WO2022172520A1

WO2022172520A1 - Machine tool

Info

Publication number: WO2022172520A1
Application number: PCT/JP2021/039976
Authority: WO
Inventors: Tomoaki Yamada; Junichi Kubota; Akito Shigekane
Original assignee: Dmg Mori Co., Ltd.
Priority date: 2021-02-15
Filing date: 2021-10-29
Publication date: 2022-08-18
Also published as: JP6884932B1; JP2022123916A

Abstract

A machine tool includes: a storage chamber for accommodating a plurality of tools; a machining chamber for being used for machining with a tool; a shutter for closing an opening in a partition between the storage chamber and the machining chamber; a tool support for supporting a tool for replacement in the storage chamber; an imaging unit located in the storage chamber; an illumination unit fixed to the shutter, the illumination unit illuminating the tool supported by the tool support; and a shutting mechanism for moving the shutter along a longitudinal direction of the tool to close the opening. The illumination unit is integrally moved with the shutter, and the tool is imaged by the imaging unit.

Description

MACHINE TOOL

Cross-reference to Related Application(s)

This application claims priority to Japanese Patent Application No. 2021-021380 filed on February 15, 2021, which is incorporated herein by reference in its entirety.

The present invention relates to a technology for testing tools in machine tools.

Examples of machine tools include a turning center that moves a tool relative to a rotating workpiece, a machining center that moves a rotating tool relative to a workpiece, and a combined machine having combined functions of a turning center and a machining center. A machine tool includes a tool changer called an automatic tool changer (ATC), and machine a workpiece into a desired shape by changing tools among a plurality of kinds of tools in the process of machining. An ATC changes tools between a tool storage part (a magazine, etc.) and a tool holding part (a spindle, etc.).

In a case where a tool after being used has an abnormality such as a fracture, a breakage, or swarf wound therearound in such a machine tool, the tool (hereinafter also referred to as a “faulty tool”) cannot be used in this state for next machining. Thus, a technology for imaging a blade shape of a tool before and after being used by a camera and determining whether or not the tool is a faulty tool on the basis of the images before and after use has been proposed (Patent Literature 1).

In a tool test, a tool is illuminated from one side thereof and imaged by a camera set on the other side thereof, for example. Transmitted illumination is used to silhouette the tool, and the outline of the tool is identified on the basis of the silhouette. When a normal outline shape cannot be obtained, the tool can be determined to be a faulty tool.

JP 2015-131357 A

The accuracy of such a tool test depends on the contrasts of the images. A silhouette of a tool need to be obtained in good condition, and a portion to be imaged of a tool (from a blade base end to a blade edge, for example) therefore has to be lighted uniformly. Tools that are accommodated in a tool storage part, however, vary in size, and it is difficult to uniformly light a tool that is excessively large relative to the illumination range. Use of a large illumination device for large tools, however, is disadvantageous in terms of cost.

An embodiment of the present invention is a machine tool. The machine tool includes: a storage chamber for accommodating a plurality of tools; a machining chamber for being used for machining with a tool; a shutter for closing an opening in a partition between the storage chamber and the machining chamber; a tool support for supporting a tool for replacement in the storage chamber; an imaging unit located in the storage chamber; an illumination unit fixed to the shutter, the illumination unit illuminating the tool supported by the tool support; and a shutting mechanism for moving the shutter along a longitudinal direction of the tool to close the opening. The illumination unit is integrally moved with the shutter, and the tool is imaged by the imaging unit.

According to the present invention, high-contrast images can be achieved regardless of the tool lengths, and tool shapes can be detected with sufficient accuracy.

FIG. 1 is a perspective view of an external appearance of a machine tool according to an embodiment. FIG. 2 is a side view illustrating an internal configuration of tool storage equipment. FIG. 3 is a perspective view schematically illustrating a structure in a storage chamber. FIG. 4 is a front view schematically illustrating a structure around a boundary between the storage chamber and a machining chamber. FIG. 5 is a hardware configuration diagram of the machine tool and an image processing device. FIG. 6 is a functional block diagram of the image processing device. FIGS. 7A to 7C are diagrams illustrating a method for illuminating a subject tool during imaging. FIGS. 8A and 8B are diagrams illustrating an image processing method. FIG. 9 is a flowchart illustrating processes of a pre-use tool shape data acquiring process. FIG. 10 is a flowchart illustrating processes of a tool testing process. FIGS. 11A and 11B are diagrams illustrating illumination and imaging methods according to a modification.

An embodiment of the present invention will now be described with reference to the drawings. A machine tool according to the present embodiment is a machining center for machining a workpiece into a desired shape with tools being changed as appropriate.

FIG. 1 is a perspective view of an external appearance of the machine tool according to the embodiment. The front-back direction, the left-right direction, and the up-down direction of the machine tool 1 as viewed from the front will be referred to as a Z-axis direction, an X-axis direction, and a Y-axis direction, respectively.
The machine tool 1 includes machining equipment 2 and tool storage equipment 4. A cover 6 (an equipment housing) is provided to cover the equipment. The cover 6 contains a machining chamber 8 on the right side and a storage chamber 10 on the left side in front view. In the machining chamber 8, machining is performed by the machining equipment 2. In the storage chamber 10, a plurality of tools are stored by the tool storage equipment 4 and tool replacement is performed by an ATC, which is not illustrated (details thereof will be described later).

