Tool abnormality determination system

A tool abnormality determination system for detecting abnormalities in a tool according to a state of the tool, by automatically and continuously performing correction of a monitoring range for detecting the abnormalities, the tool abnormality determination system comprising:

• a processor;
• a display;
• and
• at least one motor drive circuit connected to a respective at least one motor, the at least one motor drive circuit driving the at least one motor so as to process work by a tool on a workpiece, wherein
• the processor is configured to:
• set an offset amount;
• detect load data of the at least one motor at predetermined intervals;
• and
• use the load data of at least one of 1st to (M−1)th cycles to correct a monitoring range for a load on the tool in an Mth cycle (where M is an integer of 2 or more),
• the monitoring range is a difference between:
• (i) a first current value, which is an upper limit threshold at a given time in a first cycle;
• and (ii) a second current value, which is a lower limit threshold at the given time in a second cycle, the first current value and the second current value being peak current values,
• the lower limit threshold is determined by using the offset amount to correct a low load-side peak hold value, and the upper limit threshold is determined by using the offset amount to correct a high load-side peak hold value,
• processing the work on the workpiece by using the tool corresponds to a single cycle,
• the load data is an indicator of the load on the tool in the single cycle,
• the load data includes a plurality of current values,
• when a current value, of the plurality of current values, is out of the monitoring range, the processor is further configured to count a number of consecutive times the current value is out of the monitoring range,
• when the number of consecutive times does not exceed a number-of-consecutive-times threshold, the processor is further configured to continue to monitor the current value, and
• when the number of consecutive times exceeds the number-of-consecutive-times threshold, the processor is further configured to stop processing the work on the workpiece as soon as the current value is out of the monitoring range and display guidance on the display, the guidance prompting a user to confirm whether or not the tool is actually in an abnormal state.