JP4088061B2 - Vibration cutting method and vibration cutting apparatus - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a vibration cutting method and a vibration cutting device that perform cutting while vibrating a tool relative to a work material.
[0002]
[Prior art]
2. Description of the Related Art Conventionally, a vibration cutting method that applies linear vibration to a tool in a cutting edge direction (a direction along the cutting edge of the tool) has been put to practical use as a technique for reducing the processing force in cutting. In this linear vibration cutting method, cutting resistance is reduced by cutting while pulling or pushing the cutting edge of the tool.
[0003]
[Problems to be solved by the invention]
However, in the conventional linear vibration cutting method, since the cutting edge of the tool is always in contact with the work material, heat generated by friction increases. Therefore, wear of the cutting edge and alteration of the work material will be caused. In addition, since simple vibration in one direction is performed, the vibration speed becomes zero at the top dead center and the bottom dead center of the blade edge vibration, and the effect of cutting while pulling is lost. For this reason, there is a limit to the extent that cutting resistance can be reduced.
[0004]
Therefore, as a vibration cutting method for solving the above-described problem, there is a method disclosed in Japanese Patent Application No. 2001-097799 by the inventors of the present application. In the vibration cutting method described in the application, elliptical vibration cutting is performed in a plane including the cutting edge direction.
[0005]
In this elliptical vibration cutting, intermittent cutting is performed, so there is time to cool the tool edge away from the work material, and the cutting oil is supplied to the cutting point to reduce the temperature rise of the tool. Can do. Moreover, since cutting can be performed while always pulling, cutting resistance can also be reduced.
[0006]
However, since the above elliptical vibration cutting always performs cutting in the same direction, the cutting force in the cutting edge direction cannot be offset. For this reason, the average value of the component force in the blade edge direction cannot be apparently made zero, resulting in a problem that cutting resistance in the blade edge direction appears.
[0007]
The present invention has been made to solve the above-described problems. The object of the present invention is to suppress wear of the tool edge and deterioration of the work material, to reduce the cutting resistance, and to make the cutting force in the cutting edge direction apparently zero, thereby reducing the cutting resistance in the cutting edge direction. An object of the present invention is to provide a vibration cutting method and a vibration cutting apparatus that can avoid the occurrence of the above.
[0008]
[Means for Solving the Problems]
The vibration cutting method according to the present invention performs cutting in the cutting direction while relatively vibrating the tool with respect to the work material, and is a direction perpendicular to the cutting direction and along the cutting edge of the tool The cutting edge of the tool is reciprocated relative to the work material in the direction of the cutting edge to perform cutting in both the reciprocating directions, and at least at the point where the vibration speed of the cutting edge in the cutting edge direction becomes zero after the cutting. The intermittent cutting is performed by separating the blade from the cutting point. Here, in this specification, “cutting” is defined to include not only the case of cutting a workpiece represented by metal but also the case of cutting an object other than metal. The cutting edge direction refers to the direction along the cutting edge of the tool (it only needs to include a vibration component in the direction along the cutting edge), and the cutting direction refers to cutting or removing the work material. This is the direction in which the tool or work material is fed, and it is the direction averaged over time rather than the instantaneous direction including the vibration component.
[0009]
Thus, by cutting the cutting edge away from the cutting point at the point where the vibration speed in the cutting edge direction of the tool becomes zero after cutting, intermittent cutting can be performed and heat generation due to friction can be reduced. Further, by cutting the tool cutting edge relatively back and forth with respect to the work material in the direction of the cutting edge of the tool and performing cutting in both the reciprocating directions, the cutting can be performed while always pulling or pushing. Furthermore, since the cutting edge is reciprocated and cutting is performed in both directions, the cutting force in the direction of the blade edge can be offset between cutting while pulling and cutting while pushing. Thereby, the cutting edge direction component force can be apparently made zero.
