Retrofitting Gives Spinning Machines New Lease on Life

Safilin, a company combining French capital with Polish expertise, manufactures flax- and hemp-based products, including yarns used in the apparel, furniture, technical textiles, food, automotive, and many other industries. The company also produces rovings for composite materials, as well as twines and twisted yarns for a variety of applications. In Poland, Safilin operates production facilities in Miłakowo and Szczytno. The latter site houses both a wet spinning mill and a combing plant. The facility produces approximately 2,000 tonnes of finished products annually. For wet spinning, it uses PM88 machines, commonly referred to as PMs. These machines have been in operation since 1982, meaning they have been running for more than 40 years. As part of its industrial strategy, the company decided to explore alternatives to its existing equipment and leverage its deep process expertise to build a competitive advantage in flax yarn production. Seeking to make the most of its existing assets, the management team launched a retrofit program aimed at giving the PM machine a second life while renaming it the PZ-KA. The decision to modernize the aging machines enabled the automation of processes and the real-time visualization of production parameters, resulting in improved operational efficiency and significant cost savings. A key success factor was the creation of a comprehensive project team, bringing together Safilin specialists from various disciplines who actively contributed to the initiative.

The flax spinning process involves drafting and simultaneously twisting a chemically treated roving, that is, a pre-processed and slightly twisted flax sliver of a specified linear density.

“At the Szczytno facility, spinning is carried out using the wet-spinning method. A roving bobbin is placed on the spinning frame, where the ‘spinning preparation’ process begins. This involves passing the roving through a water bath maintained at 18–22°C and then through a series of guides that allow it to unwind gradually and in a controlled manner,”
explains Aleksandra Kaszubowska, Process Engineer at Safilin.

The PM88 machine consisted of three main components: an electrical cabinet, a mechanical cabinet, and a working module. The mechanical cabinet was designed to transmit drive power through a system of gears, chains, and belts. In fact, the entire mechanism, comprising approximately 50 components, primarily spur gears, was driven by a single electric motor.

“This solution made it difficult to change machine parameters, as it required manual intervention, including replacing gears to alter transmission ratios. In addition, mechanical adjustment components had to be used, such as a ratchet mechanism for controlling cyclic motion. This required precise setting adjustments and prolonged the time needed to adapt the machine to a new product range,”
recalls Aneta Siemak, Supervisor of the Spinning Department.

Work on the retrofit project began in May 2023 and continued until July 2024. The entire mechanical cabinet was redesigned and adapted for the installation of servo motors. During the modernization, several components were replaced, including the gear train, which was substituted with servo-driven systems. Bearing assemblies and drive shafts were also modified to operate under the new conditions. These changes enabled precise adjustment of machine operating parameters, significantly improving overall performance.

“Thanks to the servo motors, there is no longer any need for manual intervention in the drive system, eliminating the requirement to replace gears. Machine parameters are now adjusted through the PLC controller. In addition, we have full visibility of every parameter within each working section of the machine, allowing for quick and easy reconfiguration of settings and optimization of the production process,” says Maciej Rusinek, Chief Energy Engineer at Safilin.

“We optimized the durability of key power transmission components, such as bearings, shafts, and other assemblies, which has significantly improved the reliability of the entire system,” adds Kamil Baran, Mechanical Engineer at Safilin.

The reduction in the number of mechanical components has also made maintenance easier by providing better access to critical parts, significantly reducing downtime. Altogether, these improvements have contributed to higher machine efficiency and greater operational reliability.

Electrical Control Cabinet Before Modernization.

Thanks to the retrofit, the safety of machine operation has also been significantly improved. The PZ-KA is now equipped with a new safety system designed in accordance with the requirements identified through the risk assessment process. Among other features, the machine has been fitted with standard mushroom-type emergency stop buttons.

“The safety system is supervised by a programmable safety relay from the SIRIUS 3SK2 family. In addition to the basic emergency stop function, an unlock request function has also been implemented, enabling the machine to be brought to a safe stop,” says Ewelina Radomska, Health, Safety and Environmental Specialist.

Automation is controlled by the Siemens CPU integrated into the SIMATIC S7-1500 controller, which coordinates the operation of the servo drives and other machine components. Among its functions are the synchronization of drive speeds and processes, as well as the control of solenoid valves and ventilation systems. The TP1200 Comfort HMI operator panel, in turn, manages the machine’s basic functions. It enables diagnostics of system components, including the drives, and provides control and monitoring of process parameters. The panel also visualizes key operating data, such as the fill level of the bobbin onto which the yarn is wound.

The machine modernization project included a wide range of activities related to technological integration and the implementation of new IT solutions. The primary objective of this part of the project was to create a system capable of digitally collecting production data, processing it, and analyzing it to optimize manufacturing processes.

“The data collected makes it possible to recreate a complete picture of the machine’s operation, allowing us to identify potential issues, plan corrective actions, and improve operational efficiency. More than 120 machine parameters are recorded, the most important of which include spindle speed, ring rail oscillation, feed rate, and delivery rate,” says Jan Słowiński.

“As part of the project, application servers were configured to collect live production data. Data transmission is streamlined by the Node-RED process orchestration environment, which enables the automation of data flows between different systems. Combined with the cron scheduling utility, it gives us complete flexibility in defining when and how information is transmitted. All machine data collected is stored in an SQL database,” explains Maciej Chudziński, Software Engineer at Safilin.

The final stage of the IT implementation was the development of a data visualization system in Power BI. This platform enables the creation of interactive reports and analytical dashboards that provide users with clear and dynamic insights into production performance. These visualizations support the identification of issues and facilitate data-driven decision-making.

The results achieved through the modernization of the PM88 have been so successful that the plant is planning to retrofit additional machines. According to the project assumptions, the return on investment is expected to be achieved in just over one year. Other benefits include increased operational safety and a significant improvement in working conditions, thanks to a reduction in noise levels from 94 dB to 89.5 dB. The quality of the finished product has also improved, particularly in terms of strength and yarn evenness. Owing to the implemented IT solutions, yarn quality indicators are now continuously monitored in Power BI.

The financial benefits stem primarily from lower yarn production costs, achieved through an approximately 19% increase in machine productivity. In absolute terms, average output rose from 176 kg per day to 209.5 kg per day.