Uses for Rivets in CNC Machining(galvanized vs galvannealed Erica)
- source:WEINBERG CNC Machining
What are Rivets?
A rivet is a mechanical fastener that connects two or more materials by inserting a metal rod through aligned holes in the materials. The rivet rod has a head on one end that is larger than the hole. The tail end is then mushroomed or flattened to create a second head, securing the materials.
Rivets come in various materials, sizes, and head styles for different applications. Common materials are aluminum, steel, copper, and titanium. Head styles include round, flat, countersunk, and specialty designs. Rivet sizes are measured by the diameter of the rivet rod.
Popular Uses of Rivets in CNC
Aircraft and Aerospace Components
The aerospace industry relies heavily on rivets to assemble airplane fuselages, wings, and other components. The light weight yet high strength of aluminum rivets makes them ideal for reducing aircraft weight. CNC machining is used to drill precision rivet holes and dimples into aluminum sheets. Rivets then permanently fasten the panels together into a rigid structure.
Steel rivets are ubiquitous in metal fabrication for assembling automotive parts, machinery, appliances, furniture, and other products. CNC routers and laser cutters automate cutting of sheet metal and structural steel components. Rivet holes are also CNC machined into the parts, which workers then rivet together into finished products. The strength and durability of steel rivets resist vibration and shock loads.
Boats, Ships, and Offshore Platforms
Marine grade rivets made of stainless steel or titanium provide corrosion resistance for building boats, ships, barges, and offshore oil rigs. CNC plasma cutters shape steel plate and structural beams used in vessel construction. Stainless steel rivets permanently fasten the cut components together for a watertight seal. The saltwater corrosion resistance and high clamping force of stainless rivets prevents loosening over decades of service.
Piping, Plumbing, and Tubing
Copper and brass rivets reliably join copper pipes, tubes, fittings, and plumbing fixtures. Soldering is unsuitable for copper plumbing joints because the solder can crack over time. Copper rivets form strong, permanent, and vibration-resistant connections between components. CNC machining centers perform excellent rivet hole drilling in copper and brass parts thanks to advanced rigid tapping capabilities.
Miniature aluminum or steel rivets are ideal for assembling electronic devices because they are electrically conductive for grounding circuits. Rivets also minimize electromagnetic interference that degrades circuit performance. CNC machining accurately drills tiny rivet holes into computing, communications, and consumer electronics components made of metal and plastics. The rivets are then pressed in to permanently assemble the products.
Signage, Enclosures, and Housings
Rivets offer a decorative touch for signage lettering and logos cut from metal by CNC routers or laser cutters. Countersunk rivets allow smooth exterior surfaces. Riveting also assembles the cut metal sign components into sturdy, long-lasting structures. For electronic enclosures and control panel housings, rivets provide durable assembly while allowing disassembly for interior access or repairs. Stainless steel rivets withstand outdoor weathering on signs and structures.
Key Advantages of Rivets in CNC
Once installed, the mushrooming of the rivet tails locks materials together permanently. Rivets do not loosen over time like threaded fasteners. The high static strength and reliability of riveted joints are crucial for aircraft, infrastructure, and critical machinery. Loose fasteners can cause catastrophic failures.
The combination of friction and clamping force makes riveted joints resistant to vibration and shock loads. Riveting provides robust fastening for automotive, aerospace, and marine applications that experience dynamic loading. Rivets maintain their tight grip even under intense vibration.
Certain rivet materials, such as stainless steel and titanium, resist corrosion in harsh environments like offshore marine applications and chemical plants. Stainless steel resists saltwater corrosion while titanium is both lightweight and extremely corrosion-resistant. This durability prolongs service life.
High Shear Strength
Rivets exert strong clamping force to resist shear loads parallel to the plane of fastened materials. The friction between rivet shanks and hole walls give rivets excellent shear strength. Riveted joints maintain integrity under shear loads that can cause other fasteners to slip and fail.
No Special Tools Needed
Installing rivets only requires simple hand tools like hammers and bucking bars. For production assembly, pneumatic rivet guns make installation fast and efficient. Rivets do not need the power drills, wrenches, torque monitoring, or complex training required for threaded fasteners.
With practice, workers can rivet components together rapidly by hand or machine. This allows high-volume production. Riveting also facilitates fast field repairs compared to slower bolted connections. Quick installation bolsters construction, manufacturing, and maintenance productivity.
Most rivets are made from lightweight aluminum alloys, adding minimal mass to assemblies. Steel and titanium rivets are also lighter than most bolts and screws of the same strength. Weight reduction is especially critical in aircraft where excess mass hampers performance and fuel economy.
Simple rivets cost a fraction of threaded fasteners. And unlike consumable fasteners like plastic push pins, rivets are permanent and reusable. The low cost makes rivets economical for high-volume production. Lower assembly costs mean lower prices for consumers.
Riveting Tips for CNC Machinists
Use the correct rivet material and plating for the operating environment. This prevents corrosion related failures.
Match the rivet head style - round, flat, countersunk - with the parts being joined. This ensures proper seating and head clearance.
Ensure rivet length leaves 1/16 inch grip length after installation, allowing the tail to mushroom properly.
Deburr holes thoroughly. Sharp edges can scrape off rivet plating during insertion.
Use plastic or soft metal Mandrels when riveting softer materials like plastics, fiberglass, or thin sheet metal to prevent hole damage.
Lubricate rivets and holes with light oil or wax to ease insertion and prevent galling of aluminum rivets.
Select the minimum rivet diameter needed for required shear strength to avoid unnecessary stress concentrations around holes.
Set rivets perpendicular to the workpiece surface for maximum strength. Use rivet alignment tools if needed.
Inspect set rivets to ensure proper seating and full tail deformation. Replace underset rivets.
Plan rivet patterns to distribute load paths evenly across assemblies. Clustered rivets can cause distortion.
Rivets Remain a Trusted Fastener for CNC
Despite the rise of automated fastening methods like welding, clinching, and adhesives, humble rivets continue to play an indispensable role in CNC machined products. The unique benefits of rivets like quick installation, vibration resistance, and corrosion resistance ensure riveted joints remain a pillar of fabrication and assembly. With care and expertise, machinists can leverage rivets to optimize the durability, reliability, and cost-effectiveness of CNC projects across every manufacturing sector. CNC Milling