1 An Introduction to Aerospace Composite Manufacturing Technology Greg Hasko Applications Engineer Connecticut Center for Advanced Technology [email protected]
1
An Introduction to Aerospace Composite
Manufacturing Technology
Greg Hasko
Applications Engineer
Connecticut Center for Advanced Technology
2
Aerospace Composite Manufacturing Assessment
Introduction
This document is intended to be an introduction to the various
processes used in manufacturing structural composites for
aerospace. We review the raw materials, primary and secondary
manufacturing methods, inspection, emerging methods, and
software tools that enhance the flow of information between
design, analysis and manufacturing. Links are provided to the
sources in each of the topics covered. This document will be
updated on at least an annual basis.
3
page
Part Characteristics – Airframe vs Engine 4
Raw Materials – Fibers, Matrices, Inserts 6
Manufacturing Methods – Shaping and Curing 11
Material Formats 19
Processes & Equipment 25
Emerging Methods 63
Software Tools – Design, Analysis, Manufacturing 71
National Resource Centers 83
Contents
4
Typical Airframe Part Characteristics
• Large dimensions; several feet to 10‟s of feet.
• Low to medium contour.
• Mostly moderate temperature environment.
• Need damage tolerance.
• Some need anti-ice.
• Mostly one part / per part-number / per vehicle.
5
Typical Engine Part Characteristics
• Smaller dimensions; several inches up to
several feet.
• More severe contours.
• Temperatures can go beyond polymer matrix
capability.
• Need damage tolerance, erosion resistance.
• Some need anti-ice.
• Can have multiple parts / per part-number /
per engine.
6
Composite Structures are Created by
Combining the following Materials
• Fibers
• Matrix
• Cores and Inserts
• Adhesives
7
Density
[Lb/in3]
max use
temp [F]
modulus
[MLb/in2]
strength
[KLb/in2]
CTE
[x10-6 in/in/F]
Fiberglass [two types] .091 700 10-13 500-650 3
Aramid [multiple brands] .052 500 17 400 -3.5
Graphite [many types] .063 1000 33/43/64+ 300-800+ -.05
Silicon Carbide .090 2400 28 400 2
Fiber Materials
• Aerospace parts are made from a few types of fibers.
• They vary widely in density, mechanical properties and cost.
• If not planned carefully, fiber deposition can add high labor costs.
• The thermal expansion needs to be accounted for in tool design.
8
Density
[Lb/in3]
max use
temp [F]
modulus
[MLb/in2]
strength
[KLb/in2]
CTE
[x10-6 in/in/F]
Epoxy .046 200 0.5 10 40
Bismaleimide [BMI] .046 300 0.7 15 40
Polyimide .052 500+ 0.5 10 25
Polyethersulfone
[PES]
.049 350 .4 12 27
Polyetherether-ketone
[PEEK]
.048 250 0.5 15 25
Carbon .063 3000+ 1-2 1 1-2
Ceramic .090 2000+ 10 10 2
Metal .10-.16 1000+ 10-17 20-100 5-12
Matrix Materials
• Aerospace parts are made with several types of matrix materials.
• They vary widely in temperature resistance, processing
characteristics and cost.
9
Density
[Lb/ft3]
max use temp
[F]
Fiberglass/phenolic honeycomb 3-8 500
Aramid/phenolic honeycomb 2-9 350
Foam, closed cell, PMA 2-19 300
Syntactics
[glass spheres in resin matrix]
40 200-450
Solid Laminated or Metallic Core Inserts 95-173 200-600
Inserts
Metallic fasteners with special features for strong
joints in composites, typically bonded in place.
Functional Materials Various materials are being embedded to enable
structural health monitoring and actuation.
Cores & Inserts
• Aerospace parts are frequently made in a sandwich construction of
composite skins with low density cores.
• Local inserts are used for strength at joints.
10
Form Characteristics
Paste Usually a 2-part system that is mixed just prior to application.
Some cure at room temperature, some at elevated temperature.
Film Thin films supplied on rolls, and must be refrigerated. They can be
cut and applied in selected patterns. They require heat to cure.
Foaming These are pastes that foam upon cure, to fill hollows in a part or to
splice edges of honeycomb cores.
Powder Tackifier Usually a version of the matrix resin that is applied to dry fabric
used for RTM parts. The powder is used to provide tack to hold
plies together during preforming steps. It should not detract from
the cured mechanical properties.
Nano Additives A wide variety of materials and forms take advantage of the unique
properties at the nanometer level. Order-of-magnitude increases
are possible in mechanical and electrical properties of matrix
resins, adhesives and coatings.
Adhesives
There is a wide variety of adhesives used in aerospace
structures, available in several compositions and forms.
11
Composite Manufacturing
Methods
12
Manufacturing Methods
There are two main approaches for manufacturing of composites, based on
whether the resin is introduced before or after shaping the fibers.
• Choices made in the design of a part influence which branch is
followed, and the types of processes and equipment that are used.
• Cost-effective parts need to be designed with a knowledge of the
processes involved.
• Repeatable quality and cost are achieved by properly specifying all
parameters.
FIBER
RESIN
CURE
RESIN SHAPING
SHAPING
13
Manufacturing Methods
Another way to classify manufacturing processes is by the shaping
and the curing methods.
