JP2937449B2 - Method and apparatus for correcting grinding feed start position of grinding machine - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to a method and a device for correcting a grinding feed start position of a grinding machine.

[Conventional technology]

Generally, in a grinding machine, as shown in FIGS. 5 (A) and (B), the grinding wheel 1 is rapidly moved in the axial direction with respect to the workpiece W from an intermediate stop position 0 to a predetermined grinding feed start position a. , The grinding wheel 1 is advanced in the axial direction at a predetermined grinding feed speed from the grinding feed start position a, and is brought into contact with the workpiece W. After the contact, the grinding wheel 1 is moved along a trajectory indicated by a chain line in the drawing. The workpiece W is also moved in a direction perpendicular to the axial direction to grind the workpiece W. When the grinding of the workpiece W is completed, the grindstone 1 is returned to the intermediate stop position, and the workpiece W, which has been completely ground by the loading device (not shown), is carried out of the grinding machine. After that, the above operation is repeated, whereby a large number of workpieces W are continuously ground.

[Problems to be solved by the invention]

When grinding a large number of workpieces W with the above-mentioned grinding machine, the stock removal of the workpiece W changes stepwise between lots, or the size of the grindstone 1 changes stepwise due to wear of the dress diamond nib. Therefore, it is necessary to set the grinding feed start position a in consideration of the stepwise change.

If the grinding feed start position a is set near the workpiece W without anticipating the stepwise change of the machining allowance in the grinding machine, if the machining allowance of the workpiece W increases, the grinding wheel 1 may be used.
Collides with the workpiece W during the rapid approach, an alarm of excessive machining is issued, and the grinding machine stops.

Therefore, conventionally, in order to prevent the above-described collision, a grinding feed start position a is set in consideration of a step change such as a stock removal,
As shown in FIG. 5 (A), even when the machining allowance of the workpiece W increases, the grinding feed start position a and the machining end face of the workpiece W are increased.
At least the required minimum gap q between the Wa (= q ₀₎
Was provided.

However, as described above, when the machining allowance of the workpiece W is reduced as shown in FIG. 5B, the distance between the grinding feed start position a and the machining end face Wa of the workpiece W is reduced. The gap q (= q ₁ > q ₀ ) becomes unnecessarily large, and the difference between q ₁ and q ₀ and the idle grinding time increase, leading to a decrease in machining efficiency.

In view of the above circumstances, an object of the present invention is to provide a method and an apparatus for correcting a grinding feed start position of a grinding machine, which can improve machining efficiency while preventing a grinding stone from colliding with a workpiece during rapid approach. It is assumed that.

[Means for solving the problem]

The method for correcting the grinding feed start position of the grinding machine according to the present invention is such that after the grindstone rapidly approaches the workpiece to the grinding feed start position set in the grinding feed start position setting means,
In a grinding machine configured to advance at a predetermined grinding feed speed from the grinding feed start position and contact the workpiece, a position at which the grinding wheel contacts the workpiece is detected by contact position detecting means, The grinding feed start position is corrected based on a difference between a detected contact position and a gap between the grinding feed start position set in the grinding feed start position setting means and a predetermined target value of the gap. It was made.

Further, after the grindstone is rapidly approached to the workpiece to the grinding feed start position set by the grinding feed start position setting means, it is advanced at a predetermined grinding feed speed from the grinding feed start position to the workpiece. In a grinding machine configured to be brought into contact, a contact position detecting means for detecting a position at which the grindstone comes into contact with the workpiece, and a grinding feed set to the detected contact position and the grinding feed start position setting means. A grinding feed start position correcting means for correcting the grinding feed start position based on a difference between a gap with the start position and a predetermined target value of the gap is provided.

[Action]

According to the above configuration, the contact position is detected by the contact position detecting means, and based on a difference between the gap between the contact position and the set grinding feed start position and a predetermined target value of the gap. The grinding feed start position is corrected. Therefore, even if the stock removal of the workpiece changes stepwise, the grinding feed start position can always be corrected near the workpiece according to the change.

