JP2007075915A - Cutting method and cutting apparatus - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a cutting method capable of greatly improving the degree of freedom of the surface shape of a workable work material and capable of forming a sharp edge shape.
A cutting tool 3 supported so as to be displaceable in three different directions is controlled so as to be independently displaced in three directions in accordance with the relative movement of the cutting tool 3 with respect to a work material 2.
[Selection] Figure 1

Description

  The present invention relates to a cutting method and a cutting apparatus that perform cutting while synchronizing with the rotation of a base spindle that holds a work material and displacing a cutting tool at a higher speed with respect to the work material.

  2. Description of the Related Art Conventionally, a cutting apparatus that performs cutting while further displacing a cutting tool that moves relative to a work material with respect to the work material is known (see, for example, Non-Patent Document 1). Non-Patent Document 1 discloses a cutting device for controlling a cutting amount by a cutting tool at a high speed in synchronization with rotation of a main spindle of a lathe to which a work material is attached, and creating a predetermined surface shape. ing. In this cutting apparatus, the cutting tool is driven and displaced by a driving means using a piezoelectric element, and the cutting amount by the cutting tool is controlled.

Yuichi Okazaki, “Creation of fine surface shape by diamond cutting”, Vacuum, Vol. 40, No. 6, 1997

  However, in the cutting apparatus described in Patent Document 1, cutting is performed by displacing the cutting tool in synchronization with the rotation of the main spindle of the lathe, but the cutting tool is displaced only in one axial direction by a driving means using a piezoelectric element. By doing so, the amount of cut is controlled. For this reason, the surface shape of the workable material is limited to the shape obtained by the combination of the rotational motion of the work material and the displacement of the cutting tool in one axis direction, and the degree of freedom of the workable shape is limited. There is a problem of being constrained. In particular, in the case of a combination of the rotational motion of the work material and the displacement in one axial direction of the cutting tool, it is inherently difficult to form a sharp edge shape on the surface of the work material. Is desired, it is necessary to form an approximate shape by greatly reducing the relative speed between the work material and the cutting tool, which tends to cause a reduction in productivity and sufficient dimensional accuracy. It will also be difficult to ensure.

  In view of the above circumstances, the present invention relates to a cutting method and a cutting apparatus that perform cutting while further displacing a cutting tool that moves relative to a work material with respect to the work material. It is an object of the present invention to greatly improve the degree of freedom of the surface shape of the cutting material and to enable the formation of a sharp edge shape.

Means and effects for solving the problems

In order to achieve the above object, the cutting method according to the present invention performs cutting while synchronizing the rotation of the base spindle holding the work material and displacing the cutting tool at a higher speed with respect to the work material. The present invention relates to a cutting method.
And this invention has the following some features for achieving the said objective. In other words, the present invention includes the following features alone or in combination as appropriate.

  The first feature of the cutting method according to the present invention for achieving the above object is that the cutting tool supported so as to be displaceable in three different directions is moved relative to the work material. Accordingly, a three-way independent control step for controlling to be displaced independently in the three directions is provided.

  According to this configuration, the surface shape of the work material is cut by moving the cutting tool independently in three directions at a higher speed with respect to the work material while synchronizing with the rotation of the base spindle holding the work material. be able to. For this reason, it is possible to move the cutting tool in an arbitrary direction with respect to the work material in a three-dimensional space, thereby transferring an arbitrary three-dimensional shape to the surface of the work material. Is possible. In addition, by appropriately combining the displacements of the cutting tool in the three directions, a sharp edge shape can be formed while synchronizing with the rotation of the lathe spindle. Even if such a sharp edge shape is formed, it is possible to suppress a reduction in productivity, and it is possible to easily ensure sufficient dimensional accuracy. Therefore, according to the cutting method of the present invention, the degree of freedom of the surface shape of the workable material can be greatly improved, and a sharp edge shape can be formed.

  The second feature of the cutting method according to the present invention is that in the three-way independent control step, feedback control is performed by measuring a displacement amount of the cutting tool in each of the three directions.

  According to this configuration, by performing feedback control of the displacement amount in each of the three directions of the cutting tool, the followability of the cutting tool displacement to the target can be improved, and more accurate cutting can be realized. It is possible to correct a deviation from a target displacement that occurs due to the mutual displacements affecting each other.

  A third feature of the cutting method according to the present invention is that the three directions are orthogonal to each other.

  According to this configuration, since the displacement of the cutting tool is controlled in three orthogonal directions, the cutting tool can be easily positioned in a three-dimensional space on the basis of the orthogonal coordinate system, and the three influence each other. Complicating the relationship of displacement in two directions can be suppressed and the correction can be easily performed.

