Tool life determination apparatus and tool life determination method for machine tool

Abstract

A tool life determination apparatus (10) for a machine tool (MT) comprises: a tool wear measurement device (11) that acquires an image by capturing an image of a cutting edge part (50) of a tool (26) inside the machine tool (MT), and measures a tool wear amount indicating the amount of change in the diameter of the tool or the wear width of a flank or a rake face; a tool life index measurement unit (64) that measures, as a tool life index, at least one of the number of machined workpieces, machining distance, machining time, and machining workload which are acquired when workpieces have been machined on the basis of a machining program and machining conditions; a storage unit (66) that sequentially stores a set of the tool wear amount and the tool life index; and a calculation unit (70) that calculates a threshold for the tool life index by using the set of the tool wear amount and the tool life index and an inputted threshold for the tool wear amount.

Description

Tool life determination device and tool life determination method for machine tools

[0001] The present invention relates to a tool life determination device and a tool life determination method for machine tools.

[0002] In factories that mass-produce parts by machining them using machine tools, managing the lifespan of the tools used for machining is a crucial factor that directly impacts production costs. Replacing tools with new ones before they reach the end of their lifespan unnecessarily increases costs, and continuing to use tools beyond their lifespan can degrade the quality of the machined surface, increase cutting resistance, and potentially cause tool breakage, resulting in defective workpieces. Therefore, it is preferable to replace tools with new ones just before they reach the end of their lifespan.

[0003] To replace a tool with a new one just before it reaches the end of its lifespan, it is necessary to accurately determine when a tool has reached the end of its lifespan at the machining site. For this reason, it is common practice to sequentially and quantitatively measure the amount of wear on the cutting edge of the tool, and when the amount of wear exceeds a tool wear threshold set by the factory, a warning signal is issued to prompt tool replacement, and if the tool is not replaced, an alarm signal is issued to forcibly stop machining. Patent Document 1 discloses a tool management device that measures the flank wear width by imaging the cutting edge when the tool reaches a predetermined cutting distance (cumulative distance of cutting feed), and determines the lifespan by comparing this measured value with a standard wear width. However, there are cases where the tool wear threshold is exceeded when the predetermined cutting distance is reached, which can lead to tool breakage or workpiece defects.

[0004] On the other hand, looking around the processing site, data such as the number of machined workpieces, cutting distance, cutting time (cumulative time of cutting feed), and cutting work amount (cumulative power consumption of the spindle motor while executing cutting feed), which are considered to have a strong correlation with tool life, can be easily and constantly acquired by the control unit of the machine tool. Therefore, it is conceivable to use these as tool life evaluation indices (hereinafter referred to as tool life indices) for evaluating tool life. That is, in the processing of a workpiece using one tool, if the correlation between the tool wear amount and the tool life index can be grasped, it is possible to grasp that the tool life has been reached with the tool life index threshold without directly measuring the tool wear amount, and perform tool life management such as replacing the worn tool with a spare tool at an appropriate timing. However, tools cover a wide variety, such as end mills, face mills, drills, boring tools, turning tools, and threading tools, and their materials also vary widely, such as high-speed steel, cemented carbide, ceramics, and with or without coating. In addition to these, tools have numerous parameters such as the number of cutting edges, the difference between solid type and insert type, length, and diameter. Also, the workpieces to be processed using the tools vary widely in terms of their materials, such as cast iron, steel, aluminum, copper, titanium, etc., and their shapes, such as round objects, angular objects, and those with large variations in cutting depths. Furthermore, in addition to these, the processing conditions of the workpieces, such as rotational speed, feed rate, cutting depth, type and supply amount of cutting oil, etc., can also be parameters. Therefore, it is practically difficult to grasp in advance the correlation between the tool wear amount and the tool life index for each of these huge numbers of parameters through processing tests.

[0005] Japanese Patent Application Laid-Open No. 2002-337041

[0006] In view of the above circumstances, an object of the present invention is to provide a tool life determination device and a tool life determination method capable of automatically obtaining the relationship between a tool wear amount threshold and a tool life index threshold while actually machining a workpiece.

[0007] One aspect of the present invention is a tool life determination device for a machine tool that determines the lifespan of a tool used to process a workpiece, comprising: a tool wear amount measuring unit that captures an image of the cutting edge of the tool inside the machine tool and measures the wear width of the flank face or the rake face, or the amount of change in the tool diameter, based on the image; a tool life index measuring unit that measures at least one of the number of workpieces to be processed, the processing distance, the processing time, and the amount of work to be processed, which are acquired when a workpiece is processed based on a processing program and processing conditions input to the machine tool, as a tool life index; a storage unit that sequentially stores the measured tool wear amount and the tool life index as a pair for each tool; and a calculation unit that calculates a threshold value for the tool life index using the stored pair of tool wear amount and tool life index, and a threshold value for the input tool wear amount.

[0008] One aspect of the present invention is a tool life determination method for a machine tool using a tool life determination device for a machine tool according to one aspect of the present invention, characterized in that it includes the steps of: importing a threshold value of the tool life index calculated by a calculation unit into another machine tool; sequentially measuring the tool life index of the other machine tool; and displaying the sequentially measured tool life index and the threshold value of the imported tool life index on a display unit of the other machine tool.

[0009] One aspect of the present invention is a method for determining the tool life of a machine tool using a tool life determination device for a machine tool according to one aspect of the present invention, characterized in that it includes the steps of: importing a threshold value of the tool life index calculated by a calculation unit into another machine tool; sequentially measuring the tool life index of the other machine tool; and determining that the tool is worn when the tool life index measured sequentially in the other machine tool exceeds the threshold value of the imported tool life index, and sending a spare tool replacement command to the other machine tool to replace the worn tool with a spare tool of the same type.

[0010] According to one aspect of the present invention, a tool life determination device for a machine tool includes a tool wear amount measuring unit that measures the wear width of the flank face or rake face, or the amount of change in the tool diameter, based on an image of the cutting edge of the tool, and a tool life index measuring unit that measures at least one of the number of workpieces, machining distance, machining time, and machining work amount as a tool life index. Therefore, the correlation between the tool wear amount and the tool life index can be grasped for each tool and stored in a memory unit. Furthermore, a tool life index threshold can be calculated from the stored correlation between the tool wear amount and the tool life index and the tool wear amount threshold. Therefore, the relationship between the tool wear amount threshold and the tool life index threshold can be automatically determined while actually machining a workpiece. As a result, once the relationship between the tool wear amount threshold and the tool life index threshold for each tool used to machine a single workpiece is determined, tool life can be appropriately managed by monitoring only the tool life index without measuring the tool wear amount in subsequent machining of the same type of workpiece using the same type of tool. Furthermore, even when there are multiple workpieces to be machined, the relationship between the tool wear threshold and the tool life index threshold can be automatically determined for each tool used to machine each workpiece while the workpieces are actually being machined. Therefore, the relationship between the tool wear threshold and the tool life index threshold can be easily understood for each type of workpiece and the tool used for machining, enabling efficient tool life management for the entire machine tool.

