Composites 101 Workshop

R.A. (Dick) Lofland – Richard Lofland and Associates Carroll Grant – Aerospace Composites Consulting Workshop will be conducted as a “101” overview of the composites industry …..Presentation material has been developed for people who know very little about the composites industry

Workshop intent is to provide attendees with a basic understanding of “composites”

Workshop will focus on “aerospace” composites as this is experience base of the instructors • Composites Industry Overview (Carroll Grant) ……history and industry segments ……materials and design basics

• Aerospace Composites Processes ……basic processes (Dick Lofland) ……automated Processes (Carroll Grant)

• Inspection of Composite Parts (Dick Lofland) ..….two primary processes

• Questions & Comments

• A special thanks to Dave Dickson of Boeing 1 2 What are composites?

• A “composite” is a material form made of at least two materials – Visually distinct: you can see the and resin areas • The Advanced Composites that we use for Aerospace typically have a “matrix” (e.g. an or BMI resin) and a “reinforcement” (can be carbon fiber, fiberglass, Kevlar, etc.) • Two main classes of advanced composites: thermoset and thermoplastic. – Thermoset – cross-linking of the resin molecules is not reversible. – Thermoplastic – possible to re-heat and melt the resin • Other types: matrix, matrix • Materials are very unique in their properties and applications • Many processes involved in creating high-quality parts – Attention to detail very important - must get each step right!

3 What’s an “Advanced Composite”?

• Advanced Composites are typically thought of as those with fiber volumes (or fiber fractions) greater than 50% – Qty of fiber / total composite laminate including fiber & resin • Typical aerospace Advanced Composites have fiber volumes of around 55% • Materials used and manufacturing processes deliver these types of parts.

Usually Not 787- Advanced Composite Advanced Composite

4 Boeing illustration Dickson photo Advantages of Composites

• High strength/weight • Low CTE • Excellent in fatigue properties 747 – 1% composite: 1M fasteners • Won’t corrode • Can tailor laminate to loads • Can enable very significant

part count reductions 787 – 50% composite: < 10K fasteners

5 Boeing Photos Sampling of Composite Products

Boeing 7871 BMW i32 Windmill Blades3

Various Sporting Goods5 Blackbird Guitar4 BMW/Oracle America’s Cup Yacht6 6 The Main Constituents

: Carbon, , Kevlar® (Aramid), , Quartz & other natural fibers (hemp, flax, basalt) • Matrix (resins): Thermosets, Thermoplastics, and (both less common) • Cores & inserts (honeycomb, foam, balsa, grommets, etc.) at times.

Main focus of this presentation will be Carbon Fiber/Epoxy laminates 7 Resins

• The matrix (resin) transfers load from fiber to fiber • Resins are typically high CTE materials; the fibers are most typically low CTE • Thermosets: Epoxy, Bismaleimide (BMI) & phenolic most typically for aerospace. Others: polyester, vinyl ester, cyanate epoxy, etc. – Resin constituents cross-link (cure) in a chemical reaction: shape is permanent . • Thermoplastics: PEEK, PEI, PPS, PEKK most typically for aerospace. Others: PP, PS, PET, PA, TP PI – Resin melts and solidifies on cool-down. Can be re-melted and re-formed to different shape.

8 Fibers and Yarns

• Carbon Fibers are actually quite small. Fibers are bundled together to make yarns. • The Yarns, or “Tow” come in many sizes: Fibers are 5 microns in diameter7 – Small Tow: 3K, 12K, 24K – Large Tow: Larger than 24K • Example – 1K fiber has 1,000 fibers per yarn

9 Producers of Carbon Fiber

Hyosung

SGL

Zoltek

Mitsubishi Rayon Toho Tenax

Toray

HPC March 2013: http://www.compositesworld.com/articles/market-outlook-surplus-in-carbon-fibers-future 10 (Chris Red, Composites Forecasts & ConsultingLLC – Present. from CW Carbon Fiber 2012) Used by permission. Production of CF by Tow Size

HPC March 2013: http://www.compositesworld.com/articles/market-outlook-surplus-in-carbon-fibers-future 11 (Chris Red, Composites Forecasts & ConsultingLLC – Present. from CW Carbon Fiber 2012) Used by permission. How are carbon fiber prepreg materials made? • PAN (Polyacrylonitrile), pitch or rayon precursors • Superheated to 4900°F (pyrolysis) • Spun into fiber Harper CF Oxidation Line8 • Ultrahigh heating, oxidation, carbonization & graphitization • PAN-based: typically higher strength • Pitch based: higher modulus • Rayon-based – industrial grades • Aerospace companies typically use PAN-based fibers

12 Carbon Fiber Properties

• Fibers that are made into prepregs come from several providers – Hexcel (HexTow) , Toray (Torayca), Mitsubishi Rayon (Grafil), Toho (Tenax), Cytec (Thornel) – there are others. • Aerospace fibers tend to be categorized by their modulus

Tensile Modulus Tensile Strength

1 High-VolumeGrade <25MSI 250–500KSI StandardModulus(SM) 32–35MSI 500–700KSI

IntermediateModulus(IM) 42–43MSI 600–900KSI

HighModulus(HM) 50–65MSI 600–800KSI

Primary Source: ASM Handbook Vol.1 1 Source: USG DoE 13 Basic Steps in Carbon Fiber Production (PAN Precursor shown)

PAN Powder (Acrylic) Raw Material (powder) • Poly-Acrylic-Nitrile(PAN) goes through polymerization (turned into powder that will stick) oven • solvent is added to turn into a spinning dope. Precursor

Pre-curser(white fiber) Oxidation Carbonization • Dope is spun into fiber, washed, dried, & chemically treated. • Commercial pre-curser used only to make low end fiber (chop application). • high quality continuous ribbon Carbon Fiber Spool used to make aerospace quality. Sizing Surface Treatment

Carbon Fiber: Simplified, the process is heating and stretching precursor material through several oven stations ranging from 400F to 2500F. (Burnt String) Source: Boeing 14 Next – Creating the Product Forms

• Getting the fibers into the right place – Unidirectional (UD, or “Uni”) Materials – Tapes, Roving, Towpreg, Slit Tape – Woven Materials – Fabrics, Braids, 3D Weaves – Chopped Fibers (short) – Milled Fibers (very short) • Impregnating with resin – Prepregging by material manufacturer, or – Resin Infusion Processes (by part manufacturer)

15 Basic Steps in Pre-impregnation Process

Solution Coat Combi-Hot Melt/ Solution Coat Oven (B-stage)

Separation Film Metering Rolls “Blue Poly”

Carbon Fabric/Tape Prepreg

Resin Separation Film Bath “Blue Poly”

 One of two methods are used to impregnate the dry carbon fiber with polymeric matrix (resin).  Different matrices have different properties (toughening, etc).  Material is time and temperature sensitive after impregnation….must be kept frozen to maintain chemical and handling properties until cure.

Century Design9 16 Prepreg Material Time Limits (Boeing example) • Uncured composite materials typically have “shelf life” limits: – How long they can be refrigerated (frozen) – How long they can out of refrigeration, uncovered – How long they can be held, under a vacuum bag, before autoclave curing • Time limits are dependent on type of material. Typical example:

Supplier Inventory Purchaser Inventory Life 110 – 730 Varies from 280 – 1095 days Days (up to 3 years, dependent on material)

Date of Date of End of Manufacture Receipt Handling Mechanical Storage Life Life Life In 240 Hrs 1000 Hrs Freezer

Out of Layup Autoclave Storage Cure Start Complete, 17 Bagged Typical Prepreg Product Forms Aerospace Applications

Unidirectional Tape Unidirectional Tow Woven Fabrics • Typically 3”, 6”, 12” wide • Various narrow widths Typically 30” or 60” wide rolls • Most typically used with • Can be made by slitting tape Most typically used with hand automated layup • Always used with automated layup • Will follow contours layup • Various weaves – some have • Not typically used on outer • Several bands laid at once better drapability plys – drilling quality issues • Steerable (to a certain • Typically used on outer plys extent) – least drilling breakout • Not typically used on outer • Generates most scrap plys – drilling quality issues • More gaps/laps issues than 18 Boeing Photos with tape Tow, Slit Tape and Tape

0.125” 0.182” 0.500" 1" 1.5" 3” 6” 12” 0.157” 0.250"

Tow / Slit Tape Widths Tape Widths 19 Tape Width Drivers

Narrower Wider Surface contour/steering Knockdown for gaps Ply width increment

Crenulation fidelity Fly-away splices Buy-to-fly ratio Raw material cost* Spool/Roll length Head complexity

* Except for towpreg 20 What’s a Crenulation?