In order to achieve the above object, a cutting device according to the present invention performs cutting while synchronizing the rotation of a base spindle holding a work material and displacing a cutting tool at a higher speed with respect to the work material. The present invention relates to a cutting apparatus.
And this invention has the following some features for achieving the said objective. In other words, the present invention includes the following features alone or in combination as appropriate.

  The first feature of the cutting apparatus according to the present invention for achieving the above object is that a base portion that supports the cutting tool, and a first direction, a second direction, and a third direction that are different from each other in the base portion. A first driving means for displacing in the first direction, a second driving means for displacing in the second direction, and a third driving direction in the third direction. A third driving means for displacing the first driving means, and the first driving means for displacing the base portion independently in the first direction, the second direction, and the third direction, respectively. And a control means for controlling the second drive means and the third drive means.

  According to this configuration, the surface of the work material is obtained by independently displacing the cutting tool in the first to third directions at a higher speed with respect to the work material while synchronizing with the rotation of the base spindle holding the work material. The shape can be cut. For this reason, it is possible to move the cutting tool in an arbitrary direction with respect to the work material in a three-dimensional space, thereby transferring an arbitrary three-dimensional shape to the surface of the work material. Is possible. In addition, by appropriately combining the displacements of the cutting tool in the three directions, a sharp edge shape can be formed while synchronizing with the rotation of the lathe spindle. Even if such a sharp edge shape is formed, it is possible to suppress a reduction in productivity, and it is possible to easily ensure sufficient dimensional accuracy. Therefore, according to the cutting apparatus of the present invention, the degree of freedom of the surface shape of the workable material can be greatly improved, and a sharp edge shape can be formed.

  The second feature of the cutting apparatus according to the present invention further comprises a displacement sensor that detects a displacement amount of the base portion in each of the first direction, the second direction, and the third direction, The control means performs feedback control of the displacement of the base portion based on the result detected by the displacement sensor.

  According to this configuration, by performing feedback control on the amount of displacement of each of the first to third directions of the cutting tool, it is possible to improve the followability of the cutting tool to the target and realize higher-precision cutting. The deviation with respect to the target displacement that occurs when the displacements in the first to third directions influence each other can be corrected.

  A third feature of the cutting apparatus according to the present invention is that the first direction, the second direction, and the third direction are orthogonal to each other.

  According to this configuration, since the displacement of the cutting tool is controlled in the first to third directions orthogonal to each other, the cutting tool can be easily positioned in the three-dimensional space based on the orthogonal coordinate system, and Complicating the displacement relationship in the first to third directions that affect each other can be suppressed, and the correction can be easily performed.

  A fourth feature of the cutting apparatus according to the present invention is that the first drive means, the second drive means, and the third drive means are formed using piezoelectric elements.

  According to this configuration, by forming the first to third driving means using piezoelectric elements, it is possible to easily realize a driving mechanism that can perform minute displacement control in the first to third directions at high speed. be able to.

  DESCRIPTION OF EMBODIMENTS Embodiments for carrying out the present invention will be described with reference to the drawings. In addition, the cutting device and the cutting method according to the embodiment of the present invention are such that a cutting tool that moves relative to the work material is further displaced with respect to the cutting tool, such as FTS (Fast Tool Servo). The present invention can be widely applied when cutting.

  FIG. 1 is a schematic diagram showing a cutting apparatus 1 according to an embodiment of the present invention. The cutting apparatus 1 shown in FIG. 1 is provided for a lathe (not shown) for ultra-precision machining, and a cutting tool 3 that moves relative to the work material 2 is applied to the work material 2. The cutting is performed while further displacing. The work material 2 is attached to, for example, a main shaft of a lathe, and is disposed so as to rotate in a direction indicated by an arrow B in the drawing along with the rotation of the main shaft. And the housing 10 in the cutting apparatus 1 is arrange | positioned so that it may move to the 1-axis direction shown by arrow A in the figure with respect to the main axis | shaft of the lathe.

  FIG. 2 shows a control block diagram of the cutting apparatus 1 of the present embodiment. As shown in FIGS. 1 and 2, the cutting apparatus 1 according to the present embodiment includes an attachment block 4, a drive mechanism 5, a displacement sensor 9, a controller 9, a housing 10, and the like.

  As shown in FIG. 1, the attachment block 4 is a base portion that supports the cutting tool 3, and is attached to the housing 10 via the drive mechanism 5. The drive mechanism 5 is configured to drive the mounting block 4 so as to be displaced in three different directions, ie, a first direction, a second direction, and a third direction. In the present embodiment, the first to third directions are the X-axis direction (first direction), the Y-axis direction (second direction), and the Z-axis direction (third direction) that are orthogonal to each other. Is set as

  The drive mechanism 5 includes a first actuator 6, a second actuator 7, and a third actuator 8. The first actuator 6 is configured as first driving means for displacing the mounting block 4 in the X-axis direction with respect to the housing 10. The second actuator 7 serves as second driving means for displacing the mounting block 4 with respect to the housing 10 in the Y-axis direction, and the third actuator 8 is configured to displace the mounting block 4 with respect to the housing 10 in the Z-axis direction. It is comprised as a drive means. The first actuator 6, the second actuator 7, and the third actuator 8 are all configured using piezoelectric elements.