Curing - Heat & Presure
• Self-Contained Mold
• Press
• Autoclave/Vacuum Bag
• Oven/Vacuum Bag
• Electron Beam/Vacuum Bag
• Pultrusion
Shaping
Fabric, Manual
• Prepreg or, w/ Tackifier
• Stitching
Machine
• Filament Wind
• Braid
• 3D Weave
• Pultrude
• Stitching + fixtures
• Automated Fiber Placement
14
Resin Applied Prior To Shaping [Prepreg Material]
DRY FIBER TOW
RESIN
2D WEAVE
AUTOMATED
FIBER
PLACEMENT
AUTOCLAVE
MOLD
COMPRESSION
MOLD
RESIN
AUTOCLAVE
MOLD
CUT
FILAMENT WIND
LAYUP
PULTRUDE RESIN
ROLL WRAP
The typical sequence for these types of processes:
15
Resin Applied After Shaping [Dry Material]
DRY FIBER
2D WEAVE/BRAID*
3D WEAVE/BRAID*
RESIN
TRANSFER
MOLD*
OVEN,
PRESS CUT
RESIN
*There are many variations of these processes
PULTRUDE
RESIN
FILAMENT WIND/
BRAID OVEN
RESIN
PREFORM
The typical sequence for these types of processes:
16
Design / Manufacturing Information Flow
Information flow is as important as material flow.
Bill of Materials
Sequence of Operations
Ply s/n
Ply orientation
Drawing
Cutting File
3D CAD Model
Ply shapes & s/n‟s
Machine-specific
software for cutting plies
Company-wide
software for
purchasing and
scheduling
Documentation for
technicians
Structural FEA Model
Process FEA Models
[emerging]
Process Specifications
17
Finished Part Manufacturing Methods
Method Guidelines Airframe Engine
Manual Layup / Resin
Transfer Mold
•All surfaces are tooled
•Good for multi-hollow parts
X X
Manual Lauyp / Compression
Mold
•All surfaces are tooled
•Practical size limited by press capacity
X
Manual Layup/Autoclave Mold •Usually one surface is tooled, but can
add caul sheet on opposite side
•High capital and operating costs
X X
Automated Fiber Placement/
Autoclave Mold
•High deposition rates
•Allows continuous fibers over large areas
X
Filament Winding, Braiding •Variable cross section
•Minimal labor
X
Roll Wrapping •High Rate
•Circular sections, tapered
X
Pultrusion •High rate, constant cross section
•Minimal labor
X
Machining •Need special bits, settings, coolant
•Can use ultrasonic, laser and waterjet
X X
18
1. Tooling – to deliver an accurate shape after cure.
2. Accurate fiber placement – alignment within 2° of nominal, uniform
spacing, no wrinkles.
3. Complete resin introduction – no dry spots, typically 40 – 50% by volume.
4. Air removal – minimal void content, below 2%.
5. Compaction – for good strength-to-weight ratio, need from 14 to 150 psi.
6. Cure – needs to be above the maximum service temperature.
7. Finishing operations: machining, bonding, coating.
Common Needs for All Manufacturing Approaches
19
Material Formats
20
Typical Characteristics of Prepreg Materials
Resins are applied to single tows that are up to ¼” wide, or to 2D fabrics,
that are stored on spools. This process, called prepregging, adds cost but
eliminates the need for the part fabricator to worry about resin mixing and
resin content.
The physics of resin flow into fibers limit the ply thickness that can be
made to the range of .005 to .050”. The primary type of resin used in
aerospace is thermosetting, has a limited working time at room
temperature, and must be stored under refrigeration. Thermoset prepregs
are tacky, which aids laying up plies into contoured molds. Thermoplastic
prepregs do not need refrigeration, and are not tacky.
21
Typical Characteristics of Dry Fiber Materials
Dry processing uses the lowest cost form of the raw materials. Resin is
introduced by the Resin Transfer Molding [RTM] process, or by in-line
wetout. The thickness that can be molded is only limited by the resin
characteristics; the flow time before it gels and the threat of exotherm in
thick areas. Some resins give off gaseous byproducts that need to be
removed before cure. Dry fibers are not tacky, and require binder
materials or stitching to stabilize complex shapes. Some binders are
thermosetting and dissolve into the matrix resin.
22
Typical Characteristics of Conventional Fabrics
• Many types; plain, satin, crowfoot, etc.
• Widths can be up to 5‟.
• Large databases of material properties exist.
• The size and type of fiber in each direction can
be varied to create hybrids. An extreme case is
“uniweave”, with heavy graphite in one direction
and fine fiberglass in the other, to approximate
prepreg tape.
23
Typical Characteristics of Non-Crimp Fabrics
• One ply can have multiple layers at different angles, held together by
lightweight knitted fiber; can reduce labor content.
• Cured laminates have higher properties than conventional weaves.
• Widths can be up to 12‟.
24
To improve impact, strength and thermal properties in the
thickness direction, a variety of methods are available:
• 3D Weaving & Braiding – Jacquard looms, etc
• Stitching – industrial strength
• Z Pins – small embedded composite pins
3D weaving and braiding also reduce ply layup labor;
however the linear production rate is slower than 2D fabrics.
Methods to Increase Through-Thickness Properties
25
Manufacturing Processes
and Equipment
26
This is the traditional method, needing trained
technicians. It can be done with prepreg and dry
material. To form the material around tight
contours without wrinkling, relief slits or „darts‟ are
cut. Fibers within a ply shear and skew as they
are placed onto contoured molds. The pattern of
darts and the sequence of laying down the
perimeter of large plies needs to be repeated from
part to part.
