WO2023079614A1

WO2023079614A1 - Seating determination device and machine tool

Info

Publication number: WO2023079614A1
Application number: PCT/JP2021/040558
Authority: WO
Inventors: 淳平松村; 淳 ▲柳▼▲崎▼; 信也熊▲崎▼
Original assignee: 株式会社Fuji
Priority date: 2021-11-04
Filing date: 2021-11-04
Publication date: 2023-05-11
Also published as: JPWO2023079614A1

Abstract

According to the present invention, a seating determination device comprises a detection device that detects a physical quantity that varies in accordance with the seating state of a workpiece, a determination unit that determines the seating state on the basis of the physical quantity and a threshold value set for the physical quantity to determine the seating state during processing of the workpiece, and a setting unit that sets the threshold value for each different process performed on the workpiece.

Description

Seating determination device and machine tool

This specification relates to a seating determination device and a machine tool.

Conventionally, for example, the seating determination method disclosed in Patent Document 1 below has been disclosed. In the conventional seating determination method, when the back pressure detected by the pressure sensor during machining converges within a predetermined pressure range within the set time and becomes constant, the back pressure that becomes constant by the control device is used as the reference. is used to set the threshold for processing. In the conventional seating determination method, the control device compares the back pressure threshold value for machining with the back pressure detected by the pressure sensor to make a pass/fail determination.

JP 2017-7027 A

By the way, when machining a seated work, the seating state of the work may change depending on the machining. Therefore, it is necessary to determine the seating state by setting an appropriate threshold value for each different processing. However, in the above-described conventional seating determination method, when setting the threshold value for processing, setting the threshold value for processing for each different processing is not disclosed.

The purpose of this specification is to provide a seating determination device that can monitor the seating state of a workpiece for each different machining.

The present specification describes a detection device that detects a physical quantity that changes according to the seating state of a workpiece, and a seating state based on the physical quantity and a threshold value set for the physical quantity for determining the seating state during machining of the workpiece. and a setting unit for setting a threshold value for each different machining of a workpiece.

According to the seating determination device, the threshold can be set for each different processing by the setting unit. Therefore, the seating determination device can constantly and finely monitor the seating state for each different machining, and as a result, the accuracy of machining the workpiece can be improved.

1 is a side view for explaining the configuration of a machine tool provided with a seating determination device; FIG. 2 is a partial cross-sectional view for explaining the configuration of a detection device of the seating determination device of FIG. 1; FIG. 2 is a functional block diagram for explaining the configuration of a control device of the seating determination device of FIG. 1; FIG. FIG. 4 is a diagram for explaining input of a threshold value for each processing in the control device of FIG. 3; FIG. 10 is a diagram for explaining threshold values set for each different processing (each processing content); It is a figure for demonstrating the threshold value set for every different process. FIG. 11 is a partial cross-sectional view for explaining the configuration of a detection device of the seating determination device of the first modified example; FIG. 11 is a functional block diagram for explaining the configuration of a control device of the seating determination device of the first modified example; It is a figure for demonstrating a physical quantity.

The seating determination device and machine tool will be described below with reference to the drawings. In this embodiment, a machining system including an automatic work transfer machine that transfers a work to a machine tool having a seating determination device will be described as an example.

1. Overall Configuration of Machining System 10 As shown in FIG. 1, the machining system 10 includes a base 20 and a machine tool 30 that is provided on the base 20 and performs various types of machining on the workpiece W. As shown in FIG. In this embodiment, the case where one machine tool 30 is provided on the base 20 is exemplified, but it is also possible to provide a plurality of machine tools 30 on the base 20 . Further, the machining system 10 includes an articulated robot 50 (hereinafter simply referred to as "robot 50” in some cases). Further, the machine tool 30 that constitutes the machining system 10 is provided with a seating determination device 60 that determines the seating state of the workpiece W carried in by the robot 50 .

2. machine tool 30
The machine tool 30 rotates or non-rotatably fixes a workpiece W, which is an object to be machined, and performs different machining such as cutting and boring (drilling). The machine tool 30, as shown in FIG. The movable head 41 moves along the Z-axis direction (front-rear direction) on rails (not shown) provided on the base 20 via a plurality of wheels 41a.

The headstock 42 holds the workpiece W rotatably. The headstock 42 rotatably supports a main spindle 42a arranged horizontally along the Z-axis direction (front-rear direction). A chuck 42c for holding the work W is provided on a seating portion 42b (so-called contact metal) for the work W provided at the tip of the spindle 42a. A detection device 61 of a seating determination device 60, which will be described later, is arranged behind the seating portion 42b in the Z-axis direction. The main shaft 42a is rotatably driven by a servomotor 42e via a rotation transmission mechanism 42d, and is rotatable around the Z-axis.

