Abnormality determination device and machine tool

Abstract

An abnormality determination device 1 comprises: an image acquisition unit 20 that acquires image data of the inside and outside a machine tool 10; a chip determination unit 21 that determines whether a chip130 is included in an image acquired by the image acquisition unit 20; a color and shape determination unit 23 that determines at least the color or shape of a chip portion which has been determined as the chip 130 by the chip determination unit 21; a condition setting unit 30 that has a setting value necessary for abnormality determination; a condition setting acquisition unit 31 that acquires a threshold value from the condition setting unit 30; and an abnormality determination unit 32 that detects an abnormality by comparing at least color data or shape data acquired from the color and shape determination unit 23 with the threshold value acquired by the condition setting acquisition unit 31.

Description

Abnormality determination device and machine tool

[0001] The present disclosure relates to an abnormality determination device and a machine tool.

[0002] There are known devices for detecting abnormalities during machining using machine tools. For example, Patent Document 1 discloses a machining abnormality detection device that determines whether or not a machining abnormality exists based on image data acquired by an imaging device provided on the machine tool.

[0003] Japanese Patent Application Laid-Open No. 2023-113045

[0004] The problem to be solved by the present disclosure is to increase tool life. The present disclosure aims to provide an abnormality determination device and a machine tool that are capable of increasing tool life and suppressing the occurrence of machining defects due to tool damage or tool deterioration.

[0005] The abnormality determination device of the present disclosure comprises an image acquisition unit that acquires image data from inside and outside the machine tool, a chip determination unit that determines whether the image acquired from the image acquisition unit contains chips, a color and shape determination unit that determines at least one of the color and shape of the chip portion determined to be chip by the chip determination unit, a condition setting unit that has setting values ​​necessary for abnormality determination, a condition setting acquisition unit that acquires a threshold value from the condition setting unit, and an abnormality determination unit that detects abnormalities by comparing at least one of the color data and shape data acquired from the color and shape determination unit with the threshold value acquired by the condition setting acquisition unit.

[0006] According to the abnormality determination device and machine tool disclosed herein, it is possible to provide an abnormality determination device and machine tool that can increase tool life and suppress the occurrence of machining defects due to tool damage or tool deterioration.

[0007] 1 is a block diagram showing the configuration of a machine tool according to an embodiment of the present disclosure; FIG. 2 is a diagram for explaining interference colors of chips; FIG. 3 is a cross-sectional view of chips showing a flow-type chip shape; FIG. 4 is a cross-sectional view of chips showing a shear-type chip shape; FIG. 5 is a cross-sectional view of chips showing a crack-type chip shape; FIG. 6 is a cross-sectional view of chips showing a tear-type chip shape; FIG. 7 is a flow diagram showing the flow of abnormality determination and response to an abnormality; FIG. 8 is a diagram showing threshold temperatures for determining an abnormality, and responses to an abnormality; FIG. 9 is a diagram showing content of condition changes for each machining program being executed; FIG. 10 is a diagram showing stopping methods for each temperature when stopping machining; FIG. 11 is a diagram for explaining the retraction operation of a tool; FIG. 12 is a diagram showing content of condition changes for each shape of chip; FIG. 13 is a diagram showing content of condition changes for each number of turns of chip.

[0008] DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0023] The present disclosure will be described with reference to the accompanying drawings. The present disclosure is not limited to the following embodiments. The present disclosure can be appropriately modified and implemented without departing from the spirit and scope of the present disclosure.

[0009] 1 is a block diagram showing the configuration of a machine tool 10 according to an embodiment of the present disclosure. The machine tool 10 includes an abnormality determination device 1, a condition change unit 40, a warning generation unit 41, and an evacuation operation unit 42.

[0010] (Abnormality Determination Device) The abnormality determination device 1 is a device that determines whether or not there is an abnormality in machining based on at least one of the color and shape of the chips. The chips are, for example, chips that are generated when a workpiece is machined by a machine tool 10 or the like. The shape of the chips includes the shape of the chips and the number of turns of the chips. An abnormality in machining refers to, for example, a higher-than-expected rise in the temperature of the machined portion of the workpiece, or a higher-than-expected rise in the temperature of a tool used in machining.

[0011] The abnormality determination device 1 includes an image acquisition unit 20 , a chip determination unit 21 , a color and shape determination unit 23 , a temperature determination unit 24 , a condition setting unit 30 , a condition setting acquisition unit 31 , and an abnormality determination unit 32 .

[0012] (Image Acquisition Unit) Image acquisition unit 20 is a part that acquires image data inside machine tool 10 or outside machine tool 10. Image acquisition unit 20 can be configured with an imaging element such as a CCD (Charge Coupled Device), for example.