This method is susceptible to FOD being cured
within the laminate; gloves, tape, knife blades, etc.
Hand Layup
27
Ply Placement Templates and Draping
For repeatability when using hand layup, guides
are needed to align ply directions and edges.
These guides can be scribe lines on molds, mylar
sheets, or fabricated metal or composite templates
that pin into location at the edge of the mold.
Plies at the edge of a part may have extra tabs
designed into the flat patterns to allow verification
by an inspector. These tabs are trimmed off after
cure.
Note that the weave pattern distorts when placed
onto a contoured mold. The hoop strength of the
red zone is much different than the blue zone. The
designer must specify the draping method, and this
information must be transmitted to the shop floor.
See the Software section for packages that can
simulate draping. +/-30° 0/90°
28 Video-Guided Ply Placement
Laser-Guided Ply Placement
CAD-Driven Ply Placement Guides
Projectors that operate from CAD data
display ply patterns and fiber angles onto
the mold during hand layup. Line width
adjustment is needed in highly sloped
areas. Tolerance bands can be indicated
in the projected pattern.
29
These machines are used for dry or
prepreg material. Ply shapes are
determined manually and scanned into
a digital data file, or determined from
software that models draping and
flattening for contoured shapes.
Software is also used to pack the ply
patterns efficiently to minimize waste
when cutting.
CNC Ply Cutter
30
Modified „shoelace‟ machines are used, usually with dry fibers.
Braided sleeving can be packaged on a spool for hand layup,
or contoured mandrels can be fed through the machine to
braid onto the net shape. Braided preforms typically go into an
RTM process, although prepreg and in-line wetout have been
demonstrated.
Large commercial braiders have an approximate 7-foot ID,
which can be fully covered with near-hoopwise fibers.
However, another limit is the diameter that can be fully
covered at a given angle with the fiber bandwidth of about
.25”. The maximum diameter that can be fully covered at a 45
degree angle is 8”. Specialty braiders exist that are almost
four times this size.
Since all the spools on the machine must pass over and under
each other, they are smaller than those on weaving looms.
Therefore, reloading time is a factor in determining the
maximum attainable length and cost. Typical parts include
propeller spars, missile bodies, bushings, accessory beams.
Braiding Processes
31
Braiding machines can be set up to deliver one or two sets of fiber; a biaxial set and an
axial [0 degree] set. The combination of biaxial and axial is called triaxial. The angle
of the biaxial fibers can range from nearly 0 degrees to nearly 90 degrees. Different
types and weights of fiber can be used to create hybrids. The choices of these
parameters depend on the structural and cost requirements.
Straight and curved parts can be made by using appropriate mandrel handling devices.
The cross-section can not have concave areas, or the fibers will bridge. Severe cross
section changes can be accommodated, such as the transition from the cylinder to the
flange of a bushing. The mandrel can be reciprocated back and forth to build up
layers. Other fabrics and core materials can be inserted between layers. Removable
pins on the mandrel enable net-shaped holes without drilling.
Braiding Parameters
0 0
Biaxial Triaxial
32
3D fiber architectures and shaped cross-
sections [I, T, hollow, etc] are made on
braiders that control the motion of every
fiber spool. Jacquard weaving looms
control the interweaving of each yarn to
achieve similar results.
3D Braiding and Weaving
3Tex I-Beam
3D Braider
Jacquard Loom
Individual yarn
controller
33
Dry fibers are pulled through a resin applicator
and a curing die. Shaping and curing occur nearly
simultaneously. Typical parts are floor beams and
strengthening inserts in wing spars. Entire wing
sections have been demonstrated.
Parts are limited to straight, constant cross-
sectional shapes. Parts to several feet in width
can be pultruded, given enough pulling capacity.
Length is limited only by the creel capacity and
take-up provisions. Fabrics, cores and inserts can
be incorporated.
A variation called Pullforming is used in the
automotive industry to make leaf springs. Wet
fibers are drawn onto a heated rotating mandrel
having a shaped cavity.
Pultrusion Process
34
Resin Transfer Molding Processes
In this process dry preforms are enclosed in a mold, then a thermosetting
resin is introduced. This reduces capital and operating expenses
compared to autoclave curing. Very complex parts can be made, such as
vane/ring packs. Resin selection is limited to those that have low
viscosity [<1000 cP], for long enough time [typically 1 hour] to complete
the injection. There are numerous variations, basically divided into
matched mold and bag mold methods. There are some similarities to
plastic injection molding, but the resin is much lower in viscosity and the
cure cycle is much longer than a quick cooling cycle. Part quality is
improved with dry nitrogen purging followed by vacuum.
RTM Transmission Fitting
• Thick-wall graphite composite.
• ~20-piece mold was used.
• Final edges were machined.
35
Preforming for RTM Processes
A binder is applied to the fabric before plies are cut out. Plies are
shaped and stabilized on preforming molds, usually with vacuum and
some heat, prior to assembly into the RTM mold. This increases
preform repeatability and reduces the RTM mold cycle time.
Stitching is also used to make shaped preforms, and in addition provides
translaminar strength. Fixtures hold the fabric in alignment during the
stitching process.
36
RTM in a Matched Mold
RTM Mold
Injector or pressure pot
Vacuum Pump
RTM in a matched mold provides an excellent finish on all surfaces. It
enables using 3D textile preforms that can not be made by prepreg
methods. Parts are typically up to a few feet in size.
