Riveting in Sheet Metal Fabrication(anodized metal Adam)
- source:BREDA CNC Machining
Types of Rivets for Sheet Metal
There are several types of rivets used for sheet metal fabrication, each suited for different applications:
- Solid rivets: These are the most common type, made of malleable metal that is deformed on both ends during installation. Aluminum and steel are commonly used.
- Blind rivets: These have a hollow end that is collapsed by a rivet setting tool. Used where access is only available from one side of the workpiece.
- Self-piercing rivets: As the name suggests, they pierce and join layers of sheet metal in a single operation without pre-drilled holes.
- Drive rivets: They are installed by hammering rather than mechanical compression and often have large flange heads.
- Structural rivets: They are high-strength rivets that meet structural engineering specifications. Primarily used in steel construction.
Sheet Metal Riveting Process
The process of riveting sheet metal components generally involves the following steps:
1. Material Selection: Select rivets of suitable material, type, diameter and length based on the sheet metal stack-up and strength requirements.
2. Hole Preparation: Accurately drill or punch holes as per rivet specifications so that the rivet shank passes through freely but the head seats snugly. Deburr holes.
3. Parts Alignment: Align and clamp the sheets to be joined so that the holes match perfectly. Use jigs and fixtures to aid alignment.
4. Rivet Insertion: Insert the rivet shank through the prepared holes. The parts must rest flush against the rivet head.
5. Rivet Setting: Use a riveting hammer, squeezer, or specialist tool to upset and flatten the protruding end of the rivet. This expands the rivet and clamps the sheets together.
6. Inspection: Check for defects such as cracks, improper deformation, joint misalignment, or loose rivets. Any defects must be reworked.
7. Finishing: Grind flush any uneven or protruding rivet ends to achieve a smooth finished surface. Deburr as needed.
Equipment for Riveting Sheet Metal
Some important equipment used for riveting sheet metal include:
- Pneumatic rivet squeezers: Powerful tools that compress both ends of the rivet using pneumatic force. Ideal for high-volume production.
- Hand rivet sets: For hammer or squeeze-type riveting in lower volume operations. Use with bucking bars.
- Self-piercing rivet setting machines: Automated systems for installing self-piercing rivets. Include C-frame presses and specialty tools.
- Riveting robots: Programmable robots that automate the riveting process for large parts or mass production.
- Hole punching machines: For quick and consistent hole preparation prior to riveting. Available in benchtop or floor models.
- Jigs and fixtures: Used to securely hold parts in proper alignment during riveting. Essential for accuracy and quality.
- Inspection tools: Such as gauges, magnifiers, and rivet micrometers to verify rivet specifications and joint quality.
Advantages of Riveting Sheet Metal
Some key advantages of riveting for joining sheet metal include:
- High strength: Riveted joints can withstand very high shear and tensile loads before failure.
- Reliability: Properly driven rivets produce durable, permanent joints.
- Vibration resistance: Rivets maintain tight clamping force even under vibrations.
- Quick installation: Automated riveting is fast compared to welding or adhesive bonding.
- Easy inspection: Visual inspection can detect poorly driven rivets.
- Disassembly and rework: Rivets allow non-destructive disassembly for maintenance and rework.
- Material versatility: Rivets work for almost all metals, as well as composites and plastics.
- Improved fatigue life: Correctly riveted joints withstand cyclic fatigue stresses better.
- Corrosion resistance: Proper riveting provides good sealing against corrosion.
- Cost-effectiveness: Lower labor skill is required compared to welding, lowering costs.
With the growth of automation and robotics, riveting will continue being a popular, reliable technique for assembling all types of sheet metal components and products. Proper joint design, hole preparation, and rivet installation procedures are key to achieving high quality riveted assemblies. CNC Milling CNC Machining