JP6980536B2 - Cutting equipment and its control method - Google Patents

Description

The present invention relates to a cutting apparatus for cutting a work material by pressing the cutting edge of a tool against a work material rotating around an axis and a control method thereof.

The cutting edge of a tool that uses a machine tool such as an automatic lathe or machining center as a cutting device and feeds a work material (work) such as a round bar that is fixed and held by the spindle in the feed direction while rotating it around its axis. It is widely practiced in the parts manufacturing industry and the like to manufacture various products by cutting the work material by pressing the work material against the work material.

In cutting using such a cutting device, the work material is continuously cut by the tool, so that continuous long chips (chips) are generated, and the chips are entangled with the tool and the work material and are cut. Problems such as obstacles may occur.

As a cutting device that solves such a problem, a so-called vibration cutting device is conventionally known in which a tool is fed while vibrating (reciprocating) at a predetermined frequency along a feeding direction. (See, for example, Patent Document 1). According to the cutting apparatus having such a configuration, it is possible to generate a milling period in which the work material is not cut by the tool during cutting, so that the chips can be sequentially divided to improve the processability of the chips. ..

International Publication No. 2015/146945

However, in a configuration or method in which chips are sequentially divided by feeding the tool while vibrating it at a predetermined frequency along the feeding direction as in the above-mentioned conventional cutting device, the feeding speed of the tool increases or decreases. Since the cutting process is performed while the machine is being machined, the machining accuracy deteriorates due to unevenness in the grinding of the tool on the machined surface of the material to be machined, which deteriorates the surface roughness and roundness of the machined product. There was a problem that it would end up.

An object of the present invention is to solve such a problem, and an object of the present invention is to provide a cutting device capable of improving the processability of chips without lowering the processing accuracy and a control method thereof. There is something in it.

The cutting device of the present invention is a cutting device that presses the cutting edge of a tool against a work material that rotates around an axis to cut the work material, and is a spindle that rotates the work material around the axis line. A feeding means for feeding the tool in the feeding direction, and a swinging means for swinging the tool along a plane parallel to the feeding direction with the center of the arcuate nose of the cutting edge as a swing axis. The tool is fed at a predetermined feed rate while swinging at a predetermined frequency along a plane parallel to the feed direction with the center of the nose as a swing axis, and at the same time, 1 of the material to be machined. It is characterized by having a feeding means and a control means for controlling the operation of the swinging means so that the phase of the swing is deviated with each rotation.

In the cutting apparatus of the present invention, in the above configuration, the control means shifts the phase of the vibration by 180 degrees for each rotation of the work material, and at a position corresponding to the outer peripheral surface of the work material. The operation of the feeding means and the swinging means is controlled so that the width of the vibration of the tool due to the swing is larger than the feed amount of the tool in the feed direction per rotation of the work material. It is preferable to do so.

The control method of the cutting device of the present invention is a control method of a cutting device that presses the cutting edge of a tool against a work material rotating around an axis to cut the work material, and the tool is used on the cutting edge. While swinging at a predetermined frequency along a plane parallel to the feed direction with the center of the arcuate nose as the swing axis, the feed operation is performed at a predetermined feed rate in the feed direction, and one rotation of the work piece is performed. It is characterized in that the phase of the swing is shifted each time.

In the above configuration, the control method of the cutting device of the present invention shifts the phase of the vibration by 180 degrees for each rotation of the work material, and at the same time, the tool at a position corresponding to the outer peripheral surface of the work material. It is preferable to swing the tool so that the width of the vibration due to the swing is larger than the feed amount of the tool in the feed direction per rotation of the work material.

According to the present invention, by swinging the tool around the center of the arcuate nose of the cutting edge as a swing axis, a thin portion or a cut is generated in the chip generated by the cutting process, and the chip is divided. Since it is made easy, the accuracy is the same as when the tool is fed without vibrating in the feed direction while keeping the grain of the tool on the machined surface of the work material constant while improving the workability of chips. Can be machined with.
Therefore, according to the present invention, it is possible to provide a cutting device capable of improving the processability of chips without lowering the processing accuracy and a control method thereof.

