JP7724133B2 - Grinding System - Google Patents

Description

The present invention relates to a grinding system.

Grinding is performed, for example, by bringing a rapidly rotating grinding wheel into contact with a rotating workpiece. Therefore, in grinding, it is important to manage the condition of the grinding wheel in order to maintain the grinding accuracy of the workpiece. For this reason, Patent Documents 1 to 3 have previously disclosed techniques for managing the condition of the grinding wheel based on the processing state when the workpiece is ground by the grinding wheel.

Japanese Patent Application Laid-Open No. 2017-151962 Japanese Patent Application Laid-Open No. 2020-23040 Japanese Patent Application Laid-Open No. 2020-15129

However, when evaluating the processing state and managing the condition of the grinding wheel based on the evaluation results, it is at least necessary to be able to obtain the evaluation results. Therefore, if the evaluation results cannot be obtained, especially if they are not obtained unintentionally, it is impossible to grasp the condition of the grinding wheel. As a result, there is a risk that grinding will continue in a deteriorated state with the grinding wheel.

The present invention was made in consideration of these issues, and aims to provide a grinding system that is capable of performing good grinding even when evaluation results cannot be obtained unintentionally.

One aspect of the present invention is a grinding machine comprising: a grinding machine body that performs grinding processing on a workpiece using a grinding wheel;
an observation device provided on the grinding machine body for detecting measurement data observed during grinding in order to observe a processing state of the workpiece during grinding by the grinding machine body;
a control device that counts the number of grinding processes that indicates the number of times the grinding process has been performed by the grinding machine body and controls the operation of the grinding machine body;
a machining state evaluation device that performs evaluation processing for evaluation items related to the machining state when the grinding machine main body grinds the workpiece based on the measurement data detected by the observation device , and outputs evaluation signals related to the evaluation results of the evaluation items to the control device;
Equipped with
the machining state evaluation device is set to perform the evaluation process for each grinding cycle,
The control device
When the evaluation signal can be acquired from the processing state evaluation device, if the evaluation result of the evaluation signal acquired from the processing state evaluation device indicates that a sign of deterioration in the grinding processing state by the grinding wheel has occurred, a sign management process is performed to cause the grinding machine main body to perform a correction process for the grinding wheel;
In the grinding system, if the evaluation signal cannot be acquired from the processing state evaluation device despite being set to acquire the evaluation signal from the processing state evaluation device, a number management process is performed in which the grinding machine main body performs the correction process on the grinding wheel when the number of grinding processes reaches a specified number.

When the control device is able to receive an evaluation signal from the machining state evaluation device, it performs symptom management processing. Symptom management processing is a process that causes the grinding machine body to perform grinding wheel correction processing when the evaluation result of the evaluation signal received from the machining state evaluation device indicates that a symptom of deterioration in the grinding state by the grinding wheel has occurred. In this way, by performing grinding wheel correction processing before the grinding state deteriorates, it is possible to prevent deterioration of the grinding state. This allows the workpiece to continue to be ground with high precision.

Furthermore, when symptom management processing is being performed, grinding wheel correction processing can be performed when it is determined that a symptom of a deterioration in the grinding condition has occurred, rather than when the number of times the workpiece has been ground reaches a specified number. Therefore, even if the number of times the workpiece has been ground exceeds the specified number, grinding processing can continue without grinding wheel correction processing. This makes it possible to lengthen the interval between grinding wheel correction processing (the number of grinding operations between the previous correction processing and the next correction processing). This therefore contributes to extending the life of the grinding wheel.

However, symptom management processing by the control device requires acquisition of an evaluation signal from the machining state evaluation device. The control device may unintentionally be unable to acquire the evaluation signal, for example, if the power supply to the machining state evaluation device is cut off (power outage) or communication is disrupted. In this way, when the control device is unable to acquire the evaluation signal from the machining state evaluation device, the control device performs count management processing. Count management processing is a process that causes the grinding machine body to perform grinding wheel correction processing when the number of grinding operations reaches a specified number. In other words, when symptom management processing cannot be performed, the control device can maintain the condition of the grinding wheel in good condition by performing count management processing. As a result, deterioration in the grinding accuracy of the workpiece can be prevented.

As described above, the above aspect provides a grinding system that can perform good grinding even when evaluation results cannot be obtained unintentionally.

1 is a plan view showing a configuration of a grinding system according to a first embodiment. FIG. 2 is a diagram illustrating a configuration of the control device of FIG. 1. 3 is a diagram showing the contents of a symptom management command issued by a symptom management processing unit constituting the control device of FIG. 2. FIG. 10 is a flowchart showing a process performed by the machining state evaluation device of the second embodiment. FIG. 10 is a diagram illustrating the configuration of a control device according to a third embodiment. FIG. 10 is a diagram illustrating the configuration of a control device according to a fourth embodiment. 10 is a diagram showing the contents of a symptom management command issued by a symptom management processing unit constituting the control device of embodiment 4. FIG.

(Embodiment 1)
1. Overview of Grinding System 1 The grinding system 1 of this embodiment will be described with reference to Fig. 1. As shown in Fig. 1, the grinding system 1 includes a grinding machine 2, an observation device 3, and a machining state evaluation device 4. The grinding machine 2 rotates the workpiece W and also rotates the grinding wheel T, thereby moving the workpiece W and the grinding wheel T relative to each other, thereby grinding the workpiece W with the grinding wheel T. The grinding machine 2 can be configured in various ways, such as a cylindrical grinding machine, a cam grinding machine, or a surface grinding machine.

The observation device 3 is a device that observes the state of grinding performed by the grinding machine 2. The observation device 3 is provided on the grinding machine 2 to observe the state of grinding performed by the grinding machine 2. The observation device 3 can be, for example, a sensor that acquires the operation of the components that make up the grinding machine 2 during grinding, a sensor that acquires grinding sounds generated during grinding, or a sensor that acquires surface images of the grinding wheel T or workpiece W.

