Riveting in Sheet Metal Fabrication(surface finish symbols Derrick)

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Rivets are a common and effective way to join pieces of sheet metal together. They create strong, permanent joints while allowing flexibility in the design and assembly process. Here is an overview of riveting and how it is used in sheet metal fabrication.
What is a Rivet?
A rivet is a mechanical fastener that consists of two main parts - the rivet body and mandrel. The rivet body is a head on one end, a shank, and a second head formed on the other end during the riveting process. The mandrel fills the hollow center of the rivet body and is discarded afterwards.
Rivets are inserted through holes in the materials being joined. The shank of the rivet body is larger than the hole, while the mandrel fills the rest of the space. As the rivet is compressed using a riveting tool, the excess material squeezes and deforms to create the second head, securing the materials together.
Advantages of Rivets
There are several key advantages that make rivets a popular choice for joining sheet metal:
- Permanent - Once riveted together, the materials are held tightly together and cannot come loose as with screws or bolts. The second head is integral to the rivet body.
- Strength - The compression and deformation during riveting creates a strong joint. Rivets distribute stress evenly for maximum strength.
- Flexibility - Rivets allow more flexibility than welding or bonding. Parts can be disassembled if needed by drilling out the rivets. Riveting also works with more material types than welding.
- Cost Effective - Riveting is fast, automated, and inexpensive relative to other techniques. No consumables or energy input are required.
- Appearance - Countersunk rivets provide a smooth finished look. Rivet heads can be customized for decoration.
Types of Rivets for Sheet Metal
There are various types of rivets suitable for different sheet metal fabrication applications:
- Solid rivets - Most common type, made of steel, copper, or aluminum. After riveting, the mandrel is discarded.
- Blind rivets - Hollow and open on one end. Do not require access to both sides of material.
- Drive rivets - Contain ridges that cut into the materials. Create very secure joints.
- Large head rivets - Have oversized heads to distribute load. Used for softer, thinner materials.
- Countersunk head rivets - Sit flush with the material surface for smooth finish. Requires countersunk holes.
- Split rivets - Split down the center so they can compress. Quick installation but less strong.
- Structural rivets - Made of high-strength steel. Used on critical joints like in vehicles or aircraft.
- Tubular rivets - Resemble small tubes. Mostly decorative.
- Self-piercing rivets - Can pierce and join sheet metal without drilled holes.
Riveting Process for Sheet Metal
The basic process for riveting sheet metal involves drilling holes, inserting rivets, and compressing the rivets to flare out the second head. Here are the key steps:
1. Design and Alignment - The parts to be joined must align properly and holes should be laid out accurately. Jigs and fixtures may be used to hold parts.
2. Drilling - Matching holes are drilled through the materials using drill presses, CNC machines, or automated drilling units. Hole size matches the rivet diameter.
3. Rivet Insertion - Rivets are inserted through the matching holes. Solid rivets are placed with the mandrel inside.
4. Compression - A riveting machine, hammer, or other tool compresses the rivet. This flares the body and forms the second head.
5. Mandrel Removal - For solid rivets, the mandrel is removed and discarded after riveting. The materials are now joined.
6. Inspection - The riveted assembly should be checked to ensure proper seating and adhesion.
Specialized techniques like self-piercing rivets, blind rivets, and large scale automated riveting utilize variations of this process. Proper hole sizes, rivet lengths, and compression ensure optimal results.
Applications of Riveting in Sheet Metal Fabrication
Riveting has many useful applications in sheet metal products across industries:
- Aircraft and aerospace - Rivets are extensively used on airplane and spacecraft bodies and wings. High strength is critical.
- Building products - Sheet metal roofs, siding, trim, and panels are often riveted for durability and weather resistance.
- Electronics - Small rivets precisely join internal parts like computer cases and appliances.
- Automotive - Body panels, frames, and components are commonly riveted, though welding is also prevalent.
- Ducting and piping - HVAC and plumbing uses rivets on cladding, elbows, brackets, hangers and more.
- Furniture and displays - Kiosks, shelving, cabinets, and retail fixtures rely on rivets for assembly.
- Jewelry and accessories - Decorative rivets adorn belts, bags, watches, and other products.
- Kitchenware - Pots, pans, utensils, and equipment use food-safe rivets.
Nearly any application where sheet metal is fabricated involves riveting to some degree for efficient manufacturing. Continued technology advances in automated riveting ensure it remains a staple in fabrication. CNC Milling