JP3203850B2 - Grinding equipment - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a grinding machine for grinding a workpiece using a grindstone, and more particularly to a grinding machine capable of performing a grinding process while maintaining the shape of a grindstone in an appropriate state.

[0002]

2. Description of the Related Art In grinding, dressing (grinding) and truing (forming) the grindstone is a major factor influencing the machining efficiency and machining accuracy.
Conventionally, many inventions and ideas have been devised.

[0003] In particular, in the method of truing (forming), the method disclosed in Patent Application Publication No. 2-38346 discloses that a grinding wheel can be formed on an NC machine tool by electric discharge machining using a traveling wire. The need for removal is eliminated, and efficiency and accuracy have been greatly improved. However, since this method is based on a device that performs grinding by attaching a grindstone to an NC machine tool, movement for performing electric discharge machining is performed by a grindstone controlled by the NC device.
Therefore, although it is not necessary to remove the grindstone, processing must be interrupted each time the grindstone is required to be formed, and the grindstone must be moved to a position where the wire traveling device is installed to perform the molding. Therefore, work efficiency decreases and
There has been a problem that the positioning error caused by moving the grindstone over a long distance increases, and the processing accuracy decreases.

On the other hand, a method of applying a voltage by moving an electrode placed in the vicinity of a grindstone in two axial directions is disclosed in Japanese Patent Laid-Open Publication No. 3-196.
968. In this method, since a metal plate is used for the electrode, the electrode and the grindstone are consumed, and the shape of the grindstone cannot be detected. Therefore, this method is effective mainly for dressing (sharpening), but cannot expect the ability of truing (forming) to give a desired shape to a grindstone with high accuracy. That is, conventionally, it has been thought that the truing (forming) of the grindstone cannot be performed during the grinding of the work because the shape of the working surface of the grindstone changes during the grinding of the work with the grindstone. The present inventor has studied a method of performing truing (forming) of a grindstone according to a change in the shape of the working surface of the grindstone during grinding of a workpiece with the grindstone. As a result, when the grindstone is formed by electric discharge machining, an electric discharge machining apparatus is used. It has been found that by devising the control method, the truing (forming) of the grindstone can be easily performed according to the shape change of the working surface of the grindstone during the grinding of the work.

[0005]

SUMMARY OF THE INVENTION The present invention has been made in view of the above circumstances and examination results, and has as its object the contents described in the following (O01). (O01) To enable high-precision grinding without interrupting grinding when grinding a workpiece with a grindstone.

[0006]

Next, the present invention devised to solve the above-mentioned problems will be described. Elements of the present invention are used to facilitate correspondence with elements of the embodiments described later. , The reference numerals of the elements of the embodiment are enclosed in parentheses. The reason why the present invention is described in correspondence with the reference numerals of the embodiments described below is to facilitate understanding of the present invention, and not to limit the scope of the present invention to the embodiments.

[0007] In order to solve the above problems, the first of the present application
The grinding apparatus of the present invention has the following requirements (Y01) to (Y04)
It is characterized by having. (Y01) a grindstone supporting member that rotatably supports a grindstone (2) for grinding the work (W) and is relatively movable with respect to the work (W); A work processing control device for controlling the relative movement of the grindstone (2) and grinding the work (W) with the grindstone (2); (Y03) being held in a predetermined positional relationship with respect to the grindstone support member; A grinding wheel forming device supporting member (3), (Y04) a two-axis supported by the grinding wheel forming device supporting member (3) and movable in a width direction of a working surface of the grinding wheel (2) and in a direction perpendicular to the working surface. A wire electrode (13) for electric discharge machining runs along a table (6), a wire guide (12) supported by the biaxial table (6), and a guide groove formed on the outer periphery of the wire guide (12). Wire traveling device for causing During the grinding of the work (W) according to 2), the grinding of the grinding wheel (2) is carried out simultaneously by the electric discharge machining between the grinding wheel (2) and the wire electrode (13) according to the shape of the working surface of the grinding wheel (2). A grindstone forming device (4) for performing a grindstone forming means for forming the shape of the grindstone (2) by electric discharge machining.