It is a figure which shows roughly the structure of the cutting apparatus of one Embodiment of this invention. It is a figure which shows the state of cutting a work material by a tool. It is an enlarged figure which shows the cutting edge of the tool which cuts a work material. It is a figure for demonstrating the rotation of a rotation table and the moving direction of the rotation center axis at the time of swinging a tool around the center of an arcuate nose as a swing axis. It is a figure which shows a part of a chip generated by a cutting process. It is a figure which shows the modification of the rocking means.

Hereinafter, embodiments of the present invention will be illustrated in detail with reference to the drawings.

The cutting apparatus 1 of the embodiment of the present invention shown in FIG. 1 is configured as an automatic lathe, and has a processing unit 2 which is an apparatus main body and a control unit 3 as a control means.

The processing unit 2 has a spindle 10 rotatably supported by a spindle (not shown) mounted on the bed 4. The spindle 10 is arranged in a posture in which its rotation center axis extends along the Z-axis direction. Although details are not shown, the spindle base is provided with a spindle drive mechanism using a spindle motor as a drive source, and the spindle 10 is driven by the spindle drive mechanism to rotate.

As the spindle drive mechanism, for example, a mechanism using a built-in type electric motor arranged so as to surround the spindle 10 inside the spindle base as a drive source can be adopted.

A chuck 11 is provided at the tip of the spindle 10, and the material (work) 12 to be processed can be fixedly held on the spindle 10 by using the chuck 11. As the work material 12, for example, a cylindrical metal round bar can be used. The workpiece 12 is fixedly held to the spindle 10 by the chuck 11 in a posture in which the axis L coincides with the rotation center axis of the spindle 10. By rotating the spindle 10 while the workpiece 12 is fixedly held or supported, the workpiece 12 can be rotated around its axis L.

The machined portion 2 has a tool (cutting tool) 13 for cutting the work piece 12. The tool 13 includes, for example, a tool body (shank) 13a having a rectangular cross-section and a cutting edge 13b provided at the tip of the tool body 13a. In the present embodiment, the tool 13 is configured as a replaceable tip in which the cutting edge 13b is detachably fixed to the tool body 13a, but the tool body 13a is integrally provided with the cutting edge 13b as the tool 13. It is also possible to use the one having the same configuration.

The tool 13 is fixedly held on the tool base 14 in the tool body 13a. The tool 13 is in a posture in which the cutting edge 13b is oriented toward the rotation center axis side of the spindle 10 (the side of the axis L), and the cutting edge 13b projects outward from the outer peripheral edge of the tool base 14.

The tool base 14 is mounted on the tool moving body 15, and the tool moving body 15 is mounted on the XZ stage 16.

The X-Z stage 16 is provided with an X-axis drive mechanism 16a. By driving the tool moving body 15 in the X-axis direction, the X-axis drive mechanism 16a can move the tool 13 together with the tool moving body 15 and the tool base 14 in the direction of approaching and separating from the axis L (X-axis direction). can.

The XZ stage 16 is provided with a Z-axis drive mechanism 16b. By driving the tool moving body 15 in the Z-axis direction, the Z-axis drive mechanism 16b can move the tool 13 together with the tool moving body 15 and the tool base 14 in the direction along the axis L (Z-axis direction). That is, in the present embodiment, the Z-axis drive mechanism 16b corresponds to a feeding means for feeding the tool 13 in the feeding direction along the axis L.

The X-axis drive mechanism 16a and the Z-axis drive mechanism 16b include, for example, a ball screw mechanism arranged along the Z-axis direction or the X-axis direction, and a drive source such as a pulse motor or a stepping motor for driving the ball screw mechanism. It is possible to adopt the one having the same configuration.

