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DE-112021004777-B4 - TOOL DAMAGE DETECTION DEVICE AND COMPUTER-READABLE STORAGE MEDIUM

DE112021004777B4DE 112021004777 B4DE112021004777 B4DE 112021004777B4DE-112021004777-B4

Abstract

Tool damage detection device (2), comprising a data acquisition unit (222) that acquires, for a period of time of a cutting feed, load data indicating a load on a spindle, rotational speed data indicating a rotational speed of the spindle, and coordinate value data indicating a coordinate value of a cutting point; an extraction unit (223) which extracts evaluation data from the load data based on the rotational speed data, which are to be used for evaluating the occurrence of damage to a tool, wherein the extraction unit (223) determines a type of machining performed by the tool based on the rotational speed data and the coordinate value data, and extracts the evaluation data according to the determined type of machining; a detection unit (225) which, using the evaluation data, detects the occurrence of damage to the tool; and an output unit (226) that outputs data indicating the occurrence of damage to the tool when the detection unit (225) has detected damage to the tool.

Inventors

  • Mamoru Kubo

Assignees

  • FANUC CORPORATION

Dates

Publication Date
20260513
Application Date
20211122
Priority Date
20201125

Claims (9)

  1. Tool damage detection device (2) comprising a data acquisition unit (222) which is for a period of time The system comprises: load data (specifying the load on a spindle), rotational speed data (specifying the spindle's rotational speed), and coordinate value data (specifying the coordinate value of a cutting point); an extraction unit (223) that extracts evaluation data from the load data based on the rotational speed data, which is to be used for evaluating the occurrence of tool damage, wherein the extraction unit (223) determines a type of machining performed by the tool based on the rotational speed data and the coordinate value data, and extracts the evaluation data according to the determined type of machining; a detection unit (225) that detects the occurrence of tool damage using the evaluation data; and an output unit (226) that outputs data indicating the occurrence of tool damage when the detection unit (225) has detected tool damage.
  2. Tool damage detection device (2) comprising: a data acquisition unit (222) that acquires, for a period of one cutting feed, load data indicating a load on a spindle, rotational speed data indicating a rotational speed of the spindle, and coordinate value data indicating a coordinate value of a cutting point; an extraction unit (223) that extracts evaluation data from the load data, based on the coordinate value data and the rotational speed data, which is to be used for evaluating the occurrence of tool damage; a detection unit (225) that detects the occurrence of tool damage using the evaluation data; and an output unit (226) that outputs data indicating the occurrence of tool damage when the detection unit (225) has detected tool damage.
  3. Tool damage detection device (2) according to one of the Claims 1 or 2 , where the evaluation data are the load data in a section of the cutting feed time period in which the spindle is rotating forward and the spindle speed is constant.
  4. Tool damage detection device (2) according to Claim 1 , wherein the extraction unit (223) determines that the machining operation is a tapping operation, extracts the load data as evaluation data in a section of the feed time period in which the spindle is rotating forward and the spindle speed is constant.
  5. Tool damage detection device (2) according to one of the Claims 1 until 4 , wherein the extraction unit (223) further extracts reference load data from the load data, which serve as a reference for the detection of damage to the tool, and the detection unit (225) detects the occurrence of damage to the tool based on the reference load data and the evaluation data.
  6. Tool damage detection device (2) according to Claim 5 , wherein the detection unit (225) detects the occurrence of damage to the tool based on at least one of a maximum value, a minimum value and an average value of the reference load data and at least one of a maximum value, a minimum value and an average value of the evaluation data.
  7. Tool damage detection device (2) according to Claim 6 , wherein the detection unit (225) calculates at least one threshold value from at least one of the maximum, minimum and average values of the reference load data and compares the calculated at least one threshold value with at least one of the maximum, minimum and average values of the evaluation data to detect the occurrence of damage to the tool.
  8. A computer-readable storage medium that stores a command causing a computer to obtain, for a period of one cutting feed, load data specifying the load on a spindle and rotational speed data specifying the spindle's rotational speed; coordinate value data specifying the coordinate value of a cutting point; to extract, from the load data and based on the rotational speed data, evaluation data to be used for assessing the occurrence of tool damage, whereby, based on the rotational speed data and the coordinate value data, a type of machining performed by the tool is determined, and the evaluation data are extracted according to the determined type of machining; using the evaluation data, the occurrence to detect damage to the tool; and to output data indicating the occurrence of damage to the tool when damage to the tool has been detected.
  9. A computer-readable storage medium that stores a command causing a computer to: obtain load data, indicating the load on a spindle, and rotational speed data, indicating the spindle's rotational speed, for a period of one cutting feed; obtain coordinate value data, indicating the coordinate value of a cutting point; extract evaluation data from the load data, based on the coordinate value data and the rotational speed data, to be used for evaluating the occurrence of tool damage; detect the occurrence of tool damage using the evaluation data; and output data indicating the occurrence of tool damage when tool damage has been detected.