The grinding apparatus according to the second invention of the present application is
In the grinding apparatus of the first invention, the following requirement (Y
(Y05) The grindstone forming means having working surface shape detecting means for detecting the shape of the working surface of the grinding wheel (2).

The grinding apparatus according to the third invention of the present application is
In the grinding device of the second invention, the following requirement (Y
(Y06) detecting the discharge start position of the wire electrode (13) with respect to a plurality of positions in a direction transverse to the moving direction of the working surface of the grinding wheel (2), The operation surface shape detecting means for detecting the shape of the operation surface in 2).

[0010]

Next, the operation of the present invention having the above-mentioned features will be described. In the grinding device of the first invention of the present application having the above-described features, the movement of the grindstone support member is controlled relative to the work (W) by the work processing control device. In this case, the relative movement between the work (W) and the grindstone support member can be arbitrarily selected whether to move the work (W) or the grindstone support member. The work (W) is ground by a grindstone (2) rotatably supported by the grindstone support member. The grindstone forming device support member (3) held in a predetermined positional relationship with respect to the grindstone support member includes:
A biaxial table (6) of the grinding wheel forming device (4) is supported. The biaxial table (6) is movable in the width direction (Y1-Y2 direction) of the working surface of the grinding wheel (2) and in the direction (Z1-Z2 direction) perpendicular to the working surface. The wire traveling device supported by the biaxial table (6) travels a wire electrode (13) for electric discharge machining along a guide groove formed on the outer periphery of the wire guide (12). The wire electrode (13) is for forming the grinding wheel (2).

The grinding wheel (2) is formed by the wire electrode (13) according to the shape of the working surface of the grinding wheel (2) while the work (W) is ground by the grinding wheel (2).
Is subjected to electric discharge machining for molding. That is, while forming the grindstone (2) by the electric discharge machining, the work (W) is ground by the grindstone (2) at the same time.

The electric discharge machining of the grindstone (2) using the wire electrode (13) can always be performed using an electrode having a predetermined shape (an electrode whose shape does not change). Further, since the electric discharge machining is employed, the position or the shape of the working surface of the grindstone (2) with respect to the wire electrode (13) can be accurately detected by detecting the current flowing through the wire electrode (13). As described above, since the workpiece (W) can be ground in a state in which the position or shape of the working surface of the grindstone (2) is accurately known, high-precision grinding can be performed. In addition, since the forming of the grindstone (2) is simultaneously performed while performing the grinding of the work (W), the grinding of the work (W) can be performed while maintaining the shape of the grindstone (2) with high accuracy. it can. Therefore, the work (W) can be ground with high precision, and the grinding wheel (2) can be formed without interrupting the work grinding. Therefore, it is possible to improve work efficiency.

In the grinding apparatus according to the second aspect of the present invention having the above-described features, the shape of the working surface of the grinding wheel (2) is detected by the working surface shape detecting means. In accordance with the shape of the working surface of the grindstone (2) detected by the working surface shape detection means, the grinding wheel (2) is simultaneously ground by the wire electrode (13) while the work (W) is being ground by the grindstone (2). Electric discharge machining for the molding of 2) is performed. Since the second invention detects the shape of the working surface of the grinding wheel (2), it is possible to always keep the shape of the working surface of the grinding stone (2) in an optimum state.

In the grinding apparatus according to the third aspect of the present invention having the above-mentioned features, the working surface shape detecting means may detect the working surface shape in the direction (Y1-Y2 direction) transverse to the moving direction of the working surface of the grinding wheel (2). The shape of the working surface of the grinding wheel (2) is detected by detecting the discharge start position of the wire electrode (13) at a plurality of positions. Since the position of the wire electrode (13) is determined by the position of the biaxial table (6) of the first invention,
It can be easily detected. If the position of the wire electrode (13) when the discharge is started can be detected at a plurality of positions in the direction (Y1-Y2 direction) crossing the moving direction of the working surface of the grinding wheel (2), the position of the wire electrode (13) The position of the working surface of the grinding stone (2) at a predetermined position close to the position can be easily detected. This third invention is
The shape of the working surface of the grindstone (2) depends on the position of the wire electrode (13) (ie, the position of the biaxial table (6)) when the current flowing through the wire electrode (13) is detected, that is, when the discharge is performed. Is measured. That is, the shape of the working surface of the grindstone (2) is detected by using the components of the grindstone forming device (4) without newly providing a shape detecting device for the working surface of the grindstone (2). For this reason, the whetstone (2)
There are few new elements required for shape detection.
An increase in cost can be prevented.

