FDS (Flow Drill Screwdriving) is an innovative thermo-mechanical joining process. Its core principle is: the screw rotates at high speed to generate frictional heat with the workpiece, softening the material to produce plastic deformation; the screw then drills in and forms an internal thread, finally completing the fastening connection. The whole process requires no pre-drilling, no nuts, and can be operated from a single side.

Its core process advantages precisely match the requirements of new energy manufacturing:

• Strong compatibility with dissimilar materials: It enables single-layer and multi-layer joining of steel, aluminum, magnesium alloy and composite materials, perfectly matching the material system of steel-aluminum hybrid vehicle bodies.

• Single-side accessibility: It only requires operation from one side, making it suitable for closed cavities, complex profiles, inner battery packs and other areas where double-side operation is impossible — a unique advantage irreplaceable by processes such as SPR.

• High efficiency and detachability: Joining time for a single screw is ≤ 3 seconds with high strength; the joint is detachable for maintenance, reducing after-sales costs.

• No thermal damage: Frictional heat is locally concentrated with an extremely small heat-affected zone, preserving material plating and mechanical properties to ensure structural stability of lightweight materials.

In new energy vehicle manufacturing, FDS is a key technology for steel-aluminum hybrid body and battery pack assembly, covering three major application areas:

• Steel-aluminum hybrid body frame: FDS is used for joining closed cavity structures such as A-pillars, B-pillars and rocker beams, as well as aluminum alloy shock absorber towers to steel bodies. Single-side operation achieves high-strength fastening, ensuring body rigidity and crash safety.

• Battery pack assembly: For housing, upper cover and chassis shield assembly, FDS requires no drilling and no heat input, avoiding deformation and sealing failure. Its detachable feature facilitates later maintenance and recycling of battery packs.

• Chassis component assembly: For multi-layer dissimilar material joining of subframes, suspension parts and other components, FDS ensures stability under long-term vibration, improving vehicle handling and safety.

The automatic tightening system is the core carrier of Eunice’s FDS solution. The company’s robotic FDS system integrates a 6-axis industrial robot, intelligent tightening unit, visual positioning and torque-speed closed-loop control module to achieve high-precision, high-flexibility integration in high-end production lines.

• Precise control: Full closed-loop control of torque, rotation speed and feed rate with torque accuracy of ±0.1 Nm ensures consistent fastening and eliminates loosening and thread slipping.

• Visual positioning compensation: Equipped with a 3D vision system, it automatically identifies joining points, compensates for positioning deviations, and enables precise joining on complex curved surfaces and irregular parts.

• Flexible production: Supports rapid product changeover; different programs can be called to adapt to various models and components, meeting the demand for multi-variety, small-batch and fast-iteration production.

• High beat adaptability: A single station can complete thousands of screw joints per day and can be seamlessly integrated into vehicle assembly and battery pack production lines without extra cycle time.

Eunice’s intelligent FDS solution leads the upgrading of steel-aluminum hybrid body manufacturing with core strengths: integrated hardware-software R&D, talent-driven innovation, and customer transformation empowerment.

• Integrated R&D capability: The company has a complete R&D system for hardware development and software control. Self-developed FDS tightening units and control algorithms deeply integrate mechanical structure, electrical control and process software, adapting to different materials and thicknesses and breaking foreign technological monopolies.

• Talent-driven innovation: R&D personnel account for 70% of the company. The core team has years of experience in automotive joining technology and has developed a customized FDS parameter library for new energy vehicles, supporting in-depth process development and customization.

• Empowering customer transformation: Eunice’s FDS solution helps customers overcome technical challenges in lightweight and multi-material body manufacturing, solves problems such as incompatibility of traditional processes, low efficiency and unstable quality, and supports intelligent and flexible upgrading of body manufacturing to enhance core competitiveness.

Process innovation is the core driving force for the upgrading of new energy vehicle manufacturing. With its unique advantages, FDS has become an indispensable process for steel-aluminum hybrid body production. Relying on professional R&D and full-process service capabilities, Eunice has developed a leading FDS automation solution in China. With the precision of “one-drill forming”, it intelligently locks the lightweight core of new energy vehicles, leads a new paradigm in steel-aluminum hybrid body manufacturing, and injects strong momentum into the high-quality development of the new energy vehicle industry.