[0011] According to a tool life determination method using a tool life determination device for a machine tool according to one aspect of the present invention, the threshold value of the tool life index calculated by the calculation unit can be imported into another machine tool, and the tool life index of the other machine tool can be measured sequentially. Therefore, when machining with the same tool and workpiece as for which the tool life index threshold was determined, without measuring the amount of tool wear, tool life can be appropriately managed by monitoring only the tool life index. Furthermore, even if the other machine tool is not equipped with a tool life determination device, tool life can be appropriately managed by monitoring only tool life indicators such as the number of workpieces to be machined, machining distance, machining time, and machining work volume. In addition, the sequentially measured tool life index and the imported tool life index threshold can be sequentially displayed on the display unit of the other machine tool. Therefore, the current value of the tool life index can be visualized and tool life can be appropriately managed in the other machine tool.

[0012] According to a tool life determination method using a tool life determination device for a machine tool according to one aspect of the present invention, the threshold value of the tool life index calculated by the calculation unit can be imported into another machine tool, and the tool life index of the other machine tool can be measured sequentially. Therefore, when machining with the same tool and workpiece as the one for which the tool life index threshold was determined, the other machine tool can appropriately manage tool life by monitoring only tool life indicators such as the number of workpieces, machining distance, machining time, and machining work volume. Furthermore, when the tool life index measured sequentially by the other machine tool exceeds the imported tool life index threshold, it can be determined that the tool is worn, and a spare tool replacement command can be sent to the other machine tool to replace the worn tool with a spare tool of the same type. Therefore, it is possible to prevent or suppress the other machine tool from continuing machining beyond the tool life index threshold, and tool life can be appropriately managed.

[0013] Figure 1 shows a block diagram of the tool life determination device according to this embodiment. Figure 2 shows a perspective view of the tool wear measuring device according to this embodiment. Figure 3(a) shows a side view of the tool, (b) shows a side view of the tool in (a) rotated 90 degrees, and (c) shows a bottom view of the tool in (a). (a) shows a side view of the first imaging unit that images the bottom of the tool, and (b) is a view from arrow A in (a), showing the bottom view of the tool. (a) shows a side view of the second imaging unit that images the side of the tool, and (b) is a view from arrow B in (a), showing the bottom view of the tool. Figure 6 shows a transparency view of the inside of the first cleaning unit. Figure 7 shows a transparency view of the inside of the first cleaning unit according to another embodiment. Figure 8 shows a transparency view of the inside of the second cleaning unit. Figure 9 shows a plan view of the tool magazine. Figure 10 shows a plan view and a side view of the tool wear measuring device according to this embodiment. Figure 11 shows a plan view and a side view of a tool wear measuring device that cleans tools using a first cleaning unit. Figure 12 shows a plan view and a side view of a tool wear measuring device that cleans tools using a second cleaning unit. Figure 13 shows a plan view and a side view of a tool wear measuring device that images the bottom of a tool using a first imaging unit. Figure 14 shows a plan view and a side view of a tool wear measuring device that images the side of a tool using a second imaging unit. Figure 15 shows an example of multiple post-machining tool images including the cutting edge. Figure 16 shows an example of detecting the maximum brightness value for each post-machining tool image. Figure 17 shows a flowchart of tool life determination according to this embodiment. Figure 18 shows a histogram of the number of tool life determinations against the amount of tool wear. Figure 19 shows a correlation diagram between the amount of tool wear and the tool life index. Figure 20 shows a database of the correlation between the amount of tool wear and the tool life index.

[0014] The tool life determination device and tool life determination method according to the embodiment will be described below with reference to the attached drawings. Similar or corresponding elements are denoted by the same reference numerals, and redundant explanations are omitted. The scale of the figures may be changed in the explanation to facilitate understanding.

[0015] Figure 1 shows a block diagram of the tool life determination device 10. The tool life determination device 10 is integrated with the machine tool body MT (machine tool) or is installed adjacent to the machine tool body MT. The tool life determination device 10 includes a tool wear measuring device 11, which is a tool wear amount measuring unit for measuring the amount of wear of the cutting edge 50 of the tool 26 used for machining, and a tool life index measuring unit 64 for measuring the tool life index. Here, the amount of tool wear of the tool 26 refers to the wear width of the flank faces 52, 54, or rake face 56, or the change in the tool diameter TR (see Figure 3), and one or more of these are used for tool life determination. The tool life index refers to the number of workpieces that the tool 26 has machined so far, the machining distance, the machining time (cumulative time of the machining performed), and the amount of machining work (cumulative power consumption of the spindle motor while machining is being performed), and one or more of these are used as the tool life index for tool life determination.

[0016] Furthermore, the tool life determination device 10 includes a storage unit 66 that stores measured tool wear amounts and tool life indices in pairs and associated manner, and a calculation unit 70 that calculates a tool life index threshold from the correlation between tool wear amounts and tool life indices and a tool wear threshold pre-input by the operator. The tool life determination device 10 also has an operation input unit 60 that receives commands from the operator to replace worn tools and inputs machining programs and machining conditions to be input to the machine tool body MT. Furthermore, the tool life determination device 10 has a machine tool control unit 62 that is electrically connected to the machine tool body MT, and commands from the operator, as well as machining programs and machining conditions input to the operation input unit 60, are transmitted to the machine tool body MT via the machine tool control unit 62.

[0017] The tool wear measuring device 11 has an imaging information storage unit 46 for storing information about the tool 26 and its imaging. The imaging information storage unit 46 has an imaging information storage unit 46a that stores information about the imaging of the tool 26, a tool information storage unit 46b that stores information about the tool 26 itself, and a tool image storage unit 46c that stores images of the tool 26 captured and acquired by the imaging device 40. Specifically, the imaging information storage unit 46a is configured to store the phase interval and time interval, which are the timings for imaging the tool 26 rotating by the rotating unit 22, and the phase range, which is the range of rotation phases for performing one set of imaging. If there are multiple blades 50 (see Figure 3) (number of blades n), reference images are acquired for the number of blades n, so multiple tool phases corresponding to each blade 50 are stored for the number of blades n. If the types of multiple blades 50 and the mounting positions and angles of each blade 50 relative to the shaft 28 (see Figure 3) are all the same, then only one reference image needs to be stored for each tool 26. The tool phase, phase interval, time interval, and phase range are set in advance by the operator and stored in the imaging information storage unit 46a. Alternatively, instead of being set by the operator, the imaging control unit 48 of the tool wear measuring device 11 may automatically set these parameters according to the information of the tool 26. The tool information storage unit 46b is configured to store the number of blades n of the blades 50 attached to the tool 26, the tool length TL of the tool 26, the blade imaging length BL, the tool diameter TR, and the blade imaging diameter BR. The tool image storage unit 46c is configured to store the reference image and the tool image after processing, which will be described later.

