Manufacturing Plan For Wing Of PAV

Manufacturing cropes be differed according to the fabrication techniques such as sheet heightenlic element forming and machining processes. For the vanishs of a new personal childs play vehicle (PAV) clambers ands abuses be produced by sheet metal forming process and spars argon produced by machining process. at last all produced separate argon assembled together to produce concluding wing structure.In addition, since the comp integritynts that build up ailerons and flaps be actually quasi(prenominal) to wing structure, manufacturing techniques applied for skins, ribs and spars be also valid for them. Since on that point should be actuator and hinge fittings to connect ailerons and flaps to wing structure, they are considered in implementd discovers manufacturing process section.SKIN MANUFACTURINGManufacturing process of skins is shown in Figure -1Figure-1 1Tools for sheet metal forming OperationsStretching Dies, pattern fixtures, drill plates, holding toolsFirs t come forthAluminums Raw Materials are cut by shearing machine or hand r outermost to get available sizes for manufacturing with much enough excess portions. affectionateness TreatmentBlanks are then solution heat treated to tender needful mechanical properties to the part. take fire manipulation trading operations are reach according to the design take upments which are demulctd by engineering drawings. Heat treatment processes are applied to make parts primarily T4, T5 or T6 tempers.Stretch Forming SkinsOn the stretch shift, skins are stretch formed and their tooling holes are marked. After removing the skins from stretch presses, the marked tooling holes are drill for succeeding congregation operations. An example of stretch forming process is shown in Figure 2.Figure 2 2Skin RoutingRouting operation could be done with two techniquesThe first one is using a routing shell tool which has two parts which realise exactly same form of the skin. The skin is then set( p) in between them which is fixed with the tooling holes previously opened after stretching and a hand router is traveled around the tool to shape the skin to its final contour. A photo of a router shell is shown in Figure 3.The turn technique is using a five axis gantry routing center on with flexible vacuum help table. The skin is positioned with the economic aids of vacuum assisted columns as shown in Figure -4 and tooling holes are utilise to set the machining adjust axes.Figure 3 3Figure 4 4During routing operation, tack holes are also drilled. to a fault during routing operation, excess portions like access openings or some(prenominal) pockets are obliterated from the skin.Surface TreatmentSurface treatment operations are also defined by the engineering drawings. round of the line up treatment operations applied are rinsing for peeling, chromic battery-acid anodizing, primer and practical application for eroding hold onion. Primer coating and keystoneing are also called as Chemical Conversion Coating (CCC) which is beneficial for fatigue prevention.In our case, chromic acid anodizing is applied to 2024 skins for preventing eroding and paving the way for painting. Before chromic acid anodizing, fine holes should be masked to keep dimensions accurate.A typical anodise process would consist of a solvent wash and/ or an alkaline clean to draw off any oils or greases from the uprise. followed by a de-oxidiser stage to exclude the natural oxide film from the surface, followed by chromic acid. This gives you a clean oxide free surface which once anodised give give better adhesion of the anodised layer. There is a water rinse stage between each tank to prevent contamination of the bath solutions. From there you have two choices, spray presently onto te anodise honeycomb structure which will give good paint adhesion, or seal the anodised layer for enhanced corrosion protection entirely poorer paint adhesion.PaintingFinally, primer, top co at and final paint are applied on the skin. blackguard (SHEET METAL) MANUFACTURINGManufacturing process of ribs is shown in Figure 5Figure 5 1Tools for sheet metal forming OperationsHydro press forming dies, Drill fixtures, drill plates, holding toolsThe main difference of manufacturing of ribs from skins is hydro press forming process alternatively of stretch forming.Hydro press FormingAfter heat treatment, blanks become ready to be formed. In aerospace fabrication fluid cell forming (hydro press forming) is frequently apply for forming operation. That is widely distributedly because of the reality that aircraft parts are manufactured in gauzy quantities and parts are mostly unlike in geometry. Therefore it is demand to manufacture a different tool for all part and that is very costly. Although the machine is quite expensive, to decrease the tooling costs, hydro press forming is preferred since that young-begetting(prenominal) dies are necessary to form parts instead of male-female die combination. That is illustrated in the figure. Also another advantage of hydro press forming is that, on the table of the press machine, several tools, with the blanks on them, could be fixed randomly at once. In one cycle all the parts are formed simultaneously. Also in general press machines are equipped with two tables which make it possible to decrease set up time to half. Some photos cogitate with hydro press forming are shown in Figure 6.Figure 6 4SPAR, HINGE, RIB AND FITTING MANUFACTURINGManufacturing process for machined parts, spars, hinges, ribs and fittings is shown inFigure-7Figure 7 1Tools specific to machining operationsMilling fixturesMachiningIf necessary those parts which will be machined on move centers, are firstly cut from blocks of raw textile to their necessitate wrinkle sizes. They are mostly skin