[0015]

Next, embodiments of the present invention will be described with reference to the drawings, but the present invention is not limited to the following embodiments. (Embodiment 1) In FIG. 1, those in which “•” is described in “O” mean an arrow pointing from the back of the paper to the front,
A mark with "x" in "o" means an arrow pointing from the front to the back of the paper. In the description of the first embodiment of the present invention, “forward” means the direction of arrow X1 in the figure, and “rear” means the direction of arrow X2 (see FIG. 1) in the figure. Further, "left" means the direction of the arrow Y1 in the figure (see FIG. 1), that is, the direction of the left hand side when facing from "the rear" to "front", and "right" means the arrow Y2 in the figure. It means direction. Further, "upper" is Z1 in the figure.
"Downward" means the Z2 direction in the figure.

In FIG. 1, a work supporting table T is supported by a processing machine main body H so as to be movable in a front-rear direction (X1-X2 direction), a left-right direction (Y1-Y2 direction), and a vertical direction (Z1-Z2 direction). Have been. The work W is fixedly supported on the work support table T. A grindstone support member (not shown) is fixed to the processing machine main body H.
The grinding wheel support member is formed separately from the processing machine main body H, but may be formed integrally. The grindstone support shaft 1 is rotatably supported by the grindstone support member (not shown). The grindstone 2 is supported by the grindstone support shaft 1. The grindstone support shaft 1 is made of a conductive material for supplying discharge power to the grindstone 2. In order to relatively move the grindstone support member (not shown) and the work supporting table T, instead of adopting the configuration of moving the work supporting table T as in this embodiment,
For example, it is also possible to fix the work supporting table to the processing machine main body H and movably support the grinding wheel support member. The rotation of the grinding wheel support shaft 1 and the movement of the work support table T are controlled by a conventionally known work processing control device (not shown).

In FIGS. 1 and 2, the processing machine main body H has a grindstone forming device held in a predetermined positional relationship with a grindstone support member (not shown) for rotatably supporting the grindstone support shaft 1. A support member 3 is provided. A grindstone forming device 4 that forms the shape of the grindstone 2 by electric discharge machining is supported by the grindstone forming device support member 3. The grinding wheel forming device 4 has a biaxial table driving device 5 and a biaxial table 6 driven by the biaxial table driving device 5. The biaxial table 6 is supported by the grindstone forming device support member 3 and has a vertical direction (Z1-Z2 direction) and a horizontal direction (Y1
−Y2 direction). The wire traveling system support substrate 7 supported by the biaxial table 6 is formed of an insulating ceramic material, and as shown in FIGS. Width direction (Y1-
(Y2 direction) and a direction (Z1-Z2 direction) perpendicular to the working surface.

A wire feed bobbin 8, a wire winding bobbin 9, a brake roll 1
1, a wire guide 12 and the like are rotatably supported.
The wire guide 12 is a conductive super hard product. The electrode wires 13 sent out from the wire feeding bobbin 8 by a conventionally known wire running device (not shown) are sequentially guided by the brake roll 11, the wire guide 12, and the brake roll 11, and are wound around the wire take-up bobbin 9. It is designed to be wound up. Discharge power is supplied to the electrode wire 13 from the wire guide 12. A nozzle 14 for supplying an electric discharge machining liquid between the electrode wire 13 and the work W is supported by the wire traveling system support substrate 7. The electric discharge machining liquid supplied from the nozzle 14 is water whose electric resistance has been increased by performing ion exchange.

