Along the bond line Groundbreaking structures Metal bonding

Thousands of years ago man became aware that some substances are really sticky and can be used to fix and assemble parts. This discovery developed into knowledge and art of gluing or bonding, a very useful engineering and manufacturing skill to attach similar or different materials to each other.

It is quite obvious to use an adhesive substance from a tin could actually substance made from plants or provide structure to this magical new animals to connect wood to metal of the future. something else. Nevertheless in the The concept of bonding metal to 1930’s something weird and metal was invented in the UK, in the untraditional happened: the age when science and engineering discovery that you could actually bloomed. From then on recipes bond two pieces of metal together gradually improved and became more with some kind of seemingly inferior refined and precise. was an polymer and that this connection was early adopter and has over 50 years strong beyond expectation. It went of experience with manufacturing even further. This primeval principle adhesively bonded aircraft structures. facilitated bonding of the epitome of Some of the early Fokker F27 progress, the very symbol of passenger aircraft, featuring wings Modernity: . with bonded wing structures are still Counterintuitive is the word here. It is in service. Metal bonding has proven only logical that many engineers to be a very reliable and flexible simply didn’t believe that a treacly technique for metal part assembly. The thin-walled nature of metal Sample to demonstrate structures turns bonding into an bonding potential excellent construction method, even to the extent to which bonding more thin layers of aluminium with multiple bond lines is an attractive concept to gain quality and save weight, when compared to just metal. Metal bonding is trustworthy far beyond reasonable doubt and it is destined to develop further. Gradually new advantages of metal bonding, concerning design, production, operation, damage resistance and tolerance, have indeed been discovered. The first is bond strength itself. A bonded lap shear joint between two metal sheets can be configured in such a way that, against all odds, over-stressing will cause the metal adherents to fail, and Gulfstream G650 bonded panel not the adhesive. An even more on aluminium sheets bonded convincing feature emerges when a together with glass-reinforced epoxy stack of thin adhered metal sheet is layer is used as skin material for a used in a structure instead of a large part of the A380 fuselage. As a single thick plate. Adhesive layers consequence the Glare part of the act as effective crack stoppers. They A380 fuselage is certified to do not allow cracks to grow all the need no inspection at all in 20,000 way through the stack, thereby flights. If you want offering a very effective way of resistance bonding is the way to go. designing damage tolerant skin. Metal Bonding and Metal Fibre Similarly damage tolerance is much Laminates are an important building better served by building up plate block for future aircraft. thickness with adhesively bonded doublers than by etching or milling thick plates. Fibre reinforcement of adhesive layers enhances damage tolerance of bonded stack of sheets even further. When cracks occur in the metal sheet, the fibres will contain the crack opening and considerably reduce crack growth rate. Fokker applies this principle in its ‘Fibre The major part of the Metal Laminates’ Key Technology. fuselage consists of Glare panels, Glare, a fibre metal laminate based which require no inspection future

The development of airplane manufacturing is an evolution of beliefs, fed by a steady increase in factual knowledge. The first airplanes were made pragmatically, merely to make them function, from materials that were easy to work and readily at hand: wood, rope, linen, a few steel bits. Then times got modern and with that the belief in the potential of metals grew quickly. Before long riveted aluminium became the technology to put your money on. It gained the bias of belief. Because of this from the 1940s onwards almost every airplane is designed as a riveted aluminium structural concept.

