Graph generating method

Abstract

To provide a graph generating method for generating a graph suitable for analyzing factors of processing failure.SOLUTION: A graph generating method obtains a physical quantity relating to the drive of a processing tool and the coordinate position of the processing tool during the execution of a machining process according to a processing program entered into a machine tool, and generates a graph using the physical quantity for a first axis and the coordinate position for a second axis.SELECTED DRAWING: Figure 3

Description

[Technical field]

[0001] The present invention relates to a graph generation method. [Background technology]

[0002] There is a technology that measures the physical quantities of a machining tool installed on a machine tool during a machining process, generates a graph with the physical quantities on the vertical axis and time on the horizontal axis, and displays multiple such graphs on a display by overlaying them on top of each other (Patent Document 1). [Prior art documents] [Patent documents]

[0003] [Patent Document 1] JP 2021-117847 A Summary of the Invention [Problem to be solved by the invention]

[0004] For example, it is conceivable to analyze the cause of a machining defect by superimposing a graph in a case where a machining defect occurs and a graph in a case where a machining defect does not occur and comparing the two graphs. However, in order to perform such a comparison, it is necessary to adjust the time axes of both graphs so that they coincide with each other. For example, if the time required for one machining process from the start to the end of machining of a specified workpiece varies, such adjustment to match the time axes becomes complicated. Thus, the above graph is not suitable for analyzing the cause of a machining defect.

[0005] SUMMARY OF THE PRESENT DISCLOSURE An object of the present invention is to provide a graph generating method for generating a graph suitable for analyzing the causes of machining defects. [Means for solving the problem]

[0006] The above object can be achieved by a graph generation method, which acquires physical quantities related to the drive of a machining tool and the coordinate position of the machining tool during a machining process according to a machining program inputted into a machine tool, and generates a graph with the physical quantities as a first axis and the coordinate position as a second axis. Effect of the Invention

[0007] According to the present invention, it is possible to provide a graph generating method for generating a graph suitable for analyzing the causes of machining defects. [Brief description of the drawings]

[0008] [Figure 1] FIG. 1 is a schematic diagram of a machine tool. [Diagram 2] 1 is a flowchart illustrating an analysis method. [Diagram 3] FIG. 13 is an example of a case where Z-coordinate axis graphs showing when a defect occurs and when normal are overlapped and displayed on a display. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0009] FIG. 1 is a schematic diagram of a machine tool 1. The machine tool 1 is, for example, a machining center. The machine tool 1 includes a spindle 10, a machining tool 12, an X-axis actuator 20, a Y-axis actuator 21, a Z-axis actuator 22, a rotary actuator 23, a sensor group 30, a controller 50, and a display 51. The machining tool 12 is attached to the tip of the spindle 10. The machining tool 12 extends along the Z-axis direction. The machining tool 12 is, for example, a cutting tool such as a milling cutter. Examples of the machining of the workpiece W by the machining tool 12 include cutting, grinding, finishing (polishing), drilling, and deburring.

[0010] The X-axis actuator 20, the Y-axis actuator 21, and the Z-axis actuator 22 move the machining tool 12 together with the spindle 10 in the X-axis, Y-axis, and Z-axis directions, respectively. The rotation actuator 23 rotates the machining tool 12 around a central axis extending along the Z-axis direction of the machining tool 12. The X-axis, Y-axis, and Z-axis directions are perpendicular to each other. The Z-axis direction is parallel to the vertical direction. The X-axis and Y-axis directions are both horizontal.

[0011] The sensor group 30 is composed of a plurality of sensors. Specifically, the sensor group 30 includes a sensor for detecting each torque of the X-axis actuator 20, the Y-axis actuator 21, the Z-axis actuator 22, and the rotary actuator 23, a sensor for detecting a power value to the rotary actuator 23, and a sensor for detecting a Z coordinate position of the machining tool 12. The torques of the X-axis actuator 20, the Y-axis actuator 21, the Z-axis actuator 22, and the rotary actuator 23 correspond to an X-axis torque, a Y-axis torque, a Z-axis torque, and a rotation torque that move the machining tool 12 in the X-axis direction, the Y-axis direction, the Z-axis direction, and the rotation direction, respectively. These torques and power values ​​are examples of physical quantities related to the driving of the machining tool 12.