In FIG. 1, a biaxial table driving device 5 for moving the biaxial table 6, a table driving device 16 for moving the work supporting table T, a grindstone driving device 17 for rotating the grindstone support shaft 1, The wire driving device 19 for driving the wire traveling device (not shown) and the electric discharge machining power supply device 21 are controlled by the computer C. The electric discharge machining power supply device 21 uses a so-called micro electric discharge machining power supply of an energy storage type.
The electric discharge machining power supply device 21 has a function of supplying electric discharge power to the grindstone 2 and the electrode wire 13 via the conductive grindstone support shaft 1 and the wire guide 12. The electric current when the discharge was performed between the grinding wheel 2 and the electrode wire 13 was A /
The signal is converted into a digital signal by the D converter 22 and input to the computer C.

Next, referring to FIG.
The fact that the shape of the working surface of the grinding wheel 2 can be detected by the grinding wheel forming device 4, the electric discharge machining power supply device 21, the A / D converter 22, and the like will be described. The biaxial table 6 is moved by the computer C, and the wire guide 1 is moved from the radial direction of the grindstone 2.
The electrode wire 13 running while being guided by the guide wheel 2 is brought closer to the grindstone 2. At that time, if the electric discharge machining power supply device 21 is kept in a machining state, electric discharge occurs when the distance between the surface of the conductive grindstone 2 and the electrode wire 13 becomes short and becomes equal to or lower than the dielectric strength of the electric discharge machining liquid. The discharge current is measured by measuring means (not shown) provided in the electric discharge machining power supply 21, and is further input as a digital signal to the computer C by the A / D converter 22 to detect the occurrence of electric discharge. By recording the position of the biaxial table 6 at that time, the position of the surface of the grindstone can be detected.

As shown in FIG. 4, the above operation is repeated from the one end face of the grindstone 2 at regular intervals, and is repeated to the other end face, so that the entire surface shape of the grindstone 2 in the width direction (Y1-Y2 direction, ie, the left-right direction) is obtained. Can be detected. Therefore, the computer C, the grinding wheel forming device 4, the electric discharge machining power supply device 21, the A / D converter 22, and the like constitute a working surface shape detecting means for detecting the shape of the working surface of the grinding wheel 2.

When the shape of the working surface of the grindstone 2 is detected as described above, the entire working surface can be subjected to electrical discharge machining in accordance with the most worn portion of the working surface of the grindstone 2. The electric discharge machining of the working surface of the grindstone 2 can be performed by the computer C, the grindstone forming apparatus 4, the electric discharge machining power supply 21 and the like. That is, in this embodiment, means for forming the grinding wheel 2 of the present invention is constituted by the computer C, the grinding wheel forming device 4, the electric discharge machining power supply device 21 and the like. As a result of the electric discharge machining, the working surface of the grindstone 2 becomes a newly formed ideal shape. At that time, the diameter of the new working surface of the grindstone 2 decreases by the amount of the electric discharge machining in the radial direction of the grindstone 2. If the path of the working surface of the grindstone 2 corrected by the reduced amount is calculated and the movement of the work supporting table T is controlled, the work W can be processed with high accuracy.
Although the forming operation of the grindstone 2 is basically a step operation, it is an operation that is always performed during the processing of the work W, so that the distance between the old and new working surfaces of the grindstone 2 is extremely small, for example, about 0.1 μm. . Therefore, since the forming operation of the grindstone 2 is not substantially different from the continuous operation, the forming operation of the grindstone 2 and the grinding of the workpiece W are performed simultaneously.

(Operation of the First Embodiment) Next, the operation of the grinding apparatus of the first embodiment having the above-described configuration will be described with reference to the flowcharts of FIGS. FIG. 5 is a grindstone forming flow performed before the processing of the work W is started, and FIG. 6 is a flow at the time of processing the work W. The processing of the flowchart in FIG. 5 is performed by the judgment of the worker, and the processing of the flowchart in FIG. 6 is performed according to a program stored in the ROM of the microcomputer M (computer C).

