Apparatus for detecting or predicting tool breakage
AssigneeFanuc Corporation
InventorsSusumu Maekawa, Kuniharu Yasugi
Life of this patent
Estimating the term…
Abstract
If a tool breakage occurs, a cutting time T and a maximum value (absolute value) G of a slope of a drop in a cutting load become small. A cutting load integrated value S increases as a tool wears and becomes small when the breakage occurs. Therefore, these values T, G, and S are obtained in a machining cycle, moving variable thresholds are obtained (updated) based on values T, G, and S obtained in a preceding machining cycle, and the thresholds and the values T, G, and S obtained in the current machining cycle are compared with each other to thereby determine an abnormal condition of the tool.
Claims23
An apparatus for detecting or predicting a breakage of a tool used in a machine tool, the apparatus comprising:
- cutting load detecting means for detecting a cutting load;
- means for obtaining at least one of three cutting load data by said cutting load detecting means, including a cutting time, an area of a cutting load waveform during cutting, and a maximum absolute value of a slope of a drop in a cutting load during the cutting, in a machining cycle, as a load state value in a current machining cycle;
- means for updating and obtaining a moving variable threshold based on the load state value calculated in a machining cycle before the current machining cycle;
- and
- means for comparing the load state value in the current machining cycle with the moving variable threshold to determine an abnormal condition of the tool.
An apparatus for detecting or predicting a breakage of a tool used in a machine tool, the apparatus comprising:
- cutting load detecting means for detecting a cutting load;
- means for obtaining at least one of three cutting load data by said cutting load detecting means, including a cutting time, an area of a cutting load waveform during cutting, and a maximum absolute value of a slope of a drop in a cutting load during the cutting, in a machining cycle, as a load state value in a current machining cycle;
- means for updating and obtaining a moving variable threshold based on the load state value calculated in a machining cycle for a preceding workpiece at the machining position which corresponds to the machining position in the current machining cycle;
- and
- means for comparing the load state value in the current machining cycle with the moving variable threshold to determine an abnormal condition of the tool.
A method to determine a condition of a tool used in a machine tool, comprising:
- obtaining a load state value during a current machining cycle;
- updating a moving variable threshold based on a prior load state value calculated in a machining cycle before the current machining cycle;
- comparing the load state value of the current machining cycle with the moving variable threshold, the load state value including at least one of a cutting time, an area of a cutting load waveform during cutting, and a maximum absolute value of a slope of a drop in a cutting load during the cutting;
- and
- determing a condition of the tool based on the result of the comparison and outputting the result of the determination.
Dependencies are inferred from the claim text.