• Jagged excess left by 1.0” Excess Line (usually scribed on tool) automated layup Net Trim Line machines. – Machines trim ply courses at 90° to head travel. – Must layup so that there is full coverage of ply material.

Crenulations 21 Typical Fabric Weaves

Plain Weave (PW) Basket Weave Leno Weave 4 Harness Satin (4HS) Weave • Good fabric stability • Flatter, stronger than PW • Low number of yarns (AKA Crowfoot Satin) • Least pliable • Less fabric stability, more • Good fabric stability • Less fabric stability pliable than PW • Not often used for Aero • More pliable than PW • Good drapability

Warp Yarns (ply orientation Twill Weave 8 Harness Satin PX (Bias) Weave Direction) (8HS) Weave • Better fabric stability • Good fabric stability • Low fabric stability than satin weaves • Least pliable • Very pliable, drapable • More pliable than • Can eliminate • Only used on curved PW confusion of +/-45° Fill Yarns surfaces plys 22 Fabric illustrations ©2015 Hexcel Corporation. Reprinted with permission of Hexcel, further reproduction forbidden Textreme (Oxeon)

• Woven unidirectional spread-tow fabric materials

23 Dickson Photos • Quasi-Isotropic Reinforcement in a Single Braid Layer • Symmetric and Balanced with One Ply

0° (axial) -60° +60° (bias) (bias)

33% 33%

33% Uniform Stiffness In All Directions 24 Graphics – A&P Technologies11 Specialty/Decorative Weaves

25 Photos used by permission of CFA The Radius Filler or “Noodle” • Composite materials are inherently stiff – Sharp corners are avoided (not producible and structurally bad) • For certain types of geometry ( / back-to-back angles, I or J-shapes) a void is formed between the “halves” of the shape. The more plys in the laminate, the bigger the void • The void must be filled with material • Area is prone to quality issues Minimum Radius

Fewer plys More plys Smaller void Larger void 26 Smaller filler Larger filler “Noodle” former (radius filler)

• At simplest form, can be a hand-held die. • Automated machinery has been made - forms radius filler from folded tape – Material pulled through a die by machine

Source: Anon, “Accudyne Systems ships automated radius filler for B787”. Avail online: http://www.airframer.com/news_story.html?release=21989. Add’l info: http://www.accudyne.com/composites-automation/specialty-machines/%E2%97%8F-noodle-former-radius-filler.htm 27 Fiberglass

• Fiberglass prepreg has lots of aerospace applications in non-structural parts – Fairings – Radomes – Interiors parts • Non-aerospace: boats, car/truck bodies, windmill blades • Fiberglass plys are also used on composite laminates between carbon fiber plys and aluminum structure as an isolation patch to prevent corrosion. • Fiberglass has also been used for tool leak tests (2 or 3 plys cured on layup tool; leaks show as a starburst pattern on the cured plys)

28 Corrosion & CFRP

• Aluminum will corrode when in contact with CFRP • Certain fastener materials can also be inappropriate.

Mellema, Greg: “From the Ground Up: A Maintainer’sPerspective on Designing Composite Structuresfor Supportability”. 29 2016: SME Aerodef Conference Proceedings, Long Beach, CA. Dry (Unimpregnated) Product Forms

• Many traditional fabrics are available without added resin – No cold storage requirements • Typically used in “infusion” processes in aerospace, wet layup in other applications • Unique braided, woven product forms have been developed to address producibility issues.

30 Dry Fiber Products

31 Boeing Photos Woven preforms

• Complex woven shapes or flat shapes • Can have extreme drapability • Can make thick preforms Fiberglass Pi-Chord Preform

SAMPE images10 32 Braids • Braids typically a “sock” or “hose” – like form • Fibers both in axial or bias directions • Bias fibers can range from 10 to 80 degrees • No 90 degree fibers

Biaxial Braid Triaxial Braid

Graphics – A&P Technologies11 33 Braids • Braids typically a “sock” or “hose” – like form • Fibers both in axial or bias directions • Bias fibers can range from 10 to 80 degrees • No 90 degree fibers

Biaxial Braid Triaxial Braid

Graphics – A&P Technologies11 33 Discontinuous fiber products • Used on extreme contours/shapes wouldn’t allow other products to be used – Stretch-Broken Carbon Fibers – Cytec D-Form (mainly for Tooling)

Formed SBCF component 13

Cytec DForm™ 12 Slits in red

Pepin DiscoTex™ (SBCF)14

34 SAMPE Journal Vol. 51, no. 3 Non-crimp fiber products

• Fibers in traditional woven fabrics “crimp”. – Reduces load-carrying capability in direction Crimp Example of fiber • NCF fabric is created by stitching unidirectional layers together – Fibers not woven, no fiber crimp • Can have several layers stitched together

SAMPE Photo15

SAMPE Illustration16 35 Molding Compounds

• Short fibers compounded with resin for compression molding – Sheet Molding Compound (SMC) – Bulk Molding Compound (BMC) – Low mechanical properties • Randomly-oriented strips of unidirectional tape prepreg – HexMC from Hexcel

HexMCtm (and HexTooltm) Image courtesy of Hexcel

36 BMC (High Performance Composites)17 Demand by Product Form

HPC March 2013: http://www.compositesworld.com/articles/market-outlook-surplus-in-carbon-fibers-future 37 (Chris Red, Composites Forecasts & ConsultingLLC – Present. from CW Carbon Fiber 2012) Used by permission. Cores

• Cores are used to stiffen products, with the addition of only minimal weight • Aerospace cores tend to be honeycomb materials (lightest and most expensive) • Other products use balsa, foam & other unique cores • In-service problems with cores tend to be in areas where minimum gage laminates (few plys) are damaged or porous, allowing moisture to accumulate in core – Freeze/thaw cycles, corrosion, etc.

38 Honeycomb Core

• Various materials Coreorientation – Nomex®, Korex® aramid T – Thickness or cell depth L – Ribbon (or – Fiberglass longitudinal) direction – Polyimide/PAI W – Transverse direction d – Cell size – Graphite – Aluminum, etc – Ultem PEI Boeing • 1/8”, 3/16”, 1/4”, 3/8” cell sizes are typical • Core Densities 1.5 – 19.5 lbs/cu ft • “Ribbon” – directionality: core bends / flexes easily in transverse direction, stiff in ribbon direction • Typically milled to shape with valve stem cutter or formed – Edge chamfers – Contour 39 Common Aerospace Cores18

Face plys Film Adhesive

Hex Core

Core Flex Core

Face plys Film Adhesive Over-expanded Core Core can be milled or formed to shape 40 Other cores (Mainly non-aerospace) • Cores are available in product forms that are optimized for the process used (i.e. resin infusion or wet layup) • Cores used in infusion allow resin to travel along grooves & through holes to wet-out tool-side plys • Balsa Baltek Nida-Core Diab Rohacell • Foam Others – Rohacell has been used in aero structure • Soric – combination core & infusion medium (fabric- like) • Parabeam – non-traditional infusion product

Dickson photos 41 Core Stabilization

Grit Strip

Boeing Core problem19 Dickson Grit Strip Tiedown Method Photo Film Adhesive

•Prevent plys over Core Fiberglass core from slipping Core Prepreg •(Contributes to core crush) Film Adhesive Boeing Septum Method 42 Products for Lighting/HIRF Protection (HIRF-High Intensity Radiated Field)

• Metal airplanes – nearly entire airplane surface is very conductive; lots of ability to dissipate lightning strikes • Composites – special treatments are typically necessary to prevent lightning from creating holes in structure & penetrating fuel cells • Schemes allow conduction of current away from fasters • Interwoven Wire Fabric (IWWF) • Expanded Aluminum Foil • Sealing of “fay” (interfacing) surfaces, panel edges, cap seals on fasteners, etc.

Dexmet LSP Samples 43 Dickson Photos Part Engineering Drawings (and/or Specs) What you can expect to see: • Scale drawing or dataset showing ply boundaries • Ply orientation rosette • Splice requirements • Ply table • Core definition (if present) • Materials used • Quality requirements (dimensional, porosity, etc.)