A console 12 is installed on a right side face of the cover 6. An image processing device 14 is connected to the machining chamber 8. A user can remotely monitor a working status of the machine tool 1 by using the image processing device 14. The image processing device 14 may be a common laptop personal computer (PC) or tablet computer. In a modification, the image processing device may be a device inside the machining chamber 8.

FIG. 2 is a side view illustrating an internal configuration of the tool storage equipment 4. FIG. 2 corresponds to a left side view of the machine tool 1, and illustrates a state in which a left side face of the cover 6 is removed for convenience of explanation. In addition, a magazine (which will be described later) is illustrated in a partially cutout manner.

The tool storage equipment 4 includes a disk type magazine 20. A plurality of pots 22 are arranged along an outer circumferential face of the magazine 20, and each can accommodate a tool T. The pots 22 each coaxially hold a tool T, and thus a plurality of tools are held radially around a rotating shaft 24 of the magazine 20. In a modification, a magazine of a chain type or other types may be used.

The magazine 20 turns around the rotating shaft 24, and horizontally supports a tool T for replacement at a front end position thereof (a right end position in FIG. 2). Specifically, the pots 22 of the magazine 20 each function as a “tool support” for supporting a tool T for replacement (also referred to as a “subject tool Tx”) in the storage chamber 10 in a standby state.

A partition 26 separating the storage chamber 10 from the machining chamber 8 has an opening 28, and a shutter 30 for closing the opening 28 is provided. In addition, a shutting mechanism 32 for moving the shutter 30 along the longitudinal direction of a subject tool Tx to open and close the opening 28 is provided. An ATC 34 is located in the storage chamber 10. The ATC 34 replaces a tool T (also referred to as a “used tool Tu”) held by a tool spindle (not illustrated) in the machining chamber 8 with a tool T (also referred to as a “pre-use tool Tp”) held in a standby state in the storage chamber 10. Tool replacement is performed in a state in which the shutter 30 is open.

A subject tool Tx is horizontally supported as a tool for replacement in the storage chamber 10. The subject tool Tx can be a pre-use tool Tp just before tool replacement, and a used tool Tu just after tool replacement. In the present embodiment, an image of a pre-use tool Tp and an image of a used tool Tu are taken for the same tool. The condition of the used tool Tu (whether the used tool Tu is a faulty tool, etc.) is determined on the basis of comparison between the image of the pre-use tool Tp and the image of the used tool Tu. Details of the determination will be described later.

FIG. 3 is a perspective view schematically illustrating a structure in the storage chamber 10. FIG. 4 is a front view schematically illustrating a structure around the boundary between the storage chamber 10 and the machining chamber 8.
As illustrated in FIG. 3, the subject tool Tx is horizontally supported in the storage chamber 10. The shutter 30 is driven in the longitudinal direction of the subject tool Tx by the shutting mechanism 32, to open and close the opening 28. Note that the “longitudinal direction” of the subject tool Tx is a direction along the axis of the pot 22 that supports the subject tool Tx in the storage chamber 10 and corresponds to the “Z-axis direction”. A “short direction” of the subject tool Tx is a direction perpendicular to the longitudinal direction, and can be the “X-axis direction” or the “Y-axis direction”. The shutting mechanism 32 includes a feed screw mechanism 33 and a servomotor 35 for driving the feed screw mechanism 33.

As also illustrated in FIG. 4, the ATC 34 is located in a space between the subject tool Tx and the shutter 30. The ATC 34 includes a main unit 36 including a motor, and an arm 38 mounted on a rotating shaft of the motor. The arm 38 has a symmetrical shape with respect to the rotating shaft, and includes grip parts 40 at respective ends thereof. The grip parts 40 each include a fixed jaw 42 and a movable jaw 44. The grasping movement of each grip part 40 is achieved by driving the movable jaw 44.

The ATC 34 includes a translation mechanism for moving the arm 38 in the axial direction, and a rotation mechanism for rotating the arm 38 about the axis. The motor includes a first motor for driving the translation mechanism, and a second motor for driving the rotation mechanism. Because such mechanisms themselves are known, detailed description thereof is omitted herein.

While the ATC 34 is not operating, the ATC 34 is in a state in which the longitudinal direction of the arm 38 is in the vertical direction as illustrated in FIG. 4. The ATC 34 is thus accommodated in the storage chamber 10 with the shutter 30 closed. While the ATC 34 is operating, a pre-use tool Tp is in a standby state on one side (on the storage chamber 10 side) of the axis of the arm 38, and a used tool Tu is in a standby state on the other side (on the machining chamber 8 side) thereof. In this state, the shutter 30 is opened.

When the ATC 34 operates, the arm 38 turns, and the pair of grip parts 40 grasp the pre-use tool Tp and the used tool Tu. At this point, the arm 38 is temporarily located across the opening 28. When the translation mechanism and the rotation mechanism are then driven, tools are detached from and attached to the pot 22 and the tool spindle 37, and tool replacement is thus performed. Because such operation of the ATC is known, detailed explanation thereof is omitted herein.

A camera 50 is located above a position at which the subject tool Tx is held, and an illumination device 52 is located below the position. The camera 50 includes an image sensor (image pickup device) such as a complementary metal oxide semiconductor (CMOS) or a charge-coupled device (CCD). The camera 50 in the present embodiment has a resolution of about one million pixels (1224×1024). In addition, the camera 50 is capable of capturing a maximum of 80 images per second.

