High Quality Rivets Are Essential for CNC Fabrication(annular snap joints Jesse)

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Computer numerical control (CNC) machines have revolutionized manufacturing by enabling fast, precise fabrication of metal and plastic parts. Whether milling, drilling, turning, or routing, CNC relies on programmed toolpaths to shape raw material into finished components. Proper fixture design is crucial to holding workpieces securely in position during machining operations. Rivets are a versatile fastening solution for assembling jigs, fixtures, and assemblies from metal plates, bars, and parts. Using quality rivets improves the durability and performance of CNC fixtures.
What Are Rivets?
A rivet is a mechanical fastener consisting of a cylindrical shaft and head. Blind rivets contain a mandrel through the center that is pulled to expand the rivet body against the reverse side of the workpiece. Solid rivets must be bucked or upset against a shop head after inserting through the hole. Rivets create permanent joints by cold working rather than chemical bonding. Compared to welding, riveting better handles vibration while avoiding heat-related warping. Popular rivet materials include aluminum, steel, stainless steel, copper, and titanium.
Benefits of Riveted Construction
Rivets offer unique benefits that make them ideal for CNC applications:
- Cost Effective - Rivets provide a economical fastening solution compared to nuts and bolts. Standard rivets can be purchased for less than a nickel each in bulk quantities. Installation labor is also minimal with modern pneumatic riveting tools.
- Quick Assembly - A rivet gun can insert hundreds of rivets per hour, while bucking bars make quick work of solid rivet forming. Riveting is significantly faster than cut threading and bolt tightening.
- Vibration Resistant - The cold forming process work hardens and expands the rivet body tightly into holes. Rivet joints maintain clamping force over time better than threaded fasteners when subjected to vibration or shock loads.
- Wide Material Compatibility - Steel, aluminum, and exotic alloys can be securely joined with the proper rivet material and installation method. Rivets distribute load over a wider area compared to bolts.
- No Loosening - Properly installed rivets form a permanent joint that cannot loosen over time. Rivets are ideal for components that require permanent alignment.
- Improved Appearance - Countersunk rivets provide a smooth surface with no bolt heads protruding. Riveting produces a clean, uniform look preferred for visible applications.
Choosing the Optimal Rivet
With various head styles, materials, and sizes, selecting the right rivet is important for CNC fixtures. Considerations include:
- Shear and Tensile Strength - The rivet material and diameter must withstand shear loads and prevent pullout at maximum fixture loading. Steel and titanium provide the highest strength.
- Grip Range - Blind rivets are available in different grip lengths to accommodate varying material stack ups. Using rivets with proper grip range improves pull strength.
- Head Profile - Countersunk, round head, and flat head rivets allow flush or protruding ends depending on recessing capability.
- Hole Size - Rivet holes must match shank diameter to optimize clamping strength after expansion. Keeping holes within tolerance prevents loose joints.
- Environmental Resistance - Choose stainless steel or aluminum rivets for corrosion resistance if fixturing will see coolants, oils, or outdoor weathering.
Key Riveting Techniques
Best practices for riveting CNC fixtures include:
- Drilling Precision Holes - CNC produces perfectly sized, positioned rivet holes. Program hole patterns into CAM software when designing fixtures.
- Countersinking - Angle drill or countersink holes for flush rivet installation. Set depth precisely to avoid excessive material removal.
- Deburring - Use a chamfering tool or Scotch-Brite pad to break sharp edges around drilled rivet holes for ease of insertion.
- Pressing Rivets - Pneumatic rivet guns drive controlled force for proper deformation. Set air pressure to recommendations for rivet size.
- Bucking Solid Rivets - Cut off excess shank before upsetting solid rivets with a bucking bar and hammer against a CNC machined anvil.
- Checking Pull Strength - Confirm blind rivets are properly set by verifying mandrel breakage and pull-out resistance with a force gauge.
Maximizing CNC Fixture Longevity
Properly installing quality rivets is critical for maximizing strength and longevity of CNC workholding fixtures. Compared to threaded fasteners, rivets excel at maintaining tight joints in demanding machining conditions. Their quick installation also improves production efficiency. With strong shear and pullout resistance, high quality rivets join fixture plates, brackets, stops, and other components into rugged assemblies that withstand years of rigorous service. Whether building modular tab and slot fixturing or custom welded structures, be sure to use rivets suitable for the material and application demands. Strong rivet joints help CNC fixtures maintain hold on workpieces during high speed machining operations. This allows fabricating highly accurate, dimensionally conforming parts over long production runs. CNC Milling CNC Machining