WO2023105633A1

WO2023105633A1 - Dressing method and dressing device for grinding wheel

Info

Publication number: WO2023105633A1
Application number: PCT/JP2021/044953
Authority: WO
Inventors: 新樹伊藤; 聡太小林; 和寛佐藤; 剛正北野; 肇伊藤
Original assignee: 黒田精工株式会社
Priority date: 2021-12-07
Filing date: 2021-12-07
Publication date: 2023-06-15
Also published as: CN117062690A; TW202322976A

Abstract

[Problem] To appropriately perform setting of a dressing timing that has repeatability, effectively using experience and knowledge of a skilled expert regarding dressing timings for grinding wheels. [Solution] The problem is addressed by: monitoring a grinding load during execution of grinding using a grinding wheel 24 under predetermined grinding conditions; saving the load at a point in time of a dressing set button 60, which is operated by an operator, generating a trigger signal as a dressing threshold value in a storage medium 62 along with the grinding conditions; reading the dressing threshold value corresponding to the grinding conditions from the storage medium 62 at the next time of execution of grinding; and executing dressing of the grinding wheel using this dressing threshold value.

Description

Grinding wheel dressing method and dressing device

The present invention relates to a method and device for dressing a grinding wheel in a grinding device.

As a device for detecting the dressing time of the grinding wheel in the grinding machine, the standard power consumption of the electric motor that drives the grinding wheel is compared with the power consumption during grinding. It is known that it is time to dress (for example, Patent Document 1).

JP-A-3-251366

The dressing of the grinding wheel should be done just enough to maintain proper grinding and to control the wear of the grinding wheel. However, in view of this fact, an algorithm for setting the dressing timing according to the grinding conditions has not been established. In addition, the experience and knowledge of experts are not effectively used to set reproducible dressing times.

In view of the above background, it is an object of the present invention to appropriately set a reproducible dressing time by effectively utilizing the experience and knowledge of experts regarding the dressing time of a grinding wheel.

One aspect of the present invention for solving the above-mentioned problems is a grinding wheel dressing method, wherein the grinding load is monitored and operated by an operator while grinding is performed under predetermined grinding conditions using the grinding wheel. storing the load at the time when the trigger signal generating device generates the trigger signal as a dressing threshold in a storage medium together with the grinding conditions, and reading out the dressing threshold corresponding to the grinding conditions from the storage medium when performing the next grinding; The dressing threshold is used to dress the grinding wheel.

According to this aspect, the reproducible dressing timing is set by effectively utilizing the operator's experience and knowledge regarding the dressing timing of the grinding wheel, and the grinding wheel is appropriately dressed with good reproducibility.

In order to solve the above problems, one aspect of the present invention is to monitor the grinding load under predetermined grinding conditions using a grinding wheel, and dress the grinding wheel to be prescribed according to the grinding conditions. A dressing method for storing in a storage medium a dressing threshold indicating the arrival of time, and performing dressing of the grinding wheel using the dressing threshold stored in the storage medium, the dressing method corresponding to the grinding conditions of a workpiece to be ground. If the dress threshold value to be used does not already exist in the storage medium, the load at the time when the trigger signal generation device operated by the operator generates the trigger signal under the execution of grinding under predetermined grinding conditions using the grinding wheel is newly updated. and stored in the storage medium together with the grinding conditions as a dress threshold value.

According to this aspect, the setting of the dressing timing with reproducibility is appropriately performed by effectively utilizing the operator's experience and knowledge regarding the dressing timing of the grinding wheel, and the dressing of the grinding wheel is appropriately performed with good reproducibility. will be

In the above aspect, preferably, the grinding load includes the power value of the electric motor that rotationally drives the grinding wheel or the rotational speed of the grinding wheel.

According to this aspect, the grinding load can be monitored with high accuracy and excellent responsiveness.