44 Fabric Terminology & Ply Orientation 90° - 45° + 45°

0° Ply Orientation (ref) + 45° Typical Ply Orientation Rosette As-Scribed on Layup Tool ° 90° 0

- 45°

90°

45 Ply Splices • Splices may be required due to material size limits • Drawings don’t always say where to splice • “No Splice” areas usually noted • Splice Types – Overlap joints • Not allowed in faying regions or in filler plys • Often a .50” or less overlap – Butt joints • Often a .06” or less gap

46 Example Drawing

P5 P8 P6 P3 P7 P1, 3, 6, 8 P1

90° - 45° + 45°

Ribbon Direction 0° Ply Orientation (ref)

P2 View (Schematic, P4 P8 NoScale) P7 P6 P5 P4 P3 P2 P1 View (Schematic, 47 Dickson illustration NoScale) 47 Ply Drops and Padups

• In many cases, localized plys are added for load carrying purposes, increased thicknesses for fasteners, etc. • Plys are tapered (or dropped-off) gradually so as to not create riser or quality

problems Atypical

20 Henkel test panel with more extreme ply drops 48 Also on Dwg Balanced, Symmetric Layup Example Ply Table

Ply Orie Mat’l (Different Example) nt. 1 0° 1 Example Layup 2 +45 ° 2 • A balanced, symmetric layup helps 3 90° 4 - prevent laminate warpage 45° 5 0° • A balanced layup “balances” the off-axis 6 +45 plys (e.g.. equal numbers of +45° & -45 ° ° 7 90° ° ° or +60 & -60 plys) 8 - • 45° Not always possible in all areas of a part (e.g. 9 0°

where pad-ups exist) 10 +45 °

• A symmetric “quasi-isotropic” layup is 11 +45 °

common 12 0°

[0/+45/-45/90] [90/-45/+45/0] or 13 - 45° [0/+45/-45/90] s 14 90° 15 +45 – 25% 0°, 25% 90°, 25% +45°, 25% -45° ° – Isotropic in- only 16 0° 17 - • Quasi-isotropic: 180°/Number of ply 45° 18 90°

orientations that you need 19 +45 ° 2

° 1 Mat’l 1 callout: type, weight, Mfr. 20 0 49 1 49 2 Mat’l 2 callout: type, weight, Mfr. Issues that make parts warp

• Unbalanced laminate • Poor compaction/resin imbalance Less resin Bleeder cloth Lower CTE More resin Higher CTE Tool Warped part • Excessive Tool CTE on cool-down – Tool/ply friction – Ply/ply slippage

Unbalanced stresses Tool Growth in part causes warpage 50 Composites Processes

. Ply of Prepreg Materials . Hand Layup . Composites . Vacuum Bagging . Autoclave Curing of Composites and Out of Autoclave Curing OoA . Resin Infusion, Resin Transfer Molding, Resin Infusing Molding and Stand Alone Molding . Filament Winding

51 Steps in making parts from prepreg Record time Record time Record time

Pull prepreg Final Bag Layup Cure from freezer

Now Remove part from tool

Use Compaction Cut hand- or Debulk Trim laid plys Cycles Temp bag or Use Later Reusable bag

Kit & seal NDI for later use

Return to Freezer

Assembly 146 52 Ply Cutting

• Larger Shops use ultrasonic cutters – Gerber, AGFM, Eastman, others – Accuracies to .003” – Fast cutting Boeing photo – Integrated nesting to minimize waste • Many plys are cut by hand – Scizzors, “ wheels”, steel rule dies, etc. – only if backing material used

M Torres “Torresonic”32 53 Manual Cutting Methods

• Cutting devices – / Razor

Airtech Shop Shears21 – Hand held shears – Rotary (“Pizza”) cutter – Steel rule die • Most manual cutting devices are less accurate than automated methods • Allow “trim to fit” (cuts during layup) Various Cutters22 • Cuts should use backing boards • CAN DAMAGE TOOLS if done improperly. Durabledependabletools.com23 • Can lead to CTD injuries 54 Ply Cutting & Kitting

 Plys nested – minimize waste  Automated

 Plys kitted for layup  Doublers  Padups  Refreeze if not immediately used

54 Boeing illustrations 55 Hand Layup Boeing • Smaller aerospace parts, all boats, sporting goods all are done by hand layup • Plys that are cut to the right shape are placed, or “laid-up” in the right place and orientation • Very sensitive to process anomalies – mistakes, leaving extraneous materials in the laminate, poor technique, contaminants… • MUST do things correctly, per the drawing, per the process documents and the planning instructions. 56 Locating Plys

• Plys are most typically located by laser projection devices or by physical templates – Red or green lasers LPT, Virtek, Assembly Guidance, others • Templates are sometimes necessary, even when shop has a laser projector. – Tool fabrication, rework, maintenance costs Template with “Eyebrow” Cutouts Boeing photos 57 Layup Aids

• Shops typically have a palette of shop aids available – Sweeps – Silver pencils – – X-Actotm knives – Tapes – Gloves – etc.

Boeing photo 58 Tooling for Hand Layup

• Variety of materials available • Aerospace mfrs use Invar 36 for most production applications unless tool weight is an issue • Many varieties of composite materials • Steel, Aluminum, Nickel also used • Usually best to use best match with the CTE of the part Typical Aerospace ToolingMaterials

Steel, Nickel Can be exceptions! Alum, Steel, Nickel Invar or Carbon Fiber/BMI or Benzoxazine Production Prototype 3 ft 6 ft (Over) Foam, MDF, RP Materials GFRP Carbon Fiber/Epoxy 59 Composite Tools

• Composite materials primarily used for Outside Mold Line tooling applications (i.e. cover panels) • Most composite tools will require a master or pattern to lay up on. (HexTool product may not necessarily require them) • Eggcrate or tubular substructures • ~1/3 the weight of a comparable Invar tool • Longevity dependent on many things – how well they are made, how well they are treated in production, environmental conditions, etc.

OML IML Dickson photo 61 Composite Tool Examples

NONA Composites (CamX paper)24 Pic: Janicki Industries25

Boeing /Spirit Sect. 41 www.burnhamcomposites.com26 fuselage mandrel27 62 Invar Tools

• Tool size & shape dependent on part • Outside Mold Line & Structural Parts • Many tools will require 6” or more excess • Panel tools – eggcrate or partial eggcrates with tubular frames • Welding, machining & annealing processes • Billeted tools for smaller parts • Extremely durable – should last for over 1,000 cycles

63 Invar Tool Examples

Rib Layup Mandrel/Mold28 Nacelle Layup Mandrel/Mold (Coast Composites)29

RTM Die for Helicopter Rib (North Coast Tool & Mold)30 787 Wing Skin LM31 64 Vacuum Bagging

• Vacuum bags help compress or “compact” plys in the layup shop environment. • The bag, sealant tape, tool and fittings make up a system that has to be vacuum-tight, especially for liquid resin infusion processes. • Two main methods: – Consumable (throw-away) bags – Reusable bags

65 Rolls of Material

• Airtech • Cytec (former Richmond Aircraft Products) • Others? • Pre-kitted/pre-seamed bags available Boeing photo

66 Consumable Bags

• Bagging films – various materials, depending on application (nylon, kapton, etc.) • Pleats help ensure pressure transfer – Allow bag to be fitted to complex geometry

Pleat

67 Boeing Example Bagging Schematic (Prepreg parts)

Bagging Film

Breather cloth Consumables FEP release film SealantTape * Caul is reusable Peel Ply or caul * (optional) Laid-up Part Plys Tool

Typical Spec Diagram 68 Boeing Reusable Bags • Fabricated elastomeric bag • Fitted to part – eliminates pleating • Big time saver in production – Compaction & debulk cycles – Cure cycle

• Often have proprietary sealing methods Torr Mosites Rubber Bags48

Custom bag for NASA AST Wing46 “Sprayomer” Bag47 Silicone Bag (Smooth-On)49 69 DESIGN OVERVIEW AUTO-VAC (KEYHOLE SEAL W/PREFORMED BAG)

General Description • Vacuum bag de-bulking • Vacuum bag curing both autoclave and oven at 350 to 400 F and autoclave pressures up to 200 psi. • Vacuum Assisted Resin transfer Molding (VARTUM) used on medium to large FRP structures.