The illumination device 52 is fixed to a lower portion of the shutter 30. The illumination device 52 functions as an “illumination unit” that lights the subject tool Tx at an oblique angle from below. The camera 50 functions as an “imaging unit” that images the subject tool Tx at an oblique angle from above. The camera 50 and the illumination device 52 are located on sides opposite each other with respect to the subject tool Tx. Transmitted illumination of the illumination device 52 enables the camera 50 to obtain high-contrast images in which outline positions of tools T are easily viewable.

The description refers back to FIG. 3, in which the distance between the camera 50 and the subject tool Tx (working distance: hereinafter also referred to as “WD”) is set so that a portion to be imaged of the subject tool Tx can be contained in one screen (see FIG. 4). Note that a “portion to be imaged” refers to a portion that needs to be tested (also referred to as a “portion to be tested”) to determine whether or not the subject tool Tx is a faulty tool. The portion to be imaged is preset. In the present embodiment, the portion to be imaged is a portion of the subject tool Tx from a base end supported by a pot 22 to a blade edge thereof. In a modification, the portion to be imaged may be a portion from a blade base end to a blade edge.

As also illustrated in FIG. 4, the rotation axis Lt of the tool spindle 37, the rotation axis Lx of the ATC 34, the moving direction of the shutter 30, and the longitudinal direction of the subject tool Tx at a standby position for tool replacement are designed to be parallel to each other (parallel to the Z axis).

Although not illustrated in FIGS. 3 and 4, it is needless to say that such structures as the main unit 36 of the ATC 34, the shutting mechanism 32, and the camera 50 are stably fixed to such a structure as a wall surface or a beam in the storage chamber 10.

FIG. 5 is a hardware configuration diagram of the machine tool 1 and the image processing device 14.
The machine tool 1 includes a machining controller 60 and an operation controller 62 in addition to the machining equipment 2, the tool storage equipment 4, and the ATC 34 described above. The machining controller 60 functions as a numerical controller that outputs control signals to the machining equipment 2 in accordance with a machining program. The machining equipment 2 drives a tool spindle (not illustrated) to machine a workpiece in accordance with instructions from the machining controller 60.

The operation controller 62 includes the console 12, and controls the machining controller 60. The ATC 34 takes out a tool from the tool storage equipment 4 and replaces a used tool Tu held on the tool spindle with the pre-use tool Tp taken out from the tool storage equipment 4 in accordance with a replacement instruction from the machining controller 60.

The image processing device 14 mainly performs image processing such as recognition of tool shapes. As described above, the image processing device 14 may be part of the operation controller 62. Alternatively, the whole equipment including the image processing device 14 may be referred to as a “machine tool 1”.

FIG. 6 is a functional block diagram of the image processing device 14.
The components of the image processing device 14 are implemented by hardware including computing units such as central processing units (CPUs) and various auxiliary processors, storage devices such as memories and storages, and wired or wireless communication lines that connect these units and devices, and software that is stored in the storage devices and supplies processing instructions to the computing units. Computer programs may be constituted by device drivers, operating systems, various application programs on upper layers thereof, and a library that provides common functions to these programs. Blocks to be described below do not refer to configurations in units of hardware but to blocks in units of functions.

Note that the operation controller 62 and the machining controller 60 may also be implemented by hardware including computing units such as processors, storage devices such as memories and storages, and wired or wireless communication lines that connect these units and devices, and software and programs that are stored in the storage devices and supply processing instructions to the computing units, which are executed on operation systems separate from the image processing device 14.

The image processing device 14 includes a user interface processing unit 70, a data processing unit 72, a data storage unit 74, and a communication unit 76.
The user interface processing unit 70 performs processes relating to user interfaces such as receiving operations made by a user, displaying images, and outputting audio. The communication unit 76 performs communication with the operation controller 62. The data processing unit 72 performs various processes on the basis of data obtained by the user interface processing unit 70 and data stored in the data storage unit 74. The data processing unit 72 also functions as an interface of the user interface processing unit 70, the data storage unit 74, and the communication unit 76. The data storage unit 74 stores various programs and set data.

The user interface processing unit 70 includes an input unit 80 and an output unit 82.
The input unit 80 receives inputs made by the user via a touch panel or a hardware device such as a handle. The output unit 82 provides the user with various information by image display or audio output. The output unit 82 includes an informing unit 84. When a predetermined abnormality condition, such as an error of a tool to be replaced (detection of a faulty tool), is met, the informing unit 84 informs the user of occurrence of relevant events (details thereof will be described later).

The communication unit 76 includes a receiving unit 110 that receives data from the operation controller 62, and a transmitting unit 112 that transmits data and commands to the operation controller 62.

The data processing unit 72 includes a movement controlling unit 90, an imaging processing unit 92, a shape reproducing unit 94, a tool managing unit 96, and a determination processing unit 98.
The movement controlling unit 90 drives and controls the shutting mechanism 32 to control opening and closing of the shutter 30 (that is, the movement of the illumination device 52). The imaging processing unit 92 controls the camera 50 to image the subject tool Tx. The shape reproducing unit 94 generates “tool shape data”, which are data indicating the shape of the subject tool Tx on the basis of the image. The tool managing unit 96 registers a tool ID and the tool shape data in association with each other for each subject tool Tx in the data storage unit 74.

The determination processing unit 98 determines whether a subject tool Tx has an abnormality such as a fracture, a breakage, or swarf wound therearound (whether or not the subject tool Tx is a faulty tool) on the basis of the image of the subject tool Tx or on the basis of the tool shape data. When the determination processing unit 98 determines that the subject tool Tx has an abnormality, the informing unit 84 informs the user of the same. The determination processing unit 98 may instruct the operation controller 62 to display the same on the console 12. When a used tool Tu is determined to be a faulty tool, the tool managing unit 96 associates the information of being a faulty tool with the tool ID, and registers the associated information as tool information into the data storage unit 74.

