Method for determining tool life in machine tools

Abstract

This invention provides a tool life determination device and a tool life determination method that can automatically determine the relationship between the tool wear threshold and the tool life index threshold while actually machining a workpiece. [Solution] The tool life determination device 10 for a machine tool MT comprises: a tool wear measuring device 11 that captures an image of the cutting edge 50 of the tool 26 inside the machine tool MT and measures the wear width of the flank face or rake face, or the amount of tool wear representing the change in tool diameter; a tool life index measuring unit 64 that measures at least one of the number of workpieces, machining distance, machining time, and machining work amount, which are acquired when a workpiece is machined based on the machining program and machining conditions, as a tool life index; a storage unit 66 that sequentially stores the tool wear amount and the tool life index as a pair; and a calculation unit 70 that calculates a threshold for the tool life index using the pair of tool wear amount and tool life index and the input threshold for the tool wear amount.

Description

Technical Field

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

Background Art

[0002] In a factory where workpieces are processed and mass-produced by a machine tool, the life management of the tools used for processing is an important factor directly related to production costs. If it is necessary to replace with a new tool before the tool life reaches, the cost will increase unnecessarily. Also, if the tool is continued to be used even after the tool life reaches, the quality of the processed surface will deteriorate, the cutting resistance will increase, and the tool may break, resulting in the possibility of the workpiece becoming a defective product. Therefore, it is preferable to be able to replace with a new tool immediately before the tool life reaches.

[0003] In order to replace with a new tool immediately before the life reaches, it is necessary to correctly grasp that the tool life has reached at the processing site. For this reason, generally, the wear amount of the cutting edge of the tool is sequentially measured quantitatively, and when the wear amount exceeds the tool wear amount threshold value determined in the factory, a warning signal is issued to prompt the replacement of the tool, and if the tool is not replaced, an alarm signal is issued to forcibly stop the processing. 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 (the integrated movement distance of the cutting feed), and determines the life by comparing this measured value with the reference wear width. However, there may be a case where the tool wear amount threshold value is exceeded when the predetermined cutting distance is reached, and tool breakage or workpiece defects may occur.

[0004] On the other hand, looking at the machining site, data such as the number of workpieces cut, cutting distance, cutting time (cumulative cutting feed time), and cutting work (cumulative power consumption of the spindle motor while cutting feed is being performed), which are thought to have a strong correlation with tool life, can be easily and continuously acquired by the machine tool control unit. Therefore, it is conceivable to use these as tool life evaluation indices (hereinafter referred to as tool life indices) to evaluate tool life. In other words, if the correlation between the amount of tool wear and the tool life index can be understood in the machining of a workpiece using a single tool, it is possible to understand that the tool life has been reached by the tool life index threshold without directly measuring the amount of tool wear, and to manage tool life by replacing the worn tool with a spare tool at the appropriate time. However, there are many types of tools, such as end mills, face milling cutters, drills, boring tools, turning tools, and cutting tools, and their materials also vary widely, such as high-speed steel, cemented carbide, ceramic, and whether or not they are coated. In addition to these, tools have many other parameters, such as the number of cutting edges, whether they are solid or insert type, length, and diameter. Furthermore, the workpieces subjected to machining using tools are diverse in material (cast iron, steel, aluminum, copper, titanium, etc.), shape (round, square, etc.), and depth of cut (with significant variation). In addition to these, machining conditions of the workpiece, such as rotational speed, feed rate, depth of cut, and type and amount of cutting fluid, can also be parameters. Therefore, it is practically impossible to determine the correlation between tool wear and tool life index for each of these numerous parameters by conducting machining tests in advance. [Prior art documents] [Patent Documents]

[0005] [Patent Document 1] Japanese Patent Publication No. 2002-337041 [Overview of the project] [Problems that the invention aims to solve]

[0006] In view of the above circumstances, the present invention aims to provide a tool life determination device and a tool life determination method that can automatically determine the relationship between a tool wear threshold and a tool life index threshold while actually machining a workpiece. [Means for solving the problem]