[0013] The portion from which the image acquisition unit 20 acquires an image is not particularly limited as long as it is a portion where chips are thought to exist. The portion from which the image is acquired may be the interior of the machine tool 10, the outer surface of the machine tool 10, the surface of the floor on which the machine tool 10 is installed, the surface of a wall near the machine tool 10, etc. Chips may adhere to the outer surface of the machine tool 10 and the surface of a wall near the machine tool 10. Chips may fall on the surface of the floor on which the machine tool 10 is installed.

[0014] When suction machining is being performed in machine tool 10, image acquisition unit 20 may acquire an image of the inside of a container in which sucked chips are collected. Alternatively, image acquisition unit 20 may acquire an image of the inside of a pipe that sucks chips from machine tool 10.

[0015] (Chip Determination Unit) The chip determination unit 21 is a part that determines whether chips are included in the image acquired by the image acquisition unit 20. The image acquired by the image acquisition unit 20 may contain objects other than chips. Examples of objects other than chips include the inside of a machine tool, the floor surface, the wall surface, and a container.

[0016] The method by which the chip determination unit 21 determines whether chips are contained in an image is not particularly limited. Examples of the method by which the chip determination unit 21 determines whether chips are contained in an image include the following. The chip determination unit 21 extracts, for example, feature amounts from the image acquired by the image acquisition unit 20. The feature amounts include, for example, the pixel values ​​(color, brightness, etc.) corresponding to objects in the image, the texture of the object, the color of the object, the size of the object, and the shape of the object. The chip determination unit 21 can determine whether chips are contained in the image from these feature amounts.

[0017] The chip determination unit 21 may determine whether or not chips are contained in an image using a determination model generated by machine learning such as deep learning.

[0018] (Color and Shape Determination Unit) The color and shape determination unit 23 is a unit that determines at least one of the color and shape of a chip portion in an image that has been determined to be chip by the chip determination unit 21. The color and shape determination unit 23 includes a color determination unit 231 and a shape determination unit 232.

[0019] (Color Determination Unit) The color determination unit 231 is a unit that determines the color of chips (chip portions). The color determination unit 231 can determine the color of chips using, for example, a camera or a color sensor. The color determination unit 231 outputs the determined color as color data. The color data can be in the form of, for example, numerical values ​​of reference colors such as RGB (Red, Green, Blue) or CMYK (Cyan, Magenta, Yellow, Key Plate). Alternatively, the color determination unit 231 may directly specify a color as a color name.

[0020] (Oxide Film) When the workpiece is metal, the color of the chips changes depending on the thickness of the oxide film formed on the surface of the metal chips during machining. The thickness of the oxide film formed also changes depending on the temperature during machining. This will be explained based on FIG. 2. FIG. 2 is a cross-sectional view of chips 130 to explain the interference colors of chips. The chips 130 include metal 100. When a metal workpiece is machined, an oxide film 110 is formed on the surface 101 of the metal 100 of the chips 130 due to the heat generated during machining.

[0021] (Interference Color) The color that appears due to diffuse reflection of light by the metal 100 and the oxide layer 110 is called an interference color. The thickness of the oxide layer 110 is indicated by D1. The interference color changes depending on the thickness D1 of the oxide layer 110.

[0022] When an oxide layer 110 is formed on the surface 101 of the metal 100, part of the light traveling toward the surface 101 of the metal 100 is reflected by the surface 101 of the metal 100, and part is reflected by the surface 111 of the oxide layer 110. The light reflected by the surface 101 of the metal 100 is indicated by L1. The light reflected by the surface 111 of the oxide layer 110 is indicated by L2. When the light L1 and the light L2 are in phase, the light L1 and the light L2 constructively interact, and the reflected light L3 becomes stronger. Furthermore, the constructive wavelength (color) differs depending on the thickness D1 of the oxide layer 110. Therefore, the interference color changes depending on the thickness D1 of the oxide layer 110.

[0023] On the other hand, the thickness D1 of the oxide coating 110 changes depending on the heat generated during machining. This is because the thickness D1 of the oxide coating 110 that is generated varies depending on the amount of heat. Generally, the thickness D1 of the oxide coating 110 that is generated increases as the amount of heat increases. From the above, it is possible to estimate the temperature of the processed part and the temperature of the tool by determining the interference color.

[0024] In addition, heat generated during machining is generally dissipated into the chips rather than the workpiece. Also, the heat capacity of the chips is smaller than the heat capacity of the workpiece. Therefore, interference colors tend to appear in the chips rather than the workpiece. Also, interference colors are more likely to be observed in dry machining. However, they can also be observed in wet machining. Furthermore, interference colors can be observed even when the cutting process is oscillating cutting. Furthermore, the material of the workpiece is not particularly limited, and can include non-ferrous metals such as iron, steel, and aluminum, as well as alloys.

[0025] (Shape Determination Unit) The shape determination unit 232 is a unit that determines the shape of chips (chip portions). The shape of chips includes the shape of the chips and the number of turns of the chips.

