Aircraft Parts Fabricating Processes PDF

ME2511 Aircraft Structures Aircraft Parts Fabricating Processes Parts Manufacturing Processes  Manufacturing Processes Formed Section Metal...

ME2511 Aircraft Structures Aircraft Parts Fabricating Processes Parts Manufacturing Processes  Manufacturing Processes Formed Section Metal Spinning Sheets Understand each manufacturing Objectives Stamping process and Extruded Learning Section its application Casting Forging  Manufacturing Processes Fabricated Aircraft Element and Joining methods Aircraft sub-assemblies and components are fabricated from stock material of sheet, formed section, extruded section, forging or casting joined together by various fastening methods.  Manufacturing Processes Sheets Billets or slabs of metals are heated to above critical point and rolled into sheets, bars or channels of uniform cross section. Where accuracy of dimensions is desired, the stock is further rolled in cold condition known as “Cold Rolled” stock. Special areas like wing root end skin are cold rolled to tapered cross sections; and sometimes with raised stiffeners during rolling called “Integral Stiffeners.”  Manufacturing Processes Extruded Sections Some material like high strength aluminium alloys, are extruded, while in a hot plastic stage, under pressure in dies to give uniform cross sections of T, I, U, V, L or different shapes to be used as reinforcing stiffeners and stringers. Some high strength alloy extruded sections are used as chord members for ribs, root ribs and spar of wings or as fuselage bulkheads. Aluminium Extrusion Press.flv  Manufacturing Processes Forgings Some aircraft structural members are odd shaped and of varying thicknesses at different sections. This problem is solved by forging the member while the metal is still in the hot and plastic state using power hammers, hydraulic or heavy presses. The grain flow adds to the strength of the material. Highly stressed part like the landing gear are made of forged high strength steel while wheel hubs, window frames, etc. are made of forged aluminium alloy. Basic Metal Working Techniques.flv  Manufacturing Processes Formed Sections Sheet material is often re-rolled to form constant “Z”, Hat or “S” sections to be used as skin stiffening stringers. They may later be further bent and formed into circular shapes to make leading edge for wings, formers for the fuselage, etc. Sheet Metal Shearing & Bending.flv SHEETMETAL FORMING.flv  Manufacturing Processes Stamping Large number of parts are identical shape, like wing ribs with uniform thickness and are quite often stamped from sheets using male and female dies. metal stamping.flv  Manufacturing Processes Casting Components having very intricate shapes like cooling fins of engine cylinders, or light components of odd shapes are often cast using liquefied metal poured into moulds. Sand castings, die-castings, are some methods used, depending on the accuracy of finish and strength required. Small brackets, control quadrants, lightly stressed fittings are usually made by this process.  Manufacturing Processes Spinning Thin sheets shaped with a blunt tool, while rotating are used occasionally for specially shaped components like propellers spinners, hub caps etc. metal spinning.flv  Joining Methods Aircraft structural elements are joined to one another by various methods/processes subject to their respective maintenance requirements. Aircraft fasteners (sample) Joining Methods Highly stressed joints such as wing spars to wing skin, wing to fuselage, etc. are fastened with steel fasteners having aluminium alloy collars swaged to them  Joining Methods Fuel tank areas, where prevention of leakage is critical, lock-bolts of close tolerance drive and not hi-shear type are used.  Joining Methods Welding is usually confined only to steel components like landing gear parts. Aluminium alloys are not welded because of poor strength and structural changes in the metals Spot welding may be adopted if necessary.  Joining Methods - Rivets While using rivets, only solid rivets are acceptable except in inaccessible places where the manufacturer may use blind or tubular rivets.  Joining Methods Assemblies or sub-assemblies, that need not be disassembled in service, are usually fastened by permanent fasteners like rivets, lock-bolts, hi-shear rivets.  Joining Methods A method of driving aluminium alloy rivets named “NACA riveting” is used in fuel tank areas as this method assures lead-proof self sealing joint.