[0012] The controller 50 is electrically connected to the X-axis actuator 20, the Y-axis actuator 21, the Z-axis actuator 22, the rotary actuator 23, and the sensor group 30. The controller 50 includes a central processing unit (CPU), a read only memory (ROM), a random access memory (RAM), and a hard disk drive (HDD). The controller 50 controls the X-axis actuator 20, the Y-axis actuator 21, the Z-axis actuator 22, and the rotary actuator 23 based on measurement data from the sensor group 30 and information previously stored in the ROM in accordance with a numerical control (NC) program previously stored in the HDD. In this way, the controller 50 controls the X-axis torque, the Y-axis torque, the Z-axis torque, and the rotary torque of the machining tool 12 and the position of the machining tool 12 to machine the workpiece W. In addition, the controller 50 displays a graph on the display 51, which will be described in detail later. The controller 50 analyzes the cause of the machining defect of the workpiece W by the following method.

[0013] 2 is a flow chart illustrating a method for analyzing the causes of machining defects. While the machine tool 1 is performing a machining process on the workpiece W, the controller 50 acquires and stores measurement data from the sensor group 30 (step S1). Here, the measurement data includes physical quantities such as the rotational torque described above and the Z coordinate position of the machining tool 12. The measurement data is stored in, for example, a CSV (Comma Separated Value) format.

[0014] Next, the controller 50 generates a time axis graph based on the measurement data, with the vertical axis representing the physical quantity of the machining tool 12 and the horizontal axis representing time, and displays the graph on the display 51 (step S2). For example, the controller 50 generates a plurality of time axis graphs, with the vertical axis representing X-axis torque, Y-axis torque, Z-axis torque, rotational torque, and power value, respectively. The worker can identify the time when the machining defect occurred based on such a time axis graph. The worker operates the controller 50 to identify the area around the location where the machining defect occurred on the time axis graph.

[0015] The controller 50 extracts the measurement data of the defect location specified by the operator (step S3). Next, the controller 50 generates a Z-coordinate axis graph, in which the vertical axis represents the physical quantity of the machining tool 12 and the horizontal axis represents the Z-coordinate of the machining tool 12, based on the extracted measurement data, and displays the graph on the display 51 (step S4). Specifically, the controller 50 displays the measurement data when the defect occurred and the measurement data when normal that has been stored in advance, superimposed on each other, on the display 51.

[0016] FIG. 3 is an example of a case where Z-coordinate graphs showing when a defect occurs and when the system is normal are superimposed and displayed on the display 51. In the example of FIG. 3, there is no significant difference in the power value, rotational torque, and Z-axis torque between when a defect occurs and when the system is normal. However, there is a significant difference in the X-axis torque and Y-axis torque between when a defect occurs and when the system is normal. In this way, it is easy to grasp the physical quantity that has a large difference between when a defect occurs and when the system is normal at the Z-coordinate position. In addition, the horizontal axis of both graphs is the Z-coordinate position. This makes it easy to superimpose the two graphs, making such a Z-coordinate graph a graph suitable for analyzing the causes of machining defects.

[0017] Based on such a Z coordinate axis graph, the operator inputs a threshold value for stopping the machining tool 12 to the controller 50. For example, in the example of Fig. 3, the operator inputs to the controller 50 a threshold value of the torque in the X-axis direction at a specific Z coordinate position and a threshold value of the amplitude or magnitude in the Y-axis direction.

[0018] The controller 50 sets the threshold value input by the operator (step S5). This allows the machining tool 12 to be stopped if a machining defect occurs the next time the same machining process is performed with the same machining tool 12.

[0019] In the graph shown in FIG. 3, the Z coordinate position of the machining tool 12 is taken as the horizontal axis, but this is not limited thereto. For example, the X coordinate position or the Y coordinate position of the machining tool 12 may be taken as the horizontal axis. In the graph shown in FIG. 3, the vertical axis represents the physical quantity of the machining tool 12 and the horizontal axis represents the Z coordinate position of the machining tool 12, but the vertical axis may represent the Z coordinate position and the horizontal axis may represent a physical quantity related to the driving of the machining tool 12. The physical quantity related to the driving of the machining tool 12 is not limited to the above. For example, the physical quantity may be the movement acceleration, rotation speed or rotation acceleration of the machining tool 12 in a predetermined direction, or a voltage value or current value of an actuator that drives the machining tool 12.

[0020] Although the embodiments of the present invention have been described in detail above, the present invention is not limited to such specific embodiments, and various modifications and variations are possible within the scope of the gist of the present invention described in the claims. [Explanation of symbols]

[0021] 1 Machine tools 12 Processing tools 50 Controller

Claims

[Claim 1] Acquiring physical quantities related to the drive of a machining tool and a coordinate position of the machining tool during a machining process according to a machining program inputted to a machine tool; generating a graph with the physical quantity as a first axis and the coordinate position as a second axis; Graph generation method.

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