The data storage unit 74 includes a tool information storage unit 100 and a shape data storage unit 102. The tool information storage unit 100 stores information (tool information) of each of the tools T accommodated in the magazine 20 in association with the tool ID. The tool information includes information such as the type, the shape, the size, and the length of each tool, for example. The tool information may further include information such as cumulative total hours of use and a cumulative total number of uses. The data storage unit 74 also temporarily stores taken images.

The tool information storage unit 100 updates the tool information each time tool replacement is performed. When a subject tool Tx is determined to be a faulty tool as described above, the tool information storage unit 100 adds the information of being a faulty tool to the tool information. After the determination, the tool managing unit 96 prohibits use of the tool T, which is a faulty tool, that is, tool replacement with the tool T as a pre-use tool Tp by the ATC 34.

The shape data storage unit 102 stores the tool shape data generated by the shape reproducing unit 94 in association with the tool ID. In the present embodiment, the tool shape data are generated before and after tool replacement. Thus, for each subject tool Tx, the tool shape data of a pre-use tool Tp (hereinafter also referred to as “pre-use tool shape data”) and the tool shape data of a used tool Tu (hereinafter also referred to as “used tool shape data”) are stored in association with the tool ID. The determination processing unit 98 can determine whether or not a used tool Tu is a faulty tool by comparing the pre-use tool shape data and the used tool shape data of the same tool with each other.

Next, a method for imaging a tool will be explained.
FIGS. 7A to 7C are diagrams illustrating a method for illuminating a subject tool Tx during imaging. FIGS. 7A to 7C illustrate processes of imaging. Upper parts of FIGS. 7A to 7C are side views, and lower parts thereof are plan views. Two-dot chain lines in FIGS. 7A to 7C indicate areas in which illumination allows good-contrast images to be taken (that is, areas in which good illumination is provided for imaging; hereinafter also referred to as “recommended imaging areas S”).

In the present embodiment, an illumination device 52 of a predetermined size is used. Note that a portion of a subject tool Tx from a base end to a blade edge supported by a pot 22 is referred to as a portion Ta to be imaged as described above. Thus, as illustrated in FIG. 7A, in a case of a subject tool Tx having a certain large size, the portion Ta thereof to be imaged cannot be included within the recommended imaging area S, and a high-contrast image of the entire portion Ta to be imaged cannot be obtained. Thus, a larger illumination device 52 may be used, but this leads to an increase in cost.

The present embodiment therefore employs a method of driving the shutter 30 to open and close and moving the illumination device 52 by the shutting mechanism 32, imaging a subject tool Tx a plurality of times, and recognizing the shape of the entire portion Ta to be imaged on the basis of the images. Hereinafter, a region in each of the images, that is, an image of part of the subject tool Tx will be referred to as a “partial image”. When the illumination device 52 is moved, the imaging processing unit 92 images the subject tool Tx a plurality of times at least before and after the movement or during the movement to obtain a plurality of images.

Specifically, when the shutter 30 is driven in an opening direction (that is, when the shutter 30 is moved in the opening direction by opening operation of the shutting mechanism 32), the camera 50 images a pre-use tool Tp a plurality of times. In addition, when the shutter 30 is driven in a closing direction (that is, when the shutter 30 is moved in the closing direction by closing operation of the shutting mechanism 32), the camera 50 images a used tool Tu a plurality of times. The imaging of a pre-use tool Tp is performed just before tool replacement performed by the ATC 34, and imaging of a used tool Tu is performed just after tool replacement performed by the ATC 34.

Specifically, a pre-use tool Tp is imaged at an opening operation start point of the shutting mechanism 32 (FIG. 7A), and further imaged at an opening operation intermediate point and an opening operation end point of the shutting mechanism 32 (FIGS. 7B and 7C). Note that the “opening operation start point” used herein corresponds to a closed state of the shutter 30, the “opening operation intermediate point” corresponds to an intermediate open state of the shutter 30, and the “opening operation end point” corresponds to a fully-open state of the shutter 30. The “opening operation intermediate point” may be a temporary stop point or a passage point of the illumination device 52. A temporary stop point is preferable for obtaining images with less noise due to a change in illumination. The “opening operation end point” is also a start point of closing movement of the illumination device 52. Note that the exposure time of the camera 50 may be limited, so that imaging can be performed without temporarily stopping the illumination device 52 at an opening operation intermediate point.

In the example of FIGS. 7A to 7C, imaging is performed once at the opening operation start point of the shutting mechanism 32 (FIG. 7A), once at an opening operation intermediate point of the shutting mechanism 32 (FIG. 7B), and further once at the opening operation end point of the shutting mechanism 32 (FIG. 7C). The first image of the three images obtained during opening control of the shutter 30 is a first pre-use image P1, the second image thereof is a second pre-use image P2, and the third image thereof is a third pre-use image P3.

Because the contrast is higher as the illumination device 52 is closer to the front, portions corresponding to the recommended imaging area S differ in different pre-use images. In the first pre-use image P1, a base-end side part of the portion Ta to be imaged is within the recommended imaging area S. In the second pre-use image P2, a middle part of the portion Ta to be imaged is within the recommended imaging area S. In the third pre-use image P3, an edge side part of the portion Ta to be imaged is within the recommended imaging area S. Note that, because the amount by which the illumination device 52 moves from one imaging to another is smaller than the length of the recommended imaging area S, the recommended imaging area S in a pre-use image and the recommended imaging area S in a next pre-use image partially overlap with each other.

