High Quality Rivets for CNC Machining and Fabrication(how to weld plastic Berg)
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In this article, we’ll look at what makes a high quality rivet and why it matters for CNC and other precision applications. We’ll also overview the top materials and design factors to consider when sourcing rivets for a CNC machined or fabricated product.
What Makes a High Quality Rivet?
A quality rivet has features that make it reliable for repeated insertion and secure hold across thousands of uses. Key indicators of a high quality rivet include:
- Tight dimensional tolerances - Quality rivets have a shaft and head diameter within +/- .001” of stated size. This ensures consistency and fit.
- High shear and tensile strength - Aircraft grade rivets have shear strengths up to 80,000 psi and tensile strengths to 120,000 psi for solid grip holding power.
- Consistent hardness - Quality rivets maintain consistent hardness of 50 HRC for the shank and 45 HRC for the head. This prevents degradation or warping.
- Smooth surface finish - A smooth, uniform finish allows quality rivets to be inserted and seated with ease. Finish quality of 32 microinches RMS or better is ideal.
- Minimal flash - Flash is the thin metal ridge formed around the rim of the rivet head during fabrication. Quality standards require zero flash or just .002” maximum for neat appearance and assembly.
Why Rivet Quality Matters for CNC
CNC automated machining and fabrication relies on total consistency and precision at every step. This makes rivet quality imperative for several reasons:
- Automated insertion requires dimensional accuracy to match hole sizes and insertion force calibration. Poor rivet tolerances will jam equipment.
- Any defects can translate into scrap and wasted time in high-speed production. Bad rivets must be replaced, stopping production.
- Inconsistent hardness or strength means some rivets can loosen or fail in use. This leads to injuries, liability claims and damages customer trust.
- Poor quality rivets ultimately undermine the benefits of automation, slowing things down rather than increasing consistency and quality.
Key Rivet Materials for CNC Projects
Aircraft grade aluminum, stainless steel and specialty alloys like Monel are common rivet materials for CNC work. Key factors to consider for material selection include:
Aluminum Rivets
- Most common for aircraft and fabrication
- Corrosion resistant and easily workable
- Shear strength around 60,000 psi
- Softer than steel which allows clinching and work hardening
Stainless Steel Rivets
- Highest strength and hardness
- Excellent corrosion and heat resistance
- Shear and tensile strength double that of aluminum
- More brittle than aluminum when clinching
Monel Rivets
- Corrosion resistant nickel-copper alloy
- Strength is 60,000+ psi shear and 100,000+ psi tensile
- Retains properties in high temperature environments
Titanium Rivets
- Highest strength-to-weight ratio
- Shear strength around 100,000 psi
- Extremely corrosion resistant for offshore applications
Carefully consider the operating environment and stress factors like vibration, impact and heat when selecting rivet material. Consulting with your supplier is also advised to match the best rivet material to your specific CNC application.
Rivet Head Styles for CNC Machining
Rivet head shape impacts installation requirements and optimal use:
- Countersunk head - Flat head for flush mount into countersunk holes. Preferred for smooth aerodynamic surfaces.
- Universal head - Rounded dome head for fast insertion into any rivet gun. The most common and versatile head style.
- Large flange head - Provides a wider bearing surface for joints subject to stresses or vibration. Requires a tool with a larger nose aperture.
- Brazier or modified brazier head - High dome head optimized for hand squeezing or hammering instead of rivet gun use.
- Hex head - Allows use of a wrench to tighten down on the rivet head for applications requiring very tight clamping and maximum vibration resistance.
Again, consider the fastening requirements and operating loads when selecting the optimal rivet head design for your CNC machines and fabrication work cells.
Improving Quality and Throughput with CNC-Optimized Rivets
To consistently produce high quality products with automated CNC processes, using optimized and application-specific rivets is a must. Seeking out suppliers specializing in precision CNC rivets allows access to products engineered to maximize machining results and keep your cells running smoothly.
With sound rivet selection and sourcing, manufacturers can avoid defects, downtime and quality issues - allowing CNC processes to improve throughput, lower production costs and deliver exceptional finished products. CNC Milling CNC Machining