〔Example〕

FIG. 1 shows an embodiment of a grinding feed start position correcting device according to the present invention.

In the figure, A is a grinding machine, which is a grinding wheel 1, a wheel head 11, a grinding wheel drive motor 12, a grinding table 13, and a work support table.
It has 14 and.

The workpiece W to be ground by the grindstone 1 is positioned on the work support table 14, and the work support table 14 is moved in the X-axis direction (a direction orthogonal to the axial direction of the grindstone 1) by a work support table feed motor (not shown). It is configured to be moved.

The grindstone 1 is supported by a wheel head 11 and is configured to be rotationally driven at a constant rotation speed by a grindstone drive motor 12. The grindstone drive motor 12 is configured to be driven when a constant current is supplied from the grindstone drive motor controller 15 and to stop when the current is cut off.

Wheel head 11 and grinding wheel drive motor 12
The grinding table 13 is mounted on the top, and is configured to be moved in the Z-axis direction (the axial direction of the grinding wheel 1) by the cutting feed motor 16. Therefore, the grindstone 1 can be moved closer to or farther from the workpiece W by driving the cutting feed motor 16 to reciprocate the grinding table 13 in the Z-axis direction. Further, by changing the rotation speed of the cutting feed motor 16, the moving speed of the grinding wheel 1 in the Z-axis direction can be changed.

A position detector 17 reads the number of rotations of the cutting feed motor 16 from the home position to the current position of the grindstone 1 to read the current position of the grindstone 1 in the Z-axis direction in real time. It is configured to detect. Note that the origin return of the grinding wheel 1 is confirmed by an origin return confirmation switch (not shown).

Reference numeral 18 denotes a feed motor controller, which feedback-controls the rotation of the feed motor 16 and its stop and rotation speed while comparing a command signal from the machine controller B with a detection signal from the position detector 17. It is configured as follows. More specifically, when grinding the workpiece W, the grindstone 1 rapidly advances toward the workpiece W to the grinding feed start position a set in the grinding feed start position setting means 71 of the machine controller B, and thereafter, Further, the cutting feed motor 16 is controlled so as to advance at a predetermined grinding feed speed from the grinding feed start position a.

2 is a grinding load detector for detecting the output of the grinding wheel drive motor 12 which is correlated with the grinding load. The detection result of this grinding load detector is a gap eliminator (contact detector).
3 is output.

The gap eliminator 3 is configured to detect that the grinding wheel 1 has come into contact with the workpiece W based on the detection result of the grinding load detector 2. In other words, when the grindstone 1 approaches the workpiece W, when the grindstone 1 comes into contact with the workpiece W from the idling state, the grinding load, that is, the output of the grindstone drive motor 12 greatly changes at that moment. To
By detecting the change from the detection result of the grinding load detector 2, it is configured to detect that the grinding wheel 1 has come into contact with the workpiece W. Also, the gap eliminator 3
When it is detected that the grinding wheel 1 has come into contact with the workpiece W, a contact detection signal is output to the main cutting feed control unit 7 of the machine controller B.

The machine controller B includes an initial position input unit 4, a storage unit 5, a detected position input unit 6, and a main cutting feed control unit 7.

The initial position input unit 4 initial position a ₀ of the grinding feed start position a from an initial position setting unit 8 is input, the initial position a ₀
Are stored in the storage unit 5. The initial position a ₀ of the grinding feed start position a is changed by the initial position setting device 8 in accordance with the type of the workpiece W. When the initial position a ₀ is changed by the initial position setting device 8, the storage unit 5 _Is also changed in the same manner. The initial position a
₀ is a position that allows for a large change in the stock removal of the workpiece W due to a change in the lot of the workpiece W or replacement of the grindstone 1 and the diamond nib for the dress, a change in the position of the grindstone 1, and the like, that is, the largest allowance for the workpiece W. even when and if the grinding wheel 1 is shifted to the most workpiece W side, it is set at a position at least minimum gap q ₀ is provided between the machining allowance end surface Wa of the grinding wheel 1 and the workpiece W I have. Incidentally, the gap q ₀ of the minimum required is determined in consideration of the pre-machining tolerance and speed changeover overrun like.