[0010]
The relative movement compliance value between the between the workpiece tool Ru is relatively vibrating with respect to the workpiece the tool at frequencies of less than the compliance value for the static load. Thereby, the amount of deformation of a machine system such as a work material and a tool at the time of cutting can be reduced, and the influence of cutting resistance can be substantially reduced.
[0011]
In addition, by moving the cutting edge in the direction of the back component force after the cutting, the cutting edge is moved away from the cutting point at the point where the vibration speed of the cutting edge in the cutting edge direction becomes zero, and the finishing after the cutting in the work material is performed. It may be separated from the surface. In this case, the cutting edge can be separated from the finished surface after cutting, and chipping of the cutting edge can be effectively suppressed.
[0012]
The vibration cutting device according to the present invention is configured to vibrate the tool relative to the work material at a frequency at which the relative dynamic compliance value between the work material and the tool is lower than the compliance value with respect to the static load. A first actuator for cutting the tool in a direction of the cutting edge, which is a direction along the cutting edge of the tool relative to the work material, and the cutting edge of the tool relative to the work material A second actuator that vibrates in a cutting direction that is perpendicular to the direction, and the cutting edge of the tool reciprocally moves in the direction of the blade edge relative to the work material to perform cutting in both directions, and at least the cutting edge after cutting And a controller for performing intermittent cutting by controlling the operations of the first and second actuators so that the cutting edge is separated from the cutting point at a point where the vibration speed of the cutting edge in the direction becomes zero.
[0013]
As described above, the vibration cutting device of the present invention includes the first and second actuators and the control unit, so that the cutting blade is reciprocated in the direction of the blade edge relative to the work material, and cutting is performed in both directions. In addition, the cutting edge can be separated from the cutting point at a point where the vibration velocity in the cutting edge direction of the cutting edge becomes zero after cutting. That is, the vibration cutting method of the present invention described above can be implemented.
[0014]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, embodiments of the present invention will be described with reference to FIGS. FIG. 1 is a schematic view for explaining the principle of the vibration cutting method of the present invention.
[0015]
As shown in FIG. 1, a work piece is cut while a blade portion having a cutting edge 3 of a vibration cutting tool 1 is vibrated by a vibrator 4 according to a desired locus. More specifically, the cutting edge 3 and the cutting (cutting) direction 7 are superimposed and applied to the blade portion, and the cutting edge 3 is moved back and forth in the cutting edge direction 6 of the vibration cutting tool 1 to perform cutting in both directions. In addition, the cutting edge 3 is separated from the cutting point at a point where the vibration speed in the cutting edge direction 6 of the vibration cutting tool 1 becomes zero after cutting.
[0016]
By separating the cutting edge 3 from the cutting point at the point where the vibration speed becomes zero as described above, it is possible to cut while always pulling or pushing during cutting. Further, by performing intermittent cutting in this way, cutting oil is supplied to the cutting point, and the cutting force can be reduced by the cooling effect and the lubricating effect, and the temperature rise due to friction can be reduced, and the wear and wear of the tool edge can be reduced. Alteration of the cutting material 2 can be suppressed.
[0017]
In addition, by cutting the blade 3 in the reciprocating direction in the blade edge direction 6 of the vibration cutting tool 1 and performing the cutting in both the reciprocating directions, the cutting can be performed while always pulling or pushing. Thereby, cutting resistance can be reduced.
[0018]
Furthermore, since the cutting edge 3 is reciprocated and cutting is performed in both directions, the cutting force in the cutting edge direction 6 can be offset between the case of cutting while pulling and the case of cutting while pushing. As a result, the component force in the cutting edge direction can be apparently zero, and the occurrence of cutting resistance in the cutting edge direction 6 can also be avoided.
[0019]
In the above example, the blade portion of the vibration cutting tool 1 is vibrated. However, as long as the blade portion of the vibration cutting tool 1 can be vibrated relative to the work material 2 according to a desired locus. The work material 2 side may be vibrated.