The birth of metal bonding happened materials, manufacturing and almost simultaneously with the architecture for each part and for upcoming belief in metal structures, every assembly, all to best serve the but was not readily accepted, for lack customer. Metal bonded structures of trust. It took a while, but now we are a strong option. clearly have arrived in an episode of Fibre metal laminates are a good recognition of the full potential of example of creating such a balanced combining different materials in solution, in which the engineer is structural design. Increasing neither forced to resort to one type of knowledge and experience in material, nor to a particular aluminium and composites: that is composite. Engineers can be perfect what inspires Fokker. No single tailors. Their domain is where material is perfect in every sense. structure and material merge and Finding the right balance is what where material therefore becomes matters. The ultimate solution is not subject to design and engineering one particular substance, but rather a rather than to choice. way of thinking. Every design In this way changing context and question has a different context and continuously increasing knowledge requires to be answered with an determine the outcome of design Cross section of future BWB ‘Clean Era’ optimised set of properties that solutions. It implies that all options (TU Delft, Zeger van der Voet and belong to a combination of certain must be kept open, sometimes until François Geuskens) materials. The proper approach is to the last minute. Timing and planning select the best combination of can determine decision outcomes. Monolithic aluminium, or carbon fibres with epoxy resin, or aluminium adhesively bonded to titanium? Thermoplastic PPS? Bioplastics? There is no fixed answer. That is the essence of innovation.

Laser projection indicating the boundary of the bond film to be applied on aluminium and glass film during lay-up

Adhesive past

Norman de Bruyne, an English physicist with a British mother and a Dutch father, invented metal bonding and created the first man made adhesives. The idea to develop glue for metals did not appear out of the blue. An idea needs food for thought to ripen and subsequently reveal itself as a new opportunity. One thing is needed before it can lead to another.

De Bruyne founded Aero Research balsa wood. It was named . The Ltd to develop new solutions for word sounds chemical, but it simply is airplanes. He created a wood an abbreviation of REsearch at adhesive in which the chief engineer DUXford. To this day the brand name of got quite interested. is in use, also for modern epoxy Together they experimented with a adhesives. The company later sandwich structure that involved a introduced the first film adhesive. In balsa core. This became one of the 1939 De Bruyne presented Gordon structural principles in the Mosquito Aerolite, a laminate of flax roving a very successful fighter aircraft and and paper soaked with phenolic in fact an early ‘composite’ aircraft. resin. Interestingly he originally Its basic airframe structure consisted wanted to use a fine fabric woven of wooden elements glued together. from glass fibres instead of flax, but Then a new phenolic adhesive was the American glass producer didn’t developed to bond aluminium to want to cooperate: he expected structural failure. Failure in played an important role in the judgement is what he got. Glass wing and fuselage structure, but fibre reinforcement is everywhere design flaws in the overall detail now. After the war Aero Research design of the aircraft unfortunately became quite successful, producing overshadowed the excellent vast quantities of adhesive for wood performance of the bonded joints, laminate production. The Swiss slowing down the proliferation of chemical giant CIBA bought the the metal bonding technology. As company. far as bonding connections were The first aircraft producers to take concerned: they remained intact for up use of adhesives for carrying years on end and contributed to the structures were English. De legendary durability status of Redux Striking similarity between De Havilland daringly developed the 775 adhesive. Havilland Mosquito production in Comet, the first passenger jet with a wood, in the1940’s, and current panel pressurised fuselage. Adhesives assembly at Fokker Aerostructures Early adopter

Rob Schliekelmann, one of the visionaries of Fokker, adopted bonding. It became one of the Key Technologies of the company. He recognised the main advantages of more efficient production, improved fatigue resistance and better distribution of forces from the very beginning. His true understanding of the technique’s nature readily led Fokker customers to accept adhesive bonding.

The extensive use of bonding made which basic skin, doublers and the (1955) and stiffeners are assembled by adhesive its upgrade the very bonding have become a Fokker respected successors of aircraft like product-technology combination that the DC-3 ‘Dakota’. They were a huge Fokker marketed successfully as a tier economic success. This workhorse is one supplier to many of its customers still being operated in various regions ever since. of the world, often under harsh The Fokker adhesive bonding conditions, which is excellent technology has been and still is evidence of the concept’s durability continuously improving in every and reliability. Obviously adhesive respect to meet higher demands on bonding was applied in the Fokker jet technical and economic performance. aircraft as well, starting with the F-28 The initial application of phenolic Fellowship in 1967 and its successors adhesive as a two-component system the and twin was cumbersome. From the early jets. The wing and fuselage panels in 1960s onward film started to replace

