Prepreg Technology for Out of Processing

Prepreg Techno
Autoclave (
Proce

Presen

David B
Senior Applied

ology for Out of
(OOA) Cure
essing

nted by:

Bashford
d R&D Engineer

ACG – Experience in Epoxy

Advanced Composites Gr
supplying prepreg system

• LTM® (Low Temperature Mould
– Initial cure at 40°C - 80°C, b
– Tg up to 180°C after post-cu

• VTM® (Variable Temperature M
– OoA Cure initially at 65°C -
– Extended outlife for large s

• MTM® (Medium Temperature M
– Autoclave & OoA cure initia
– Structural, aerospace, mari

• HTM® (High Temperature Mould
– Autoclave cure at or above
– Used in aerospace primary

y Prepreg Manufacture

roup (ACG) has been
ms for over 25 years

ding)
but short prepreg outlife
ure for tooling
Moulding)

120°C
structures
Moulding)
ally at 80°C - 130°C
ine and wind turbine blades

ding)
175°C
structures

The Perceived Benefits o
Vacuum B

• Reduces capital expend
avoiding autocalves

• Reduces overheads

• Allows for increased pro

• Increases manufacturin

• Facilitates the manufact
structures

• Reduces core-crush and
problems in sandwich p

• Can result in lower cost

of OoA Processing : Oven
Bag Curing
diture requirements by

oduction flexibility
ng rates
ture of very large

d core stabilisation
panels
t tooling options

The Challenges o

• Achieve internal voidag
autoclave cured materia

• Maintain high fibre volu
• Maintain structural perf
• Achieve flexible cure an

- Prepreg: ud, fabric, bia

• 65°C – 180°C cure optio
• Reduce lay-up times for
• Maintain acceptable pro

achieving OoA objective

of OoA Processing

ge levels as low as
als
ume fraction
formance
nd offer format options

axials, ATL, AFP, combinations

ons

r large structures

oduct outlife whilst
es

Notable Application

• Primary/secondary and
structures

• Airbus secondary wing
• Automotive body panels
• Aesthetic fabric mouldin
• Marine & racing yacht h
• Marine hull tooling
• Infrastructure programm
• Wind turbine blade tooli

ns for OoA Prepregs
prototype aerospace

panel sets
s
ngs
hulls, decking, bulkheads

mes, bridges and repairs
ing and blade parts

ACG’s LTM® Epoxy P

• ACG pioneered the use

• Many LTM® systems we
processing

• LTM® prepregs process
successfully in several
programmes :

– UAV’s
– Prototypes
– Mould tooling

Prepreg Resin Series

of LTM® prepregs
ere developed for OoA

sed OoA have been used
significant aircraft

NASA / McDonnell Dougla

McDonnell Douglas
Bird of Prey

as X36

LTM10
Processed
OoA

Delta Launc

cher Fairings

LTM45
Processed
OoA

DARPA / Lockheed Martin
LTM45EL Pro

n Darkstar UAV Forebody
ocessed OoA

NASA/Orbit
X34 Single Stage to

Boeing X45-A

tal Sciences
o Orbit Demonstrator

LTM45EL
Processed
OoA



LTM45EL
Processed
OoA

Spaceship 1, White Kn

night 1 and Global Flier

LTM45EL
Processed
OoA

OoA Proce

• Fully impregnated UD’s
• Selective impregnation
• Resin and reinforcemen

structured to each appli

• Product consistency
• Zero resin bleed for a
• Controlled resin flow
• Selected resin bleed

air removal.
• Multi-layer reinforcem
• Controlled cure cycle

essing

s
for fabrics.
nt combinations can be
ication.

y is critical.
aerospace.
w.
with large structures for

ment formats.
e.

OoA Proce

• Fully impregnated UD’s
impregnation for fabrics

• Product consistency

• Controlled resin flow

• 100% impregnation is
but fabrics are often

essing

s and selective
s.

y is critical.

w, controlled cure cycle.

s required for UD tapes
differentially coated

Effects of Prepreg Forma

Partially M

impregnated r
Woven
Air released
prepreg through

reinforcement
architecture

Air entrapment between
plies

Fully De
impregnated UD pl
tr
prepreg

at on Laminate Porosity

Matrix infuses
into

reinforcement

Cured
composite

Void-free
laminate

e-bulking the
lies removes
rapped air

OOA Proce
• Fully impregnated UD’s a

fabrics.

• Product consistency i

• Controlled resin flow,

• 100% impregnation is
but fabrics are differen

• Suitable tack and prep

• Application method cr
entrapment

• Tooling can be critica
poor laminates

• Part can be critical, po
laminates

essing
and differentially coated

is critical.
controlled cure cycle.
s required for UD tapes
ntially coated
preg flatness.
ritical to eliminate air

al, poor design leads to

oor design leads to poor

ACG’s 2nd Generation MT
Cure Proc

• MTM46 : For light aircra

- 85°C initial cure capab
- 175°C Tg (dry) after po

• MTM45-1 : Highly tough
secondary structures an

- 90°C initial cure capab
- 185°C Tg (dry) after po

• MTM44-1 : Highly tough
structures

- 130°C initial cure.
- 180°C Tg (dry) / 145°C
- Qualified by Airbus for

wing trailing edge pan

TM® Systems for OOA
cessing

aft (GA), UAV’s etc.

bility
ost-cure.

hened system for primary /
nd prototypes

bility
ost-cure.

hened system for primary

Tg (wet) after post-cure
r use on narrow body aircraft
nels

The worlds largest OOA c
Virgin Galactic / Scaled Co

White Knight 2. Made w

cured aerospace structure.
omposites Spaceship 2 and
with MTM45-1 Prepregs

Void Content of MTM45-1
Typical void conten

Micro-section through
HS Carbon fabric reinf
1220 x 915mm discrim

Laminate Cured OOA

nt < 0.5%

Ply drop
14-12 plies

h a 14-ply 6K-5HS
forced laminate.
minator panel

ACG OoA Processing Tech

Business Jet platform based
upon Dassault Falcon 7X

hnology Demonstrator
d

MTM44-1 OoA Processing

g Technology Demonstrator

MTM44-1 OoA Processin

ng Technology Demonstrator

VTM 240 Automotiv

Specialist Formats – Syntactic and Body P

Syntactic- a lightweight semi structural, fill
supported on a scrim or as a semi-stru
giving rapid thickness build up and low

Body Panel System (BPS 240)
Combination of Surface ply technology an

.lightweight body panel system

Material Panel thickness
/ mm
Carbon BPS240 1.6
Steel 0.7
Aluminium 1.1

ve Body Panel System

Panel System
led resin film, sold by thickness,
uctural ply on a woven fabric
w weight.

nd syntactic ply offered as a

Panel weight Relative
/ kg.m-2 stiffness
1.6
1.88 1.0
1.0
6.28

3.13

ACG – An Out of autocl

lave Experience