The tool table 43 is a device that holds a plurality of tools 43a and feeds the selected tool 43a. The tool rest 43 is a polygonal turret-type tool rest (tool rest), and has a tool holder 43b to which a plurality of tools 43a for machining the workpiece W are attached. Here, as the tool 43a, a cutting tool such as a cutting tool or a rotary tool such as an end mill or a drill can be exemplified.

Further, the tool table 43 has a rotary drive section 43c capable of rotatably supporting the tool holding section 43b and fixing the indexed tool 43a, that is, the tool holding section 43b. As a result, in the tool table 43, the tool holding portion 43b is rotated by rotating the rotation driving portion 43c, and the tool 43a corresponding to each machining of the workpiece W is selected by turning indexing.

The tool table moving device 44 is a device that moves the tool table 43 and thus the tool 43a along the X-axis direction (vertical direction) and the Z-axis direction (front-rear direction). The tool rest moving device 44 has an X-axis driving device 44a for moving the tool rest 43 along the X-axis direction and a Z-axis driving device 44b for moving the tool rest 43 along the Z-axis direction.

The X-axis drive device 44a includes an X-axis slider 44a1 slidably attached to a column provided on the movable head 41 along the vertical direction, and a servo motor 44a2 for moving the X-axis slider 44a1. have. The Z-axis driving device 44b has a Z-axis slider 44b1 slidably attached to the X-axis slider 44a1 along the front-rear direction, and a servo motor 44b2 for moving the Z-axis slider 44b1. .

The machining chamber 45 is a space for machining the workpiece W, and accommodates a chuck 42c and a tool table 43 (a tool 43a, a tool holding portion 43b, a rotation driving portion 43c, and a detection device 61). ing. The processing chamber 45 is partitioned by a front wall 45a, a ceiling wall 45b, left and right walls, and a rear wall (all not shown). The front wall 45a is formed with an inlet/outlet 45a1 through which the work W is entered/exited. The inlet/outlet 45a1 is opened and closed by a shutter 45c driven by a motor (not shown). The open state (open position) of the shutter 45c is indicated by a solid line, and the closed state (closed position) is indicated by a chain double-dashed line.

The traveling chamber 46 is a space provided facing the inlet/outlet 45a1 of the processing chamber 45. The traveling room 46 is defined by the front wall 45 a and the front panel 31 . A robot 50 , which will be described later, can run in the running room 46 .

The control device 47 includes, for example, a CNC (Computer Numerically Controlled), a PLC (Programmable Logic Controller), a servo system, etc. as main components, and a rotary drive unit 43c of the machine tool 30, a tool It controls the operation of the stage moving device 44 and the like. In this embodiment, the control device 47 is communicably connected to a setting device 62 of a seating determination device 60, which will be described later.

3. robot 50
The robot 50 is movable, and loads a workpiece W before machining into the machine tool 30 and unloads the workpiece W after machining from the machine tool 30 . Therefore, the robot 50 has a traveling portion 51 , a body portion 52 and a robot hand 53 .

The running section 51 runs inside the running chamber 46 . The body portion 52 has a turning table and an arm portion, and by turning and expanding and contracting the arm portion, the workpiece W is carried into and out of the processing chamber 45, more specifically, the main shaft 42a. The robot hand 53 is provided at the tip of the arm portion of the body portion 52, and grips (clamps) the work W and releases (unclamps) the work W. As shown in FIG.

4. Seating determination device 60
As shown in FIG. 1, the seating determination device 60 includes a headstock 42, more specifically, a detection device 61 provided behind the seating portion 42b of the spindle 42a, and a setting device 62 provided below the control device 47. and In this embodiment, the setting device 62 is arranged below the control device 47, but the arrangement of the setting device 62 is not limited to this, and it goes without saying that the setting device 62 can be arranged at a position spaced apart from the control device 47. stomach.

4-1. detection device 61
The detection device 61 includes a detection hole 611, an air supply pipe 612 and a digital seating sensor 613, as shown in FIG. A plurality of detection holes 611 are provided in the seating portion 42b. For example, a plurality of detection holes 611 are arranged at equal intervals on the circumference. The detection hole 611 is such that the detection hole 611 opened on the seating surface 42b1 is blocked by the back surface W1 of the workpiece W to a certain extent when the workpiece W is properly seated on the seating surface 42b1 of the seating portion 42b. ing.

