Optimizing a yarn production process with respect to foreign materials

Device (100) for optimizing a yarn production process in which foreign materials (90) are monitored in a textile fiber formation (9), including

• at least one light source (103) for illuminating the textile fiber formation (9) with electromagnetic radiation from at least two different subranges of the electromagnetic spectrum,
• at least one sensor system (105) for detecting foreign materials (90) based on their interaction with the electromagnetic radiation, and
• an evaluation unit (107) connected to the sensor system (105) for evaluating an output signal of the sensor system (105),
• characterized in that
• the evaluation unit (107) is configured
• to assign a color class (411-414) of foreign materials (90) to each of at least two different subranges of the electromagnetic spectrum depending on the interaction of the electromagnetic radiation in the respective subrange of the electromagnetic spectrum with the foreign materials (90),
• to classify the detected foreign materials (90) in the at least two color classes (411-414) depending on their interaction with the electromagnetic radiation in the relevant subrange of the electromagnetic spectrum,
• when a sample having a plurality of classified foreign materials (90) is available, to determine a frequency distribution (511-514) of the foreign materials for the color classes,
• to compare the determined frequency distribution (511-514) with a reference frequency distribution, and
• to trigger at least one of a set of several optimization actions in case of a significant deviation of the determined frequency distribution (511-514) from the reference frequency distribution.