Uses for Rivets in CNC Machining and Manufacturing(working of spring Lorraine)
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- source:WEINBERG CNC Machining
Aircraft and Aerospace Applications
One of the most common uses of rivets today is in the aerospace industry. Aircraft components, including the fuselage, wings, and other parts are frequently joined together using rivets. There are several reasons why rivets are ideally suited for aircraft assembly:
- Rivets create a very strong, permanent joint that won't come loose over time or due to vibration forces during flight. This is critical for the safety and integrity of the aircraft structure.
- Riveted joints can be disassembled and reworked if needed for maintenance and repairs. This allows for convenient servicing compared to welded aircraft parts.
- Installation and removal of rivets can often be automated using CNC machining for efficiency and consistency in production. Aerospace factories make extensive use of CNC riveting equipment.
- Many aircraft aluminum alloys are not well suited to welding, so riveting avoids metallurgical issues.
From small general aviation planes to large commercial jetliners, rivets remain a fixture in airframe manufacturing.
Metal Fabrication and Assemblies
Beyond aerospace, rivets are ubiquitous in all types of metal fabrication applications. The joining of sheet metal assemblies, such as enclosures, cabinets, racks, and frames, is often accomplished with rivet fasteners. Reasons this remains a favored technique include:
- The hollow nature of rivets reduces weight compared to alternatives like bolts and screws. This makes them ideal for mass production where small savings per unit multiply.
- Installation of rivets is simple and requires little specialty tooling. Pop rivets can often be set by hand.
- Riveting creates a clean look with the join hidden inside the hole. No external fasteners are visible.
- Vibration resistance is excellent, keeping assemblies from coming loose over time.
- Riveted parts can be flat packed for efficient shipping and transport before final assembly.
- CNC machining allows riveting to be automated and precisely controlled for consistent quality and placement.
Many sheet metal fabricators make extensive use of CNC riveting machines and tools to improve productivity. Offline programming handles rivet pattern design and placement.
Securing Plastics, Composites, and Dissimilar Materials
While most commonly used on metals, rivets can also join other material types like plastics, composites, rubbers, and dissimilar material combinations. Benefits include:
- Unlike welding, rivets can join metals to plastics without melting or distortion issues. Riveting avoids chemical incompatibility.
- Plastics and composite materials often cannot be joined well through mechanical fasteners. Rivets provide a solid joint.
- Multi-material assemblies are simplified by using rivets consistently throughout.
- Weight and balance is maintained since rivet size and weight remains consistent between different materials.
Applications like plastic enclosures, composite aerospace parts, and automotive components use CNC controlled riveting for precision and quality. The automated nature provides consistency between different substrate materials.
Permanent Fastening for Durability
For products that require very rugged, permanent fastening, rivets deliver confidence. Examples include:
- Heavy machinery where vibration could loosen screws and bolts over time. Rivets maintain solid joints.
- Outdoor products subject to moisture and corrosion that could degrade threads on bolts.
- Enclosures that should not be opened or tampered with by users. Rivets discourage disassembly.
- Critical structures and joints where fastener failure could have catastrophic consequences.
The one-way installation combined with high shear strength makes riveted connections reliable in demanding environments. CNC control provides precision in placement and setting pressure.
Allowing for Disassembly and Maintenance
While rivets provide a permanent joining solution in most products, their use in machinery and equipment also allows for disassembly when required. Reasons you may want to design in this capability include:
- Allowing access inside assemblies for maintenance, repair, cleaning, or upgrades.
- Enabling replacement of worn or damaged components without scrapping entire assemblies.
- Allowing reuse and reconfiguration of subcomponents to improve sustainability.
- Satisfying regulatory requirements for inspection of internal components.
By drilling out old rivets, assemblies can be taken apart with minimal damage. New rivets can then rejoin components during reassembly. This flexibility makes rivets ideal for large CNC machined equipment.
High Shear Strength in All Directions
Compared to fasteners like screws, rivets have a design advantage of providing high shear strength in all directions around the join. This makes them resistant to forces trying to pivot or rotate joined materials. Applications benefiting from this include:
- Structural frames and braces subject to multi-axis loads. The rivets maintain integrity.
- Components under eccentric loads that could loosen simple fasteners over time.
- Enclosures around heavy, vibrating machinery. Rivets prevent shaking loose.
- Parts needing shear strength for forces in multiple planes at once.
The radial symmetry of the riveted joint provides the same security against shear forces from any direction. This can simplify design and ensure robustness.
Allows for Electrical and Thermal Conductivity
In some unique situations, the ability of rivets to conduct electricity or heat can be beneficial. Use cases include:
- Joining metallic components that must complete electrical circuits across them. The rivets maintain conductivity.
- Applications where some conductivity and grounding across joints is desired for electronics and EMI/RFI shielding.
- Assemblies where heat needs to flow efficiently across riveted interfaces. Such as LED arrays.
This conductivity largely applies to metallic rivets joining metallic substrates. But even plastic rivets offer some thermal conductivity between parts.
Summary: Why Use Rivets in CNC Applications?
While adhesive bonding and welding have taken over many joining applications, rivets continue to play an important role, especially in precision CNC manufacturing. Rivets offer permanent and robust fastening while allowing for disassembly when needed. They are lightweight, streamlined, and reliable over the long term. And automated CNC riveting improves quality control and productivity. For metal fabrication, aerospace, machinery, and other manufactured goods, rivets solve key assembly and design challenges. Their unique benefits and capabilities ensure these time-tested fasteners will continue enabling innovative products. CNC Milling
