Quality Rivets for CNC Machines(properties bronze Orville)
- source:YESCOM CNC Machining
What Makes a Good CNC Rivet?
Rivets for CNC applications need to have consistent physical properties and dimensions to ensure uniform results. Key factors that contribute to quality CNC rivets include:
- Material consistency - Aircraft grade aluminum is a common CNC rivet material, providing high strength-to-weight ratio. Consistent aluminum composition and temper delivers uniform hardness, malleability, and corrosion resistance.
- Dimensional precision - CNC rivets must have tightly controlled lengths and diameters. Variations can cause binding in rivet machinery or loose connections. Computer sorting helps achieve highly uniform rivet dimensions.
- Head shape and quality - Rivet heads must be uniformly shaped, free of burrs and defects. This ensures smooth feeding in automated equipment and uniform clamping force.
- Concentricity - The rivet shank must be concentrically aligned to the head to avoid skewed driving and uneven compression. Quality CNC rivets maintain tight concentricity tolerances.
- Surface finish - Smoother rivet finishes reduce friction and wear on CNC machinery. Consistent surface finish also allows predictable flow when compressing the rivet shank.
- Testing and certification - Reputable CNC rivet suppliers perform extensive quality control testing and can provide certification confirming rivet properties and tolerances. This provides quality assurance.
Best Types of Rivets for CNC
- Solid aluminum rivets - Offer the best combination of strength, weight, cost, and machinability for high volume CNC production. Aluminum alloys 2017, 2024, 2117, 5056 are commonly used.
- Blind rivets - Where only one-sided access is available, blind rivets allow for rivet installation and compression from a single side. Often aluminum or steel.
- Drive rivets - These have pre-formed head on one end and are compressed cold using CNC driver tooling. Often used for fast replacement & repairs.
- Specialty rivets - Variations like large head, countersunk head, colored, and self-plugging rivets are used where appearance, flush fit, or other factors are important.
- Stamped rivets - For low cost and weight, stamped steel rivets can be used. Strength is lower than extruded aluminum rivets.
Considerations for Selecting CNC Rivets
- Strength needed - This determines rivet material and alloy choice. Aircraft rivets like 2024 provide high shear and tensile strength. 2117 is moderate strength and lower cost.
- Machine capability - Select rivet diameter and length that machine can handle. Longer and wider rivets require greater compressive force.
- Hole size - Hole diameter relative to rivet diameter impacts drive force needed and how tightly rivet shank fills hole.
- Gripping range - This is the material thickness the rivet can effectively clamp together. Select rivet length to match material grip range.
- Corrosion resistance - Aluminum rivets offer good corrosion resistance for many applications. Stainless steel can be used when higher resistance is needed.
- Appearance - Aluminum or stainless rivets maintain a clean consistent appearance. For color coding, colored heads are available.
- Cost - Solid aluminum rivets offer the best balance of cost versus performance for CNC uses. Alternatives can reduce cost for lower performance needs.
Tips for Quality CNC Riveting
To achieve strong, reliable rivet joints using CNC equipment:
- Use precision drill bits - Accurate hole diameter is critical for optimum rivet engagement. Maintain sharp bits.
- Thoroughly deburr holes - Any debris or burrs can impact rivet seating and cause defectively set rivets.
- Confirm rivet length - Make sure rivet length properly matches material stack up thickness and equipment capabilities.
- Control insertion speed - Moderate fastener feed rates allow proper seating without jamming.
- Apply consistent pressure - Set machine parameters to exert adequate pressure during compression cycle without excess.
- Use impact riveting for tight spaces - Hammer impact tools allow access in confined spaces inaccessible to CNC presses.
- Conduct trial runs first - Test run joints on scrap pieces to fine tune machine settings before production runs.
- Perform regular inspection - Visually inspect set rivets for head formation, material compression, and other defects.
- Consider adhesive when needed - Threadlocking adhesive can supplement rivets when vibration resistance is critical.
With an understanding of rivet qualities and characteristics, CNC operators can dial in equipment and select the optimal rivets to produce high integrity, repeatable riveted joints. Quality CNC rivets, properly driven, will deliver robust and reliable performance. CNC Milling CNC Machining