An Aerospace Manufacturing Perspective Introduction to Fastener Technology Part 2 1

Fasteners in Aviation Fastener Overview: – Types of Fastener: Permanent Fastening – Welding – Adhesive Bonding – Riveting Temporary Fastening – Threaded – Non-Threaded 2

Permanent Fastening Welding Adhesive Bonding Riveting 3

Welding 4 Welded Joint

Adhesive Bonding 5 Adhesive bonded composite test strips

Riveting 6 Rivet joints on a Cessna 152

Welding Fastening methods that join together two pieces of metal by melting the base metals and adding a filler material to form a pool of molten material Can be carried out by the use of heat or pressure or both and with or without added metal. 7

Types of Welding Most aerospace industry utilizes: – MIG Welding – TIG Welding – Friction Stir Welding (FSW) 8

MIG or GMAW Welding Metal Inert Gas (MIG) welding / Gas Metal Arc Welding (GMAW): – Easiest welding process – Able to bond a wide range of material types and thicknesses – Easily adapted for automation and semi-automation welding applications 9

MIG or GMAW Welding Metal Inert Gas (MIG) welding / Gas Metal Arc Welding (GMAW) Equipment: 1) Welding torch 2) Work piece 3) Power source 4) Wire feed unit 5) Electrode source 6) Shielding gas supply. 10

MIG or GMAW Welding Metal Inert Gas (MIG) welding / Gas Metal Arc Welding (GMAW) Area: 1) Direction of travel 2) Contact tube 3) Electrode 4) Shielding gas 5) Molten weld metal 6) Solidified weld metal 7) Work piece. 11

TIG or GTAW Welding Tungsten Inert Gas (TIG) welding sometimes referred by Gas Tungsten Arc Welding (GTAW) : – Most complicated welding process Requires both hands to work; one hand is used for feeding a filler metal, while the other hand is use to control the welding torch. – Like GMAW, it has the ability to bond a wide range of material types 12

TIG or GTAW Welding GTAW system setup Equipment : - A welding torch - Constant-current welding power supply - Shielding gas source 13

Friction Stir Welding (FSW) Unique solid-state welding Maintain the original metal characteristic Typically used on a large piece of metal Discovering a greater use in aerospace industry applications, such as: – Very low distortion and shrinkage – No fumes, sparks, or porosity – Repeatable – Cost and weight reduction – Improved joint quality 14

FSW process A. Two discrete metal work pieces butted together, along with the tool (with a probe). B. The progress of the tool through the joint, also showing the weld zone and the region affected by the tool shoulder. 15

Friction Stir Welding (FSW) Used to manufacture some of the Airbus component such as the wing rib 16

Welding Geometry Five basics types of weld joints are: – Butt Joint – Lap Joint – Corner Joint – Edge Joint – T-Joint 17

Adhesive Bonding Benefits of Adhesive bonding – The ability to reduce significant amount of fasteners weight in the aerospace structures – Improve the aerospace aerodynamic and performance – Able to adjust rapid temperature changes, from sub-zero temperature in the stratosphere to ground-level temperatures in desert climates 18

Adhesive Bonding Substances that are able to bond two materials together by : – Adhesion Force between adhesive and substrate – Cohesion Internal strength of adhesive itself. 19

Examples of Adhesive Bonding Internal structures with lightweight honeycomb sheets 20

Adhesive Bonding 21 Adhesive bonded composite test strips with honeycomb core

Riveting Smooth cylindrical shaft with a head on one end One of the earliest methods of fastening metal together and most popular choices in today’s applications for it is known as the most reliable fasteners Aerospace industries use hundreds of thousands of solid rivets to assemble structural parts of an aircraft Classic materials for aircraft rivets are aluminum, titanium, and nickel based alloys 22

Riveting Riveting is a primary fastening method used in aviation Much more information on riveting will follow in Aerospace Fastener Applications, Part 2, including: – Sizes and types of rivets – Rivet part number identification – Installation procedures 23