How Synchronized Control Enhances Packaging Performance

In the fast-paced world of packaging, where speed and efficiency are critical, the needs for the "perfect seal" is a constant challenge. Companies packing goods, machine builders, and automation suppliers are all driven by the same goal: to ensure that products reach consumers in perfect condition, with extended shelf life and uncompromised quality. Form, Fill, and Seal (FFS) machines are at the heart of this endeavor, packing large quantities of goods, often food items, at high speed. However, achieving consistently high-quality seals, especially at the start of production or during machine transitions, presents a complex set of hurdles.

The Challenges of Sealing at Speed

Several factors can limit the speed and efficiency of FFS machines. These include product feed, packaging material feed, and seal-time. Flexible packaging materials, such as foil, are formed and sealed on the fly, often while the product is in motion. This process introduces numerous variables that can impact seal quality.

One of the primary challenges is maintaining a constant seal jaw temperature. The packaging material requires a specific temperature and pressure to create a reliable seal. However, the sealing process itself can cause temperature fluctuations in the seal jaw as the film absorbs heat. This is further complicated by external factors such as room temperature, packaging material temperature, and even the product temperature.

In many cases, the seal jaw alone must compensate for all these variables. Improperly sealed packages can lead to product spoilage, reduced shelf life, and compromised brand reputation. Moreover, the need to discard defective packages results in material waste and lost productivity.

Synchronized Solutions for Seal Quality

To address these challenges, Omron offers a comprehensive solution that integrates temperature control, seal-jaw timing, and pressure management. The core principle is to synchronize motion and temperature control, ensuring that the sealing process is precise and consistent, even during machine transitions. Two primary approaches are available:

1. PLC-based Direct Power Control (DPC): This function block is designed for use with Omron's unique 2-PID algorithm and is fully integrated into the machine controller. DPC enables temperature control to be synchronized with motion, managing the machine's full functionality.
2. Pre-Boost Function: Integrated into the NX-HTC in-panel temperature controllers, this feature anticipates temperature variations and pre-compensates for them, ensuring a stable sealing temperature from the start.

Both approaches aim to minimize temperature deviation from the setpoint, particularly during machine transitions from idle to production. By "preparing" the seal-jaw temperature for the anticipated drop and pre-compensating for it, these solutions ensure that the first pack produced has the same high-quality seal as those produced during continuous operation.

How it Works

The DPC function block operates in three key steps:

1. PID Control Loop Setup: The 2-PID temperature control algorithm is tuned to optimize the system for fast disturbance response.
2. Parameter Derivation: Parameters are derived from the PID values and data obtained from temperature trend charts or manual tests.
3. Parameter Loading: All parameters are loaded into a matrix used by the DPC function block in the controller.

The Pre-Boost function, on the other hand, requires minimal setup:

1. Calculate PID values by executing the Auto-Tuning (AT) procedure.
2. Execute auto-tuning for pre-boost (D-AT).
3. Execute the pre-boost function.

Business Benefits

The benefits of using these technologies are mainly for FFS machines such as flow wrappers, HFFS, and VFFS machines. By maintaining tight temperature control, these solutions prevent burned or poorly sealed packages, reducing waste and improving overall product quality.

The ability to precisely control temperature is also crucial when working with sensitive materials, such as laminated foils used in easy-to-open packaging or when packaging pharmaceuticals. OMRON solutions ensure optimal heat application, even when dealing with products that may cool down the film, such as wet or frozen items. Furthermore, the heat loss compensation provided by these controllers eliminates the need for larger, more energy-intensive sealing jaws. Smaller sealing jaws not only reduce energy consumption but also decrease heat inertia, allowing for faster and more responsive temperature control.