The air supply pipe 612 connects the detection hole 611 and an air supply source C such as a compressor installed in the factory. A flow control valve Va is connected to the air supply pipe 612 so as to adjust the throttle amount of the flow path. A pressure gauge G for detecting the primary side pressure supplied from the air supply source C is connected to the primary side (air supply source C side) of the flow control valve Va in the air supply pipe 612 .

The digital seating sensor 613 is connected to the secondary side of the flow control valve Va (the seating portion 42b side of the main shaft 42a). A digital seat sensor 613 is formed including a back pressure gauge 614 and a pressure switch 615 . The back pressure gauge 614 detects the back pressure P (see FIG. 3), which is the pressure of the positive air that is ejected from the detection hole 611 on the seating surface 42b1 and supplied toward the back surface W1 of the workpiece W. The back pressure gauge 614 then outputs a digital signal representing the detected back pressure P. FIG.

By the way, the back pressure P detected by the back pressure gauge 614 corresponds to the seating state in which the work W is attached to the seating portion 42b, that is, the back surface W1 of the work W is seated facing the seating surface 42b1. is a physical quantity that varies with Here, as the sitting state of the work W, for example, a sitting state in which the back surface W1 and the seating surface 42b1 are parallel and close to each other can be cited as an appropriate sitting state. In an appropriate seated state, the detection hole 611 is blocked by the back surface W1, so the detected back pressure P increases.

On the other hand, as the seating state of the workpiece W, for example, a state in which the back surface W1 is inclined with respect to the seating surface 42b1, or a state in which the distance between the back surface W1 and the seating surface 42b1 is large, can be cited as an inappropriate seating state. can. In an inappropriate seating state, in other words, in a floating state in which the back surface W1 of the workpiece W is lifted from the seating surface 42b1 of the seating portion 42b, all or part of the detection hole 611 is not blocked by the back surface W1, so that detection is not possible. back pressure P becomes smaller.

The pressure switch 615 is a solid state digital pressure switch and is connected to the setting device 62 and the control device 47 . As will be described later, the pressure switch 615 has threshold values LV1, LV2, . It outputs a signal Sn or an abnormal signal Sa (see FIG. 3). Here, in this embodiment, the pressure switch 615 functions as a determination section and an output section.

The pressure switch 615 compares the detected back pressure P with threshold values LV1, LV2, . Then, the pressure switch 615 outputs a normal signal Sn representing an appropriate seating state when the back pressure P is equal to or greater than threshold values LV1, LV2, . do. On the other hand, when the back pressure P is less than the threshold values LV1, LV2, . An abnormal signal Sa representing is output. Here, the pressure switch 615 as a determination unit detects an abnormality when, for example, the detected back pressure P continues to be less than the threshold values LV1, LV2, . A signal Sa can be output.

4-2. Setting device 62
The setting device 62 has, for example, a PLC as a main component, and can communicate with the control device 47 . Here, in this embodiment, as shown in FIG. 3, the setting device 62 acquires the processing information J for each different processing from the control device 47 by communication. The machining information J is information set for each machining (each machining content), and is related to, for example, machining of the workpiece W by the tool 43a, and includes the machining position of the tool 43a with respect to the workpiece W, the machining direction, the machining speed, This information includes the amount of machining per unit time (for example, cutting volume per unit time). The machining information J can be extracted from, for example, an NC program stored in the control device 47 .

The setting device 62 includes an input section 621, a setting section 622 and a history storage section 623, as shown in FIG. The setting device 62 is operated by an operator who works using the machine tool 30 .

The input unit 621 is a human interface operated by the operator. The input unit 621 inputs the threshold values LV1, LV2, . Input of the thresholds LV1, LV2, . . . , LVn and the reference threshold LVb will be described below. In the description, the thresholds LV1, LV2, .

The input unit 621 displays a display screen 621a visually recognized by the operator, as shown in FIG. On the display screen 621a, "work No." for identifying the work W to be machined is displayed, and the back pressure P currently detected by the back pressure gauge 614 is displayed as a "detected value". Furthermore, on the display screen 621a, a selection section 621b for selecting (or directly inputting) "processing (processing content)" and a selection section 621c for selecting (or directly inputting) "threshold" are displayed. be.

Here, for the "processing (processing details)", based on the processing information J, the "processing No." be. As for the "threshold", the numerical value is increased or decreased by operating the "+" or "-" using the selection unit 621c.

