JP2026000180A - machine tools - Google Patents

Abstract

[Problem] To provide a machine tool capable of appropriately implementing support for vibration countermeasures. [Solution] The machine tool includes a tool holder that detachably holds a tool, and a control unit (4). The control unit (4) includes an estimation unit (163) and a simulation unit (170). The estimation unit (163) is configured to estimate the number of teeth of a tool attached to the tool holder. The simulation unit (170) is configured to use the number of teeth to perform a simulation of the behavior of the tool held in the tool holder. [Selected Figure] Figure 3

Description

The present invention relates to technology that assists in countering vibrations that occur in machine tools.

In machine tools, chatter vibrations can lead to reduced quality on the machined surface of a workpiece. The two main types of chatter vibration are regenerative chatter, which occurs when vibration-induced undulations on the machined surface cause fluctuations in the cutting depth of the tool, and forced chatter, which occurs due to resonance based on the natural frequency. Operators often deal with chatter vibrations based on their own experience. For example, operators listen to the sound of vibrations and observe the machined surface of the workpiece to predict the cause of the chatter vibrations and adjust the machining conditions. If the chatter vibrations persist, they may change the way the workpiece is fixed or change the tool. These countermeasures are selected based on the operator's own experience and knowledge. However, there are limits to measures based on the operator's own experience and knowledge. Japanese Patent Application Laid-Open No. 2023-4510 (Patent Document 1) discloses a machine tool that determines recommended machining conditions for suppressing chatter vibrations.

JP 2023-4510 A

In the technology described in Patent Document 1, tool information is stored in advance in the control unit of the machine tool. The machine tool then uses that tool information to determine recommended machining conditions and displays the recommended machining conditions to the user, thereby assisting with vibration countermeasures. However, if the necessary tool information is not stored in the control unit, vibration countermeasure support may not be implemented, or the accuracy of calculation of the recommended machining conditions may be reduced.

An object of one aspect of the present invention is to provide a machine tool that can appropriately implement vibration control support.

One aspect of the present invention is a machine tool that includes a tool holder that detachably holds a tool, an estimation unit that estimates the number of teeth of a tool attached to the tool holder, and a simulation unit that uses the number of teeth to perform a simulation of the behavior of the tool held in the tool holder.

One aspect of the present invention provides a machine tool that can appropriately implement vibration countermeasure support.

1 is a diagram schematically illustrating a general configuration of a machine tool according to an embodiment of the present invention. 1 is a perspective view showing a schematic configuration of a processing device according to an embodiment of the present invention; FIG. 2 is a functional block diagram of a control unit according to the present embodiment. FIG. 10 is a diagram illustrating an example of a home screen. 5 is a flowchart showing processing executed by a basic application in the machine tool according to the present embodiment. 10 is a flowchart showing a process for setting the number of blades according to the present embodiment. FIG. 10 is a diagram illustrating an example of a first setting screen. 6 is a flowchart showing details of a vibration monitoring process according to the present embodiment. FIG. 10 is a diagram showing an example of a first message screen. 4 is a flowchart showing a vibration monitoring process according to the present embodiment. FIG. 10 is a diagram illustrating an example of a vibration monitoring screen. FIG. 10 is a diagram illustrating an example of a tuning screen. FIG. 10 is a diagram showing a first example of a status screen. FIG. 10 is a diagram showing a second example of the status screen. FIG. 10 is a diagram illustrating an example of a second setting screen. 10 is a flowchart showing details of an adjustment process according to the present embodiment. 10 is a flowchart showing a process related to blade number setting management according to the present embodiment. FIG. 10 is a diagram illustrating an example of a second message screen. 18 is a flowchart showing a first modified example of the processing flow shown in FIG. 17. 18 is a flowchart showing a second modified example of the processing flow shown in FIG. 17. 18 is a flowchart showing a third modified example of the processing flow shown in FIG. 17. 18 is a flowchart showing a fourth modified example of the processing flow shown in FIG. 17. FIG. 2 is a diagram showing a modified example of the machine tool shown in FIG. 1 . 10 is a graph showing an example of the relationship between tool breakage and cutting force in a machine tool according to a modified example. 6 is a flowchart showing a modified example of the process of S12 in FIG. 5.

Embodiments of the present invention will be described with reference to the drawings. Note that in the drawings referred to below, identical or equivalent components are designated by the same numbers.

Figure 1 is a diagram showing a schematic configuration of a machine tool according to this embodiment. The machine tool 1 according to this embodiment is a horizontal machining center. The machine tool 1 includes a processing device 2, a control unit 4, a signal processing device 40, and a drive circuit 56. A control panel 54 is provided on the housing of the processing device 2. The control panel 54 has an input device 541, a display device 542, and a speaker 543. The control panel 54 according to this embodiment has a touch panel display that can be operated by an operator. This touch panel display functions as the input device 541 and the display device 542.

The machining device 2 is further provided with a camera 55 that photographs the tool T. The camera 55 is provided so that it can photograph the tool T being transported from a tool magazine (not shown) toward the spindle 18 for automatic tool change in the spindle 18. The camera 55 acquires image information indicating the state of the tool T and outputs it to the control unit 4.

The machining device 2 is further provided with a reader 19 capable of reading tool information from the tool T. The reader 19 is provided so as to be able to read tool information from the tool T that is transported from a tool magazine (not shown) toward the spindle 18 for automatic tool change in the spindle 18. Specifically, if the tool T is provided with an information display unit, the information displayed by the information display unit is read by the reader 19. The information display unit may be a label that displays at least one of a predetermined code (e.g., a barcode, a two-dimensional code, or a color code), a character string, and a numeric string, or may be an IC (integrated circuit) chip that stores information in a format readable by the reader 19. The tool information acquired by the reader 19 is output to the control unit 4.

The spindle 18 is also provided with a rotation sensor 18a that detects the rotational state (e.g., rotation speed) of the spindle 18, and a tool detection sensor 18b. The tool detection sensor 18b is configured to detect the attachment and detachment of a tool to the spindle 18. Information obtained by each of the rotation sensor 18a and the tool detection sensor 18b is output to the control unit 4.

Figure 2 is a perspective view showing the general configuration of the processing device 2 with the housing removed. In Figure 2, the left-right, up-down, and front-to-back directions when viewing the processing device 2 from the front are defined as the X-axis, Y-axis, and Z-axis directions, respectively.

The processing device 2 includes a bed 10, a column 12 erected on the bed 10, a spindle head 14, a table 16, a spindle 18, guide rails 22, 26, 32, and saddles 24, 34. The spindle head 14 has an axis in the Z-axis direction and supports the spindle 18 rotatably about that axis. The spindle head 14 is provided with a spindle motor for rotating the spindle 18. The spindle head 14 rotates the spindle 18 in accordance with instructions from the control unit 4. The spindle 18 removably holds a tool T. When the processing device 2 is in use, a holder portion 20 for the tool T is attached to the spindle 18 so that the tool T and the spindle 18 are coaxially arranged. This allows the tool T to be held by the spindle 18. The spindle 18 corresponds to an example of a "tool holding portion."

The spindle head 14 is movably mounted on the front side of the column 12. Specifically, a guide rail 22 is mounted on the front side of the column 12. The saddle 24 is supported on the guide rail 22 so as to be movable in the X-axis direction. A guide rail 26 is mounted on the front side of the saddle 24. The spindle head 14 is supported on the guide rail 26 so as to be movable in the Y-axis direction. The machining device 2 includes an XY drive device for moving (displacing) the saddle 24 and spindle head 14, such as a feed mechanism and a servo motor for driving the feed mechanism. The feed mechanism may be a screw feed mechanism using a ball screw. The XY drive device is controlled by the control unit 4. The spindle 18 is movable in the X- and Y-axis directions by driving the saddle 24 and spindle head 14. An acceleration sensor 30 is built into the spindle head 14.

A workpiece W is fixed to the table 16 via a jig (not shown). The table 16 is movably mounted on the bed 10. Specifically, guide rails 32 are provided on the upper surface of the bed 10. A saddle 34 is supported on the guide rails 32 so that it can move in the Z-axis direction. The table 16 is fixed on the saddle 34. The processing device 2 includes a Z-drive device for moving (displacing) the saddle 34, such as a feed mechanism and a servo motor for driving the feed mechanism. The feed mechanism may be a screw feed mechanism using a ball screw. The Z-drive device is controlled by the control unit 4. The workpiece W is movable in the Z-axis direction by driving the saddle 34. The processing device 2 can adjust the relative position of the workpiece W and the tool T in three dimensions.

