SPR (Self-Piercing Riveting) is an advanced cold-forming solid-state joining technology. Its core principle is: a special rivet directly pierces the upper sheet metal under pressure and plastically expands in the lower sheet metal to form a mechanical interlock structure, completing the connection in one step. The whole process features no high temperature, no smoke, and no thermal deformation.

Its core advantages subvert traditional joining processes:

• Full compatibility with dissimilar materials: It reliably connects steel-aluminum, aluminum-aluminum, steel-composite materials, and multi-layer sheets, solving the industry pain point that spot welding cannot adapt to lightweight materials.

• Zero damage with cold process: No heat-affected zone, no damage to material plating and mechanical properties, avoiding thermal deformation failure of aluminum alloys and composite materials; the fatigue strength of the joint is more than 30% higher than that of traditional spot welding.

• High efficiency and convenience: No pre-drilling required, and the riveting time of a single rivet is ≤ 2 seconds, adapting to high-cycle automated production.

• Environmental protection and safety: No sparks, no smoke, low noise, complying with green manufacturing requirements; meanwhile, the joint has excellent sealing performance, suitable for waterproof scenarios such as battery pack housings.

In the lightweight manufacturing of new energy vehicles, SPR technology is the core key for lightweight structural assembly, covering two core fields: vehicle body and battery.

• Lightweight body assembly: Doors, hoods, chassis structural parts, and integrated die-cast body components of all-aluminum bodies and steel-aluminum hybrid bodies rely on SPR for reliable connection. It ensures body strength while reducing vehicle weight by 10%–15% and improving cruising range.

• Battery pack manufacturing: Lightweight components such as battery pack housings, trays and upper covers are mostly made of aluminum alloy or composite materials. SPR requires no drilling and no heat input, avoiding housing deformation and sealing failure, ensuring the IP67 waterproof rating of the battery pack, and enhancing the vibration and impact resistance of the battery pack structure to adapt to complex road conditions.

Robotic automation integration is the core competitiveness of Eunice’s SPR solution. Centered on 6-axis industrial robots, the company integrates an intelligent SPR riveting unit, a visual guidance system and a process parameter optimization module to build a high-precision, high-flexibility automated riveting system.

• Visual guidance: AI-based visual positioning automatically identifies workpiece positions and riveting points, compensates for assembly deviations, and achieves riveting accuracy of ±0.1 mm to ensure stable quality of each rivet point.

• Flexible production: The system supports rapid model changeover; by replacing riveting dies and calling programs, it adapts to riveting needs of different models and components, supporting multi-variety collinear production.

• Intelligent monitoring and traceability: Real-time collection of riveting pressure, stroke, time and other parameters, generating quality data reports to achieve full-process traceability; automatic alarm for abnormalities to ensure product consistency.

• Compact design: The lightweight and modular riveting unit is suitable for operations in narrow spaces, perfectly solving riveting challenges in complex areas such as the inside of battery packs and vehicle body cavities.

Eunice’s integrated SPR solution helps customers break through lightweight manufacturing bottlenecks with three core highlights: AI + vision technology, global service network, and comprehensive value creation.

• AI + vision empowerment: The company integrates industrial large models and visual algorithms to realize automatic optimization of riveting process parameters and intelligent defect identification, continuously improving riveting quality and stability, and leading the intelligent upgrade of cold joining processes.

• Global service network: Relying on domestic offices in Suzhou and Shanghai and overseas market service experience, it has built a global service system to provide local solution design, equipment delivery and operation & maintenance support for customers at home and abroad, ensuring efficient project implementation.

• Value presentation: Eunice’s SPR solution helps customers achieve three core values: lightweight weight reduction to improve cruising range, automated production to reduce costs and increase efficiency, and reliable joining to enhance product safety and durability. It has provided lightweight joining solutions for many new energy vehicle manufacturers and battery enterprises, and is widely recognized in the industry.

Lightweight is an eternal theme of new energy vehicles, and reliable joining is the core guarantee of lightweight. With the characteristics of adapting to dissimilar materials, high efficiency, reliability, green intelligence, Eunice’s SPR cold joining technology has become the optimal solution for lightweight manufacturing of new energy vehicles. In the future, the company will continue to iterate SPR technology and automated integration solutions, deeply cultivate process demands in the new energy field, empower the lightweight industry upgrade with the cold joining revolution, achieve a perfect balance between lightweight and safety for every new energy vehicle, and rivet a bright future for new energy intelligent manufacturing.