The display screen 621a can display a "detection value history" that displays the history of the back pressure P acquired from the digital seating sensor 613 as an item stored in the history storage unit 623, which will be described later. Further, on the display screen 621a, it is possible to display "NG count" indicating the number of times the abnormal signal Sa was obtained in the past as an item stored in the history storage unit 623, which will be described later.

Further, on the display screen 621a, as an item stored in a history storage unit 623, which will be described later, "total number of detections" indicating the total number of times the digital seating sensor 613 has detected the back pressure P in the past can be displayed. can. Furthermore, on the display screen 621a, it is possible to display the "NG rate" that can be calculated by dividing the "NG count" by the "total detection count".

Returning to FIG. 3 again, the setting unit 622 sets each threshold LV and the reference threshold LVb input by the input unit 621 to the pressure switch 615 . Here, the setting unit 622 can set the pressure switch 615 by describing each threshold value LV and the reference threshold value LVb as an NC program using M code, for example.

Specifically, for example, in the NC program, the setting unit 622 describes each threshold LV (or reference threshold LVb) between a start code and an end code identifiable for each machining (each machining content). Then, the setting unit 622 sets the threshold LV and the reference threshold LVb by outputting the generated NC program to the pressure switch 615 . Thereby, the pressure switch 615 can sequentially change the threshold value LV according to the machining for each machining according to the NC program.

The setting unit 622 can also set the pressure switch 615 by collectively transmitting all the threshold values LV and the reference threshold values LVb input by the input unit 621 . In this case, the pressure switch 615 can change the threshold value LV (or the reference threshold value LVb) for each processing (for each processing content) by referring to the processing information J acquired from the control device 47, for example.

The history storage unit 623 sequentially stores the back pressure P, the normal signal Sn, and the abnormal signal Sa, which are digital signals acquired from the digital seating sensor 613, in an updatable manner. Then, the history storage unit 623 acquires the detected value of the back pressure P stored renewably, the number of times the back pressure P is acquired, that is, the total number of detections, the number of times the abnormality signal Sa is acquired, and the abnormality signal Sa for the total number of detections. It outputs the ratio of the number of times it has been performed to the input unit 621 .

4-3. Operation of Seating Determination Device 60 The seating determination device 60 can set a threshold value LV for each different processing (or for each different processing content), and the set threshold value LV or a preset reference threshold value LVb can be set. is used to determine the seating state of the workpiece W on the seating portion 42b. By the way, the back pressure P detected by the digital seating sensor 613 is likely to change depending on the machining performed by the machine tool 30, and more specifically, depending on the contents of the workpiece W being machined.

Here, the elements (parameters) that determine different machining (or different machining details) include the machining position, which is the position at which machining is performed on the workpiece W, the machining direction, which is the direction in which machining is performed, and the speed at which machining is performed. , and the amount of machining, which is the amount of machining (for example, the feed amount of the tool 43a, the volume to be removed, etc.). Therefore, when setting the threshold value LV for each different machining, it is necessary to set according to the tendency of change in the back pressure P corresponding to each machining content.

In the following description, as shown in FIG. 5, the position where the tool 43a processes the work W on the front end side is defined as a first processing position A1, and the position where the tool 43a processes the work W on the base end side is defined as a first processing position A1. The second machining position is A2. Also, as shown in FIG. 5, the separation direction in which the tool 43a moves away from the seating surface 42b1 of the seating portion 42b is defined as the first machining direction D1, and the seating direction in which the tool 43a approaches the seating surface 42b1 is the second machining direction D2. and Further, as shown in FIG. 5, the speed at which the tool 43a processes the workpiece W is defined as a machining speed V, and the feed amount of the tool 43a with respect to the workpiece W is defined as a machining amount R. As shown in FIG.

4-3-1. Case Where Machining Positions Are Different For example, it is assumed that the workpiece W is subjected to cutting in the machine tool 30 . In this case, as shown in FIG. 5, when the tool 43a (for example, cutting tool) cuts the workpiece W at the first machining position A1, the back surface W1 tends to tilt with respect to the seating surface 42b1. Therefore, in this case, the workpiece W tends to float, and the detected back pressure P greatly decreases. Therefore, in the machining (machining content) where the machining position is the first machining position A1, it is necessary to set the threshold LV to a value smaller than the reference threshold LVb, for example, in order to accurately determine the seating state of the workpiece W. There is