FIGS. 8A and 8B are diagrams illustrating an image processing method. FIG. 8A illustrates an image extracting method, and FIG. 8B illustrates an image combining method.
The imaging processing unit 92 extracts a partial image with a relatively high contrast from each of the pre-use images P1 to P3 (FIG. 8A), and combines the extracted partial images to generate a whole image of the subject tool Tx (FIG. 8B).

Specifically, the imaging processing unit 92 extracts a partial image Pb1 within the recommended imaging area S from the first pre-use image P1, extracts a partial image Pb2 within the recommended imaging area S from the second pre-use image P2, and extracts a partial image Pb3 within the recommended imaging area S from the third pre-use image P3 (FIG. 8A). The imaging processing unit 92 then arranges and combines the partial images Pb1 to Pb3 to generate a whole image Pa of the subject tool Tx (FIG. 8B). As a result, the whole image Pa that is a high-contrast and good-quality image can be obtained. The imaging processing unit 92 identifies the outline of the pre-use tool Tp (portion Ta to be imaged) on the basis of the whole image Pa.

Specifically, the silhouette of the subject tool Tx cast by the illumination device 52 is displayed as the whole image Pa of the portion Ta to be imaged. The imaging processing unit 92 sets a scanning line in the X-axis direction, and detects, as an edge point, a point located on a boundary between a dark region (a silhouette region in which the subject tool Tx is present ) and a light region (a region in which the subject tool Tx is not present). The imaging processing unit 92 shifts the scanning line by a constant pitch to detect a plurality of edge points, and connects the edge points to identify the outline of the subject tool Tx. The shape reproducing unit 94 generates tool shape data (pre-use tool shape data) on the basis of the identified outline.

Image processing of a used tool Tu is performed in a manner similar to that of a pre-use tool Tp except that the driving direction of the shutter 30 (that is, the moving direction of the illumination device 52) during imaging is different. The process of imaging a used tool Tu is performed subsequent to a process of tool replacement with a pre-use tool Tp.

Specifically, a used tool Tu is imaged at a closing operation start point of the shutting mechanism 32 (FIG. 7C), and further imaged at a closing operation intermediate point and a closing operation end point of the shutting mechanism 32 (FIGS. 7A and 7B). Note that the “closing operation start point” used herein corresponds to a fully open state of the shutter 30, the “closing operation intermediate point” corresponds to an intermediate closed state of the shutter 30, and the “closing operation end point” corresponds to the closed state of the shutter 30. The “closing operation intermediate point” may be a temporary stop point or a passage point of the illumination device 52. A temporary stop point is preferable for obtaining images with less noise due to a change in illumination. The “closing operation end point” is also a start point of opening movement of the illumination device 52.

Imaging is performed once at the closing operation start point of the shutting mechanism 32 (FIG. 7C), once at a closing operation intermediate point of the shutting mechanism 32 (FIG. 7B), and further once at the closing operation end point of the shutting mechanism 32 (FIG. 7A). The first image of the three images obtained during closing control of the shutter 30 is a first used tool image, the second image thereof is a second used tool image, and the third image thereof is a third used tool image.

Note that the image processing method (the image extracting method and the image combining method) for a used tool Tu is similar to that for a pre-use tool Tp. A high-contrast partial image is extracted from each of the used tool images, the partial images are combined, and a whole image is thus obtained. Detailed explanation thereof is omitted herein. The imaging processing unit 92 identifies the outline of the used tool Tu (portion Ta to be imaged) on the basis of the whole image. The shape reproducing unit 94 generates tool shape data (used tool shape data) on the basis of the identified outline.

The determination processing unit 98 compares the pre-use tool shape data and the used tool shape data of the same tool with each other. The determination processing unit 98 determines that the subject tool Tx has a fracture or the like, that is, that the subject tool Tx is a faulty tool when the similarity between the pre-use tool shape and the used tool shape, or in particular, the similarity in the outline therebetween is a predetermined value or lower. In this case, the informing unit 84 displays, for the user, an alert screen indicating that a faulty tool is detected. Alternatively, the informing unit 84 may produce sound such as buzzer sound.

FIG. 9 is a flowchart illustrating processes of a pre-use tool shape data acquiring process.
This process is triggered by a pre-use tool Tp being held horizontally in a standby state in the storage chamber 10 before tool replacement. At this point, the shutter 30 is in the closed state, and the illumination device 52 is at an opening movement start point.

Prior to this process, the imaging processing unit 92 sets a predetermined tool replacement prohibition flag (S10). This prohibits tool replacement by the ATC 34 during imaging of a pre-use tool Tp. Subsequently, the camera 50 images the pre-use tool Tp (S11). The resulting image is stored as a first pre-use image P1. Subsequently, the movement controlling unit 90 causes the shutting mechanism 32 to operate to move the shutter 30 in the opening direction (S12). When the illumination device 52 has thus reached a next illuminating position (S14: Y), the shutter 30 is temporarily stopped (S16). The imaging processing unit 92 causes the camera 50 to image the pre-use tool Tp (S18). The resulting image is stored as a second pre-use image P2.

The processes of S12 to S18 are repeated until a set number of times of imaging is completed (S20: N). While the set number is three and imaging is completed when a third pre-use image P3 is obtained in the present embodiment, the set number may be changed depending on the tool length. When the set number of times of imaging is completed (S20: Y), the tool replacement prohibition flag is turned off (S22). As a result of the completion of imaging, the tool replacement by the ATC 34 is permitted. In other words, the process of imaging a pre-use tool Tp is performed while the tool replacement prohibition flag is on.