Early Fokker F27 ‘Friendship’ the jars and cans of treacly glue and curing temperature, as well as powder and the process became strength, brittleness, ductility and much better controllable. heat resistance can be tailored to Phenolics are thermosetting resins many different applications. When that cure through a condensation the curing process is proceeding, reaction, producing water that needs epoxy resins have a very low viscosity, a way out during processing. This which is an advantage when far implies a limitation to surface sizes away surfaces are difficult to reach. that can be bonded. Although Epoxy adhesives with low viscosity phenolic systems do show are supported by a polyamide scrim: endurance, epoxy resins allow tuning a curing reinforcement that also to a wider range of different contributes to structural quality. In requirements. In structural bonding interior applications phenolic epoxy resins currently have the edge systems prevail because of their over phenolics. Properties such as better fire resistance.

F27 fuselage and wings belonged to the first bonded aluminium aircraft structures Nano grip

It is a well-established fact that bonded aluminium structures can be trusted to function for years on end. From early on it was clear that adhesives do a good job. Thanks to the development of measuring instruments it is only now that it gradually becomes clear how the bonding system works. Intuition and empirical evidence are replaced by knowledge.

Aluminium that is going to be bonded (Scanning Electron Microscopy) gets a thorough pre-treatment. The reached a sufficient level of surface has to be prepared for an magnification and resolution to reveal adhesive to attach itself to. First a in detail what actually happens solvent degreases it, next the surface during anodisation. Apart from what is pickled to remove the ‘old’ natural the images tell us about the process, oxide layer and subsequently they are simply stunning. They show a anodised to form a well controlled structure with definite honeycomb oxide layer. The procedure is familiar, characteristics. In some instances but when anodisation, an pores are on the tops of tiny ‘tree electrochemical process in an acid, trunks’ in a nanoscale ‘rainforest’. was first executed in 1923, the main, And their density is phenomenal. vaguely defined, purpose was to Adhesive can find its way into tens of protect aluminium against corrosion millions of pores per square by building up a thin layer of millimetre and firmly attach itself. It is aluminium oxide, or alumina as it is a level of precision that rivets will commonly known. Over the years it never ever reach. became an familiar technology and The effect of process parameters is requirements for process parameters much more clear now. The layer got clear through research. grows upward from the barrier, the Production parameters were basically boundary between aluminium and clear. Nevertheless researchers had to alumina. Voltage defines pore size: make assumptions on oxide density, the higher it is the wider the pores. constitution of the layer, and the size This implies that pores on top of the and shape of pores. oxide layer have a slightly smaller It was not until recently that SEM diameter because the current takes

SEM images of anodised structure analysed by computer (right) to determine nano-scale definition of cavities. some time to get to its maximum. layer. The average pore diameter SEM image, obliquely from above, Another characteristic is that the tends to be around 20 nanometres in showing structure of anodised concentration of aluminium in the a normal anodising process. Metal alumina layer determines the definition of bonding appears to be large scale the structure. Clad aluminium, for nanotechnology. Until recently no instance, is likely to produce a one was aware of that. smooth structure with columnar pores, whereas bare aluminium with relatively low aluminium content will result in an irregular spongy alumina Force distribution

Rivet connection (left) only attaches holes. load will cause detachment. Bonding (right) provides true surface connection.

To understand the principle of bond another effect will make itself known: function: take two times two similar a riveted structure will start buckling plates of aluminium. Bond one pair at a lower load, again because the together, with an overlap, and rivet parts are not really attached to each the other, with the same overlap other. There is ample opportunity for proportion. Now load the two them to deform from underneath the contraptions, which are identical heads of the rivets. Again bonding is except for the attachment, with a the winner. tension force each. Adhesive will An old argument against aluminium spread this disruptive power over the bonding is that adhesives are not as interface between two bonded parts, strong as the metal. That may be true, thus reducing its effect. When but this is not the point. Adhesives compared to riveting levels are reduce the stress to a level that they much lower, for the two layers held can easily survive under standard together by rivets are simply not conditions. It is always better to test bonded. They rather act like scissors and compare integrated solutions that try to cut rivets in two. All forces rather than to make judgements pile up at the edges of the holes that based on analysis of material contact the rivets. As a result the properties of separate ingredients. bonded structure is stronger. Replace tension by compression and Stop crack growth

Fatigue is aluminium’s main weakness. The load doesn’t have to be near the level of material strength, but when it is varying with a sufficient rate, after a certain time tiny cracks will start to appear. Next they will slowly grow and diminish the amount of stress the metal can handle, until on some fatal moment there is not enough connection left over to deal with even a moderate force. The metal will break.