70 DESIGN OVERVIEW (KEYHOLE SEAL W/PREFORMED BAG)

New Tool Material Design Parameters

71 Design Overview (Keyhole seal w/Preformed Bag)

Eliminating Complexity of Vacuum Bag Fabricated Composite structures

)

TM RPBS TM showing a Wax Mock-up Auto-Vac with channel bonded onto of Final Layup 72 tool showing a completed part used for Mock-Up Materials

BP 102.080-G Uncured “B” Stage Elastermer .080” Thick (Grey)

BP 103 CH&K-05 BP 103 CH&K-05 Silicone Extrusion Silicone Extrusion Channel & Keyhole Channel & Keyhole ) Seal .250” Seal .500”

73 Vacuum Leak Detection

• Various methods – Listen for audible leak – Use stethoscopes, sniffers, etc – Static tests (measure vacuum loss over a Laco Hand-held Sniffer50 time period, e.g. 2” Hg loss in 5/10/20 mins. – dependent on tool size) – Helium leak check – Phenolphthalein leak test – 2 or 3 ply fiberglass prepreg layup/cure

Ultrasonic Leak Detector (DeComp Composites)51 74 Compaction & Debulk

• For thick laminates, even transfer of pressure can be difficult. – Potential issues: Ply bridging, resin richness/starvation, etc. • Intermediate steps often taken in layup: – Ply compaction – bag the plys and let it compress under vacuum (some times as often as every two plys) – Hot debulk: bag the part, heat it and let it compress (lower temperature than cure temp), e.g. 200°F for 350°F curing prepreg (done much less often than RT compaction)

75 Autoclave Cure

• Parts cured per a spec – Heatup requirements – Dwell requirements – Cooldown requirements Convergent, inc.52 – Parts monitored by thermocouple and vacuum level • Watch for exotherms • Often a nitrogen atmosphere is used in autoclave Dickson photo – Prevents fires from exotherms, etc. – Some sealant tapes actually perform better in nitrogen (foaming prevention) • All autoclaves are not created equal (P, T)

76 MHI – 787 Wing Skin53 Out-of-Autoclave (OoA)

• Resin Infusion processes (some may still use Autoclaves) • Oven Cures – May use specially-formulated prepregs • Stand Alone Cures – Integrally-Heated Tools

Advanced Composite Cargo Aircraft91 77 HPC Jan 200854 Resin Infusion

• Typically, a dry preform is laid-up, placed under a vacuum bag and mixed resin is drawn into the preform. • Many different variations to this, with numerous patents involved.

78 Steps in making parts infused parts

Install Draw Mix Resin, Layup Consumable Vacuum Infuse & Items Cure Remove part Peel ply, from tool Resin Distribution Media Create Vacuum Lines Trim Preform Resin Distribution Lines Vacuum bag Stitching A/R, Add Tackifier

NDI

Assembly 79 Creating the Preform

• Methods used typically depend on part complexity • Simplest – cut plys and place them on mold in correct position, typically with a sprayed tackifier • Often use Non-Crimp Fabrics (NCF) for rapid ply buildup • Complex – stitch plies together to form integral stiffeners, etc.

80 Robotic Ply Placement for Automotive Applications • Most typically for Resin Transfer Molding (RTM) applications: – Plys are nested and cut – Plys are located by “pick and place” operations – robots with vacuum or needle gripper end effectors

Schmalz Grippers55 81 Pinette Emidicau Robotic RTM Cell56 Large Preforms → Large Parts

Latecoere Passenger Door57

NASA AST Wing Preform58 82 Some of the Processes (everybody’s got an acronym) • CAPRI (Boeing) – Controlled Atmospheric Pressure Resin Infusion • RTI (Bombardier) – Resin Transfer Infusion • SCRIMP – Seeman Composites Resin Infusion Manufacturing Process • VaRTM – Vacuum-assisted Resin Transfer Molding • VIP – Vacuum Infusion Process • VAP (Airbus) – Vacuum-Assisted Process

83 How Resin Infusion Works (typical simplified schematic)

Peel ply over part

Resin Vacuum Resin Advancing Distribution Pump Trap Resin Media Flow Approx 16 “ Front or so apart

Unclamped Vacuum Resin Line Line Around Periphery Clamped-off Mixed Resin Lines Resin 84 How Resin Infusion Works (typical simplified schematic)

Peel ply over part

Resin Vacuum Resin Advancing Distribution Pump Trap Resin Media Flow Approx 16 “ Front or so apart

Unclamped Vacuum Resin Line Line Around Periphery Unclamped Mixed Resin Lines Resin 85 Notes on Infusion Media

• Infusion materials (throw- away) – Round tube for resin – Spiral-cut tube for vacuum – Omega shapes and other various media for resin distribution

• Some products (plastic Dickson Photo netting) used in lieu of breathers

86 Resin Transfer Molding (RTM)

• Preformed plys are placed in a (very expensive) mold and resin i is injected and cured. • Matched mold halves are often held in a press • Molds machined to close tolerances • Often liquid-heated (oil or pressurized water)

• Fast cycle times – less than 30 59 minutes typically Pics – North Coast Tool & Mold

87 88 Aerospace RTM Part Examples

Hexcel/Eurocopter A350 HTP Leading Edge A380 Hinge Fitting60 One-shot RTM Sine Wave part61 Aernnova60 Comparable Metal Part

757 Door Radius SQRTM Roof Panel (HPC)63 Latecoere A350 Door64 89 (Boeing Photo) Light-RTM

• Closed mold system – one side is hard tool, other is semi-rigid (~8 plies fiberglass mat). • Resin drawn into preform by vacuum; may be assisted by a pump (2psi).

Vacuum Resin Vacuum (clamp) injection (clamp)

65 Fabric Preform Reinforced Plastics 90 Figure 1 shows the process of the vacuum pulling the resin from the external reservoir into the part. It also shows the position of the RDM and vacuum bag as indicated by the arrows..

Figure 1 Schematic of the VARTM Process (Reference 7) 91 Project Title: Stitched RFI Stitched Preform

• Material- carbon fiber warp-knit hybrid • Preform size- 10’ x 5’ • Skin thickness- 0.072” • Vectran thread

92 Project Title: Stitched RFI Resin Tile Installation

• Resin tiles placed on IML side in each bay (vs. OML) • Resin material: Hexcel 3501-6 RC

93 Project Title: Stitched RFI Cured Part

• Success Criteria: +/-0.030”on stiffener location • 100% of 238 stiffener data points taken by laser tracker were within +/-0.030”!!! • Next step- Ballistic Test! 94 Stand-Alone Quickstep • Unique process that uses a “heat transfer fluid” and “floating mold technology” to cure parts.

“Floating Mould”62

95 Curing Chamber66 Stand-Alone Windmill Blade Mold • Molds use hot liquid channels, electrical heating cables or blown hot air to cure parts. • Size typically can require powered hinge system

CW Cover Photo67 LM Glassfiber (CW)68 96 Resin Film Infusion (RFI)

• Gelled, cast resin tiles are placed on the tool and preform placed over the tiles • Part is bagged and heated in autoclave. • Resin liquifies and wicks into the preform.

NASA AST Wing Project (SAMPE)69 97 Debag & Tool / Part Separation

• Consumables (bag, breather, tape, etc) are removed and disposed-of. • Part must be removed from tool CAREFULLY – Don’t want to damage tool or part – Use relatively soft tools to assist • Phenolic or plastic wedges • Wooden tongue depressors around periphery • Work around tool until the part breaks free • In some cases, features designed-into the tool may offer good assistance – Threaded holes in stiffener mandrels – Cavities for wedges – cure over the wedge in part excess.

98 Thermoplastics

• Thermoplastics are used mainly for secondary structures and Interiors in aircraft • Significant research in Europe for using T/Ps for more and more structure – TAPAS: Integral tail structure – Airbus: In-situ layup/consolidation of fuselage barrel structure • PEEK, PEKK, PPS, PEI in Aerospace • PP, PA, PBT/PET, PPS in Automotive

99 Benefits of Thermoplastics

• Very fast cycle times for some applications – Press cures: low labor cost • Ability to re-melt & re-form • Can be welded • Easy to recycle • Drawbacks are mainly material cost & high processing temperatures (600 – 700°F).

100 Press-Forming of Thermoplastic Parts

Pre-Heat Thermoplastic Composite Sheet

Stamping Press

Die typically has a steel half and an elastomeric half

101 Welding of Thermoplastics

• Ultrasonic welding (localized areas, e.g. inserts) – think “spot welding” • Resistance Welding – a “weld strip” is placed within the part-to-part interface and is heated. • Induction welding – a magnetic field induces current in the carbon fiber, creating heat

102 Part Trim (Thermoset or thermoplastic parts) • Parts in most cases are trimmed net • Sometimes fastener holes are drilled while on the same tool • Typical methods: – Hand-held router with a guide – Pin shaper with a guide – Multi-axis NC router – Multi-axis waterjet/ waterjet

103 Small Parts – Trim with Routers and Pin Shapers • Edge of router fixture tool is used to guide the router • Router shoulder also rides on tool – ensures 90 degree cut • Requires skilled labor – easy to gouge-up the part

Tool Part

104 Boeing Large Parts – Trim with NC routers • Various styles of tool – may allow gage reduction/ milling

Boeing photo & illustration

Want to contain/capture the dust!