[0026] (Shape of chips) Examples of chip shapes are shown in Fig. 3A to Fig. 3D. Fig. 3A is a cross-sectional view of chips 130 showing a flow-type chip shape. Fig. 3B is a cross-sectional view of chips 130 showing a shear-type chip shape. Fig. 3C is a cross-sectional view of chips 130 showing a crack-type chip shape. Fig. 3D is a cross-sectional view of chips 130 showing a pluck-type chip shape. Figs. 3A to 3D show models of the shapes of chips 130 generated when the workpiece 120 is cut along the cutting line L10. The shape determination unit 232 can determine whether the chip 130 corresponds to, for example, a flow-type, shear-type, crack-type, or pluck-type shape.

[0027] Furthermore, the shape determination unit 232 can determine the number of turns of the chip 130 .

[0028] The shape determination unit 232 outputs the determined shape of the chip 130 and the number of turns of the chip 130 to the abnormality determination unit 32 .

[0029] (Temperature Determination Unit) The temperature determination unit 24 is a unit that determines the temperature of the workpiece from the color data output by the color determination unit 231. The relationship between color and workpiece temperature may differ depending on the material of the workpiece. The temperature determination unit 24 can determine the temperature of the workpiece by referring to a predetermined table that shows the relationship between color and workpiece temperature. The temperature determination unit 24 outputs the determined temperature to the abnormality determination unit as a temperature estimate value.

[0030] (Condition Setting Unit) The condition setting unit 30 is a unit that sets the temperature that is determined to be abnormal, the cutting speed that is changed when the temperature is determined to be abnormal, etc. The condition setting unit 30 is also a unit that sets the shape of chips that is determined to be abnormal, and the cutting speed that is changed when the shape of chips is determined to be abnormal, etc. The shape of chips includes the shape of the chips and the number of turns of the chips.

[0031] In the condition setting unit 30, in addition to changing the cutting speed, it is possible to set the response when it is determined that the temperature or the shape of the chips is abnormal, such as issuing a warning or alarm, stopping cutting, and the stopping method when cutting is stopped.

[0032] (Condition Setting Acquisition Unit) The condition setting acquisition unit 31 is a unit that acquires thresholds and the like from the condition setting unit 30. The thresholds include the temperature that is considered to be abnormal, the criteria for the type of abnormality, etc. The thresholds and the like acquired by the condition setting acquisition unit 31 are output to the abnormality determination unit 32.

[0033] Furthermore, the condition setting acquisition unit 31 may acquire details of measures to be taken when it is determined that the temperature or the shape of the chips is abnormal from the condition setting unit 30. The details of measures acquired by the condition setting acquisition unit 31 are output to the condition changing unit 40 and the warning generating unit 41, which will be described later.

[0034] (Abnormality Determination Unit) The abnormality determination unit 32 is a part that determines whether or not an abnormality has occurred by comparing the threshold value acquired from the condition setting acquisition unit 31 with the actual measurement. The abnormality determination unit 32 compares the color data output by the color determination unit 231, the temperature estimate output by the temperature determination unit 24, the shape of the chips 130 output by the shape determination unit 232, the number of turns of the chips 130, and the like with the threshold value. The abnormality determination unit 32 can detect an abnormality through this comparison.

[0035] (Machine tool 10) In addition to the abnormality determination device 1 described above, the machine tool 10 of the present disclosure includes a condition change unit 40, a warning generation unit 41, and an evacuation operation unit 42. When the abnormality determination unit 32 of the abnormality determination device 1 determines an abnormality, the condition change unit 40 and the warning generation unit 41 receive a notification to that effect. Upon receiving the notification of the abnormality, at least one of the condition change unit 40 and the warning generation unit 41 takes a predetermined action. The condition change unit 40 and the warning generation unit 41 can acquire the predetermined action from the condition setting unit 30 via the condition setting acquisition unit 31.

[0036] (Condition Changing Unit) The condition changing unit 40 is a part that changes the conditions of machining such as cutting when the abnormality determining unit 32 determines that an abnormality has occurred.

[0037] (Warning Generation Unit) The warning generation unit 41 is a unit that generates a warning or an alarm when the abnormality determination unit 32 determines that an abnormality has occurred. The warning may be a warning display or a warning signal. When an alarm is generated, machining such as cutting is stopped. The alarm may be set to be issued until machining is stopped.

[0038] (Retraction Operation Unit) The retraction operation unit 42 is a part that retracts the tool from the workpiece by a set value when the warning generation unit 41 stops machining. The set value is set by the condition setting unit 30. The retraction operation will be described later with reference to FIG. 8.

[0039] When the abnormality determination unit 32 determines that an abnormality has occurred, at least one of the condition change unit 40 and the warning generation unit 41 takes some kind of action, thereby eliminating the abnormal state and suppressing tool deterioration.

