Method for predicting remaining life of numerical control machine tool

A method for managing a tool of a computer numerical control machine, wherein

• a prediction model for a remaining life of the tool is established based on state monitoring, data de-noising, feature extraction and a multi-kernel weighted least squares support vector machine algorithm, and a prediction object for the remaining life of the tool is determined as a milling tool which is a core production element of the CNC machine, and
• the method comprises the following steps:
• step S1:
• collecting a signal from a PLC controller of the computer numerical control machine and a signal from an external sensor, and monitoring an operation condition and sensor data of the computer numerical control machine in a processing process to online monitor wear of the tool and predict the remaining life of the tool, wherein the sensor data comprises vibration signals in three directions of x-axis, y-axis and z-axis and a current signal;
• step S2:
• receiving, by a processor, original signal data, and performing pre-processing, by the processor, on the original signal data;
• step S3:
• extracting, by the processor, temporal features of the pre-processed signal obtained in step S2;
• step S4:
• obtaining, by the processor, a data matrix by using a T2 feature map of a principal component analysis PCA based on the temporal features extracted in step S3;
• step S5:
• obtaining, by the processor, a median and a variation of an eigenvector in the data matrix obtained in step S4 in a time period, a first-order difference of the median, and a first-order difference of the variation;
• step S6:
• inputting, by the processor, the matrix eigenvector obtained in step S5 to the multi-kernel weighted least squares support vector machine to output a remaining life value of the tool of the computer numerical control machine;
• and
• step S7:
• replacing the tool of the computer numerical control machine in a case that the outputted remaining life value of the tool is less than a predetermined life threshold.