105 Thermwood 5-axis composite router70 Cutters for composite trimming • Carbide cutters (short life) • Various grades of diamond coatings • PolyCrystalline Diamond (PCD) Coatings – very durable • Various geometries

Robbjack, Inc.71 Carbide Diamond-Coated PCD-Coated 106 Large Parts – Trim with Automated Waterjet • Edge trim and cut-outs (doors, windows, etc.) • Often use Universal Holding Fixtures (next slide) • Very powerful stream of high-pressure water, with or without garnet abrasive particles

Flow73 107 Omax72 Universal Holding Fixtures

Micado “Snake System” Micado “Hedgehog” 74 Micado “Pogostick Gantry” (Repositionable Posts)74 (Passive pogos) 74

M Torres “TorresTool” – example configurations75 108 Assembly

• Traditional assembly involves “drilling Drill Jig (Boeing) and filling” – drill holes for fasteners, disassemble and deburr parts, shim parts & wet-install fasteners. • Some technologies (e.g. orbital drilling) may eliminate the deburr operation. • Co-curing or co-bonding parts can Orbital Drilling eliminate many downstream assembly operations, related tools and drilling equipment.

109 Boeing graphics Latecoere A350 Door Some Assembly Considerations

• Fabric is typically used on outer plys to help prevent drilling breakout • Fiberglass isolation plys are used where carbon and aluminum would otherwise be in contact (corrosion prevention) • Airplane wings typically carry fuel – sealing and the lightning protection scheme are of critical importance!

110 Drilling Composites

Slide Credit: Chris Eastland 111 Boeing photos “Mainstream Production” vs “One- off”/ ”Prototype” • The same approaches are typically not used for prototyping vs. serial production unless you already have the equipment (tape layers, fiber placement machines, etc.) • The place where corners may be cut is in the tooling (NEVER cut corners on production tools), but there will be trade-offs – Dimensional integrity – Warpage – etc

112 Composite Materials for Prototyping

• Materials that cure at low temperatures allow higher CTE tooling materials to be used. • Examples: • Cytec LTM-series – can do initial cures at 140°F – Elevated free-standing post cure necessary (i.e. 15 min @ 392°F then 8 hrs @ 375°F – Infusion resins • RenFusion 8615: 24 hrs @ 77°F, 4 hrs @ 250°F, 4 hrs @ 350°F • NONA – cures by it’s own exotherm • Expect trade-offs!

113 Examples of Prototype Tooling

• Layup/cure: – Plaster/Bondo – Wood/MDF – Foams from General Plastics, Coastal Enterprises, Stepan, etc – Cfoam carbon foam with surface filler – Additive Mfg materials (FDM Ultem) – REN RP4040 “LCTC” patties over alum. honeycomb – Aluminum rather than Invar • Trim: – Foam with a vacuum chuck or hold part with drywall screws in part excess or with double-back tape – Additive Mfg materials (e.g. SLS Nylon or FDM ABS) – Hand layout/hand trim with straight edge guide • Assembly – Layout holes with mylar plot and hand drill – Use metrology assist (Laser Tracker)

114 Planes, Blades and Automobiles

• Quick overview of how parts are made

115 Fabrication of Composite Aircraft Structure

Upper Panel

Spars (2 or more) Ribs Stringers (various types!)

Lower Panel Rib Posts (at each rib/spar joint)

Dickson illustration 116 Shear Ties (upper & lower at each rib) A few Examples of Production Curing Methods Composite Aircraft Wing Skins • Co-bond – Pre-cured stringers with uncured panel

• Reverse-Co-bond – Pre-cured panel with uncured stringers

• Resin Transfer Infusion – Resin infused into panel and stringers through stringer caps – Co-bonded vent stringers (hats)

117 Stringers

• Stringer geometry (i.e. “hats” “blades”, “I’s” or “omegas”) can be a determining factor of cure method and tooling concept. • Drape forming, roll forming, press forming commonly used prior to cure. Caul Bladder

IML Tool Surface OML Tool Surface Cure Tool Dickson illustration 118 A few Examples of Production Curing Methods Composite Aircraft Wing Spars • Hot Drape Forming most common – Uni-tape laid flat, then formed to channel shape under heat and bladder pressure

• Other methods (mostly studies): – Automated Fiber Placement – OoA Prepreg – RTM

Dickson illustration 119 A few Examples of Production Curing Methods Composite Aircraft Fuselages • One Piece Barrels – AFP & Co-cure of stringers and skins on IML tooling • Build-up from panels – AFP & Co-bond cured stringers and uncured skins on IML tooling – Some smaller airplanes have used hand layup and honeycomb-stiffening

• Studies – OoA prepregs, Resin Infusion

120 Honeycomb-Stiffened Parts

• Most typically hand layup • Autoclaved cures, 350°F at 45-60 psi • Ribs, control surfaces (e.g. flaps, ailerons, rudders, fairings, etc.) • Control surfaces can be multi-stage cures due to having complex components in a bond assembly (spars, fittings, close-out ribs, etc.)

Dickson illustration 121 Future A/P Fabrication

• EU research: thermoplastic fuselages & wings – (TAPAS, FUBACOMP, FUSCOMP, other “Framework programmes”) • Use of more OoA technologies (prepregs, RTM, VaRTM, integrally-heated tools, etc)

122 TAPAS Thermoplastic Helicopter Stabilizer (Dickson JEC show photos) Wind Generation

• Due to size, processes rely on resin infusion and OoA cures • Traditionally fiberglass with foam, balsa cores in skins and foam cored spars

Dickson JEC show photos 123 Wind Generation

• More recently – use of Non-crimp fabrics – Glass/Carbon/Aramid hybrids • Faster laydown rates • As blades get larger, more carbon will likely be necessary • More layup automation – Fives Cincinnati, Danobat, M Torres, others

124 Autos

• Big push to drive down cost – Carbon Fiber: • BMW with SGL • Ford with DowAksa • ORNL low cost carbon BMW I3 at JEC 2013 – Production efficiency • Plasan 16 minute cures on Corvette hoods – Globe “Rapid Claves” – BMW automated preform handling for RTM

Dickson photo 125 Bikes

• Prepreg plys cut • Layup in a female mold with a bladder • Mold closed & placed in a press • Bladder is pressurized • Part is cured & demolded • Fittings are secondary-bonded

Trek Bike pictures courtesy of High Performance Composites90 126 End of Life: Recycling

• Thermoplastics are the easiest to recycle • Thermosets are most often used. • Thermoset recycling most often means separating fiber and resin (cured or uncured) – Pyrolysis, Fluid Bed Oxidation, Solvolysis, etc. • Long fiber products become short fiber and recombined with resin (molding compounds, etc.) • Development work: fiber alignment

127 https://www.youtube.com/watch?v=-ZQzfwdHf1I Filament Winding Process

• Types of Filament Winding Machines – Tube Winders – Longo Winders – Complex Shapes 3 or more – Ring Winder

128 Pros and Cons of Wet Filament Winding verses Prepreg Winding • Pros – Cost of materials – You control the quality of the fiber impregnation – No storage of prepreg material and worry about material running out of date. • Cons – Some feel it saves time using prepreg material

129 Wet Filament Winding For Process Control

130 Three Axes Filament Winding Machine With Fiber Impregnation On Machine

131 Filament winding of outer skin using Prepreg fibers

132 Filament Winding Machine - Winding Spar Tube

133 Race Track Winder Manufacturing spar caps For Composite Main Rotor Blade

134 Race Track Winder – showing resin impregnation of fibers

135 Filament winding of prepreg spar cap

Spar cap assembly

136 137 Four axes electrically driven computer controlled unidirectional fiber placement machine with 16 rotating fiber spools

Manufactured by Century Design

138 Tooling and Filament Winding Process This filament winding machine has 5axis

139 Ring Winder – A developmental machine with a stationary mandrel and rotating fibers

140 Machine Layup

• Prepreg Tape, Slit Tape, Towpreg or Roving is laid-down in a pre-determined orientation by automated machines • Flat tape laminators (3-axis) • Contoured tape laminators (5-plus axes) • Automated Fiber Placement (AFP) machines • Automated Filament Winders (sometimes uses wetted- out roving) • Pultrusion machines • Typically the machines come in a number of configurations/sizes/etc.