[0040] (Flow of Abnormality Determination and Response to Abnormality) The flow of abnormality determination and response to abnormality will be described with reference to Fig. 4. Fig. 4 is a flow diagram showing the flow of abnormality determination and response to abnormality. In Fig. 4 and the following description, S1 means step 1. The same applies to S2 and subsequent steps.

[0041] (S1) S1 is a step of acquiring an image. In S1, the image acquisition unit 20 acquires an image of a portion that is thought to contain chips by photographing the inside or outside of the machine.

[0042] (S2) S2 is a step of determining whether or not chips are included in the image acquired in S1. In S2, the chip determination unit 21 determines whether or not chips are included in the image by, for example, extracting feature amounts from the image data acquired from the image acquisition unit 20. The determination may be made using a determination model generated by machine learning or the like.

[0043] If the image does not contain chips, the flow ends. If the image contains chips, the flow proceeds to step S3.

[0044] (S3) S3 is a step of determining the color, shape, or number of turns of the chips. The color is determined by the color determination unit 231 included in the color and shape determination unit 23. The shape or number of turns is determined by the shape determination unit 232 included in the color and shape determination unit 23.

[0045] (S4) S4 is a step of determining the temperature with respect to the color. If the color is determined in S3, the temperature determination unit 24 determines the temperature based on the color data output from the color determination unit 231. The temperature determination can be performed using a predetermined table that defines the relationship between color and temperature.

[0046] If no determination is made regarding the color in S3, the process proceeds from S3 to S5 without passing through S4.

[0047] (S5) S5 is a step of setting conditions, particularly acquiring thresholds. In S5, the condition setting acquisition unit 31 acquires, from the condition setting unit 30, thresholds and the like to be compared when determining whether an abnormality has occurred.

[0048] (Temperature Threshold) The threshold may be set in multiple stages. An example of the temperature threshold will be described with reference to FIG. 5. For example, the temperature threshold may be set in four stages from a first abnormal temperature to a fourth abnormal temperature as shown in FIG. 5. The threshold temperature can be increased in stages, such as 300°C for the first abnormal temperature, 400°C for the second abnormal temperature, 500°C for the third abnormal temperature, and 600°C for the fourth abnormal temperature. Note that the number of stages and each threshold temperature shown in FIG. 5 are examples. The number of stages and each threshold temperature can be changed as appropriate.

[0049] (Threshold Values ​​Related to Shape) Examples of threshold values ​​related to shape will be described. As the threshold value related to shape, a threshold value related to the shape of the chip and a threshold value related to the number of turns of the chip can be set. Examples of the threshold value related to shape will be described with reference to FIGS. 9 and 10 .

[0050] (Shape-Related Thresholds) Figure 9 is a diagram showing the correspondence between chip shapes and the contents of condition changes. The shapes of chips 130 include flow type, shear type, crack type, and ripping type, as shown in Figures 3A to 3D, for example. The shape of chips changes depending on machining conditions such as the workpiece material, cutting angle, rotation speed, and cutting depth. In the example shown in Figure 9, the flow type is not considered abnormal. The shear type, crack type, and ripping type are considered abnormal.

[0051] Regarding machining accuracy, flow-type defects can generally be judged to be normal. On the other hand, shear-type, crack-type, and tear-off defects can be judged to be abnormal. Among these, tear-off defects are likely to indicate the formation of a built-up edge.

[0052] Therefore, for example, as shown in Figure 9, it is determined that there is no abnormality for the flow type, and no changes are made to the processing conditions. On the other hand, it is determined that there is an abnormality for the shear type, crack type, and tear type, and changes are made to the processing conditions. The changes to the processing conditions can be made differently for the shear type, crack type, and tear type. The changes to the processing conditions will be explained later.

[0053] (Threshold value for number of turns) FIG. 10 is a diagram showing the number of turns and the details of the condition changes. Generally, if the number of turns is less than one, the cutting tool and the processing conditions are inappropriate. The chips are small and tend to scatter. If the chips are less than one turn, the surface finish of the workpiece is often poor. On the other hand, if the number of turns is five or more, there is a possibility that the chips may become tangled, so it is preferable to review the processing conditions.

[0054] 10, if the number of turns is 1 turn or more but less than 5 turns, it is determined that there is no abnormality and the processing conditions are not changed. On the other hand, if the number of turns is less than 1 turn, or 5 turns or more or is irregular, it is determined that there is an abnormality and the processing conditions are changed.

[0055] As described above, the threshold value used for comparison when determining whether an abnormality has occurred can be set from multiple perspectives and in multiple stages.

[0056] (S6) In S6, the abnormality determination unit 32 determines whether or not there is an abnormality by comparing at least one of the color data from the color determination unit 231, the temperature estimate from the temperature determination unit 24, and the shape and number of turns data from the shape determination unit 232 with a threshold value.

[0057] If it is determined that there is no abnormality, the flow ends. If it is determined that there is an abnormality, the flow proceeds to step S7 or S8.