The advantage of bonding, apart careful engineering. For one thing from being a convenient way to the thickness of bonding layers connect parts, is that an adhesive will doesn’t join the scale game: one can stop fatigue cracks from growing. choose to increase the thickness of They will still pop up and maybe aluminium, but adhesives have start to propagate a tiny bit, but rather fixed thickness requirements. they are not able to cross the Looking at bonding from yet adhesive ‘swamp’. The relatively soft another angle it is a method to polymer almost literally removes the produce large skin parts in which edge of a crack and thereby reduces the adhesive contains layers of stress. unidirectional glass fibres. Now we Because of this phenomenon it can are talking fibre metal laminates, or be smart to not just bond parts, such Glare. Fibres provide even better as stringers and skin, together, but protection against crack growth, also to compose thicker attachment because they remain intact when elements of bonded layers of the crack is moving past and prevent aluminium. Building up a structural it from getting wider. Glass fibres element like this resembles 3D act as a stubborn distributor of printing, in the sense that a part is forces across crack flanks. This made through addition, stacking up so-called ‘bridge-effect’ reduces the layers, rather than milling away stress in the crack hotspot, the place what is not needed. where all this awful tearing apart The translation of a one material happens. Glass puts a true break on part into a layered structure requires crack growth.

A fatigue crack is a knife edge turned inside out. Adhesive (left) renders the edge too blunt to reach the next aluminium layer. Glass fibres (right) are strong enough to bridge the gap (‘bridging effect’) BASSA

THE CONVENTIONAL Other options in bonding have made METHOD OF THE BASSA ASSEMBLY SOLUTION their entrance as well. It is obvious that bonding without the need of subparts subparts (standing with (standing with using an autoclave is interesting. As positioning positioning experience with this type of attaching holes) holes) parts together is increasing, other advantages have revealed themselves. Pre-drill in jig Load parts subparts time Assembly with the help of an adhesive in jig and apply can render a lot of drilling and in jig adhesive riveting preparation work superfluous. Load parts, time in jig This technology, BASSA, short for Cure Bond Assisted Single Step Assembly is adhesive at Drill part of room a combination of bonding and the holes to temperature shimming with a thixotropic cold or final size hot curing adhesive. The bonding agent can fully compensate small Drilling and Lock holes riveting (less Part held structural imprecision. BASSA requires using clamps rivets) on Pick extensive tooling, but labour costs are up points relatively low. Fokker Aerostructures Drill rest of applies this promising technology to holes to final size connect the complete upper and lower skin of a control surface or an entire tail to the inner substructure of Remove parts in jig spars and ribs. BASSA, this highest and deburr level of bonding to create full assemblies, is in use for Gulfstream in jig Load parts in time . In primary joints adhesive jig and apply sealant bonding can be combined with blind riveting, to achieve ultimate strength. Rivets alone would limit maximum Control shim thickness load. BASSA is another important during building block for future aircraft. drying

Rivet the assembly

Complete tail section bonded in one go with cold curing adhesive, in a labour saving elaborate mould

Bonds and Laminates

For bonding aluminium Fokker Aerostructures operates two kinds of production lines. One is strictly for adhesive assembly and the other involves glass fibre. These are part of unidirectional reinforced adhesive film, which serves to produce Glare metal fibre laminate parts. The presence of glass is the crucial difference.

