Riveting in Sheet Metal with CNC Machines(types of revits Marguerite)

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Rivets have been used since ancient times to join pieces of metal together. While early rivets were handmade and hammered into place, modern manufacturing utilizes computer numerical control (CNC) machines to precisely drill holes and insert rivets with speed and accuracy. For working with sheet metal, CNC riveting offers many benefits over traditional techniques.
How CNC Riveting Works
CNC riveting machines use automated drills and fastening tools to produce riveted joints. The process involves three main steps:
1. Hole Drilling: The CNC machine drills holes precisely matched to the rivet diameter into the stack of sheet metal parts. This ensures a tight fit when the rivet is inserted. Modern machines use automated tool changers to swap between drilling and riveting operations.
2. Rivet Insertion: Next, the machine automatically inserts a rivet into each pre-drilled hole. The rivets may be fed via tubes or on reels to facilitate high-volume production.
3. Upsetting: Finally, an automated riveting head upsets the rivet tails to spread them out and clamp the sheet metal layers together. This may be done with squeezing, hammering or rolling techniques.
The CNC machine repeats these steps rapidly to insert hundreds or thousands of rivets to assemble large sheet metal structures. Precision programming coordinates the hole locations and riveting sequence.
Benefits of CNC Riveting
Automated CNC riveting offers many advantages over manual processes:
- Speed: CNC machines can insert rivets much faster than human operators. Riveting rates of 1-3 rivets per second are typical.
- Consistency: The automated process provides consistent spacing, alignment and force, resulting in uniform high-quality riveted joints.
- Accuracy: Modern CNC machines have positioning accuracy within 0.005 inches (0.13 mm) for drilling precision holes.
- Flexibility: CNC programs can accommodate any rivet pattern, spacing and sequence required for the application. Changes can be made instantly.
- Complexity: CNC automation handles complex joint geometries and nested riveting locations that would be challenging or impossible to rivet manually.
- Strength Testing: CNC riveting machines can perform pull tests on samples to verify joint strength for quality control.
- Efficiency: Automation reduces labor costs and frees workers from challenging manual riveting tasks.
Applications of CNC Riveting
CNC riveting excels at assembling large or high-quantity sheet metal fabrications. Common applications include:
- Aircraft assemblies: Fuselages, wings, tails and other components use thousands of rivets. CNC automation produces airworthy riveted joints.
- Automotive parts: Doors, body panels, frames and chassis components often utilize CNC riveting.
- Electronics enclosures: Rivets assemble sheet metal boxes, racks and housings for electronics.
- HVAC ducting: Spiral ducts, vents, dampers and other HVAC components involve extensive riveting.
- Building products: Metal roofs, siding, gutters and architectural panels use rivet fastening.
- Furniture: Lockers, shelving units, desks and metal furniture employ CNC riveting.
- Appliances: Washer/dryer shells, refrigerator panels and other appliances are riveted with automation.
An alternative to rivets is welding, but riveting avoids concentrated heat distortion making it ideal for many applications. The flexibility of automated CNC machines enables riveting of small batches or custom jobs economically.
Rivet Types for CNC Machines
Many varieties of rivets work with CNC equipment:
- Blind Rivets: These have hollow ends allowing insertion through only one sheet surface. Mandrels expand the rivet.
- Drive Rivets: Also called open-end rivets, these are hammered into pre-drilled holes in both sides of a sheet stack.
- Self-Piercing Rivets: Rather than pre-drilling, these punch through stacked sheets and interlock. Often used for dissimilar metals.
- Structural Rivets: Used for high-strength critical joints, these have large heads and tight dimensional tolerances. Aircraft grade rivets are one example.
- Pop Rivets: Widely used for light duty applications, these snap into place using a hand tool when the mandrel is pulled.
- Solid Rivets: Made from solid wire rather than hollow tubing, these provide a flush exterior surface.
- Semi-tubular Rivets: Similar to solid rivets but with partially hollow ends for easier driving into the joint.
With programmable CNC machines, the optimal rivet style and material can be selected for each application's requirements.
Programming Considerations
To leverage the full capabilities of computer-controlled riveting, programming should address:
- Hole patterns: Desired locations and sequence of rivet holes.
- Sheet materials/thicknesses: Matches drill size and rivet length to the stack.
- Joint accessibility: Optimizes approach angle of tools based on part geometry.
- Quality checks: Measures rivet strength and verifies hole alignments.
- Fixtures: Holds parts securely in optimal orientation for automated processing.
- Tool changes: Swaps drill bits and rivet setters needed for the sequence.
- Efficiency: Minimizes non-value motions of the machine.
- Documentation: Records program inputs, tooling and quality checks for the job.
With proper CNC programming, machines can rivet sheet metal components with great speed while maintaining high precision. This makes riveting one of the most productive and cost-effective joining methods for sheet metal fabrication. CNC Milling