The melting pressure always in view

One of these market trends is the increasing digitalization and networking of production processes as part of Industry 4.0. The goal is the smart factory. Intelligent sensors and actuators are essential for optimal data exchange between machines and successful human-to-machine communication. They are also used for machine control and synchronization as well as for monitoring production systems and ensuring machine safety.

Intelligent sensors with IO-Link

The integration of sensors into automated systems requires appropriate interfaces and communication protocols, such as the digital communication standard IO-Link, which is standardized in mechanical engineering. It enables bidirectional communication - even with components at the lowest field level. Combined with diagnostic functions and the ability to transmit various process parameters, IO-Link sensors also contribute to better system availability through preventive maintenance and optimization of product quality.

Macchi also uses these advantages - process optimization and Industry 4.0 suitability - for its extruders and integrates melt pressure transmitters with digital IO-Link output for precise recording of the melt pressure as well as magnetostrictive displacement transducers from Gefran, also equipped with IO-Link, for precise position recording of the hydraulic axes of the extrusion lines.

In line with the company's philosophy, which is geared towards sustainability and resource conservation, the choice fell on environmentally friendly, filling-media-free impact melt pressure sensors and equally ecologically harmless, sodium-potassium-filled melt pressure transducers. Both sensor types belong to the IL series, which Gefran developed specifically for the requirements of Industry 4.0 and equipped with the IO-Link communication standard.

Both the self-monitoring Impact mass pressure sensors (Impact = Innovative Melt Pressure Accurate Transductor) and the filled sensors are SIL2-certified and have an overpressure cut-off in accordance with PL d. They detect the melt pressure in the Macchi extruders with absolute precision, even at high temperatures of 350 °C (ILI) to over 500 °C (ILC), detect overpressures and automatically shut down the system in good time.

Macchi is a manufacturer of blown film extrusion lines. © Macchi

The sensor also monitors various safety-critical states, including the bridge voltage, the function of the preamplifier stage, the temperature in the amplifier housing and the supply voltage. The sensors therefore improve machine safety and system reliability in equal measure. In addition, the continuous monitoring and control of the melt pressure ensures a consistently high quality of the end product, as the geometry of the extrudate and therefore its quality is determined by the melt pressure.

In addition to the pressure signal, the sensors record temperature curves and also record the total operating hours of the sensor under pressure. This allows algorithms to be developed that ensure better productivity and a longer service life for the extruder.

Non-contact position sensors for greater precision

Macchi has replaced conventional displacement sensors in the hydraulic axes of its blown film extrusion lines with magnetostrictive displacement sensors with Hyperwave technology and digital IO-Link output from Gefran. According to the manufacturer, the contactless cULus-certified position sensors with IO-Link 1.1 are currently the only displacement sensors on the market that can provide cyclical data on cursor position and movement speed. This eliminates the need for the user to perform a calculation step to obtain this information via the controller. They are accurate in measurement and resistant to EMC interference and vibrations and can be integrated into Industry 4.0 architectures of medium-sized and large machines in various industrial sectors.

Just like the self-monitoring melt pressure sensors, the Hyperwave displacement transducers also enable preventive maintenance of the sensor and machine thanks to the precise interpretation of large amounts of information, thereby increasing process efficiency. They also enable particularly fast data exchange, as the IO-Link master reconfigures the parameters and adapts them to the sensor. Standardized IO-Link connection cables are designed to ensure simplified installation.

More than just components

But Gefran didn't just supply the digitized sensors. "The solution package for increasing the production efficiency of our extruders also included the necessary automation platforms, which give us the option of remote maintenance and remote service, as well as the integration of all components into the extrusion lines and, last but not least, comprehensive advice on the planning, development and construction of the control panels," explains Cristiano Procopio, R&D Director at Macchi. In particular, Gefran supported the R&D team in the creation of ad hoc software for the management of the production line on multiple platforms and process automation.