[0058] As described above, when the abnormality determination unit 32 determines that an abnormality has occurred, at least one of the condition change unit 40 and the warning generation unit 41 takes some kind of action to resolve the abnormal state. The relationship between the abnormal temperature and the corresponding action will be described below using the example shown in FIG. 5.

[0059] In the example shown in Fig. 5, a temperature of 300°C or higher and lower than 400°C is defined as a first abnormal temperature, a temperature of 400°C or higher and lower than 500°C is defined as a second abnormal temperature, a temperature of 500°C or higher and lower than 600°C is defined as a third abnormal temperature, and a temperature of 600°C or higher is defined as a fourth abnormal temperature.

[0060] In the example of responses shown in Figure 5, if the temperature is the first abnormal temperature, the response is a warning. If the temperature is the second abnormal temperature, the response is condition change 1. If the temperature is the third abnormal temperature, the response is condition change 2. If the temperature is the fourth abnormal temperature, the response is to stop the device due to an alarm.

[0061] Of the four responses described above, condition change 1 and condition change 2 are performed by the condition change unit 40. On the other hand, stopping due to a warning or alarm is performed by the warning generation unit 41. First, S7 performed by the condition change unit 40 will be described below.

[0062] (S7) S7 is a step of changing the processing conditions. In S7, the condition change unit 40 changes the conditions based on the content of the condition change acquired from the condition setting unit 30 via the condition setting acquisition unit 31.

[0063] (Condition Change Unit) As shown in Fig. 5, when the temperature estimated value is the second abnormal temperature, condition change 1 is performed. The contents of condition change 1 are illustrated in Fig. 6. Fig. 6 is a diagram showing the contents of the condition change. Fig. 6 also shows the difference in the contents of the condition change depending on the machining program being executed.

[0064] Assume that the first program is being executed. The content of condition change 1 when the first program is being executed is to change the machining speed to xxx m / s. Therefore, the condition change unit 40 changes the machining speed to xxx m / s. Note that this machining speed xxx m / s may be the maximum machining speed.

[0065] If the estimated temperature value is the third abnormal temperature, condition change 2 is performed. As illustrated in FIG. 6, condition change 2 is performed to change the machining speed to yyy m / s when the first program is being executed. Therefore, the condition change unit 40 changes the machining speed to yyy m / s. Note that this machining speed yyy m / s may be the maximum machining speed.

[0066] The processing speed yyy m / s is lower than the processing speed xxx m / s. The third abnormal temperature is higher than the second abnormal temperature. Therefore, the processing temperature needs to be lowered in condition change 2 than in condition change 1.

[0067] The content of the condition change may be different depending on the machining program being executed. The rotation speed and cutting depth may differ depending on the machining program. Therefore, it is preferable to determine the content of the condition change for each machining program.

[0068] 6, the content of condition change 1 when the first program is being executed is to change the machining speed to xxx m / s. On the other hand, the content of condition change 1 when the second program is being executed is to change the machining speed OVR (override: proportional change) to 70%. In other words, if the current machining speed is 100, the machining speed is to be changed to 70.

[0069] In this way, even if the abnormal temperature belongs to the same category and the condition change 1 is the same response, the content of the change in the machining conditions can be made different depending on the machining program being executed.

[0070] The above is an example of how the condition change unit 40 responds when the abnormality determination unit 32 determines that an abnormality has occurred. Next, an example of how the warning generation unit 41 responds when the abnormality determination unit 32 determines that an abnormality has occurred will be described.

[0071] (S8) S8 is a step of issuing a warning. In S8, the warning issuing unit 41 issues a warning based on the content of the response acquired from the condition setting unit 30 via the condition setting acquisition unit 31. Warnings include warnings and alarms. (Warning issuing unit) If the estimated temperature value is the first abnormal temperature, a warning is issued as shown in FIG. 5. Also, if the estimated temperature value is the fourth abnormal temperature, an alarm is issued. If the estimated temperature value is the fourth abnormal temperature, in addition to issuing an alarm, machining is stopped. These steps will be explained in order below.

[0072] (S9) S9 is a step for determining whether or not it is necessary to stop machining. In S9, the warning generation unit 41 determines whether or not it is necessary to stop machining based on the content of the response acquired from the condition setting unit 30 via the condition setting acquisition unit 31. In the example shown in Fig. 5, if the estimated temperature value is the first abnormal temperature, the second abnormal temperature, or the third abnormal temperature, machining is not stopped. On the other hand, if the estimated temperature value is the fourth abnormal temperature, machining is stopped.

[0073] If it is not necessary to stop the processing, the flow ends. On the other hand, if it is necessary to stop the processing, the flow proceeds to step S10.

[0074] (S10) S10 is a step of retracting and stopping the machining. Before explaining the retracting operation, the method of stopping will be explained.

