The pillow-type packaging machine, also known as a seam-type wrapping machine, is a horizontal three-side sealing packaging equipment that automatically completes processes such as bag forming, filling, sealing, cutting, and product discharge. It enables continuous packaging for automated production lines in industries such as food, daily chemical, and pharmaceuticals. Suitable packaging items are typically block-shaped, cylindrical, or granular products, such as instant noodles, bread, frozen desserts, and tissues. Packaged product forms include single-item packaging, combined packaging, palletized packaging, and non-palletized combined packaging.
Pillow-type packaging machines in the market can be classified into single-frequency conversion, dual-frequency conversion, single-frequency conversion + single servo, dual servo, and triple servo types based on their transmission mechanisms. Common configurations include single-frequency conversion + single servo and dual servo systems. Both configurations consist of a film-feeding motor and a main shaft motor. In single servo models, the main shaft motor uses a frequency converter, while dual servo models employ servo motors for both axes. However, the operational principles and working mechanisms of these two configurations are largely similar.
The pillow-type packaging machine synchronizes film feeding and product delivery. As illustrated, the film-feeding motor drives the film-transport rubber rollers and longitudinal sealing mechanisms. The film is formed into a tubular shape through the forming device and undergoes longitudinal heat sealing. Simultaneously, products are fed into the tubular film and transported forward through the transverse sealing and cutting stations. The main shaft motor drives the rotary transverse sealing and cutting blades to perform cross-sealing and cutting, producing the final packaged product.
During normal operation, both the main shaft motor and film motor operate continuously, unlike the start-stop control commonly used in vertical packaging machines. The transverse sealing mechanism completes one packaging cycle per revolution, during which the film motor must precisely feed the film to a fixed length or color mark position. These coordinated movements are managed by a PLC-based controller, which represents the core challenge and critical component of the packaging machine's operation.
To meet diverse customer requirements, HollySys Motor Technology Co., Ltd. has developed a series of control systems primarily categorized into compact and modular types.
The compact pillow-type packaging machine controller utilizes HollySys' SC-D228H controller as its core system. This controller offers powerful functionality in a compact design, featuring 12 digital input channels, 12 digital output channels, and 24VDC power supply. It supports data and Chinese character display, keypad input, and integrates "PLC + text display" functionality in a single unit, providing exceptional cost-performance ratio and flexibility.
The modular pillow-type packaging machine controller adopts a PLC + touchscreen configuration. Built around HollySys' micro modular PLC, this system offers robust functionality and flexible expansion capabilities with 220VAC power supply and built-in 30W DC power (24VDC/12VDC). It supports expandable digital I/O up to 96 points. The 7-inch true-color touchscreen offers higher resolution and size compared to standard 5.7-inch screens, supports recipe storage for 50 product models (each storing 11 parameters including product name), and enhances user convenience.
To address the challenge of synchronizing film feeding with the main shaft's rotational cycle, advanced motion control algorithms implement electronic cam following functionality between the main motor and film motor. This software-based solution achieves unified control of shaft sealing and film feeding. With a 120-line encoder, bag length control accuracy reaches ±2mm, improving to ±1mm with a 2000-line encoder. Packaging speeds range from 0 to 300 bags per minute.
Beyond basic functions like color mark selection/tracking, misalignment detection, and temperature alarm, the system supports advanced controls for coder heating, marking position, nitrogen filling position, and duration. Parameter settings allow configuration for single/dual servo controllers. Additional features include automatic bag length measurement for color-mark films and automatic film adjustment, eliminating the need for manual color mark and knife position calibration, saving time and materials.
The system also provides four-channel temperature control (optional at order placement), typically managing pre-heating, longitudinal sealing, and dual transverse sealing/cutting mechanisms. Special PID algorithms address thermal inertia and lag inherent in heating elements and metal conductivity. This ensures precise ±1℃ temperature control without overshooting, matching the performance of dedicated temperature controllers while accelerating heating processes.
If the control system represents the "brain" of the packaging machine, the servo motors and drivers serve as the "executive mechanisms." Film feeding stability, rapid response, and smooth transverse sealing knife operation depend on both precise controller instructions and the servo system's accuracy, stability, and dynamic response during speed changes. HollySys' "SenChuang" AC servo motors, featuring high torque output, precise positioning, overload capacity, and low-noise operation, have achieved zero repair rates over three years of field use, proving their reliability and industry compatibility.
In summary, HollySys Motor Technology's pillow-type packaging controllers combine powerful performance, advanced algorithms, flexible configurations, and compatibility with single/dual servo machines from various manufacturers. Paired with their proven SenChuang AC servo systems, these solutions offer unmatched system integration advantages, exceptional cost-performance ratios, and maximized customer value.