In addition to the initial position a ₀ , the storage unit 5 stores a target value of the gap q from the grinding feed start position a to the machining end surface Wa of the workpiece W. This target value is matched to the minimum gap q _0.

The main cutting feed control unit 7 includes a position detector
The current position of the grinding wheel 1 in the Z-axis direction detected at 17 is input via the detection position input unit 6, a contact detection signal from the gap eliminator 3, and an initial position of the grinding feed start position a from the storage unit 5. a ₀ and target value q _{0 of} gap q
Are respectively input.

The main cutting feed control section 7 has a grinding feed start position setting means 71, a contact position detecting means 72, and a grinding feed start position correcting means 73.

The grinding feed start position setting means 71 determines that the grinding feed start position a
Is set in accordance with various conditions.
That is, the grinding feed start position a, is set to an initial position a ₀ stored first in the storage unit 5 after grinding machine A start, followed there is correction command from the grinding feed start position correcting means 73 when depending on the instruction was set to the position a _1, is configured to set the initial position a ₀ stored in the storage unit 5 when reset by operating the subsequent view outside of the reset switch. The grinding feed start position a set by the grinding feed start position setting means 71 is output to the cutting feed motor controller 18 and the grinding feed start position correcting means 73.

The contact position detecting means 72 reads the current position in the Z-axis direction of the grindstone 1 detected by the position detector 17 when a contact detection signal is input from the gap eliminator 3, so that the grindstone 1 contacts the workpiece W. (Wait edge Wa of workpiece W
The position (b) is detected.

The grinding feed start position correcting means 73 includes a contact position detecting means 72.
After the contact positions b are detected for a predetermined number of workpieces W, the grinding feed start position a is set based on these contact positions b and the grinding feed start position a set in the grinding feed start position setting means 71. The average value q of the gap q from to the contact position b is obtained, the average value q is compared with the target value q ₀ stored in the storage unit 5, and set in the grinding feed start position setting means 71 according to the result. Grinding feed start position a
Is configured to correct.

The machine controller B is configured to control the grindstone drive motor controller 15, the work support base feed motor, the dresser, the loading device, and the like in addition to the control of the cut feed motor controller 18.

2A and 2B show a specific example of the control of the machine controller B.

In the main routine shown in FIG. 2 (A), when started by the grinding machine A startup like, it is first allowed to homing actuator (cut feed motor controller 18 and the workpiece support feeding motor) in step S _1, the grinding wheel 1
To the home position.

Then whether the actuator has all homing confirmed by ON · OFF homing confirmation switch in step S _2,
After confirming that all actuators have returned to the home position,
In Step S ₃ to set the grinding feed start position a at the initial position a _0.

Subsequently, step S ₄ and performs an end face dress and outer diameter dress at step S _5, confirmed by either the loading completion confirmation switch loading is completes at step S _6, confirms that the loading is completed, the step S _{At 7} , the grinding wheel drive motor 12 is driven to rotate the grinding wheel 1 at a constant speed.

Then, after reading the grinding feed start position a at step S _8, the grinding wheel 1 is quickly advanced in the Z-axis direction until the grinding readout feed start position a at step S _9. And
When the grinding wheel 1 at step S ₁₀ to verify that it has advanced to the grinding feed start position a, starts grinding feed in step S _11. That is, the grindstone 1 is advanced quasi-rapidly at the rough grinding speed in the Z-axis direction to the finish grinding start position. As a result, during the quasi-rapid advance, the grinding wheel 1 comes into contact with the surplus end face Wa of the workpiece W, and rough grinding is started.

Step S ₁₁ after execution, after detecting that the grinding wheel 1 is in contact with the workpiece W in step S _12, the in step S ₁₃ 2
A grinding feed start position correction routine shown in FIG.
Incidentally, the grinding wheel 1 at step S ₁₂ it is detected that contact with the workpiece W, by driving the workpiece support feed motor,
The grindstone 1 is advanced relatively to the workpiece W also in the X-axis direction.