In the above aspect, preferably, the grinding conditions include the type of the grinding wheel, the material of the workpiece to be ground, the presence or absence of heat treatment of the workpiece, the rotation speed of the grinding wheel, the depth of cut for grinding, and the feed speed of the workpiece. including.

In the above aspect, the storage medium preferably stores the dressing condition including the dressing amount and the rotational speed of the grinding wheel during dressing, together with the dressing threshold.

One aspect of the present invention for solving the above-mentioned problems is a grinding wheel dressing device comprising: a load monitoring device for monitoring the grinding load of the grinding wheel; A storage medium for storing the load indicating the arrival of time as a dressing threshold along with the grinding conditions, a trigger signal generating device operated by an operator to generate a trigger signal, and a grinding condition for a workpiece to be ground is stored in the storage medium. If pre-existing in the medium, dressing of the grinding wheel is performed when the load in grinding the workpiece reaches the corresponding dressing threshold, and for the workpiece to be ground, the grinding conditions are stored in the storage. and a dressing control device for storing the load at the time when the trigger signal generating device generates the trigger signal as the dressing threshold in the storage medium together with the grinding conditions, if not existing in the medium.

According to the above aspect, reproducible setting of the dressing timing is appropriately performed by effectively utilizing the experience and knowledge of the skilled person regarding the dressing timing of the grinding wheel.

1 is a perspective view showing an embodiment of a grinding apparatus suitable for implementing the grinding wheel dressing method and the grinding dressing method according to the present invention; FIG. Block diagram showing the control system of the grinding machine Flowchart showing a control flow according to one embodiment of the same grinding apparatus Flowchart showing a control flow according to another embodiment of the same grinding machine

　Hereinafter, an embodiment of a dressing method and a dressing apparatus for a grinding apparatus according to the present invention will be described with reference to the drawings.

First, referring to FIG. 1, a suitable grinding apparatus 10 for implementing the dressing method according to the present invention will be described. The grinding device 10 is a surface grinding machine, and includes a bed (base) 11 fixedly arranged on the floor and a Y-axis table provided on the bed 11 so as to be movable in the Y-axis direction (back and forth direction). 12 and an X-axis table 14 provided on a Y-axis table 12 so as to be movable in the X-axis direction (horizontal direction).

A dresser 16 for dressing a grinding wheel 24, which will be described later, is attached to the end of the X-axis table 14 in the left-right direction.

As will be described later, in the grinding apparatus 10, a threshold for determining the timing of dressing the grinding wheel 24 (hereinafter referred to as a dressing threshold) is set with respect to the index indicating the grinding load. is executed. Such a grinding load index is not particularly limited, but in the present embodiment, as an example of the grinding load index, the power value or the spindle rotation speed of the spindle motor 32 (see FIG. 2) is used. explain.

The grinding apparatus 10 includes a column 18 integrated with the bed 11, a spindle head 20 provided on the column 18 so as to be movable in the Z-axis direction (vertical direction), a spindle 22 provided on the spindle head 20, A disk-shaped grinding wheel 24 is replaceably attached to the spindle 22 . The spindle head 20 is provided with a spindle motor (electric motor) 32 such as an induction motor for rotating the grinding wheel 24 .

Movement of the Y-axis table 12, the X-axis table 14, and the spindle head 20 in each axial direction is performed by a feed screw device (not shown) for each axis.

Next, the drive system and control system of the grinding device 10 will be described with reference to FIG. The grinding machine 10 has a Y-axis motor 26, an X-axis motor 28 and a Z-axis motor 30 that drive the feed screw devices of each axis.

A control device 40 that controls the grinding device 10 has a computerized numerical controller (CNC) 42 , a spindle inverter 44 and a programmable logic controller (PLC) 46 .

The CNC 42 includes an electronically controlled processor that executes NC programs, and controls the Y-axis motor 26, X-axis motor 28 and Z-axis motor 30. Thus, movement of the Y-axis table 12 in the Y-axis direction, movement of the X-axis table 14 in the X-axis direction, and movement of the spindle head 20 in the Z-axis direction are controlled. As a result, the workpiece W on the X-axis table 14 is ground while the grinding wheel 24 is rotated by the spindle motor 32 .