[0018] Furthermore, the imaging control unit 48 is configured to operate the rotating unit 22 to rotate the tool 26 and to operate the first cleaning unit 36 ​​and the second cleaning unit 38 to clean the tool 26. In addition, the imaging control unit 48 is configured to operate the imaging device 40 to image the tool 26 at the tool phase and store it as a reference image in the tool image storage unit 46c. Here, the tool phase at which the reference image is taken is determined by the operator's visual inspection, and the operator controls the imaging control unit 48 through the operation input unit 60 to position the tool 26 at the tool phase and take the image. The reference image should be taken when the tool 26 is free from defects and wear, so it is desirable to take the reference image when the tool 26 is new and has not been machined. Furthermore, the imaging control unit 48 is configured to operate the imaging device 40 to image the machined tool 26, which is rotated by the rotating unit 22, at predetermined phase intervals or predetermined time intervals, and to store the acquired multiple machined tool images in the tool image storage unit 46c.

[0019] The tool life determination device 10 includes a tool wear amount measuring unit 68 that compares a reference image stored in the tool image storage unit 46c with multiple post-machining tool images, selects the post-machining tool image with the highest degree of agreement with the reference image as the observation image, and performs image analysis on the selected observation image to measure the presence or absence of damage to the cutting edge 50 and the amount of tool wear. If the tool 26 has two or more cutting edges 50, the observation images of all cutting edges 50 may be evaluated, or only the observation image of one cutting edge 50 may be evaluated. The measured amount of tool wear is transmitted to the storage unit 66 and stored in the storage unit 66 in association with the tool life index measured by the tool life index measuring unit 64. The calculation unit 70 is configured to calculate a threshold for the tool life index from the combination of tool wear amount and tool life index stored in the storage unit 66 and the tool wear amount threshold input by the operator from the operation input unit 60.

[0020] Furthermore, the tool life determination device 10 is equipped with a display unit 72, which is configured to sequentially display the threshold value of the tool life index calculated by the calculation unit 70 and the current value of the tool life index measured by the tool life index measurement unit 64 on the same screen. The display unit 72 also has a notification function, and if the current value of the tool life index is approaching or exceeding the threshold value of the tool life index, it will issue a warning or alarm to prompt caution regarding the continuation of machining with the tool 26.

[0021] Figure 2 shows a schematic perspective view of the tool wear measuring device 11. The tool wear measuring device 11 is located adjacent to the tool magazine 30 in a location other than the machining chamber (not shown) of the machine tool body MT. However, it is not limited to this, and the tool wear measuring device may be located inside the tool magazine chamber of the machine tool body. The tool wear measuring device 11 has both a tool wear amount measuring function and a tool transport device function, and comprises a stand 12 and a tool transport device 20 as a first feed axis attached to the stand 12, as well as an imaging device 40 as an imaging unit for imaging the tool 26, and a first cleaning unit 36 ​​and a second cleaning unit 38 as cleaning units for cleaning the tool 26 before imaging (see Figure 10). The imaging device 40 has a bottom-side imaging unit 42 having a first image sensor for imaging the tool 26 from the tip side (bottom side), and a side-side imaging unit 44 having a second image sensor for imaging the side of the tool 26. Furthermore, as will be described later, the first cleaning unit 36 ​​is configured to clean the tool 26 using, for example, a cleaning solution or compressed air, and the second cleaning unit 38 is configured to dry the tool 26 after cleaning using, for example, compressed air.

[0022] The frame section 12 has four legs 14, two support columns 16 extending upward from the legs 14 along a second direction, the vertical direction D2, and a beam section 18 spanning between the two support columns 16 and extending along a first direction, the horizontal direction D1, which is perpendicular to the second direction. The tool transport device 20 is attached to the beam section 18 and is configured to be movable along the beam section 18 in the horizontal direction D1. Below the tool transport device 20, a rotating section 22 is arranged as a third feed shaft section, which has a drive unit such as a servo motor and is configured to rotate in a direction C about the axis of the tool 26 along the vertical direction relative to the tool transport device 20. The tool 26 is detachably attached to the lower side of the rotating section 22.

[0023] Figures 3(a) to 3(c) show a side view and a bottom view of the tool 26. The tool 26 has a tool holder 24 with a tapered shank portion 28a, a shaft portion 28 attached to the tool holder 24, and a cutting edge portion 50 attached to the tip side (lower end side) of the shaft portion 28. The cutting edge portion 50 is here a cutting edge portion 50 for milling, and the ridge portion extending along the vertical direction D2 when the axis of the tool 26 is in a vertical position is the main cutting edge 50a, and the ridge portion extending along the horizontal direction D1 on the tip side (bottom side) is the secondary cutting edge 50b. The cutting edge portion 50 has a main relief surface 52 continuous with the main cutting edge 50a, a secondary relief surface 54 continuous with the secondary cutting edge 50b, and a rake surface 56, and is formed in a substantially trapezoidal shape when viewed from the bottom. The cutting edge 50 is provided in two locations at 180-degree intervals in the tool 26 shown in Figures 3(a) to (c). Here, the length from the gauge line GL to the tip of the cutting edge 50 is defined as the tool length TL, and the length from the gauge line GL to the main imaging position of the cutting edge 50 is defined as the cutting edge imaging length BL. Furthermore, the tool diameter TR is defined as twice the radial length from the center of the shaft portion 28 to the outer end of the cutting edge 50, and the cutting edge imaging diameter BR is defined as twice the radial length to the center of the rake face 56. Here, the tool 26 is described as a milling tool with its cutting edge 50 extending in the vertical direction, but it is not limited to this, and a cutting edge extending in the horizontal direction may be attached to the shaft, and the tool may also be for turning.

[0024] As shown in Figure 2, one end of the beam section 18 is connected to a tool magazine 30 that houses multiple tools 26, and the tool transport device 20 is configured to allow the tools 26 to be exchanged between the tool transport device 20 and the tool magazine 30. When a tool 26 needs to be changed, the tool transport device 20 is configured to move to the tool loading / unloading position HP (see Figure 9) in the tool magazine 30 and transfer the tool 26.

[0025] The tool wear measuring device 11 is mounted on a frame 12 and includes a guide section 32 as a second feed axis for moving the first cleaning section 36, the second cleaning section 38, and the imaging device 40 (see Figure 10) up and down relative to the tool 26. The guide section 32 is configured to move the bracket 34 on which the first cleaning section 36, the second cleaning section 38, and the imaging device 40 are arranged up and down along the vertical direction D2 using a feed axis (not shown) located inside. The tool 26, the first cleaning section 36, the second cleaning section 38, and the imaging device 40 are positioned on the same plane along the first direction D1 and the second direction D2. As a result, the tool 26, the first cleaning section 36, the second cleaning section 38, and the imaging device 40 can be aligned using only two linear feed axes and one rotation axis provided by the rotation section 22.