141 Machine Layup

• Machine layup is most effective when they can lay-down very long courses of material, uninterrupted – Starts and stops for short courses reduce effectiveness • E.g. 90 and +/-45° plys on long, narrow parts • Name of the game is lbs/hr in laydown – Varies considerably with complexity of part design and basic geometry – Traditional machines anywhere from 5 – 25 lbs/hr – Machine mfrs working to move this closer to 100 lbs/hr

142 Automated Tape Layers

M Torres32

Fives Cincinnati machine At Exelis33

777 Skin Panel Layup (Boeing photo) 143 Automated Fiber Placement More traditional machines

Ingersoll – Vertical35 Ingersoll – Horizontal (787 Alenia)36

ElectroImpact37 144 Fives Cincinnati34 Methods of Fiber Delivery

Spools at head Central Creel-house

M Torres Photos32

145 Relatively new – Automated Fabric Laydown (for infusion processes)

Fives Cincinnati Rapid Mat’l Placement System M Torres Wind Blade System (CompositesWorld38) (CompositesWorld38)

Danobat – Gelcoat Application (SME Composites Mfg 2012)39

Engineering TV Video (Fives Cincinnati machine) http://www.engineeringtv.com/video/Automating-Wind-Turbine-Blade-F 146 Robotic AFP Machines

Coriolis Composites40 Fives Cincinnati “Robotic Viper”41

ElectroImpact42

147 Automated Dynamics43 What’s next? Robots working in unison

DLR Center for Lightweight M Torres Robotic ATL Cell32 Production Technology GroFi Platform44

148 Tools for Automated Layup

• Tool designs must consider how the tools will be indexed to the automated layup equipment, plus any special load cases – Rotating tool supported by spindles? – Special load cases: dynamic frequency, emergency stop – Types of indexes required

149 Purpose-Built Machinery

• Large Airframers and Sub-contractors often build unique equipment to perform layup and other functions. • Example: ATK Stringer & Frame formers

Hooper, et al (SAMPE)45 150 Tool Preparation

• Tools are routinely cleaned before/after each use – Remove resin flash, tape residue, etc. • Tools are treated with a sealer before each use and after stripping release coat buildup • Tools are very often treated with release coats before each use.

151 Non-Destructive Inspection (NDI)

• Laminates can be checked by various methods – Visual inspection – Tap tests – Large “monument”-type NC-driven Ultrasonic Testing (UT) machines very common in aerospace – Conventional and digital X-ray – Numerous types of hand-held devices – Pulse-echo, Laser shearography, Flash thermography, FTIR, etc • NDI devices are calibrated by “Standards” – Sample parts with a known flaw

152 Visual Inspections

• Should be able to find: • Warpage • Obviously crushed core • Surface Anomalies (resin richness/starvation, sink marks, etc.) • Surface wrinkles • Cracks, delaminations, etc. • Obviously mislocated details (stiffener migration, etc.)

153 Monument-type NDI Equipment Typically $Millions for larger equipment • Ultrasonics (e.g. TTU, AUSS, Laser UT, etc.) – Various configurations, many have specially- designed arrays, transducers or sensors

Immersion Gantry Robotic Water-coupled • X-Ray (conventional or digital) (SAMPE76)

154 Boeing photos, except as noted Hand-held NDI Equipment Increasing sophistication and cost • Tap Hammer / Quarter

• Calibrated Tap Hammer Mil-spec tap hammer77 Digital tap hammer78

• Pulse-Echo

Olympus Boeing81 Quantum UT79 • Bond Testers OmniScan80

• FTIR

Olympus ImperiumAcousticam84 BondaScope82 Bondmaster83 155 <-Agilent FTIR85 Types of Ultrasonic Scans

• A-Scan: Ultrasonic pulse will show that there is a defect, displayed as a simple wave form showing amplitude vs time. Signal reflects either off the opposite side of the part (long amplitude) or off an anomaly (shorter amplitude)

• B-Scan: Multiple A-scans along a line

B-scan of wrinkle (single line) • C-Scan: Records the A-scan and displays the plan view of defect boundaries (an image)

Boeing photos C-scan of wrinkle plan view 156 Many Devices Use All Three

B-scan Along Line Trace of C-scan

Boeing photos 157 What do we look for? Some common types of Laminate Anomalies

Disbonds, Delaminations, Porosity Wrinkles Cracks

Voids (>.25 in) Inclusions (e.g. backing poly) Ply bridging

Boeing photos 158 Boeing In-service Issues Production Issues photos (X Water - ray image) in core cell Core Anomalies Crushed core 159 In-Service Issues

• Examples of types of damage composite parts might typically experience

160 Aircraft - FAA

Used by permission 161 Aircraft - FAA

Used by permission 162 Aircraft - FAA

Used by permission 163 Automotive Damage

10 inch crack to Fender Liner Driver’s side door rocker channel impact damage

164 Pictures courtesy of Lou Dorworth, Abaris Training. Used by permission. Automotive Damage

10 inch crack to Fender Liner Driver’s side door rocker channel impact damage

165 Pictures courtesy of Lou Dorworth, Abaris Training. Used by permission. Windmill Blade Damage

North American Windpower pic86. Daily Mail (UK) pic.87

88 89 London Express CompositesWorld 166 Repairs

• First step – decide whether its easier/more cost effective to replace the part rather than repair – You often have to deal with or at least work-around underlying structure • Repairs typically involve inspecting, removing the damage and restoring the damaged plys – Want to maintain close to the same strength & stiffness as the original part • Extent of the repair depends on the extent of the damage

167 Picture: CompositesWorld89 Typical Repairs

• Bolted – Repair patch is bolted to the damaged area • Cosmetically poor; may be OK in areas out of airstream • Bonded

– Step-cuts • New – robotic and applieddevices that mill steps

– Scarf cuts (<10° taper sanding) • Skilledtech’s with rotary grinder, e.g. Dotco – Plies cut to shape, compacted, applied with a caul and cured with heat blanket – Plies follow same orientation as original plies

168 Boeing graphics Class Summary

• Materials – resins & reinforcements • Processes – layup, trim, assembly • Automation • Inspection (in-factory and in-service) • Repairs • Applications – aerospace, wind, automotive Recycling

169 170 171 Photo & Illustration Credits

1. Boeing 787 photo, courtesy of The Boeing Company 2. BMW i3 – Dickson photo 3. Anon: “Wind Turbine Blades: Big and Getting Bigger. June 2008: Composites Technology. Article avail. Online: www.compositesworld.com/articles/wind-turbine-blades-big-and-getting-bigger Cover photo: http://www.compositesworld.com/articles/archive/863d0bd5-e4a5-42cc-a6a4-cc3583bfc0d1 4. Blackbird “Super OM” Guitar: www.blackbirdguitar.com Used by permission. 5. Misc. Sporting goods: Dickson photos 6. BMW/Oracle America’s Cup Yacht: Anon. “America’s Cup 34”. Sept 23, 2013: Seattle Times. Avail online: http://www.seattletimes.com/news/americas-cup-34/ 7. Carbon fiber: en.wikipedia.org/wiki/Carbon_%28fiber%29 8. CF Oxidation Line: Anon. “Complete Carbon Fiber Process Lines from Harper”. April 7, 2011. Avail online (video): https://www.youtube.com/watch?feature=player_embedded&v=W16JJw0fFjQ 9. Century Design Hot Melt Prepreg Equipment: www.centurydesigninc.com. Used by permission. 10. 3Tex woven preforms: Heider, D, et al. “ Large-Scale Joint Fabrication Using 3-D Fabric Preforms, Sandwich Core Structure and VARTM Processing”. SAMPE Sept/Oct 2008, Vol 44, No. 5. Also - Bogdanovich, A, et al. “Fabrication of 3-D Woven Preforms and Composites with Integrated Fiber Optic Sensors”. SAMPE 2003 Conf, Long Beach, CA, May 11-15, 2003. SAMPE Journal, Vol. 39, No. 4, July/Aug 2003, pp. 6-15. Additional info on 3D weaves: www.3Tex.com 11. Braid pictures and illustrations: A&P Technologies. www.braider.comUsed by permission. 12. Illustration and component fabricated from Cytec Dform material: http://www.cytec.com/dform/. Images courtesy of Cytec, Inc. 13. Test component fabricated from Stretch Broken Fiber: Dillon, Gregory & Stiver, Donald: “Application of Stretch Broken Carbon Fiber Materials to Rotorcraft Structures”. 2006, Vol. 51. Society for the Advancement of Material & Process Engineering (SAMPE). 14. DiscoTex Stretch Broken Fiber: Ng, Stanley and Meilunas, Raymond: “Aligned Discontinuous Carbon Fiber forComposites Forming”. 2007, Vol. 52. Society for the Advancement of Material & Process Engineering (SAMPE). Additional info: www.pepinassociates.com/DiscoTex.html 15. Non-CrimpFiber Fabric Image: Bischoff, T, et al. “Multi-Axial Fabrics – Near Net Shape Preforms for Advanced Composite Structures”. 2005: SAMPE – proceedings of 37th ISTC conference. Additional info: Saertex, inc. www.saertex.com 172 Photo & Illustration Credits

