An Aerospace Manufacturing Perspective

1. Aerospace Fastener Applications Part 2 An Aerospace Manufacturing Perspective

2. Aerospace Rivets • Primarily used to fasten aerospace skins to the sub-structure • Concerned mainly with shear and tension loads. • Two types of rivets: • Solid Rivet • Blind Rivet

3. Aerospace Rivets • Rivets on the skin of a Boeing 737

4. Aerospace Solid Rivets

5. Aerospace Solid Rivets • Universal solid rivets on the skin of a Boeing 737 • Note that they are not flush with the skin

6. Aerospace Solid Rivets • Countersunk solid rivets on the engine pylon of a Boeing 737 • Note that these rivets are flush with the surface

7. Aerospace Solid Rivets

8. Aerospace Solid Rivets - Identification • Rivets manufactured in accordance with the AN/MS standards are identified by a four part code: • AN or MS specification and head type • one or two letters that indicate the material • shank diameter in 1/32nd inch increments • a dash followed by a number that indicates rivet length in 1/16th inch increments.

9. Aerospace Solid Rivets - Identification • Aircraft rivets are made of many materials, and come in a wide variety of shapes and sizes • How do you select the right size? • How do you select the right material? • We must know what the part number tells us…

10. Aerospace Solid Rivets - Identification • Example: rivet identification • standard universal head solid rivet • Material: 2117-T4 aluminium • 1/8 inch diameter • 5/16 inch in length • Rivet ID = either AN470AD4-5 or MS20470AD4-5

11. Aerospace Solid Rivets - Identification • Same rivet, different material:1100 aluminium • AN470A4-5 or MS20470A4-5. • AN470 or MS20470 denote the specification for universal head types • AD is the material code for 2117-T4 • (A=1100, B=5056, C=copper, D=2017, DD=2024, F=stainless and M=Monel) • 4 = 4/32 or 1/8 inch diameter • -5 = 5/16 inch length

12. Aerospace Solid Rivet Installation • Rivet installation summary • Drill appropriately sized holes • Deburr holes • Secure pieces together with Clecos • Install rivet, buck with rivet gun or use a rivet squeezer

13. Aerospace Solid Rivet Installation • .032” 2024-T6 sheet aluminum to be joined with rivets • Rivet gun • Bucking bar • Drill • Drill bit and chuck key • Center punch • Cleco • Cleco pliers

14. Aerospace Solid Rivet Installation • Drilling holes with a #30 drill bit • Use 1/8” rivets with a #30 (.1285”) drill bit

15. Aerospace Solid Rivet Installation • Deburr the holes by rotating (by hand) a much larger drill bit in the holes • This removes any metal shavings caused by drilling

16. Aerospace Solid Rivet Installation • Position the pieces together and secure using Clecos • Clecos maintain proper alignment of the pieces while rivets are being installed

17. Aerospace Solid Rivet Installation • Place the rivet in the hole • Make sure you are using the correct size, material, and type of rivet

18. Aerospace Solid Rivet Installation • Align the rivet gun on the rivet head • Hold the bucking bar on the opposite end of the rivet • Pull the trigger on the rivet gun to hammer the rivet in place

19. Aerospace Solid Rivet Installation • Solid rivets can be installed using a rivet squeezer instead of a pneumatic rivet gun • The squeezer is hand operated • The squeezer uses various inserts depending on the type and size of rivet being installed

20. Aerospace Blind Rivets • Used when you cannot physically access one side of the work • Blind rivets are hollow, and thus weaker than solid rivets • To retain strength of the joint: • stronger material, larger diameter rivets, or more are necessary and of course • 20–50% heavier than a solid rivet because of steel stem

21. Aerospace Blind Rivets

22. Aerospace Rivets – Fuselage Repair • Exterior of a riveted patch fuselage skin patch • Note that solid fasteners are used except in the middle of the patch • Why would you use blind fasteners in this application?

23. Aerospace Rivets – Fuselage Repair • Interior of a riveted fuselage skin patch • Because the stringer on the interior of the fuselage prevents the bucking a solid rivet requires • Blind rivets are the only option when access is restricted

24. Quality Assurance of Aerospace Fasteners • Aerospace Fasteners Material Selection • Aerospace Fasteners Testing

25. Aerospace Fasteners Material Selection Background • Some factors to be considered before material selection are: • The max. and min. operating temperatures • The corrosiveness of the environment • Fatigue and impact loading • Always try to use standard fasteners, such as AN, MS, MIL, NAS, SAE

26. Aerospace Fasteners Material Selection • Alloy Steels • Aluminum • Titanium • Stainless Steel • Superalloys

27. Aerospace Fasteners Material Selection • Aluminum is the predominant material used in the manufacture of commercial aircraft. • Table 3 lists the typical aluminum alloys used in commercial aircraft.

28. Basic Aerospace Fasteners Application • The basic applications (or needs) for aerospace fasteners are: • Shear • Tension • Fatigue • Fuel tightness • High temperature • Corrosion control

29. Aerospace Fasteners Testing • Analyzing a Joint • Calculate all the load required for each type of joint failure: • Rivet Shear • Sheet Tensile • Bearing • Sheet Shear • Failure will occur in the mode that corresponds with the lowest load carrying capability.

30. Aerospace Fastener Standardization • Most aerospace hardware is manufactured per government standards • The three most common aircraft fastener standards used are: • AN = Air Force/Navy • NAS = National Aerospace Standards • MS = Military Standards

31. Common Standardized Fasteners • Bolts • Nuts • Washers • Turnbuckles • Cotter pins • Screws • Rivets • Plumbing fittings (pipes and tubes)