JPH08314520A - Numerically controlled grinder - Google Patents

Abstract

PURPOSE: To shorten working time by measuring the diameter dimension of a surface to be ground on a work piece immediately after the start of a cycle, relatively moving a wheel spindle stock to a prescribed position based on the dimension with respect to the work piece, discriminating from which grinding work is started among coarse grinding, precise grinding and micro grinding based on the measured diameter size and executing repairing work. CONSTITUTION: When a repairing cycle command is outputted, an initial diameter measuring means 2 measures the diameter dimensions of the surface to be ground on the work piece W. Then, a fast forwarding means 3 relatively moves the wheel spindle stock with respect to the work piece W by fast forwarding, and it is moved to the prescribed position based on the diameter dimension measured by the initial diameter measuring means 2. A discrimination means 4 discriminates from which grinding work is to be started among coarse grinding, precise grinding and micro grinding based on the diameter dimension measured by the initial diameter measuring means 2. A grinding feed means 5 drives the wheel spindle stock 13 based on the discrimination result of the discrimination means 4 and the repairing work of the work piece W is executed. Thus, the repairing of the work piece W can easily be executed.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a numerically controlled grinder that grinds a work surface by sequentially performing three grinding cycles of rough grinding, fine grinding and fine grinding. The present invention relates to a numerically controlled grinding machine that can easily rework a workpiece that has not been finished to a target size.

[0002]

2. Description of the Related Art With a numerical control grinder such as a cylindrical grinder,
As shown in FIG. 7, the headstock and tailstock centers 15a, 1
Grinding wheel 19 that rotates with respect to the workpiece W supported by 6a
In the grinding process (plunge grinding) for cutting the wheel head having the above, the grinding process is performed by the grinding cycle shown by the thin solid line G in FIG. That is, after the grindstone head is advanced fast forward to the predetermined cutting start position F, the grindstone head is advanced at the rough grinding feed speed to start rough grinding. When rough grinding is started and the grindstone is cut to a predetermined position T, the sizing head of the sizing device is inserted and the outer diameter of the workpiece is measured. Then, the rough grinding is continued until the outer diameter of the workpiece W measured by this sizing device reaches D1 (the workpiece diameter at the time of completion of rough grinding), and when the outer diameter of the workpiece W reaches D1, the grinding stone head. The feed rate of is changed to the fine grinding feed rate and the fine grinding is started. When the fine grinding is continued and the outer diameter of the workpiece W measured by the sizing device reaches D2 (the workpiece diameter when the fine grinding is completed), the feed rate of the wheel head is changed to the fine grinding feed rate and the fine grinding is performed. Be started. When the fine grinding is continued and the outer diameter of the workpiece reaches the finish diameter DF (workpiece diameter when the fine grinding is completed), the grindstone is retracted to complete the grinding process.

[0003]

By the way, in the grinding process in the above-described conventional numerically controlled grinding machine, there are cases in which a work which rarely needs to be reworked is generated. This is because, for example, NC data is mistakenly created and the workpiece diameter after fine grinding is larger than DF by a (
It occurs when the setting is set to d) or the operator interrupts the processing due to an emergency stop due to some abnormality during grinding. Conventionally, the rework of this type of work has been dealt with by the following two means. The first is that the operator performs the rework by manual grinding, and the second is that the above-mentioned normal processing is performed again to perform the rework.

However, the above repair work has the following problems. That is, the rework by the former cannot be easily performed because the operator requires skill, and
There was a variation in the accuracy of the reworked work piece. On the other hand, in the repair work by the latter, as shown by the thick solid line G ′ in FIG. 8, since the fine grinding is started in a state where the air gap immediately after the start of the rough grinding is large, it takes a very long time for the repairing work. That is, the outer diameter dimension a (D2 <a <DF)
When the above-mentioned normal grinding process is performed again on the workpiece, the outer diameter of the workpiece W reaches the workpiece diameter D2 when the fine grinding is completed at the time when the rough grinding is started and the sizing head is inserted. Therefore, the feed rate of the grinding wheel head is changed to the fine grinding feed rate, and the fine grinding is continued in the idle grinding state until the workpiece diameter DF at the time of completion of the fine grinding is reached.