By moving the tool 13 in the X-axis direction and the Z-axis direction, the cutting device 1 presses the cutting edge 13b of the tool 13 against the workpiece 12 driven by the spindle 10 and rotates around the axis L to be covered. The machined material 12 is machined. More specifically, as shown in FIG. 2, in the cutting device 1, the tool 13 is rotated in the X-axis direction by the X-axis drive mechanism 16a in a state where the workpiece 12 is rotated around the axis L together with the spindle 10. By moving the tool 13 to set the cutting depth of the cutting edge 13b with respect to the workpiece 12, and then using the Z-axis drive mechanism 16b to feed the tool 13 in the feed direction along the axis L at a predetermined speed, the axis L is fed. The cutting edge 13b of the tool 13 is pressed against the workpiece 12 rotating around from the axial direction to cut (turn) the workpiece 12.

The cutting device 1 uses the tool 13 as a plane parallel to the feed direction with the center of the arcuate nose 13c of the cutting edge 13b as the swing axis (in the present embodiment, a plane parallel to both the X-axis and the Z-axis). By swinging along the axis L and feeding it along the axis L, the processability of chips generated during cutting is improved. Therefore, the cutting device 1 has a swinging means for swinging the tool 13 with the center of the arcuate nose 13c as a swinging axis.

Here, as shown in FIG. 3, the nose 13c, which is a portion of the cutting edge 13b of the tool 13 protruding toward the most axis L side, has an arc shape having a radius R when viewed from the Y-axis direction. The center of the nose 13c is a center position that is the starting point of the radius R of the arc-shaped nose 13c, and the center position is the swing axis S. The portion connected to the nose 13c of the cutting edge 13b and facing the front side in the feeding direction is a linear cutting edge portion 13d, and the workpiece 12 is cut by the nose 13c and the cutting edge portion 13d. The portion of the cutting edge 13b that is connected to the nose 13c and faces the side opposite to the feeding direction of the cutting edge 13b is the back surface portion 13e, and the back surface portion 13e is in the Z-axis direction so as not to come into contact with the workpiece 12 during cutting. On the other hand, it is provided with a predetermined clearance angle.

In the present embodiment, the swinging means is composed of an X-axis drive mechanism 16a, a Z-axis drive mechanism 16b, and a rotation mechanism 17.

As shown in FIG. 1, the tool base 14 is rotatably supported by the tool moving body 15 about a rotation center axis O extending along a Y axis perpendicular to both the X axis and the Z axis. The rotation mechanism 17 drives the tool base 14 in the turning direction to swing the tool 13 in a predetermined angle range and a predetermined frequency around the rotation center axis O. As the drive source of the rotation mechanism 17, for example, a pulse motor, a stepping motor, or the like can be used.

In the present embodiment, since the center of the nose 13c of the cutting edge 13b of the tool 13 is displaced from the rotation center axis O and fixedly held on the tool base 14, the tool 13 is rotated around the rotation center axis O. If only the cutting edge 13b is moved, the position of the nose 13c of the cutting edge 13b will be displaced in both the X-axis direction and the Z-axis direction, and the tool 13 will be parallel to the feed direction with the center of the nose 13c of the cutting edge 13b as the swing axis S. It cannot be rocked along a surface. Therefore, in the cutting device 1 of the present embodiment, as shown in FIG. 4, the tool 13 is centered on the rotation center axis O from the posture in which the cutting edge portion 13d is perpendicular to the feed direction (Z-axis direction). In FIG. 4, the coordinates P1 (x1, z1) of the rotation center axis O with the center of the nose 13c as the origin become the coordinates P2 (x2, z2) while rotating in the clockwise direction by an angle θ. By moving in the X-axis direction and the Z-axis direction, the tool 13 is swung along a plane parallel to the feed direction with the center of the nose 13c of the cutting edge 13b as the swing axis S.

