Full-Automatic Servo Capping Machine Core Working Principle
I. Overall Process Logic
As a professional manufacturer & factory Shilong from China, this capping equipment supplied by our supplier team operates through coordinated linkage of five major modules: conveying & positioning system, automatic cap sorting & feeding system, servo torque capping execution system, electronic closed-loop control system, and defective product rejection system, realizing fully automatic unmanned operation. Supported by real-time torque feedback closed-loop control of servo motors, it completes the whole process of bottle conveying, positioning, cap feeding, precise capping and discharging. Its core difference from pneumatic friction capping machines lies in adopting torque value as the stop criterion instead of fixed rotation cycles or running time.
II. Detailed Working Principle of Each Module
1. Conveying & Bottle Positioning Mechanism
Empty bottles are continuously transported to the capping station by the conveyor belt. Bottle separating cylinders or servo separating screws separate individual bottles to avoid extrusion between bottles.
Flexible clamping cylinders on both sides clamp the bottle synchronously with bottom supporting blocks to fully fix the bottle, preventing rotation, slipping or tipping during capping.
Photoelectric sensors detect bottle presence in real time. If no bottle is detected, the machine suspends cap feeding and capping actions to save consumables and energy consumption.
2. Automatic Cap Sorting & Feeding
Caps stored in the hopper are conveyed by a lifting cap sorter. A forward-reverse screening structure automatically rejects upside-down, deformed and damaged caps.
Qualified caps slide down the chute to the position right above the bottle mouth. The cap separating cylinder releases one cap at a time, which is accurately placed on the bottle thread for pre-capping.
A cap shortage photoelectric sensor performs real-time monitoring. It triggers an alarm and pauses capping when no cap is detected to prevent scratch damage to bottle mouths caused by idle rotation.
3. Core: Servo Capping Torque Closed-Loop Control Principle
Power execution unit: An independent servo motor matched with a high-precision torque sensor drives capping clamps or friction wheels to press and fit the cap.
Real-time torque collection: As the servo motor rotates for capping, the torque sensor collects real-time torque data thousands of times per second and transmits the data to the PLC touch screen synchronously.
Precise stop logic
When the cap thread is fully engaged and the sealing gasket is compressed, once the real-time torque reaches the target torque preset on the touch screen, the control system immediately sends a stop signal. The servo motor halts instantly, and the clamps release to finish capping.
Multiple protection mechanisms
Over-torque protection: If thread jamming or thread slipping causes sudden torque overload, the servo motor reverses and lifts immediately to avoid cracking bottle mouths or scratching caps.
Adaptive rotating speed: The machine automatically reduces rotating speed for slow buffer screwing when encountering misaligned threads or crooked caps to minimize scratches.
Formula storage: Parameters including torque, rotating speed and pressing stroke for different caps can be saved as independent formulas for one-click switching.
After capping, the clamping mechanism releases the bottle, and the conveyor belt transports finished products to the next station.
A rear torque re-inspection sensor conducts secondary detection of sealing torque. Products with insufficient torque (poor sealing) or excessive torque (damaged bottles/caps) will trigger the rejection cylinder for automatic separation.
Qualified bottles flow normally to filling, labeling and cartoning processes.
III. Coordination Principle of Electronic Control System
The whole machine adopts a closed-loop control system composed of PLC, servo drives and human-machine touch screen:
Operators input parameters such as torque, capping speed, pressing stroke and capping delay for different caps on the touch screen and save them as product formulas.
All photoelectric sensors and torque sensors collect real-time station signals and transmit data to the PLC for calculation.
The PLC sends unified instructions to synchronously control the conveyor, cap sorter, servo capping heads and rejection cylinders.
Abnormal data including cap shortage, abnormal torque and bottle jamming will pop up alarm prompts in real time. Production data is recorded, and the machine supports MES system connection to upload capping torque records for full quality traceability.
IV. Core Principle Difference from Ordinary Pneumatic Capping Machines
Pneumatic friction capping machines: Rely on cylinder pressure to generate friction for capping, without torque feedback. Capping is controlled by running time or rotation cycles, resulting in inconsistent sealing tightness.
Servo capping machines: Take torque closed-loop feedback as the core control standard, with controllable torque precision and uniform sealing tightness for every bottle. It supports data monitoring and overload protection functions.
Guangzhou Shilong Machinery Equipment Co., Ltd., a reliable factory, manufacturer and supplier based in China, integrates research, design, development and manufacturing of professional packaging machinery. We introduce advanced global technologies and integrate superior industry resources. As a trusted China manufacturer, factory and supplier of Shilong brand, we provide tailor-made packaging equipment with premium machinery, abundant manufacturing experience and all-round professional after-sales support.
We own a complete industrial chain covering independent R&D, production, sales and after-sales service.
Our factory specializes in developing and producing various packaging machines: bottle washing machines, servo capping machines, labeling machines, sleeve labeling machines, sealing machines, emulsifiers, mixing tanks, water treatment equipment, as well as customized full-automatic & semi-automatic filling assembly lines and other food processing & packaging machinery.
We always adhere to the corporate tenet of strict quality control, credible reputation and thoughtful service. As a leading Shilong supplier, manufacturer and factory from China, we keep developing personalized equipment solutions and comprehensive technical services for all global clients.
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