Step S ₁₃ After execution, that checks whether the workpiece W to the grinding start position finish at step S ₁₄ is ground (grinding wheel 1 until finish grinding start position is advanced), were ground to fine grinding start position check the grinding wheel 1 is advanced at a grinding speed finish in the Z-axis direction to the grinding completion position finishing in step S _15.

Subsequently, to check the workpiece W to the grinding completion position finishing in step S ₁₆ is ground (finishing grinding wheel 1 to the grinding completion position is advanced), confirms that it is ground to finish grinding completion position, step rapidly retract the grinding wheel 1 to the intermediate stop position S _17, stops the rotation of the grinding wheel 1 at step S _18.

Thereafter, determination to perform the loading into the loading apparatus at step S _19, after exchanging the workpiece W raw and workpiece W which has completed processing, or conditions or not to process continuously at Step S ₂₀ I do. That is, in step S _20, and determines the number of cases and processing completed workpiece W to workpiece W raw is not carried is not continuous processing conditions when it reaches the target number, otherwise in continuous processing conditions It is determined that there is.

Then, when it is determined not to be continuous processing conditions in step S ₂₀ and ends the flowchart is performed repeatedly Step S ₄ thereafter when it is determined that the continuous processing conditions.

In grinding feed start position correction routine shown in FIG. 2 (B), first detects the contact position b in step S _21, followed on the basis of its contact position b and the grinding feed start position a at Step S ₂₂ From grinding feed start position a to contact position b
After calculating the gap q up, it determines conditions or not to correct the grinding feed start position a at step S _23. That is, in step S _23, and determines that the number of detected contact position b corresponding to the processed number of the workpiece W is ground feed start position a modified condition when it reaches the predetermined number n, the contact position b
If the number of times of the detection has not reached the predetermined number n, it is determined that the condition for correcting the grinding feed start position a is not satisfied. And after that,
Each time the number of detections reaches an integer multiple of n (2n, 3n,...), It is determined that the correction condition is satisfied.

If it is determined not to be grinding feed start position a corrected condition in step S _23, step S returns to the main routine
Do ₁₄ On the other hand, when it is determined that the grinding feed start position a corrected condition (YES), calculates the average value q of n gap q value detected until YES this time from the previous YES in step S ₂₄ from , performs the step S _25.

In step S _25, by comparing the gap target value q ₀ stored in the storage unit 5 and the average value q which is the arithmetic average value q and the difference grinding feed start position a response to the target value q ₀ The correction position a 'is obtained. That is, when the average value q is larger than the target value q _{0, a position} closer to the workpiece W from the current grinding feed start position a is calculated as the corrected position a ′. Is smaller than the target value q _{0, a position} closer to the origin position from the current grinding feed start position a by the smaller amount is determined as the corrected position a ′. Therefore, the correction position a 'is a detected contact position (average contact position) position always closer to gap target value q ₀ minutes home position side b. From

Fixed position a grinding feed start position a at step S ₂₅ 'sought after is the obtained correction position a grinding feed start position a at step S _26' is corrected to the average value q in step S ₂₇
From clear, grinding feed start position a at Step S ₂₈
It is determined whether the condition for resetting is satisfied. That is, in step S _28, is determined that the reset condition when the reset signal from the reset switch is outputted, it is determined that otherwise non-reset condition. Note that the reset switch is used when the stock removal of the workpiece W is greatly changed or when the position of the grinding wheel 1 is changed, for example, when the grinding wheel 1 or the diamond nib for dress is replaced, or when the lot of the workpiece W is changed. And outputs a reset signal.

If it is determined not to be reset condition at step S _28, returns to the main routine, if it is determined that the reset condition, modify the grinding feed start position a in the initial position a ₀ in step S ₂₉ Then, the process returns to the main routine.

That is, under the control of the machine controller B, the position b at which the grinding wheel 1 contacts the workpiece W is determined by the contact position detecting means 72.
After performing this for a predetermined number of workpieces W, the grinding feed start position a set in the grinding feed start position setting means 71 is corrected based on the detected contact position b. The method can be performed.

