Why Fasteners Matter More Than Ever in Lightweighting Strategies
As electric vehicles (EVs) and aerospace applications push the boundaries of lightweight design, every gram counts in modern designs. Engineers in these sectors know that fasteners – while often overlooked – can collectively contribute significant mass to modern designs. With automotive and aerospace OEMs targeting aggressive weight reduction for performance, energy efficiency, and emissions targets, lightweight fasteners have become a key enabler.
This blog explores how lightweight fasteners have become a key tool for EV and aerospace engineers working with advanced materials.
The Weight Challenge in High-Tech Transportation
In both EV and aerospace sectors, the drive to reduce weight is driven by performance and efficiency goals:
- Electric Vehicles (EVs): Reducing mass improves range per charge, battery efficiency, and dynamic handling.
- Aerospace: Every pound saved can cut fuel costs, increase payload, or extend range-especially in commercial aviation
In the automotive industry, fasteners can account for up to 50% of a vehicle’s total bill of materials1. In some aerospace assemblies, that figure can be even higher due to redundancy and safety requirements.
Materials That Make It Possible: Beyond Stainless and Carbon Steel
This drive to cut weight has caused engineers to move away from traditional steel fasteners in EV and aerospace applications. As a result, lightweight fasteners are now being produced from:
- Titanium Alloys: Exceptional strength-to-weight ratio and corrosion resistance. Common in aerospace and EV battery casings.
- Aluminum Alloys: Lighter than steel, though less strong; suitable for low-load applications in interior panels and enclosures.
- Engineered Polymers & Composites: Used where conductivity isn’t required, such as in plastic housings and insulation supports.
These materials are replacing traditional fasteners in non-critical applications or where localized strength and thermal compatibility matter.
Key Design Considerations for Engineers
- Joint Integrity in Dynamic Environments
Lightweight fasteners must still withstand vibration, thermal cycling, and mechanical fatigue. Thread design, surface coatings, and preload stability all become more critical. - Galvanic Corrosion with Mixed Materials
Pairing metals like titanium or aluminum with carbon fiber or magnesium structures demands careful consideration of electrochemical compatibility. Coated or insulated fasteners are often required. - Installation Challenges
Lighter fasteners made of softer materials may deform under high torque. Engineers must account for clamp load, torque-to-tension ratios, and potential thread galling-particularly in aerospace, where assembly precision is paramount. - Regulatory Compliance and Testing
Fasteners used in flight-critical or high-voltage applications (like EV battery packs) must meet rigorous industry standards.
The Role of Plastics and Composites in Lightweighting
Injection molded plastics and fiber-reinforced composites are key to modern lightweighting efforts. But these materials present challenges for fastener integration, especially with metallic fasteners:
- Thermal Expansion Mismatch: Plastics expand more than metals, which can loosen joints.
- Stress Cracking: Incorrect fastener geometry or overtightening can crack molded bosses.
- Torque Sensitivity: Plastic substrates require controlled torque and often benefit from heat-set or ultrasonic inserts to prevent damage.
Fastener manufacturers are now collaborating closely with injection molding companies to develop insert-compatible designs and non-thread-forming options tailored for high-performance plastics.
Case in Point: EV Battery Modules
Battery enclosures in EVs demand fasteners that are:
- Non-conductive or electrically isolated
- Resistant to thermal expansion cycling
- Lightweight and corrosion resistant
Composite-compatible inserts and titanium screws are often used in battery trays, cooling plates, and cover assemblies. Here, the fastener must perform thermally and mechanically-without adding excess weight.
Conclusion: It’s Not Just About the Fastener-It’s the System
Choosing the right lightweight fastener requires a system-level view: the materials it connects, the environment it operates in, and the way it will be installed. Engineers in EV and aerospace must now treat fasteners not as afterthoughts, but as strategic components in achieving performance, safety, and compliance goals.
As materials and joining methods continue to evolve, staying ahead means understanding how fastener technology fits into the bigger picture of lightweight design.
Where Does CFI Fit In?
For over 30 years, Components for Industry has been a worldwide provider in industrial components and a partner for industrial plastics and composites companies in a number of industries such as Automotive, Aerospace, Appliance and Heavy Industrial. If you want more information about CFI, our industrial components including threaded inserts, contact us at 847-918-0333 or sales@componentsforindustry.com.
- North East Automotive Alliance. How Much of a Vehicls BOM is Represented By Fasteners and Components? Obtained from: https://northeastautomotivealliance.com/the-benefits-of-consolidated-parts-for-vehicle-interiors/ ↩︎
