High Quality Rivets Are Essential for CNC Machining(bending metal sheet Herman)
- source:BREDA CNC Machining
What is a Rivet?
A rivet is a mechanical fastener that secures two or more pieces of material together. Rivets consist of a smooth cylindrical shaft and a head on one end. To install a rivet, the shaft is inserted into pre-drilled holes in the materials being joined. The rivet is then deformed on the opposite end to create a second head that holds everything together. This creates a permanent mechanical joint.
Rivets come in a wide variety of sizes, shapes and materials to accommodate different applications and strength requirements. Some common types include blind rivets, drive rivets, split rivets and tubular rivets. Rivets can be made from aluminum, steel, titanium or specialty alloys.
Quality Considerations for Rivets
When selecting rivets, quality is paramount. Here are some key factors that determine rivet quality:
- Strength and durability: The rivet must be strong enough to withstand the expected loads and forces without failing. This depends on the rivet's material properties and mechanical design.
- Dimensional accuracy: The shaft diameter and other dimensions should conform closely to specifications. Precise sizing ensures proper fit into holes drilled for the rivets.
- Consistent deformation: When set, the rivet head should form as intended without cracking or malforming. Proper deformation is needed to create a tight joint.
- Surface finish: The surface should be free of burrs, pits and defects that could impact performance or handling. A smooth finish allows easier insertion into holes.
- Reliable grip range: Blind rivets must properly fill the grip range specified between material layers being joined. This ensures a tight fit regardless of small variations in material thickness.
Why Rivet Quality Matters for CNC Machining
CNC machining utilizes computer numerical control to automate machining tasks like drilling, grinding and riveting. This promises high accuracy and consistency unmatched by manual methods. However, the benefits of CNC machining can only be realized if components like rivets meet tight quality tolerances. Here are some reasons why:
- Automated precision: CNC machines drills holes and inserts rivets to precisely programmed positions and depths. Poor rivet quality undermines this precision.
- Process repeatability: Quality rivets allow CNC automated riveting to produce consistent, high-strength joints time after time. Defective rivets reduce repeatability.
- Optimized cycle time: With quality rivets feeding smoothly, CNC riveting cycles can run without interruption. This optimizes production time and output. Bad rivets jam equipment and cause delays.
- Reduced operator intervention: CNC automation minimizes the need for operators to personally oversee every rivet. But poor rivets increase jamming and exceptions that require operator intervention, negating CNC productivity gains.
- Less rework: Quality rivets installed correctly the first time minimize the need to replace bad rivets and re-drill holes, saving time and cost.
- Tighter tolerances: Precision CNC equipment can hold much tighter riveting tolerances than manual assembly. But this is only possible using high quality rivets sized to exact specifications.
Quality Control for Rivet Manufacturing
Given the importance of rivet quality, manufacturers must utilize stringent production and quality control processes, including:
- Raw material inspection: Incoming metal stock is examined to verify the proper alloy, surface condition and mechanical properties.
- Process monitoring: Rivet heading, shaping and other forming processes are continuously monitored to ensure they stay in tolerance.
- Dimensional gaging: Sample rivets from each batch are measured to validate that the shaft diameter, head proportions, grip length and other dimensions meet specifications.
- Mechanical testing: Rivet samples also undergo load testing to confirm the expected shear and tensile strength for the application.
- Surface finish inspection: Trained inspectors visually examine rivets to check for any small defects in the surface finish and overall quality.
- Statistical quality control: Manufacturers log and analyze quality measurements to identify any deviations from accepted tolerances and trigger corrective action as needed.
When sourcing rivets, CNC machine shops should review supplier quality control procedures and request material certifications to verify their rivets meet necessary standards. This helps prevent quality issues that can undermine the benefits of CNC automated riveting. Investing in quality rivets ultimately pays dividends through optimized CNC machining productivity and improved end product quality. CNC Milling CNC Machining