[0075] (Stopping Method) When the estimated temperature value is 600°C or higher, the estimated temperature value is a fourth abnormal temperature, as shown in Fig. 5. In this case, the response is to stop the machining by issuing an alarm. The warning issuing unit 41 issues an alarm and stops the machining. The alarm can be set to issue until the machining is stopped.

[0076] When the warning generating unit 41 stops machining, multiple types of stopping methods can be provided. This will be explained with reference to FIG. 7. FIG. 7 is a diagram showing stopping methods for different temperatures when stopping machining. The first temperature, second temperature, and third temperature are all 600° C. or higher. The temperatures increase in the order of the first temperature, second temperature, and third temperature.

[0077] 7, when the temperature is equal to or higher than 600° C. and lower than the first temperature, the method for stopping the machining is to stop the machining after the program is executed. Stopping the machining after the program is executed means, for example, stopping the machining after the machining program is completed, i.e., after the machining is completed.

[0078] When the temperature is equal to or higher than the first temperature and lower than the second temperature, a controlled stop is performed. The controlled stop means, for example, reducing the speed while maintaining a predetermined reduction ratio and stopping the motor.

[0079] If the temperature is equal to or higher than the second temperature, the processing can be stopped immediately. An immediate stop refers to an immediate emergency stop. If the temperature is equal to or higher than the third temperature, it means that the temperature is significantly high. Therefore, it is preferable to stop the processing immediately.

[0080] The first temperature may be, for example, 600° C. or higher and lower than 700° C., the second temperature may be, for example, 700° C. or higher and lower than 800° C., and the third temperature may be, for example, 800° C. or higher.

[0081] Alternatively, the stopping method may be determined based on color instead of temperature. For example, the stopping method may be determined based on color A instead of the first temperature, color B instead of the second temperature, and color C instead of the third temperature.

[0082] As described above, by selecting an appropriate stopping method from among a plurality of types of stopping methods, it is possible to perform stopping that suppresses the load on the machine tool while suppressing deterioration of the tool.

[0083] When stopping machining as described above, a retraction operation may be performed. The retraction operation is an operation in which the tool is separated from the workpiece by a set value when stopping machining.

[0084] (Retraction Operation) In S10, the retraction operation unit 42 retracts the tool by a set value when the warning generation unit 41 issues an alarm and stops machining. The set value is set by the condition setting unit 30. The retraction operation of the tool 140 will be described with reference to FIG. 8. FIG. 8 is a diagram illustrating a simulation of the retraction of the tool 140. During the retraction operation, the tool 140 moves from a position indicated by tool 140A to a position indicated by tool 140B, as shown by arrow L20. Tool 140A indicates the tool 140 in a state in which the cutting edge 141 of the tool 140 is in contact with the cutting surface 121 of the workpiece 120. On the other hand, tool 140B indicates the tool 140 after the retraction operation. By moving from tool 140A to tool 140B, as shown by arrow L20, the cutting edge 141 of the tool 140 moves away from the cutting surface 121 of the workpiece 120.

[0085] By performing the retraction operation, when the tool 140 is stopped due to an alarm, the cutting edge 141 of the stopped tool 140 does not remain on the cutting surface 121 of the workpiece 120. Therefore, deterioration of the cutting edge 141 due to continued contact with the high-temperature cutting surface 121 of the workpiece 120 and the formation of a built-up edge can be suppressed.

[0086] The above has described the abnormality determination based on temperature or color and the corresponding response for steps S6 to S10. As mentioned above, abnormality determination can also be performed based on the shape of the chips, for example, the shape of the chips and the number of turns of the chips. Abnormality determination based on the shape of the chips will be described below with reference to Figures 9 and 10.

[0087] (Shape of chips) Fig. 9 is a diagram showing the shape of chips and the contents of the condition change. A case where the criterion for determining an abnormality in S6 is the shape of chips will be described. In the example shown in Fig. 9, if the shape of chips is a flow type, it is not determined to be abnormal. If the shape of chips is a shear type, a crack type, or a ripped type, it is determined to be abnormal.

[0088] If the shape of the chips is flow-type, do not change the conditions. If the shape of the chips is shear-type or crack-type, change the machining speed, rotation speed, or depth of cut. Alternatively, a warning may be issued to prompt a review of the machining conditions or tool. A warning may also be issued to point out problems with the material or instructions. If the shape of the chips is torn-type, a warning or an alarm may be issued to stop machining. This is because if the shape of the chips is torn-type, there is a high possibility that a built-up edge has formed.

[0089] In the example shown in Figure 9, if the shape of the chips is sheared, condition change 1 is performed. The content of condition change 1 is a change in the machining speed or rotation speed (x m / s), or the cutting depth (x mm). If the shape of the chips is cracked, condition change 2 is performed. The content of condition change 2 is a change in the machining speed or rotation speed (y m / s), or the cutting depth (y mm), or a warning. The warning may include a recommendation to review the machining conditions or the tool. If the shape of the chips is torn, condition change 3 is performed. The content of condition change 3 is an alarm stop.