Here, the coordinates P2 (x2, z2) after the movement of the rotation center axis O are the coordinates P1 (x1, z1), the rotation angle θ around the rotation center axis O of the tool table 14, and the nose 13c. It can be calculated by the following equation using the radius R of.

(X2, z2) = (x1 · cosθ + z1 · sinθ + R (1-cosθ−sinθ), x1 · sinθ + z1 · cosθ + R (1-cosθ−sinθ))

Based on this equation, while rotating the tool 13 about the rotation center axis O by an angle θ, the rotation center axis O is moved in the X-axis direction by the difference in coordinates in the X-axis direction (x2-x1). By moving the rotation center axis O in the Z-axis direction by the difference in coordinates in the Z-axis direction (z2-z1), the tool 13 is parallel to the feed direction with the swing axis S as the center. It can be rotated along a surface.

At this time, the tool 13 is not only swung around the swing shaft S by the swing means, but also is fed along the axis L with the tool base 14 by the Z-axis drive mechanism 16b which is the feed means with a predetermined feed amount. Since the feed operation is performed in the direction, the position of the coordinate P2 (x2, z2) after the movement is set in consideration of the amount of movement in the Z-axis direction due to the feed operation.

Then, by performing the control opposite to the above, the tool 13 can be rotated to the original position about the swing shaft S, and by repeating the rotation, the tool 13 is shaken. It can be swung along a plane parallel to the feed direction with the moving axis S as the center.

The control unit 3 is configured as, for example, a microcomputer equipped with a CPU. Before cutting, the control unit 3 uses an input means (not shown) such as a touch panel display or a keyboard to set cutting conditions such as the rotation speed of the spindle 10, the cutting depth D, and the feed rate in advance. In addition, tool information such as the value of the radius R of the nose 13c, the position of the nose 13c, the swing angle θ around the swing axis S of the tool 13, and the frequency is input.

Using the above information, the control unit 3 uses the above information to rotate the spindle 10 (operation of the spindle motor), move the tool moving body 15 (operate the X-axis drive mechanism 16a and the Z-axis drive mechanism 16b), and rotate the tool base 14. (Operation of the rotating mechanism 17) is controlled in an integrated manner, and the tool 13 is swung at a predetermined frequency along a plane parallel to the feed direction with the center of the nose 13c as the swing axis S. The feed operation is performed at the feed speed to execute the cutting process of the workpiece 12. That is, when the cutting device 1 presses the cutting edge 13b of the tool 13 against the workpiece 12 rotating around the axis to cut the workpiece 12, the tool 13 is the center of the arcuate nose 13c of the cutting edge 13b. Is controlled by the control unit 3 so as to be fed at a predetermined feed rate in the feed direction while swinging at a predetermined frequency along a plane parallel to the feed direction along the axis L with the swing axis S as the swing axis S.

Here, the swing around the swing shaft S of the tool 13 is controlled so as to be continuously performed at a predetermined frequency during cutting. The frequency can be appropriately set according to the cutting conditions and the like, but it is preferably set in the range of several hertz to several hundred hertz. Further, in any case, the frequency of the swing around the swing shaft S of the tool 13 is set so that the phase of the swing shifts every time the spindle 10 or the workpiece 12 makes one rotation. Will be done.

As described above, in the cutting device 1 of the present embodiment, the tool 13 is fed while swinging at a predetermined frequency with the center of the nose 13c as the swing axis S, and every rotation of the workpiece 12 is performed. By shifting the phase of the vibration, the amount of cut in the feed direction of the cutting edge portion 13d with respect to the workpiece 12 is changed, and the chips generated from the workpiece 12 cut by the tool 13 are removed. , It can be easily divided with a thin portion. As a result, the discharged chips can be easily divided in the thin portion, and the processability of the chips can be improved. Further, since the tool 13 is swung at a predetermined frequency with the center of the nose 13c as the swing axis S to improve the processability of chips, the tool 13 is directed toward the nose 13c in the feed direction depending on the swing. Cutting can be performed by feeding the nose 13c at a constant feed rate so as not to cause misalignment. Therefore, the machining of the workpiece 12 can be performed with the same high accuracy as when the tool 13 is fed at a constant speed without swinging, while the grind of the tool 13 on the machining surface of the workpiece 12 is constant. It can be carried out. As described above, according to the cutting apparatus 1 of the present embodiment, the chips can be easily separated without lowering the machining accuracy of the workpiece 12 by the tool 13, and the processability thereof can be improved.

