Automated Recycled Material Dyeing: Flexible Efficiency with OPM’s New Inline Dyeing System
At the heart of the system is a precise interplay of intelligent formula management, piston metering units, and continuous color control. Liquid colors are fed directly into the extruder via up to six metering stations. These piston metering units operate with virtually no pulsation and dispense the colors precisely—regardless of pressure buildup in the system. What makes this system unique is that, instead of a fixed setting, it continuously adjusts itself to achieve precise results even when there are fluctuations in material composition.
Color control is performed using the advanced GranuTrack® system. A drawer system is used to extract granules directly from the production process and measure them in a protected area to eliminate external influences. A spectral color sensor precisely monitors the material’s color values. As soon as deviations from the target value are detected, the central control system sends correction commands to the metering stations. The system uses the CIELAB color space to fine-tune the color along the three axes—luminance (L*), red-green (a*), and blue-yellow (b*). Even the slightest color changes can be detected and corrected. An impressive feature is the CLOOPMIX®’s ability to achieve precise color results using just four base colors. These colors are calibrated so that, when combined, they enable all corrections along the color axes.
During a successful field test on a Leistritz compounding line at the sister company ROMIRA in Pinneberg, the CLOOPMIX® system demonstrated its effectiveness. Despite the natural color variations in the recycled material, the color consistency remained constant, and the system responded promptly to changes in the material. The highly accurate measurement enabled a color deviation of less than ΔE 1—proof of how precisely the interaction between liquid colors, the control system, and the dosing works.
A video of the test run, including details on the system’s setup, can be found at:
www.rowasol.de/anwendungen
The successful test run underscores the close partnership between ROWASOL and OPM Mechatronic, which have created a groundbreaking solution for the automation of recycled material compounding with the CLOOPMIX® system. The system makes it possible to process even challenging recycled materials with minimal resource consumption while maintaining consistently high color quality. Thanks to the precise interaction of liquid colors, intelligent control, and real-time color measurement, color consistency remains stable even when material properties fluctuate. This project marks another milestone in sustainable plastics processing and impressively demonstrates that efficiency, precision, and environmental protection can go hand in hand.