[0026] Figures 4(a) and 4(b) show a side view of the bottom imaging unit 42, which images the bottom surface of the tool 26, and a bottom view of the tool 26. The imaging control unit 48 operates the tool transport device 20 to move it in the horizontal direction D1, aligning the tool 26 with the bottom imaging unit 42 in the horizontal direction D1. Specifically, the tool 26 is positioned so that the radial end of the blade imaging diameter BR is at the center of the bottom imaging unit 42. The horizontal movement distance D1 of the tool transport device 20 may be determined by the imaging control unit 48 based on the tool diameter TR, or it may be arbitrarily set for each tool 26 by the operator. Next, the imaging control unit 48 operates the guide unit 32 to move the bracket 34 in the vertical direction D2, aligning the tool 26 with the bottom imaging unit 42 in the vertical direction D2. The vertical movement distance D2 of the guide section 32 may be determined by the imaging control unit 48 based on the tool length TL, or it may be arbitrarily set by the operator for each tool 26. As a result, the position of the tool 26 is set to the first imaging position TP1 (see Figure 10) of the bottom side imaging unit 42, and the imaging range IA is determined to include the tool 26. At this time, the rotation phase of the tool 26 is set to the initial phase.

[0027] Once the alignment between the tool 26 and the bottom-side imaging unit 42 is complete, the bottom-side imaging unit 42 images the secondary relief surface 54 of the tool 26. The image captured by the bottom-side imaging unit 42 is stored in the tool image storage unit 46c as a post-machined tool image associated with the phase information of the tool 26 at the time of imaging. When a post-machined tool image at a certain phase is stored in the tool image storage unit 46c, the imaging control unit 48 operates the rotation unit 22 to rotate the tool 26 by a predetermined phase interval θ (for example, 1 degree, 2 degrees, 3 degrees, etc.) and perform the next imaging. The imaging performed by rotating the tool 26 is repeated within a predetermined phase range PR. If the number of blades n is 2 or more, the phase range PR for one blade portion 50 may be set as 360 degrees / number of blades n. Here, while the rotating unit 22 is continuously rotating the tool 26, the bottom-side imaging unit 42 may take images at phase intervals θ, or the rotation of the tool 26 may be stopped after it has rotated by the phase interval θ before taking images. In addition, imaging may be performed at predetermined time intervals T instead of phase intervals θ, in which case the image is stored in the tool image storage unit 46c as a post-machined tool image associated with the rotation time from the start of rotation of the tool 26. These phase intervals θ and time intervals T may be determined by the imaging control unit 48 according to the shape and dimensions of the tool 26. For example, with a tool 26 having a relatively large tool diameter TR, if the phase interval θ is large, it may not be possible to take images at rotational phases that can be used to obtain observation images. In such cases, the imaging control unit 48 sets the phase interval θ and time interval T to a smaller value.

[0028] Figures 5(a) and 5(b) show a side view of the side imaging unit 44, which images the side of the tool 26, and a bottom view of the tool 26. The imaging control unit 48 operates the tool transport device 20 to move it in the horizontal direction D1, aligning the tool 26 with the side imaging unit 44 in the horizontal direction D1. The distance the tool transport device 20 moves in the horizontal direction D1 may be determined by the imaging control unit 48 based on the tool diameter TR, or it may be arbitrarily set by the operator for each tool 26. Next, the imaging control unit 48 operates the guide unit 32 to move the bracket 34 in the vertical direction D2, aligning the tool 26 with the side imaging unit 44 in the vertical direction D2. Specifically, the tool 26 is positioned so that the lower end of the blade imaging length BL coincides with the center position of the side imaging unit 44. The distance the guide unit 32 moves in the vertical direction D2 may be determined by the imaging control unit 48 based on the tool length TL, or it may be arbitrarily set by the operator for each tool 26. As a result, the position of the tool 26 is set to the second imaging position TP2 of the side imaging unit 44 (see Figure 10), and the imaging range IA (see Figure 4(b)) is determined to include the tool 26. At this time, the rotational phase of the tool 26 is set to the initial phase.

[0029] Once the alignment between the tool 26 and the side imaging unit 44 is complete, the side imaging unit 44 images the main relief surface 52 of the tool 26. The captured image is stored in the tool image storage unit 46c as a post-machined tool image associated with the phase information of the tool 26 at the time of imaging. When a post-machined tool image at a certain phase is stored in the tool image storage unit 46c, the imaging control unit 48 operates the rotating unit 22 to rotate the tool 26 by a predetermined phase interval θ (for example, 1 degree, 2 degrees, 3 degrees, etc.) and perform the next imaging. The imaging performed by rotating the tool 26 is repeated within a predetermined phase range PR. If the number of teeth n is 2 or more, the phase range PR for one tooth section 50 may be set as 360 degrees / number of teeth n. Here, imaging may be performed at each phase interval θ while the rotating unit 22 is continuously rotating the tool 26, or the rotation of the tool 26 may be stopped after rotating by the phase interval θ before imaging. Furthermore, imaging may be performed at a predetermined time interval T rather than a phase interval θ. In this case, the image is stored in the tool image storage unit 46c as a post-machining tool image associated with the rotation time from the start of rotation of the tool 26.

[0030] Figure 6 shows a transparent view of the inside of the first cleaning unit 36. Figures 6 through 8 show a solid end mill as the tool 26 for clarity in illustrating the effects. It goes without saying that other tools, such as the milling tool shown in Figure 3, and other turning tools, can also be cleaned. The first cleaning unit 36 ​​is configured to immerse the tool 26 in cleaning fluid WL, and the cleaning fluid is contained within the bucket-shaped interior of the first cleaning unit 36. The imaging control unit 48 operates the guide unit 32 to raise the first cleaning unit 36 ​​located on the bracket 34, allowing the tool 26 to be immersed in the cleaning fluid WL inside. This allows the tool 26 to be cleaned in the first cleaning unit 36. Furthermore, the imaging control unit 48 operates the rotating unit 22 to rotate the tool 26 immersed in the cleaning fluid WL. Therefore, if chips are attached to the tool 26, they can be easily removed, improving the cleaning effect. Furthermore, the first cleaning unit 36 ​​is equipped with an air nozzle 80, which can inject compressed air CA into the cleaning liquid WL inside. As a result, the bubbles BB generated by the compressed air CA from the air nozzle 80 can also easily remove chips adhering to the tool 26, thereby improving the cleaning effect.

[0031] Figure 7 shows another embodiment of the first cleaning unit 36. The first cleaning unit 36 ​​is equipped with a mixing device 82 for mixing compressed air CA and cleaning liquid WL, and can spray the cleaning liquid WL, which has been made into a high-pressure mist, onto the surface of the tool 26 via multiple air nozzles 80 arranged inside the first cleaning unit 36. This improves the cleaning effect of the tool 26. Furthermore, the first cleaning unit 36 ​​is equipped with a mist suction device 84 at the bottom for sucking up the mist-like cleaning liquid WL that has been sprayed onto the tool 26, dripped down the tool 26, or floated inside the first cleaning unit 36. This prevents the mist-like cleaning liquid WL from vaporizing and diffusing outside the first cleaning unit 36, thus preventing deterioration of the atmosphere inside the machine tool or factory.