[0020]
Next, an example of a specific vibration locus of the cutting edge (tool edge) 3 of the vibration cutting tool 1 according to the present invention will be described.
[0021]
In the example shown in FIG. 1, cutting is performed while the cutting edge 3 is driven according to an ∞-shaped locus. That is, after cutting in the left direction in FIG. 1, the blade portion is moved upward away from the work material 2 (cutting point), and the cutting edge 3 is cut at the first point 16 where the vibration speed in the blade edge direction 6 becomes zero. 1 is moved away from the work material 2, and then the cutting is performed in the right direction in FIG. 1 while moving the blade portion downward again toward the work material 2. After the cutting, the blade portion is again cut into the work material 2 ( The cutting edge 3 is moved away from the cutting point), and the cutting edge 3 is moved away from the workpiece 2 at the second point 17 where the vibration speed in the cutting edge direction 6 becomes zero. By performing cutting while driving the cutting edge 3 according to such a trajectory, the above-described effects can be obtained.
[0022]
2A to 2C show other examples of the locus of the cutting edge (tool edge) 3. FIG. As shown in FIG. 2A, the cutting edge 3 may be reciprocated along a parabolic trajectory. In this case, cutting is performed while alternately moving the cutting edges 3 in the left-right direction, which is the cutting edge direction 6 in FIG. 2A, and the first and first vibration speeds in the cutting edge direction 6 and the cutting direction 7 become zero after cutting. The cutting edge 3 is separated from the work material 2 (cutting point) at two points (top dead center and bottom dead center) 16 and 17.
[0023]
Further, as shown in FIGS. 2B and 2C, the cutting edge 3 may be reciprocated along a locus having a complicated shape. In any case, the cutting edge 3 is reciprocated in the cutting edge direction 6 of the vibration cutting tool 1 to perform cutting in both the reciprocating directions, and the vibration speed in the cutting edge direction 6 of the vibration cutting tool 1 becomes zero after cutting. Then, the cutting edge 3 can be separated from the work material 2 (cutting point) at the second points 16 and 17.
[0024]
The trajectory of the ∞ shape or parabolic shape can be obtained by doubling the vibration frequency in the cutting direction 7 to the vibration frequency in the cutting edge direction 6 and setting the initial phase difference to 0 and π / 2, respectively. The trajectory shown in FIG. 2B is obtained by setting the vibration frequency in the cutting direction 7 to 2/3 times the vibration frequency in the cutting edge direction 6 and setting the phase difference to zero. The trajectory shown in FIG. Is obtained by setting the vibration frequency in the cutting direction 7 to four times the vibration frequency in the cutting edge direction 6 and making the phase difference zero.
[0025]
Next, the structural example of the vibration cutting apparatus which can implement the vibration cutting method of this invention mentioned above is demonstrated using FIGS. In the following example, a case will be described in which the cutting edge of the tool is vibrated according to a parabolic trajectory.
[0026]
In the example shown in FIG. 3, the vibration cutting device includes a vibration cutting tool 1 such as a cutter or a knife, a flexural vibration exciting piezoelectric element 10 and a longitudinal vibration exciting piezoelectric element 11 that function as an actuator, and a control unit 12. .
[0027]
The vibration cutting tool 1 includes a blade portion having a cutting edge 3, a support tool 8 that supports a tool body via a support point 9, a flexural vibration excitation piezoelectric element 10 and a longitudinal vibration excitation piezoelectric element that are attached to the tool body. Element 11.
[0028]
The piezoelectric element 10 for flexural vibration excitation is composed of a set of piezoelectric elements, and is installed in the vicinity of the antinode of the flexural vibration where the maximum flexure is obtained. The longitudinal vibration exciting piezoelectric element 11 is also composed of a set of piezoelectric elements, and is installed near the position of the longitudinal vibration node where the longitudinal strain is maximized.