The spindle inverter 44 receives a voltage command from a spindle speed setting unit 50 including a volume knob 51 (see FIG. 1) provided in the cabinet 41 of the control device 40, and adjusts the drive power for the spindle 22 based on the voltage command. Control. Thereby, the rotation speed of the spindle 22, in other words, the rotation speed of the grinding wheel 24 is controlled.

The PLC 46 has a PLC body 47 including a processor that executes a ladder program, an internal register 52 including rewritable storage elements for various parameters related to grinding and dressing, and a recipe storage function section 53 .

The PLC 46 includes a Y-axis speed select switch 54 provided in the cabinet 41, an input unit 56 such as a touch panel, a display unit 58 such as a liquid crystal panel, a dress set button (trigger signal generator) 60, a flash memory (SD card), and the like. A storage device (storage medium) 62 is connected. The PLC 46 is bus-connected to the CNC 42 and communicatively connected to the spindle inverter 44 .

The dress set button 60 is operated by the operator at any time during the grinding of the work W by the grinding wheel 24, that is, while the work W is being ground, and this operation generates a trigger signal indicating that the dressing time has come. and outputs the trigger signal to the control device 40 .

The control device 40 includes, as a monitoring device for monitoring the grinding load, a power detection unit 45 that detects the power value (voltage value) of the spindle motor 32, and a rotation speed of the spindle motor 32 (rotation speed of the grinding wheel 24). A spindle rotation speed detector 34 is connected. The PLC 46 inputs the power value of the spindle motor 32 detected by the power detector 45 and the spindle rotation speed detected by the spindle rotation speed detector 34 . The power value of the spindle motor 32 increases as the grinding load increases. The rotation speed of the spindle motor 32 decreases as the grinding load increases. In practice, either the spindle rotation speed detection unit 34 or the power detection unit 45 may be provided.

The input unit 56 is operated by the operator and used to input the grinding range of the workpiece W, the grinding conditions, the dressing conditions of the grinding wheel 24, and the dressing threshold value (default value). Each of these input items is transferred from the input section 56 to the internal register 52 of the PLC 46 and stored in the internal register 52 .

The grinding range of the workpiece W is determined by the coordinate values of the grinding device 10 in the Y-axis direction and the X-axis direction. Grinding conditions for the workpiece W include the type of grinding wheel 24, the material of the workpiece W, the presence or absence of heat treatment of the workpiece W, the total removal amount, the amount of grinding cut, the amount of finish cut, the number of spark-outs, the X-axis feed rate, the left and right Feed speed, cross feed speed, machining range, spindle speed, etc. The X-axis feed speed, the lateral feed speed, and the longitudinal feed speed belong to the work W feed speed. The spindle speed belongs to the speed of the grinding wheel 24 .

Dressing conditions for the grinding wheel 24 include a threshold for dressing depending on the electric power value of the spindle motor 32 or the rotation speed of the grinding wheel 24 (spindle rotation speed), the amount of dressing cut, the rotation speed of the grinding wheel 24 (spindle rotation speed), and the forward/backward feed. speed, etc.

The dressing threshold is an index that indicates the advent of the time to dress the grinding wheel 24 . The dressing threshold is set for each grinding condition and stored in the storage device 62 as a recipe paired with the grinding condition for each grinding condition. A collection of recipes for each grinding condition stored in the storage device 62 is called a database 63 . Dressing thresholds include those based on the power value of the main shaft motor 32 and those based on the rotation speed of the main shaft motor 32 .

The PLC 46 reads out the dressing threshold from the storage device 62 together with the grinding conditions, if the dressing threshold exists as one recipe in the storage device 62 together with the grinding conditions of the workpiece W to be ground. The PLC 46 monitors the power value or rotation speed of the spindle motor 32 while grinding the workpiece W, and determines that it is time to dress the grinding wheel 24 when the power value or rotation speed reaches the read-out dressing threshold value. A command to dress the grinding wheel 24 is output to the CNC 42 and the spindle inverter 44 .