[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 rake face, or the amount of tool wear representing the change in 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 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 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. [Effects of the Invention]

[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. [Brief explanation of the drawing]

[0013] [Figure 1] Figure 1 shows a block diagram of the tool life determination device according to this embodiment. [Figure 2]FIG. 2 shows a perspective view of the tool wear measurement device according to the present embodiment. [Figure 3] FIG. 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). [Figure 4] (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 a bottom view of the tool. [Figure 5] (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 a bottom view of the tool. [Figure 6] FIG. 6 shows a transparent view of the inside of the first cleaning unit. [Figure 7] FIG. 7 shows a transparent view of the inside of the first cleaning unit according to another aspect. [Figure 8] FIG. 8 shows a transparent view of the inside of the second cleaning unit. [Figure 9] FIG. 9 shows a plan view of the tool magazine. [Figure 10] FIG. 10 shows a plan view and a side view of the tool wear measurement device according to the present embodiment. [Figure 11] FIG. 11 shows a plan view and a side view of the tool wear measurement device that cleans the tool by the first cleaning unit. [Figure 12] FIG. 12 shows a plan view and a side view of the tool wear measurement device that cleans the tool by the second cleaning unit. [Figure 13] FIG. 13 shows a plan view and a side view of the tool wear measurement device that images the bottom of the tool by the first imaging unit. [Figure 14] FIG. 14 shows a plan view and a side view of the tool wear measurement device that images the side of the tool by the second imaging unit. [Figure 15] FIG. 15 shows an example of a plurality of processed tool images including the cutting edge. [Figure 16] FIG. 16 shows an example of detecting the maximum luminance value for each processed tool image. [Figure 17] FIG. 17 shows a flowchart of tool life determination according to the present embodiment. [Figure 18] FIG. 18 shows a histogram of the number of tool life determination cases with respect to the tool wear amount. [Figure 19] FIG. 19 shows a correlation diagram between the tool wear amount and the tool life index. [Figure 20] FIG. 20 shows a database of the correlation between the tool wear amount and the tool life index.

Embodiments for Carrying Out the Invention

[0014] Hereinafter, a tool life determination apparatus and a tool life determination method according to an embodiment will be described with reference to the accompanying drawings. The same or corresponding elements are denoted by the same reference numerals, and redundant descriptions will be omitted. For ease of understanding, the scale of the drawings may be changed for the description.

[0015] FIG. 1 shows a block diagram of a tool life determination apparatus 10. The tool life determination apparatus 10 is configured integrally with a machine tool main body MT (machine tool) or is disposed adjacent to the machine tool main body MT. The tool life determination apparatus 10 includes a tool wear measurement device 11 as a tool wear amount measurement unit for measuring the tool wear amount, which is the wear amount of the cutting edge portion 50 of the tool 26 used for machining, and a tool life index measurement unit 64 for measuring a tool life index. Here, the tool wear amount of the tool 26 refers to the wear width of the flank faces 52, 54, or the rake face 56, or the change amount of the tool diameter TR (see FIG. 3), and one or more of these are used for tool life determination. Further, the tool life index refers to the number of processed workpieces machined by the tool 26 so far, the machining distance, the machining time (the integrated time of the executed machining), and the machining work amount (the integrated power consumption of the main spindle motor during the execution of machining), 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 them sequentially, 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 machining, 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, determines the image with the highest degree of agreement with the reference image from among the multiple post-machining tool images as the observation image, and performs image analysis on the determined 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 notify the user of the warning or alarm to advise against continuing 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 location, and the tool wear measuring device may also be located inside the tool magazine chamber of the machine tool body. The tool wear measuring device 11 has both a function of measuring the amount of tool wear and a function of transporting tools, 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 vertical direction D2, and a beam section 18 spanning between the two support columns 16 and extending along a first horizontal direction D1 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 is a rotating section 22, which serves as a third feed shaft, having a drive unit such as a servo motor and 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 side and bottom views 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 defined as 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 exchange of tools 26 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 teeth n is 2 or more, the phase range PR for one tooth portion 50 may be set as 360 degrees / number of teeth 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. Note that imaging may be performed at predetermined time intervals T instead of phase intervals θ. In this 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 the tool 26's rotation. 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, a large phase interval θ may result in the image not being taken at a rotation phase that can be used to create an observation image. In such cases, the imaging control unit 48 sets the phase interval θ and time interval T to smaller values.

