bending of uncured plies	Future content
38	Drape forming: Common Defects	Future content
39	Wrap-up	N/A
40	Q&A	N/A

Related pages

Page type	Links
Introduction to Composites Articles
Foundational Knowledge Articles
Foundational Knowledge Method Documents	How to measure gel time - M101 How to measure reinforcement content (and corresponding matrix content) - M109
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
Practice Documents	Debulking - P167 Practice for Developing a Deposition Step - P157
Case Studies	Cost Comparison Study of a GFRP Leisure Boat Hull Manufacturing Method; Spray Up vs Resin Infusion - C115 Optimizing Cost vs Weight for Low Production Volume Parts - C112
Perspectives Articles	Composite materials engineering webinar session 5 - Manufacturing processes - Introduction - A124 Composite materials engineering webinar session 6 - Manufacturing processes - Prepreg processing - A125 Composite materials engineering webinar session 7 - Manufacturing processes - Liquid composite moulding - A126 Fabric Forming: how it affects design and processing, and how simulation can address this - A310 Fibre Architecture: Availability, pros and cons, and selection for my application - A309 Pultrusion of Thermoplastic Composites - A334

About	Help

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.

For polymer matrix composites (PMCs), resin refers to the matrix; the continuous material phase that binds the reinforcement together, maintains shape, and transfers load. Resins are divided into two main groups: thermosets and thermoplastics.

Weight fraction of either matrix or fibres with respect to total composite weight (matrix + fibre).

Volume fraction of either matrix or fibres with respect to total composite volume (matrix + fibre).

The act of combining reinforcement fibre, resin to shape on a mould (tool).

There are three main methods to combine resin and fibre to deposit onto a tool (i.e. material deposition):

• Wet Processes: Mixing liquid resin and dry fibre directly in the mould, e.g. Wet Compression Moulding process for parts in BMW 7 series
• Liquid Composite Moulding (LCM) processes: Infusing dry fabric with resin using a pressure gradient, e.g. High Pressure Resin Transfer Moulding process (HP RTM) for parts in BMW i3
• Prepreg Processes: Laying up using prepreg where resin and fibre are already combined, e.g. Automated Tape Laying (ATL) process for some of the parts in Boeing 787.