The control unit 4 shown in FIG. 1 detects chatter vibrations of the tool T held by the spindle 18 based on the output signal of the acceleration sensor 30 built into the spindle head 14. Specifically, the acceleration sensor 30 detects vibrations occurring in the tool T during machining of the workpiece W and outputs a signal corresponding to the vibrations. The acceleration data detected by the acceleration sensor 30 is input to a signal processing device 40. The signal processing device 40 includes an A/D converter 42 and a frequency analyzer 44. The analog signal output from the acceleration sensor 30 is converted to a digital signal by the A/D converter 42 and then input to the frequency analyzer 44. The frequency analyzer 44 performs FFT (fast Fourier transform) processing on the input digital signal. The vibration data subjected to FFT processing by the frequency analyzer 44 is input to the control unit 4.

The control unit 4 includes a control device 50 and a vibration processing device 52. The vibration processing device 52 acquires the vibration data from the signal processing device 40 (frequency analysis device 44). The vibration processing device 52 receives information indicating the control state from the control device 50 and sends control commands to the control device 50. Based on the signals received from the signal processing device 40 and the control device 50, the vibration processing device 52 performs predetermined processing regarding the vibration of the tool T held by the spindle 18. For example, based on the signal input from the signal processing device 40, the vibration processing device 52 displays a screen (status screen) showing the vibration state of the spindle 18 and determines whether chatter vibration is present.

The control device 50 controls actuators (e.g., motors) according to a machining program that is manually or automatically generated. The machining program is, for example, an NC (Numerical Control) program. For example, when performing a turning operation on the workpiece W, the control device 50 may drive a servo motor via the drive circuit 56 to feed and drive the spindle head 14. The control device 50 may also rotate the spindle 18 by driving a spindle motor via the drive circuit 56.

Figure 3 is a functional block diagram of the control unit 4. The control unit 4 includes a processor, such as a CPU (Central Processing Unit), and a storage device, including, for example, memory and storage. The storage device stores a computer program. In this embodiment, each component of the control unit 4 shown in Figure 3 is realized by, for example, hardware, such as a processor, and a computer program (software) that supplies processing instructions to the processor. The computer program may include a device driver, an operating system, various application programs located at higher levels, and libraries that provide common functions to these programs. Each part shown in Figure 3 corresponds to a functional unit (functional block) rather than a hardware unit.

The control unit 4 includes an HMI (Human Machine Interface) processing unit 110, a data processing unit 112, a data storage unit 114, and a detection unit 116. The HMI processing unit 110 is responsible for processing related to the user interface. The data processing unit 112 performs various processes based on information acquired by the HMI processing unit 110, information stored in the data storage unit 114, and information detected by the detection unit 116. The data processing unit 112 also functions as an interface for each of the HMI processing unit 110, data storage unit 114, and detection unit 116.

The HMI processing unit 110 includes an input unit 120. When a user operation is input to the input device 541 (Figure 1), a signal corresponding to the user operation is output to the input unit 120. The input unit 120 acquires information based on the signal input from the input device 541. The input unit 120 includes a tool information receiving unit 122 and a condition receiving unit 124. The tool information receiving unit 122 receives tool information related to the tool T (e.g., tool type, tool diameter, and number of teeth). The condition receiving unit 124 receives information related to machining conditions such as the spindle rotation speed or feed rate. In this embodiment, a touch panel display functions as the input device 541. However, the configuration of the input device 541 can be changed as appropriate. The input device 541 may also be configured as a physical operation unit (e.g., button, handle, dial, etc.).

Information about the tool T (e.g., tool T's identification information, model number, or other tool information) read by the reader 19 (Figure 1) is also input to the input unit 120. The information acquired by the input unit 120 is converted into a format that can be processed by the data processing unit 112, and then output to the data processing unit 112.

The HMI processing unit 110 further includes an output unit 128. The output unit 128 provides various types of information to the operator. The output unit 128 provides visible information (e.g., images) to the operator via a display device 542 (Figure 1). The output unit 128 also provides sound information (including voice) to the operator via a speaker 543 (Figure 1). The output unit 128 may cause the display device 542 to display at least one of an information screen showing information about the machine tool 1 and an operation screen (e.g., a keyboard and machine operation panel) that accepts user operations. In this embodiment, a touch panel display functions as the display device 542. However, the display device 542 may also include lamps and/or warning lights.

The detection unit 116 includes a vibration detection unit 130 and a rotational speed detection unit 132. The vibration detection unit 130 detects vibrations of the spindle 18 (and therefore vibrations of the tool T) based on the sensor output from the acceleration sensor 30 (Figure 1). Specifically, the vibration detection unit 130 acquires vibration data output from the signal processing device 40. The rotational speed detection unit 132 detects the rotational speed of the spindle 18 (and therefore the rotational speed of the tool T) based on the output of a rotation sensor 18a (Figure 1) provided on the spindle 18. An example of the rotation sensor 18a is a rotary encoder.

The data storage unit 114 includes a program storage unit 140, a tool data storage unit 142, a display data storage unit 144, and a history data storage unit 146. The program storage unit 140 stores machining programs (e.g., NC programs). The tool data storage unit 142 stores information (tool information) about multiple types of tools that can be used with the machine tool 1, in association with tool identification information (tool ID). The tool information includes, for example, the tool type, tool diameter, and number of teeth. The tool data storage unit 142 may manage tool information by tool type. Tool information may also be distinguished by tool model number. The range of machining conditions that can be adjusted by the vibration processing device 52 (Figure 1) (hereinafter also referred to as the "adjustment range") may also be included in the tool information. The display data storage unit 144 stores screen data to be displayed on the display device 542 (e.g., softkeys and dialog boxes to be displayed on the screen).

The history data storage unit 146 stores time-series data of status information indicating the state of the machining device 2 (e.g., the control state and vibration state of the spindle 18). The status information includes, for example, at least one of the vibration level, spindle rotation speed, adjustment instruction timing, program line (program block number) where chatter vibration occurred, and peak frequency. Each time new data (status information) is acquired, the acquired data is associated with the acquisition time and stored in the history data storage unit 146. If the amount of accumulated data exceeds the storage capacity of the history data storage unit 146, the oldest data may be deleted.

The data processing unit 112 includes a numerical control unit 150, a notification control unit 156, a display control unit 158, a tool information management unit 160, and a simulation unit 170. The numerical control unit 150 is embodied, for example, as a function of the control device 50 (Figure 1). The simulation unit 170 is embodied, for example, as a function of the vibration processing device 52 (Figure 1). The configuration shown in Figure 1 may be modified so that at least a portion of the signal processing device 40 is included in the control unit 4. For example, the simulation unit 170 may have the function of the frequency analysis device 44.

The numerical control unit 150 controls the machining device 2 in accordance with the machining program stored in the program storage unit 140, for example, based on commands input from the input unit 120. The numerical control unit 150 may also control the machining device 2 in response to a request from the simulation unit 170. The numerical control unit 150 sequentially transmits information indicating the current control state (control information) to the simulation unit 170. The control information includes, for example, a control value for the spindle rotation speed.

The tool information management unit 160 sets information related to the tool T held by the spindle 18. The tool information management unit 160 also stores the set information separately from other information. The tool information management unit 160 is configured to be able to acquire tool information from the HMI processing unit 110 (input unit 120). In this embodiment, the tool information management unit 160 includes a first setting unit 161, a second setting unit 162, and an estimation unit 163.

The first setting unit 161 uses information input by the user to set the parameters (tool information) of the tool T held by the spindle 18. The first setting unit 161 sets, for example, the number of teeth input by the operator to the input device 541 as the number of teeth of the tool T.

The second setting unit 162 sets the parameters (tool information) of the tool T held in the spindle 18 using information read by the reader 19 (Figure 1). For example, during automatic tool replacement in the spindle 18, the second setting unit 162 sets the number of teeth of the tool T attached to the spindle 18 using information (e.g., tool ID) presented by an information presentation unit provided on the replaced tool T. The second setting unit 162 may obtain the number of teeth of the tool T from the tool information stored in the tool data storage unit 142 based on the tool ID of the tool T, and set the obtained number of teeth of the tool T.

The estimation unit 163 is configured to estimate the number of teeth of the tool T attached to the spindle 18. The estimation unit 163 estimates the number of teeth of the tool T, for example, using at least one of information acquired by the acceleration sensor 30 and information acquired by the camera 55. As will be described in detail below, the estimation unit 163 estimates the number of teeth when predetermined estimation conditions are met, and sets the estimated number of teeth as the number of teeth of the tool T.