In the above configuration, the control unit 3 shifts the swing phase of the tool 13 around the swing shaft S by 180 degrees each time the spindle 10 or the workpiece 12 makes one rotation. At the same time, the width W of the vibration due to the swing of the tool 13 at the position corresponding to the outer peripheral surface of the work material 12 (the position corresponding to the cutting depth D in the work material 12 in FIG. 3) is the work material 12. It is preferable to control the rotation of the spindle 10, the movement of the tool moving body 15, and the rotation of the tool base 14 so as to be larger than the feed amount of the tool 13 in the feed direction per rotation. With such a configuration, the cutting edge portion 13d of the tool 13 may have a gap period in which the cutting edge portion 13d does not come into contact with the machined portion one lap before, and the chips 20 may have a cut as shown in FIG. can. Even in this case, since the amplitude due to the swing does not occur in the nose 13c portion of the cutting edge 13b, the chips 20 are connected on one side in the width direction, but the chips 20 are further bent due to the cut. The processability can be improved by making it easy and easy to divide.

The width W of the vibration due to the swing of the tool 13 at the position corresponding to the outer peripheral surface of the workpiece 12 is W = where the cutting depth is D, the radius of the nose 13c is R, and the swing angle is θ. It is calculated by (DR) × tanθ−R (1-1 / cosθ).

For the distance between adjacent cuts that do not have a large cut, the swing angle θ or vibration width W of the tool 13, the vibration frequency, the phase shift of the swing of the workpiece 12 for each rotation, etc. It can be changed by adjusting. For example, even if the phase shift of the vibration of the work material 12 per rotation is small, the chip 20 is cut by setting a large vibration angle θ or vibration width W of the tool 13. Can be. Further, the vibration angle θ or the vibration width W of the tool 13 is set so that an appropriate cut is generated in the chip 20 based on the feed amount per rotation and the cutting depth D of the workpiece 12 of the tool 13. It can be set as appropriate.

The swing range centered on the swing axis S of the tool 13 is centered on the rotation center axis O with respect to the posture in which the cutting edge portion 13d is perpendicular to the feed direction (Z-axis direction) in FIG. Not limited to the clockwise side, the cutting edge portion 13d reaches the counterclockwise side centered on the rotation center axis O with respect to the posture perpendicular to the feed direction (Z-axis direction). It can also be set as. In this case, the swing angle is set within a range in which the back surface portion 13e of the cutting edge 13b does not come into contact with the machined surface of the workpiece 12.

FIG. 6 is a diagram showing a modified example of the swinging means. In FIG. 6, the members corresponding to the above-mentioned members are designated by the same reference numerals.

In the case shown in FIG. 1, the swinging means is composed of an X-axis drive mechanism 16a, a Z-axis drive mechanism 16b, and a rotation mechanism 17, and the tool 13 is rotated by the rotation mechanism 17 while rotating the X-axis. The drive mechanism 16a and the Z-axis drive mechanism 16b are moved in the X-axis direction and the Z-axis direction so as to swing around the swing axis S. On the other hand, in the modified example shown in FIG. 6, the rotation center axis O that rotatably supports the tool base 14 on the tool moving body 15 is configured to coincide with the swing axis S. According to the configuration of the modified example shown in FIG. 6, the tool 13 is swung around the rotation center axis O together with the tool base 14 without moving the tool moving body 15 in the X-axis direction and the Z-axis direction. , The tool 13 can be swung around the center of its nose 13c as a swing axis S. In this case, the tool 13 is fixedly held on the tool base 14 via the spacer 14a to provide a gap between the cutting edge 13b of the tool 13 and the tool base 14, so that the work material 12 is arranged at the gap. As a result, the configuration can be constructed without bringing the tool base 14 into contact with the workpiece 12. According to the configuration of the above modification, the configuration of the cutting device 1 can be simplified and its cost can be reduced.