By this command, dressing of the grinding wheel 24 is executed by the dresser 16 according to the dressing conditions specified in the corresponding recipe.

The PLC 46 monitors the generation of a trigger signal based on the operation of the dress set button 60 when the storage device 62 does not have a dress threshold corresponding to the grinding conditions of the workpiece W to be ground.

The dress set button 60 is operated by the operator at any time during the grinding of the workpiece W. The operator operates the dress set button 60 when it is determined that it is time to dress the grinding wheel 24 based on observation of the actual grinding conditions such as the degree of occurrence of sound, vibration and sparks during the grinding operation of the workpiece W. do. A trigger signal is generated by operating the dress set button 60 .

When the trigger signal is generated by operating the dress set button 60, the PLC 46 sets the power value or rotation speed of the spindle motor 32 at the time of generation of the trigger signal in the internal register 52 as the dress threshold. After the grinding of one workpiece W is completed, the PLC 46 stores the dressing threshold written in the internal register 52 as one recipe in the database 63 of the storage device 62 together with the grinding conditions of the workpiece W by the recipe storage function unit 53. Write.

If the operator who operates the dress set button 60 is an expert, the asset (skill) related to determining the arrival of the dressing time based on the experience and knowledge of the expert will be used to set the dress threshold.

Next, if the dressing conditions including the dressing threshold of the workpiece W to be ground exist in the database 63 as one recipe together with the grinding conditions, the PLC 46 performs the dressing including the grinding conditions and the dressing threshold described in the recipe. Transfer the condition to internal register 52 . Then, the control device 40 automatically grinds the workpiece W and dresses the grinding wheel 24 based on the grinding conditions and dressing conditions including the dressing threshold described in the recipe transferred to the internal register 52 .

As a result, once the dressing threshold is set, the grinding wheel 24 can be appropriately dressed while effectively utilizing the dressing assets of the skilled operator, even if the skilled operator is absent.

Next, one control flow of the grinding apparatus 10 executed by the control device 40 will be described with reference to the flowchart shown in FIG.

First, the database 63 of the storage device 62 is searched for a recipe for the workpiece W to be ground next as a registered recipe (step S10). If there is no registered recipe (No at step S10), the database 63 is searched for a registered recipe containing at least one condition close to the grinding condition of the workpiece W to be ground next (step S11). These searches may be performed by an operator.

If there is no registered recipe containing conditions close to the grinding conditions of the workpiece W to be ground next in the database 63 (No at step S11), manual grinding of the workpiece W is started by the operator's operation (step S12). Manual grinding is performed while the operator adjusts the grinding conditions. Further, the operator determines that it is time to dress while adjusting the dressing conditions while observing the degree of generation of sound, vibration and spark during manual grinding of the workpiece W.

Under this judgment, when the operator operates the dress set button 60 to set the dress threshold (step S13), the dress threshold is set by the PLC 46 (step S14).

After this, the control device 40 starts automatic grinding under the adjusted grinding conditions. Then, the control device 40 monitors whether the power value of the spindle motor 32 detected by the power detector 45 or the spindle rotation speed detected by the spindle rotation speed detector 34 reaches the dress threshold. When the power value of the spindle motor 32 or the spindle rotation speed reaches the dressing threshold value, the control device 40 executes dressing (automatic dressing) of the grinding wheel 24 according to the adjusted dressing conditions (step S15).

Automatic grinding and automatic dressing are performed until the grinding of one workpiece W is completed (step S16). When the machining of one workpiece W is completed, the PLC 40 registers the grinding conditions and dressing threshold values of the grinding process that has been performed so far as one recipe in the database 63 of the storage device 62 (step S17).