[0090] If the shape of the chip is a flow type, no abnormality is determined in S6, and the flow ends.

[0091] If the shape of the chip is shear, cracked, or torn, it is determined to be abnormal in S6.

[0092] If the shape of the chip is shear or crack, the process proceeds to step S7. In the case of crack, if the content of condition change 2 is a change in the machining speed, rotation speed, or cutting depth, the process proceeds to step S7. In the case of crack, if the content of condition change 2 is a warning, the process proceeds to step S8, as will be explained later.

[0093] In S7, as explained using the example of color, the processing speed is changed based on the contents of condition change 1 or condition change 2.

[0094] If the shape of the chip is crack-shaped and the content of condition change 2 is a warning, or if the shape of the chip is a ripped chip, the process proceeds to step S8. In S8, as described above, a warning or alarm is issued, or machining is stopped, based on the content of condition change 2 or condition change 3. The warning may be a warning to prompt a review of the machining conditions or the tool.

[0095] If it is not necessary to stop the machining (condition change 2), the flow ends in S9. If it is necessary to stop the machining (condition change 3), the flow proceeds to S10. In S10, as described above, a retraction operation is performed as necessary, and the machining is stopped. When the machining is stopped, the flow ends.

[0096] (Shape of Number of Turns) With reference to FIG. 10 , a case where the number of turns is used as the criterion for determining whether an abnormality occurs in S6 will be described. FIG. 10 is a diagram showing the number of turns and the contents of condition changes. In the example shown in FIG. 10 , if the number of turns of chips is 1 turn or more but less than 5 turns, it is not determined to be abnormal. If the number of turns of chips is less than 1 turn, or 5 turns or more or is irregular, it is determined to be abnormal. Note that if the cutting being performed is oscillating cutting, it may be possible to select a flow in which no abnormality is detected in S6.

[0097] If the number of turns of the chips is 1 or more but less than 5, the flow ends at S6 and no change is made to the conditions. If the number of turns of the chips is less than 1, or 5 or more or irregular, the process proceeds from S6 to S7 or S8. In S7, the machining speed, rotation speed, or cutting depth is changed. In S8, a warning is issued.

[0098] 10, when the number of turns of chips is less than one, condition change 4 is performed. Condition change 4 is a change in the machining speed or rotation speed (x m / s) or the cutting depth (x mm).

[0099] If the number of turns of the chips is five or more or irregular, condition change 5 is performed. Condition change 5 is a warning. The warning may include reviewing the tool or processing conditions. For example, if the number of turns of the chips is five or more, there is a possibility that the chips may become tangled. Therefore, it is preferable to review the tool or processing conditions from the viewpoint of not only suppressing tool deterioration but also the viewpoint of suppressing tool deterioration.

[0100] If the number of turns of the chips is less than one turn, the process proceeds to step S7. In S7, as described above, the machining speed is changed based on the content of condition change 4. If the number of turns of the chips is five or more turns or is irregular, the process proceeds to step S8. In S8, as described above, a warning is issued based on the content of condition change 5. The warning may be a warning to prompt a review of the tool or machining conditions.

[0101] In the example shown in Figure 10, the change of conditions does not include stopping the machining. Therefore, the flow does not proceed from step S9 to step S10, and the flow ends. Note that the change of conditions based on the number of turns can also include stopping the machining due to an alarm.

[0102] If the appropriate tool or machining conditions are not selected during machining, the temperature of the machining area may rise above the expected temperature. If the temperature of the machining area rises above the expected temperature, the temperature of the tool may also rise, which may cause tool deterioration. Therefore, it is necessary to monitor the temperature of the machining area and prevent abnormal temperature increases.

[0103] If we look at the chips that are generated during machining, they produce interference colors depending on the temperature. By automatically detecting these interference colors during machining, it is possible to detect abnormal increases in temperature and stop the machine with a warning or alarm, or change the machining conditions. By detecting chips rather than the workpiece as a separate process, it is possible to avoid hindering production.

[0104] Furthermore, based on the shape of the chips or the number of turns of the chips, it is possible to determine abnormalities in machining, particularly abnormalities at the cutting edge, in the same way as when based on interference colors.

[0105] The abnormality determination device of the present disclosure can estimate the machining temperature from the color of the chips and determine the appropriateness of the machining conditions and the tool. The abnormality determination device of the present disclosure can also make similar determinations from the shape and number of turns of the chips. This allows the abnormality determination device of the present disclosure to extend the tool life. The abnormality determination device of the present disclosure can also suppress the occurrence of machining defects due to tool damage or tool deterioration. Furthermore, the abnormality determination device of the present disclosure can separate abnormality determination from the machining process. Therefore, abnormality determination can be performed without interfering with production. Furthermore, the abnormality determination device of the present disclosure can determine abnormalities from the chips during machining. Therefore, abnormality determination can be performed in real time without stopping the process.