The imaging processing unit 92 extracts high-contrast partial images Pb1 to Pb3 respectively from the pre-use images P1 to P3 describe above (S24), and combines the partial images Pb1 to Pb3 to generate a whole image Pa (S26). The shape reproducing unit 94 generates pre-use tool shape data on the basis of the whole image Pa (S28). The tool managing unit 96 stores the pre-use tool shape data in association with the tool ID in the shape data storage unit 102 (S30). The pre-use tool shape data is used for a tool test, which will be described later.

FIG. 10 is a flowchart illustrating processes of a tool testing process.
This process is triggered by a used tool Tu being held horizontally in a standby state in the storage chamber 10 after tool replacement and before tool storage. At this point, the shutter 30 is in the fully open state, and the illumination device 52 is at a closing movement start point.

The imaging processing unit 92 causes the camera 50 to image the used tool Tu (S40). The resulting image is stored as a first used tool image. Subsequently, the movement controlling unit 90 causes the shutting mechanism 32 to operate to move the shutter 30 in the closing direction (S42). When the illumination device 52 has thus reached a next illuminating position (S44: Y), the shutter 30 is temporarily stopped (S46). The imaging processing unit 92 causes the camera 50 to image used tool Tu (S48). The resulting image is stored as a second used tool image.

The processes of S42 to S48 are repeated until a set number of times of imaging is completed (S50: N). While the set number is three and imaging is completed when a third used tool image is obtained in the present embodiment, the set number may be changed depending on the tool length. When the set number of times of imaging is completed (S50: Y), the imaging processing unit 92 extracts high-contrast partial images respectively from the used tool images described above (S52), and combines the partial images to generate a whole image (S54). The shape reproducing unit 94 generates used tool shape data on the basis of the whole image (S56). The tool managing unit 96 temporarily stores the used tool shape data in the shape data storage unit 102 (S58).

The determination processing unit 98 reads pre-use tool shape data associated with the same tool ID as the used tool shape data (S60), and compares the tool shape data with each other (S62). Specifically, the pre-use tool shape and the used tool shape of the same tool are compared with each other. If the tool is a faulty tool with the similarity between the used tool shape and the pre-use tool shape being a predetermine value or smaller (S64: Y), the informing unit 84 provides information of the same (S66). Specifically, the informing unit 84 causes an alert screen to be displayed. If the tool is not a faulty tool (S64: N), the process of S66 is skipped.

In the present embodiment, a used tool Tu that is determined to be a faulty tool after tool replacement is also stored in the magazine 20, but the tool is prohibited from being used until predetermined maintenance is performed. The information that the tool is prohibited from being used is stored in association with the tool ID.

Typically, for each tool, upper limits of the number of uses and the hours of use (also referred to as “quality assurance parameters”) are determined in order to ensure the quality thereof. Tool with a quality assurance parameter exceeding the upper limit is prohibited from being used, and another tool of the same type (sub-tool) that is additionally provided and stored in the magazine 20 is used. This prevents interruption of a mass production process by the machining equipment 2. In the present embodiment, in a case where a tool is detected as a faulty tool, the tool is managed as being prohibited from being used even when the quality assurance parameters do not exceed the upper limits, and a sub-tool is used.

The machine tool 1 has been described above on the basis of the embodiment.
In the present embodiment, the illumination device 52 is fixed to the shutter 30, and imaging is performed a plurality of times with the illumination device 52 being moved in the longitudinal direction of a subject tool Tx with the opening and closing operation of the shutter 30. Thus, a large and expensive device need not be used as the illumination device 52. Thus, according to the present embodiment, high-contrast images can be obtained regardless the tool length and tool shapes can be detected with sufficient accuracy with reduced cost.

Because the tool testing process is performed while the shutter 30 is in the closed state, another machining can also be performed in the machining equipment 2 during the tool testing process. In other words, image processing can be performed during machining, which is another advantage in that image processing and machining do not interfere with each other.

The present invention is not limited to the embodiment described above and modifications thereof, and any component thereof can be modified and embodied without departing from the scope of the invention. Components described in the embodiment and modifications can be combined as appropriate to form various embodiments. Some components may be omitted from the components presented in the embodiment and modifications.

In the embodiment, an example of the configuration to image a portion Ta to be imaged of a subject tool Tx three times, and combine the resulting images to obtain a high-contrast whole image has been presented. Specifically, the illumination device 52 is moved and the number of times of imaging performed by the camera 50 is more than one regardless of the length of the subject tool Tx. Thus, some times of imaging may be waste for a short subject tool Tx.

In a modification, in a case where a portion Ta to be imaged is as short as being within the recommended imaging area S, the number of times of imaging performed by the camera 50 may be one. Specifically, imaging of a pre-use tool Tp may be performed only once at the opening movement start point of the illumination device 52. Imaging of a used tool Tu may be performed only once at the closing movement end point of the illumination device 52.

Tool length information is stored in association with the tool ID in the tool information storage unit 100. The movement controlling unit 90 reads tool information associated with a subject tool Tx, and when the tool length is equal to or smaller than a first reference value, imaging may be performed only once. The “first reference value” may be the length of the recommended imaging area S or smaller (see FIGS. 7A to 7C).