The machining state evaluation device 4 evaluates multiple evaluation items related to the grinding state of the grinding machine 2 based on measurement data observed by the observation device 3 while the grinding machine 2 is grinding the workpiece W. The machining state evaluation device 4 then outputs the evaluation results of the multiple evaluation items to the grinding machine 2. In this embodiment, the machining state evaluation device 4 communicates with the grinding machine 2 to output evaluation signals S each including the evaluation results of the multiple evaluation items.

In addition, if the grinding accuracy of the workpiece W decreases due to the condition of the grinding wheel T, the grinding machine 2 performs a correction process on the grinding wheel T. Specifically, the grinding machine 2 performs a dressing operation to sharpen the grinding wheel T.

The grinding machine 2 then determines the timing of performing the dressing operation based on the evaluation result of the evaluation signal S obtained from the processing state evaluation device 4. Specifically, the grinding machine 2 performs the dressing operation when the evaluation result of the evaluation signal S obtained from the processing state evaluation device 4 indicates that there are signs of deterioration in the grinding processing state by the grinding wheel T.

However, the grinding machine 2 can only determine the timing to perform the dressing operation based on the evaluation results if the grinding machine 2 can acquire the evaluation signal S from the machining state evaluation device 4. However, there is a risk that the grinding machine 2 may unintentionally be unable to acquire the evaluation signal S, such as when the power supply to the machining state evaluation device 4 is cut off (power outage) or when communication is interrupted. In such cases, the grinding machine 2 will not be able to acquire the evaluation signal S from the machining state evaluation device 4.

Therefore, if the grinding machine 2 cannot obtain the evaluation signal S from the machining state evaluation device 4, it will perform processing without using the evaluation signal S. Specifically, the grinding machine 2 will perform a dressing operation when the number of grinding operations reaches a specified number.

In Figure 1, the grinding system 1 is shown as an example in which one machining state evaluation device 4 is provided for one grinding machine 2. This configuration allows for high-speed communication between the grinding machine 2 and the machining state evaluation device 4. However, the grinding system 1 may also be configured so that one machining state evaluation device 4 is capable of communicating with multiple grinding machines 2. In this case, the machining state evaluation device 4 can be provided in, for example, a server device. In other words, the machining state evaluation device 4 and multiple grinding machines 2 are configured to form a network.

2. Configuration of Grinding Machine 2 The configuration of the grinding machine 2 will be described with reference to Fig. 1. The grinding machine 2 includes a grinding machine main body 10, an operation panel 20, and a control device 30. The grinding machine main body 10 grinds a workpiece W using a grinding wheel T. In detail, the grinding machine main body 10 rotatably supports the workpiece W, and is configured to be able to grind the workpiece W by relatively moving the workpiece W and the grinding wheel T toward and away from each other while the grinding wheel T is rotating.

In this embodiment, the grinding machine body 10 is a cylindrical grinding machine, and a wheelhead traverse type grinding machine is used as an example. However, the grinding machine body 10 can also be a table traverse type grinding machine, or a grinding machine other than a cylindrical grinding machine. The grinding machine body 10 in this embodiment includes a bed 11, a headstock 12, a tailstock 13, a traverse base 14, a wheelhead 15, a sizing device 16, and a grinding wheel dressing device 17.

The bed 11 is placed on an installation surface. The headstock 12 is placed on the top surface of the bed 11, at the front side in the X-axis direction (lower side in Figure 1), which is the front side of the machine, and at one end side in the Z-axis direction, which is the left side of the machine (left side in Figure 1). The headstock 12 supports one axial end of the workpiece W, and supports the workpiece W rotatably around the Z-axis. Furthermore, the headstock 12 drives the motor 12a provided on the headstock 12 to rotate the workpiece W around the Z-axis.

The tailstock 13 is located on the top surface of the bed 11, facing the headstock 12 in the Z-axis direction. That is, the tailstock 13 is located on the near side in the X-axis direction (bottom side in Figure 1), which is the front of the machine, and on the other end side in the Z-axis direction, which is the right side of the machine (right side in Figure 2). The tailstock 13 supports the other axial end of the workpiece W, and supports the workpiece W rotatably around the Z-axis. Therefore, the workpiece W is rotatably supported at both ends by the headstock 12 and tailstock 13. Note that the workpiece W may also be cantilevered by the headstock 12 alone.

The traverse base 14 is disposed on the upper surface of the bed 11 so as to be movable in the Z-axis direction. The traverse base 14 is moved by driving a motor 14a provided on the bed 11. The grinding wheel head 15 is disposed on the upper surface of the traverse base 14 so as to be movable in the X-axis direction. The grinding wheel head 15 is moved by driving a motor 15a provided on the traverse base 14. The grinding wheel head 15 is equipped with a rotatable grinding wheel T. The grinding wheel T rotates by driving a motor 15b provided on the grinding wheel head 15. The grinding wheel T is composed of multiple abrasive grains fixed together with a binder.

The sizing device 16 measures the dimensions (diameter) of the workpiece W. The sizing device 16 is mounted on the upper surface of the bed 11 so that it can move in the Z-axis direction. The position of the sizing device 16 in the Z-axis direction is controlled by a feed mechanism 16a mounted on the bed 11.

The grinding wheel dressing device 17 is a device for adjusting the shape of the grinding wheel T. In other words, the grinding wheel dressing device 17 is a device for truing and dressing the grinding wheel T. The grinding wheel dressing device 17 can be, for example, a rotary dresser or a single-stone dresser. In Figure 1, the grinding wheel dressing device 17 is shown as a rotary dresser.

Here, truing is the process of reshaping the grinding wheel T. Truing is the process of shaping the grinding wheel T to fit the shape of the workpiece W when the grinding wheel T has become worn, worn out, or has lost or broken abrasive grains due to grinding, and the process of removing runout of the grinding wheel T due to uneven wear. Dressing is the process of dressing the grinding wheel T, adjusting the amount of protrusion of the abrasive grains, and creating cutting edges for the abrasive grains. In other words, the dressing operation is the process of correcting dullness, clogging, and missing grains.