Therefore, it is an object of the present invention to provide a numerically controlled grinding machine which enables easy reworking of a work requiring reworking in a short time.

[0006]

As shown in FIG. 1, the means for solving the above-mentioned problems is to provide a grinding wheel base 13 having a grinding wheel 19 which is driven to rotate, a grinding wheel 19 and this grinding wheel 19. Driving means 1 for relatively moving the grindstone 13 and the workpiece W in a direction in which the workpieces W to be ground come close to and away from each other.
And a measuring device 6 for measuring the diameter of the work surface of the workpiece W.
In a numerical control grinder that changes the feed rate of the grindstone 13 stepwise on the basis of a signal from the measuring device 6 to make the surface to be ground of the workpiece W a finishing diameter, based on the rework cycle command. Initial diameter measuring means 2 for measuring the diameter of the surface of the workpiece W to be processed by the measuring device 6, and the grindstone 13 is set as the workpiece W based on the diameter measured by the initial diameter measuring means 2. On the other hand, a rapid feed means 3 for relatively moving to a predetermined position by rapid feed, and a discriminating means for discriminating from which stage the feed speed of the wheel head 13 is started based on the diameter dimension measured by the initial diameter measuring means 2. 4 and a grinding feed means 5 for driving the driving means 1 based on the discrimination result of the discrimination means 4.

[0007] Similarly, the means of the invention described in claim 2 is a wheel head 13 having a wheel wheel 19 which is driven to rotate,
Grinding wheel 19 and workpiece W to be ground by this grinding wheel 19
Is provided with a drive means 1 for relatively moving the grindstone 13 and the workpiece W in the directions in which the workpiece W approaches and separates from each other, and a measuring device 6 for measuring the diameter dimension of the work surface of the workpiece W. In the numerical control grinder that sequentially changes the rough grinding, the fine grinding, and the fine grinding to make the surface to be ground of the workpiece W a finish diameter, the workpiece W is
The initial diameter measuring means 2 for measuring the diameter of the surface to be processed by the measuring device 6, and the grindstone base 13 is fast-forwarded to the workpiece W based on the diameter measured by the initial diameter measuring means 2. Based on the diameter dimension measured by the initial diameter measuring means 2 and the rapid feeding means 3 for relatively moving to a predetermined position by the discriminating means 4 for discriminating which of the rough grinding, the fine grinding or the fine grinding is to start the processing. And a grinding feed means 5 for driving the driving means 1 based on the discrimination result of the discrimination means 4.

[0008]

When the rework cycle command is output, the initial diameter measuring means 2 measures the diameter of the surface to be ground of the workpiece W. Then, the grindstone 13 is moved to the workpiece W by the fast-forwarding means 3.
Is relatively fast-moved toward and is moved to a predetermined position based on the diameter dimension measured by the initial diameter measuring means 2. Further, the discriminating means 4 discriminates which of the rough grinding, the fine grinding and the fine grinding should be started based on the diameter dimension measured by the initial diameter measuring means 2. Then, based on the determination result of the determination unit 4, the grinding feed unit 5 drives the grindstone base 13 to rework the workpiece W.

[0009]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 2 is an overall configuration diagram of a numerically controlled grinding apparatus that is an embodiment of the present invention. On a work table 12 that is guided and supported on a bed 11 of a grinding machine 10 so as to be movable in the left-right direction (Z direction), a headstock 14 that supports a spindle 15 and a tailstock 1.
6 are provided facing each other in the left-right direction, and the work W has a spindle 15
Both ends are supported by centers 15a, 16a provided on the tailstock 16. The spindle 15 is rotationally driven by a motor 18 provided on the spindle stock 14, and the work W has a spindle 1 at the left end.
5 is engaged with a detent member 17 protruding from the main shaft 15
Is rotated with.