  As shown in FIG. 1, the displacement sensor 9 includes an X-axis displacement sensor 9a that detects the amount of displacement of the mounting block 4 in the X-axis direction, and a Y-axis displacement sensor 9b that detects the amount of displacement of the mounting block 4 in the Y-axis direction. And a Z-axis displacement sensor 9c that detects the amount of displacement of the mounting block 4 in the Z-axis direction. These axial displacement sensors 9 a, 9 b, 9 c are configured as capacitance sensors attached to the housing 10. Then, by measuring the distances to the measured pieces 17a, 17b, and 17c respectively attached to the attachment block 4, the displacement amount of the attachment block 4 with respect to the housing 10 in each axial direction, that is, each axis of the cutting tool 3 is measured. The displacement in the direction is measured.

  The controller 11 includes a CPU (Central Processing Unit), a memory (ROM (Read Only Memory), a RAM (Random Access Memory)), a current control circuit, and the like (not shown). The controller 11 controls the first actuator 9a, the second actuator 9b, and the third actuator 9c so as to displace the mounting block 4 independently in the X-axis direction, the Y-axis direction, and the Z-axis direction. It is configured as a control means.

  Further, as shown in the control block diagram of FIG. 2, the controller 11 is configured to perform feedback control of the displacement of the mounting block 4 based on the result detected by the displacement sensor 9 (9a, 9b, 9c). ing. First, as coordinate signals from a stage encoder (not shown) of a lathe for ultraprecision machining, the position coordinates of the cutting tool 3 in the direction of arrow A in FIG. To the controller 11. A real-time target value calculation unit 12 is constructed in the controller 11, and each axis (X axis, X) of the cutting tool 3 (that is, the mounting block 4) is determined based on a predetermined calculation formula in accordance with the read coordinates. A target position (target displacement) in the Y-axis and Z-axis directions is calculated. The driving of the first actuator 9a, the second actuator 9b, and the third actuator 9c is controlled so that the displacement of the mounting block 4 follows the target position for each axis. That is, the X-axis target position is determined based on the detection result of the displacement sensor 9a by the X-axis feedback control system including the PID controller 13a, the D / A converter 14a, the amplifier 16a, and the A / D converter 15a. The first actuator 9a is driven so that the displacement of the mounting block 4 follows. The Y-axis target position is determined based on the detection result of the displacement sensor 9b by the Y-axis feedback control system including the PID controller 13b, the D / A converter 14b, the amplifier 16b, and the A / D converter 15b. The second actuator 9b is driven so that the displacement of the mounting block 4 follows. Further, the Z-axis target position is determined based on the detection result of the displacement sensor 9c by the Z-axis feedback control system including the PID controller 13c, the D / A converter 14c, the amplifier 16c, and the A / D converter 15c. The third actuator 9c is driven so that the displacement of the mounting block 4 follows.

  In addition, the cutting method of this embodiment is implement | achieved when the cutting apparatus 1 operate | moves. That is, the cutting method according to the present embodiment applies the cutting tool 3 supported so as to be displaceable in three directions (X-axis direction, Y-axis direction, and Z-axis direction) orthogonal to each other to the work material 2. According to the relative movement of the cutting tool 3, it is configured to include a three-way independent control step for controlling the displacement independently in the three directions of the X, Y, and Z axes. In the three-way independent control step, as described above, the displacement amount of each of the three cutting tools 3 in the X, Y, and Z-axis directions is measured by the displacement sensor 9 and feedback control is performed by the controller 11. .

  Here, the result of evaluating the response characteristics in order to confirm the control performance in the cutting apparatus 1 of the present embodiment will be described. 3 and 4 show the results of the step response operation evaluation when the control is performed by giving a command of 0.25 μm step feed in the Z-axis direction, and FIG. 3 shows the case where the open loop control is performed. FIG. 4 shows a case where feedback control is performed. In the open loop control shown in FIG. 3, the mounting block 4 is displaced in the X axis and Y axis directions along with the feed in the Z axis direction, and interference occurs. In the feedback control shown in FIG. It was confirmed that the occurrence of such interference could be corrected. FIG. 5 shows frequency response characteristics. As shown in FIG. 5, almost the same frequency characteristics are obtained in any of the X-axis direction, the Y-axis direction, and the Z-axis direction, and it is confirmed that a sufficient response is obtained up to about 600 to 800 Hz. did it.