The operation panel 20 is an input device that allows the operator to perform various input processes. For example, input operations on the operation panel 20 allow the input of machining programs, various parameters, etc. The operation panel 20 is also equipped with a display device that can display information input by the operator, the status of the grinding machine main body 10, etc.

The control device 30 acquires the machining program and various information input via the operation panel 20, as well as detection information from the various sensors that make up the grinding machine body 10. The control device 30 then controls the operation of the grinding machine body 10 based on the acquired machining program and detection information from the various sensors that make up the grinding machine body 10. In particular, the control device 30 controls each drive device that makes up the grinding machine body 10.

The control device 30 then controls the grinding machine main body 10 to execute a grinding cycle for the workpiece W. For example, one grinding cycle is the process of grinding one workpiece W. In other words, the control device 30 repeatedly executes the grinding cycle, causing the grinding machine main body 10 to grind multiple workpieces W. The control device 30 also controls the display of various information on the display device of the operation panel 20.

Furthermore, the control device 30 acquires an evaluation signal S from the machining state evaluation device 4. Based on the evaluation signal S, the control device 30 performs adjustment processing for the grinding wheel T, particularly management processing for the timing of performing the dressing operation. In other words, the control device 30 determines the timing for performing the dressing operation for the grinding wheel T, and when the time to perform the dressing operation arrives, causes the grinding machine main body 10 to perform the dressing operation.

However, there are cases where the control device 30 is unable to obtain the evaluation signal S from the machining state evaluation device 4. For such cases, the control device 30 causes the grinding machine body 10 to perform a dressing operation on the grinding wheel T when the grinding process count, which indicates the number of grinding processes performed by the grinding machine body 10, reaches a specified number. To do this, the control device 30 counts the grinding process count. The grinding process count is the number of times a grinding process cycle has been performed, and in particular, the control device 30 counts the number of times a grinding process cycle has been performed since the previous dressing operation of the grinding wheel T was performed up to the present. When a dressing operation of the grinding wheel T is performed, the grinding process count is reset.

3. Observation equipment 3
The observation device 3 will be described with reference to Fig. 1. The observation device 3 is provided on the grinding machine body 10 in order to observe the state of grinding by the grinding machine 2. In this embodiment, the observation device 3 detects observation data related to the operation of the members constituting the grinding machine 2 as a physical quantity representing the state of grinding. For example, the observation data may be the acceleration of vibrations generated in response to the surface state of the workpiece W, the displacement (amplitude) of vibrations, etc. In this case, the observation device 3 may measure the measurement data by directly or indirectly contacting the workpiece W, or may estimate the measurement data without contacting the workpiece W.

In particular, in this embodiment, one of the observation devices 3 is an acceleration sensor provided on the tailstock 13 of the grinding machine body 10, as shown in FIG. 1. The acceleration sensor serving as one of the observation devices 3 detects, for example, the acceleration of vibrations of the tailstock 13 observed during grinding of the workpiece W. The acceleration sensor serving as one of the observation devices 3 outputs the acceleration data of the detected vibrations to the machining state evaluation device 4 as measurement data D.

The other observation device 3 is a sizing device 16 that constitutes the grinding machine main body 10. The sizing device 16, which is another observation device 3, acquires outer diameter data or surface shape data of the measured workpiece W. The sizing device 16 outputs the acquired outer diameter data or surface shape data as measurement data D to the machining state evaluation device 4. The observation device 3 may be configured to output to the machining state evaluation device 4 via the control device 30, or may be configured to output directly to the machining state evaluation device 4.

4. Detailed Configuration of Machining State Evaluation Device 4 The detailed configuration of the machining state evaluation device 4 will be described with reference to Fig. 1 and Fig. 2. In this embodiment, as shown in Fig. 1, the machining state evaluation device 4 functions as an edge computer provided corresponding to one grinding machine 2, and is capable of realizing high-speed calculation processing. The machining state evaluation device 4 is provided with a communication device independent of the control device 30 of the grinding machine 2, and is configured to be able to communicate with the control device 30. In addition, the machining state evaluation device 4 is provided with a power supply circuit independent of the grinding machine 2.

The machining state evaluation device 4 acquires measurement data D from the observation device 3. Then, based on the acquired measurement data D, the machining state evaluation device 4 performs evaluation processing for multiple evaluation items related to the machining state of the grinding machine body 10 when the grinding machine body 10 grinds the workpiece W. The machining state evaluation device 4 outputs an evaluation signal S related to the evaluation results of the evaluation items to the control device 30.

In this embodiment, the multiple evaluation items can be appropriately selected from, for example, the presence or absence of chatter generated by the grinding process, the degree of chatter, the presence or absence of grinding burns, the surface roughness of the ground surface of the workpiece W, and the shape of the workpiece W. The machining state evaluation device 4 then performs evaluation processing for each evaluation item and outputs an evaluation signal S relating to the evaluation result of each evaluation item to the control device 30 via communication.

As shown in FIG. 2, the machining state evaluation device 4 performs evaluation processing for, for example, four evaluation items. In this embodiment, "Evaluation Item 1" is the presence or absence of chatter that occurs during grinding, "Evaluation Item 2" is the presence or absence of grinding burns, "Evaluation Item 3" is the surface roughness of the workpiece W, and "Evaluation Item 4" is the shape of the workpiece W.