FIG. 3 shows the movement of the grindstone 1 in the Z-axis direction with the elapse of time in the grinding feed start position correcting device.
In the figure, the solid line α indicates the movement from the start of the grinding machine A to the grinding of a predetermined number of workpieces W, and the broken line β indicates the movement after the grinding of a predetermined number.

As shown by the solid line α, after starting the grinding machine A, a grinding feed start position a is maintained until a predetermined number of workpieces W are ground.
There is set to an initial position a _0. Therefore, during the above, for each workpiece W, after the grinding wheel 1 is quickly advanced to its initial position a _0, to advance from its initial position a ₀ at a predetermined grinding feed speed (rough grinding speed) Be moved. That is,
Allowance edge Wa position (contact position) gap from b q '(> q ₀₎ min apart grinding feed of the initial position a ₀ from the grinding wheel 1 of the workpiece W is started. Therefore, until the predetermined number is ground,
It takes an idle grinding time for the gap q '.

On the other hand, during the above, the contact position b
Are respectively detected. Then, when the predetermined number grind the workpiece W, corrected position a grinding feed start position a on the basis of the contact position b as described above detected 'and is determined, grinding feed start position a is the initial position a ₀ from the correction position a' Will be modified to Therefore, as shown by the broken line β, after grinding a predetermined number, the grindstone 1 is rapidly advanced to its correction position a ', and then moved so as to advance at a predetermined grinding feed speed from the correction position a'. Tight, only away gap q ₀ minutes from the contact position b contact position b near the correction position a 'than grinding feed of the grinding wheel 1 is started. Thus, after the predetermined number grinding, air-grinding time is avoid by gaps q ₀ minutes. Therefore, after the predetermined number of grindings, the idle grinding time is reduced by t ₁ hour compared to the time until the predetermined number of grindings.

Next, the movement of the grindstone 1 according to the present invention and the movement of the grindstone 1 according to the conventional method when the stock removal of the workpiece W changes stepwise between lots will be described with reference to FIGS. 4 (A), (B) and FIG. The comparison is made based on FIGS. 5 (A) and (B). Incidentally, FIG. 4 (A) and FIG. 5 (A) shows the case allowance of the workpiece W is maximum, respectively, the initial position a ₀ of the grinding feed start position a is when allowance of the workpiece W is maximum Removal end face Wa position b (=
It is assumed that the gap is set at a position separated by the gap q ₀ from b ₁ ).

In the conventional case shown in FIGS. 5A and 5B, the workpiece W
Maximum even if machining allowance of stepwise changes from lot to lot, since grinding feed start position a is prevented from being modified from an initial position a _0, allowance of the workpiece W as shown in FIG. 5 (B) is If the machining allowance is less than the machining allowance, an empty grinding time for the gap q ₁ (> q ₀ ) is required. That is, allowance of the workpiece W as compared with the case of the maximum, it becomes q ₁ -q ₀ minute extra air grinding time consuming so.

On the other hand, in the case of the present invention shown in FIGS. 4 (A) and 4 (B), every time a predetermined number of workpieces W are ground, the contact position detected during the grinding (the end face Wa of the workpiece W). position) grinding feed start position a on the basis of b is corrected to the position a 'distant ₀ minutes gap q from the machining allowance edge position b. For this reason,
As shown in FIG. 4 (B), when the machining allowance of the workpiece W is smaller than the maximum machining allowance, the grinding feed start position a is shifted toward the workpiece W, that is, the machining end face Wa position of the workpiece W. b
(= B ₂ ) is corrected to the position a ′ (= a ₁ ) separated by the gap q _0, and as a result, even when the machining allowance is reduced, the idle grinding time is the same as the gap q ₀ when the machining allowance is the maximum. It takes only minutes. Therefore, according to the present invention, when the allowance of the workpiece W is smaller than the maximum allowance, the idle grinding time can be reduced by the amount of less than the maximum allowance, as compared with the related art.