On the other hand, when the tool 43a cuts the workpiece W at the second machining position A2 on the base end side, the inclination of the back surface W1 with respect to the seating surface 42b1 becomes smaller than in the case of the first machining position A1. Therefore, in this case, the workpiece W is less likely to float, and the decrease in the detected back pressure P is small. Therefore, in the machining (machining content) where the machining position is the second machining position A2, in order to accurately determine the seating state of the workpiece W, for example, it is necessary to set the threshold LV to a value larger than the reference threshold LVb. There is

4-3-2. When Machining Directions Are Different For example, as shown in FIG. It becomes easier to move in the seat separation direction away from. Therefore, in this case, the workpiece W tends to float, and the detected back pressure P greatly decreases. Therefore, in the machining (machining content) in which the machining direction matches the first machining direction D1, the threshold LV is set to a value smaller than the reference threshold LVb, for example, in order to accurately determine the seating state of the workpiece W. There is a need.

On the other hand, when the tool 43a cuts the work W along the second machining direction D2, the work W tends to move toward the seating surface 42b1 of the seating portion 42b, as indicated by the dashed-dotted arrow. Therefore, in this case, the workpiece W is less likely to float, and the decrease in the detected back pressure P is small. Therefore, in the machining (machining content) in which the machining direction matches the second machining direction D2, the threshold LV is set to a value larger than the reference threshold LVb, for example, in order to accurately determine the seating state of the workpiece W. There is a need.

4-3-3. When Machining Speeds are Different For example, as shown in FIG. 5, when the tool 43a cuts the work W along the first machining direction D1, the higher the machining speed V, the greater the friction between the work W and the tool 43a. As a result, the workpiece W can be easily moved in the direction of detaching, as indicated by the dashed arrow. Therefore, as the machining speed V increases, the workpiece W is more likely to float, and the detected back pressure P decreases more. For this reason, in the case of the first machining direction D1, the higher the machining speed V (machining content), the more accurately the seating state of the workpiece W is determined. Must be set to a value.

On the other hand, when the tool 43a cuts the workpiece W along the second machining direction D2, the higher the machining speed V, the easier it is for the workpiece W to move in the seating direction, as indicated by the dashed-dotted arrow. Therefore, in this case, the workpiece W is less likely to float, and the decrease in the detected back pressure P is small. For this reason, in the case of the second machining direction, the larger the machining speed V (the machining content), the more accurately the seating state of the workpiece W is determined. must be set to

4-3-4. When the processing amount differs For example, as shown in FIG. 5, when the tool 43a cuts the work W along the first processing direction D1, the greater the processing amount R, the greater the friction between the work W and the tool 43a. As a result, the workpiece W can be easily moved in the direction of detaching, as indicated by the dashed arrow. Therefore, as the machining amount R increases, the workpiece W is more likely to be lifted, and the decrease in the detected back pressure P increases. Therefore, in the case of the first machining direction D1, the larger the machining amount R (machining content), the more accurately the seating state of the workpiece W is determined. Must be set to a value.

On the other hand, when the tool 43a cuts the workpiece W along the second machining direction D2, the larger the machining amount R, the easier it is for the workpiece W to move in the seating direction, as indicated by the dashed-dotted arrow. Therefore, in this case, the workpiece W is less likely to float, and the decrease in the detected back pressure P is small. Therefore, in the case of the second machining direction, the larger the machining amount R (machining content), the more accurately the seating state of the workpiece W is determined. must be set to

4-3-5. Cases of Different Machining For example, it is assumed that the machine tool 30 performs the cutting shown in FIG. 5 and the drilling shown in FIG. In the case of drilling, the machining direction by the tool 43a (for example, a drill bit) coincides with the second machining direction D2 in which the tool 43a approaches the seating surface 42b1, that is, the seating direction. Therefore, when comparing the case where the machining directions of cutting and drilling are both in the second machining direction D2, the force with which the tool 43a presses the workpiece W in the seating direction is relatively larger in the drilling. Become.

That is, when the tool 43a drills the workpiece W, the workpiece W moves more easily in the seating direction than in the case of cutting, as indicated by the dashed-dotted arrow in FIG. Therefore, in the case of drilling, compared to cutting, the workpiece W is less likely to float, and the decrease in the detected back pressure P is smaller. Therefore, when the machining direction is the same, in drilling, it is necessary to set a value larger than each threshold value LV set according to different machining contents (parameters) of the above-described cutting.

As described above, according to the tendency of the threshold value LV to be set for each different processing (each different processing content), the operator operates the input unit 621 of the setting device 62, and for each different processing (each different processing content) Set the threshold LV. That is, on the display screen 621a of the input unit 621, the operator first selects "processing (processing details)" using the selection unit 621b. Subsequently, the operator uses the selection unit 621c to input an appropriate threshold value LV for the target processing (processing content). Accordingly, the operator inputs respective threshold values LV1, LV2, .