The processing state evaluation device 4 also generates evaluation results for each of "Evaluation Item 1" to "Evaluation Item 4" using one of four levels: "Good," "Bad," "Warning," or "Fail." The evaluation result "Good" indicates that the state of the evaluation item is good. The evaluation result "Bad" indicates that the state of the evaluation item is bad. The evaluation result "Warning" indicates that there are signs of a deterioration in the grinding processing state caused by the grinding wheel T. In other words, the evaluation result "Warning" indicates that a defect may occur as the state of the grinding wheel T deteriorates. The evaluation result "Failure" indicates that the evaluation itself has failed. Examples of evaluation failures include when an evaluation result cannot be generated or when an abnormal value that does not exist as a normal evaluation result is output.

The machining state evaluation device 4 estimates and determines the level of chatter, grinding burn, and surface roughness, for example, based on the vibration of the tailstock 13 in the measurement data D, and outputs an evaluation signal S containing the evaluation results to the control device 30 of the grinding machine 2. The machining state evaluation device 4 also determines the presence or absence of grinding burn and the level of the shape of the workpiece W, for example, based on the vibration of the tailstock 13 and the outer diameter of the workpiece W in the measurement data D, and outputs an evaluation signal S containing the evaluation results to the control device 30 of the grinding machine 2.

In addition, the types of evaluation results for each evaluation item in the processing state evaluation device 4 are not limited to the four types mentioned above, and can be set arbitrarily. However, the types of evaluation results must at least include "Warning."

In addition, in this embodiment, the machining state evaluation device 4 can perform evaluation processing, for example, after each grinding cycle. In other words, the machining state evaluation device 4 performs evaluation processing for each of "Evaluation Item 1" to "Evaluation Item 4" for all workpieces W and generates evaluation results. The machining state evaluation device 4 then outputs the evaluation results to the control device 30 before grinding of the next workpiece W begins.

Here, if the workpiece W has one grinding location, one grinding cycle is the process of grinding one grinding location on one workpiece W. In this case, after the one grinding cycle is completed, the processing state evaluation device 4 performs an evaluation process for that grinding location.

Furthermore, for example, in a workpiece W having multiple journal portions, such as a crankshaft or camshaft, similar grinding may be performed on each of the multiple journal portions. When a workpiece W has multiple grinding locations of the same type, such as multiple journal portions, one grinding cycle is a process of grinding multiple grinding locations on one workpiece W. In this case, after the completion of one grinding cycle, the machining state evaluation device 4 may perform evaluation processing on the multiple grinding locations.

In addition, evaluation processing can be performed on some of the grinding areas that have already been ground during a single grinding cycle in which multiple grinding areas of the same type are to be ground. In this case, evaluation processing can be performed while grinding is being performed on the remaining grinding areas on the workpiece W, and the evaluation processing can be completed before the end of one grinding cycle.

5. Detailed Configuration of the Control Device 30 Related to Grinding Wheel Correction Processing Of the configuration of the control device 30, functions related to grinding wheel correction processing will be described with reference to Figures 2 and 3. The control device 30 is composed of a PLC (Programmable Logic Controller) 31 and a CNC (Computerized Numerical Control) device 32.

The PLC 31 communicates with the machining state evaluation device 4 to obtain an evaluation signal S from the machining state evaluation device 4. Based on the evaluation signal S, the PLC 31 determines whether or not to dress the grinding wheel T. When the CNC device 32 receives a command from the PLC 31 to dress the grinding wheel T, it causes the grinding machine main body 10 to perform a dressing operation on the grinding wheel T.

As shown in FIG. 2, the PLC 31 includes a signal acquisition unit 41, an evaluation item setting unit 42, an evaluation item validity determination unit 43, an evaluation signal acquisition determination unit 44, and an output unit 45.

The signal acquisition unit 41 acquires the evaluation signal S output from the processing state evaluation device 4. That is, the signal acquisition unit 41 acquires the evaluation signal S related to the evaluation results of the evaluation items evaluated by the processing state evaluation device 4. In this embodiment, the processing state evaluation device 4 outputs an evaluation signal S related to the evaluation results of each of the multiple evaluation items. Therefore, the signal acquisition unit 41 is configured to be able to acquire the evaluation signal S related to the evaluation results of each of the multiple evaluation items output from the processing state evaluation device 4. When the signal acquisition unit 41 acquires each evaluation signal S from the processing state evaluation device 4, it turns "signal ON" for each evaluation item, for example, by ladder logic, and then switches to "signal OFF."

The evaluation item setting unit 42 sets whether or not evaluation items to be acquired from the processing state evaluation device 4 are necessary, among multiple evaluation items. That is, the evaluation item setting unit 42 sets evaluation items to be acquired from the processing state evaluation device 4 as "enabled," and sets evaluation items not to be acquired (unnecessary) as "disabled."

The evaluation item setting unit 42 may, for example, allow the operator to arbitrarily set "enabled" or "disabled" for required evaluation items in advance, or may set "enabled" or "disabled" according to the evaluation items in the evaluation signal S acquired by the signal acquisition unit 41. In this embodiment, the evaluation item setting unit 42 may, as shown in FIG. 2, set "enabled" or "disabled" for each of "Evaluation Item 1" to "Evaluation Item 4." "Evaluation Item 1," "Evaluation Item 2," and "Evaluation Item 4" are set to "enabled," and "Evaluation Item 3" is set to "disabled."

The signal acquisition unit 41 acquires evaluation signals S for evaluation items set to "enabled" by the evaluation item setting unit 42. On the other hand, the signal acquisition unit 41 does not acquire evaluation signals S for evaluation items set to "disabled" by the evaluation item setting unit 42. In FIG. 2, the signal acquisition unit 41 acquires evaluation signals S for "Evaluation Item 1," "Evaluation Item 2," and "Evaluation Item 4," but does not acquire an evaluation signal S for "Evaluation Item 3." Then, if the signal acquisition unit 41 has acquired evaluation signals S for each of the three evaluation items that it should acquire, it switches the state of each evaluation item to "signal ON."