Aluminium fuselage doublers milled and in stock for bounding Black bags containing prepared Metal bonded parts are cut into Glare parts are usually much larger rolled aluminium sheets for Glare shape, stretched and tempered, to than bonded parts, much larger in lay-up tune their crystal proportions and fact than standard aluminium plate arrangement. It is basically the same sizes permit. After all Glare is about as traditional production of assembling very large skin parts in aluminium parts for riveting. the range of 30 sq. metres, including The required thickness may vary and stiffeners. The raw material is very saving weight is a matter of leaving thin (0.2 - 0.5 mm) rolled sheet. The out sheet where it is not needed. preparation for further production Moreover, because of this layering consists of unrolling, cutting, principle combining different alloys pretreating, and consequently rolling is simple. The outside skin can for up the skin elements again, instance be an Al2024 alloy, which is protected by a layer of paper. A less sensitive to fatigue, whereas the typical Airbus A380 panel is built inner layer could be a stronger, but from 22 of these elements. slightly more corrosive Al7075 plate. Smooth assembly

The principle of assembling parts prior to bonding is quite simple: just stack elements and layers on top of each other, with the proper pieces of adhesive film between them. In practice the difficulty is in acquiring the right level of precision in a sufficiently clean environment. Parts to be bonded are placed in jigs, mostly by hand, and different layers get positioned correctly with the help of pins. Large relatively flat surfaces are layered with support of lasers that project the right shapes and positions on the material in green light. Here is an unexpected reminiscence of procedures in the graphic industry. During lay-up the adhesive is just a film, from which protective foil has to be removed. Obviously the trade-off between hand lay-up and automation depends on production volume. It is likely that in the near future robots will gradually take over this kind of work.

Aluminium sheet being rolled out over a layer of unidirectional glass reinforced adhesive film

Layering

The position of conscutive layers is defined with laser projection After positioning all these neatly inclined to overlook, but when clients, prepared parts are placed into occasionally celebrities, come to have the autoclave to be united by heat a look at the making of their newly and pressure. purchased plane, they tend to feel When they come out the result looks comfortable with slick looking aircraft smooth. It is an advantage one is parts in a quiet environment.

Large autoclave for curing completely assembled A380 Glare panels

Greenification

Saving weight and cost are the main forces behind innovation in the aerostructures industry. These parameters are rooted in environmental effects. It is a domain where the relationship between economy and ecology is transparent. That may be the reason why air travel is quite efficient when compared to other forms of transportation

Production systems for aircraft ever. We have passed the stage of structures still have a lot to gain in ‘see if it works’ and have arrived in a the field of environmental effect. For situation where we can establish if one thing it requires a considerable the oxide structure looks just right amount of energy. Chemical pre- through a powerful microscope. Anodisation facility overview treatment is currently getting Bonded structures have many attention because of the substances advantages in production, involved. The number of chemicals functionality and keeping the weight we like to ban from our industry is and aircraft fuel burn low, but taking growing. Particularly chromic acid, them apart and recycling them is still which is used to pickle and a hard nut to crack. The basic consequently anodise the metal, is alternatives are of course to do it due to disappear and be replaced. mechanically, thermally or chemically Fokker Aerostructures is currently - they are being studied, but because developing a new line of pre- of the high structural quality one treatment. The successor is likely to could also argue to try and reuse be a very similar method with airplane sections for different different chemicals, but other options purposes. After all, compared to have announced themselves and other industries the total production could find their way to the mass of airplanes is not very large. world. In the automotive industry Seen from the viewpoint of surface treatment is getting physical innovation, it is clear that current through the use of plasma. This type structural solutions are not final. of development is quite interesting Some fibre-reinforced bridges now since the desired effect of whichever consist of renewable polymers. treatment it will be in the future, Something similar could happen in now is more thoroughly known than aircraft production.

technology on site recovery production of product change and reuse useful by-product modfication

Cleaner Production

good input material better process equipment housekeeping change control modification Glorious Glare