If there is a registered recipe containing conditions close to the grinding conditions of the workpiece W to be ground next in the database 63 (Yes at step S11), the recipe is read from the storage device 62 by the operator's operation, and the grinding conditions of the recipe are set. It is set in the control device 40 (step S18).

After this, manual grinding of the workpiece W is started by the operator's operation (step S19). Manual grinding is performed while the operator adjusts grinding conditions other than the grinding conditions from the recipe. Further, the operator determines that it is time to dress while adjusting the dressing conditions while observing the degree of generation of sound, vibration and spark during manual grinding of the workpiece W.

Under this judgment, when the operator operates the dress set button 60 to set the dress threshold (step S20), the dress threshold is set by the PLC 46 (step S21).

After this, the control device 40 executes steps S15 to S17 described above.

If there is a registered recipe (Yes at step S10), the recipe is read from the database 63 of the storage device 62 into the PLC 52 under the operator's operation (step S22). When the reading is completed, automatic control by the control device 40 performs automatic grinding according to the grinding conditions of the recipe and automatic dressing according to the dressing threshold and dressing conditions of the recipe until the machining of one workpiece W is completed (step S23, step S24)

Next, another control flow of the grinding device 10 will be described with reference to the flowchart shown in FIG. A control routine indicated by this control flow is executed by the control device 40 .

First, the grinding conditions (recipes) stored in the database 63 of the storage device 62 are searched (step S30), and it is determined whether or not the grinding conditions for the next grinding are in the database 63 (step S31). This determination may include fuzzy search and similarity search in addition to perfect match.

If there are no grinding conditions (No at step S31), the operator or communication, etc. newly sets the grinding conditions to create a new recipe (step S32), and the workpiece W is ground according to the grinding conditions according to the new recipe (step S36).

If there is a grinding condition (recipe) (Yes at step S31), then it is determined whether or not the recipe has a dressing threshold value (step S34). If there is no dressing threshold (No at step S34), the workpiece W is ground under the grinding conditions described in the corresponding recipe (step S36). Also in this embodiment, the dress threshold value may be based on the power value of the spindle motor 32 or the number of rotations of the spindle.

If there is a dress threshold (Yes at step S34), the dress threshold is read from the database 63 and set in the control device 40 (step S35). After that, the workpiece W is ground according to the grinding conditions described in the corresponding recipe (step S36).

Next, it is determined whether or not the recipe being used has a dress threshold (step S37). If there is no dressing threshold value (No at step S37), it is determined whether or not it is time to set a new dressing threshold value while the workpiece W is being ground (step S38). This determination is triggered by the operation of the dress set button 60 by the operator. When there is no trigger input (No at step S38), the end of grinding of the workpiece W is monitored (step S39).

When there is a trigger input (Yes at step S38), the power value or rotation speed of the spindle motor 32 at the time of trigger input is set as a dressing threshold value and stored in the database 63, that is, written to the corresponding recipe (step S40). At the same time, the grinding is stopped and the grinding wheel 24 is dressed (step S42).

If the recipe being used has a dress threshold value (Yes at step S37), it is determined whether or not the power value or rotation speed of the spindle motor 32 is at the dress threshold value (step S41). When the power value or rotation speed of the spindle motor 32 reaches the dressing threshold value, the grinding is stopped and the grinding wheel 24 is dressed (step S42).

When the dressing of the grinding wheel 24 is completed, the end of grinding of the workpiece W is monitored (step S43).

As a result, the dressing of the grinding wheel 24 is automated.

Although the specific embodiments have been described above, the present invention is not limited to the above embodiments and modifications, and can be widely modified. For example, the control device 40 is not limited to those including the CNC 42 and PLC 46, and may include a microcomputer. The grinding apparatus 10 may be one in which the Y-axis table 12 is omitted and the column 18 moves in the Y-axis direction with respect to the bed 11 . The grinding wheel 24 may be dressed not by the dresser 16 provided on the X-axis table 14 but by a rotary dressing method. The spindle motor 32 may be controlled by a motor or a motor drive circuit other than an inverter-controlled induction motor. Axial feed of the Y-axis table 12 and the X-axis table 14 may be hydraulically driven. The Y-axis speed select switch 54, the dress set button 60 and the like may be provided on the bed 11 and the like. The grinding wheel dressing method and dressing apparatus according to the present invention can also be applied to various machine tools other than surface grinders.