In addition, in a case where all parts of a portion Ta to be imaged can be included in the recommended imaging area S by two times of imaging, the number of times of imaging may be two. In this case, a pre-use tool Tp may be imaged at the opening movement start point and the opening movement end point of the illumination device 52. In addition, a used tool Tu may be imaged at the closing movement start point and the closing movement end point of the illumination device 52.

Conversely, in a case where a portion Ta to be imaged is so long that a part thereof is not included within the recommended imaging area S by three times of imaging, the number of times of imaging may be more than three. The movement controlling unit 90 may set the number of times the shutter 30 is to be stopped depending on the length of a subject tool Tx (the length of a portion Ta to be imaged). The imaging processing unit 92 may image a subject tool Tx each time the movement of the illumination device 52 is stopped.

In the embodiment, an example of the configuration to temporarily stop the shutter 30 at a movement intermediate point of the illumination device 52, and image a subject tool Tx in a state in which the illumination device 52 is stopped has been presented. In a modification, a subject tool Tx may be imaged with the opening or closing speed of the shutter 30 (that is, the moving speed of the illumination device 52) being lowered at a movement intermediate point of the illumination device 52. In other words, imaging may be performed while the illumination device 52 is moved at a low speed.

In this case, imaging may be performed a plurality of times (a number of times) based on the shutter speed. A plurality of regions (regions 1 to m) may be set in the same manner in each of a plurality of images (images 1 to n), and each of the regions may be obtained as a partial image. A partial image with the highest contrast of partial images included in the images 1 to n may then be extracted for each of the regions 1 to m, and the extracted partial images may be combined to form a whole image.

FIGS. 11A and 11B are diagrams illustrating illumination and imaging methods according to a modification. FIGS. 11A and 11B illustrate processes of imaging. In FIGS. 11A and 11B, one-dot chain lines indicate imaging areas Sp to be imaged by the camera 50, and two-dot chain lines indicate recommended imaging areas S in which high contrast is provided by the illumination device 52.

Although not described in the embodiment, a subject tool Tx includes a holder Th supported by a pot 22, and a blade Tb attached coaxially with holder Th as illustrated in FIG. 11A. The length by which the blade Tb protrudes from the holder Th is referred to as an overhang lo. The camera 50 has such an angle of view that enables the entire subject tool Tx to be captured within the imaging area Sp.

In the present modification, after the shutter 30 has moved by a predetermined distance x1 from the start of movement in the opening direction, the camera 50 performs first imaging of the pre-use tool (FIG. 11A). Thereafter, after the shutter 30 has moved by a predetermined distance x2, the camera 50 performs second imaging. The distance x1 is set so that at least a leading end position of the holder Th (that is, a base end position from which the blade Tb protrudes) is included in the recommended imaging area S. The distance x2 is set to be equal to or larger than a half of the length of a blade part of the subject tool Tx (more specifically, the overhang lo).

In addition, in a manner similar to the embodiment, a partial image corresponding to the recommended imaging area S is obtained from each of the images obtained by the two times of imaging, and the partial images are arranged and combined to generate an image of the blade part and the surroundings thereof. According to the present modification, a high-contrast and good-quality image focusing on the blade part (an exposed portion of the blade Tb) of the subject tool Tx can be obtained.

While an example of a pre-use tool has been presented in the present modification, a good-quality image can be similarly obtained for a used tool. In this case, the camera 50 images a used tool immediately after replacement when the shutter 30 moves in the closing direction. The camera 50 performs first imaging before the shutter 30 starts moving in the closing direction or after the shutter 30 has moved by a predetermined distance in the closing direction. At this point, at least the leading end position of the blade Tb is included in the recommended imaging area S. After performing the first imaging, and after the shutter 30 has moved by more than a half of the length of the blade part of the tool (that is, more than the overhang), the camera 50 performs second imaging.

Then, a partial image corresponding to the recommended imaging area S can be obtained from each of the images obtained by the two times of imaging, and the partial images can be arranged and combined to generate an image of the blade part and the surroundings thereof.

In another modification, first imaging (before-use imaging) may be performed on a pre-use tool before the shutter 30 is opened (before the shutter 30 is moved), and second imaging (after-use imaging) may be performed on a used tool that is the same tool after the tool is replaced and after the shutter 30 is closed. Note that an image obtained by before-use imaging is also referred to as a “pre-use image”, and an image obtained by after-use imaging is also referred to as a “used tool image”. In this case, the presence and absence of a breakage of a subject tool Tx may be detected on the basis of whether or not the tool is included in the used tool image in the same manner as in the pre-use image. Specifically, it may be determined that a breakage is detected when the tool is not included in the same manner. Because the illumination device 52 moves with the shutter 30, adhesion of mist or the like from the machining chamber 8 to the illumination device 52 is reduced.

In the embodiment, an example of the configuration in which the camera 50 is fixed and a subject tool Tx is imaged a plurality of times while the illumination device 52 is moved has been presented. In a modification, a subject tool Tx may be imaged a plurality of times while both the camera 50 and the illumination device 52 are moved. Arrangement of the camera 50 and the illumination device 52 just opposite each other with respect to a subject tool Tx enables a high-quality image with a higher contrast to be obtained. In this case, a moving mechanism for moving the camera 50 along the longitudinal direction of the subject tool Tx is provided.

In the embodiment, an example of the configuration in which the determination processing unit 98 determines a fault of a subject tool Tx has been presented. In a modification, tool shape data of each of a pre-use tool Tp and a used tool Tu generated by the shape reproducing unit 94 may be displayed in drawings by the output unit 82 in such a manner that the shapes can be compared with each other. The user may visually compare the tool shapes before and after use to determine whether or not the subject tool Tx is a faulty tool.