A grindstone 13 is guided and supported on the bed 11 so as to be movable in a horizontal X direction orthogonal to the Z direction, and a grindstone 19 is mounted on the grindstone 13 so that the grindstone shaft 20 is parallel to the main shaft 15. V-belt rotation transmission mechanism 21 supported by
It is rotationally driven by the motor 22 via. Bed 11
Servo motor 23 and servo motor 26 provided in
Digital servo unit 41 and digital servo unit 4 which operate based on a command signal from the numerical controller 30
2 are controlled and driven by a feed screw device (not shown) to feed the grindstone 13 in the X direction and feed the work table 12 in the Z axis direction. Position detectors 25 and 27 such as encoders detect the moving positions of the grindstone 13 and the workpiece table 12 via the rotation angles of the servomotors 23 and 26, and the detected values are input to the digital servo units 41 and 42, respectively. In addition to being feedback-controlled, it is input to the numerical controller 30 via an amplifier (not shown). The digital servo units 41, 42 described above
The driving means 1 is constituted by the servo motors 23 and 26.

Further, at a position facing the grinding wheel 19 on the bed 11, a sizing head 2 for measuring the outer diameter of the workpiece W is provided.
4 is arranged, and a pair of feelers 2 of this sizing head 24
4a (only the upper feeler is shown in the figure) holds the workpiece W. This sizing head 24 is a head feeding device 2
By means of 8, the workpiece W is moved forward to a predetermined position during machining, and is retracted in a direction away from the workpiece W when exchanging the workpiece W or the like. The sizing head 24 is configured to send an outer diameter signal corresponding to the outer diameter of the workpiece W to the numerical controller 30 via an A / D converter (not shown). The head feeding device 28
Is driven by a command signal from the numerical controller 30. The sizing head 24 constitutes the measuring device 6.

As shown in FIG. 2, the numerical control device 30 has a
Central processing unit (CP that controls and manages the entire grinding machine 10
U) 31, a memory 32, and an interface 33 for exchanging data with the outside. Memory 32
The normal machining program 32a that grinds the workpiece W in a normal cycle, and the characteristic reworking program 32b of the present invention are stored in the NC program, and machining NC data input from an NC data creating device 70 described later is stored. Remember N
The C data storage area 32c and an initial outer diameter storage area for storing an outer diameter dimension of a workpiece W described later are secured.

The interface 33 includes digital servo units 41 and 42, position detectors 23 and 27, and
The head feed device 28, the operation panel 50, and the NC data creation device 70 are connected. Digital servo unit 4
The grindstone base 13 and the work table 12 are driven by outputting command signals to the Nos. 1 and 42, and the positions of the grindstone base 13 and the work table 12 at that time are input from the position detectors 23 and 27, respectively. It By outputting a command signal to the head feeding device 28, the sizing head 24 is driven to move back and forth to a desired position. An outer diameter signal corresponding to the outer diameter dimension of the workpiece W measured as described above is input from the measuring head 24, and the feed speed of the grinding wheel head 13 is switched according to the outer diameter signal. It is like this.

The operation panel 50 has a display device 51 for displaying a machining state and NC data, a keyboard 52 for correcting NC data and inputting various parameters, a normal cycle start button 53, and a rework cycle start button 54. Composed of and. The normal cycle start button 53 is pressed when the workpiece W, which has been normally processed in the previous process, is ground in a normal grinding cycle, whereby the memory 32 is pressed.
The normal machining program 32a stored in is executed to grind the workpiece W. The rework cycle start button 54 is pressed when rework processing is required for the workpiece W machined by the normal grinding cycle. When the rework cycle activation button 54 is pressed, the memory 32
The reworking program 32b, which will be described later and is stored in, is executed.

The NC data creating device 70 is a device for automatically creating NC data for machining by giving parameters such as the finish diameter and surface roughness of the workpiece W, and numerically controls the created NC data. It is designed to be sent to the device 30. The NC data sent is the numerical controller 3
The memory 32 is stored in the NC data storage area 32c of the second memory 32.