[0106] The present disclosure is not limited to the above-described embodiments and modifications, and includes modifications and improvements within the scope of achieving the object of the present disclosure.

[0107] The following additional notes are further disclosed regarding the above embodiment.

[0108] (Supplementary Note 1) An abnormality determination device (1) comprising: an image acquisition unit (20) that acquires image data of the inside and outside of a machine tool (10); a chip determination unit (21) that determines whether chips are included in the image acquired from the image acquisition unit (20); a color and shape determination unit (23) that determines at least one of the color and shape of the chip portion determined to be chip by the chip determination unit (21); a condition setting unit (30) that has setting values ​​required for abnormality determination; a condition setting acquisition unit (31) that acquires a threshold value from the condition setting unit (30); and an abnormality determination unit (32) that detects an abnormality by comparing at least one of the color data and the shape data acquired from the color and shape determination unit (23) with the threshold value acquired by the condition setting acquisition unit (31).

[0109] (Supplementary Note 2) In the abnormality determination device (1), the shape of the chip portion includes at least one of the shape of the chip and the number of turns of the chip.

[0110] (Note 3) In the abnormality determination device (1), the condition setting acquisition unit (31) acquires a plurality of threshold values.

[0111] (Note 4) In the abnormality determination device (1), the changed machining conditions acquired by the condition setting acquisition unit (31) are determined for each of a plurality of thresholds or for each of a plurality of programs.

[0112] (Note 5) In the abnormality determination device (1), the machining stop method acquired by the condition setting acquisition unit (31) is determined for each of a plurality of threshold values.

[0113] (Supplementary Note 6) A machine tool (10) comprising at least one of the abnormality determination device (1), a condition change unit (30) that changes machining conditions to conditions set by the condition setting unit (30) when an abnormality is determined by the abnormality determination unit (32), and a warning generation unit (41) that generates at least one of a warning and an alarm when an abnormality is determined by the abnormality determination unit (32).

[0114] (Supplementary Note 7) In the machine tool (10), the warning generation unit (41) stops machining when a warning or alarm is generated.

[0115] (Note 8) The machine tool (10) includes a retraction operation unit (42) that retracts the tool (140) from the workpiece (120) by a set value set by the condition setting unit (30) when the warning generation unit (41) stops machining.

[0116] REFERENCE SIGNS LIST 1 Abnormality determination device 10 Machine tool 20 Image acquisition unit 21 Chip determination unit 23 Color and shape determination unit 231 Color determination unit 232 Shape determination unit 24 Temperature determination unit 30 Condition setting unit 31 Condition setting acquisition unit 32 Abnormality determination unit 40 Condition change unit 41 Warning generation unit 42 Evacuation operation unit 100 Metal 101 Metal surface 110 Oxide film 111 Oxide film surface 120 Workpiece 121 Cutting surface 130 Chip 140 Tool 141 Cutting edge L10 Cutting line

Claims

1. An abnormality determination device comprising: an image acquisition unit that acquires image data inside and outside a machine tool; a swarf determination unit that determines whether swarf is included in the image acquired by the image acquisition unit; a color and shape determination unit that determines at least one of the color and the shape of the swarf portion determined to be swarf by the swarf determination unit; a condition setting unit having set values necessary for abnormality determination; a condition setting acquisition unit that acquires a threshold value from the condition setting unit; and an abnormality determination unit that compares at least one of the color data and the shape data acquired from the color and shape determination unit with the threshold value acquired by the condition setting acquisition unit to detect an abnormality.

2. The abnormality determination device according to claim 1, wherein the shape of the swarf portion includes at least one of the shape of the swarf and the number of turns of the swarf.

3. The abnormality determination device according to claim 1 or 2, wherein a plurality of threshold values are acquired by the condition setting acquisition unit.

4. The abnormality determination device according to claim 1 or 2, wherein the changed processing conditions acquired by the condition setting acquisition unit are determined for each of a plurality of threshold values or for each of a plurality of programs.

5. The abnormality determination device according to claim 1 or 2, wherein the method of stopping the processing acquired by the condition setting acquisition unit is determined for each of a plurality of threshold values.

6. A machine tool comprising at least one of: the abnormality determination device according to claim 1 or 2; a condition change unit that changes the processing conditions to the conditions set by the condition setting unit when an abnormality is determined by the abnormality determination unit; and a warning generation unit that generates at least one of a warning and an alarm when an abnormality is determined by the abnormality determination unit.

7. The machine tool according to claim 6, wherein the warning generation unit stops the processing when generating a warning or an alarm.

8. The machine tool according to claim 7, further comprising a retraction operation unit that retracts the tool from the workpiece by a set value set by the condition setting unit when the warning generation unit stops the processing.

Images