[0032] Figure 8 shows a transparent view of the inside of the second cleaning unit 38. The second cleaning unit 38 is configured to blow compressed air CA onto the tool 26 in order to remove any liquid droplets from the surface of the tool 26 that has been cleaned in the first cleaning unit 36 ​​and to dry it. The second cleaning unit 38 is equipped with a pulse air generator 86 for discharging compressed air CA in a pulsed manner, and can blow pulsed compressed air CA discharged from multiple air nozzles 80 arranged inside the second cleaning unit 38 onto the surface of the tool 26. As a result, the amount of compressed air CA used can be reduced, allowing for efficient cleaning and improving the cleaning effect of the tool 26. Furthermore, the second cleaning unit 38 is equipped with a mist suction device 84 at the bottom for sucking up the mist-like cleaning liquid WL that has been sprayed onto the tool 26 and has dripped down along the tool 26, or that has floated inside the first cleaning unit 36. Therefore, the mist-like cleaning solution WL vaporizes and diffuses outside the second cleaning unit 38, preventing deterioration of the atmosphere inside the machine tool or factory.

[0033] Figure 9 shows a plan view of the inside of the tool magazine 30. Here, an endless chain-type tool magazine 30 that rotates circumferentially is configured. The tool magazine 30 is formed in a cylindrical shape and includes a drive sprocket 90 having a drive mechanism (not shown) for rotating it around a central axis, and a driven sprocket 92 that is also formed in a cylindrical shape and rotates in conjunction with the drive sprocket 90. A chain 94 is wrapped around the outer circumference of the drive sprocket 90 and the driven sprocket 92, and the chain 94 and the driven sprocket 92 are configured to rotate in conjunction with the rotation of the drive sprocket 90. A gripper 96 for attaching tools is attached to the chain 94, and an arc-shaped leaf spring (not shown) attached to the gripper 96 is configured to grip the tool 26 downwards. The tool 26 for measuring the amount of wear is moved to the tool loading / unloading position HP by the rotation of the drive sprocket 90 and handed over to the tool transport device 20. Meanwhile, the tool 26, which is attached to the spindle (not shown) in the machine tool body MT and used for machining, is moved to the tool change position CH by the rotation of the drive sprocket 90 and handed over to the machine tool body MT.

[0034] Figures 10 to 14 show a plan view and a side view of a tool wear measuring device 11 for explaining a method of measuring the amount of tool wear of a tool 26 that has been handed over to the tool transport device 20 at the tool loading / unloading position HP. As shown in Figure 10, the tool transport device 20 moves to the tool loading / unloading position HP in the tool magazine 30 and holds the tapered shank portion 28a of the tool 26 to be imaged and evaluated. Alternatively, instead of the tool transport device 20 holding the tool 26, the operator may manually attach the tool to the tool transport device 20 at the tool loading / unloading position.

[0035] When the tool transport device 20 holds the tool 26, the imaging control unit 48 operates the tool transport device 20 to transport the tool 26 along the horizontal direction D1 to a first cleaning position WP1 where the central axis of the tool 26 and the center of the first cleaning unit 36 ​​coincide in the horizontal direction D1. Next, as shown in Figure 11, the imaging control unit 48 operates the guide unit 32 to raise the bracket 34 along the vertical direction D2 until the blade portion 50 of the tool 26 is inside the first cleaning unit 36. At this time, the amount the bracket 34 is raised is determined based on the tool length TL stored in the tool information storage unit 46b. Once the blade portion 50 is inside the first cleaning unit 36, the first cleaning unit 36 ​​sprays cleaning fluid onto the blade portion 50 of the tool 26 housed inside it to clean the tool 26. Once the cleaning of the tool 26 is complete, the imaging control unit 48 operates the guide unit 32 to lower the bracket 34 along the vertical direction D2, and removes the tool 26 from inside the first cleaning unit 36.

[0036] When the bracket 34 descends and the tool 26 is removed from inside the first cleaning unit 36, the imaging control unit 48 operates the tool transport device 20 and transports the tool 26 along the horizontal direction D1 to a second cleaning position WP2 where the central axis of the tool 26 and the center of the second cleaning unit 38 coincide in the horizontal direction D1. Next, as shown in Figure 12, the imaging control unit 48 operates the guide unit 32 to raise the bracket 34 along the vertical direction D2 until the blade portion 50 of the tool 26 is inside the second cleaning unit 38. At this time, the amount the bracket 34 is raised is determined based on the tool length TL stored in the tool information storage unit 46b. Once the blade portion 50 is inside the second cleaning unit 38, the second cleaning unit 38 sprays compressed air onto the blade portion 50 of the tool 26 housed inside it to dry the tool 26 after cleaning. Once the tool 26 has finished drying, the imaging control unit 48 operates the guide unit 32 to lower the bracket 34 along the vertical direction D2, and removes the tool 26 from inside the second cleaning unit 38.

[0037] As the bracket 34 descends and the tool 26 is removed from inside the second cleaning unit 38, the imaging control unit 48 operates the tool transport device 20 to transport the tool 26 along the horizontal direction D1 to the first imaging position TP1, as shown in Figure 13. The first imaging position TP1 is positioned so that the radial end of the blade imaging diameter BR of the tool 26 coincides with the center position of the bottom side imaging unit 42. When the tool 26 moves to the first imaging position TP1, the imaging control unit 48 operates the guide unit 32 to move the bracket 34 up and down along the vertical direction D2, adjusting the focal length of the bottom side imaging unit 42 that images the tool 26. The amount of movement of the bracket 34 to adjust the focal length may be determined based on the tool length TL stored in the tool information storage unit 46b, or the automatic focus adjustment function of the bottom side imaging unit 42 may be used. At this time, the phase of the blade 50 is set to the initial phase.

[0038] Once the alignment between the tool 26 and the bottom-side imaging unit 42 is complete, the bottom-side imaging unit 42 starts imaging the secondary relief surface 54 of the tool 26. The captured image is stored in the tool image storage unit 46c as a post-machined tool image associated with the phase information of the tool 26 at the time of imaging. The imaging control unit 48 operates the rotating unit 22 to rotate the tool 26 at a predetermined phase interval θ, changing the phase, and repeatedly imaging the secondary relief surface 54 and storing the post-machined tool image associated with the phase in the tool image storage unit 46c. The imaging is repeated within a predetermined phase range PR. If the number of teeth n is 2 or more, the phase range PR for one tooth section 50 may be set as 360 degrees / number of teeth n. Here, the bottom-side imaging unit 42 may take images at phase intervals θ while the rotating unit 22 is continuously rotating the tool 26, or it may stop the rotation of the tool 26 after rotating by the phase interval θ before taking images. The imaging may be performed at a predetermined time interval T instead of a phase interval θ. In this case, the image of the secondary relief surface 54 is stored in the tool image storage unit 46c as a post-machined tool image associated with the rotation time from the start of rotation of the tool 26. The imaging control unit 48 may determine these phase intervals θ and time intervals T according to the shape and dimensions of the tool 26. For example, with a tool 26 having a relatively large tool diameter TR, if the phase interval θ is large, it may not be possible to capture an image at a rotation phase that can be used as an observation image. Therefore, the imaging control unit 48 sets the phase interval θ and time interval T to a small value. The imaging of the cutting edge 50 is repeated for n teeth by shifting the phase range PR. When the rotating unit 22 rotates the tool 26 to the phase range PR, the imaging of the secondary relief surface 54 is terminated.

