Patent ID: 7305313

Claim:
A quality variation display device displaying variation in a prescribed quality in a plurality of products manufactured by a manufacturing unit, comprising: a quality data storing portion that stores the measurement result of each of the products measured at a measuring unit in association with the manufacturing order; graph producing means for shifting an interval by a prescribed shift number of products, said interval corresponding to a prescribed number of products consecutive in the manufacturing order, obtaining a statistic for each of the intervals, thereby producing a graph in which the statistics are displayed at equal intervals in the manufacturing order; a display portion that displays the graph produced by said graph producing means; time information adding means for producing a measuring time axis based on said measuring time stored by said quality data storing portion and adding the measuring time axis to the graph produced by said graph producing means, wherein said measuring unit measures said prescribed quality in the manufacturing order, and said quality data storing means stores said measurement result in association with its measuring time; a manufacturing data storing portion that stores manufacturing data having production condition information indicating a change in a production condition in said manufacturing unit and the occurrence time of the change in the production condition in association with each other or manufacturing data having operation content information indicating the content of operation at said manufacturing unit and the occurrence time of the operation in association with each other; a required time storing portion that previously stores time required from the point of manufacturing at the manufacturing unit to the point of measuring at a measuring unit; and manufacturing data adding means for obtaining adjusted time produced by adding said required time stored by said required time storing portion to the occurrence time in said manufacturing data, and adding the production condition information or the operation content information to said graph based on the adjusted time and said measuring time axis.