High-Quality Rivets for CNC Machinery(automotive plastic fasteners Honey)
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- source:WEINBERG CNC Machining
Rivet Composition
Rivets come in a range of materials, with steel and aluminum being the most common. Steel rivets provide excellent shear and tensile strength, making them ideal for high-stress applications. Aluminum and aluminum alloys, while not as strong as steel, offer the benefits of being lightweight and highly corrosion resistant.
When selecting rivets, consider factors like the materials being joined, operating environment, and required structural integrity. Aluminum rivets are a good economical choice for many general fabrication purposes, while heat-treated steel rivets are recommended for critical structural joints. Talk to your supplier about material options to find the right balance of strength, weight, and cost.
Rivet Head Styles
In addition to material, the head shape of a rivet impacts its performance and installation. Common head types include:
- Countersunk – Flush rivet heads that sit entirely within a countersunk hole in the top material layer. Provides a smooth finished surface.
- Universal – Rounded low-profile heads that sit flush within shallow countersinks. Minimizes protrusion.
- Dome – Pronounced rounded heads that protrude from the material surface. High shear strength.
- Pan – Flat circular rivet heads with shallow profiles. Good middle ground of strength and compactness.
Consider your assembly method and end-use requirements when selecting a head style. Countersunk rivets are ideal when a flush finish is needed. Dome heads provide maximum strength but also the most protrusion. Pan head rivets offer a good compromise between the two.
Shaft Diameter and Length
Rivet shafts are available in a range of diameters and lengths to suit different material stackups and grip requirements. Using a rivet that’s too short won’t properly join the workpieces, while an overly long rivet wastes weight and material.
Work with your CNC program and hardware to determine the optimal rivet length for each application. Factor in the combined thickness of all layers being joined, plus an additional margin to account for material compression as the rivet sets. Grip length should be around 1.5 times the total thickness but may need adjusting based on materials and rivet style.
Having a range of rivet lengths on hand gives flexibility to handle different fabrication needs. Even within a single assembly, multiple shaft lengths may be required depending on material layers in each location.
Rivet Strength Grade
Rivet manufacturers use strength grades to indicate the clamping force and shear strength capabilities of each rivet type. Higher grades provide more structural integrity for critical joints, while lower grades suffice for general purposes.
Most rivets will carry a strength designation like Grade 2, Grade 5, or Grade 8. The higher the number, the stronger the rivet. Some suppliers may also provide specific shear and tensile strength test data to further characterize rivet performance.
Consult engineering specifications to determine the appropriate rivet grade for each application. Using rivets with insufficient clamping force can compromise joint integrity and increase the risk of fatigue failures down the road. When in doubt, opt for the next higher strength grade to ensure the rivets do not become the weak point in the assembly.
Drive Style
While traditionally installed using manual tools, modern CNC machinery can automate rivet driving for improved efficiency and consistency. There are two main automated riveting techniques:
- Impact Riveting – A powerful reciprocal hammering action compresses and deforms the rivet to flare out the tail. Best suited for softer, more malleable materials.
- Orbital Riveting – Uses a pin that rotates and oscillates in a tight spiral to flare out the rivet tail. Ideal for harder, more brittle materials that could crack under impact riveting.
Be sure to select rivets matched to your CNC machine’s driving method. Rivet material hardness, ductility, driven head type, and accessibility will also influence which installation process yields the best result. Consulting with your machine manufacturer is recommended to dial-in compatible riveting parameters.
Quality Assurance
Reputable rivet suppliers should adhere to quality management standards and perform ongoing testing to ensure consistent material properties and rivet performance:
- Raw Material Certs – Chemical composition and mechanical testing data for rivet materials. Confirms compliance with required material grades and specifications.
- Dimensional Inspection – Sample measurements of rivet head, shaft, tail, and overall length. Verifies dimensional accuracy and uniformity.
- Mechanical Testing – Shear, tensile, stress rupture, and other tests periodically performed on rivet samples. Provides quantitative strength data.
- Process Audits – Evaluation of manufacturing processes and quality checks. Aims to maintain and continuously improve production standards.
Insisting on applicable quality certificates provides assurance you are purchasing consistently high-performance rivets. This testing reduces variability that could undermine CNC automation and assembled part quality.
Achieving Quality CNC-Applied Rivets
Dialing in the optimal rivets for your CNC machinery takes careful consideration of joint requirements, rivet attributes, and manufacturing capabilities. With an understanding of the key factors covered here, you can source high-quality rivets tailored for automated precision joining. The result is maximized joint integrity, improved end-product durability, and streamlined production. CNC Milling