It goes without saying that the present invention is not limited to the above-described embodiment and can be variously modified without departing from the gist thereof.

For example, the feeding means for feeding the tool 13 in the feeding direction is not limited to the above configuration, and various configurations can be used. Similarly, various means of swinging the tool 13 along a plane parallel to the feed direction with the center of the arcuate nose 13c of the cutting edge 13b as the swing axis S are not limited to the above configuration. The configuration can be used.

Further, the radius R of the nose 13c of the cutting edge 13b of the tool 13 can be variously changed, for example, from several tens of μm to several hundreds of μm, but the radius R of the nose 13c can also be set to 0. In this case, the tool 13 swings around a sharp tip portion where the cutting edge portion 13d and the back surface portion 13e of the cutting edge 13b intersect, and the same effect as described above is obtained by the configuration. be able to.

Further, in the above-described embodiment, the feeding direction of the tool 13 by the feeding means is set to be along the axis L of the spindle 10 or the workpiece 12, but the feeding direction of the tool 13 is not limited to this, for example, the axis line. Various changes can be made, such as the direction of inclination with respect to L.

1 Cutting device 2 Machining part 3 Control part 4 Bed 10 Spindle 11 Chuck 12 Work material 13 Tool 13a Tool body 13b Cutting edge 13c Nose 13d Cutting edge part 13e Back part 14 Tool stand 14a Spacer 15 Tool moving body 16 X-Z stage 16a X-axis drive mechanism 16b Z-axis drive mechanism 17 Rotation mechanism 20 Chips L Axis S Swing axis O Rotation center axis D Cutting depth R Nose radius W Vibration width

Claims (4)

It is a cutting device that cuts the work material by pressing the cutting edge of the tool against the work material that rotates around the axis.
A spindle that rotates the work material around the axis, and
A feeding means for feeding the tool in the feeding direction and
A swinging means for swinging the tool along a plane parallel to the feed direction with the center of the arcuate nose of the cutting edge as the swinging axis.
The tool is fed at a predetermined feed rate while swinging at a predetermined frequency along a plane parallel to the feed direction with the center of the nose as a swing axis, and every rotation of the work piece. A cutting device comprising: a feeding means and a control means for controlling the operation of the swinging means so that the swinging phase is deviated from the ground. The control means
The phase of the swing is shifted by 180 degrees for each rotation of the work material, and the phase of the swing is shifted by 180 degrees.
The width of the vibration due to the swing of the tool at the position corresponding to the outer peripheral surface of the work material is larger than the feed amount of the tool in the feed direction per rotation of the work material. The cutting device according to claim 1, which controls the operation of the feeding means and the swinging means. It is a control method of a cutting device that presses the cutting edge of a tool against a work material that rotates around an axis to cut the work material.
The tool is swung at a predetermined frequency along a plane parallel to the feed direction with the center of the arcuate nose of the cutting edge as a swing axis, and is fed at a predetermined feed rate in the feed direction. A method for controlling a cutting device, which comprises shifting the phase of the vibration for each rotation of the material to be processed. The phase of the swing is shifted by 180 degrees for each rotation of the work material, and the phase of the swing is shifted by 180 degrees.
The width of the vibration of the tool due to the swing at the position corresponding to the outer peripheral surface of the work material is larger than the feed amount of the tool in the feed direction per rotation of the work material. The control method for a cutting device according to claim 3, wherein the tool is swung.

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