The simulation unit 170 performs a simulation of the behavior (e.g., vibration) of the tool T using the number of teeth of the tool T held by the spindle 18. Specifically, the simulation unit 170 includes a chatter detection unit 171, a recommended condition calculation unit 172, and a tuning management unit 173.

In the simulation, the frequency analyzer 44 shown in FIG. 1 receives the signal continuously output from the acceleration sensor 30 and performs Fourier analysis (frequency analysis) on the signal at a predetermined sampling interval. The simulation unit 170 acquires the vibration data that has been subjected to FFT processing from the frequency analyzer 44 and, based on the vibration data, acquires the frequency (vibration frequency) and magnitude (vibration level) of the vibration occurring in the tool T. The chatter detection unit 171 determines that chatter vibration has occurred when the vibration level exceeds a predetermined threshold. The recommended condition calculation unit 172 calculates recommended machining conditions for the tool T by performing a simulation using the number of teeth of the tool T held in the spindle 18. More specifically, when chatter vibration occurs, the recommended condition calculation unit 172 calculates machining conditions (recommended machining conditions) that will suppress the chatter vibration. An example of a recommended machining condition is a recommended value for the spindle rotation speed (hereinafter also referred to as the "recommended rotation speed").

When regenerative chatter is detected as chatter vibration, the recommended condition calculation unit 172 may calculate a recommended rotational speed SS (recommended value) from the vibration frequency ω0 (chatter frequency) at that time and the number of teeth n of tool T according to the following equation (1). "k" in equation (1) is an integer greater than or equal to 1. "n" in equation (1) corresponds to the number of teeth of the tool (tool T) currently in use.

SS=(60×ω0)/(n×k)...(1)
The recommended condition calculation unit 172 calculates the recommended rotational speed SS according to Equation (1) using the number of teeth n of the set tool T. The recommended condition calculation unit 172 acquires the number of teeth n from the tool information management unit 160. The recommended rotational speed SS is a rotational speed corresponding to the kth-order stable pocket in the stability limit diagram. Such a recommended rotational speed SS corresponds to a spindle rotational speed at which chatter vibration is unlikely to occur. For example, if the spindle rotational speed when chatter vibration occurs is "S0" and the kth-order (e.g., second-order) recommended rotational speed SS obtained by Equation (1) is within the stable region, the control unit 4 can converge the chatter vibration by changing the spindle rotational speed from S0 to the recommended rotational speed SS. Note that the recommended machining conditions calculated by the recommended condition calculation unit 172 are not limited to the recommended rotational speed, and may also be a recommended feed rate.

The tuning management unit 173 sets the recommended machining conditions for tool T, a vibration detection flag indicating whether chatter vibration is detected, an adjustment flag indicating whether the user is permitted to change (adjust) the machining conditions, and a notification flag indicating whether the notification control unit 156 (described below) is enabled. In the initial state, the vibration detection flag is set to "no detection (0)," the adjustment flag is set to "prohibited (0)," and the notification flag is set to "enabled (1)." However, the initial values of each flag can be set arbitrarily. The tuning management unit 173 stores the set information (hereinafter also referred to as "tuning information") separately from other information. The tuning information update process will be described later.

The notification control unit 156 executes notification control to prompt a user operation (for example, an information input operation, a screen switching operation, or an application launch operation). In this embodiment, the notification control unit 156 prompts the operator to input the number of teeth of the tool T. The notification control unit 156 is configured to be able to control the display device 542 and the speaker 543 via the output unit 128. The notification control unit 156 may also control the display device 542 and/or the speaker 543 so that the operation panel 54 issues a notification prompting a user operation. As will be described in more detail below, the notification control unit 156 executes notification control to guide the operator to input the number of teeth of the tool T when a predetermined notification condition is met.

The display control unit 158 is configured to execute display control to display information related to the processing device 2. The display control unit 158 is configured to be able to control the display device 542 via the output unit 128. The display control unit 158 may cause the display device 542 to display the recommended processing conditions calculated by the recommended condition calculation unit 172. As will be described in detail below, the display control unit 158 may cause the display device 542 to display at least one of the following in response to user operation: a status screen showing the control status of the processing device 2; a tuning screen for monitoring vibrations; a program screen showing the control program for the processing device 2; a first setting screen for setting tool information; and a second setting screen for switching the enable/disable setting of the notification control unit 156.

For example, when a basic application for using the machine tool 1 is launched in response to a user operation, the display control unit 158 causes a home screen to be displayed on the operation panel 54 (touch panel display). Figure 4 is a diagram showing an example of a home screen. The home screen Sc1 shown in Figure 4 is an operation screen with touch panel functionality, and displays multiple buttons (including buttons P1 and P2) that the operator can select. For example, multiple buttons for launching various programs are displayed. Button P1 is a launch button for an application for managing tools T (hereinafter also referred to as the "tool management app"). Button P2 is a launch button for an application for suppressing chatter vibrations (hereinafter also referred to as the "vibration control app").

When the basic application is launched, the control unit 4 executes the processing flow F1 described below. Figure 5 is a flowchart showing the processing executed in the basic application. "S" in the flowchart indicates a step.

In process flow F1 shown in FIG. 5, the control unit 4 determines in S11 whether the number of teeth of the tool T held by the spindle 18 has been set. The control unit 4 determines whether the number of teeth of the tool T has been set, for example, based on whether the tool information management unit 160 manages the number of teeth of the tool T. If the number of teeth of the tool T has been set (YES in S11), the process proceeds to S12. The process of S12 will be described later. On the other hand, while the number of teeth of the tool T has not been set (NO in S11), the determination in S11 is repeated. Then, once the number of teeth of the tool T has been set, the process of S12 is executed. In S12, the vibration monitoring process (see FIG. 8), described later, is executed.

The operator can set the number of teeth of the tool T through the tool management app. The operator can launch the tool management app by operating button P1 on the home screen Sc1 shown in Figure 4. When a predetermined user operation (hereinafter also referred to as the "first setting operation") is performed in the tool management app, the control unit 4 executes processing flow F2, which will be described below. Figure 6 is a flowchart showing the processing related to setting the number of teeth.

In process flow F2 shown in Figure 6, the control unit 4 (display control unit 158) displays a first setting screen on the operation panel 54 (touch panel display) in S21. Figure 7 is a diagram showing an example of the first setting screen. The first setting operation is, for example, an operation of selecting the "Chatter Control" tab (see Figure 7) in the tool management app.

The first setting screen Sc2 shown in FIG. 7 accepts input of information (tool information) related to tool T. Specifically, the first setting screen Sc2 includes an input section P21 that accepts input of the number of blades, an input section P22 that accepts input of the minimum spindle override, an input section P23 that accepts input of the maximum spindle override, and an input section P24 that accepts input of the tool diameter. However, the content displayed on the first setting screen can be changed as appropriate.

In S22 of FIG. 6, the control unit 4 (tool information receiving unit 122) determines whether the operator has input tool information on the first setting screen. If no tool information has been input on the first setting screen (NO in S22), the process skips S23 and proceeds to S24. On the other hand, if tool information has been input (YES in S22), the control unit 4 (tool information management unit 160) sets the input tool information in S23. Unset tool information is changed to "set" by the setting in S23. On the other hand, for set tool information, the value is updated by the new setting. The set tool information is managed by the tool information management unit 160. For example, if the number of teeth is input, the number of teeth is set. As a result, a "YES" determination is made in S11 of FIG. 5. If at least one of the minimum spindle override and the maximum spindle override is input, the adjustment range of the tool T is updated. If a tool diameter is input, the tool diameter is set. The set tool diameter may be used to calculate the peripheral speed.

When the settings in S23 are complete, processing proceeds to S24. In S24, the control unit 4 determines whether or not to end the display of the first setting screen. If neither the system nor the operator has requested that the display of the first setting screen be ended, a NO determination is made in S24, and processing returns to the first step (S21). This allows the display of the first setting screen to continue. On the other hand, for example, if the operator performs an operation to end the display, a YES determination is made in S24, and processing flow F2 ends. An operation to end the display of the first setting screen is, for example, an operation to select a tab other than the "Chatter Control" tab in the tool management app (such as the "General" tab shown in FIG. 7).

If the number of teeth of the tool T held by the spindle 18 has already been set, the vibration monitoring process is executed in S12 of Figure 5. Figure 8 is a flowchart showing the vibration monitoring process in detail.