16. NCF image: Dobrich, O, et al. “A Novel Technology for Manufacturing Non-Crimp Reinforcement Fabrics forComposites ’. 2014: Sampe Conference proceedings. Add’l info : www.saertex.com. 17. BMC: Black, Sara. “Redesigning for simplicity and economy”. 2012: High Performance Composites. Avail online: http://www.compositesworld.com/articles/redesigning-for-simplicity-and-economy 18. Core illustrations: Dickson 19. Crushed core cells: Boyd, J and Maskell, R. “Product Design for Low Cost Manufacturing of Composites for Aerospace Applications”. 2001: Proceedings of SAMPE Conference, Long Beach, CA. 20. Henkel Test Panel: Floryancic, Bryce, et al: “Development of Void Free Out of Autoclave (OOA) Benzoxazine Prepreg Systems for High Toughness and High Temperature Applications”. 2014: Society for the Advancement of Material & Process Engineering (SAMPE CamX Conference Proceedings). 21. Airtech Shears: www.airtechonline.com. Used by permission. 22. Various cutters: Dickson photo. 23. Steel rule die: www.durabledependabletools.com 24. NONAcomposite LM: Dietz, Ben: “No-Oven, No-Autoclave Composite Tool Fabrication”. 2014: Society for the Advancement of Material & Process Engineering (SAMPE CamX Conference Proceedings). 25. Composite tool with steel substructure: Used by permission of Janicki Industries. www.janicki.com. 26. Truss-type composite tool: Burnham Composites, Wichita, KS. www.burnhamcomposites.comUsed by permission. 27. Boeing 787 Fuselage Cab Fiber Placement Mandrel: Drew, Christopher and Mouawad, Jad. “New Challenges for the Fixers of Boeing’s 787”. NY Times. Avail online: http://www.nytimes.com/2013/07/30/business/boeings-787-poses-new-challenges-for-repair- teams.html?_r=0 28. Rib Layup Mandrel: Boeing image 29. Nacelle Mandrel: Courtesy of Coast Composites, an Ascent Aerospace Company (www.coastcomposites.com).Used by permission. 30. Resin Transfer Molding Die : Dickson photo (SAMPE conference display) Additional info: www.nctm.com

173 Photo & Illustration Credits

31. 787 Wing Skin Mandrel at MHI. Boeing photo 32. M Torres photos of Tape Layers, Fiber Placement and Ultrasonic Knife: M Torres proprietary photos. Add’l info: http://www.mtorres.es/en/aeronautics/products/carbon-fiber/torreslayup. Used by permission. 33. Fives Cincinnati Tape Layer at Exelis: Sloan, Jeff. “Exelis Aerostructures: Salt Lake City”. 2015: CompositesWorld. Avail. Online: http://www.compositesworld.com/articles/exelis-aerostructures-salt- lake-city. Used by permission. 34. Fives Cincinnati AFP equipment: Anon. “Vertical gantry fiber placement system”. 2012: High Performance Composites. Avail online: http://www.compositesworld.com/products/vertical-gantry- fiber-placement-system . Used by permission. 35. Ingersoll AFP machine at Goodrich: Sloan, Jeff: “ATL and AFP: Signs of evolution in machine process control “. High Performance Composites, Sept 2008. Avail online: http://www.compositesworld.com/articles/atl-and-afp-signs-of-evolution-in-machine-process-control. 36. 787 Fuselage barrel section layup at Alenia: Boeing photo 37. Electroimpact AFP machine and mandrel: Ehinger, Peter, et al. “Implementation of Non-Contact Drives into a High-Rail, 7-Axis, AFP Motion Platform”. 2013: Proceedings of SAE Aerotech Congress. Avail. online: www.electroimpact.com/WhitePapers/2013-01-2288.pdf 38. Windmill Blade Automation: Black, Sara. “Automating Wind Blade Manufacture”. 2009: Composites Technology. Avail online: http://www.compositesworld.com/articles/automating-wind-blade- manufacture 39. Danobat automated equipment for gel coat application on windmill blades: Maas, David. “Automated Dry Fiber Placement for Very Large, High Throughput VARTM Composite Applications”. 2012. Proceedings of SME Composites Conference, Mesa, AZ. 40. Coriolis robotic AFP: Grant, Carroll. “Composites automation: Trending smaller and robotic“. 2012: High Performance Composites. Avail online: http://www.compositesworld.com/columns/composites- automation-trending-smaller-and-robotic. www.coriolis-composites.com 174 Photo & Illustration Credits

41. Fives Cincinnati robotic “Viper” AFP cell: (see source 40). Avail online: http://www.compositesworld.com/columns/composites-automation-trending-smaller-and-robotic. Add’l info: http://metal-cutting-composites.fivesgroup.com/products/composites/composites- systems.html. Used by permission. 42. Electroimpact AFP machine and mandrel: Faubion, Guy and Wells, Dan. “Highly-Flexible Automated Carbon Fiber Layup Cell for Manufacturing Wide Variety of Carbon Fiber Parts”. 2014: Defense Manufacturing Conference (DMC). Avail. online: https://www.electroimpact.com/WhitePapers/EI_DMC_2014_Presentation.pptx 43. Automated Dynamics robotic AFP equipment: Anon. “Automated Dynamics wins fiber placement contract with U.S. Navy”. 2012” CompositesWorld. Avail online: http://www.compositesworld.com/news/automated-dynamics-wins-fiber-placement-contract-with-us- navy. Add’l info: www.automateddynamics.com 44. DLR (German Aerospace Institute) GroFi robotic layup cell: Krombholz, C. et al. “Advanced Automated Fiber Placement”. Cranfield, Bedfordshire, UK: Proceedings of the 11th International Conferenceon Manufacturing Research (ICMR2013). Also: “GroFi - Combining automated fiber placement (AFP) and automated tape laying (ATL) on a flexible production plant by means of simultaneous working, robot based layup units” Additional info: http://www.dlr.de/fa/portaldata/17/resources/dokumente/publikationen/grofi_handout.pdf ATK Stringer and Frame cells: Hooper, et al. “Advancements in Automated Fabrication and Inspection of 45. Aerospace Grade Composite Structures”. 2014: Society for the Advancement of Material & Process Engineering (SAMPE CamX Conference Proceedings). Custom bag for NASA AST Wing project: Thrash, Patrick and Ghumman, Aaron: Manufacture of Stitched 46. Resin Film Infused Carbon Fiber Epoxy Wing Cover Panel. 1999, Vol. 52. Society for the Advancement of Material & Process Engineering (SAMPE). Sprayomer™Technology spray on vacuum membranes/bags by SR Composites, LLC, U.S. Patents 47. 8,916,073 & 8,672,665 Other U.S. & International Patents & Patents Pending. Add’l info: http://www.srcomposites.com/. Used by permission. 175 Photo & Illustration Credits

48. Torr Technologies reusable elastomeric vacuum bags: http://www.torrtech.com/Pages/index.html 49. Smooth-On reusable silicon vacuum bags: Black, Sara. “Reusable vacuum membranes: Coming of age?”. 2013: Composites Technology. Addl info: http://www.smooth-on.com/Vacuum- Bagging/c1334/index.html 50. LACO Technologies Handheld GasCheck Sniffer Leak Detector: http://www.lacotech.com/leaktesting/handheld-leak-detectors/handheldgaschecksniffer.aspx. Used by permission. 51. De-Comp Composites ultrasonic vacuum leak detector: http://decomp.com/product/d9140k-leak- detector-kit/. Used by permission. 52. Example autoclave trace : Convergent Manufacturing Technologies. Add’l info: www.convergent.ca. Used by permission. 53. 787 wing skin mandrel in autoclave at MHI in Japan: Boeing photo 54. Integrally-heated mold: LeGault, M. “Tooling Update: New Dimensions in Tooling”. 2008: High Performance Composites. Avail online: http://www.compositesworld.com/articles/tooling-update-new- dimensions-in-tooling. Additional info: www.weberman.on.ca. 55. Schmalz composite grippers: Katz, Justin. “Handling Technologies for the Automated Production of Composite Parts”. 2014: Proceedings of the SME Composites Manufacturing 2014 Conference. 56. Pinette Emidicau robotic RTM cell: Anon. “Pinette Emidecau reveals details of high-speed RTM cell”. 2013: CompositesWorld. Avail online: http://www.compositesworld.com/news/pinette-emidecau- reveals-details-of-high-speed-rtm-cell. Add’l info: http://www.pinetteemidecau.eu/en/ 57. Latecoere aircraft door : Sloan, Jeff. “Integrated, Optimized Aircraft Door”. 2012: High Performance Composites. Avail. Online: http://www.compositesworld.com/articles/integrated-optimized-aircraft- door 176 Photo & Illustration Credits