[0039] When imaging of the secondary relief surface 54 is completed, the imaging control unit 48 compares the images of the multiple secondary relief surfaces 54 that have been imaged with a reference image of the secondary relief surface 54 before processing that has been stored in advance. When the image with the highest degree of agreement is identified from the difference between the images of the secondary relief surfaces 54 and the reference image, the imaging control unit 48 determines this image as the observation image of the secondary relief surface 54. These steps are repeated for n blades, and observation images of multiple secondary relief surfaces 54 are determined. Alternatively, if there are multiple blades 50 and the phase range is 360 degrees / n blades, the observation image for the first blade 50 may be determined first, and then for the second and subsequent blades 50, the observation image may be taken at a phase that is added by the phase range (360 degrees / n blades) from the phase associated when the observation image of the first blade 50 was taken. For example, as shown in Figure 3, if the tool has two cutting edges, the phase range is 360 degrees / 2 cutting edges = 180 degrees. After determining the observation image of the first cutting edge 50, the rotating part 22 rotates to a phase 180 degrees higher than the phase associated with the image of the machined tool that is the observation image of the first cutting edge 50. This causes the tool 26 to be in a phase suitable for capturing the observation image of the second cutting edge 50 relative to the bottom side imaging part 42. As a result, observation images can be efficiently determined for a tool 26 with equally spaced cutting edges 50.

[0040] Once the observation images of the sub-flag surfaces 54 for n blades are determined, as shown in Figure 14, the imaging control unit 48 operates the tool transport device 20 to transport the tool 26 along the horizontal direction D1, and further operates the guide unit 32 to move the bracket 34 up and down along the vertical direction D2, positioning the tool 26 to the second imaging position TP2. The second imaging position TP2 is positioned such that the position below the gauge line GL, which is the main imaging position of the blade 50, by a blade imaging length BL, coincides with the center position in the vertical direction D2 of the side imaging unit 44. Furthermore, the imaging control unit 48 operates the tool transport device 20 to move the tool 26 along the horizontal direction D1 and adjust the focal length of the side imaging unit 44 that images the tool 26. The amount of movement of the tool 26 to adjust the focal length may be determined based on the tool diameter TR stored in the tool information storage unit 46b, or the automatic focus adjustment function of the side imaging unit 44 may be used. At this time, the phase of the blade portion 50 is set to the initial phase.

[0041] Once the alignment between the tool 26 and the side imaging unit 44 is complete, the imaging control unit 48 operates the rotating unit 22 to rotate the tool 26 and positions the phase of the tool 26 to the phase in which the observation image of the secondary flank surface 54 was acquired. Once the phase is positioned, the imaging control unit 48 operates the side imaging unit 44 to image the main flank surface 52 and determines this post-machined tool image as the observation image of the main flank surface 52. The imaging is repeated for n teeth by changing the phase, and multiple observation images of the main flank surfaces 52 are determined. The main flank surface 52 may also be imaged at phase intervals θ or time intervals T, similar to the secondary flank surface 54. However, since the rotational phases to be imaged for the main flank surface 52 and the secondary flank surface 54 are basically the same, the initial phase before starting imaging is made the same, and the main flank surface 52 is imaged only at the same phase or rotation time as when the post-machined tool image, which became the observation image of the secondary flank surface 54, was imaged. This reduces the effort required to image the main flank surface 52.

[0042] Once observation images of the main relief surfaces 52 for n teeth are determined, the imaging control unit 48 operates the tool transport device 20 to transport the tool 26 to the tool loading / unloading position HP. Subsequently, the imaging control unit 48 transmits the observation images for n teeth to the tool wear amount measurement unit 68. Upon transmission of the observation images, the tool wear amount measurement unit 68 performs image recognition on the received observation images to evaluate the condition of the blade portion. Specifically, it measures whether there are any defects in the blade portion 50 or the amount of tool wear, and acquires this information.

[0043] Figure 15 shows an example of a portion of multiple post-machined tool images of the blade portion 50 acquired at each phase interval θ. It can be seen that the position of the blade portion 50 within the post-machined tool images P5 to P9 changes as the tool 26 rotates. The imaging control unit 48 calculates the difference between each post-machined tool image P5 to P9 and the reference image. Specifically, it generates a difference image between the post-machined tool image and the reference image, calculates the luminance value as the difference in luminance for all pixels in the difference image, and counts how many pixels exist for each luminance value. Note that the luminance value may be calculated for only a portion of the difference image. A grayscale is used for the luminance value, and it can be calculated in the range of 0 to 255. Here, a histogram of luminance value and pixel count is created for the difference image between one post-machined tool image and the reference image, and the number of pixels with the most frequent luminance value in the difference image is defined as the maximum pixel count MV. As the degree of agreement between the post-machined tool image and the reference image increases, the difference between the two images decreases, so the luminance value at which the maximum pixel count MV appears approaches 0, and the maximum pixel count MV increases. Figure 16 shows a scatter plot with the image number of the machined tool image on the horizontal axis and the maximum pixel count (MV) for each machined tool image plotted. The maximum pixel count (MV) of the machined tool image with the highest degree of agreement with the reference image is significantly larger, and can therefore be determined as the maximum value (PV) of the maximum pixel count (MV) of all machined tool images. In the example in Figure 16, the maximum pixel count (MV) of the machined tool image with image number 6 is determined as the maximum value (PV), so the machined tool image with image number 6 can be determined as the observed image with the highest degree of agreement with the reference image.

[0044] When the observation image for the number of cutting edges n is determined, the imaging control unit 48 operates the tool transfer device 20 to transfer the tool 26 to the tool loading / unloading position HP and unload the tool 26. Further, the imaging control unit 48 transmits the observation image for the number of cutting edges n to the tool wear amount measurement unit 68. The tool wear amount measurement unit 68 that has received the observation image performs image recognition on the observation image and evaluates the state of the cutting edge portion. Specifically, it checks for the presence or absence of defects in the cutting edge portion 50, measures the tool wear amount, and acquires this information. When the tool 26 has cutting edge portions 50 with the number of cutting edges n of 2 or more, only the observation image of one representative cutting edge portion 50 may be measured, or the observation images of all the cutting edge portions 50 may be measured. When the measurement is completed, the tool wear amount measurement unit 68 transmits the measurement result to the storage unit 66. The transmitted measurement result of the tool wear amount is stored in the storage unit 66 in association with (in a set with) the tool life index acquired by the tool life index measurement unit 64.

[0045] Through the flowchart of the tool life determination device 10 shown in FIG. 17 and the description of the embodiment of tool life determination using FIGS. 18 to 20, the effects of the tool life determination device 10 and the tool life determination method according to the present embodiment will be described below.

[0046] As shown in the flowchart of FIG. 17, the tool life determination process is started in step S10. Next, it proceeds to step S20, and the machine tool main body MT starts machining using a certain tool 26. When the machining is started, it proceeds to step S30, and steps S20 and S30 are repeated until the machining using the tool 26 is completed. During the machining, the tool life index measurement unit 64 measures tool life indexes such as the number of machined workpieces, machining distance, machining time, and machining work amount that are tool life indexes, and stores them in the storage unit 66 in association with the information of the tool 26 stored in the tool information storage unit 46b.