In process flow F3 shown in Figure 8, the control unit 4 (detection unit 116) acquires vibration data and rotation speed of the spindle 18 in S31. Subsequently, in S32, the control unit 4 determines whether the processing device 2 is currently cutting based on the information acquired in S31. If the processing device 2 is not currently cutting (NO in S32), the process proceeds to S361. On the other hand, if the processing device 2 is currently cutting (YES in S32), the process proceeds to S33.

In S33, the control unit 4 acquires current status information and adds the acquired status information to the history data storage unit 146 in association with the current time. In the following S34, the control unit 4 determines whether chatter vibration is occurring in the tool T held by the spindle 18. Specifically, the simulation unit 170 acquires the frequency (vibration frequency) and magnitude (vibration level) of vibration occurring in the tool T based on the vibration data acquired in S31, and determines whether chatter vibration has been detected by the chatter detection unit 171. If chatter vibration is not detected (NO in S34), the process proceeds to S361. On the other hand, if chatter vibration is detected (YES in S34), the process proceeds to S35.

In S361, the control unit 4 updates the tuning information. Specifically, the tuning management unit 173 sets the vibration detection flag to "no detection (0)" and the adjustment flag to "prohibited (0)." Processing then proceeds to S39.

In S35, the control unit 4 calculates recommended cutting conditions for suppressing chatter vibrations occurring in the tool T held by the spindle 18. Specifically, the recommended condition calculation unit 172 calculates the recommended cutting conditions for the tool T by performing a simulation using the number of teeth of the tool T held by the spindle 18. The recommended condition calculation unit 172 may calculate the recommended rotation speed based on the above-mentioned equation (1). The recommended condition calculation unit 172 may calculate multiple recommended values. The recommended condition calculation unit 172 may calculate a first recommended value that is higher than the current control value of the spindle rotation speed and a second recommended value that is lower than the current control value of the spindle rotation speed.

The control unit 4 then updates the tuning information in S362. Specifically, the tuning management unit 173 sets the recommended machining conditions for tool T calculated by the recommended condition calculation unit 172. The tuning management unit 173 also sets the vibration detection flag to "Detected (1)."

In the following step S371, the control unit 4 determines whether the vibration monitoring screen (see Figures 11 to 13), which will be described later, is being displayed. If the vibration monitoring screen is being displayed (YES in S371), processing proceeds to S39. On the other hand, if the vibration monitoring screen is not being displayed (NO in S371), processing proceeds to S372.

In S372, the control unit 4 determines whether the notification control unit 156 is enabled. Specifically, if the notification flag is set to "disabled (0)," a NO determination is made in S372 and processing proceeds to S39. On the other hand, if the notification flag is set to "enabled (1)," a YES determination is made in S372 and processing proceeds to S38.

In S38, the control unit 4 executes notification control to prompt the user to display the vibration monitoring screen. Specifically, the notification control unit 156 causes the operation panel 54 (display device 542) to display a first message screen including, for example, a message prompting the user to display the vibration monitoring screen. The first message screen may be displayed as a pop-up. Figure 9 is a diagram showing an example of the first message screen. The message screen Sc3 shown in Figure 9 includes a message indicating that vibration has been detected by the simulation unit 170 (i.e., that chatter vibration has been detected), a message prompting the user to display the vibration monitoring screen ("Chatter Control" screen), and a message instructing the user how to disable the notification (processing of S38). However, the content displayed on the first message screen can be changed as appropriate.

When the processing of S38 is executed, the processing proceeds to S39 while the first message screen remains displayed. The control unit 4 terminates the display of the first message screen in response to a user operation. The operator can terminate the display of the first message screen at any time.

In S39, the control unit 4 determines whether or not to shut down the system of the machine tool 1. For example, when the operation of the machine tool 1 is stopped in accordance with instructions from the system or the operator, it is determined that the system should be shut down (YES in S39), and process flow F3 ends. In this case, the control unit 4 executes system shutdown processing and shuts down the system. On the other hand, if it is determined that the system should not be shut down (NO in S39), the process returns to the first step (S31). Process flow F3 is repeatedly executed while the system is operating.

The control unit 4 executes display control to display a vibration monitoring screen in response to a predetermined user operation (hereinafter also referred to as a "vibration monitoring operation"). Specifically, the operator can launch the vibration control app by operating button P2 on the home screen Sc1 shown in FIG. 4. When the vibration control app is launched, the control unit 4 executes processing flow F4, which will be described below. In this embodiment, the user operation on button P2 corresponds to the vibration monitoring operation. While processing flow F4 is being executed, processing flow F1 shown in FIG. 5 is also executed repeatedly in the background.

Figure 10 is a flowchart showing processing related to vibration monitoring. In processing flow F4, the control unit 4 (display control unit 158) displays a vibration monitoring screen on the operation panel 54 (touch panel display) in S41. Figure 11 is a diagram showing an example of the vibration monitoring screen.

The vibration monitoring screen Sc4 includes an operation unit M1 and tabs M2 and M3. The operation unit M1 accepts a user operation to terminate the vibration control app. The tabs M2 and M3 accept a user operation to switch screens. Either tab M2 or M3 is selected by the operator. On the vibration monitoring screen Sc4 shown in FIG. 11, tab M2 has been selected. The vibration monitoring screen Sc4 further includes a status screen Sc41, a tuning screen Sc42, and a program screen Sc43. The display control unit 158 controls the display of the program screen Sc43 based on the program information stored in the program storage unit 140. The program screen Sc43 displays the machining program currently being executed.

Figure 12 is a diagram showing an example of a tuning screen. The tuning screen Sc42 shown in Figure 12 includes an override bar M20, data D21-D24, a judgment result D25, markers M21-M23, and operation units M24-M27. The display control unit 158 controls the display of the tuning screen Sc42 based on, for example, status information (including vibration levels) stored in the history data storage unit 146 and tuning information (including recommended processing conditions and vibration detection flags) managed by the tuning management unit 173. The status information and tuning information are updated sequentially by process flow F3 shown in Figure 8.

The override bar M20 is a scale object that extends to the left and right of the screen and provides an override scale. The override represents the percentage change in the spindle speed control value relative to the current program command value for the spindle speed. The program command value is the spindle speed specified by the machining program. The program command value does not change unless a new value is specified in the program. The spindle speed control value is the spindle speed control command value received by the machining device 2, and may be, for example, a spindle speed specified by a PLC (Programmable Logic Controller). If control is performed correctly, the actual spindle speed detected by the rotation sensor 18a will roughly match the spindle speed control value.

In the override bar M20, the center position indicates 100% of the program command value, and the positions on both ends indicate the adjustment range for the spindle rotation speed. In the example shown in Figure 12, the right-hand position indicates 150% of the program command value (change rate of "+50%)," and the left-hand position indicates 50% of the program command value (change rate of "-50%)." In other words, the adjustment range for the spindle rotation speed is set to a range of 50 to 150% of the program command value. This prevents sudden changes in the rotation speed (control state) of the spindle 18 beyond the operator's expectations.

The data D21 and marker M21 indicate the current control command value of the spindle rotation speed (for example, 2500 min ⁻¹ ) relative to the override bar M20. When the machining conditions (particularly the spindle rotation speed) have not been adjusted, the marker M21 is displayed at the 100% position, as shown in FIG. 12. That is, the control value of the spindle rotation speed is equal to the program command value. On the other hand, when the machining conditions (particularly the spindle rotation speed) are changed by the adjustment process (FIG. 16) described later, the display position of the marker M21 is changed according to the rate of change.

Of the one or more recommended values (recommended machining conditions) calculated in S35 of FIG. 8, only those within the adjustment range are displayed on the tuning screen. Recommended values outside the adjustment range are not displayed on the tuning screen. Furthermore, when chatter vibration is not occurring, the process of S35 of FIG. 8 is not executed, and therefore recommended machining conditions are not displayed on the tuning screen. In the tuning screen Sc42 shown in FIG. 12, data D22 and a marker M22 indicate a first recommended value for the spindle rotation speed (e.g., 2878 min ⁻¹ ) for the override bar M20. Data D23 and a marker M23 indicate a second recommended value for the spindle rotation speed (e.g., 2466 min ⁻¹ ) for the override bar M20. The operator can select one recommended value from the first recommended value and the second recommended value displayed on the tuning screen Sc42 by operating the operation unit M24 or M25.

Data D24 indicates the vibration state of the main shaft 18. In the example shown in Figure 12, data D24 indicates the currently detected vibration level (68 dB) and peak frequency (1152 Hz). The peak frequency refers to the vibration frequency at which the vibration level is at its maximum.