Next, the operation of the numerically controlled grinding machine of this embodiment constructed as described above will be explained. Now, in the NC data storage area 32c of the memory 32, the NC data creation device 70
It is assumed that the NC data created in 1. is stored. The worker mounts the workpiece W, which has been normally processed in the previous process, between the centers 15a and 16a on the workpiece table 12, and presses the normal cycle start switch 53 of the operation panel 50. Then, the normal machining program 32a stored in the memory 32 of the numerical control device 30 is executed, and the grinding process by the same grinding cycle as the conventional one shown by the thin solid line G in FIG. 8 is started. That is, after the grindstone base 13 is advanced to the predetermined cutting start position F by rapid feed, the grindstone base 13 is advanced at the rough grinding feed speed to start rough grinding. When rough grinding is started and the grindstone is cut to a predetermined position T, the numerical control device 30 drives the head feeding device 28 to move the sizing head 24 forward to a predetermined position to measure the outer diameter of the workpiece W. To start. The outer diameter of the workpiece W measured by the sizing head 24 while the rough grinding is continued is the workpiece diameter D when the rough grinding is completed.
When the value reaches 1, the numerical control device 30 changes the cutting speed of the wheel head 30 to the fine grinding feed speed and starts the fine grinding. Workpiece W measured by the sizing head 24 after fine grinding is continued
When the outer diameter dimension of reaches the workpiece diameter D2 at the time of fine grinding completion, the numerical controller 30 changes the cutting speed of the wheel head 30 to the fine grinding feed speed and starts fine grinding. Then, the fine grinding is continued, and the outer diameter of the workpiece W is the work diameter DF when the fine grinding is completed.
When the (finishing diameter) is reached, the numerical control device 30 causes the wheel head 13
And the measurement head 24 are retracted to complete the grinding process.

In this way, the workpiece W processed in the above-mentioned normal grinding cycle is ground to the target finish diameter,
For example, it is assumed that a workpiece W that needs to be reworked with the machining allowance Δd left without being ground to the target finish diameter is generated due to some abnormality during the normal grinding cycle.
In this case, the operator again attaches the work W requiring the rework between the centers 15a and 16a of the work table 12, and presses the rework cycle start button 54 of the operation panel 50. Then, the retouching program 32b, which will be described later, is executed to perform the retouching.

Here, the operation of the reworking by the reworking cycle, which is a characteristic of the present invention, will be described in detail with reference to the flowchart showing the reworking program 32b of FIG. 3 and the explanatory diagrams of FIGS. 4 to 5. When the repair cycle start button 54 is pressed, the numerical controller 30 drives the motor 18 to rotate the workpiece W at a predetermined rotation speed,
Step 102 is executed.

In step 102, first, in order to measure the outer diameter of the workpiece W, the head feeding device 28 is driven to advance the sizing head 24 to a predetermined position. Outer diameter a of the workpiece W measured by the sizing head 28 in step 104
Is input through the sizing device 60 and stored in the initial outer diameter storage area 32d of the memory 32. This step 102, 10
4 constitutes the measuring means 2.

At step 106, it is judged whether or not the repair cycle is to be executed. That is, the size of the outer diameter dimension a stored in step 104 is compared with the size of the workpiece diameter DF (finish diameter) at the completion of fine grinding. a
== DF, the attached workpiece W has a finishing diameter DF
It is discriminated that it has reached, and the following steps are not executed and the process ends. When a> DF, the workpiece W has a finishing diameter D.
Since it has not reached F, it is determined that a repair cycle is necessary, and the process proceeds to the subsequent step 108. Further, in the case of a <DF, the workpiece W is smaller than the finishing diameter DF, so it is determined that there is an abnormality due to excessive cutting, the process proceeds to step 128, and a display indicating the abnormality is displayed on the display device 51 of the operation panel 50. The abnormal processing is performed and the processing ends abnormally.

At step 108, the memory 32
The grindstone base 13 is fast-forwarded until the tip of the grinding wheel 19 is located at a position where a predetermined amount α is added to the outer diameter dimension a of the workpiece W stored in the initial outer diameter storage area 32d. This step 108 constitutes the fast-forwarding means 3. Subsequently, in step 110, the size of the outer diameter dimension a of the workpiece W stored in step 104 and the workpiece diameter D2 when the fine grinding is completed are compared. a> D2
In the case of, it moves to step 112, and in the case of a ≦ D2, it moves to step 122. When the process proceeds to step 112, the size of the outer diameter dimension a of the workpiece W stored in step 104 and the workpiece diameter D1 at the completion of rough grinding are compared. If a> D1, the process proceeds to step 114, where a ≦
In the case of D2, the process proceeds to step 118. That is,
In steps 110 and 112, it is determined which of the rough grinding, the fine grinding, and the fine grinding is to be started. These steps 110 and 112 are the determination means 4
Is composed.