The evaluation item validity determination unit 43 checks the setting status of the evaluation item setting unit 42. Then, the evaluation item validity determination unit 43 determines "Yes" if the setting status of the evaluation item setting unit 42 is such that at least one of "Evaluation Item 1" to "Evaluation Item 4" is set to "Valid." On the other hand, the evaluation item validity determination unit 43 determines "No" if the setting status of the evaluation item setting unit 42 is such that all of "Evaluation Item 1" to "Evaluation Item 4" are set to "Invalid."

When the evaluation item validity determination unit 43 determines that at least one of "Evaluation Item 1" to "Evaluation Item 4" is set to "valid" as the setting status of the evaluation item setting unit 42, the evaluation signal acquisition determination unit 44 determines whether the evaluation signal S for the evaluation item set to "valid" has been switched to "signal ON" by the signal acquisition unit 41. In other words, the evaluation signal acquisition determination unit 44 determines whether an evaluation signal S relating to the evaluation result has been acquired from the processing state evaluation device 4 for the evaluation item set to "valid" in the evaluation item setting unit 42.

As described above, after performing the evaluation process, the processing state evaluation device 4 outputs an evaluation signal S relating to the evaluation results to the PLC 31 of the control device 30 via communication. The signal acquisition unit 41 of the PLC 31 acquires, via communication, the evaluation signal S relating to the evaluation item set to "enabled" in the evaluation item setting unit 42. In this case, upon acquiring the evaluation signal S, the signal acquisition unit 41 switches from "signal OFF" to "signal ON."

However, if the communication between the control device 30 and the machining state evaluation device 4 deteriorates, or if the power supply to the machining state evaluation device 4 is cut off due to a power outage, etc., the machining state evaluation device 4 cannot send the evaluation signal S to the control device 30. In this case, the signal acquisition unit 41 of the PLC 31 cannot switch the evaluation signal S for evaluation items set to "enabled" from "signal OFF" to "signal ON."

The evaluation signal acquisition determination unit 44 determines "Yes" if the signal is switched to "Signal ON." That is, the evaluation signal acquisition determination unit 44 determines "Yes" if all evaluation signals S have been acquired from the machining state evaluation device 4 for evaluation items set to "enabled" in the evaluation item setting unit 42. On the other hand, the evaluation signal acquisition determination unit 44 determines "No" if the signal is "Signal OFF." That is, the evaluation signal acquisition determination unit 44 determines "No" if no evaluation signal S has been acquired from the machining state evaluation device 4 for evaluation items set to "enabled" in the evaluation item setting unit 42. Note that the evaluation signal acquisition determination unit 44 determines "No" if even one of the multiple evaluation items that should be acquired cannot be acquired.

The output unit 45 selects and performs one of the symptom management process and the number management process based on the judgment results of the evaluation item validity judgment unit 43 and the evaluation signal acquisition judgment unit 44. The output unit 45 generates a command based on the selected management process and outputs the generated command to the CNC device 32. The command here is mainly a command to the grinding machine body 10 regarding the execution of a dressing operation.

The output unit 45 includes a symptom management processing unit 45a that performs symptom management processing, and a count management processing unit 45b that performs count management processing. The symptom management processing is processing that causes the grinding machine main body 10 to perform a dressing operation on the grinding wheel T when it is determined that a symptom of deterioration in the grinding processing state by the grinding wheel T has occurred. However, the symptom management processing can also include other processing. The count management processing is processing that causes the grinding machine main body 10 to perform a dressing operation on the grinding wheel T when the grinding processing count, which indicates the number of grinding processing times performed by the grinding machine main body 10, reaches a specified count.

The symptom management processing unit 45a of the output unit 45 executes symptom management processing when the evaluation item validity determination unit 43 determines that at least one of the multiple evaluation items is set to "valid" and the evaluation signal acquisition determination unit 44 determines that the signal has been switched to "signal ON." In other words, when the signal acquisition unit 41 can acquire an evaluation signal S related to the evaluation results of the acquired and set evaluation items from the machining state evaluation device 4, the symptom management processing unit 45a executes symptom management processing based on the evaluation results of the acquired evaluation signal S. By executing symptom management processing, the symptom management processing unit 45a outputs a symptom management command R1 to the CNC device 32.

The symptom management command R1 will be described with reference to Figure 3. The symptom management command R1 includes a first command R11, a second command R12, a third command R13, and a fourth command R14. In other words, the symptom management processing unit 45a executes symptom management processing to determine one of the commands R11 to R14 included in the symptom management command R1, and outputs the determined symptom management command R1 to the CNC device 32.

As shown in Figure 3, each of the commands R11 to R14 in the symptom management command R1 is set according to the evaluation result of the evaluation signal S acquired by the signal acquisition unit 41. As mentioned above, there are four levels of evaluation results: "Good," "Bad," "Warning," and "Failure." Therefore, each of the commands R11 to R14 is set as a command corresponding to each of the four levels.

The first command R11 is a command that is determined when the evaluation result is "good." The first command R11 is a command to lengthen the interval between dressings of the grinding wheel T by the grinding wheel dressing device 17 (extending the dressing life). In other words, the first command R11 is a command to the grinding machine main body 10 not to perform the dressing operation of the grinding wheel T. If the evaluation result is "good," it is determined that there is no need to dress the grinding wheel T, and therefore the first command R11 is set as described above. Furthermore, the first command R11 includes a command to display "Evaluation result: good" on the display device of the operation panel 20.

The second command R12 is a command that is determined when the evaluation result is "bad." If the evaluation result is "bad," continuing grinding of the workpiece W may result in the production of another defective workpiece W. Therefore, the second command R12 is a command to stop the grinding cycle for the next workpiece W. In other words, the second command R12 is a command to stop grinding of the workpiece W by the grinding machine main body 10. Furthermore, the second command R12 includes a command to display "Evaluation result: bad" on the display device of the operation panel 20. The second command R12 can also perform processing to inform external devices such as the management device or the terminals of the manager and worker that the evaluation result is "bad."