Then, the input unit 621 outputs the input thresholds LV1, LV2, . . . , LVn to the setting unit 622. Here, the operator can input the reference threshold value LVb, which is used as a reference in all processes, using the selection unit 621c, for example. Note that the reference threshold value LVb may be set in the pressure switch 615 in advance.

The setting unit 622 acquires the threshold values LV1, LV2, . . . , LVn and the reference threshold value LVb from the input unit 621. Then, the setting unit 622 sets the threshold values LV1, LV2, .

Accordingly, in the detecting device 61, when the workpiece W is mounted on the seating surface 42b1 of the seating portion 42b of the machine tool 30, the back pressure gauge 614 starts detecting the back pressure P. In the detection device 61, the pressure switch 615 compares the back pressure P with thresholds LV1, LV2, .

Then, the pressure switch 615 outputs a normal signal Sn as a digital signal to the control device 47 and the history storage unit 623 when the detected back pressure P is equal to or higher than the set threshold value LV. As a result, the control device 47 continues machining the work W because the work W is properly seated on the seating surface 42b1 of the seating portion 42b. Also, the history storage unit 623 stores the output normal signal Sn in an updatable manner.

On the other hand, the pressure switch 615 outputs an abnormality signal Sa as a digital signal to the control device 47 and the history storage unit 623 when the detected back pressure P is less than the set threshold value LV. As a result, the control device 47 stops machining the work W because the work W is in a floating state when the work W is seated on the seating surface 42b1 of the seating portion 42b. Also, the history storage unit 623 stores the output normal signal Sn in an updatable manner.

As can be understood from the above description, the seating determination device 60 includes a detection device 61 that detects the back pressure P as a physical quantity that changes according to the seating state of the work W, the back pressure P, and the A pressure switch 615 as a determination unit for determining the seating state based on threshold values LV1, LV2, . and a setting unit 622 for setting threshold values LV1, LV2, . . . , LVn.

Thus, in the seating determination device 60, the setting unit 622 can set the threshold values LV1, LV2, . Therefore, in the seating determination device 60, the seating state, that is, the floating state of the work W can be constantly and finely monitored for each processing (each processing content), and as a result, the processing accuracy of the work W can be improved. can.

Further, in the seating determination device 60, threshold values LV1, LV2, . . . , LVn can be set for each process (each process content). Therefore, for example, compared to the case where only one reference threshold value LVb can be set for the entire machining, when the seating determination device 60 is provided in the machine tool 30, the frequency of stopping machining due to an abnormality in the seating state can be reduced. As a result, the productivity of the work W by the machine tool 30 can be improved.

5. Modification 5-1. First Modification In the embodiment described above, the pressure switch 615 forming the digital seating sensor 613 compares the set threshold value LV with the detected back pressure P, and determines if the back pressure P is less than the threshold value LV. The abnormality signal Sa is output to the control device 47 in some cases. That is, in the above-described embodiment, the pressure switch 615 has the functions of the determination section and the output section.

Alternatively, as shown in FIGS. 7 and 8, the setting device 62 compares the set threshold value LV with the detected back pressure P, and determines if the back pressure P is less than the threshold value LV. It is also possible to output an abnormal signal Sa. The first modified example will be described below, but the same reference numerals will be given to the same parts as in the above-described embodiment, and the description thereof will be omitted.

In the first modification, as shown in FIG. 7, the pressure switch 615 of the digital seating sensor 613 is omitted, and the back pressure P (digital signal) detected by the back pressure gauge 614 is output to the setting device 62. Transformed. In the first modified example, an acquisition unit 624, a determination unit 625, and an output unit 626 are newly provided for the setting device 62, as shown in FIG. The acquisition unit 624 acquires the back pressure P (digital signal) detected from the back pressure gauge 614 and outputs the acquired back pressure P to the determination unit 625 .

, LVn for determination and a reference threshold LVb are set by the setting unit 622. Also in this case, similarly to the embodiment described above, it is possible to describe and set the threshold LV (reference threshold LVb) between the start code and the end code using the M code. The determination unit 625 compares the threshold values LV1, LV2, . . . , LVn and the reference threshold value LVb with the back pressure P acquired by the acquisition unit 624.