[0029]
The reason why the piezoelectric elements are used in pairs is to insert an electrode between them, and the other electrode is the vibrator itself. The vibrator is fixed locally at a position where the vibrations in both directions become nodes so that the vibrations are not hindered. In the present embodiment, a secondary resonance mode of longitudinal vibration and a fifth resonance mode of flexural vibration are used.
[0030]
When matching these vibrations, adjusting the diameter of the vibrator makes it possible to change only the frequency of the flexural vibration with little effect on the resonant frequency of the longitudinal vibration. Can be matched.
[0031]
The control unit 12 is connected to the flexural vibration exciting piezoelectric element 10 and the longitudinal vibration exciting piezoelectric element 11 and controls their operations. For example, a sine wave voltage having a frequency of about several Hz to several tens of kHz is applied from the control unit 12 to the longitudinal vibration exciting piezoelectric element 11 and a cosine wave voltage having a frequency twice that of the piezoelectric vibration exciting piezoelectric element 10 is applied. To do. However, since the phase difference between the applied voltage and the vibration displacement changes abruptly in the vicinity of the resonance frequency, the phase difference between the two voltages is actually set so that the phase difference between the displacements in the two directions becomes a desired value. Correct.
[0032]
3 can be simultaneously applied to the vibration cutting tool 1 as shown in FIG. 3, and the cutting edge 3 can be driven along a parabolic locus by superimposing these vibrations. In this way, the object such as paper, food, plastic, and each part of the human body is cut while driving the cutting edge 3.
[0033]
4A and 4B, the vibration cutting apparatus includes a vibration cutting tool 1 that performs turning and engraving, a torsional vibration excitation piezoelectric element 13 and a longitudinal vibration excitation piezoelectric element 11 that function as actuators. And a control unit 12.
[0034]
The vibration cutting tool 1 has an arcuate cutting edge 3. The radius of the arc is preferably equal to or larger than the radius of the arc (torsional vibration component) when the blade edge vibration is viewed from the axial direction of the vibration cutting tool 1. Note that the cutting edge and the vibration trajectory do not necessarily have an arc shape. In the case where the cutting edge is not a circular arc, the cutting edge curvature of the vibration cutting tool 1 should always be greater than or equal to the curvature of vibration. This is to prevent the flank face of the blade edge from being pressed against the finished surface by vibration.
[0035]
The torsional vibration exciting piezoelectric element 13 is composed of a set of piezoelectric elements, and is installed in the vicinity of the position of the torsional vibration node where the strain due to torsion is maximized. The longitudinal vibration exciting piezoelectric element 11 is also composed of a set of piezoelectric elements, and is installed near the position of the longitudinal vibration node where the longitudinal strain is maximized.
[0036]
In the case of this example, a sine wave voltage having a frequency of about several Hz to several tens of kHz is applied to the torsional vibration exciting piezoelectric element 13, and a cosine wave voltage having a frequency twice that of the longitudinal vibration exciting piezoelectric element 11 is applied. .
[0037]
Thereby, the torsional vibration and the longitudinal vibration as shown in FIG. 4 can be simultaneously applied to the vibration cutting tool 1, and by superposing these, the cutting edge 3 has a parabolic trajectory (more precisely, a trajectory in a cylindrical plane). Can be driven along. In this way, turning or engraving of an object such as a metal material is performed while driving the cutting edge 3.
[0038]
In the example shown in FIGS. 5A and 5B, the vibration cutting apparatus includes a vibration cutting tool 1 that cuts an object, a left and right vibration excitation piezoelectric element 14 that functions as an actuator, and a vertical vibration excitation piezoelectric element 15. And a control unit 12.
[0039]
The left and right vibration excitation piezoelectric element 14 and the vertical vibration excitation piezoelectric element 15 are installed so as to be in a positional relationship orthogonal to both corner portions of the vibration cutting tool 1. Then, a sine wave voltage having a frequency of about several Hz to several tens of kHz is applied to the left and right vibration excitation piezoelectric element 14, and a cosine wave voltage having a frequency twice that of the vertical vibration excitation piezoelectric element 15 is applied.