The third command R13 is a command that is determined when the evaluation result is "Warning." In other words, the third command R13 is a command that is determined when there are signs of deterioration in the grinding processing condition. When there are signs of deterioration in the grinding processing condition, it means that the target evaluation item is not defective but is approaching defective. Therefore, the third command R13 is a command to cause the grinding machine main body 10 to perform a dressing operation of the grinding wheel T. Furthermore, the third command R13 includes a command to display "Evaluation result: Warning" on the display device of the operation panel 20. The number of grinding operations since the previous dressing operation can also be added to the display content. The third command R13 can also perform processing to notify external devices such as the management device or the manager's or worker's terminal that the evaluation result is "Warning." The number of grinding operations since the previous dressing operation can also be added to the display content.

The fourth command R14 is a command that is determined when the evaluation result is "failure." If the evaluation result is "failure," the evaluation process was not performed properly, meaning that the machining state cannot even be evaluated. Continuing to grind the workpiece W in this state could result in the production of a defective workpiece W. Therefore, the fourth command R14 is a command to stop the grinding cycle for the next workpiece W. In other words, the fourth command R14 is a command to stop the grinding of the workpiece W by the grinding machine main body 10. Furthermore, the fourth command R14 includes a command to display "Evaluation result: Fail" on the display device of the operation panel 20. The fourth command R14 can also perform processing to inform external devices, such as the management device or the manager's or worker's terminal, that the evaluation result is "failure."

The count management processing unit 45b of the output unit 45 executes count management processing when the evaluation item validity determination unit 43 determines that all evaluation items are set to "invalid," i.e., when all evaluation items are set to not require acquisition. Furthermore, the count management processing unit 45b executes count management processing when the evaluation signal acquisition determination unit 44 determines that the signal has not been switched to "signal ON." In other words, if the signal acquisition unit 41 cannot acquire an evaluation signal S related to the evaluation results of the evaluation items that have been set to acquire from the machining state evaluation device 4, the count management processing unit 45b executes count management processing. By executing count management processing, the count management processing unit 45b outputs a count management command R2 to the CNC device 32.

The count management process is a process for causing the grinding machine body 10 to perform a dressing operation on the grinding wheel T when the grinding process count, which indicates the number of grinding processes performed by the grinding machine body 10, reaches a specified count. The count management processing unit 45b then acquires the number of grinding processes since the previous dressing operation and determines whether the acquired number of grinding processes has reached the stored specified count. When the grinding process count reaches the specified count, the count management processing unit 45b outputs a count management command R2 to the CNC device 32 to cause the grinding wheel T to perform a dressing operation.

On the other hand, if the number of grinding operations has not reached the specified number, the number management processing unit 45b outputs a number management command R2 to the CNC device 32 to prevent the dressing operation of the grinding wheel T. Note that the number management processing unit 45b can also choose not to output any command to the CNC device 32 if the number of grinding operations has not reached the specified number.

Furthermore, the number of times management command R2 output by the number of times management processing unit 45b may include a command to display "number of times management" on the display device of the operation panel 20. The number of times management command R2 can also perform processing to instruct external devices such as the management device or the manager's or worker's terminal to perform number of times management processing.

Here, while symptom management processing is being performed by the symptom management processing unit 45a, the signal acquisition unit 41 may be unable to acquire the evaluation signal S from the machining state evaluation device 4, for example, due to a communication interruption. Then, when the symptom management processing continues to determine the first command R11, which is to extend the life of the dressing, the number of grinding operations may have already exceeded the specified number.

Therefore, if the symptom management process is performed and the number of grinding operations exceeds the specified number, and the signal acquisition unit 41 is unable to acquire the evaluation signal S from the machining state evaluation device 4, the number management processing unit 45b determines that the number of grinding operations has reached the specified number, and outputs a number management command R2 to the CNC device 32 to cause the grinding machine main body 10 to perform a dressing operation on the grinding wheel T.

When commands R11 to R14 are output by the symptom management processing unit 45a of the output unit 45 of the PLC 31, the CNC device 32 controls the grinding machine body 10 based on the output commands R11 to R14.

When a first command R11 is output from the symptom management processing unit 45a of the output unit 45, the CNC unit 32 performs dressing life extension and displays a screen. Furthermore, when a second command R12 is output from the symptom management processing unit 45a of the output unit 45, the CNC unit 32 stops the next grinding cycle and displays a screen. When a third command R13 is output from the symptom management processing unit 45a of the output unit 45, the CNC unit 32 performs a dressing operation and displays a screen. When a fourth command R14 is output from the symptom management processing unit 45a of the output unit 45, the CNC unit 32 stops the next grinding cycle and displays a screen.

6. Effects As described above, the control device 30 performs symptom management processing when it can acquire the evaluation signal S from the machining state evaluation device 4. The symptom management processing is processing in which the grinding machine main body 10 performs a dressing operation of the grinding wheel T when the evaluation result of the evaluation signal S acquired from the machining state evaluation device 4 indicates that a symptom of deterioration in the grinding processing state by the grinding wheel T has occurred.

In particular, when the evaluation result of the evaluation signal S obtained from the machining state evaluation device 4 indicates that a sign of deterioration in the grinding state by the grinding wheel T has occurred, the control device 30 executes the command content of the third command R13 of the sign management command R1. In other words, the control device 30 causes the grinding machine main body 10 to perform a dressing operation on the grinding wheel T based on the evaluation result of the evaluation signal S. In this way, by performing correction processing on the grinding wheel T at a stage before the grinding state deteriorates, it is possible to prevent deterioration in the grinding state. Therefore, it is possible to continue grinding the workpiece W with high precision.

Furthermore, when symptom management processing is being performed, the dressing operation of the grinding wheel T can be performed when it is determined that a symptom of a deterioration in the grinding condition has occurred, rather than when the number of times the workpiece W has been ground reaches a specified number. Therefore, even if the number of times the workpiece W has been ground exceeds the specified number, grinding can be continued without performing the dressing operation of the grinding wheel T. This makes it possible to lengthen the interval between dressing operations of the grinding wheel T (the number of grinding operations between the previous dressing operation and the next dressing operation). This therefore makes it possible to extend the life of the grinding wheel T.

