Quality Rivets Are Essential for CNC Machines(rubber molding Lena)

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CNC (computer numerical control) machines rely on high quality rivets to hold together metal components securely. Selecting the optimal rivets for a CNC application requires understanding rivet attributes like material, strength, head shape, and installation method. With so many options available, choosing subpar rivets can lead to weakened assemblies and machine failures. This article will examine how proper rivets enable CNC machines to function reliably over many production cycles.
Rivet Materials
Aluminum, steel, stainless steel, copper, and monel are common CNC rivet materials. Each offers distinct advantages:
Aluminum - Lightweight and corrosion resistant but lower shear and tensile strength than steel. Best for temporary fastening.
Steel - Strong and durable for heavy duty connections but prone to rusting. Carbon steel offers high strength while alloy steel provides corrosion resistance.
Stainless Steel - Doesn't rust and withstands high temperatures. More expensive than regular steel and harder to drive. Ideal for corrosive environments.
Copper - Malleable and ductile. Used for electrical conductivity in circuit boards. Not recommended for high stress applications.
Monel - Nickel-copper alloy resistant to corrosion and acids. Often used in marine and chemical plant equipment.
The operating conditions and connected materials will determine which material provides the best combination of strength, longevity, and cost-effectiveness. Consulting an experienced fastener supplier is advised.
Rivet Strength
Two key measurements indicate a rivet's holding power:
Shear Strength - Resistance to sideways or twisting forces trying to slide the rivet through the hole. Measured in pounds or kilonewtons.
Tensile Strength - Resistance to forces trying to pull the rivet straight out of the hole. Also measured in pounds or kilonewtons.
Higher strength rivets made from hardened steel can bear larger shear and tensile loads without failing. This prevents assemblies from coming loose over time. However, too much strength can also cause the rivet to crack the surrounding material. The rivet strength should match the strength of the connected parts.
Rivet Heads
Several head types are commonly used in CNC machinery:
Dome Head - Round and domed for a finished appearance where aesthetics matter. Low profile allows riveting in tight spaces.
Countersunk Head - Flat head which sits flush with the surface for smooth transitions. Requires a countersunk hole.
Large Flange Head- Broad flat circular head which distributes load over more area. Offers excellent resistance to loosening.
Hex Washer Head - Hex shaped head with integrated washer provides high clamping force. Requires hex socket for installation.
Pan Head - Low rounded head with short vertical sides. Provides a neat appearance.
Flat Head - Low profile flat circular head. Good where clearance is limited.
The head shape impacts how loads transfer between parts and the machine's vulnerability to vibrational loosening. CNC designers choose heads suited to each rivet's function.
Rivet Installation Methods
Installation processes must match the rivet's design and equipment capabilities:
Hand Riveting - Manual tools like squeezers and hammers to insert and deform rivets. Gives operator control but is labor intensive.
Pneumatic Riveting - Air powered rivet guns using compressed air to drive and set rivets. Allows high speed automated riveting.
Impact Riveting - Hydraulic or battery powered tools deliver an impulse to set rivets. Portable yet high energy for heavy rivets.
orbital forming - Spinning concave forming heads reform rivet ends into custom shapes. Requires specialized orbital machinery.
The selected method must effectively produce a tight head closure and work harden the rivet shank without damaging the materials. CNC operators should be trained on proper riveting methods for each machine's rivets.
Quality Control Checks
Careful inspection of installed rivets verifies they meet specifications:
- Head shape conformance - Use go/no-go gauges to confirm proper head dimensions.
- Set verification - Confirm the pin has fully set and the head is tight against materials with no looseness.
- Pull testing - Use a hydraulic pull tester to measure rivet tensile strength. Must meet minimum value.
- Shear testing - Test shear strength by applying transverse force to rivet. Compare results to requirements.
- Microstructure - Examine metal microstructure for cracks or flaws in production process.
By performing quality control checks, weak or defective rivets can be identified and replaced before operation. This reduces failures that lead to unplanned downtime.
Properly specified and installed rivets are what literally holds CNC machinery together through years of cycling stress. With so much riding on these small fasteners, choosing quality rivets purpose-built for the application is a wise investment that pays dividends in equipment lifetime and reliability. By understanding available materials, strengths, head configurations, and setting methods, CNC operators can select optimal rivets and procedures to assemble robust, long-lasting machines. CNC Milling