Introduction (non ferrous metal Moore)

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Rivets are one of the most versatile and commonly used fasteners in manufacturing, especially in metal fabrication. A rivet is a mechanical fastener that joins two or more layers of material by inserting a metal shaft through aligned holes in the layers and mechanically deforming the protruding end to clamp the layers together. Rivets come in a wide variety of head styles, materials and installation methods to accommodate many different applications.
In computer numerical control (CNC) machining and manufacturing, rivets serve numerous important functions and are used extensively. This article will provide an overview of some of the top uses and applications for rivets in CNC and discuss the benefits they provide.
Permanent Mechanical Fastening
One of the primary uses for rivets in CNC is to provide permanent mechanical fastening of metal components and assemblies. Unlike welds, rivets can join dissimilar metals and allow some movement between parts. And unlike threaded fasteners, rivets form a permanent connection that won’t loosen over time from vibration. The mechanical clamping force of properly installed rivets also produces joints with excellent fatigue life.
Rivets are commonly used to assemble parts made from sheet metal in CNC machining. Installing rivets with access to only one side of the workpieces is also simpler compared to bolts or screws. And with specialized CNC riveting equipment, robots can precisely insert rivets for automated high-volume production.
Joining Dissimilar Materials
Another major application of rivets is joining metals to other materials like plastics, composites, glass and ceramics. The range of rivet materials available, which includes aluminum, steel, stainless steel, copper and more, allows rivets to form strong joints between dissimilar material combinations. Using adhesives with rivets further improves joint strength.
Rivets are an optimal fastening method when a permanent joint between a metal and another material is needed. They eliminate concerns over galvanic corrosion that can occur when metals are fastened together with screws or bolts. Rivets also evenly distribute clamping forces over joint surfaces.
Blind Riveting
Blind rivets are a specialized rivet variation used extensively in CNC. Unlike solid rivets, blind rivets can be installed from only one side of a workpiece without access to the back. Blind rivets are composed of a rivet body, mandrel and head. To install, the rivet is inserted into pre-drilled holes, and the mandrel is pulled to deform the body and form the rivet head.
Blind rivets make rivet installation feasible in situations where only one surface is accessible. This allows riveting of finished assemblies and hollow frames or tubes. CNC-machined and 3D printed plastic mandrel rivet installation tools are commonly used.
Rivet Nuts
Rivet nuts provide strong thread inserts that can be installed into sheet metals using riveting techniques. A rivet nut is composed of a rivet body with an internally threaded hex head. To install, the rivet nut is inserted into a hole and the body is mechanically deformed with a rivet setting tool.
Rivet nuts allow threaded fasteners to be used in thin sheet metals too thin for tapping threads. They can also reinforce cracked or damaged tapped holes. Rivet nuts are installed using automated riveting equipment in CNC production applications.
Riveted Joint Design
Proper rivet joint design is critical for structural integrity in CNC applications. Factors like rivet diameter, material, grip length, pitch, edge distance and hole clearance must be carefully selected. The number of rivets in a joint also affects shear and tensile strength. Software tools like hole pattern generators aid optimal rivet pattern layout.
Advanced computer simulations of riveted joint strength are often performed during CNC product design. Fatigue life prediction is also done through finite element analysis. This helps ensure riveted assemblies have adequate service life margins.
One of the advantages of rivets versus welding or bonding is repairability. Damaged or worn riveted assemblies can be disassembled by drilling out the rivets. New rivets can then be installed to return the assembly to service. This makes rivets ideal for equipment maintenance and field repairs.
For critical CNC-machined components, engineers will design in accessibility to rivets to facilitate repairs. This is especially useful for equipment with high availability requirements. Rivet replacement extends service lifetimes and reduces costs.
Along with their functional benefits, rivets also provide an attractive decorative appearance in many applications. The distinctive domed heads of rivets can be polished to a mirror finish or given other surface treatments. Different rivet head styles and patterns also create visual interest.
In custom CNC machined and fabricated metal and sheet metal products, rivets are often left exposed and highlighted as design elements. The artful use of rivet patterns enhances aesthetics and brand identity. Rivets convey quality craftsmanship to consumers.
Rivets deliver unparalleled versatility in joining and fastening across nearly every manufacturing sector. From permanent mechanical fastening to blind riveting and thread inserts, rivets serve numerous essential functions in CNC machining and fabrication. Continued advancement in automated riveting systems and innovations like 3D printed mandrels will further expand rivet applications in the future. When properly selected and applied, rivets will remain core components in CNC products and processes for years to come. CNC Milling CNC Machining