[0047] When the machining is completed, the process proceeds to step S40. The tool life determination device 10 operates the tool wear measurement device 11, and the imaging device 40 captures an image of the cutting edge portion 50 of the tool 26 to determine an observation image. The tool wear amount measurement unit 68 measures the tool wear amount of the tool 26 based on the observation image (see FIGS. 10 to 16). The tool wear amount measurement unit 68 transmits the measured tool wear amount to the storage unit 66. The storage unit 66 stores the received tool wear amount in association with the tool life index.

[0048] When the storage unit 66 stores the pair of the tool wear amount and the tool life index, the process proceeds to step S50. If the operator has a tool 26 for which the wear state is to be grasped, the operator designates the tool 26 to the calculation unit 70 via the operation input unit 60. If the tool 26 is not designated, the process proceeds to step S110 and the tool life determination process ends.

[0049] When the tool 26 is designated in step S50, the process proceeds to step S60. The calculation unit 70 extracts a record combining the tool wear amount and the tool life index from the storage unit 66. When the record is extracted, the process proceeds to step S70. The calculation unit 70 creates a scatter diagram and a histogram from the pair of the tool wear amount and the tool life index, and displays (draws) this on the display unit 72.

[0050] FIGS. 18 and 19 show an example of a histogram and a scatter diagram created from the pair of the tool wear amount and the tool life index. In the histogram of FIG. 18, the horizontal axis represents the tool wear amount, and the vertical axis represents the cumulative number of measurement values of the tool wear amount obtained in the same type of tool 26. In the scatter diagram of FIG. 19, the horizontal axis represents the tool wear amount, and the vertical axis represents the machining distance, which is the tool life index in the same type of tool 26. By these, the correlation between the tool wear amount and the tool life index can be visualized and grasped. In the example shown here, the scatter diagram and the histogram are created based on the combination of the machining distance as the tool life index and the tool wear amount, but it is not limited to this, and the number of machined workpieces, machining time, and machining work amount may be used as the tool life index or a combination thereof may be used.

[0051] Once the scatter plot and histogram are displayed on the display unit 72, the process proceeds to step S80. If the operator wishes to know the tool life index threshold for tool 26, they specify the tool wear threshold to the calculation unit 70 via the operation input unit 60. Here, the operator can specify two types of tool wear thresholds. One is a warning level tool wear threshold, which is the warning level wear threshold WT that should notify the operator that tool 26 is nearing the end of its tool life. The other is an alarm level tool wear threshold, which is the alarm level wear threshold AT that should notify the operator to replace tool 26 immediately. If no tool wear threshold is specified, the process proceeds to step S110 and the tool life determination process ends. This tool wear threshold may be a recommended value listed in the tool manufacturer's catalog, or a value determined independently by the machine tool user. Furthermore, instead of the operator inputting the tool wear threshold via the operation input unit 60, this threshold may be pre-stored in the tool information storage unit 46b, and the calculation unit 70 may automatically read it from the tool information storage unit 46b when needed.

[0052] In step S80, when a tool wear threshold for the tool 26 is specified, the process proceeds to step S90, where the calculation unit 70 calculates a tool life index threshold. Specifically, when a warning level threshold and an alarm level threshold are specified, the calculation unit 70 extracts the measured value of the tool wear and the corresponding machining distance immediately after exceeding these tool wear thresholds, and the measured value of the tool wear and the corresponding machining distance immediately before exceeding the tool wear threshold. By linearly interpolating these extracted machining distances, the calculation unit 70 calculates the distribution of machining distances corresponding to the tool wear thresholds. Furthermore, the calculation unit 70 calculates the mean and standard deviation of the calculated distribution, and sets the tool life index threshold to a value that is, for example, three times the standard deviation from the mean. Here, the calculation unit 70 calculates the warning level life index threshold WL corresponding to the warning level wear threshold WT and the alarm level life index threshold AL corresponding to the alarm level wear threshold AT as tool life index thresholds. Note that, although the thresholds were calculated using the mean and standard deviation here, the calculation unit 70 is not limited to this and may use other statistical analysis indicators, such as the F value, to calculate the thresholds.

[0053] Once the tool life index threshold is calculated, the process moves to step S100, where the display unit 72 displays the warning level wear threshold WT and the alarm level wear threshold AT in a histogram, as shown in Figure 18. Furthermore, the display unit 72 displays the data in the histogram in three cases (color-coded here): when the number of measurements displayed exceeds the warning level wear index threshold WL, when it exceeds the alarm level wear index threshold AL, and when there is no problem with tool life (indicated as "OK" in the figure). The display unit 72 also displays the warning level wear threshold WT and the alarm level wear index threshold AT in a scatter plot as shown in Figure 19, along with the warning level wear index threshold WL and the alarm level wear index threshold AL. Furthermore, the display unit 72 classifies and displays the data in the scatter plot in three cases: when the number of measurements exceeds the warning level wear index threshold WL, when it exceeds the alarm level wear index threshold AL, and when there is no problem with tool life (indicated as "OK" in the figure). This allows the operator to directly verify whether the calculation of the tool life index threshold, based on the relationship between the distribution of measured tool wear amounts and the tool wear threshold, is valid.

[0054] Furthermore, the calculation unit 70 is configured to determine that the tool 26 is worn when the current value of the tool life index exceeds the tool wear threshold, or when the current value of the tool life index exceeds the calculated tool life index threshold, and to send a spare tool replacement command to the display unit 72 to replace the worn tool 26 with a spare tool of the same type. In this way, when the display unit 72 displays the warning level tool life index threshold WL and the alarm level tool life index threshold AL, and notifies the operator of the spare tool replacement command if necessary, the process proceeds to step S110 and the tool life determination process ends. Note that when a machine tool is operated automatically without an operator, the spare tool replacement command may be sent directly from the calculation unit 70 to the machine tool control unit 62, and the worn tool may be automatically replaced with a spare tool of the same type.

[0055] The calculation unit 70 can accumulate a database of tool life index thresholds by repeating the tool life determination process. Figure 20 shows an example of the accumulated database. The storage unit 66 can record tool life index thresholds calculated from the tool wear amount and tool life index for each tool 26 information (here, program tool number PTN and function tool number FTN) stored in the storage unit 66. In the example shown in the figure, the warning level life index threshold WL ("Warning threshold" in the figure) and alarm level life index threshold AL ("Alarm threshold" in the figure), corresponding to the warning level wear amount threshold WT ("Warning threshold" in the figure) and alarm level wear amount threshold AT ("Alarm threshold" in the figure), are calculated for each tool life index threshold such as cutting work amount, cutting distance, cutting time, and number of cut workpieces, and recorded in the database. Therefore, by applying the database to other machine tools that are not equipped with the tool life determination device 10, other machine tools can properly manage tool life by monitoring only the tool life index that can be obtained in a primitive manner. Here, each tool is assigned a program tool number PTN and a function tool number FTN. The program tool number PTN is assigned corresponding to the tool storage address number in the tool magazine, and the function tool number FTN is assigned corresponding to the tool type and tool size. In this embodiment, there is a tool magazine capable of storing 20 tools, and there are 20 types of program tool numbers PTN, but there are few types of function tool numbers FTN. For example, the function tool number FTN for tool PTN001 and tool PTN019 is the same FTN101, and the function tool number FTN for tool PTN002 and tool PTN020 is the same FTN102. In other words, tools PTN019 and PTN020 are the same type and size tools as tools PTN001 and PTN002, respectively, and are spare tools that are replaced when PTN001 or PTN002 is determined to have reached the end of its tool life. Such databases are stored in the storage unit 66 and automatically displayed on the display unit 72 via the calculation unit 70, or can be displayed on the display unit 72 by the operator upon instruction from the operation input unit 60 when necessary, or can be downloaded for use in other machine tools.