[0040]
Thereby, the cutting edge 3 can be driven along a parabolic trajectory as shown in FIG. 5, and the object can be cut.
[0041]
In the above-described example, a piezoelectric element is used as an example of the actuator. However, any actuator other than the piezoelectric element can be used as long as it can apply two types of vibrations to the tool. Moreover, the cutting blade 3 can be driven along a locus other than a parabola by appropriately adjusting the frequency and phase difference of the voltage applied to each piezoelectric element.
[0042]
Furthermore, the present invention is not limited to the above-described applications, and can be applied to various vibration cutting tools. For example, the present invention can also be applied to ultra-precision fine processing using a diamond tool or the like.
[0043]
Next, the vibration frequency given to the tool in consideration of deformation of the work material will be described with reference to FIG. FIG. 6 is a diagram illustrating a measurement example of the dynamic compliance (displacement / excitation force transfer function) on the machine tool spindle side.
[0044]
As shown in FIG. 6, it is found that the deformation is about 0.05 μm / N statically and about 1 μm / N at resonance of about 500 Hz, but hardly deforms in the high frequency region of 3 kHz or higher.
[0045]
From this, it is possible to perform cutting while reducing the amount of deformation of the work material, tool, and processing machine by performing cutting while vibrating the tool at high frequency. That is, cutting is performed while the tool is vibrated relative to the work material at a frequency (high frequency) at which the relative dynamic compliance value between the work material and the tool is lower than the compliance value with respect to the static load. Accordingly, it is possible to perform cutting while keeping the deformation amount of the work material, tool, and processing machine low. As a result, processing accuracy and finished surface properties can be improved.
[0046]
Next, an extended example of the vibration cutting method of the present invention will be described with reference to FIGS. 7 and 8 are diagrams showing the blade tip vibration locus in this extended example.
[0047]
As shown in FIG. 7, the surface of the parabolic vibration may be rotated around the cutting edge of the tool so that the cutting edge is separated from the finished surface when the cutting edge is separated from the chips. By thus separating the cutting edge from the chips and the finished surface, it is possible to suppress chipping of the cutting edge.
[0048]
In order to drive the tool so that the blade edge vibration locus shown in FIG. 7 is obtained, for example, the above-described vibration device itself may be slightly rotated around the blade edge direction.
[0049]
FIG. 9 shows an example of vibration cutting to which this extended example can be applied. By attaching the piezoelectric elements described above to the vibration cutting tool 1 shown in this figure and applying the voltages described above, the vibration cutting tool 1 can be driven according to the blade tip vibration locus shown in FIGS. The work material 2 can be cut.
[0050]
Also, as shown in FIG. 8, the parabolic vibration cutting of the present invention may be combined with other types of vibration cutting such as elliptical vibration cutting. In this case, vibration cutting having the advantages of both methods can be performed. The technique of this example can also be applied to the vibration cutting shown in FIG.
[0051]
In order to drive the tool so that the cutting edge vibration locus shown in FIG. 8 is obtained, for example, a cutting direction vibration piezoelectric element, a cutting edge direction vibration piezoelectric element and a back component force direction vibration piezoelectric element are attached to the tool, and the cutting direction vibration piezoelectric element is attached to the tool. Apply a cosine wave voltage, apply a cosine wave voltage of 1/2 frequency in the cutting direction to the piezoelectric element for vibration in the cutting edge direction, and apply a sine wave voltage of the same frequency in the cutting direction to the piezoelectric element for vibration in the back force direction. That's fine.
[0052]
Although the embodiment of the present invention has been described above, the present invention is not limited to the above embodiment. The scope of the present invention is defined by the terms of the claims, and includes meanings equivalent to the terms of the claims and all modifications within the scope.