milled. Skin mill is done to predominate a smooth flat plane to locate the stock on the milling machine table. After skin mill, some holes are drilled on the stock for the sake of transportation and fastening on the machine tables or fixtures. For analyzable milling operations in which there are more than one stages of operations, it is common to use a milling fixture, learn Figure -8. Another reason for use of milling fixtures is that in aerospace industry manufacturing tolerances are so tight and geometries are mostly very complex that is wherefore it is necessary to provide same machining conditions and set up for every single part. Milling fixtures are tools, on which stock material is located and clamped. Their main functionality is that they hold the machined part tightly throughout the machining process which prevents machining defects and dimensional inaccuracies.,Figure 8 4To obtain required dimensional tolerances, some holes require boring. Boring operation removes only a small quantity of material therefore in front boring operation the hole must be drilled very close to the final dimension of the hole diameter.dimensional accuracy of the machined parts are generally checked with the utilization of ordain Measuring Machines (CMM). These machines are very precise such as they are capable of measuring ten thousands of a millimeter in 3 dimensional spaces. Although they are quite expensive and they need an air conditioned, humidness controlled and vibration isolated chamber, they are the most accurate and flexible beat equipments.Shot PeeningMachined parts are exposured to shot peening operation. That process is done to remove and minimize the existing surface cracks on the machined parts. Machined parts are generally bear high amount of repetitive tensial and compressive loads and these repetitive load up is mostly the main cause of fatigue failure. Surface cracks are the mostly affected defects from repeated loading and they tend to adopt under these conditions. That is why they must be removed or minimized to prevent them to grow and increase the fatigue durability of the pa rt.Surface treatmentAs explained before both chromic acid anodizing, primer coating and painting are the surface treatment operations applied on the parts to make them kind to corrosion. Another advantage of these chemical conversion coating processes is that they make the part more durable to the fatigue, since they penetrate to surface cracks, scratches and holes. For instance, pitting is a corrosion type which is more susceptible to such surface defects. Therefore surface treatment processes both provide a protective coating in corrosive environments and they generate a smoother aerodynamic surface, which is a compulsion to decrease air drag, especially for the outer surfaces which are in speck with the air during flight.ASSEMBLY OPERATIONS collection Operations are shown in Figure 9Figure 9 1Tools for assembly operationsAssembly and sub assembly dances and fixturesAssembly JigIn aerospace fabrication processes, since the parts have very complex geometries and position tole rances are so tight, it necessary to use a fixture to locate parts in their required positions and apply assembly joining operation in these positions without letting them to move. For an air plane wing a single assembly jig could be use for this purpose, see Figure 10.Figure 10 5Spars are located on the jig. They must have a planar smooth advert surface and they must have previously opened tooling holes. Those holes are used to pin the spar on the jig and some clamps are used to fix the spar in its position.Ribs are located. They are installed on the jig with the utilization contacting surface of spar and some other location surfaces and they are pinned from their tooling holes. Clamps are used to fix ribs in their location.Some of the holes are transferred from ribs to spars or the contrary.Bottom skin is loaded on the jig by the aid of tooling holes on the lugs at each lateral short edge. To wrap the rib spar assembly the skin could be pressed by some belts or some header plat es could be used to bring the skin to its required form and clamp it to hold it in its required position.Some of the tack holes on the skin are fastened with clecos, which is a fly-by-night fastener. Pilot holes are drilled to their final sizes and countersinking is applied to locations where countersunk rivets and bolts will be used.After drilling and countersinking is applied parts are separated to remove chips.Before putting parts together again, sealant is applied. Sealant is a viscous chemical isolation material which is a polymer in general (polyurethane, polysulfide, etc). It is applied when it is still in fluid form and it solidifies as a result of chemical reaction which takes place as soon as the sealant is exposed to air. They are used to prevent fluid escape into internal structural components. This leakage could result catastrophic failure since corrosion which erodes material would work against the mechanical strength and stiffness of the structure. For different pur poses and for different locations specific types of sealants are applied. For instance polysulfide based sealant is applied to the surfaces where there is fuel content. For fuel tanks these polysulfide based sealants are used since they withstand the fill out of sulfur compounds that are present in fuel.After sealant application, outer skin is brought to close the wing and it is fastened with blind rivets and bolts since it will only be possible to reach rivet from one side.When riveting and bolting finish the wing is removed from the assembly jig and it is sent to paint bewray for the application of top coating and painting. After that manufacturing and assembly operations will be completed.