Introduction (engineer drawing Adela)
- source:YESCOM CNC Machining
What are Rivets?
A rivet is a mechanical fastener that consists of two main parts - a cylindrical shaft and a head. The shaft is inserted into pre-drilled holes through the materials being joined. The excess shaft material is then hammered and forged to form the second head. This creates a permanent joint by radially expanding the rivet and clamping the materials together.
Rivets come in a variety of head shapes, materials, sizes and strengths to accommodate different design needs. Common materials include aluminium, steel, titanium and specialty alloys. The strength, weight, corrosion resistance and cost considerations will dictate the best rivet type for an application.
Benefits of Rivets in CNC
Rivets provide numerous benefits that make them a popular choice for CNC machined parts and products:
- Permanent Fastening - Once installed, rivets form a permanent, non-reversible fastening (unlike bolts or screws). This prevents loosening from vibration or loads.
- Strength - Well-designed rivet joints have excellent shear and tensile strength for their size and weight. The riveting process work-hardens the shaft, enhancing strength.
- Reliability - Properly installed rivets produce highly reliable, long-lasting joints. Periodic re-tightening is not needed as with screws.
- Appearance - Countersunk rivets provide a clean, smooth exterior surface. This improves aesthetics for visible components.
- Automation - CNC machines can be programmed to drill rivet holes and install rivets for automated high-speed production.
- Versatility - Rivets come in many styles to accommodate accessibility needs and design constraints.
- Lightweight - Rivets add very little weight versus other fasteners. This makes them ideal for weight-sensitive applications.
- Economical - The raw material and processing costs for rivets are relatively low. Their fast automation offsets initial tooling investments.
Common CNC Riveting Applications
Rivets serve important purposes in many manufacturing and fabrication processes involving CNC machines. Typical applications include:
- Sheet Metal Fabrication - Rivets assemble stamped or bent sheet metal enclosures, brackets, panels, housings, etc. CNC laser/punch machines produce the holes.
- Metal Structures - Trusses, cranes, trailers, and machinery frames use rivets at joints for durability and strength. CNC drills the holes.
- Aircraft Assembly - Rivets hold together aluminium aircraft skins, ribs, stringers and other components. CNC drilling achieves precision hole alignment.
- Appliances - Sheet metal appliance housings and wrappers rely on rivets for cheap, quick assembly. CNC turret punches or lasers perforate the holes.
- Electronics - Rivets assemble external frames and internal chassis for computers, monitors, printers and other devices. CNC punching provides accuracy.
- Automotive - Doors, hoods, trunks and body panels get assembled with rivets. Multi-axis CNC robots can drill and install.
- Pressure Vessels - Rivets help connect round tank sections to form boilers, compressed air tanks, etc. CNC rotary tables position the holes.
- Plumbing/HVAC - Stainless steel rivets assemble sanitary tubing and ventilation ducting that must avoid leakage.
- Heavy Equipment - Excavators, bulldozers, cranes and mining gear rely on rivets for durability in big, vibrating structures.
Maximizing Quality in CNC Riveting
To achieve strong, reliable riveted joints in CNC work, machinists should follow best practices:
- Use the recommended drill size for the rivet’s shaft diameter to minimize play while still allowing assembly. CNC programs control hole precision.
- Account for rivet length in drill depth. Rivets come in many lengths to accommodate material stack-ups.
- Ensure drill perpendicularity. Non-perpendicular holes can compromise joint strength and cause assembly problems.
- Clean holes from debris before riveting. Any contaminants reduce joint strength.
- Use rivet installation tools that apply sufficient force to form heads without damaging materials.
- Stagger adjacent rivets to prevent local material overstressing during installation.
- Apply sealants/adhesives if needed for weather-tight, leak-proof joints.
- Visually inspect finished rivets to confirm proper head formation and clamping.
By following these guidelines, manufacturers can produce high-quality riveted assemblies with CNC automation that maximize joint durability.
Riveting is a proven mechanical fastening technology that continues providing advantages like strength, permanence and reliability in modern CNC applications. With the precision of CNC hole drilling and rivet installation, manufacturers can mass produce optimized riveted components, structures and products. Understanding the various uses of rivets along with proper design and machining practices allows CNC machinists to implement riveting solutions that deliver exceptional quality and performance. CNC Milling CNC Machining