Method for monitoring a production process, method for indirectly deducing a systematic dependency, method for adapting quality, method for starting a production process, method for producing an extrusion product and system for producing an extrusion product

A method for monitoring a production process for an extrusion product by means of a production facility, the method comprising:

• measuring a current value of a process variable of the production process with a sensor;
• comparing the measured process value to a predefined desired process value;
• determining an actual value of a setting parameter of the production facility from a production of the extrusion product;
• and
• comparing the determined actual value of the setting parameter to a predefined desired value of the setting parameter,
• wherein a deviation of the determined actual value of the setting parameter from the desired value of the setting parameter and/or of the measured process value from the desired process value is indicated, and
• wherein by means of existing comparative data for an extrusion product defined by requirements on at least one property of the extrusion product performing a sensitivity analysis by:
• receiving a fingerprint that represents a combination of actual values of setting parameters and process variables recorded during production of the extrusion product;
• analyzing the fingerprint to identify normal operating ranges for the setting parameters and process variables that yield acceptable product properties;
• establishing warning ranges and alarm ranges around the normal operating ranges, wherein the warning range is larger than the normal range and the alarm range is larger than the warning range;
• evaluating Pareto fronts between individual influencing values to determine how the individual influencing values condition and interact with one another while simultaneously optimizing multiple quality criteria;
• and
• determining correlations between deviations from the normal operating ranges and resulting changes in product properties, and the actual values of the setting parameters, the measured process value, a property value, or a desired value of the setting parameter is stored in a data processing and evaluation unit or a database, and
• determining the sensitivity of the production process to a desired fingerprint and the current value of the fingerprint, and proactively intervening in the production process based on the determined sensitivity and the current value of the fingerprint by adapting process parameters when measured values deviate from the normal range but remain within the warning range to enable timely operator action that returns the process to the normal range before measured values enter the alarm range, wherein the adaptation is based on both (i) the determined correlations between range deviations and property changes and (ii) analysis of the Pareto fronts that quantifies interdependencies between variables while maintaining multiple quality criteria within specified ranges.