When the process proceeds to step 114, the grindstone base 13
The rough grinding is started by changing the feed rate of the workpiece to the rough grinding feed rate, and it is determined in step 116 whether or not the outer diameter of the current workpiece W has reached the workpiece diameter D1 at the time of completion of rough grinding. The rough grinding in step 114 is continued until the outer diameter of W reaches the workpiece diameter D1 when the rough grinding is completed. When the current outer diameter of the workpiece W reaches the workpiece diameter D1 at the time of completion of rough grinding and the process proceeds to step 118, the feed speed of the wheel head 13 is changed to the fine grinding feed speed to start fine grinding. Then, in step 120, the fine grinding in step 118 is continued until the outer diameter of the current work W reaches the work diameter D2 at the time of completion of the fine grinding.

Further, when the current outer diameter of the workpiece W reaches the workpiece diameter D2 at the time of completion of fine grinding and the process moves to step 122, the feed speed of the wheel head 13 is changed to the fine grinding feed speed to start fine grinding. To do. Then, in step 124, the fine grinding in step 122 is continued until the current outer diameter of the workpiece W reaches the workpiece diameter DF (finishing diameter) at the time of completion of fine grinding.
When the outer diameter of the workpiece W reaches the finishing diameter DF, step 12
6, the numerical control device 30 retracts the grindstone base 13 and retracts the sizing head 24 to complete the grinding process of the repair cycle.

When it is determined in step 112 that a≤D1, the process proceeds to step 118 to start rough grinding, and when it is determined in step 110 that a≤D2, proceeds to step 122. Fine grinding is started. Therefore, according to the rework cycle described above, for example, as shown by the thick solid line G1 in FIG. 4, the workpiece having the outer diameter a1 which is larger than the finishing diameter DF (the workpiece diameter when the fine grinding is completed) by the machining allowance Δd1. Regarding the reworking cycle of W, in step 108, the grindstone base 13 is advanced by rapid feed to the position of a1 + α, and fine grinding is performed from this position until the outer diameter of the workpiece W reaches the workpiece diameter DF when the fine grinding is completed. Is done and reworking is performed. Further, as indicated by the thick solid line G2 in FIG. 5, the outer diameter a2 which is larger than the finishing diameter DF by the machining allowance Δd2.
Regarding the rework cycle of the workpiece W (larger than the outer diameter D2 of the workpiece when the fine grinding is completed), in step 108, a
The grindstone 13 is advanced to the position of 2 + α by fast-forwarding, and fine grinding is performed from this position in step 118 until the outer diameter of the workpiece W reaches the workpiece diameter D2 when the fine grinding is completed. Then, in step 122, fine grinding is performed until the outer diameter of the workpiece W reaches the workpiece diameter DF at the time of completion of fine grinding, and reworking is performed. Further, as shown by a thick solid line G3 in FIG. 6, for the rework cycle of the workpiece W having an outer diameter a3 (larger than the workpiece outer diameter D1 at the completion of rough grinding) which is larger than the finishing diameter DF by the machining allowance Δd3, 108
At this point, the grindstone base 13 is rapidly advanced to the position of a3 + α, and rough grinding is performed from this position until the outer diameter of the workpiece W reaches the workpiece diameter D1 at the completion of rough grinding in step 114. Then, similarly, fine grinding and fine grinding are sequentially performed to perform reworking. As described above, the numerically controlled grinding machine according to the present embodiment has the following effects because the machining of the rework cycle is provided. That is, the outer diameter dimension a of the workpiece W to be reworked is measured by the sizing head 24, and the grindstone 13 is fast-forwarded to a position where a predetermined amount α is added to the measured outer diameter dimension a, so that the work piece is reworked in a short time. Can be processed. Further, since it is determined which of the rough grinding, the fine grinding, and the fine grinding is to be performed according to the measured outer diameter dimension a, the machining is performed. Therefore, the NC program is modified or the sizing point is changed. Rework can be done easily without any work. In addition, the sizing head 24 is the same as in the ordinary grinding process.
Since it is directly machined by sizing, it can be reworked with high accuracy.

