Rivets and Their Uses in CNC Machining(bead blast material Astrid)
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What are Rivets?
A rivet is a mechanical fastener that consists of two main parts - a smooth cylindrical shaft and a head. The shaft is inserted into pre-drilled holes in the materials being joined. The excess portion of the shaft extending beyond the hole is then deformed with applied force to form the second head. The force expands the rivet, causing it to flare against the reverse side of the materials. As it deforms, the rivet exerts force on the pieces, clamping them together. This creates a solid, permanent assembly.
Rivets come in a wide range of styles, sizes, and materials to accommodate different CNC machining uses. The most common types are solid and blind rivets. Solid rivets are one piece and require access to both sides of a joint for installation. Blind rivets have a built-in stem that splits and forms the second head without needing backside access. This makes them ideal for CNC applications where only one side is accessible.
Benefits of Rivets in CNC Machining
Compared to other joining methods like welding and screwing, rivets offer unique advantages that make them invaluable for CNC projects:
- Speed and Ease of Installation – Rivets provide a fast way to securely join materials. Holes can be quickly drilled with CNC machines then riveted by hand or with automated riveting systems.
- Ability to Join Dissimilar Materials – The mechanical grip of rivets allows joining of metals, plastics, composites, and other material combinations that can’t easily be welded.
- Vibration and Noise Resistance – Rivet joints dampen noise and vibration extremely well compared to screws. This makes them favored in applications like aircraft and motorsports.
- Consistent Clamping Force – Proper rivet selection and installation ensures uniform clamping across joints, preventing loosening over time.
- Non-Permanent – Rivets can generally be drilled out if disassembly is later required for maintenance or reuse of components.
- Corrosion Resistant – Many rivet materials and coatings provide excellent corrosion resistance for CNC projects exposed to weather and harsh conditions.
Common CNC Machining Applications of Rivets
Rivets serve well across a diverse range of manufacturing and fabrication disciplines. Here are some of the most prominent uses in CNC work:
Aerospace Manufacturing
Aircraft construction relies heavily on rivets to join exterior aluminum skin panels, titanium and composite understructures, landing gear assemblies, and engine components. Riveting offers the durability to withstand vibration while minimizing aircraft weight. CNC milling machines drill perfectly aligned holes then automated riveters or robots install hundreds of rivets to assemble each airframe.
Metal Fabrication
From truck bodies to railcars, large welded structures are reinforced and pieced together with rivets. CNC punch presses and drills make light work of hole-patterning plates and gussets that are then riveted into structural assemblies. Rivets allow modular construction of frames, boxcars, hoppers, and more.
Automotive Parts
Rivets offer solid fastening for sheet metal auto body panels, truck caps and tonneau covers, bumpers, and other components that require stiffness and vibration resistance. CNC laser cutters and routers cut body panels that are then riveted together into sub-assemblies. Rivets also affix hardware like hinges, handles, steps, and trim.
Appliances and Electronics
The outer shells of appliances and electronics must endure significant temperature swings along with vibration. Rivets excel in these conditions while allowing dissimilar material joining. CNC turret punches make light work of piercing precise rivet patterns in sheet metal chassis and enclosures that are then assembled with rivets.
Recreational Products
From playground equipment to bleachers to motorcycle parts, rivets tackle a wide range of recreational assemblies. Their vibration resistance keep components tight. CNC machining centers drill ultra-precise rivet holes in frames and components that are then riveted into durable products.
Plumbing and Hardware
Though welds could suffice, rivets allow modular fabrication and disassembly of plumbing fixtures, shelving units, hand trucks, cabinets, and other products. CNC routers and waterjets contour parts which are riveted for easy field maintenance and cleaning. This same rationale applies to industrial flow racks, work benches, and dust collection systems.
Key Considerations When Using Rivets in CNC Applications
To utilize rivets safely and effectively, CNC machinists should keep the following in mind:
- Select an Appropriate Rivet Style and Material – Consider joint strength needs, materials being joined, installation access, and operating conditions to select suitable rivets. Using the wrong style or material can compromise functionality.
- Maintain Proper Hole Size and Spacing – Drill holes to match the rivet shank diameter. Follow spacing rules to prevent distortion while maximizing joint rigidity. Too many holes can weaken parts.
- Use Backing Plates When Needed – In thin materials, backing plates support the joint to prevent rivet heads from pulling through. Backing also allows larger rivet options.
- Account for Material Thickness Variances – Clamping force is sensitive to material thickness. Consistent stacks and selective shim use ensures proper rivet compression and performance.
- Control Riveting Pressure – Either too much or too little pressure can cause rivets to distort, loosen, or split materials. Dial in tools to recommended settings and visually inspect joints.
- Deburr Holes and Prepare Surfaces – Any burrs or gunk trapped under rivet heads reduces clamping force. Deburring and cleaning hole edges is a must.
Rivets continue to be a go-to fastening solution for CNC shops across countless industries. By understanding their attributes and following best practices, CNC machinists can leverage rivets to build robust, quality products. With the right rivets properly installed, CNC-machined components fit together reliably for the long haul. CNC Milling CNC Machining