The preform has a great influence on the flow pattern. The closed mold
is a pressure vessel [typically 100 to 200 psi], and needs great stiffness
to yield parts with uniform wall thickness.
37
Typical Features of RTM Molds
• Inlet and outlet ports – locations optimized to completely fill the preform.
• High stiffness to resist preform compaction and resin injection pressures.
• Clamps - either around the perimeter, or use an external frame or press.
• Heating – can be integrally heated with electric rods, steam, or hot oil, or a press or oven can be used.
• Sensors – thermocouples and other types to monitor pressure and degree of cure.
• Vacuum-tight; O-rings enclose the part cavity.
• The mold can have multiple cavities.
• Molds may have over 100 internal pieces, manually assembled.
• Trapped mandrels are removed using melt-out or wash-out materials.
38
This is done on a one-sided mold, with a vacuum
bag on other side. Resin is drawn into the
preform with vacuum. A high-flow media can be
placed over the preform so that resin quickly
spans large parts. The bagged side has a
rougher surface than the mold side after cure.
Mechanical properties are typically lower than
with an autoclave pressure cure or with matched
mold RTM. Parts can be up to 10‟s of feet in size.
Vacuum Assisted Resin Infusion [VARI] Process
39
Resin Film Infusion [RFI] Process
This is a variation of VARI, using a one-sided mold and a vacuum bag on
other side. A solid resin film is placed on the mold, then covered with the
preform and a vacuum bag. As this assembly is heated, the resin melts and
flows into the preform under vacuum pressure. This process can also be
done in an autoclave for additional compaction and driving pressure.
As with prepreg and VARI, the bagged side has a rougher surface than the
mold side after cure. Parts can be to 10‟s of feet in size.
Can have very thick preforms
Solid resin film
Resin melts
and flows
Mold
Vacuum bag
40
For VARI processing an open container will
suffice, since resin is drawn in with a
vacuum pump. For injection into a matched
mold, a pressurized paint pot can be used.
Positive displacement pumps enable
computerized process control and recording.
Meter-mix machines can be used with dual
component resins.
Most resins need to be heated to reduce
viscosity, so heated chambers and delivery
hoses are available.
RTM Injection Equipment
41
Prepreg materials can be cured in a matched mold
as in RTM, giving good surface finish throughout
[as opposed to bag methods such as autoclave or
VARI].
Maximum size is governed by press capacity,
typically up to several feet. Vacuum is typically not
needed. Proper sequencing of pressure during the
heat cycle is critical to making void-free parts with
proper fiber alignment. Typical parts are stator
vanes.
Compression Molding Processes
42
This uses a device similar to a lathe. A revolving mandrel is
covered with fibers kept under tension. It can be done using in-
line wetout, prepreg, or dry fiber followed by an RTM cure.
Curing is normally in an oven. External cauls or shrink wrap
film can be used for compaction. Typical parts are pressure
tanks and rocket bodies.
Since fibers are kept under tension, the cross-section can not
have concave areas or the fibers will bridge. They must either
lay down in geodesic patterns normal to the local contour, or
extra mechanical means such as pins or friction must be used
to prevent slipping. These factors must be observed in the
design phase. The fiber angle can range from 0 [with
appropriate restraints at the ends] to 90 degrees to the rotation
axis. Large spools of fiber can be used, as in weaving.
Shapes are limited to the number of controlled axes of the
machine; slightly tapered straight parts such as truss tubes can
be made on a 2-axis machine, whereas curved parts with
closed ends may require 5 axes. Length and diameter can
range up to 10‟s of feet. Parts have been made over 100‟ long
with over 1” wall thickness.
Filament Winding Processes
43
Automated Fiber Placement [AFP] takes filament winding
a step further. It uses prepreg fibers placed onto a
contoured mold with a multi-axis head. Fibers are
stabilized by the resin tackiness and contact rollers. Labor
content is reduced and speed increases compared to hand
layup. Typical parts are fuselage and nacelle skins.
The size can be 10‟s of feet on a side. Both the mold and
the fiber placement head are in motion. Individual fibers
can be cut and restarted to cover any shape at any angle.
As opposed to filament winding, concave features are
permissible.
Parts are vacuum bagged and cured in an autoclave.
See videos:
http://www.automateddynamics.com/video_library.php
Automated Fiber Placement Processes
44
Special machines have been developed
to deposit prepreg fabric. They can lay
fabric on a mold and trim the edge. They
are used for mildly contoured shapes
such as wing skins.
A variation is to use a “pick and place”
robot to stack pre-cut plies on a mold.
Robotic Ply Layup
Broetje pick and place robot
45
Prepreg is rolled onto a mandrel and
cured in an autoclave, or shrink wrapped
for an oven cure. Mandrels must be
straight and circular, but can be tapered
or stepped. Tables typically are
designed for parts up to 10‟ length and
up to 6” diameter. Typical parts are truss
tubes.
Tube Rolling Table
46
Heated pressure vessels are normally
used to cure prepreg materials. They
can be 10‟s of feet in diameter and
length. One-sided molds are
normally used, and several parts that
have the same resin can be cured
together. Resin Film Infusion into dry
preforms has been demonstrated on
large parts having translaminar
reinforcement.
Autoclaves
47
Used for compression molding
and RTM. Heat is supplied by
electric cal rods or an oil system.
Presses typically have one axis of
motion for slightly contoured
parts, but custom presses have
been built with multiple axes.
