Producing High Quality Rivets with CNC Machines(online machining quote Cash)
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What are Rivets?
A rivet is a mechanical fastener that consists of two main parts - a smooth cylindrical shaft and a head. The shaft is inserted into holes drilled or punched into the materials being joined. The rivet is then deformed to create a second head, clenching the materials together.
Rivets come in a wide variety of styles, sizes and materials. Common types include solid and blind rivets, which are tubular with one closed end. Pop rivets have a mandrel through the center that is pulled to flare out the rivet. Drive rivets are installed using a hammer rather than mechanical setting.
Benefits of Rivets
Unlike welding, fastening with rivets does not involve high heat that can compromise material integrity. Riveted connections have some flexibility to absorb vibration and shock loads. Installation only requires access to one side of a joint.
Rivets made of softer materials can be used with brittle materials like glass and ceramics. Joints can be disassembled relatively easily by drilling out the rivets if needed. Weight savings can also be achieved versus alternatives.
CNC Machining of Rivets
Producing rivets has traditionally relied heavily on manual labor, but modern CNC machines bring higher productivity, precision and consistency.
CNC lathes equipped with live tooling can completely machine rivet blanks from bar stock in one setup. After facing off the end, the shaft is turned down to the required diameter and overall length. Undercutting the head and turning grooves for locking rings can also be performed.
Secondary operations like thread rolling, drilling cross holes and slotting are executed using the lathe's live tooling. This eliminates the need for separate secondary processing, increasing efficiency. Live tooling uses powered rotating cutters allowing machining of complex features beyond the capabilities of the lathe spindle alone.
Rivet headers form the characteristic head on one end of the rivet blank. Headers may be single-stroke or multi-stroke designs. In a CNC header, the ram stroke, heading force and dwell time are programmable to precisely control the rivet head dimensions. This helps maintain tight tolerances and minimizes secondary operations.
For large volume production, CNC machines arranged in-line can rapidly transform raw material into finished rivets. CNC enables changing rivet lengths and styles via programming rather than mechanical changeovers. Rivet quality and consistency is improved compared to manual methods.
Optimizing Rivet Production with CNC
There are several ways CNC improves productivity and rivet quality:
- CNC machines allow very fast cycle times. Highly optimized tool paths maximize material removal rates. Quick tool changes minimize non-cutting time during production runs.
- Automated loading/unloading of parts is easily integrated with CNC equipment. Conveyor systems and part handlers can work continuously without operator intervention.
- Precision machining reduces secondary benchwork. Complex features like threads and cross holes are completed in one setup. Finalhead forming is consistently accurate with minimal flash.
- Quick changeover between jobs by altering programs rather than mechanical fixtures. Many rivet dimensions can be adjusted via CNC controls without affecting cycle times.
- Monitoring equipment like automatic gauging probes and tool load monitors can provide real-time feedback ensuring rivets stay within specifications throughout runs.
- Unattended operation for lights-out production. CNC allows machinery to run for extended times with minimal supervision to maximize uptime.
Material Considerations
Rivets are produced from metals including aluminum, steel, stainless steel, copper, brass and more. The raw material must have suitable mechanical properties and machinability. Ductility allows solid rivets to be deformed during installation without fracturing.
Aluminum alloys are popular for aircraft and other lightweight applications. Corrosion resistant stainless steel is used in harsh environments. Hardened steel provides very high shear strength for heavy loads. The material choice depends on the service loads and application requirements.
Machinability considers how easily the stock can be cut cleanly by the available tooling. Long stringy chips are undesirable as they can lead to built-up edge on the cutting tool. Built-up edge results in poor surface finish, reduced tool life and dimensional errors. Materials with good chip control are preferable for production machining.
Conclusion
From tiny fasteners securing delicate electronics up to large structural rivets, CNC machines provide the productivity and precision needed for manufacturing high volumes of quality rivets. Continued advancements in CNC technology will further improve capabilities for producing this vital component efficiently and cost-effectively. CNC Milling CNC Machining