High Quality Rivets for CNC Machining Applications(250 surface finish Colby)
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Rivet Materials
The material used for a rivet significantly impacts its strength and suitability for different applications. Here are some of the most common materials used for high quality rivets in CNC machining:
Steel - Steel rivets provide high shear and tensile strength. Low carbon steel and medium carbon steel are common. Steel is prone to corrosion so zinc-plated or stainless steel rivets are used when corrosion resistance is needed.
Aluminum - Aluminum rivets are lightweight and resist corrosion. 6061 is a common aluminum alloy for rivets when high strength is not required.
Copper - Copper rivets are corrosion resistant while still providing moderate strength. These are commonly used in plumbing applications.
Stainless Steel - Stainless steel rivets offer very high corrosion resistance while still providing good strength. Grade 316 stainless steel is commonly used.
Monel - Monel is a nickel alloy that maintains strength across a wide temperature range. Monel rivets are used in demanding, high-temperature applications.
Titanium - Titanium is extremely strong but lightweight. It resists corrosion and is useful in very demanding aerospace applications.
Understanding rivet material properties allows selection of the optimal rivets for the application requirements. Aluminum and stainless steel are common in many CNC machined products.
Rivet Strength Ratings
The strength rating of a rivet indicates the amount of shear and tensile force it can withstand before failure. Higher strength ratings allow rivets to handle more force without pulling apart. Common rivet strength ratings include:
2024-T4 - A medium strength aluminum alloy rating. Handling around 5,000 psi shear strength.
5056-H32 - A higher strength 5,000 series aluminum rating over over 9,000 psi. 50% stronger than 2024-T4 alloy.
A-286 - An age-hardened stainless steel rating with very high shear strength of 50,000+ psi.
AN470 - A common aircraft-grade steel rivet rating with high strength. Similar to A-286 stainless ratings.
Choosing the right rivet rating provides the required strength while avoiding overengineering and unnecessary expense. Review strength needs based on product design and operating loads.
Rivet Head Styles
In addition to materials and strengths, the head shape and style of a rivet impacts function and appearance. Common rivet head options include:
Round Head - A basic cylindrical head which provides a finished look. Common for general applications.
Countersunk Head - A tapered, flat head which allows the rivet to sit flush with the material surface. Used when a smooth surface is preferred.
Large Flange Head- A wide domed head which distributes force over more area. Recommended for soft or weak base materials.
Small Flange Head - A small domed head that sits nearly flush with the material surface. Provides a dressed finish while distributing force.
Brazier Head - A round head with a shallow cup shape to it. Provides an attractive appearance while maintaining strength.
Selecting the right rivet head shape allows proper function while achieving the desired aesthetic result of the finished product.
Key Considerations for Rivets in CNC Machining
Some key factors to consider when selecting rivets for CNC machined products include:
Strength Needs - Consider the shear and tensile loads expected. Select a rivet material and rating to handle required loads with a safety margin.
Environment - Will rivets be exposed to moisture, chemicals or high temperatures that require specialized coatings or alloys? Select rivets accordingly.
Appearance - Does the rivet head need to blend with the surface or stand out as an accent? Pick head shape and material appropriately.
Base Material - If riveting into plastic or other low strength materials, use large flange heads to distribute force.
Cost - Weigh the cost of higher grade rivets against design performance needs. Avoid over-specification which can raise costs.
By carefully considering these factors, CNC machinists can dial in the right rivets for optimized function, appearance and cost-effectiveness.
Quality Processes for Rivet Manufacturing
Producing consistently high quality rivets requires specialized manufacturing techniques and quality control checks:
Wire Drawing - High carbon steel wire is drawn through ever narrower dies to achieve precision diameter.
Head Forming - Pin headers are precisely shaped using cold forging, rotary swaging and other methods.
Heat Treating - Some materials like aluminum and steel alloys are heat treated to improve strength.
Plating/Coating - Steel rivets are often zinc plated while stainless steel receives passivation coating.
Testing - Dimensions, strength, corrosion resistance and other parameters are routinely tested.
Statistical Process Control - Production processes are optimized to produce minimal variance in rivet quality.
By following robust manufacturing and quality control practices, rivet suppliers can deliver the precision and consistency needed for CNC machined products.
In summary, using high quality rivets matched to the design and production requirements is key for CNC machined products. With an array of material, strength, head shape options and rigorous quality control, today's rivets offer the optimized solution for almost any CNC application. CNC Milling