Heated Press
48
Ovens can be 10‟s of feet in length,
width and height. They may have a
rotisserie for filament wound parts, to
avoid resin pooling. They are used
for heating bolted RTM molds or
vacuum-bagged VARI molds.
Heating can be electric, gas or oil.
The floors may need to withstand
multi-ton molds.
Ovens
49
Inspection Methods, In-Process and Post-Cure
This is a dynamic, rapidly evolving area that entails a variety of physical
principles. In-process checks are done to verify proper ply sequence, ply
angle, and ply edge location. Post-cure inspections check for non-desirable
items such as wrinkles, voids, delaminations, and embedded foreign objects.
In some methods the structure is passive, with defects creating a disturbance
to an applied signal. In others the structure is mildly disturbed with heat or a
mechanical load, and the surface is scanned for indications that print through.
Acousticam Sonatest Wheelprobe
50
The tool bits, feeds, speeds and coolants
used to machine composites are specific
to the matrix and fiber combination.
Excessive heating causes polymeric
resins to decompose. Improper cutting
tools can pull fibers out of the resin
locally. Lasers and waterjets are used,
especially on ceramic matrix composites
where the part is made out of similar
materials as the cutting tools themselves.
Residual stresses locked into the part
during cure can cause parts to deform or
delaminate during machining.
Machining
Trim & Drill Fixture
51
Custom-designed fixtures are used to hold
parts accurately and maintain bondline
thickness despite thermal expansion
effects. They can be self-heated or used
in an oven. For quality control they are
instrumented with thermocouples.
Bonding Fixture
52
Composite Manufacturing
Related Companies
53
Method Company Web site
Manual Layup /
RTM
V Systems
ITT Integrated Structures [ex Fiber Innovations]
AAR Composites
Albany Engineered Composites
GKN-CT/AL/St Louis
Cobham [ex Sparta]
North Coast
www.vsc-inc.com
www.defense.itt.com
www.aarcorp.com/composites
www.albint.com/aec
www.gknaerospace.com
www.composites.sparta.com
www.northcoastcomposites.com
Manual Lauyp /
Compression
Mold
GKN-CT/AL/St Louis
CTL Aerospace
CHI
Matrix
Cobham [ex Sparta]
www.gknaerospace.com
www.ctlaerospace.com
www.chi-covina.com
www.matrixcorp.com
www.composites.sparta.com
Finished Part Manufacturers
This is a partial list of aerospace manufacturers by process type. For a
more extensive list see sources such as the annual Composites World
Sourcebook [www.compositesworld.com/].
54
method company
Manual Layup/
Autoclave Mold
Spirit Aerosystems
GKN-AL
ITT Integrated Structures
Vermont Composites
V Systems
Hexcel
Kaman
Matrix
Cobham [ex Sparta]
Tighitco
www.spiritaerosystems.com
www.gknaerospace.com
www.defense.itt.com
www.vtcomposites.com
www.vsc-inc.com
www.hexcel.com
www.kamanaero.com
www.matrixcorp.com
www.composites.sparta.com
http://www.tighitco.com/
Filament Winding Lincoln www.lincolncomposites.com
Pultrusion Kazak www.kazakcomposites.com
Automated Tow Placement/
Autoclave Mold
Vought
ATK
Hitco
www.voughtaircraft.com
www.atk.com
www.hitco.com
Finished Part Manufacturers
55
Method Equipment Maker
Compression
Molding Press
Wabash
Pacific Press
Technical Machine Products
www.wabashmpi.com
www.pacific-press.com
www.techmach.com
Autoclave Tarrico
American Autoclave
ASC Process Systems
www.tarrico.com
www.americanautoclave.com
www.aschome.com
Automated Fiber
Placement Machine
MAG Cincinnati
Ingersoll
Automated Dynamics
Electroimpact
Accudyne
www.mag-ias.com
www.ingersoll.com
www.automateddynamics.com
www.electroimpact.com
www.accudyne.com
Finished Part Manufacturing Technology Providers
This is a partial list of equipment manufacturers by equipment type. For a
more extensive list see sources such as the annual Composites World
Sourcebook [www.compositesworld.com/].
56
Method Equipment Maker
Filament Winder Entec
McClean Anderson
www.entec.com
www.mccleananderson.com
Oven Wisconsin
Grieve
www.wisoven.com
www.grievecorp.com
Robotic Ply Layup Composite Systems
Diaphorm
www.compositemfg.com
www.diaphorm.com
Finished Part Manufacturing Technology Providers
57
Equipment Makers
Ply Projection Virtek
LAP Laser
Anaglyph
Laser Projection Technologies
Assembly Guidance Systems
www.virtek.ca
www.lap-laser.com
www.anaglyph.co.uk
www.lptcorp.com
www.assemblyguide.com
Ply Cutters Gerber
American GFM
Eastman
www.gerbertechnology.com
www.agfm.com
www.eastmancuts.com
RTM Injectors Radius
Graco/Liquid Control
www.radiusengineering.com
www.graco.com
Non-contact
Dimensional
Measurement
Stienbichler
Creaform
Twin Coast
www.steinbichler.de
www.creaform3d.com
www.twincoastmetrology.com
Ancillary Manufacturing Methods
This is a partial list of equipment makers by equipment type. For a more
extensive list see sources such as the annual Composites World
Sourcebook [www.compositesworld.com/].