Over 30 sq. metres of finished Glare for the Airbus A380, including stringers

Fibres to enhance the quality of in 1981. ARALL, however, required repair do not really differ from that aluminium have been under extra handling during production, to of aluminium. Since the aluminium consideration for quite a while. The deal with residual stress. and glass reinforced epoxy layers original idea was to bond aluminium Switching to glass fibres solved this form themselves in the mould, the with aramid fibres. They became the issue and created the baseline for differences in formability of metal main ingredient for a new composite Glare, which got patented six years and composites are easily handled. Al named ARALL, short for ARamid later. For a fuselage structure, fatigue these benefits come with an extra Aluminium Laminate. It got patented resistance against loading in two plus: Glare’s density is about 10 directions is required. It is possible to percent lower than that of combine unidirectional reinforced aluminium. The actual density can GLARE VS. ALUMINIUM COMPARISON RATIO adhesive layers that are positioned in vary, depending on lay-up design. All Weight different directions. Fibre metal in all it was just a matter of time for – density 0.85 - 0.90 – structural 0.70 - 0.85 laminates with these bi-directional an airplane company to start applying reinforcements are ideal to withstand fibre metal laminates. Airbus’ decision Strength 1.0 - 2.0 the forces in fuselage skin. in 2001 to use it for the A380 fuselage Fatigue 3.0 - 100.0 Implementation of such a new meant Glare’s crucial breakthrough. structural principle takes years. As a true hybrid its functional Damage tolerance 1.0 - 2.0 Intensive testing did demonstrate advantages are less radical than those resistance 1.0 - 2.0 that Glare features good impact and of fibre reinforced polymers. In many Flame resistance 5.0 - 50.0 corrosion resistance. Since it is aspects Glare can simply be treated as aluminium it can deal with lightning a kind of aluminium. Nevertheless Lightning strike 1.5 - 2.5 strikes and because of the glass fibres Glare is lighter and much more Thermal insulation 100.0 -150.0 it is quite good at containing flames reliable than aluminium on the long Corrosion resistance 1.2 - 3.0 in case of fire. The composite ina run. Its impact resistance, particularly between aluminium blocks corrosion against bird strike is proving its Repairability better as well. A very important advantage value in the entire front end of the Maitenance better is that its production assembly and A380 tail. Increasing knowledge

Taking part in a large primary Yet designing the directionality of the structure is the highest ranking fibres in a certain way determine its achievement for a laminate. If it can mechanical properties. This is where do that it can do virtually anything. the two faces of the Glare-hybrid turn Because of its high impact resistance interesting. Originally fibres were Glare can be applied in leading edges included to enhance fatigue resistance that may suffer from bird strike or in aluminium, but aluminium also other kinds of impact. The A380 tail works to the advantage of the glass leading edges consist of Glare. fibre reinforced adhesive it encloses. There may be interesting potential in Two layers of glass fibre film with the fact that Glare is a glass different directions together form a reinforced adhesive polymer covered very thin composite, but the sum of by a metal, which naturally conducts fibre directions still results in electricity. An integrated de-icing anisotropy when it comes to force application is currently being distribution. Here aluminium functions developed and there may be more as a stress equaliser. When considered fancy opportunities, such as boundary in this way, in certain situations fibre layer control through static electricity. metal laminate can result in a thinner Investigations on Glare so far show, structure, which saves weight when that the hybrid generally performs compared to a pure polymer better than metal without glass fibres. composite. You could define Glare Its compatibility with aluminium also as an ultra thin aluminium implies that principles for design and reinforced polymer glass composite. production development are familiar.

Limitations

In theory it is not impossible to bond an entire airframe in one go, to avoid all bolts and rivets. It would not be easy though, or cheap. This extreme example does bring forward the two main limitations of the use of hot curing adhesives: complexity and size.

