Producing High Quality Rivets with CNC Machines(best cad cam software for cnc router Louise)
- source:GAENOR CNC Machining
What Are Rivets?
A rivet is a two-part mechanical fastener that consists of a smooth, cylindrical shaft and a head. The shaft is inserted through aligned holes in the components being joined and the head is "swaged" or hammered into shape to clamp the components together. The resulting joint is permanent and reliable.
Rivets come in a wide variety of sizes, shapes and materials like aluminum, steel, titanium and more. Some common types include:
- Solid/blind rivets - inserted and swaged from one side for easy automation.
- Structural rivets - used for critical structural joints in aircraft, bridges etc.
- Drive rivets - hammered into shape by a rivet gun for high strength.
- Pop rivets - "pull" type rivets set with hand tools for quick repairs.
For manufacturers, the most important factors are consistently achieving the right mechanical properties, dimensions, head shape and surface finish on every rivet. This is where CNC machining excels.
Benefits of CNC Machining for Rivet Production
CNC (computer numerical control) machining uses programmed computer instructions to automatically control the tools in a machine shop. Some key benefits for rivet production include:
Precision: CNC machines can repeatedly hit tolerances within 0.001 inches, far exceeding human machinists. This ensures every rivet shaft is an exact fit in hole alignments.
Consistency: CNC automation eliminates deviations in dimensions or finishing quality. This results in every rivet having identical specifications.
Speed: CNC machines can produce completed rivets in seconds, while manual methods took minutes per rivet. This allows scaling production up or down easily.
Flexibility: One CNC machine can be programmed to produce various rivet sizes and head shapes just by changing the end mill cutters and tool paths.
Reduced Labor: CNC automation requires minimal human intervention. Skilled laborers can be allocated to more complex tasks.
How Are Rivets Made with CNC Machining?
While the specific steps can vary based on the rivet design, the general CNC machining process for rivets involves:
1. Design: The rivet dimensions, head shape, chamfers, material etc. are modeled in CAD software. The CAD file guides the CNC machine toolpaths.
2. Workholding: Bar stock of the desired rivet material is securely fixtured in the CNC machine so cutting can be performed across the full batch.
3. Milling: End mills and drills of different sizes are used to cut and shape the rivet shafts and heads based on the programmed toolpaths. This can include profiling, contouring, drilling and tapping.
4. Finishing: Secondary abrasive operations like grinding and polishing may be used to refine the surface texture and deburr edges.
5. Quality Inspection: Sample rivets are measured to verify critical dimensions meet required tolerances. Head shape and shaft finish is also visually inspected.
6. Packaging: Accepted rivets are separated from the raw stock and packed for shipment to customers. Rejects can be re-milled if needed.
Tips for Optimizing Rivets on CNC Machines
Here are some best practices machinists use to optimize rivet production on CNC equipment:
- Use tool holding systems like hydraulic or shrink fit chucks to ensure precise, rigid milling.
- Program optimal chip loads, depths-of-cut and feed rates to extend end mill life.
- Utilize high speed machining where possible to minimize cycle times.
- Design custom fixtures that securely locate bar stock while minimizing setups.
- Apply coolant/lubricant to prevent work hardening of material when milling.
- Adjust feed rates and depth-of-cut near edges to avoid chatter and tool deflection.
- Incorporate in-process inspection points to catch any issues before they propagate.
- Schedule production to balance work between multiple CNC machines for maximum output.
By leveraging these CNC best practices, manufacturers can cost-effectively produce large volumes of rivets with the stringent quality and consistency demanded by industries like aerospace, construction, transportation and many others that rely on rivets for structural integrity. CNC Milling CNC Machining