58
Equipment Makers
Laminate
NDI
• Physical Acoustics - Acoustic Emmission
• Imperium - Digital Acoustic Video
• A2 - Exoscan handheld FTIR
• Evisive - Microwave Scanning
• LSP Technologies - Laser Bond Inspection
• Photo Emission Tech - UV Surface Excitation
• Advanced Structural Imaging - Computer-Aided Tap Test
• Boeing - Mobile Automated Ultrasonic Scanner [MAUS]
• Digiray - Motionless Laminography X-Ray
• Steinbichler - Laser Shearography
www.mistrasgroup.com
www.imperiuminc.com
www.a2technologies.net
www.evisive.com
www.lsptechnologies.com
www.photoemission.com
www.asi-nde.com
www.boeing.com
www.digiray.com
www.steinbichler.de
Inspection Methods
59
Equipment Makers
Laminate
NDI
• Laser Technology - Laser Shearography
• Thermal Wave Imaging - Pulsed Thermography
• Wichitech - Electronic Digital Tap Hammer
• Quality Material Inspection - Air-coupled Ultrasound
• Honeywell International - Structural Anomaly Mapping
System [SAM], acoustic/laser
• Lockheed - Laser Ultrasonic Technology
• PaR Systems - Laser Ultrasonic Technology
• iPhoton - Laser Ultrasonic Technology
• Mitsui Engineering - Woodpecker automated tap tester
• Sonatest - Ultrasonic wheel probe array
www.laserndt.com
www.thermalwave.com
www.wichitech.com
www.qmi-inc.com
www.honeywell.com
www.lockheedmartin.com
www.par.com
www.iphoton.com
www.mes.co.jp
www.sonatest.com
Inspection Methods
60
Precursor Manufacturing Technology Providers
Equipment Makers Equipment Users
Uniweave, Dry &
Prepreg
Western Advanced Engineering Hexcel, Cytec, Nelcote, APCM, YLA
Plain & Satin Weave,
Dry & Prepreg
numerous Textile Products Inc, Hexcel
Braid, Dry Wardwell, Steeger, Hacoba, Herzog ITT, A&P, Bally Ribbon, Albany
Techniweave, Fabric Development
Non Crimp Fabrics Liba, Malimo, Mayer Saertex
Filament Wind Entec, McClean Anderson Lincoln
3D Weave 3TEX 3TEX, Bally, Fabric Development,
TEAM, Albany Techniweave
Stitched Fabrics, Dry Puritan Boeing
Z-pins, Prepreg Albany Techniweave
This is a partial list of manufacturers by material type. For a more
extensive list see sources such as the annual Composites World
Sourcebook [www.compositesworld.com/].
61
Activity Issues
Ply Layup & Forming • Need automation; constitutes large portion of part
fabrication labor.
Part Trimming • Labor content and accuracy can be improved by multi-
axis CNC.
Nondestructive Evaluation
• Laminate integrity
• Cure state
• Ply Angle Verification, Post-Cure
• Need a nondestructive method to verify ply angles and
ply boundaries.
• Need NDI instruments that can reach into tight spaces.
• Need to map defects into 3D CAD files.
Physics-Based Process Simulations
• RTM – avoid dry spots, resin
racetracking, local exotherm
• Compression Molding – avoid „horsetails‟
expelled from mold
• Autoclave Flow – ensure thermal
uniformity with an arbitrary loading of
parts
• Need software to be more user-friendly for front-line
engineers.
• Need to quantify material processing parameters
accurately.
Mold Design for In-tolerance Parts • Use physics-based design tool to account for warping
[see Convergent Manufacturing Technologies, Inc].
• Need to quantify material parameters accurately.
Issues With Manufacturing Processes
62
Issues With Manufacturing Processes
Activity Issues
Molecular Sensors For Process Control.
•fiber optic
•dielectric
• Better control than a canned time/temperature profile.
• Need user-friendly systems to install in production
molds.
• Need accurate material characterization.
• Need affordable systems.
Prepreg Perishability • Avoid manual data logging. RFID is being applied to
insure that material is used on time.
Out-of-Autoclave Curing • Reduce energy consumption and capital expense of
pressure vessel.
• Need materials designed for vacuum-only cure cycles.
Resin Cure Time • Resins typically need multi-hour cure cycles. This
requires multiple molds and curing systems for high-
rate production.
RTM with Intractable Resins • High viscosity, short pot life
• Advanced cure cycles – sum up the viscosity dips
• Port configuration – thru-thickness flow
• Combination - sequential porting
63
Emerging Methods for
Composite Manufacturing
64
Roctool Inc
http://www.roctool.com/
Rapid heating by an array of induction heads.
Quickstep Inc
http://www.quickstep.com.au/what-is-
quickstep
Applies heat and pressure by liquid instead of gas
for quicker heat transfer.
2PHASE Inc
http://www.2phasetech.com/
Reconfigurable mold surface for rapid prototyping or
repairs.
Electron Beam Curing
www.ebeamservices.com
www.acsion.com
Quick cure without thermal effects. Need radiation
shielding and resins designed for this process
3D Shape Weaving [Shape3 Inc]
http://www.shape3.com/
Seamless net-shape preforms; no cut fibers.
P4 Process
http://www.compositecenter.org/index.php/r
apid-fiber-preform.html
Discontinuous fibers applied onto molds in controlled
patterns to avoid manual ply layup.