The determination result D25 indicates whether or not vibration has been detected. In the example shown in FIG. 12, the determination result D25 indicates that chatter vibration is occurring (for example, the text "Chatter occurring"). This means that the vibration detection flag is set to "Detected (1)." If the vibration detection flag is set to "Not detected (0)," the display content of the determination result D25 changes. If the chatter vibration has been resolved by the adjustment process, a message indicating this (for example, the text "Chatter vibration avoided") may be displayed as the determination result D25.

Operation unit M26 (e.g., a "reset button") accepts a user operation to instruct an override reset process (hereinafter also referred to as a "reset operation"). When operation unit M26 receives a reset operation, the control unit 4 returns the override to 100% (no change). However, if a reset prohibition condition is met, operation unit M26 becomes inactive. The reset prohibition condition can be set arbitrarily. Operation unit M27 (e.g., an "adjustment button") accepts a user operation to instruct the start of adjustment processing to suppress chatter vibration (hereinafter also referred to as an "adjustment start operation"). Operation unit M27 becomes active when the adjustment flag is set to "permit (1)" and becomes inactive when the adjustment flag is set to "prohibit (0)." User operations on an inactive operation unit are invalid. An inactive operation unit may be displayed grayed out.

Figure 13 is a diagram showing a first example of a status screen. The status screen Sc41 shown in Figure 13 includes a marker M10, operation units M11 to M13, and data D11 and D12. The display control unit 158 controls the display of the status screen Sc41 based on, for example, status information (including vibration level and spindle rotation speed) stored in the history data storage unit 146. The status information is updated sequentially by processing flow F3 shown in Figure 8.

Data D11 indicates the transition of the vibration level (dB). Data D12 indicates the transition of the spindle rotation speed (min ⁻¹ ). The operator can switch data collection between enabled (ON) and disabled (OFF) via the operation unit M11. When data collection is enabled, the display contents of the status screen Sc41 are updated with the latest data each time status information (including the vibration level and the spindle rotation speed) is calculated in S33 of FIG. 8 . For example, data D11 and D12 display changes in the vibration level and the spindle rotation speed in real time. On the other hand, when data collection is disabled, the display contents of the status screen Sc41 are not updated. In addition, the operator can change the scale of the horizontal axis of the graph on which data D11 and D12 are displayed by operating the operation units M12 and M13.

The marker M10 indicates the timing of an adjustment instruction for the status information (data D11, D12) displayed on the status screen. The adjustment instruction timing is the timing at which the operator instructs the adjustment process. In this embodiment, the timing at which the active operation unit M27 (Figure 12) receives an adjustment start operation corresponds to the adjustment instruction timing.

When data collection is disabled, for example, past data is displayed on the status screen. Figure 14 shows a second example of the status screen. When data collection is disabled, the display control unit 158 may display a history data screen Sc44 on the operation panel 54 (touch panel display) in addition to the status screen Sc41. In the status screen Sc41 shown in Figure 14, data D11 and D12 indicate past vibration levels and spindle rotation speeds. The history data screen Sc44 shows adjustment history information related to data D11 and D12. The adjustment history information includes, for example, the total number of adjustments, changes to the spindle rotation speed, changes to the feed rate, the program name, and the program line (block number). If the total number of adjustments is multiple, the adjustment history information is displayed for each adjustment number indicating the number of adjustments. The operator can select an adjustment number using the operation unit M40 to display the adjustment history information corresponding to the selected adjustment number on the history data screen Sc44. The display control unit 158 may read status information (history data) for a period specified by the operator from the history data storage unit 146 and display it on the display device 542.

In S42 of FIG. 10, the control unit 4 (condition receiving unit 124) determines whether the operator has selected one recommended value from the recommended processing conditions displayed on the tuning screen. If one recommended value is not selected on the tuning screen (NO in S42), processing proceeds to S46. On the other hand, if, for example, either the first recommended value or the second recommended value is selected using operation unit M24 or M25 on tuning screen Sc42 (FIG. 12), a YES determination is made in S42, and processing proceeds to S43.

In S43, the control unit 4 updates the tuning information. Specifically, the tuning management unit 173 sets the adjustment flag to "Allowed (1)." This allows the operator to adjust (tune) the processing conditions by operating the operation unit M27 (adjustment button) on the tuning screen Sc42 (FIG. 12). Next, in S44, the control unit 4 determines whether an adjustment start operation (e.g., pressing the adjustment button) by the operator has been detected. If an adjustment start operation has not been detected (NO in S44), the process proceeds to S46.

In S46, the control unit 4 determines whether to terminate the vibration control app. If neither the system nor the operator has requested termination of the vibration control app, a NO determination is made in S46, and processing proceeds to S47. In S47, the control unit 4 determines whether a predetermined user operation (hereinafter also referred to as a "second setting operation") has been performed in the vibration control app. The second setting operation is, for example, selecting tab M3 on the vibration monitoring screen Sc4 (FIG. 11). If the second setting operation is not received from the operator (NO in S47), processing returns to the first step (S41). On the other hand, if the second setting operation is performed in the vibration control app (YES in S47), the control unit 4 (display control unit 158) displays a second setting screen on the operation panel 54 (touch panel display) instead of the tuning screen in S51. FIG. 15 is a diagram showing an example of the second setting screen.

The second setting screen Sc5 shown in FIG. 15 accepts user operations for setting parameters related to the vibration control app. Specifically, the second setting screen Sc5 includes an operation unit P3 that accepts user operations for switching notifications on and off. The operator can change the notification settings via the operation unit P3. In S52 of FIG. 10, the control unit 4 determines whether the notification settings have been changed by the operator.

If the notification setting has been changed (YES in S52), the control unit 4 (tuning management unit 173) updates the notification flag in S53 in response to the user's operation on the operation unit P3. Specifically, if the notification setting has been changed from off to on, the notification flag is set to "enabled (1)" and notification will be performed by the notification control unit 156 (for example, processing in S38 in FIG. 8). On the other hand, if the notification setting has been changed from on to off, the notification flag is set to "disabled (0)" and notification will no longer be performed by the notification control unit 156.

When the processing of S53 is executed, the processing proceeds to S54. On the other hand, if the notification settings have not been changed (NO in S52), the processing skips S53 and proceeds to S54. In S54, the control unit 4 determines whether the user settings in the vibration control app have been completed. If the user settings have not been completed (NO in S54), the processing returns to S51. As a result, the second setting screen continues to be displayed. On the other hand, for example, if the operator performs an operation to end the settings, a YES determination is made in S54, and the processing returns to S41. As a result, the display of the second setting screen ends, and the tuning screen is displayed again instead. The setting end operation is, for example, an operation to select tab M2 on the vibration monitoring screen Sc4 (Figure 11).

The vibration control app displays a vibration monitoring screen (S41). Then, when the active operation unit M27 receives an adjustment start operation on the tuning screen Sc42 (FIG. 12), a YES determination is made in S44 and processing proceeds to S45. In S45, the control unit 4 executes tuning processing (adjustment processing). FIG. 16 is a flowchart showing the details of the tuning processing (adjustment processing).

In process flow F6 shown in Figure 16, the control unit 4 changes the machining conditions of the machine tool 1 in S61 to bring them closer to the tuning information (recommended machining conditions). Specifically, the simulation unit 170 outputs the recommended value selected by the operator (see S42 in Figure 10) to the numerical control unit 150. The numerical control unit 150 then changes the control value of the spindle rotation speed to the recommended value (recommended rotation speed) and controls the spindle 18.

Next, in S62, the control unit 4 (display control unit 158) updates the status screen and tuning screen based on the latest status information and tuning information. The status information and tuning information are updated sequentially in S12 (processing flow F3) of processing flow F1 (Figure 5), which is repeatedly executed in the background while processing flow F6 is being executed.

Next, in S63, the control unit 4 determines whether the adjustment termination condition is met. In this embodiment, the adjustment termination condition is met when the chatter vibration has converged (i.e., when a NO judgment is made in S34 of FIG. 8). However, the adjustment termination condition may also be met when the chatter vibration has become larger than before the start of the adjustment process, or when the type or frequency of the chatter vibration has changed. The adjustment termination condition can be set arbitrarily.

If the adjustment termination condition is not met (NO in S63), the control unit 4 determines in S64 whether the recommended value (e.g., recommended rotation speed) recalculated in S35 of FIG. 8 after the machining conditions were changed is within the adjustment range. If the recalculated recommended value is within the adjustment range (YES in S64), processing proceeds to S65. This allows the machining condition adjustment processing to continue. In S65, the control unit 4 changes the machining conditions (e.g., spindle rotation speed) of the machine tool 1 so that they approach the recalculated recommended value. Processing then returns to S62.