In FIG. 5, when the flow of forming a grindstone before machining a work is started, the grindstone 2 is mounted on the grindstone support shaft 1 in step S1. Next, step S
At 2, the balancer performs the first balance. This first balancing is performed at a lower rotation speed than the second balancing described later. In the balancing, an unbalance amount measuring device called a balancer is used. In this unbalance amount measuring device, an instruction is given to "add a weight of what g to which part of the central axis". So, attach a screw-in weight,
Place the balance again and repeat the process until the desired balance is achieved. Next, in step S3, the outer periphery is deflected. In the outer peripheral run-out in step S2, for example, a grinding operation is performed on the grindstone 2 by performing an operation of shaving a block of alumina particles, which is called a white stick, for example. However, in this method, a runout of about 5 to 10 μm remains. Next, in step S4,
A second balance is performed by the balancer.
The second balancing is performed more carefully while rotating the grindstone 2 at a higher speed than in the first balancing.

In step S5, the grinding wheel 2 is formed by electric discharge machining. At the time of the electric discharge machining, the electrode wire 13 travels and always becomes a new surface.
The position of the three surfaces is not changed by the processing. Therefore,
High-precision forming of the grindstone 2 can be performed. Next, in step S6, it is determined whether or not the shape accuracy is equal to or less than an allowable value. As described with reference to FIG. 4, the determination is repeated by measuring the position of the surface of the grinding wheel 2 from one end to the other end in the width direction of the surface of the grinding wheel 2. It depends on whether it is within the accuracy range. If no (N) in step S6, the process returns to step S5. In the case of Yes (Y), the forming flow of the grindstone 2 before processing the work W is ended.

The grindstone 2 before processing the work W shown in FIG.
After the completion of the molding flow, the processing flow of the workpiece W shown in FIG. 6 is executed. In FIG. 6, when the work processing flow is started, the processing of the work W by the grindstone 2 is started in step S11. Next, in step S12,
The shape of the grindstone is measured by the grindstone forming device 4. The shape measurement of the grindstone 2 is performed by the method described with reference to FIG. That is, since the electric discharge occurs through a certain gap (a gap of about 1 μm to 10 μm depending on the type of the power supply and the machining fluid), the position of the table at that time is monitored, and the truing speed and the current value are monitored. Measure the grindstone diameter.

Next, in step S13, it is determined whether a change in the shape of the grindstone 2 has been sensed. This determination is made based on whether the measured shape of the grindstone 2 is within a predetermined range of the shape accuracy of the grindstone 2. No (N) in step S13
In the case of, the process moves to step S14, and the processing of the work W is continued. If the answer is yes (Y) in step S13, the process moves to step S15. In step S15, the grinding wheel 2 is formed. Next, in step S16, N
After correcting the C control data, the process proceeds to step S14.
In step S14, the work W is processed based on the NC control data corrected according to the new shape.

After step S14, the process proceeds to step S17. In step S17, it is determined whether machining of the workpiece is completed. If no (N), the process returns to step S12. If yes (Y), the processing of the workpiece W ends.

According to the first embodiment, the processing of the work W is not interrupted and the grindstone 2 is not moved.
Since the grinding wheel 2 can be formed during work processing and the electric discharge machining is performed with the traveling wire (electrode wire) 13 whose wear is canceled, the grinding wheel 2 is extremely efficient and highly accurate.
Can be formed. Further, in this embodiment, since the grindstone forming device 4 itself moves and the grindstone 2 itself does not need to move, there is an advantage that the present invention can be applied to a general grinding machine having no function of moving the grindstone by NC control.

(Embodiment 2) Next, Embodiment 2 of the grinding apparatus of the present invention will be described with reference to FIG. In the description of the second embodiment, components corresponding to the components of the first embodiment are denoted by the same reference numerals, and detailed description thereof will be omitted. FIG. 7 shows an example in which this method is applied to a cup-shaped grindstone 2. As in the case of the disc-shaped grindstone of the first embodiment, the width direction (Y1-Y2 direction) of the working surface of the cup-shaped grindstone 2 is used.
The working surface of the cup-shaped grindstone 2 is formed into a desired shape by moving the wire traveling system support substrate 7 in a direction (Z1-Z2 direction) perpendicular to the working surface of the cup-shaped grindstone 2 and performing electric discharge machining. be able to. Further, in this case, the operation position of the cup-shaped grindstone 2 can be known by giving feedback of the discharge current, as in the first embodiment.