10: grinding device 11: bed 12: Y-axis table 14: X-axis table 16: dresser 18: column 20: spindle head 22: spindle 24: grinding wheel 26: Y-axis motor 28: X-axis motor 30: Z-axis motor 32 : Spindle motor (electric motor)
34: Spindle rotation speed detector 40: Control device 41: Cabinet 42: Computer numerical control processor (CNC)
44: Main shaft inverter 45: Power detection unit (power monitoring device)
46: programmable logic controller (PLC)
47 : PLC main unit 50 : Spindle speed setting unit 51 : Volume knob 52 : Internal register 53 : Recipe storage function unit 54 : Y-axis speed select switch 56 : Input unit 58 : Display unit 60 : Dress set button (trigger signal generation Device)
62: storage device (storage medium)
63: database W: work

Claims

A method of dressing a grinding wheel, comprising:
Grinding load is monitored under predetermined grinding conditions using the grinding wheel, and the load at the time when a trigger signal generator operated by an operator generates a trigger signal is stored as a dress threshold together with the grinding conditions. save to media,
A method of dressing a grinding wheel, wherein the dressing threshold value corresponding to the grinding condition is read from the storage medium and the grinding wheel is dressed using the dressing threshold value when the next grinding is executed.
monitoring the grinding load under predetermined grinding conditions using a grinding wheel, and storing in a storage medium a dressing threshold indicating arrival of a dressing time for the grinding wheel to be defined according to the grinding conditions; A dressing method for performing dressing of the grinding wheel using a dressing threshold stored in the storage medium, comprising:
If the dress threshold corresponding to the grinding conditions of the workpiece to be ground does not already exist in the storage medium, a trigger signal generating device operated by an operator is triggered while grinding is being performed using the grinding wheel under predetermined grinding conditions. A method of dressing a grinding wheel in which the load at the time of signal generation is stored in the storage medium together with the grinding conditions as a new dressing threshold.
The grinding wheel dressing method according to claim 1 or 2, wherein the grinding load includes a power value of an electric motor that rotationally drives the grinding wheel or a rotational speed of the grinding wheel.
4. The method according to any one of claims 1 to 3, wherein the grinding conditions include the type of the grinding wheel, the material of the work to be ground, the presence or absence of heat treatment of the work, the number of revolutions of the grinding wheel, the amount of grinding cut, and the feed speed of the work. A method of dressing a grinding wheel according to any one of the preceding paragraphs.
The grinding wheel dressing method according to any one of claims 1 to 3, wherein the storage medium stores the dressing condition including the dressing amount and the rotation speed of the grinding wheel during dressing, along with the dressing threshold.
a load monitoring device for monitoring the grinding load by the grinding wheel;
a storage medium for storing, together with the grinding conditions, the load indicating the arrival of the dressing time of the grinding wheel, which is to be defined according to the grinding conditions, as a dressing threshold value;
a trigger signal generating device operated by an operator to generate a trigger signal;
for a workpiece to be ground, if the grinding conditions are already in the storage medium, dressing the grinding wheel when the load in grinding the workpiece reaches the corresponding dressing threshold; For a work to be ground, if the grinding conditions for the workpiece do not already exist in the storage medium, the load at the time when the trigger signal generating device generates the trigger signal is stored in the storage medium together with the grinding conditions as the dressing threshold. A grinding wheel dressing device having a dressing control device for
The grinding wheel dressing device according to claim 6, wherein the grinding load includes the power value of the electric motor that rotationally drives the grinding wheel or the rotational speed of the grinding wheel.