As long as the recalculated recommended value after changing the machining conditions is within the adjustment range (YES in S64) and the adjustment termination condition is not met (NO in S63), the machining condition adjustment process continues. On the other hand, if the adjustment termination condition is met (YES in S63) or if the recalculated recommended value is outside the adjustment range (NO in S64), processing proceeds to S66, which ends the adjustment process. In S66, the control unit 4 (tuning management unit 173) sets the adjustment flag to "prohibited (0)." This causes the operation unit M27 (adjustment button) on the tuning screen Sc42 (Figure 12) to become inactive. When the processing of S66 is executed, processing flow F6 ends, and processing proceeds to S46 in Figure 10.

If it is determined in S46 of FIG. 10 that the vibration control app should be terminated, processing flow F4 ends. For example, if the operator operates the operation unit M1 on the vibration monitoring screen Sc4 shown in FIG. 11, a YES determination is made in S46. In this case, the control unit 4 terminates the display of the vibration monitoring screen Sc4 and terminates the vibration control app.

In the machine tool 1 according to this embodiment, when the tool T held by the spindle 18 is replaced, if the number of teeth of the replaced tool T has not been set, the vibration monitoring process shown in FIG. 8 (S12 in FIG. 5) is not executed. In a situation where the vibration monitoring process is not being executed, calculation of recommended machining conditions for suppressing chatter vibration is not performed. As a result, the occurrence of chatter vibration during machining (cutting) is likely to degrade the quality of the machined surface of the workpiece.

The control unit 4 (controller) in this embodiment therefore executes process flow F7, described below, to prevent the number of teeth from remaining unset after a tool change. Process flow F7 makes it easier for the operator to set the number of teeth, or for the system to automatically set the number of teeth based on its estimation, at an early stage when changing tools.

Figure 17 is a flowchart showing the process related to tool blade count setting management. Process flow F7 shown in Figure 17 is initiated, for example, during tool replacement. In this embodiment, the control unit 4 executes a tool replacement process to replace a first tool (tool T before replacement) held by the spindle 18 with a second tool (tool T after replacement) in accordance with a tool replacement program stored in the program storage unit 140 (Figure 3). Specifically, upon initiation of the tool replacement process, a tool transport device (not shown) transports the second tool from the tool magazine to a predetermined standby position. During this time, the reader 19 may read tool information from the second tool, or the camera 55 may photograph the second tool. Next, an automatic tool changer (not shown) replaces the first tool held by the spindle 18 with the second tool positioned at the standby position. This completes the tool replacement process. The control unit 4 initiates process flow F7, described below, simultaneously with the initiation of the tool replacement process, or during or immediately after the completion of the tool replacement process.

In S71, the control unit 4 determines whether the number of teeth of the second tool has been set. For example, if the number of teeth of the second tool has been set based on the second tool information acquired by the reader 19 (i.e., information presented by the second tool information presentation unit), a YES determination is made in S71. For example, if the information acquired by the reader 19 from the second tool information presentation unit indicates the number of teeth of the second tool, the second setting unit 162 sets the number of teeth of the second tool. Also, if the information acquired by the reader 19 from the second tool information presentation unit includes identification information of the second tool and the tool information management unit 160 acquires the number of teeth of the second tool from the tool data storage unit 142 (Figure 3) based on the identification information of the second tool, the second setting unit 162 sets the number of teeth of the second tool. However, this does not necessarily mean that the tool data storage unit 142 stores the number of teeth of the second tool. If a YES determination is made in S71, processing flow F7 ends without executing S72 and subsequent steps.

On the other hand, if the number of teeth of the second tool has not been set (NO in S71), processing proceeds to S72. In S72, the control unit 4 determines whether the second tool is a tool corresponding to the simulation unit 170 (hereinafter also referred to as a "vibration control-compatible tool"). Information indicating the type of vibration control-compatible tool is stored in advance in the tool data storage unit 142 (Figure 3). If the vibration monitoring process is performed for a tool that is not vibration control-compatible, a NO determination is always made in S34 of Figure 8, and the simulation is not performed. In this embodiment, an end mill (e.g., a constant-pitch end mill) is registered as a vibration control-compatible tool. End mills are suitable for vibration simulations. However, the type of vibration control-compatible tool can be set arbitrarily. The control unit 4 may determine whether the second tool is a vibration control-compatible tool based on information (e.g., tool ID or model number) acquired by the reader 19 from the second tool information presentation unit.

If the second tool is not a vibration control compatible tool (NO in S72), processing flow F7 ends without executing S74 and subsequent steps. On the other hand, if the second tool is a vibration control compatible tool (YES in S72), processing proceeds to S74.

In S74, the control unit 4 determines whether the number of teeth estimation function is enabled. The machine tool 1 in this embodiment has the first number of teeth estimation function and the second number of teeth estimation function described below.

The first tooth count estimation function estimates the number of teeth of the second tool based on the appearance of the second tool. Specifically, the estimation unit 163 estimates the number of teeth of the second tool based on image information showing the appearance of the second tool acquired by the camera 55. The estimation unit 163 may estimate the number of teeth of the second tool based on a single image, or may estimate the number of teeth of the second tool based on multiple images.

The second tooth number estimation function estimates the number of teeth of the second tool based on the behavior of the second tool held by the spindle 18. Specifically, the estimation unit 163 estimates the cutting edge passing frequency of the second tool using vibration data of the second tool acquired by the acceleration sensor 30, and estimates the number of teeth of the second tool based on the estimated cutting edge passing frequency and the rotational speed of the spindle 18. The estimation unit 163 may calculate the number of teeth N of the second tool using the following equation (2):

N=F×60/n...(2)
In formula (2), "F" is the cutting edge passing frequency (Hz), and "n" is the spindle rotation speed (min ^-1 ). If the calculated value of "N" is not an integer, the estimation unit 163 may estimate the integer closest to the calculated value of "N" as the number of teeth of the second tool.

If at least one of the first and second tooth count estimation functions is normal, a YES determination is made in S74. If an abnormality has occurred in both the first and second tooth count estimation functions, a NO determination is made in S74. Note that it is not essential for a machine tool to have multiple tooth count estimation functions. For example, either the first tooth count estimation function or the second tooth count estimation function may be omitted. Furthermore, the control unit 4 according to this embodiment may be installed in a machine tool that does not have a tooth count estimation function implemented. In such a machine tool, a NO determination is always made in S74.

If the number of teeth estimation function is enabled (YES in S74), the control unit 4 estimates the number of teeth of the second tool using the enabled number of teeth estimation function in S75. If both the first and second number of teeth estimation functions are enabled, the control unit 4 (estimation unit 163) may estimate the number of teeth of the second tool using the simpler first number of teeth estimation function. When estimating the number of teeth of the second tool using the second number of teeth estimation function, the estimation unit 163 may wait until the processing device 2 to which the second tool is attached starts processing (cutting), and then perform number of teeth estimation during processing.

Once the estimation of the number of teeth (S75) is completed, the estimation unit 163 of the tool information management unit 160 sets the estimated number of teeth of the second tool in S76. Then, processing flow F7 ends. The estimation unit 163 may store the estimated number of teeth of the second tool in the tool data storage unit 142 (Figure 3) in association with the identification information and type of the second tool.

On the other hand, if the blade count estimation function is not enabled (NO in S74), the control unit 4 determines in S77 whether the notification control unit 156 is enabled. Specifically, if the notification flag is set to "disabled (0)," a NO determination is made in S77, and processing flow F7 ends. Also, if the notification flag is set to "enabled (1)," a YES determination is made in S77, and processing proceeds to S78.

In S78, the control unit 4 executes notification control to guide the user to input the number of teeth of the second tool. Specifically, the notification control unit 156 causes the operation panel 54 (display device 542) to display a second message screen including a message guiding the user to input (set) the number of teeth of the second tool. The second message screen may be displayed as a pop-up. FIG. 18 is a diagram showing an example of the second message screen. The message screen Sc6 shown in FIG. 18 includes identification information for the tool in use, a message indicating that the tool in use is compatible with the simulation function, a message guiding the operator to input the number of teeth of the second tool (for example, a message indicating that simulation-related settings enable simulation), and a message instructing the operator how to disable the notification (processing of S78). However, the content displayed on the second message screen can be changed as appropriate.

