Waveform display device provided with search function according to set condition

A machine tool, comprising:

• a numerical control device;
• a servo motor controlled by the numerical control device;
• and
• a waveform display device displaying, by a waveform, a time series of physical quantity data changing with time in the machine tool,
• the waveform display device comprising:
• a time series data acquisition part coupled to the numerical control device of the machine tool, and acquiring the time series of physical quantity data from the numerical control device;
• a search condition setting part setting a search condition of the physical quantity data;
• a data search part searching for physical quantity data satisfying the search condition set by the search condition setting part, from among the physical quantity data acquired by the time series data acquisition part;
• and
• a search result display part extracting a time series of physical quantity data in a predetermined range including the physical quantity data searched by the data search part or other physical quantity data corresponding to the physical quantity data searched by the data search part, from among the physical quantity data acquired by the time series data acquisition part, and displaying the extracted time series of physical quantity data by a waveform,
• wherein, when a plurality of the physical quantity data satisfying the search condition are searched by the data search part, the search result display part successively displays by waveforms a plurality of time series of physical quantity data in a predetermined range including the respective searched physical quantity data or other physical quantity data corresponding to the respective searched physical quantity data, to enable monitoring of an operation state of the machine tool.