Moreover, the machining allowance of the workpiece W changes stepwise from the state shown in FIG. 4 (B), and the machining quantity of the workpiece W increases as shown in FIG. 4 (A) (maximum). In this case, the grinding feed start position a is closer to the origin position, that is, the position a '(= a ₀ ) separated by the gap q ₀ from the machining end surface Wa position b (= b ₁ ) of the workpiece W. Therefore, the grinding wheel 1 does not collide with the workpiece W during the rapid approach.

Further, as in the above-described embodiment, the grinding feed start position is set in consideration of a large change in the work allowance of the workpiece W due to a change in the lot of the workpiece W or replacement of the grinding wheel 1 and the diamond nib for the dress, a change in the position of the grinding wheel 1, and the like. set the initial position a ₀ of a, if to reset the grinding feed start position a at the initial position a ₀ if there is replacement of lots change or grindstone 1 and the diamond nib dress of the workpiece W, it is possible to omit the trouble of resetting the initial position a ₀ each time there is a lot change of the workpiece W.

In the above embodiment, in order to accurately detect the contact position, the contact position is detected for a plurality of workpieces, and the grinding feed start position is corrected based on the detected contact position. The contact position may be detected for only one workpiece, and the grinding feed start position may be corrected based on the detected contact position.

〔The invention's effect〕

According to the present invention, a position at which a grinding wheel contacts a workpiece is detected by a contact position detecting means, and a difference between a gap between the contact position and a set grinding feed start position and a predetermined target value of the gap is determined. The grinding feed start position is corrected on the basis of the above, so even if the stock removal of the workpiece changes stepwise, the grinding feed start position can always be corrected near the workpiece according to the change. . Therefore, according to the present invention, it is possible to reduce the idle grinding time while preventing the grinding wheel from colliding with the workpiece during the rapid approach, and to improve the machining efficiency.

[Brief description of the drawings]

FIG. 1 is a block diagram showing an embodiment of a grinding feed start position correcting device for a grinding machine according to the present invention, and FIG.
(B) is a flowchart showing a specific example of control, FIG. 3 is a graph showing the relationship between the Z-axis movement amount of the grindstone and time, and FIGS. 4 (A) and (B) are respectively grindstones for the workpiece of the embodiment. 5 (A) and 5 (B) are cross-sectional views showing a positional relationship of a grindstone with respect to a conventional workpiece. 1 ... grinding wheel, 71 ... grinding feed start position setting means, 72 ...
Grinding feed start position correcting means 73, contact position detecting means 73
a: Grinding feed start position, A: Grinding machine, W: Workpiece.

──────────────────────────────────────────────────続 き Continuation of the front page (56) References JP-A-61-252071 (JP, A) JP-A-59-7756 (JP, A) JP-A-64-38666 (JP, A) JP-A-2- 41872 (JP, A) JP 47-23756 (JP, B1) (58) Fields investigated (Int. Cl. ⁶ , DB name) B24B 47 / 22,47 / 25 B24B 49 / 00,49 / 10

Claims (2)

(57) [Claims] An abrading wheel which is rapidly approached to a workpiece to a grinding feed start position set by a grinding feed start position setting means, and is advanced at a predetermined grinding feed speed from the grinding feed start position; In a grinding machine configured to be brought into contact with a workpiece, a position at which the grindstone contacts the workpiece is detected by contact position detecting means, and the detected contact position is set to the grinding feed start position setting means. A grinding feed start position correcting method for a grinding machine, wherein the grinding feed start position is corrected based on a difference between a gap with the grinding feed start position and a predetermined target value of the gap. 2. The method according to claim 1, wherein the grinding wheel is rapidly brought close to the workpiece to a grinding feed start position set by the grinding feed start position setting means, and then advanced at a predetermined grinding feed speed from the grinding feed start position. In a grinding machine configured to be brought into contact with a workpiece, a contact position detecting means for detecting a position at which the whetstone contacts the workpiece, and the detected contact position and the grinding feed start position setting means are set in the grinding machine. Grinding feed start position correcting means for correcting the grinding feed start position based on a difference between the gap with the grinding feed start position and a predetermined target value of the gap. Device for correcting the grinding feed start position of the machine.