In the present embodiment, an example of a numerical control grinder that grinds a workpiece by three grinding cycles of rough grinding, fine grinding and fine grinding has been described, but the grinding cycle is not limited to this. Rough grinding and fine grinding 2
A grinding machine that grinds in one grinding cycle and precision grinding are the first
The present invention can be implemented in a grinding machine having a grinding cycle divided into fine grinding and second fine grinding. Moreover, although the cylindrical grinder that grinds the outer periphery of the workpiece W has been described in the above-described embodiments, an inner surface grinder that grinds the inner peripheral surface of the workpiece W can also be implemented.

[0026]

As described above, the numerically controlled grinding machine of the present invention measures the radial dimension of the work surface to be ground immediately after the start of the cycle, and fast-forwards to a predetermined position based on the measured radial dimension. Move the whetstone base relative to the workpiece,
Based on the measured diameter dimension, it is possible to perform the reworking of the workpiece by discriminating which of the rough grinding, the fine grinding and the fine grinding to start the working, so that the reworking can be easily performed in a short time. effective.

[Brief description of drawings]

FIG. 1 is a diagram corresponding to a claim of the present invention.

FIG. 2 is an overall configuration diagram of a numerical control grinding machine showing an embodiment of the present invention.

FIG. 3 is a flowchart showing the operation of the reworking program.

FIG. 4 is an explanatory diagram showing a repair cycle.

FIG. 5 is an explanatory diagram showing a repair cycle.

FIG. 6 is an explanatory diagram showing a repair cycle.

FIG. 7 is a partially enlarged view showing an example for carrying out the present invention.

FIG. 8 is an explanatory diagram showing a conventional rework cycle.

[Explanation of symbols]

 10 Grinding machine 13 Grinding wheel base 19 Grinding wheel 23,26 Servo motor 24 Sizing head 28 Head feeding device 30 Control device 31 CPU 32 Memory 41,42 Digital servo unit 50 Operation panel W Workpiece

Claims (2)

[Claims] 1. A grindstone having a grindstone wheel driven to rotate, a driving means for relatively moving the grindstone base and the workpiece in a direction in which the grindstone and a workpiece ground by the grindstone approach and separate from each other. And a measuring device for measuring the diameter dimension of the work surface of the workpiece, and the feed speed of the grindstone is stepwise changed based on a signal from the measuring device to grind the work surface of the workpiece. In the numerical control grinding machine to make the finishing diameter, the initial diameter measuring means for measuring the diameter dimension of the work surface of the workpiece based on the rework cycle command, and the initial diameter measuring means. Based on the diameter, the rapid movement means for relatively moving the grindstone base relative to the workpiece to a predetermined position with respect to the workpiece, and the feed of the grindstone base based on the diameter dimension measured by the initial diameter measuring means. What stage of speed A numerical control grinding machine, comprising: a discriminating unit that discriminates whether to start from a start position, and a grinding feed unit that drives the driving unit based on a discrimination result of the discriminating unit. 2. A grindstone having a grindstone wheel that is driven to rotate, a driving means that relatively moves the grindstone base and the workpiece in a direction in which the grindstone and a workpiece ground by the grindstone approach and separate from each other. And a measuring device for measuring the diameter of the work surface of the workpiece, and the grinding surface of the workpiece is sequentially changed to rough grinding, fine grinding and fine grinding based on a signal from the measuring device. In the numerical control grinding machine to make the finishing diameter, the initial diameter measuring means for measuring the diameter dimension of the work surface of the workpiece based on the rework cycle command, and the initial diameter measuring means. Based on the diameter dimension measured by the initial diameter measuring means and the rapid feed means for relatively moving the grindstone base relative to the workpiece to a predetermined position by rapid feed, based on the diameter dimension, the rough grinding, precise Grinding and fine grinding A numerically controlled grinding machine comprising: a discriminating means for discriminating from which of the two, machining is started, and a grinding feed means for driving the driving means based on a discrimination result of the discriminating means.