[0053]
【The invention's effect】
According to the present invention, temperature rise due to shearing and friction during cutting can be reduced, cutting resistance can be reduced by cutting while always pulling or pushing, and the average value of the component force in the blade edge direction Since the appearance can be made to be zero, it is possible to suppress the wear of the tool edge, the deterioration of the work material, the deformation of each part that deteriorates the machining accuracy, and avoid the occurrence of cutting resistance in the direction of the edge. be able to.
[Brief description of the drawings]
FIG. 1 is a schematic diagram for explaining the principle of a vibration cutting method of the present invention.
FIGS. 2A to 2C are diagrams showing examples of trajectories of the tool cutting edge of the present invention.
FIG. 3 is a schematic configuration diagram of a vibration cutting apparatus of the present invention.
4A is a side view of a vibration cutting tool in another example of the present invention, and FIG. 4B is a schematic configuration diagram of a vibration cutting apparatus in another example of the present invention.
5A is a cross-sectional view taken along line AA of the vibration cutting tool shown in FIG. 5B, and FIG. 5B is a schematic configuration diagram of a vibration cutting apparatus in still another example of the present invention.
FIG. 6 is a diagram showing a measurement example of dynamic compliance (displacement / excitation force transfer function) on the machine tool spindle side;
FIG. 7 is a diagram showing a blade edge vibration locus in one extension example of the vibration cutting method of the present invention.
FIG. 8 is a diagram showing a blade edge vibration locus in another example of expansion of the vibration cutting method of the present invention.
FIG. 9 is a perspective view showing an example of vibration cutting to which the method shown in FIGS. 7 and 8 can be applied.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 Vibration cutting tool, 2 Work material, 3 Cutting blade, 4 Vibrator, 5 Vibration locus, 6 Cutting edge direction, 7 Cutting direction, 8 Support tool, 9 Supporting point, 10 Piezoelectric element for bending vibration excitation, 11 Longitudinal vibration excitation Piezoelectric element, 12 control unit, 13 piezoelectric element for torsional vibration excitation, 14 piezoelectric element for left-right vibration excitation, 15 piezoelectric element for vertical vibration excitation, 16 first point, 17 second point.

Claims (3)

Vibrations performing relative movement compliance value is the cutting in the cutting direction while relatively vibrating the tool at frequencies of less than the compliance value for the workpiece with respect to a static load of between workpiece and tool A cutting method,
The cutting edge of the tool is reciprocated with respect to the work material in a direction perpendicular to the cutting direction and along the cutting edge of the tool to perform cutting in both reciprocating directions, and at least the cutting A vibration cutting method comprising performing intermittent cutting by separating the cutting edge from a cutting point at a point where the vibration speed of the cutting edge in the direction of the cutting edge becomes zero later. The cutting edge is moved away from the cutting point at the point where the vibration speed of the cutting edge in the cutting edge direction becomes zero by moving the cutting edge also in the direction of the back component force after the cutting, and the cutting in the work material The vibration cutting method according to claim 1, wherein the vibration cutting method is separated from a later finished surface. Vibration cutting device for performing cutting while relatively oscillating the tool relative to the workpiece at a frequency relative movement compliance value between the work material and the tool is lower than the compliance value for static load There,
A first actuator that vibrates the tool in a cutting edge direction that is a direction along the cutting edge of the tool relative to the work material;
A second actuator for causing the tool to vibrate in a cutting direction which is a direction perpendicular to the cutting edge direction relative to the work material;
The cutting edge of the tool is reciprocated relative to the work material in the direction of the cutting edge to perform cutting in both directions, and at least after the cutting, the vibration speed of the cutting edge in the cutting edge direction becomes zero. A control unit for performing intermittent cutting by controlling the operations of the first and second actuators so that the cutting edge is separated from the cutting point at a point;
A vibration cutting device comprising:

Images