However, the symptom management process by the control device 30 requires that it acquire the evaluation signal S from the machining state evaluation device 4. The control device 30 may be unable to acquire the evaluation signal S unintentionally, for example, if the power supply to the machining state evaluation device 4 is cut off (power outage) or communication is interrupted. In this way, when the control device 30 is unable to acquire the evaluation signal S from the machining state evaluation device 4, the control device 30 performs a count management process. The count management process is a process that causes the grinding machine body to perform a dressing operation on the grinding wheel T when the number of grinding operations reaches a specified number.

In other words, in situations where symptom management processing cannot be performed, the control device 30 can maintain the condition of the grinding wheel T in good condition by performing count management processing. As a result, deterioration in the grinding accuracy of the workpiece W can be suppressed.

In addition, in this embodiment, the processing state evaluation device 4 is configured to perform evaluation processing for multiple evaluation items related to the processing state ("Evaluation Item 1" to "Evaluation Item 4"). The control device 30 uses the evaluation item setting unit 42 to set the evaluation items to be acquired from the processing state evaluation device 4 from among the multiple evaluation items.

When the control device 30 can acquire an evaluation signal S relating to the evaluation results of the set evaluation items from the processing state evaluation device 4, it performs symptom management processing based on the evaluation results of the evaluation signal S acquired from the processing state evaluation device 4. On the other hand, when the control device 30 cannot acquire an evaluation signal S relating to the evaluation results of the set evaluation items from the processing state evaluation device 4, it performs count management processing.

When the machining state evaluation device 4 is capable of performing evaluation processing for multiple evaluation items, the control device 30 can selectively perform symptom management processing and count management processing as described above, thereby preventing deterioration in the grinding accuracy of the workpiece W.

In this case, if the evaluation item setting unit 42 has been set to not require acquisition for all evaluation items, the control device 30 will not acquire the evaluation signal S from the machining state evaluation device 4. Therefore, the control device 30 performs the count management process.

Furthermore, as shown in Figure 3, the symptom management command R1 is set to four levels of commands R11 to R14. The command content is then implemented according to commands R11 to R14. In particular, when the evaluation result is "defective" or "failure," the command content of the second command R12 and the fourth command R14 is implemented, thereby preventing defects from being generated in the workpiece W.

(Embodiment 2)
The processing by the machining state evaluation device 4 in the grinding system 1 of the second embodiment will be described with reference to Fig. 4. The machining state evaluation device 4 of the first embodiment performs evaluation processing for target evaluation items on all workpieces W. The machining state evaluation device 4 of the present embodiment changes the timing of performing the evaluation processing depending on the degree of success of the evaluation result.

As shown in FIG. 4, after the workpiece W has been ground, the machining state evaluation device 4 performs an evaluation process for the evaluation items on the workpiece W (S1). Next, the machining state evaluation device 4 determines whether the evaluation result is "good" (S2).

Next, if the evaluation result is "good" (S3: Yes), the processing state evaluation device 4 determines whether the degree of goodness is high. For example, if a numerical value is obtained through the evaluation process and the numerical value is between the lower and upper limits representing "good," the evaluation result is evaluated as "good." In this case, if the numerical value is close to the median, the degree of goodness is considered to be "high," and if the numerical value is close to the lower or upper limit, the degree of goodness is considered to be "low."

If the degree of satisfactory is "high" (S4: Yes), the timing of the evaluation process is set to the first set number of times Na (S5). Next, the number of grinding processes N since the previous evaluation process is obtained (S6). Then, it is determined whether the number of grinding processes N has reached the first set number of times Na (S7). If the number of grinding processes N has not reached the first set number of times Na (S7: No), the process of S6 is performed and the process is repeated.

In S7, if the number of grinding processes N reaches the first set number of times Na (S7: Yes), the process returns. That is, evaluation processing is performed on the workpiece W (S1). Therefore, if the degree of quality is determined to be "high," the evaluation processing interval becomes the first set number of times Na.

If the degree of goodness is "low" in S4 (S4: No), the timing of the evaluation process is set to a second set number of times Nb (S8). The second set number of times Nb is set to a number that is less than the first set number of times Na. Next, the number of grinding processes N since the previous evaluation process is obtained (S9). Then, it is determined whether the number of grinding processes N has reached the second set number of times Nb (S10). If the number of grinding processes N has not reached the second set number of times Nb (S10: No), the process of S9 is performed and the process is repeated.

In S10, if the number of grinding operations N reaches the second set number of operations Nb (S10: Yes), the process returns. That is, evaluation processing is performed on the workpiece W (S1). Therefore, if the degree of quality is determined to be "low," the evaluation processing interval becomes the second set number of operations Nb.

In this way, when the evaluation result is good and the degree of goodness is high, the machining state evaluation device 4 sets a higher number of grinding operations for the workpiece from the previous evaluation process until the next evaluation process, compared to when the degree of goodness is low. In cases where the machining state evaluation device 4 performs evaluation processing after the grinding cycle of the workpiece W is completed, performing evaluation processing on all workpieces W may result in a long cycle time. In such cases, this embodiment is effective. Furthermore, because it is possible to reduce the calculation load on the machining state evaluation device 4, it is highly useful for performing other processes, etc.

(Embodiment 3)
The grinding system 1 of the third embodiment will be described with reference to Fig. 5. The grinding system 1 of the present embodiment differs from the grinding system 1 of the first embodiment only in the PLC 31 of the control device 30.

Note that, unless otherwise specified, the symbols used in embodiment 3 and subsequent embodiments that are the same as those used in the previous embodiments represent the same components, etc., as in the previous embodiments.

