Tool abnormality determination system

1. A tool abnormality determination system which monitors a tool that machines a workpiece comprising:

a controller configured to

determine a monitoring range,

store the monitoring range, and

compare the monitoring range to a load of the tool during machining; and

an interface that notifies, when the load of the tool exceeds the monitoring range, an operator of a question regarding whether or not the tool is in an abnormal condition other than abrasion,

wherein the load of the tool is at least one of a load of a first actuator which moves the tool and a load of a second actuator which moves the workpiece,

wherein one machining operation on the single workpiece is set to one cycle, and

the controller is configured to determine the monitoring range by:

a sampling step of sampling load data regarding the load of the workpiece of the cycle in a state where the interface does not notify the operator of the question;

a peak hold step of acquiring a low-load-side peak hold value and a high-load-side peak hold value based on the sampled load data; and

a monitoring range setting step of setting a lower limit threshold value, which is obtained by correcting the low-load-side peak hold value downward using an offset amount, and an upper limit threshold value, which is obtained by correcting the high-load-side peak hold value upward using the offset amount, and setting a distance between the lower limit threshold value and the upper limit threshold value to the monitoring range, and

wherein the interface includes an abnormality button for an input indicating that the tool is in the abnormal condition and a normality button for an input indicating that the tool is not in the abnormal condition,

the controller being responsive to operation of the abnormality button in response to the question so as not to update the monitoring range, and

the controller being responsive to operation of the normality button in response to the question to update the monitoring range.

2. The tool abnormality determination system according to claim 1 ,

wherein the abnormal condition is at least one of the chipping of the tool, the non-mounting of the tool, and the jamming of chips of the workpiece.

3. The tool abnormality determination system according to claim 1 ,

wherein the sampling step, the peak hold step, and the monitoring range setting step can be repeatedly executed in this order N times, N being a natural number of 2 or more.

4. The tool abnormality determination system according to claim 1 ,

wherein after the sampling step and the peak hold step are repeated in this order N times, N being a natural number of 2 or more, the monitoring range setting step can be executed.

5. The tool abnormality determination system according to claim 1 ,

wherein after the sampling step is repeated N times, N being a natural number of 2 or more, the peak hold step and the monitoring range setting step can be executed.

6. The tool abnormality determination system according to claim 1 ,

wherein the offset amount is a value relative to the distance between the low-load-side peak hold value and the high-load-side peak hold value.

7. The tool abnormality determination system according to claim 1 ,

wherein the interface includes a cause input portion,

the load data of the first cycle is set to reference data, and

when the load data of the second or subsequent cycle exceeds an instruction lower limit threshold value which is disposed below the reference data or an instruction upper limit threshold value which is disposed above the reference data in the sampling step, a cause for the excess is input to the cause input portion by the operator.

8. The tool abnormality determination system according to claim 1 ,

wherein the abnormal condition includes a main abnormal condition which is an update target of the monitoring range and a sub abnormal condition which is not an update target of the monitoring range,

the abnormality button includes a main abnormality button for an input indicating that the tool is in the main abnormal condition and a sub abnormality button for an input indicating that the tool is in the sub abnormal condition,

the controller responsive to operation of the main abnormality button or the sub abnormality button in response to the question so as to not update the monitoring range, and

the controller responsive to operation of the normality button in response to the question to update the monitoring range.

9. The tool abnormality determination system according to claim 1 ,

wherein the controller is configured to execute a monitoring period setting step of setting a monitoring period in which whether or not the load of the tool exceeds the monitoring range is monitored.

10. The tool abnormality determination system according to claim 1 ,

wherein the controller is configured to execute a continuous excess number, which is the number of times at which the load of the tool continuously exceeds the monitoring range, to a continuous excess number threshold value, and

when the continuous excess number exceeds the continuous excess number threshold value, the interface outputs a notification of a question regarding whether or not the tool is in an abnormal condition other than abrasion.

11. The tool abnormality determination system according to claim 1 ,

wherein the tool is a lathe including a chuck device which holds the workpiece, a table to which the chuck device is fixed and which rotates around an axis, a cutting tool attached to tool table, and a slide portion which moves the tool table and the cutting tool.