[0056] The tool life determination device 10 and tool life determination method according to this embodiment include a tool wear measuring device 11 that measures the wear width of the flank face 52, 54, or rake face 56, or the amount of change in the tool diameter TR, based on an image of the cutting edge 50 of the tool 26, and a tool life index measuring unit 64 that measures at least one of the number of workpieces, machining distance, machining time, and machining work as a tool life index. Therefore, the correlation between the tool wear amount and the tool life index can be grasped for each tool 26, stored in the storage unit 66, and a tool life index threshold can be calculated from the stored correlation between the tool wear amount and the tool life index and the tool wear amount threshold. Furthermore, the tool wear measuring device 11 is located adjacent to the tool magazine 30 in a location other than the machining chamber of the machine tool body MT. Therefore, the grasp of the correlation between the tool wear amount threshold and the tool life index threshold and the calculation of the tool life index threshold can be performed automatically in parallel with the actual machining of workpieces in the machine tool body MT.

[0057] Furthermore, according to the tool life determination device 10 and tool life determination method of this embodiment, once the relationship between the tool wear threshold and the tool life index threshold for each tool 26 used to process a single workpiece is determined, it can be stored in a database. Therefore, in subsequent processing of the same type of workpiece using the same type of tool, tool life can be appropriately managed by monitoring only the tool life index without measuring the amount of tool wear. Moreover, even when there are multiple workpieces to be processed, the relationship between the tool wear threshold and the tool life index threshold for each tool 26 processing each workpiece can be automatically determined while actually processing the workpiece and stored in the database. Therefore, the relationship between the tool wear threshold and the tool life index threshold can be easily grasped for each type of workpiece and each tool used for processing, enabling efficient tool life management for the entire machine tool.

[0058] Furthermore, according to the tool life determination device 10 and tool life determination method of this embodiment, the threshold value of the tool life index calculated by the calculation unit can be imported into another machine tool, and the tool life index of the other machine tool can be measured sequentially. Therefore, when machining with the same tool and workpiece used to determine the threshold value of the tool life index on another machine tool, even if the other machine tool is not equipped with a tool life determination device, tool life can be appropriately managed by monitoring only the tool life index. In addition, the sequentially measured tool life index and the imported tool life index threshold value can be sequentially displayed on the display unit of the other machine tool. Therefore, tool life can be appropriately managed on the other machine tool while visualizing the current value of the tool life index.

[0059] Therefore, when machining with the same tool 26 and workpiece used to determine the tool life index threshold on another machine tool, tool life can be appropriately managed by utilizing the database and monitoring only the tool life index. As a result, when the tool life index measured sequentially on the other machine tool exceeds the acquired tool life index threshold, it can be determined that the tool is worn, and a spare tool replacement command can be sent to the machine tool to replace the worn tool with a spare tool of the same type. This prevents or suppresses the continuation of machining beyond the tool life index threshold on the other machine tool, thereby enabling appropriate tool life management.

[0060] As described above, the tool life determination device 10 and tool life determination method according to this embodiment can automatically determine the relationship between the tool wear threshold and the tool life index threshold while actually machining the workpiece. In this embodiment, the cleaning units 36 and 38 and the imaging device 40 are arranged integrally, but it is also possible that only the imaging unit is located inside or adjacent to the tool magazine chamber, and the cleaning unit is located in the machining chamber of the machine tool, and the tool is cleaned by spraying machining fluid onto the tool while the tool is mounted on the spindle.

[0061] Although embodiments of the tool life determination device 10 and tool life determination method have been described above, the present invention is not limited to the above embodiments. In addition to the above, it is expected that those skilled in the art will understand that various modifications of the above embodiments are possible.

[0062] 10 Tool life determination device 11 Tool wear measuring device (tool wear amount measuring unit) 50 Blade part 50a Main cutting edge 50b Sub-cutting edge 52 Main flank face 54 Sub-flank face 56 Rake face 64 Tool life index measuring unit 66 Storage unit 70 Calculation unit 72 Display unit TR Tool diameter

Claims

1. A tool life determination device for a machine tool that determines the lifespan of a tool used to process a workpiece, comprising: a tool wear amount measuring unit that captures an image of the cutting edge of the tool inside the machine tool and measures the wear width of the flank face or rake face, or the amount of change in the tool diameter, based on the image; a tool life index measuring unit that measures at least one of the number of workpieces to be processed, processing distance, processing time, and processing work amount, which are acquired when the workpiece is processed based on a processing program and processing conditions input to the machine tool, as a tool life index; a storage unit that sequentially stores the measured tool wear amount and tool life index as a pair for each tool; and a calculation unit that calculates a threshold value for the tool life index using the stored pair of tool wear amount and tool life index, and a threshold value for the input tool wear amount.

2. The tool life determination device for a machine tool according to claim 1, further comprising a display unit that sequentially displays the threshold value of the tool life index calculated by the calculation unit and the current value of the tool life index measured by the tool life index measuring unit on the same screen.

3. The tool life determination device for a machine tool according to claim 1, wherein the calculation unit determines that the tool is worn when the current value of the tool wear amount measured by the tool wear amount measuring unit exceeds a threshold value of the tool wear amount, or when the current value of the tool life index measured by the tool life index measuring unit exceeds a threshold value of the calculated tool life index, and transmits a spare tool replacement command to the machine tool to replace the worn tool with a spare tool of the same type.

4. A method for determining tool life using the tool life determination device for a machine tool described in claim 1, comprising the steps of: importing a threshold value of the tool life index calculated by the calculation unit into another machine tool; sequentially measuring the tool life index of the other machine tool; and displaying the sequentially measured tool life index and the acquired threshold value of the tool life index on the display unit of the other machine tool.

5. A method for determining tool life using the tool life determination device for a machine tool described in claim 1, comprising the steps of: importing a threshold value of the tool life index calculated by the calculation unit into another machine tool; sequentially measuring the tool life index of the other machine tool; and determining that the tool is worn when the tool life index measured sequentially in the other machine tool exceeds the threshold value of the imported tool life index, and sending a spare tool replacement command to the other machine tool to replace the worn tool with a spare tool of the same type.

Images