[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 horizontally in the D1 direction, aligning the tool 26 with the side imaging unit 44 horizontally in the D1 direction. The distance the tool transport device 20 moves horizontally in the D1 direction 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 vertically in the D2 direction, aligning the tool 26 with the side imaging unit 44 vertically in the D2 direction. 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 vertically in the D2 direction 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 (see Figure 10) of the side imaging unit 44, 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 instead of 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 the cleaning liquid WL, and the cleaning liquid 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 liquid 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 liquid 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 fluid 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 the cleaning liquid WL, which has been made into a high-pressure mist, can be sprayed 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 and dripped down the tool 26, or that has 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 and dry any liquid droplets from the surface of the tool 26 that has been cleaned in the first cleaning unit 36. 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. This reduces the amount of compressed air CA used, 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 dripped down along the tool 26, or that has floated inside the first cleaning unit 36. This prevents the mist-like cleaning liquid WL from vaporizing and diffusing outside the second cleaning unit 38, thus 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 comprises a drive sprocket 90 having a drive mechanism (not shown) for rotating it around a central axis, and a driven sprocket 92 formed in a cylindrical shape that 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. Once the tool 26 has moved 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. 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 captured with a reference image of the secondary relief surface 54 before processing, which 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 captured at a phase that is added by the phase range (360 degrees / n blades) from the phase associated with when the observation image of the first blade 50 was captured. 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 surface 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 cutting edge 50 acquired at each phase interval θ. It can be seen that the position of the cutting edge 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. 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 to be 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 to be the maximum value PV, so the machined tool image with image number 6 can be determined to be the observed image as it has the highest degree of agreement with the reference image.

[0044] Once observation images for n blades 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 and unloads the tool 26. Furthermore, the imaging control unit 48 transmits the observation images for n blades to the tool wear amount measurement unit 68. The tool wear amount measurement unit 68, upon receiving the observation images, performs image recognition on the images and evaluates the condition of the blades. Specifically, it checks for any defects in the blades 50 and measures the amount of tool wear, acquiring this information. If the tool 26 has two or more blades 50, it may measure only the observation image of one representative blade 50, or it may measure all the observation images of all blades 50. Once the measurement is complete, the tool wear amount measurement unit 68 transmits the measurement results to the storage unit 66. The transmitted tool wear measurement results are stored in the storage unit 66 in association (as a pair) with the tool life index acquired by the tool life index measurement unit 64.

[0045] The effects and advantages of the tool life determination device 10 and tool life determination method according to this embodiment will be explained below through the flowchart of the tool life determination device 10 shown in Figure 17 and the description of the tool life determination embodiment using Figures 18 to 20.

[0046] As shown in the flowchart in Figure 17, the tool life determination process is started in step S10. Next, the process moves to step S20, where the machine tool body MT starts machining using a certain tool 26. Once machining has started, the process moves to step S30, and steps S20 and S30 are repeated until machining using the tool 26 is completed. The tool life index measuring unit 64 measures tool life indicators such as the number of workpieces, machining distance, machining time, and machining work volume while machining is in progress, and stores the information of the tool 26 stored in the tool information storage unit 46b in the storage unit 66 in association with these indicators.

[0047] Once machining is complete, the process moves to step S40, where the tool life determination device 10 activates the tool wear measuring device 11, and the imaging device 40 captures an image of the cutting edge 50 of the tool 26, determining the observation image. The tool wear amount measuring unit 68 measures the amount of tool wear of the tool 26 based on the observation image (see Figures 10 to 16). The tool wear amount measuring unit 68 transmits the measured amount of tool wear to the storage unit 66. The storage unit 66 stores the received amount of tool wear in association with the tool life index.