(Modifications) Although the embodiments of the present invention have been described in detail, the present invention is not limited to the above-described embodiments, but falls within the scope of the present invention described in the appended claims. Thus, various changes can be made. Modified embodiments of the present invention are exemplified in the following (H01) to (H04). (H01) If the speed of the deformation of the working surface of the grindstone (abrasion speed) is known in advance, the machining of the grindstone is always good by performing electric discharge machining at a constant speed without detecting the shape of the working surface of the grindstone. It is possible to do. (H02) As a method of detecting the shape of the working surface of the grindstone while grinding the work, instead of employing the method of always detecting as described in the first embodiment, for example, the grindstone which is always expected to be a grindstone is used. It is possible to detect the shape of the working surface of the grindstone only when a portion where no electric discharge occurs locally occurs while performing electric discharge machining at a machining speed corresponding to the wear speed of the grinding wheel. (H03) Further, as a method of detecting the shape of the working surface of the grinding stone, a method using an electric micrometer (contact type), a method using a capacitance type small displacement meter (non-contact type), a diffuse reflection type optical displacement It is possible to adopt a method using a meter (non-contact type) or the like. (H04) Instead of using a so-called micro-discharge power supply of the accumulator type, a normal electric discharge power supply can be used as the electric discharge power supply 21.

[0032]

The above-described grinding apparatus of the present invention can provide the following effect (E01). (E01) When a workpiece is ground by a grindstone, highly accurate grinding can be performed without interrupting the grinding.

[Brief description of the drawings]

FIG. 1 is an overall explanatory view of Embodiment 1 of a grinding apparatus according to the present invention.

FIG. 2 is a diagram showing a grindstone forming apparatus according to the first embodiment, and is an enlarged view of a main part of FIG. 1;

FIG. 3 is an enlarged view of a state in which a grindstone is subjected to electric discharge machining by a grindstone forming apparatus.

FIG. 4 is an explanatory diagram of a method for measuring the shape of a grindstone.

FIG. 5 is a flowchart showing a grindstone forming flow performed before starting work of a workpiece.

FIG. 6 is a flowchart showing a flow at the time of processing a workpiece.

FIG. 7 is an explanatory view of a grinding apparatus according to a second embodiment of the present invention.

[Explanation of symbols]

W: Workpiece, 2: Grinding stone, 3: Grinding stone forming device support member, 4
... Whetstone forming device, 6 ... Two-axis table, 12 ... Wire guide, 13 ... Wire electrode,

──────────────────────────────────────────────────続 き Continued on front page (58) Field surveyed (Int.Cl. ⁷ , DB name) B24B 53/00 B24B 49/18

Claims (3)

(57) [Claims] 1. A grinding machine characterized by the following requirements (Y01) to (Y04): (Y01) a grindstone for grinding a work is rotatably supported, and a grindstone is supported relative to the work. (Y02) a work processing control device for controlling the relative movement of the work and the grindstone to grind the work with the grindstone; and (Y03) a predetermined grinding device for the grindstone support member. (Y04) a two-axis table supported by the grindstone forming device support member and movable in the width direction of the working surface of the whetstone and in a direction perpendicular to the working surface; A wire guide supported by a biaxial table, a wire running device for running a wire electrode for electric discharge machining along a guide groove formed on the outer periphery of the wire guide, Whetstone forming means for simultaneously forming a whetstone according to the shape of the working surface of the whetstone by electric discharge machining between the whetstone and the wire electrode, and a whetstone forming apparatus for forming the shape of the whetstone by electric discharge machining . 2. The grinding apparatus according to claim 1, wherein the grinding wheel has the following requirement (Y05): (Y05) the grinding wheel having a working surface shape detecting means for detecting a shape of a working surface of the grinding wheel. Molding means. 3. The grinding apparatus according to claim 2, wherein the following requirements (Y06) are satisfied: (Y06) the wire electrode is positioned at a plurality of positions in a direction transverse to a moving direction of the working surface of the whetstone. The working surface shape detecting means for detecting the shape of the working surface of the grinding wheel by detecting a discharge start position.