Riveting in Sheet Metal Fabrication with CNC(extrusion aluminum Joseph)

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Rivets have been used since ancient times to join sheets of metal together. While welding and other joining methods are common today, riveting is still a popular technique for assembling sheet metal components, especially in aerospace, automotive, and other transportation applications.
The process of riveting involves inserting a cylindrical rivet into pre-drilled holes in two or more layers of sheet metal, and then deforming the tail of the rivet with a riveting hammer or squeezing it with a rivet gun to form a permanent mechanical attachment. This creates a strong joint that can withstand significant loads and vibration.
Riveting by hand is labor intensive, requires skilled workers, and can lead to inconsistencies in quality. Computer numerical control (CNC) machining has automated and improved many aspects of riveting sheet metal. Here are some of the ways CNC is transforming riveting operations:
Precision Hole Drilling
The first step in riveting is drilling holes to accept the rivets. CNC drilling machines use programmed toolpaths and automatic tool changes to accurately and rapidly drill consistent, precision holes for rivets in sheet metal components. Variables like hole diameter, depth, spacing, and pattern can all be controlled through CNC programming. This level of automation and repeatability is difficult to achieve with manual drilling.
Optimized Rivet Patterns
CNC allows engineers to optimize rivet patterns for maximum strength while minimizing number of rivets required. Finite element analysis software can simulate stresses on riveted structures and generate an ideal rivet layout. CNC machines then drill holes and insert rivets according to this optimized pattern. This reduces drilling time, number of rivets, and opportunity for human error in rivet placement.
Automated Rivet Insertion
Specialized CNC-controlled riveting machines are available that pick up individual rivets and precisely insert them into pre-drilled holes at high speeds. This saves significant labor compared to hand insertion of rivets prior to deformation. The machines use servo motors, precision hydraulics, and computer control to orient rivets and drive them into the proper holes in a programmed sequence.
Consistent Rivet Deformation
Deforming or heading the tail of the rivet is critical to creating a tight joint. CNC riveting machines control variables like rivet squeeze force, duration, and deformation geometry to consistently produce optimum rivet heads. This helps ensure uniform rivet compression and strength across the assembly. It also allows engineers to tailor the riveting process for different materials and rivet types.
Increased Throughput & Riveting Capacity
Unlike manual riveting which is paced by human operators, CNC machines can rivet continuously at high speeds limited only by maximum spindle speeds. This substantially increases throughput for high volume riveting applications. And with the ability to run unattended 24/7, CNC provides vastly superior riveting capacity over manual methods.
Improved Quality Control
The programmability, precision, and repeatability of CNC riveting improves quality control versus manual riveting. Dimensions can be checked automatically during the riveting process and out-of-tolerance conditions flagged. This reduces scrap and the need for rework. Traceability is also improved by storing and logging riveting data for each assembly.
Lower Costs
Despite the high initial capital cost, automated CNC riveting can lower overall operating costs in the long run. Reduced labor, downtime, rework, and material waste all contribute to lower per unit costs and higher profitability for manufacturing. And advanced CNC machines have made the technology more accessible to small and mid-size fabrication shops.
Adaptable Production
CNC gives manufacturers flexibility to easily adapt riveting operations to new products. Simply modifying the program code allows different pre-set riveting patterns, hole sizes, depths, etc to be riveted without mechanical retooling. This simplifies prototyping and customizable production runs.
Safer Working Conditions
CNC riveting minimizes the need for workers to physically handle and deform thousands of rivets per day. This eliminates repetitive motion injuries and exposure to fumes or noise from rivet deformation commonly associated with manual riveting. Automated machines create a cleaner and more ergonomic working environment.
Integrated with Other CNC Processes
Many sheet metal fabricators are integrating riveting cells into broader CNC production lines. Pre-cut sheet metal components move from punching/bending machines directly to the CNC riveter for automatic fastening. This creates an efficient, seamless workflow with minimal handling between processes. Riveting can also be combined inline with machining, welding, grinding and other processes.
Evolving CNC Rivet Technology
As CNC riveting has proliferated, machinery manufacturers have brought to market more advanced equipment. This includesProduction Examples
CNC riveting is used across many industries where sheet metal fabrication is common. Here are some examples:
Aerospace - Aircraft fuselages, wings, and other structures include extensive riveting to join aluminum and titanium skin panels to underlying frames and bulkheads. Automated riveting lines assemble major sub-assemblies which are later integrated into finished aircraft.
Automotive - Doors, hoods, trunk lids and exterior body panels on cars and trucks contain riveted joints. Robotic CNC riveting work cells produce these components in auto plants. Riveting is also used in chassis and frame fabrication.
Appliances - Washers, dryers, dishwashers, refrigerators and other home/commercial appliances rely on CNC riveting to join exterior housing panels. Speed and consistency is important for high production volumes.
Building Construction - Prefabricated wall panels, roofing, railings, stair stringers and architectural structures use CNC riveting before transport to building sites for rapid assembly. Rivets allow for modular designs.
Infrastructure - Water towers, silos, power line towers, guard rails and utility shelters often involve riveting of built-up sheet metal and structural shapes during offsite fabrication. Rivets accommodate field assembly.
Furniture - Filing cabinets, lockers, shelving systems and display cases found in offices, schools, hospitals and commercial spaces incorporate CNC riveted sheet metal. Provides durability and modularity.
While one of the oldest metal fastening methods, riveting remains viable for assembling sheet metal in many modern applications. The precision, speed, and efficiency of CNC automated riveting now surpasses manual techniques in most production situations. As the technology progresses and capital costs decline, CNC riveting will likely expand to more small manufacturers, leading to innovation in rivet joint design. CNC Milling CNC Machining