The PLC 31 of this embodiment includes a signal acquisition unit 41, an evaluation item setting unit 42, an evaluation signal acquisition determination unit 44, and an output unit 45. The PLC 31 of this embodiment does not include the evaluation item validity determination unit 43 that constitutes the PLC 31 of embodiment 1. The other components 41, 42, 44, and 45 are the same as those of embodiment 1. The grinding system 1 of embodiment 3 achieves the same effects as the grinding system 1 of embodiment 1, except for the part related to the evaluation item validity determination unit 43 of embodiment 1.

(Embodiment 4)
The grinding system 1 of the fourth embodiment will be described with reference to Figures 6 and 7. The grinding system 1 of the present embodiment differs from the grinding system 1 of the first embodiment in the PLC 31 of the control device 30.

The PLC 31 includes a signal acquisition unit 51, an evaluation result determination unit 52, and an output unit 53. The PLC 31 does not include the evaluation item setting unit 42 that constitutes the PLC 31 of embodiment 1. Therefore, the signal acquisition unit 51 acquires evaluation signals S for all evaluation items from the machining state evaluation device 4. However, the signal acquisition unit 51 does not acquire the evaluation result "good," but instead acquires other evaluation results such as "bad," "warning," and "failure." The machining state evaluation device 4 can be configured not to output an evaluation signal S for the evaluation result "good," and the signal acquisition unit 51 can also be configured not to acquire an evaluation signal S for the evaluation result "good."

The evaluation result determination unit 52 determines whether an evaluation result other than "good" such as "poor," "warning," or "failure" has been obtained based on the evaluation signal S acquired by the signal acquisition unit 51. If the evaluation result determination unit 52 acquires an evaluation result of "poor," "warning," or "failure," it determines "Yes," and if no evaluation result has been acquired, it determines "No."

The output unit 53 includes a symptom management processing unit 53a and a count management processing unit 53b. When the evaluation result determination unit 52 obtains an evaluation result of "bad,""warning," or "failure," the symptom management processing unit 53a executes symptom management processing in the output unit 53. The symptom management processing unit 53a executes symptom management processing to output a symptom management command R3 to the CNC device 32.
On the other hand, if the evaluation result determination unit 52 does not obtain any evaluation results, the output unit 53 performs a count management process using the count management processing unit 53b. The count management process is the same as the count management process in the first embodiment.

The symptom management command R3 will be described with reference to Figure 7. The symptom management command R3 includes a first command R31, a second command R32, and a third command R33. The first command R31, the second command R32, and the third command R33 are similar to the second command R12, the third command R13, and the fourth command R14 in embodiment 1. This embodiment also achieves the same effects as embodiment 1.

REFERENCE SIGNS LIST 1 Grinding system 4 Machining state evaluation device 10 Grinding machine body 30 Control device T Grinding wheel W Workpiece S Evaluation signal

Claims (8)

a grinding machine body that performs grinding on a workpiece using a grinding wheel;
an observation device provided on the grinding machine body for detecting measurement data observed during grinding in order to observe a processing state of the workpiece during grinding by the grinding machine body;
a control device that counts the number of grinding processes that indicates the number of times the grinding process has been performed by the grinding machine body and controls the operation of the grinding machine body;
a machining state evaluation device that performs evaluation processing for evaluation items related to the machining state when the grinding machine main body grinds the workpiece based on the measurement data detected by the observation device , and outputs evaluation signals related to the evaluation results of the evaluation items to the control device;
Equipped with
the machining state evaluation device is set to perform the evaluation process for each grinding cycle,
The control device
When the evaluation signal can be acquired from the processing state evaluation device, if the evaluation result of the evaluation signal acquired from the processing state evaluation device indicates that a sign of deterioration in the grinding processing state by the grinding wheel has occurred, a sign management process is performed to cause the grinding machine main body to perform a correction process for the grinding wheel;
a grinding system that, when the evaluation signal cannot be acquired from the processing state evaluation device despite being set to acquire the evaluation signal from the processing state evaluation device, performs a number management process that causes the grinding machine main body to perform the correction process on the grinding wheel when the number of grinding processes reaches a specified number. The grinding system of claim 1, wherein the correction process is a dressing operation that sharpens the grinding wheel. the machining state evaluation device is configured to perform the evaluation process for a plurality of evaluation items related to the machining state,
The control device
The evaluation items to be acquired from the processing state evaluation device are set among the plurality of evaluation items,
When the evaluation signal relating to the evaluation result of the set evaluation item can be acquired from the processing state evaluation device, the symptom management process is performed based on the evaluation result of the evaluation signal acquired from the processing state evaluation device;
3. The grinding system according to claim 1, wherein the number management process is performed when the evaluation signal relating to the evaluation result of the set evaluation item cannot be obtained from the machining state evaluation device. The grinding system of claim 3, wherein the control device further performs the count management process when all of the evaluation items are set to not require acquisition. The symptom management process includes:
If the evaluation result is good, the correction process is not performed;
If the evaluation result indicates that a sign of deterioration in the grinding state by the grinding wheel has occurred, the correction process is carried out;
A grinding system according to any one of claims 1 to 4, wherein grinding of the workpiece by the grinding machine body is stopped when the evaluation result is poor or when the evaluation result fails the evaluation process. The grinding system described in any one of claims 1 to 5, wherein the control device performs the correction process when the symptom management process is performed and the number of grinding operations exceeds the specified number, and the control device is unable to obtain the evaluation signal from the machining state evaluation device. The grinding system according to any one of claims 1 to 6, wherein the processing state evaluation device performs the evaluation process for at least one of the evaluation items: the presence or absence of chatter that occurs during grinding, the magnitude of the chatter, the presence or absence of grinding burns that occur on the workpiece during grinding, the surface roughness of the ground surface of the workpiece, and the shape of the workpiece due to grinding. 8. The grinding system according to claim 1 , wherein the control device further instructs an external device to perform the number of times management process when the number of times management process is to be performed.