Then, the determination unit 625 outputs a normal signal Sn to the output unit 626 when the back pressure P is equal to or higher than each of the thresholds LV1, LV2, . . . , LVn and the reference threshold LVb. , LVn and the reference threshold value LVb, the abnormality signal Sa is output to the output unit 626 . The determination unit 625 also outputs the back pressure P acquired by the acquisition unit 624 to the output unit 626 .

The output unit 626 acquires the normal signal Sn, the abnormal signal Sa, and the back pressure P output from the determination unit 625 . The output unit 626 then outputs the acquired normal signal Sn or abnormal signal Sa to the control device 47 and outputs the back pressure P to the history storage unit 623 .

Therefore, also in the first modified example, threshold values LV1, LV2, . In the first modification, the determination unit 625 compares the back pressure P with each of the threshold values LV1, LV2, . It can be output to the control device 47 via the output unit 626 . Therefore, even in the first modified example, the same effects as in the above-described embodiment can be obtained.

5-2. Second Modification In the embodiment described above, the digital seating sensor 613 outputs the normal signal Sn or the abnormal signal Sa to the control device 47 . Further, in the first modified example described above, the setting device 62 outputs the normal signal Sn or the abnormal signal Sa to the control device 47 . Then, when the control device 47 acquires the abnormality signal Sa, since an abnormality has occurred in the seating state of the work W, the machining is stopped.

By the way, the control device 47 provided in the machine tool 30 has a CNC, a PLC, a servo system, etc. as main components, and operates the rotation drive part 43c, the tool table moving device 44, etc. according to the NC program etc. set for each machining. can be controlled. Therefore, the control device 47 can include the setting device 62 of the embodiment described above, or the setting device 62 of the first modified example described above.

In this case, the control device 47 can include an input section 621, a setting section 622, and a history storage section 623, similar to the setting device 62 of the embodiment described above. As a result, the control device 47 can set the threshold value LV for determination in the pressure switch 615 of the digital seating sensor 613 for each process (each process content). Then, when the controller 47 acquires the abnormality signal Sa from the pressure switch 615, it is possible to stop the machining because there is an abnormality in the seating state of the workpiece W. Therefore, even in this case, the same effects as in the above-described embodiment can be obtained.

In addition to the input unit 621, the setting unit 622, and the history storage unit 623, the control device 47 includes an acquisition unit 624, a determination unit 625, and an output unit 626, similarly to the setting device 62 of the first modified example described above. be able to. However, the control device 47 can omit the output unit 626 as necessary.

As a result, the control device 47 can set the determination threshold value LV for each process (each process content) in the determination unit 625 . Then, the control device 47 compares the back pressure P acquired by the determination unit 625 from the back pressure gauge 614 with the threshold value LV (or the reference threshold value LVb) set for each different processing (each different processing content) and makes a determination. Accordingly, when the abnormality signal Sa is acquired, it is possible to stop the machining because an abnormality has occurred in the seating state of the workpiece W. Therefore, even in this case, the same effects as in the above-described embodiment can be obtained.

5-3. Third Modification In the above-described embodiment, first modification, and second modification, the physical quantity that changes according to the seating state of the work W is the pressure of the positive air supplied toward the back surface W1 of the work W. A certain back pressure P was used. However, the physical quantity is not limited to using the back pressure P as long as it changes according to the seating state of the workpiece W. For example, as shown in FIG. 9, the load K applied to the workpiece W by a machining tool 43a or the distance L between the workpiece W and the seating surface 42b1 can be used. Alternatively, the machining amount R (see FIG. 5) per unit time can be used.

5-4. Fourth Modification In the embodiment and each modification described above, the pressure switch 615 and the determination unit 625 as determination units determine the seating state of the workpiece W based on changes in the back pressure P. FIG. By the way, as described above, the back pressure P detected by the back pressure gauge 614 changes depending on the seating state of the work W, that is, the floating state.

The floating state of the workpiece W depends on the magnitude of the machining load generated when the tool 43a performs machining on the workpiece W, the magnitude of the gripping force with which the chuck 42c grips the workpiece W during machining, and the workpiece W varies depending on at least one of the anomalies of the tool 43a machining the . That is, the back pressure P is the magnitude of the machining load generated when the tool 43a performs machining on the workpiece W, the magnitude of the gripping force with which the chuck 42c grips the workpiece W during machining, and the It changes depending on at least one of the abnormalities of the tool 43a for processing.