Description

Technical field The present invention relates to a tool damage detection device and a computer-readable storage medium. General state of the art In a conventional machine tool, tool damage detection is performed. When tool damage detection is carried out, time series data, indicating the load exerted on a spindle, are acquired for a period from the start to the cessation of the tool's rotation. This acquired time series data is then compared with reference time series data, and tool damage is detected (see, for example, patent literature example 1). JP S60 - 127 957 A describes a method for detecting damage to a tool by recording fluctuations in the rotational speed of the output shaft of a motor that, for example, drives an electric twist drill. Bibliography Patent literature Patent literature example 1: JP S52 - 95 386 A Brief description of the invention Technical problem However, as in the case of tapping, for example, the load data obtained from the beginning to the end of the machining cycle may include data that occur during a strong change in load due to the acceleration/deceleration torque, and data that indicate the load during a period when no cutting is taking place. In this case, the obtained load data does not accurately represent the load exerted on the spindle during the actual machining operation performed by the tool. Therefore, when tool damage is detected using such load data, there is a possibility that the damage will not be accurately detected. An object of the present invention is to reliably detect damage to a tool by accurately recording the characteristics of the load exerted on a spindle. This object is achieved by a tool damage detection device according to claim 1 or 2, or by a computer-readable storage medium according to claim 8 or 9. Solution to the problem A tool damage detection device comprises a data acquisition unit that acquires load data, indicating the load on a spindle, and rotational speed data, indicating the spindle's rotational speed, over a period of one cutting feed; an extraction unit that extracts evaluation data from the load data based on the rotational speed data, which is to be used for evaluating the occurrence of tool damage; a detection unit that detects the occurrence of tool damage using the evaluation data; and an output unit that outputs data indicating the occurrence of tool damage when the detection unit has detected tool damage. A computer-readable storage medium stores an instruction that causes a computer to obtain, for a period of one cutting feed, load data indicating the load on a spindle and rotational speed data indicating the rotational speed of the spindle; to extract evaluation data from the load data based on the rotational speed data, which is to be used to evaluate the occurrence of damage to a tool; to detect the occurrence of damage to the tool using the evaluation data; and to output data indicating the occurrence of damage to the tool when damage to the tool has been detected. Advantageous effects of the invention According to the present invention, damage to the tool can be reliably detected by accurately recording the characteristics of the load exerted on the spindle. Brief description of the drawings 1 is a diagram that shows an example of the hardware setup of a machine tool.2 is a block diagram that shows an example of functions of a numerical control system.3 is a diagram that shows an example of the respective data obtained by a data acquisition unit at the time of a thread drilling operation.4 is a diagram that shows an example of the respective data obtained by the data acquisition unit at the time of a milling operation.5 is a diagram that shows an example of the respective data obtained by the data acquisition unit at the time of a drilling operation.6 is a flowchart that shows an example of a processing flow that is executed in a numerical control system.7 is a flowchart that shows an example of a processing flow that is executed in numerical control. Description of embodiments An embodiment of the present invention will be described below with reference to the drawings. It should be noted that not all combinations of features described in the following embodiments are necessarily required to solve the problem. Furthermore, descriptions exceeding what is necessary are omitted in some cases. Moreover, the following description of the embodiments and the drawings are provided to enable those skilled in the art to fully understand the present invention and are not intended to limit the scope of the claims. A tool damage detection device is a device that detects damage to a tool during or after the operation of a machine tool. Tool damage includes, for example, breakage or other damage to the tool. The tool damage detection device is, for example, a numerical control system of a machine tool. The tool damage detection device can also be a computer, such as a management server, that monitors the operating status of the