[0048] Once the memory unit 66 stores the pair of tool wear amount and tool life index, the process moves to step S50. If the operator has a tool 26 whose wear status they want to check, they specify that tool 26 to the calculation unit 70 via the operation input unit 60. If no tool 26 is specified, the process moves to step S110 and the tool life determination process ends.

[0049] When tool 26 is specified in step S50, the process proceeds to step S60, where the calculation unit 70 extracts a record from the storage unit 66 that combines tool wear amount and tool life index. Once the record is extracted, the process proceeds to step S70, where the calculation unit 70 creates a scatter plot and a histogram from the combination of tool wear amount and tool life index, and displays (draws) them on the display unit 72.

[0050] Figures 18 and 19 show examples of histograms and scatter plots created from a combination of tool wear and tool life index. In the histogram in Figure 18, the horizontal axis shows the tool wear amount, and the vertical axis shows the cumulative number of tool wear measurements obtained for the same type of tool 26. In the scatter plot in Figure 19, the horizontal axis shows the tool wear amount, and the vertical axis shows the machining distance, which is the tool life index for the same type of tool 26. These allow for the visualization and understanding of the correlation between tool wear and tool life index. In the examples shown here, the scatter plots and histograms are created based on a combination of machining distance and tool wear as tool life indexes, but the tool life index is not limited to this, and the number of workpieces, machining time, and machining work volume, 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, the level at which the operator should be notified 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, the level at which the operator should be notified that tool 26 should be replaced 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. Alternatively, instead of the operator inputting this tool wear threshold via the operation input unit 60, it may be stored in advance 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 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 tool wear and the corresponding machining distance immediately after exceeding these tool wear thresholds, and the measured value of tool wear and the corresponding machining distance immediately before exceeding the tool wear threshold. By linear interpolation or the like, 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 number of measurements shown in the histogram in three cases (color-coded here): when it 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 index 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 it 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 result of the tool life index threshold, based on the relationship between the distribution of measured tool wear values ​​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, 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 memory 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 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. [Explanation of Symbols]

[0062] 10 Tool life determination device 11. Tool wear measuring device (tool wear amount measuring unit) 50 Blade 50a Main cutting blade 50b Sub-cutting blade 52 Main escape side 54 Secondary escape route 56 Scoop surface 64 Tool life index measurement section 66 Memory section 70 Calculation Unit 72 Display section TR tool diameter

Claims

1. A tool life determination method using a tool life determination device for a machine tool, comprising: a tool wear amount measuring unit that captures an image of the cutting edge of a tool inside the machine tool and measures a tool wear amount that represents the wear width of the flank face or rake face, or the change in tool diameter, based on the image; a tool life index measuring unit that measures at least one of the number of workpieces, machining distance, machining time, and machining work amount, which are obtained when a workpiece is machined based on a machining program and machining 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 distribution of the tool life index corresponding to a threshold of the input tool wear amount from the stored pairs of the tool wear amount and tool life index, and calculates a threshold of the tool life index by statistically analyzing the calculated distribution, wherein The steps include: importing the threshold value of the tool life index calculated by the calculation unit into another machine tool; The steps include sequentially measuring the tool life index of the other machine tool, The steps include displaying the tool life index measured sequentially and the threshold value of the acquired tool life index on the display unit of the other machine tool, A method for determining the tool life of a machine tool, characterized by including the following:

2. A tool life determination method using a tool life determination device for a machine tool, comprising: a tool wear amount measuring unit that captures an image of the cutting edge of a 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, machining distance, machining time, and machining work amount, which are obtained when a workpiece is machined based on a machining program and machining 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 distribution of the tool life index corresponding to a threshold of the input tool wear amount from the stored pairs of the tool wear amount and tool life index, and calculates a threshold of the tool life index by statistically analyzing the calculated distribution, wherein The steps include: importing the threshold value of the tool life index calculated by the calculation unit into another machine tool; The steps include sequentially measuring the tool life index of the other machine tool, The steps include: determining that the tool is worn when the tool life index, which is measured sequentially in the other machine tool, exceeds a threshold value of the acquired 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; A method for determining the tool life of a machine tool, characterized by including the following:

Images