Quality abnormality analysis method, method of manufacturing metal material, and quality abnormality analysis device

A method of manufacturing a product being a metal material manufactured through a plurality of manufacturing processes, the method comprising:

• a quality prediction step of predicting quality of the product by inputting manufacturing conditions to a quality prediction model;
• wherein the quality prediction model is a model for predicting quality of metal material manufactured through one or a plurality of processes and the quality prediction model is generated through:
• a first collection step of collecting manufacturing conditions of processes for each of predetermined ranges of the metal material;
• a second collection step of evaluating and collecting, for each of the predetermined ranges, the quality of the metal material manufactured through the processes;
• a storage step of storing manufacturing conditions of the processes and the quality of the metal material manufactured under the manufacturing conditions in correlation for each of the predetermined ranges;
• and
• a quality prediction model generation step of generating, from the stored manufacturing conditions for each of the predetermined ranges in the process, the quality prediction model for predicting the quality of each of the predetermined ranges of the metal material;
• a quality evaluation step of calculating a quality evaluation value of an actual product manufactured through the manufacturing processes;
• a quality prediction error calculation step of calculating, as a quality prediction error, a difference between a quality prediction value obtained as an output of the quality prediction step and the quality evaluation value wherein the quality prediction error indicates that a relation between the manufacturing conditions and the quality has been changed from a prior relationship;
• a quality contribution calculation step of calculating quality contribution degrees of the input manufacturing conditions when predicting the quality of the product using the quality prediction model;
• a quality abnormality cause presentation step of presenting, based on the quality prediction error and the quality contribution degrees, a manufacturing condition causing a quality abnormality of the product;
• a predicting step of predicting quality of a final product with the quality prediction model generated by a quality abnormality analysis;
• a determining step of determining a manufacturing condition of a manufacturing process based on a result of the prediction step;
• and
• an operating step of operating the plurality of manufacturing processes under the determined manufacturing condition.