The Importance of Quality Rivets in CNC Machining(4 axis cnc Julia)
- source:BAGANZ CNC Machining
What are Rivets?
A rivet is a mechanical fastener used to join two or more materials together. Rivets consist of a smooth cylindrical shaft with a head on one end. The rivet is inserted through pre-drilled holes in the materials being fastened, and the protruding end is then upset, or deformed to form a second head. This creates a solid connection between the rivet and the materials.
Rivets come in a variety of head shapes, sizes, and materials to accommodate different applications and material combinations. Some common types include blind rivets, structural rivets, drive rivets, and tubular rivets. The material is often steel or aluminum, but specialty rivets may use copper, stainless steel, or titanium.
Applications in CNC Machining
In CNC machined parts and products, rivets provide a reliable means of fastening multiple components together. Some examples of CNC machined items that rely on rivets include:
- Aircraft and aerospace components: Rivets are extensively used in the assembly of aircraft fuselages, wings, and other structures where lightweight and reliable fastening is critical.
- Automotive parts: Body panels, frames, and interior components are often joined with rivets. The automotive industry relies on high shear strength rivets.
- Appliances: Internal parts like brackets, supports, and housings are commonly fastened with rivets in appliances. Tubular and blind rivets allow for easy assembly.
- Electronic enclosures: Rivets help assemble the external casings and internal frame supports of electronic devices. Their vibration resistance is important in electronics.
- Construction machinery: Excavators, cranes, and other heavy machinery use rivets to withstand dynamic loads and impacts.
In all cases, the rivets must withstand shear, tension, and vibration without coming loose or failing prematurely. Riveting also allows faster and lower-cost assembly than welding or bolting in many instances.
The Role of Quality Rivets in CNC Machining
Using high-quality rivets from reliable sources is imperative for CNC machined products for several reasons:
- Strength and durability: Quality rivets are made from strong, durable metals and precise manufacturing processes. They have reliable clamping force and shear strength to avoid failure.
- Consistency: Reputable suppliers provide consistent sizing, quality control, and performance across high volumes of rivets. This allows components to assemble correctly.
- Materials compatibility: Proper rivet materials must be matched to the application to prevent galvanic corrosion. Using the wrong rivets can compromise the product.
- Testing and certification: Rigorously tested rivets ensure they meet required specifications for pressure, pull force, shear strength and other parameters. Certifications validate quality.
- Avoiding defects: Faulty rivets with poor metal quality, improper head formation, or dimensional defects can cause connection failures or alignment issues.
- Reputable source: Trusted and experienced rivet manufacturers have the technical know-how to produce flawless rivets at scale. This gives peace of mind.
Clearly, low-quality rivets introduce potential risks during CNC machined product assembly. They can lead to imperfect connections, alignment issues, reduced shear strength, fatigue, and premature failure in the field. The minor upfront cost savings of cheap rivets pale in comparison to the risks of product defects escaping into production.
Standards for Quality Rivets
To ensure rivet quality, CNC machinists should follow established industry standards. Some applicable standards include:
- ASME B18.1 - For inspection of various rivet dimensions and acceptable variations.
- SAE J2270 - Standard test methods for rivets in tension and shear.
- ASTM F467 - Specifies chemical compositions for rivet steels.
- ASTM F468 - Mechanical properties and recommended heat treatments for rivet steels.
- MS/NASM rivet standards - Dimensional, material, and testing standards for rivets used in aerospace applications.
Reputable rivet suppliers manufacture their products to conform to these and other relevant standards. The standards provide a technical reference to verify certification claims and compare technical datasheets.
Inspecting and Testing Rivets
Incoming quality control procedures should be established to inspect rivets and confirm they meet specifications. Some recommended tests include:
- Dimensional checks - Sample rivet lengths, diameters, head dimensions, etc. should be measured and compared to tolerances.
- Material verification - Chemical analysis or hardness testing to validate proper base material.
- Head formation - Check for proper buckling, smoothness, and concentricity.
- Proof loading - Apply a pre-determined load to sample rivets to confirm minimum axial strength.
- Shear testing - Subject samples to shear force and check for minimum shear strength.
- Microstructure examination - For highly stressed applications, examine internal microstructure for defects.
By performing statistical sampling, destructive testing, and micro-inspections on incoming rivets, any quality issues can be identified before the rivets enter CNC machined assemblies.
Finding a Quality Rivet Supplier
CNC machinists should source their rivets from established manufacturers with proven expertise in specialty rivet production. Here are some best practices for selecting a rivet supplier:
- Seek ISO 9001 and AS9100 certified companies.
- Require evidence of rigorous quality control and testing.
- Review technical specifications to ensure suitability.
- Request samples for evaluation before purchasing.
- Ask about engineering support and custom design capabilities.
- Evaluate lead times and availability. Seek local supply chains where possible.
- Examine customer reviews and testimonials for perspective on service levels.
With an experienced rivet partner, CNC machinists can feel confident that their finished products will live up to quality expectations thanks to superior rivets. The few extra cents spent per rivet are a worthwhile investment in performance, reliability, and customer satisfaction.
Rivets serve a simple yet vital purpose in CNC machined components across countless industries. Their role should never be underestimated. Partnering with premium rivet manufacturers and performing due diligence in inspection, testing, and verification is necessary to prevent defects and ensure flawless end products. By following the guidelines in this article on selecting and validating quality rivets, CNC machinists can have continued success with their machining operations. CNC Milling