The processing of S78 above allows the operator to know the existence of the simulation unit 170. An operator who wants to use the simulation unit 170 is likely to follow the guidance of the second message screen and enter the number of teeth of the second tool in the tool management app (for example, the first setting screen Sc2 shown in FIG. 7). This allows for the vibration control app (simulation unit 170) to be utilized. When the processing of S78 is executed, the processing flow F7 (FIG. 17) ends with the second message screen still displayed. The control unit 4 ends the display of the second message screen in response to a user operation. The operator can end the display of the second message screen at any time. In this embodiment, the notification processing of S38 (FIG. 8) and the notification processing of S78 (FIG. 17) are enabled/disabled together using a common setting (see FIG. 15). However, each notification processing may be enabled/disabled separately using individual settings.

As described above, the machine tool 1 according to this embodiment includes a tool holder (spindle 18) that detachably holds a tool, and a control unit 4. The control unit 4 includes an estimation unit 163 (Figure 3) that estimates the number of teeth of the tool T attached to the spindle 18, and a simulation unit 170 (Figure 3) that uses the number of teeth to perform a simulation of the behavior (e.g., vibration) of the tool T held in the tool holder. The machine tool 1 can use a variety of tools. Therefore, information on all tools that can be used by the machine tool 1 is not pre-stored in the tool data storage unit 142. However, by including the estimation unit 163, the machine tool 1 can estimate the number of teeth of the tool T. This makes it easier to perform the above-mentioned simulation using the number of teeth. Such simulations contribute to supporting vibration countermeasures.

Furthermore, when the number of teeth of the tool T held in the tool holding unit is set, the simulation unit 170 calculates the recommended machining conditions for the tool T held in the tool holding unit by performing a simulation using the set number of teeth (see S11 and S12 in Figure 5 and S35 in Figure 8). When the machine tool 1 performs machining according to the recommended machining conditions calculated in this way, machining defects such as chatter vibration are less likely to occur.

Furthermore, when replacing the tool T held in the tool holding unit, the estimation unit 163 estimates the number of teeth of the replaced tool T based on at least one of the appearance and behavior of the replaced tool T. This configuration makes it easier to appropriately estimate the number of teeth of the tool T.

The estimation unit 163 according to the above embodiment estimates the number of teeth of the tool T when predetermined estimation conditions are met (S75 in FIG. 17). In detail, the predetermined estimation conditions include that the number of teeth of the replaced tool has not been set (first requirement: S71 in FIG. 17), that the replaced tool is a tool corresponding to the simulation unit 170 (second requirement: S72 in FIG. 17), and that the function for estimating the number of teeth of the tool T is enabled (third requirement: S74 in FIG. 17). This configuration makes it easier to estimate the number of teeth at the appropriate time.

In the above embodiment, the control unit 4 further includes a notification control unit 156 that executes notification control to guide the user to input the number of teeth of the tool T (Figure 3). If all of the above-mentioned first to third requirements (S71, S72, S74) are met, the estimation conditions are met, and the estimation unit 163 executes tooth count estimation (S75). On the other hand, if the estimation conditions are not met and predetermined notification conditions are met, the notification control unit 156 executes notification control (S78). In more detail, the predetermined notification conditions include the number of teeth of the replaced tool not being set (S71 in Figure 17), the replaced tool being a tool corresponding to the simulation unit 170 (S72 in Figure 17), the machine tool 1 not being equipped with or not enabled functionality for estimating the number of teeth of the tool T held in the tool holder (S74 in Figure 17), and the notification control unit 156 being enabled (S77 in Figure 17). With this configuration, when an estimation of the number of blades is not performed, the user can be prompted to set the number of blades as needed. This prevents the number of blades from being left unset, and promotes the use of simulations.

However, the estimation conditions and notification conditions can be changed as appropriate. For example, instead of processing flow F7 shown in Figure 17, processing flows F7A to F7D shown in Figures 19 to 22 may be used.

Figure 19 is a flowchart showing a first variant of the processing flow shown in Figure 17. In processing flow F7A according to the first variant, S77 in Figure 17 is omitted.

Figure 20 is a flowchart showing a second variant of the processing flow shown in Figure 17. In processing flow F7B according to the second variant, S72 in Figure 17 is omitted.

Figure 21 is a flowchart showing a third modified example of the processing flow shown in Figure 17. In processing flow F7C according to the third modified example, steps S72 and S77 in Figure 17 are omitted.

Figure 22 is a flowchart showing a fourth modified example of the processing flow shown in Figure 17. In processing flow F7D according to the fourth modified example, steps S72, S74, S77, and S78 in Figure 17 are omitted. The control unit 4 includes a setting unit (second setting unit 162) that sets the number of teeth of the tool T using information presented by an information presentation unit provided on the tool T (Figure 3). If the number of teeth of the replaced tool T is set by the second setting unit 162 (YES in S71), estimation of the number of teeth is not performed. On the other hand, if the number of teeth of the replaced tool T is not set by the second setting unit 162 (NO in S71), the estimation unit 163 estimates the number of teeth of the replaced tool T (S75), and the estimated number of teeth is set (S76). This configuration makes it easier to set the number of teeth of the replaced tool T.

The execution timing (trigger) of process flows F7 and F7A-F7D is not limited to tool change and can be changed as appropriate. For example, these process flows may be executed every time the machine tool system is started.

The simulation unit 170 may perform other simulations in addition to or instead of the vibration simulation described above. The simulations may be three-dimensional (3D) simulations.

The simulation unit 170 may use the number of teeth to perform a simulation for machine protection control (hereinafter also referred to as "MPC simulation"). For example, the simulation unit 170 uses the MPC simulation to look ahead (predict) the position of a moving tool, and if the predicted tool position is inappropriate, it changes the settings related to tool movement control (e.g., target position) or stops the tool movement. MPC simulation can reduce the possibility of the tool colliding with a jig or the like. By having the simulation unit 170 perform an MPC simulation using the number of teeth, it becomes possible to predict even the behavior (trajectory) of the cutting edge, improving prediction accuracy.

The simulation unit 170 may also perform a simulation for tool wear and/or workpiece surface roughness (hereinafter also referred to as a "machining simulation"). The number of teeth affects the contact state between the tool and workpiece, and tool wear and workpiece surface roughness change depending on the contact state between the tool and workpiece. By having the simulation unit 170 perform a machining simulation using the number of teeth, it becomes possible to simulate the contact state between the tool and workpiece with high accuracy, improving the estimation accuracy of tool wear and workpiece surface roughness.

In the above embodiment, a horizontal machining center was used as an example of the machine tool 1. However, the type of machine tool is arbitrary, and it may be a vertical machining center, a turning sensor, or a multi-tasking machine equipped with the functions of both a machining center and a turning center.

Figure 23 is a diagram showing a modified example of the machine tool shown in Figure 1. The machine tool 1A shown in Figure 23 has a PFM (Process Force Monitor) function. More specifically, the machine tool 1A includes a control unit 4A, servo drivers 211R, 211X, 211Y, and 211Z, servo motors 212R, 212X, 212Y, and 212Z, a movable body 213, a spindle head 231, a strain sensor 234, a table 236, and a tool T. The spindle head 231 includes a spindle 232 and a housing 233. The housing 233 houses the spindle 232. The spindle 232 detachably holds the tool T. The movable body 213 is attached to the spindle head 231.
The servo driver 211R sequentially receives the target rotation speed from the control unit 4A, and controls the servo motor 212R based on the target rotation speed. The servo motor 212R drives the main shaft 232 to rotate around the axis in the Z direction.

The spindle head 231 moves (displaces) together with the moving body 213. Each of the servo drivers 211X, 211Y, and 211Z sequentially receives a target position from the control unit 4A. The servo drivers 211X, 211Y, and 211Z sequentially receive feedback of the actual positions of the servo motors 212X, 212Y, and 212Z, respectively, and adjust the actual positions of the servo motors 212X, 212Y, and 212Z to approach the target positions. The servo motors 212X, 212Y, and 212Z each feed-drive the moving body 213 in the X, Y, and Z directions via, for example, a ball screw, thereby adjusting the spindle 232 to any position in the X, Y, or Z direction.

The workpiece W is fixed to the table 236. The control unit 4A controls the servo drivers 211R, 211X, 211Y, and 211Z in accordance with a machining program (e.g., an NC program) to move the tool T and machine the workpiece W with the tool T. The machining program may indicate the machining path of the tool T. For example, when the machine tool 1A cuts the workpiece W into a square, the tool T moves repeatedly along the same machining path (square path). The machine tool 1A may move the spindle head 231 slightly in the Z-axis direction each time the tool T completes one revolution of the machining path.