Therefore, the pressure switch 615 and the determination unit 625 determine the magnitude of the machining load on the workpiece W by the tool 43a and the magnitude of the gripping force of the workpiece W by the chuck 42c based on the change in the back pressure P detected by the back pressure gauge 614. It is possible to determine at least one of an abnormality such as chipping or breakage of the tool 43a. When the workpiece W is machined, the pressure switch 615 and the determination unit 625 can output an abnormal signal Sa when, for example, it is determined that the machining load is greater than the reference machining load based on the change in the back pressure P. can.

Further, when the workpiece W is processed, the pressure switch 615 and the determination unit 625 output an abnormality signal Sa when determining, for example, that the magnitude of the gripping force is smaller than the reference gripping force based on the change in the back pressure P. can do. Further, when the workpiece W is machined, the pressure switch 615 and the determination unit 625 determine, for example, that the machining amount R is smaller than the reference machining amount based on the change in the back pressure P, the tool 43a is abnormal. is likely to occur, the abnormality signal Sa can be output. Then, in the machine tool 30, the machining of the workpiece W can be stopped along with the acquisition of the abnormality signal Sa.

DESCRIPTION OF SYMBOLS 10... Machining system 20... Base 30... Machine tool 42... Headstock 42a... Spindle 42b... Seating part 42b1... Seating surface 42b1, 43a... Tool, 47... Control device, 50... Articulated robot, 60 Seating determination device 61 Detecting device 611 Detection hole 612 Air supply pipe 613 Digital seating sensor 614 Back pressure gauge 615 Pressure switch (determination section, output section) 62 Setting device 621 Input unit 622 Setting unit 623 History storage unit 624 Acquisition unit 625 Determination unit 626 Output unit LV1, LV2, LVn Threshold, LVb Reference threshold Sn Normal signal Sn , Sa... Error signal, A1... First machining position, A2... Second machining position, D1... First machining direction, D2... Second machining direction, V... Machining speed, W... Work, W1... Back side, P... Back side pressure (physical quantity), K... load (physical quantity), L... distance (physical quantity), R... processing amount (physical quantity)

Claims

a detection device that detects a physical quantity that changes according to the seating state of the workpiece;
a determination unit that determines the seating state based on the physical quantity and a threshold value set for the physical quantity for determining the seating state during machining of the workpiece;
a setting unit that sets the threshold for each different machining of the workpiece;
A seating determination device.
2. The seating determination device according to claim 1, further comprising an output section that outputs an abnormality signal representing an abnormality that has occurred in the seating state when the determination section determines that an abnormality has occurred in the seating state.
The determination unit is provided in the detection device,
3. The seating determination device according to claim 1, wherein said setting unit sets said threshold in said detection device.
The physical quantity is the pressure applied to the work during machining, the load applied to the work by a tool for machining, the distance between the work and the seating surface, and the amount of machining per unit time. The seating determination device according to any one of claims 1 to 3, comprising at least one.
The seating determination device according to any one of claims 1 to 4, wherein the detection device has a digital seating sensor that outputs a digital signal.
Equipped with the seating determination device according to any one of claims 1 to 5,
A machine tool for machining the workpiece seated on the seating portion.
The detection device is provided on the seating portion,
7. The machine tool according to claim 6, wherein said determination unit and said setting unit are provided in a control device that inputs said physical quantity from said detection device and uses said input physical quantity to control the operation of said machine tool.
8. The determination unit according to claim 7, wherein the determination unit determines the seating state of the work on the seating unit by comparing the physical quantity detected by the detection device and the threshold value set by the setting unit. Machine Tools.
The machine tool according to claim 7 or 8, wherein the control device stops machining the workpiece when an abnormality occurs in the seating state.
The setting unit sets the threshold based on at least one of a machining position, a machining direction, a machining speed, and a machining amount for each different machining performed on the workpiece using a tool. A machine tool according to any one of claims 6-9.
The setting unit sets the threshold to a value larger than a preset reference threshold when the machining direction is along the seating direction of the workpiece, and the machining direction is in the unseating direction of the workpiece. 11. The machine tool according to claim 10, wherein said threshold is set to a value smaller than said reference threshold for the along direction.
12. The determination unit determines, as the seating state, a state in which the workpiece is lifted from the seating surface of the seating portion based on the pressure applied to the workpiece during machining as the physical quantity. The machine tool described in .
The pressure changes depending on at least one of the magnitude of the machining load on the workpiece, the magnitude of the gripping force that grips the workpiece during machining, and the abnormality of a tool that performs machining on the workpiece. 13. The machine tool of claim 12.
14. The apparatus according to claim 13, wherein the determining unit further determines at least one of the magnitude of the machining load, the magnitude of the gripping force, and the abnormality of the tool based on the determination of the seating state. Machine Tools.