  As described above, according to the cutting method and the cutting apparatus 1 of the present embodiment, the cutting tool 3 is moved at a higher speed relative to the work material 2 while being synchronized with the rotation of the base spindle that holds the work material 2. The surface shape of the work material 2 can be cut by being independently displaced in the first to third directions. For this reason, the cutting tool 3 can be moved in an arbitrary direction by an arbitrary distance with respect to the work material 2 in the three-dimensional space, whereby an arbitrary three-dimensional shape is formed on the surface of the work material 2. It becomes possible to transfer. Further, by appropriately combining the displacements of the cutting tool 3 in the three directions, a sharp edge shape can be formed while synchronizing with the rotation of the main spindle of the lathe. Even if such a sharp edge shape is formed, it is possible to suppress a reduction in productivity, and it is possible to easily ensure sufficient dimensional accuracy. Therefore, according to the cutting method and the cutting apparatus 1 of the present embodiment, the degree of freedom of the surface shape of the workable material can be greatly improved, and a sharp edge shape can be formed. it can.

  In addition, according to the cutting method and the cutting apparatus 1 of the present embodiment, feedback control of the displacement amounts of the cutting tool 3 in the first to third directions allows feedback of the displacement of the cutting tool 3 to the target. Thus, it is possible to realize cutting with higher accuracy, and it is possible to correct a deviation with respect to a target displacement generated by displacements in the first to third directions interacting with each other.

  Further, according to the cutting method and the cutting apparatus 1 of the present embodiment, in order to control the displacement of the cutting tool 3 in the first to third directions orthogonal to each other, the positioning of the cutting tool 3 in the three-dimensional space is orthogonal coordinate system. Further, it is possible to easily perform the correction based on the above, and it is possible to suppress the complicated relationship of the displacements in the directions of the first to the stage that influence each other and to easily correct the displacement.

  Further, according to the cutting apparatus 1, the first to third actuators (6, 7, 8) are formed using piezoelectric elements, so that the minute displacements can be controlled at high speeds in the first to third directions, respectively. It is possible to easily realize a drive mechanism that can be used.

  The embodiments of the present invention have been described above. However, the present invention is not limited to the above-described embodiments, and various modifications can be made as long as they are described in the claims. For example, in the present embodiment, the case where the first to third directions are orthogonal to each other has been described as an example, but this need not necessarily be the case, and an arbitrary coordinate system can be set. In the present embodiment, the first to third driving means are described by way of example using piezoelectric elements. However, this need not be the case, and a voice coil, hydraulic equipment, or the like may be used. It may be formed.

It is a mimetic diagram showing the cutting device concerning one embodiment of the present invention. It is a control block diagram in the cutting apparatus shown in FIG. The result of step response operation | movement evaluation at the time of performing open loop control in the cutting apparatus shown in FIG. 1 is shown. The result of step response operation | movement evaluation at the time of performing feedback control in the cutting apparatus shown in FIG. 1 is shown. The frequency response characteristic in the cutting apparatus shown in FIG. 1 is shown.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Cutting device 2 Work material 3 Cutting tool 4 Mounting block (base part)
5 drive mechanism 6 first actuator (first drive means)
7 Second actuator (second drive means)
8 Third actuator (third drive means)
9 Displacement sensor 11 Controller (control means)

Claims (7)

A cutting method that performs cutting while synchronizing the rotation of the base spindle that holds the work material and displacing the cutting tool at a higher speed with respect to the work material,
Three-way independent control for controlling the cutting tool supported so as to be displaceable in three different directions from each other independently in the three directions in accordance with the relative movement of the cutting tool with respect to the work material. A cutting method characterized by comprising a step.   2. The cutting method according to claim 1, wherein in the three-way independent control step, feedback control is performed by measuring a displacement amount of the cutting tool in each of the three directions.   The cutting method according to claim 1 or 2, wherein the three directions are orthogonal to each other. A cutting device that synchronizes with the rotation of the base spindle that holds the work material and performs cutting while further displacing the cutting tool with respect to the work material,
A base for supporting the cutting tool;
A driving mechanism for driving the base portion to displace in a first direction, a second direction, and a third direction different from each other, the first driving means for displacing the base portion in the first direction; A drive mechanism having second drive means for displacing in a second direction and third drive means for displacing in the third direction;
The first driving means, the second driving means, and the third driving means are configured to displace the base portion independently in the first direction, the second direction, and the third direction, respectively. Control means for controlling;
A cutting apparatus characterized by comprising: A displacement sensor for detecting a displacement amount of each of the base portion in the first direction, the second direction, and the third direction;
The cutting apparatus according to claim 4, wherein the control unit performs feedback control of displacement of the base portion based on a result detected by the displacement sensor.   The cutting apparatus according to claim 4 or 5, wherein the first direction, the second direction, and the third direction are orthogonal to each other.   The cutting according to any one of claims 4 to 6, wherein the first driving means, the second driving means, and the third driving means are formed using a piezoelectric element. Processing equipment.

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