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In pharmaceutical packaging lines, filling, plug inserting, capping, and labeling are the core processes. Among them, capping is a key step that ensures the sealing integrity of liquid or solid bottled medicines. The capping machine (also known as a rotary capper or friction-type capping machine) plays a central role in this stage. Whether the machine is properly selected directly affects production efficiency, cost control, and product quality.
This article provides a straightforward overview of how a capping machine works, the main types available, and a practical selection guide for your production needs.
The working principle of a capping machine is both ingenious and efficient. The core process can be divided into four stages:
Bottles that have been filled and capped are conveyed into the capping machine via a conveyor belt. Using a screw or star-wheel indexing device, bottles are accurately spaced at fixed intervals for stable operation.
Once the bottle enters the capping station, V-shaped clamps or belts on both sides securely hold the bottle body (or shoulder). This prevents the bottle from rotating or shifting during the capping process, providing a stable base for tightening.
This is the core stage. A pair of high-speed, counter-rotating friction wheels—usually made of wear-resistant polyurethane or silicone—move inward to contact and press the side of the cap skirt. Through friction, the wheels drive the cap to rotate and tighten onto the bottle’s threaded neck.
When the torque reaches the preset value (controlled by a mechanical clutch or servo motor system), the wheels stop applying force or automatically disengage. The tightened bottle is then released and conveyed to the next process, such as labeling.
Key Feature:
Throughout the process, the friction wheels only touch the sidewalls of the cap—not the top surface—ensuring the printed or tamper-evident parts of the cap remain undamaged. This makes the system ideal for caps with logos, seals, or special top designs.
Semi-Automatic Capping Machines:
Require manual bottle loading and unloading. Lower automation and speed. Suitable for laboratories, pilot production, or small-scale manufacturing.
Fully Automatic Inline Capping Machines:
Integrated into automated packaging lines to complete bottle feeding, capping, and discharge continuously. High efficiency, consistent torque, and reliable operation. These are the mainstream choice for large-scale pharmaceutical production.
Friction-Wheel Type:
The most common design. Two friction wheels perform the capping action. Compact, versatile, and widely used in pharmaceutical and cosmetic industries.
Belt-Type Capping Machine:
Replaces the two wheels with a long, parallel friction belt. The larger contact surface provides gentler torque transmission, ideal for tall bottles or irregularly shaped caps. However, the structure is more complex.
Mechanical Torque Type:
Uses a mechanical clutch and spring system for torque control. Low cost, but precision is limited and stability declines over time.
Servo Torque Type:
Driven and controlled by servo motors for precise torque adjustment and programmable speed curves. Torque data can be recorded and monitored. This has become the standard configuration in modern capping systems.
When choosing a capping machine, it’s essential to verify the following parameters and communicate them clearly with the supplier.
Below we take the Ry-CM Three-Wheel Capping Machine as an example to explain key considerations:
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| Selection Dimension | Key Questions / Parameters | Description & Example |
|---|---|---|
| 1. Production Speed | How many bottles per minute are required? | The Ry-CM model lists a range of 10–100 bottles/min. Actual speed depends on bottle and cap design—always confirm through sample testing. |
| 2. Compatibility | What are the material, type, diameter, and height of your caps? | The most critical factor. The Ry-CM supports standard caps, tamper-evident caps, double-layer caps, and flip-top caps. Provide actual samples for testing. |
| 3. Torque Requirements | What torque range and accuracy are needed? | The machine’s torque control must cover your target range. The Ry-CM uses a frequency converter to control motor speed for torque regulation. For high-precision needs, confirm servo control availability. |
| 4. Control & Data | Is the interface user-friendly? Is data recording required? | The Ry-CM features a touchscreen interface (English/Chinese) displaying speed, output, and alarms. For traceable torque records, ensure the system includes a servo module. |
| 5. Compliance & Cleaning | Is the material 304/316L stainless steel? Easy to clean? | The Ry-CM housing is made of polished stainless steel with enclosed drive mechanisms for better hygiene. Check for sanitary dead corners during inspection. |
| 6. Line Integration | Do inlet/outlet dimensions match your production line? | The Ry-CM measures 2280×1080×1940 mm. Confirm compatibility with your conveyor height and layout. |
| 7. Core Components | Which brands are used for key electrical parts? | The Ry-CM uses high-quality brands like Delta (controller/inverter), SICK (photoelectric sensors), and Schneider (switches)—a reliable indicator of system quality. |
| 8. Supplier Support | Can the supplier offer free bottle-cap testing? | Absolutely essential. Regardless of technical specs, always verify real-world capping performance, torque uniformity, and noise through live or remote testing. |
Never make your decision based solely on brochures or pricing.
Bring your actual bottles and caps to the supplier’s site—or request a live video demonstration. Observe the operational stability, noise levels, and most importantly, measure the torque consistency after capping (randomly test 10–20 bottles with a torque tester).
Choosing the right capping machine is a technical and strategic investment.
By understanding its working principle, clarifying your production requirements, and following the selection criteria above, you can confidently equip your line with a reliable and efficient capping solution.
When evaluating equipment, models such as the Ry-CM Three-Wheel Capping Machine—which provide detailed technical specifications, compatibility data, and branded core components—can serve as a solid reference for performance and reliability, helping you make a truly informed decision.
