How a single-head screw locking machine achieves stable feeding and precise fastening of micro-screws through a high-precision servo control system
Publish Time: 2026-02-12
In high-end manufacturing fields such as consumer electronics, precision instruments, and medical devices, the automatic fastening of micro-screws places extremely high demands on assembly accuracy, consistency, and reliability. Traditional pneumatic or simple electric screw-fastening equipment often struggles to handle problems such as jamming, stripping, and breakage of micro-screws. Modern single-head screw locking machines, however, utilize a high-precision servo control system to achieve closed-loop intelligent control throughout the entire process from feeding to fastening, significantly improving the stability and yield of micro-screw assembly. Its core technology lies in the deep integration of servo drive, real-time feedback, flexible control, and system integration.1. Servo-driven feeding system: Ensuring micro-screws "do not jam, stack, or misalign"Due to their small size and light weight, micro-screws are prone to stacking, flipping, or jamming in vibratory feeders or linear vibrating tracks. The single-head locking machine uses a servo motor-driven intelligent feeding module to replace the traditional fixed-frequency vibrator. The servo system dynamically adjusts the vibration amplitude and frequency based on the screw type and the current feed channel status, achieving "on-demand feeding." For example, when the sensor detects screw accumulation at the end of the feed channel, the system automatically reduces the vibration intensity; if there is empty material, the frequency is briefly increased to accelerate material replenishment. This adaptive control effectively avoids damage or misalignment of tiny screws due to excessive vibration, ensuring that only one screw with the correct orientation is fed out each time.2. High-Resolution Servo Electric Screwdriver: Achieving Sub-Millinewton-Meter Torque ControlThe core of the fastening process is the servo electric screwdriver. Unlike pneumatic or ordinary electric screwdrivers, servo electric screwdrivers have built-in high-precision encoders and torque sensors, which can collect rotation angle, speed, and output torque in real time. For tiny screws, the tightening torque is typically only 0.05–0.3 N·m, which is difficult to control precisely with traditional equipment. The servo system, through a closed-loop algorithm, adjusts the motor current every millisecond during the fastening process, ensuring a smooth rise in the torque curve and avoiding stripping or substrate cracking caused by impact loading. Meanwhile, it supports multi-stage locking strategies—such as "high-speed pre-tightening + low-speed precision locking + pressure holding and springback"—which improves efficiency and ensures locking quality.3. Real-time Feedback and Anomaly Diagnosis: Eliminating Missed Locks, Floating Locks, and Broken ScrewsThe high-precision servo system not only executes actions but also continuously "senses" the process status. During the locking process, the system compares the actual torque-angle curve with the preset standard template in real time. If a sudden drop in torque, failure to reach the target value, or an abnormal angle occurs, an alarm is immediately triggered and the fault location is recorded for easy traceability. For brittle materials, a dual protection of "maximum torque threshold + angle limit" can be set to prevent screw breakage. This data-driven intelligent judgment significantly reduces the need for manual re-inspection and improves the reliability of automated production lines.4. Flexible Programming and Quick Changeover: Adaptable to Multiple Varieties of Tiny ScrewsFaced with frequent product changes, the single-head screw locking machine supports quick parameter import through a graphical human-machine interface. Operators only need to select the screw model, and the system automatically calls up the corresponding parameter sets such as feeding frequency, locking speed, target torque, and locking depth. Some high-end models also support remote process recipe distribution via USB or MES system, enabling "one-click production changeover." This flexibility allows a single machine to efficiently handle dozens of micro-screw specifications, meeting the demands of modern manufacturing with small batches and diverse product varieties.5. System Integration and Expandability: Integrating into the Intelligent Production Line EcosystemAs an automation unit, the single-head screw locking machine can seamlessly connect to robotic arms, conveyor belts, or vision positioning systems. For example, after identifying the screw hole position with a CCD camera, the servo system automatically compensates for coordinate deviations, achieving ±0.02mm-level positioning and locking. All locking data can be uploaded to the factory's MES system, forming a complete quality archive that meets ISO or medical industry audit requirements.In summary, relying on a high-precision servo control system, the single-head screw locking machine comprehensively solves the technical bottlenecks of automated micro-screw assembly, from material supply stability and locking accuracy to process traceability and system flexibility. It is not only a tool to improve production efficiency but also a key intelligent equipment to ensure the assembly quality of high-end products.
