In automotive manufacturing, engineering machinery, large equipment assembly, and other fields, the tightening quality of multi-bolt connection structures directly determines product stability and safety. Single-spindle tightening equipment can no longer meet the demands of multi-bolt synchronous assembly, leading to the emergence of multi-spindle bolt tightening machines, with high-precision collaborative tightening being their core competitiveness. Many people simplistically understand synchronous tightening as "all spindles starting simultaneously and stopping simultaneously." In reality, true high-precision collaboration requires real-time matching of torque, position, and speed to ensure synchronized tightening progress across all spindles and guarantee consistent preload force for each bolt. The following sections provide an in-depth analysis of the key logic behind high-precision collaborative tightening in multi-spindle bolt tightening machines, covering core concepts, implementation paths, supplementary safeguards, and application value:

I. Core Concepts: Objectives and Misconceptions of Collaborative Tightening

1. Core Objective: To solve the pain point of "uneven force distribution" in multi-bolt assembly through dynamic collaboration of multi-dimensional parameters, achieving uniform and consistent preload force across all bolts and avoiding problems where some bolts are loose while others are overloaded.

   
   

2. Common Misconception: Synchronous tightening is not merely "starting and stopping simultaneously." If only action synchronization is pursued while parameter collaboration is ignored, bolts that complete tightening first will prematurely bear most of the load, making it difficult for subsequent bolts to achieve the preset preload force. This can lead to product structural deformation, connection failure, and other risks, potentially triggering serious safety accidents in heavy-load, high-speed equipment.

II. Key Paths to Achieving High-Precision Collaborative Tightening

1. Fundamental Guarantee: Distributed Architecture with Independent Controllers

Each tightening spindle is equipped with its own dedicated independent controller, rather than a single controller managing all spindles. This design allows torque, position, and speed data for each spindle to be collected and controlled independently and accurately, avoiding delays or errors caused by excessive data processing in a single controller. Each independent controller acts as a "dedicated control unit," capable of responding in real-time to the operating status of its corresponding spindle, providing data support for subsequent collaborative adjustments.

2. Data Hub: Real-Time Data Exchange via High-Speed Bus

Multiple independent controllers form an interconnected network through a high-speed bus, enabling real-time data transmission and sharing. During the tightening process, real-time operating parameters of each spindle (torque changes, position progress, operating speed) are synchronized to the system's master control unit via the high-speed bus. The master control unit performs real-time comparative analysis of all parameters, breaking down information silos between spindles and allowing the system to globally grasp tightening dynamics, providing timely and accurate decision-making basis for collaborative adjustments.

3. Core Technology: High-Precision Servo Drive and Dual Closed-Loop Torque-Angle Control

The servo drive system can adjust the operating speed and output torque of tightening spindles according to controller instructions, ensuring stable and controllable spindle operation. Dual closed-loop torque-angle control enables dual monitoring—the torque closed-loop monitors and adjusts output torque in real-time to prevent torque anomalies; the angle closed-loop tracks rotation angle, corresponding to bolt tightening progress. When the master control unit detects that a spindle is ahead in position, it instructs that spindle's controller to reduce speed and wait for others to catch up; if a spindle lags in progress, parameters are appropriately adjusted to ensure all spindles advance synchronously.

III. Supplementary Safeguard: Adaptive Calibration Function

In different assembly scenarios, bolt specifications, workpiece materials, connection conditions, and other factors change, affecting the torque and angle variation patterns during tightening. The equipment's adaptive calibration function can, before formal tightening, collect relevant parameters through trial tightening and automatically optimize control parameters for each spindle, ensuring the collaborative logic adapts to different assembly requirements. This function not only enhances equipment versatility but also further strengthens the precision and stability of collaborative tightening.

IV. Application Value: Improving Assembly Quality and Stability

1. Ensuring Product Reliability: By ensuring uniform and consistent preload force across all bolts, product assembly quality and structural reliability are significantly improved, reducing rework and repair costs caused by assembly defects.

2. Reducing Human Interference: Automated collaborative control reduces manual operation intervention, avoiding the impact of human factors on tightening quality and improving the stability and repeatability of the assembly process.

3. Adapting to High-Requirement Scenarios: In fields with stringent assembly quality requirements such as automotive chassis assembly, engine cylinder block assembly, and large engineering machinery connections, it has become an important support for enhancing product competitiveness.

The high-precision collaborative tightening of multi-spindle bolt tightening machines is not the result of a single technology but rather a product of multiple technologies including independent controllers, high-speed buses, servo drives, and dual closed-loop control. Its core logic is to achieve dynamic synchronization of tightening progress across all spindles through real-time, accurate multi-dimensional parameter collaboration, ensuring uniform and consistent bolt preload force. As industrial assembly demands for quality stability continue to increase, high-precision collaborative tightening technology will continue to optimize, providing reliable guarantees for high-quality assembly in more industries.