Out-Of-Autoclave processes
http://www.advanced-
composites.co.uk/PSG_Electronic_Files/A
erospace_PSG_Files/outofautoclave.html
Prepreg materials are being developed to enable
curing and acceptable properties without the capital
investment for an autoclave.
Emerging Manufacturing Technology
65
Induction heating is used to selectively
heat the mold for rapid cycling and low
energy use compared to conventional
heating. This is used for RTM with dry
preforms and compression molding with
prepregs.
Size: custom-designed.
Roctool
66
This is a self-contained molding system
with a rapid heatup/cooldown system.
Molds float in a liquid media, so molds
require less stiffness than in other cure
processes. It can be used for bagging
processes such as autoclave/prepreg,
VARI and RFI.
Size: up to 20 sq yd area.
Quickstep Molding System
Mold
Controls
Tanks for liquid
pressure and heating
media
67
This is a reconfigurable mold that uses a
liquid/particle media contained by a
membrane that solidifies against a master
shape. The media can be re-liquified and
re-solidified, and can potentially be
sculpted to net shape with a CNC
machine. Molds up to several feet on a
side by 2 feet deep have been delivered.
Reconfigurable Mold, 2Phase, Inc
68
Net-Shape Weaving
Net shape contoured weaving has been
demonstrated by Shape3, but has not
been in high rate production. To cure the
final composite a process such as VARI
would be used.
http://shape3.com/
69
Electron Beam Curing
Composites are cured without heat in
a radiation-shielded accelerator. The
beam is scanned over the entire part.
Only resins designed for e-beam cure
can be used. Molds can be made
from wood or rigid foam.
•see www.acsion.com
70
Discontinuous Fiber Preforming, P4 Process
Chopped, tackified fiber is sprayed onto a
porous vacuum form with a CNC robot. The
preform then goes into an RTM mold for resin
injection and cure. This reduces labor content
and increases deposition speed compared to
hand layup. Somewhat lower mechanical
properties result than with continuous fibers.
Vacuum mold
Chopper/sprayer
71
Composite Manufacturing
Process Design and Modeling
Software Solutions
72
Composite Processing: Steps & Simulations
Simulation tools are becoming available to assist manufacturing engineers. Orient Fibers
draping
tow placement
nesting
geometry & motion
Resin Flow
reaction kinetics
heat flow
viscosity kinetics
fiber compaction
geometry, coupled diff e's,
molecular mobility sensing
Heat Resin
reaction kinetics
thermal & chemical eq's
Resin Cure
reaction kinetics
Heat flow
CTE build
Tg build
modulus build
resin bulk shrinkage
geometry, coupled diff e's
Cooldown
residual stress buildup
geometry, coupled diff e's
Demold
remove constraints
relieve stress
residual deformation
geometry, coupled diff e's
Mix Resin
reaction kinetics
chemical eq's
COTS Software
Raw Materials
Into Service
Design
intent
achieved
Machining
remove material
relieve stress
residual deformation
geometry, coupled diff e's
73
Features Web Site
NX
[formerly UG]
Has fabric draping features and
micromechanics calculator.
www.plm.automation.siemens.com
CATIA Dassault product, has fabric draping,
integration between design/analysis/
manufacturing.
www.3ds.com
Pro-E Sister product is Pro Mechanica FEA. www.ptc.com
CAD Tools
Not all CAD tools can easily handle composite ply information.
Here are some that do:
74
Features Web Site
ANSYS General purpose, has composite
elements
www.ansys.com
NASTRAN General purpose, has composite
elements
www.mscsoftware.com
www.plm.automation.siemens.com
ABAQUS General purpose, has composite
elements. Affiliated with
Dassault/CATIA.
www.simulia.com/products/abaqus_fea
MARC Good for nonlinear materials www.mscsoftware.com/products/marc.cfm
?Q=131&Z=396&Y=400
Pro-E/
Mechanica
Sister product of Pro-E, has
composite laminate features
www.ptc.com/products/proengineer/advan
ced-mechanica
LS-DYNA Impact & crash simulation www.lstc.com/lsdyna.htm
Lusas General purpose, has composite
elements
www.lusas.com/products/composite
ARPPAS Specialized package for repairs http://www.fea-llc.com/
StressCheck Has composite laminate features www.esrd.com
Structural Finite Element Analysis Software
75
CAD & FEA Translators
Features Web Site
Altair - Hypermesh CAD defeaturing and
repair, mesh generation
http://www.altairhyperworks.co
m/Product,7,HyperMesh.aspx
Elysium - CADdoctor CAD defeaturing and
repair
http://www.elysiuminc.com/
Anark convert and transform
3D CAD and related
product information
http://www.anark.com/
Due to the large number of software packages and vendors on the market,
there is an industry issue of file compatibility and interoperability. Supply chain
companies frequently encounter errors when converting surface and mesh data
from customers, needing time-consuming repairs before proceeding with the
value-added tasks at hand.
Tools exist to ease file translations between CAD and FEA formats. Some are
listed here:
76
Examples of Mold Flow Simulation
Vacuum Infusion
• How much time will it take to fill?
• Will gravity affect the fill process?
Matched Mold Injection
• Where should the runners be placed?
• How much pressure will it take to fill?
77
Type Features Web Site
RTM Flow
PAM-RTM Resin flow, fabric draping, reacting
resin, transient heating.
www.esi-group.com/products/composites-
plastics/pam-rtm
LIMS Resin flow www.ccm.udel.edu/Pubs/techbriefs/LIMS.pdf
RTM-Worx Resin flow www.polyworx.com
Composite Cure Springback
COMPRO Plug-in to ABAQUS and MARC,
calculates residual stresses and
springback due to resin cure.