58. NASAAST wing project preform and finished panel: Thrash, Patrick and Ghumman, Aaron: Manufacture of Stitched Resin Film Infused Carbon Fiber Epoxy Wing Cover Panel. 1999, Vol. 52. Society for the Advancement of Material & Process Engineering (SAMPE). 59. Resin Transfer Mold and molded rudder structure: Evanovich, Jay. Out-of-press resin transfer molding of the G250 rudder. 2011: Proceedings of the SME Composites Manufacturing 2011 Conference, Dayton, OH. Add’l info: North Coast Tool & Mold. www.nctm.com 60. Aernnova A350 RTM structure &Hexcel/Eurocopter A380 Hinge Fitting (2013 JEC Show, Paris): Dickson photo 61. VAP infused Sine-Wave part: Anon. “Premium AEROTEC, Boeing demonstrate composite wing technology”. 2012: CompositesWorld. Avail online: http://www.compositesworld.com/news/premium-aerotec-boeing- demonstrate-composite-wing-technology 62. Quickstep Floating Mould: Hodgkin, J. and Rabu, N. “A New Development in High-Speed Composite Fabrication for Aerospace, Automotive, and Marine applications. 2000: Proceedings of SAMPE conference, Long Beach, CA. 63. Radius Engineering Same-Qualified RTM prototype helicopter cabin roof panel: Black, Sara. “SQRTM enables net-shape parts”. 2010: High Performance Composites. Avail. Online: http://www.compositesworld.com/articles/sqrtm-enables-net-shape-parts 64. Latecoere RTM Passenger Door: Boeing photo (Paris Air Show) . Additional Info: Gardiner, Ginger: “Cutting the cost of integrated composite aerostructures”. July 2013: High Performance Composites. Avail online: http://www.compositesworld.com/articles/cutting-the-cost-of-integrated-composite-aerostructures. 65. Light RTM Example: Zuijderduin, R. and Bottger, W. “Cobalt-free curing takes off”. 2013: Reinforced Plastics. Avail online: http://www.reinforcedplastics.com/view/30162/cobalt-free-curing-taking-off/ 66. Quickstep process illustration & photo: Luedke, B et al: Rapid Out-of-Autoclave Composite Manufacturing forAerospace-Grade Prepregs. Sampe Journal, March/April 2015, Vol. 51, No. 2. Avail online: www.sampe.org.Additional info: www.quickstep.com.au.Images courtesy of Quickstep. 177 Photo & Illustration Credits 67. Anon: “Composite Wind lades: the Boom Gets Bigger”. June 2008: Composites Technology. Avail. Online: http://www.compositesworld.com/articles/archive/863d0bd5-e4a5-42cc-a6a4-cc3583bfc0d1 68. Hinged Blade Mold: Gardiner, Ginger: HPC November 2008: “Wind Blade Manufacturing, Part I: M and P innovations optimize production”. http://www.compositesworld.com/articles/wind-blade-manufacturing- part-i-m-and-p-innovations-optimize-production. Used by permission. 69. NASAAST Wing photos: Thrash, Patrick and Ghumman, Aaron: Manufacture of Stitched Resin Film Infused Carbon Fiber Epoxy Wing Cover Panel. 1999, Vol. 52. Society for the Advancement of Material & Process Engineering (SAMPE). 70. Thermwood 5-axis router: http://www.thermwood.com/.Used by permission. 71. Robbjack cutters: MacArthur, Mike: “Tips & Tricks for Machining Composites”. . 2014: Society for the Advancement of Material & Process Engineering (SAMPE CamX Conference Proceedings). 72. OMAX waterjet): Sloan, Jeff. “Rail Car Doors: Waterjet Cutter Shapes Panels with Precision”. 2013: Composites Technology. Avail online: http://www.compositesworld.com/articles/rail-car-doors-waterjet- cutter-shapes-panels-with-precision 73. Flow Waterjet: Sloan, Jeff. “Machining Carbon Composites: Risky Business”. 2010: High Performance Composites. Avail online: http://www.compositesworld.com/articles/machining-carbon-composites-risky- business 74. Micado workholding solutions: http://www.micado.at/en/. Used by permission. 75. M Torres “TorresTool” actuated vacuum holding fixtures. http://www.mtorres.es/en/aeronautics/products/carbon-fiber/torrestool. Used by permission. 76. Water-coupled ultrasonic test: SAMPE Journal cover photo. March/April 2011, vol. no. 47, no. 2. Avail online: www.sampe.org.Photo courtesy of ATK Space Launch Systems (Utah). 77. Mil-spec tap hammer:. MIL-HDBK-337, Military Standardization Handbook, “Adhesive Bonded Aerospace Structure Repair”. Avail. Online: http://www.freestd.us/soft1/541281.htm 178 Photo & Illustration Credits

78. Boeing digital tap hammer: Boeing photo. US Patent 6748791. Commercial product under license: Wichitech RD Electronic Digital Tap Hammer. Add’l info” www.wichitech.com. 79. Quantum QFT ultrasonic flaw detector. Diederichs, Rolf. “News from the Quality Testing Show”. Seattle. Avail online: http://www.ndt.net/article/report/seattle/q_show.htm.Additional info: http://www.ndtsystems.com/ 80. Olympus Omniscan: Anon. “OmniScan MX Flaw Detector from Olympus NDT”. (Date unknown). Labcompare.Avail online: http://www.labcompare.com/24506-Ultrasonic-Flaw-Detector/2807090- OmniScan-MX-Flaw-Detector/. Add’l info: http://www.olympus-ims.com/en/omniscan-pa/ 81. Boeing ramp damage checker: Boeing photo. Commercial products under license: Olympus 35RDC Ramp Damage Checker and GE Bondtracer. 82. Bondascope 350 Bond Tester: Anon. “The Ultimate in Ultrasonics”. 2011: Quality Magazine. Avail online: http://www.qualitymag.com/articles/90020 Add’l info: http://www.ndtsystems.com/bondascope-350 83. Olympus Bondmaster bond tester: Anderson, Meindert. “Olympus NDT Introduces the BondMaster 1000e+ Composite Inspection Instrument”. 2007: NDT.net. Avail online: http://www.ndt.net/search/docs.php3?id=4820&content=1. Add’l info: http://www.olympus- ims.com/en/bondmaster1000/ 84. Imperium Acousticam Digital Acoustic Video : Boeing photo. Add’l info: http://www.imperiuminc.com/ 85. Agilent Exoscan Fourier Transform Infrared Spectroscopy (FTIR) scanner. Anon. “4100 ExoScan Series Handheld FTIR from Agilent Technologies” . 2014: LabCompare. Avail online: http://www.labcompare.com/116-Infrared-Spectrophotometer-IR-FTIR-Spectrometer/57752-4100- ExoScan-Series-Handheld-FTIR/. Additional information: http://www.agilent.com

179 Photo & Illustration Credits 86. Damaged blade: Bebon, Joseph. “GE Investigates Two More Turbine Blade Breaks”. 2014: North American Windpower. Avail online: “http://www.nawindpower.com/e107_plugins/content/content.php?content.12970” 87. Damaged windmill blades: Cohen, Tamara. “Wrecked by gales again as windfarms get £300,000 to switch off...in high winds”. 2012: Daily Mail. Avail online: http://www.dailymail.co.uk/news/article-2083149/Wind-turbines-cope-UK-weather-3- blown-pieces.html#ixzz3TQXIXeBa . A2: Wood, Karen. “Blade repair: Closing the maintenance gap”. 2011: Composites Technology. Avail online: http://www.compositesworld.com/articles/blade-repair-closing- the-maintenance-gap. 88. Blazing turbine: Ingham, John. “REVEALED: The 'hidden’ peril of wind turbines that catch fire”. 2014: London Express. Avail online: http://www.express.co.uk/news/nature/142264/Wind-turbine-fires-are-hidden-peril 89. Delaminated blade and repairs in-process: Wood, Karen. “Blade repair: Closing the maintenance gap”. 2011: Composites Technology. Avail, online: http://www.compositesworld.com/articles/blade-repair-closing-the-maintenance-gap 90. Trek Bike Fabrication: Dawson, Donna. “At the top and still climbing”. 2005: High Performance Composites, Avail online: http://www.compositesworld.com/articles/at-the-top-and-still- climbing 91. Advanced Composite Cargo Aircraft: Gardiner, Ginger. “Out-of-autoclave prepregs: Hype or revolution? “. 2011: High Performance Composites. Avail online: http://www.compositesworld.com/articles/out-of-autoclave-prepregs-hype-or-revolution 180