The strain sensor 234 detects the cutting force acting on the tool T held by the spindle 232 and outputs the detection result to the control unit 4A. The control unit 4A detects wear and/or damage to the tool T based on the cutting force waveform detected by the strain sensor 234. Specifically, the control unit 4A normalizes and phase-aligns the first cutting force waveform (reference waveform) and the second cutting force waveform at the same machining position before comparing them. The control unit 4A then detects how the cutting force has changed based on the comparison results, and detects wear and/or damage to the tool T based on the change in the cutting force waveform. Note that while only one strain sensor 234 is shown in Figure 23, the number of strain sensors is arbitrary and may be one or multiple (e.g., about four).

Figure 24 is a graph showing an example of the relationship between tool T breakage and cutting force. In the example shown in Figure 24, tool T is an end mill with a constant pitch, and the second cutting edge is broken. Waveform D110 (solid line) shows the cutting force before the breakage occurred. Waveform D120 (dashed line) shows the cutting force after the breakage occurred. The waveform in section P110 shows the cutting force waveform of the first cutting edge. The waveform in section P120 shows the cutting force waveform of the second cutting edge. Because the first cutting edge is not broken, there is no significant change in the cutting force waveform before and after the breakage occurred in section P110. In contrast, there is a significant change in the amplitude of the cutting force waveform before and after the breakage occurred in section P120. Comparing waveforms D110 and D120 in section P120, it can be seen that the cutting force applied to tool T is significantly reduced due to the breakage of the cutting edge.

As shown in FIG. 23, the control unit 4A includes an HMI processing unit 110, a data processing unit 112A, a data storage unit 114A, and a detection unit 116A. The data processing unit 112A includes a numerical control unit 150A, a notification control unit 156, a display control unit 158, a tool information management unit 160, and a simulation unit 170A. The basic configuration of the control unit 4A is the same as that of the control unit 4 shown in FIG. 3. However, the detection unit 116A detects the cutting force of the tool T based on the sensor output from the strain sensor 234. The simulation unit 170A performs a machining simulation using the set number of teeth. The numerical control unit 150A performs machining control corresponding to the machine tool 1A. The data storage unit 114A stores data corresponding to the machine tool 1A.

In response to the launch of a basic application, the control unit 4A executes processing flow F1 shown in FIG. 5. However, at S12 in FIG. 5, the control unit 4A executes processing flow F10, described below, instead of processing flow F3 (FIG. 8). FIG. 25 is a flowchart showing a modified example of the processing at S12 in FIG. 5.

In process flow F10 shown in FIG. 25, the control unit 4A (simulation section 170A) executes a machining simulation as a set job. In S110, the control unit 4A measures the first cutting force waveform (reference waveform). The control unit 4A repeatedly executes steps S120 to S170 until the simulation is complete (S115). For example, if the simulation includes a command to move the tool T ten times on the same machining path, the control unit 4A acquires the first cutting force waveform in the first machining run, and repeatedly executes steps S120 to S170 nine times in the second and subsequent machining runs.

In S120, the control unit 4A measures the waveform of the second cutting force. Next, in S125, the control unit 4A normalizes each waveform (the waveforms of the first and second cutting forces) and aligns the phases of each waveform. Next, in S130, the control unit 4A compares the cutting force for each blade in each waveform based on the set number of blades of the tool T.

Based on the set number of blades of tool T, the control unit 4A also repeatedly executes the processes of S140 to S165 for the number of blades (S135). In S140, the control unit 4A determines whether the cutting force of the blade of tool T has increased by a predetermined first threshold or more. More specifically, the control unit 4A compares the cutting force (amplitude) of a certain blade in the second cutting force waveform with the cutting force (amplitude) of a certain blade in the first cutting force waveform to obtain the difference. The control unit 4A determines whether the difference (increase in cutting force) is equal to or greater than the first threshold. If it is determined that the cutting force of the blade has increased by the first threshold or more (YES in S140), the process proceeds to S145; otherwise (NO in S140), the process proceeds to S150. In S145, the control unit 4A determines that the blade of tool T is worn.

In S150, the control unit 4A determines whether the cutting force of the blade of the tool T has decreased by a predetermined second threshold or more. More specifically, the control unit 4A compares the cutting force (amplitude) of a certain blade in the second cutting force waveform with the cutting force (amplitude) of a certain blade in the first cutting force waveform to obtain the difference. The control unit 4A determines whether the difference (amount of reduction in cutting force) is equal to or greater than the second threshold. If it is determined that the cutting force of the blade has decreased by the second threshold or more (YES in S150), processing proceeds to S155; otherwise (NO in S150), processing proceeds to S160. In S155, the control unit 4A determines that the blade of the tool T is chipped. In S160, the control unit 4A determines that there is no abnormality in the blade of the tool T.

In S165, the control unit 4A determines whether processing of all blades of tool T has been completed. If it is determined that processing of all blades of tool T has been completed (YES in S165), processing proceeds to S170; if not (NO in S165), processing returns to S115. In S170, the control unit 4A determines whether the simulation (job) has been completed. If it is determined that the simulation has been completed (YES in S170), processing flow F10 ends; if not (NO in S170), processing returns to S135.

In the machine tool 1A according to this modified example, when a tool T is replaced, if the number of teeth of the replaced tool T has not been set, the above-described process flow F10 (simulation) is not executed (see Figure 5). However, like the control unit 4 (Figure 1), the control unit 4A also executes process flow F2 (Figure 6) in response to user operation, and executes process flow F7 (Figure 17) when a tool is replaced. This prevents the number of teeth from remaining unset after a tool is replaced. Note that the content of the screen (Figure 7 or Figure 18) displayed in S12 in Figure 6 or S78 in Figure 17 is changed as appropriate to suit the machine tool 1A.

In the above embodiment, the adjustment process (Figure 16) is executed in response to a user operation (adjustment start operation). However, this is not limited to this, and the adjustment process (tuning process) of the machining conditions may be executed automatically when chatter vibration is detected. For example, when the simulation unit 170 detects chatter vibration, it may calculate recommended machining conditions using the number of teeth, and execute the adjustment process (Figure 16) of the machining conditions based on the calculated recommended machining conditions.

The embodiments disclosed herein should be considered in all respects to be illustrative and not restrictive. The scope of the present invention is indicated by the claims, not the above description, and is intended to include all modifications that are equivalent in meaning to and within the scope of the claims.

1, 1A Machine tool, 2 Machining device, 4, 4A Control unit, 18, 232 Spindle, 18a Rotation sensor, 18b Tool detection sensor, 19 Reader, 30 Acceleration sensor, 40 Signal processing device, 50 Control device, 52 Vibration processing device, 54 Operation panel, 55 Camera, 110 HMI processing unit, 112, 112A Data processing unit, 114, 114A Data storage unit, 116, 116A Detection unit, 150, 150A Numerical control unit, 156 Notification control unit, 158 Display control unit, 160 Tool information management unit, 161 First setting unit, 162 Second setting unit, 163 Estimation unit, 170, 170A Simulation unit, 171 Detection unit, 172 Recommended condition calculation unit, 173 Tuning management unit, 234 Strain sensor, T Tool, W Workpiece.

Claims (5)

a tool holding portion that detachably holds a tool;
an estimation unit that estimates the number of teeth of a tool attached to the tool holding unit;
a simulation unit that uses the number of teeth to perform a simulation regarding the behavior of the tool held by the tool holder;
A machine tool comprising: the machine tool further includes a setting unit that sets the number of teeth of the tool using information presented by an information presenting unit provided on the tool;
2. The machine tool according to claim 1, wherein, when the tool held in the tool holding unit is replaced, if the number of teeth of the replaced tool has not been set, the estimating unit is configured to estimate the number of teeth of the replaced tool. The machine tool according to claim 1, wherein the estimation unit is configured, when replacing a tool held in the tool holding unit, to estimate the number of teeth of the replaced tool based on at least one of the appearance and behavior of the replaced tool. the estimation unit is configured to estimate the number of teeth of a tool when a predetermined estimation condition is met,
The predetermined estimation condition is:
The number of teeth of the tool after replacement is not set,
The replaced tool is a tool corresponding to the simulation unit; and
and
2. The machine tool according to claim 1, further comprising a notification control unit that executes notification control to guide a user to input the number of tool teeth when the predetermined estimation condition is not met and a predetermined notification condition is met. The machine tool described in any one of claims 1 to 4, wherein the simulation unit is configured to, when the number of flutes of the tool held in the tool holding unit is set, calculate recommended machining conditions for the tool held in the tool holding unit by performing the simulation using the set number of flutes.