The more parts and layers have to be bonded together in one go in the autoclave, the more complicated the curing preparation will be. A complete tail section, for instance, would require a huge, heavy and very Induction welded edge expensive jig, which will have to with clean seams. include hinging or detachable pieces with clamps and bolts and things. And the more complicated tooling is, the optimise the balance of investments more vulnerable. Moreover the and process. autoclave will have to be sufficiently Fokker Aerostructures designed spacious inside. Once taken from the Glare fuselage skin plates for Airbus jig after curing you would have this A380 for road transportation, with inert big structure that would need such a size that they fit upright transportation. Inside a plant this is inside a container on a low loading not uncommon, but to move it trailer. This vehicle takes the elsewhere, to another country for containers to a nearby harbour. Here further assembly, could lead to over ships take over and bring them to stretching the system. Currently it North where Airbus already is at its limits. Careful assembles fuselage sections to be production design is needed to transported to the south of for final assembly. Glare design

Since Glare is a composite, it entails a provided by aluminium suppliers can lot of freedom for designers to be overcome by creating overlapping integrate the right properties for structures, so-called splices, in their required functionality for varying cross-section comparable to load conditions all into one brickwork. These overlaps need to be advanced structure. Overall quite precise, in particular along thickness, number of layers, alloy edges where the skin panel needs to composition, number and be attached to thmain structure directionality of glass film layers, through rivets or bolts. For no matter they can all vary within the design of how advanced the possibility to Glare panel edge clearly showing one skin panel. With the help of fine-tune Glare properties to doublers and splices software structural efficiency can function is, classic mechanical be optimised. engineering remains part of the deal. Because of layering integration opportunities are abundant. One can for instance integrate stiffening layers between the aluminium plates. The limitation of sheet width Inside Glare

GLARE© DESIGN FEATURES – “GIANT” TOOL BOX

Splice in skin panel or doubler

Limitation of aluminum sheet widht Internal stress level in double curved panels

Additional layers

Embedded at frame locations

Inter-laminar doublers

Spliced or go thru depending on lenght and orientation

Ultrasonic scanning robot operating with sound wave guiding water jet, to detect Fiber Orientation Lay-up faulty production details

When a Glare panel is ready, fresh aluminium layers, or unwanted pieces from the autoclave, it needs to be of protection material. Adjust properties to loading condition thoroughly checked, for it is a Ironically such an advanced inspection complicated hand-made structure. For system is not necessary when Glare is Transition of GLARE© type that purpose Fokker Aerostructures damaged through impact. The dent is

employs an ultrasonic scanning a good indicator for the shape and system. Every skin panel is checked the size of delamination. It always

entirely, millimetre by millimetre, to stays inside the borderline of e.g from GLARE© to GLARE© 3 see if there are no suspicious looking aluminium deformation. The repair

Additional layers loose fibre ends between the procedure is traditional.

Aluminum sheet locally at frame station Glass fiber layers locally between two aluminum sheets

Scanned image showing area with air enclosure

Continuous innovation Fokker operates at the forefront of aircraft innovation. This is a crucial strategy for a supplier in global aircraft industry. In the continuous process of functional improvement, weight and cost reduction, and the evolution towards sustainable air transport, lagging behind is no option. For metal bonding and the development of metal fibre laminates this implies continuous improvement and looking for the most intelligent combinations of material properties, from the nanometre scale to large aircraft sections. Continuously increasing insight and adaptation to changing circumstances will keep on improving structural quality. In a system of technology roadmaps, from the current state to the future, Fokker Aerostructures, proposes new concepts, selects the promising ones and develops the best into feasible product technology combinations. In the avant-garde of innovative sustainable development Fokker participates in networks of universi- ties, customers, co-developers and suppliers in which skills and knowl- edge are shared and improved. Exploring the newest is both neces- sary and, admittedly, quite exciting.

Fokker Technologies: Fokker Aerostructures Inc. Industrieweg 4 12121 Harbour Reach Drive, Suite 205 FOKKER TECHNOLOGIES PO Box 1 Mukilteo, WA 98275 USA 3350 AA Papendrecht Tel USA: +1 206 304 3489 STRUCTURES & ELECTRICAL SERVICES The Tel NL: +31 6 1332 1658 LANDING GEARS SYSTEMS Tel.: +31 78 641 99 11 Fax: +1 253-395-2658 Fokker Fokker Elmo Fokker Fax: +31 78 641 96 00 Email: [email protected] Aerostructures Services Web: www.fokker.com Fokker