Point solutions for resin cure can
be obtained using their Raven
package.
www.convergent.ca/products/compro%203d/
overview.html
Finite Element Based Process Simulation Tools
Physics-based models can be applied to arbitrary shapes. Proper simulation
requires that the processing properties of the materials be quantified in the code.
78
Example of Springback Simulation
• Composite resins shrink much more
than the fibers when curing.
• Thermal expansion of some mold
materials is much different than the
composite.
• When a simple 0/90 ply layup is
molded on a flat plate, the cured
part springs into a curved shape.
• This behavior can require re-
machining the mold after the first
part is made and measured.
• Simulations can be done to account
for this; to design the mold surface
properly in the first place.
90° ply
0° ply
Flat mold
79
Fabric Draping and Flat Patterns
Flat Pattern
A
B
Draped on Hemisphere
A B
A unique feature of composite fiber plies is that they shear and skew
as they are placed onto a contoured mold. Since fiber angles
drastically affect mechanical and processing properties, both the
designer and the manufacturer need to specify and control this
behavior. The flat cutting patterns depend on the draping behavior.
Software packages exist to plan the plies correctly.
Fibers at B are
highly skewed
on the mold
80
Type Features Web Site
Fabric Draping and Flat Patterns
Fibersim Plug-in to NX, CATIA, Pro-E. www.vistagy.com
Laminate Tools Stand-alone CAD/FEA interface for
composite plies.
www.anaglyph.co.uk
Simulayt Plug-in to CATIA/ABAQUS. www.simulayt.com
PAM-RTM/Quickform Part of PAM-RTM. www.esi-
group.com/products/composites-
plastics/pam-rtm
Interactive Drape Interactive, inexpensive fabric draping
simulator.
www.interprot.com/
Patran/Laminate Modeler Has fabric draping function. www.mscsoftware.com
‘Soup to Nuts’
ITOOL European effort to model fabric unit
cells, fabric draping, RTM flow and
structural response.
www.itool.eu
Process Simulation Software Tools
Geometry-based tools can be applied to neutral CAD surfaces and FE meshes.
81
Type Features Web Site
Filament Winding
Entec Models tensioned fibers on a
rotating mandrel.
www.entec.com/
CADWIND Models tensioned fibers on a
rotating mandrel.
www.material.be/filament-winding-
software
Auto Tape Laying, Auto Fiber Placement
Vericut Can model various machines. www.cgtech.com
Fiber Placement Expert
System
Can model various machines. www.compositepro.com/Fipes.html
ACES By MAG Cincinnati for their
machines.
http://cinmach.mag-
ias.com/products/automated-
composites-processing/aces
Process Simulation Software Tools
82
Features Web Site
Composite Pro Calculator to determine stiffness
properties of laminates, and structural
response of simple shapes.
www.compositepro.com
Helius Calculator to determine stiffness
properties of laminates. Will be adding
textile composites.
www.fireholetech.com
Texcad,
mmTexlam
Calculator to determine stiffness
properties of textile composites. K. Shivakumar [[email protected]]
ITOOL Determine stiffness properties of textile
composites
www.itool.eu
Hypersizer Calculator to determine stiffness
properties of laminates, and structural
response of simple shapes.
www.hypersizer.com
Sysply Calculator to determine stiffness
properties of laminates
www.esi-
group.com/products/composites-
plastics/sysply
Laminate Property Calculation
83
Connecticut Center for Advanced Technology www.ccat.us
University of Delaware Center for Composite Materials www.ccm.udel.edu
University of Dayton Research Institute www.udri.udayton.edu
Air Force Research Lab, Materials Directorate www.wpafb.af.mil/afrl/rx
NASA, Langley & Glenn Research Centers www.nasa.gov/centers/langley/home/index
www.nasa.gov/centers/glenn/home/index
National Composite Center www.compositecenter.org
Composites Manufacturing Technology Center http://cmtc.scra.org/about_cmtc.shtml
National Institute for Aviation Research www.niar.wichita.edu/researchlabs/comp_ov
erview.asp
National Center for Manufacturing Sciences www.ncms.org
Composites Manufacturing Technology Center http://cmtc.scra.org/tcc_overview.shtml
Composite Materials Resource Centers
84
Composites World
Magazine
Covers a wide range of
design/analysis/manufacturing topics.
Publishes annual supplier listing.
www.compositesworld.
com/
Journal of Composite
Materials
Peer-reviewed academic journal. http://jcm.sagepub.com
American Society for
Metals
Publishes detailed handbooks on various
materials. For composites see ASM Handbook
Volume 21.
asmcommunity.asminte
rnational.org/portal/site/
www/
Society for the
Advancement of Material
and Process Engineering
Conducts annual conferences on composite
properties, design and fabrication.
www.sampe.org
Society of Manufacturing
Engineers/Composites
Group
Conducts annual conferences on tooling and
manufacturing
www.sme.org
Consortium for
Improving/Integrating
Advanced Composites
Processes (CIACP)
Brings together design and manufacturing
technologies.
Conducts regional conferences.
www.agfm.com/Initiativ
es/CIACP.htm
American Society for
Composites
Promotes the exploitation of the unique
properties of composite materials in emerging
applications.
www.asc-
composites.org
Composite Materials Associations & Publications