In the embodiment, each subject tool Tx is imaged before and after tool replacement (that is, before and after machining), and tool shape data are generated. The pre-use tool shape data and the used tool shape data of each tool are then compared with each other, and it is determined whether or not an abnormality such as a fracture is present. In a modification, the process of determining a faulty tool may be performed using tool images themselves without generating tool shape data (tool outline data). Specifically, whether or not a used tool Tu is a faulty tool may be determined on the basis of comparison between a pre-use tool image and a used tool image of each subject tool Tx.

In the embodiment, each subject tool Tx is imaged just before and just after machining, and the state of a used tool Tu (whether or not a used tool Tu is a faulty tool) is determined on the basis of the resulting images. In other words, an example in which an image just before use is used as a “reference image” that is a criterion for determination has been presented. In a modification, a reference image may be stored as basic data at registration of a tool before the tool is initially used. For accurate shape detection (shape comparison) in equal imaging environments such as the illumination state, however, comparison between an image just before machining and an image just after machining is preferable.

In the embodiment, an example in which the imaging unit (the camera 50) is located above a subject tool Tx, and the illumination unit (the illumination device 52) is located below the subject tool Tx has been presented. Conversely, in a modification, the imaging unit may be located below the subject tool Tx, and the illumination unit may be located above the subject tool Tx. In terms of preventing the camera lens from being stained, the arrangement of the embodiment is preferable. This is because, when the camera located below a subject tool and the subject tool is a used tool, droplets of coolant may fall from the used tool and stain the lens of the camera. There is no such concern according to the embodiment.

In the embodiment, an example of the configuration in which the pots 22 of the magazine 20 serve as “tool supports” and each pot 22 supports a subject tool Tx in a standby state in the storage chamber 10 has been presented. In a modification, the ATC 34 (more specifically, the arm 38) may function as a “tool support”. Specifically, the illumination unit may be moved by the shutter and imaging may be performed by the imaging unit in a state in which a subject tool before tool replacement or after tool replacement is supported by the ATC.

While the ATC 34 has been presented as an example of a “tool conveying part” in the embodiment, a tool conveying mechanism for conveying tools between the machining chamber and the storage chamber without having the tool replacing function may be provided.

While an example of a machining center as the machine tool 1 has been presented in the embodiment, it is needless to say that the tool testing technology described above is also applicable to turning centers and combined machines.

Claims

A machine tool comprising:
a storage chamber for accommodating a plurality of tools;
a machining chamber for being used for machining with a tool;
a shutter for closing an opening in a partition between the storage chamber and the machining chamber;
a tool support for supporting a tool for replacement in the storage chamber;
an imaging unit located in the storage chamber;
an illumination unit fixed to the shutter, the illumination unit illuminating the tool supported by the tool support; and
a shutting mechanism for moving the shutter along a longitudinal direction of the tool to close the opening,
wherein the illumination unit is integrally moved with the shutter, and the tool is imaged by the imaging unit.
The machine tool according to claim 1, wherein the illumination unit is located opposite the imaging unit with respect to the tool.
The machine tool according to claim 1, wherein when the shutter is moved, the imaging unit images the tool a plurality of times at least one of before and after the movement and during the movement.
The machine tool according to claim 3, further comprising:
a data storage unit for storing images obtained by imaging; and
an imaging processing unit for performing a predetermined process on the basis of the images,
wherein the imaging processing unit extracts a partial image with a relatively high contrast from each of the images obtained by imaging one tool a plurality of times, and combines the extracted partial images to generate a whole image of the tool.
The machine tool according to claim 3,
wherein the imaging unit performs imaging of a pre-use tool immediately before replacement when the shutter moves in an opening direction, and
wherein after performing first imaging, the imaging unit performs second imaging after the shutter has moved by a distance of a half or more of a length of a blade part of the tool.
The machine tool according to claim 5, wherein the imaging unit performs the first imaging after the shutter has started to move and has moved by a predetermined distance.
The machine tool according to claim 3, wherein the imaging unit performs a plurality of times of imaging of a used tool immediately after replacement when the shutter moves in a closing direction.
The machine tool according to claim 7, further comprising:
a determination processing unit for performing a predetermined determination process on the basis of images obtained by imaging,
wherein the determination processing unit determines a state of the used tool on the basis of an image of the used tool and a reference image of a tool being the same tool as the used tool, the reference image being obtained in advance.
The machine tool according to claim 3, further comprising:
a determination processing unit for performing a predetermined determination process on the basis of images obtained by imaging,
wherein the imaging unit performs a plurality of times of imaging of a pre-use tool immediately before replacement when the shutter moves in an opening direction, and a plurality of times of imaging of a used tool immediately after replacement when the shutter moves in a closing direction, and
wherein the determination processing unit determines a state of the used tool on the basis of an image of the used tool and an image of the pre-use tool, the pre-use tool being the same tool as the used tool.
A machine tool comprising:
a storage chamber for accommodating a plurality of tools;
a machining chamber for being used for machining with a tool;
a shutter for closing an opening in a partition between the storage chamber and the machining chamber;
a tool support for supporting a tool for replacement in the storage chamber;
an imaging unit located in the storage chamber;
an illumination unit fixed to the shutter, the illumination unit illuminating the tool supported by the tool support; and
a shutting mechanism for moving the shutter along a longitudinal direction of the tool to close the opening.