Riveting in Sheet Metal Fabrication(additive vs subtractive manufacturing Mike)
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Types of Rivets for Sheet Metal
There are several types of rivets suitable for joining sheet metal:
Solid rivets - These are one-piece rivets made entirely of metal. Common materials include steel, aluminum, copper, and Monel. They are the simplest and most cost-effective rivets.
Blind rivets - These contain a mandrel inside the hollow rivet body. As the rivet is set, the mandrel is pulled into the rivet body, flaring the rivet shank. This allows riveting in only one direction from the accessible side. Blind rivets are popular for field assembly.
Self-plugging rivets - These feature a stem that plugs the hole after installation. This creates leakproof joints while providing solid mechanical attachment. Self-plugging rivets are ideal for joining sheet metal parts that contain liquids or gases.
Specialty rivets - Other options like large flange rivets, drive rivets, and structural rivets are available for heavy duty applications. They come in various head styles and materials.
Rivet Guns for Riveting Sheet Metal
Installing rivets in sheet metal requires a riveting tool or rivet gun. There are several types suitable for different applications:
Hand rivet guns - Lightweight hand-operated tools for occasional riveting. Hand squeeze or plier-grip models are available. Best for small scale, low volume work.
Pneumatic rivet guns - Use compressed air to drive the rivet setting action. Allows high speed, repetitive riveting for production environments. Different models match various rivet sizes and materials.
Battery rivet guns - Cordless electric tools powered by rechargeable batteries. Provide user mobility and convenience without needing compressed air.
Electromagnetic rivet guns - Employ magnetic force to install rivets. Used for specialized applications like explosive environments where electric or air tools could be hazardous. Allows access to confined spaces.
Automated riveting systems - For high volume manufacturing, robots and other automated machinery can install rivets under computer numerical control (CNC).
Sheet Metal Rivet Joint Design Considerations
Proper design is critical for riveted sheet metal joints that perform reliably:
- Rivet diameter should match sheet metal thickness. This ensures the rivet fills the hole and clamps effectively.
- Spacing between rivets should be 3-4 times the rivet diameter. Dense spacing prevents metal distortion.
- Use enough rivets to withstand expected loads. More rivets share and reduce stress on each fastener.
- Orient rivets perpendicular to applied forces. This improves load capacity compared to other angles.
- Use washers to reinforce large or slotted holes and prevent tearing.
- Avoid putting rivets near sheet metal edges. Maintain at least 1.5x rivet diameter edge distance.
- Account for rivet head projection and remove if needed. Flush rivet heads allow smooth joining.
Rivet Installation Process in Sheet Metal Fabrication
Installing rivets properly ensures strong, lasting sheet metal joints. The process involves:
1. Cutting or punching matching holes in the sheet metal parts to be joined. Deburr holes.
2. Clamping parts into the aligned position using jigs, fixtures, or temporary fasteners.
3. Selecting the proper rivet type and size for the application. Consider joint strength needs and material thickness.
4. Choosing an appropriate rivet gun for the rivet size and production volume. Verify its condition.
5. Inserting the rivet into the aligned holes through both sheet metal pieces. The rivet should fit snugly.
6. Activating the rivet gun to upset and deform the rivet shank. This clamps the sheets together tightly.
7. Repeating steps 5-6 to install the remaining rivets in the joint as per the design spacing.
8. Inspecting the finished riveted joint to confirm rivets are fully seated and clinched properly.
Riveting is an efficient, reliable method for fastening sheet metal components that will continue being a staple of fabrication and manufacturing. Understanding proper joint design, setup, and installation procedures results in quality riveted assemblies. With the right approach, rivets produce sturdy sheet metal structures able to withstand years of service. CNC Milling CNC Machining