JP2017013152A - Curved surface cutting apparatus - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a curved surface cutting apparatus capable of cutting a curved surface with a high degree of accuracy.SOLUTION: A surface-to-be-cut 101 of a workpiece 100 is cut by a cutting tool 36. A curved surface cutting apparatus includes control means for performing control so that a cutting face of the cutting tool 36 can be positioned in a plane orthogonal to a cutting direction of the cutting tool 36, in a state in which the cutting face is positioned on a normal line passing through a cutting point.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a curved surface cutting apparatus for cutting a curved surface such as a concave surface or a convex surface with a cutting tool.

  This type of cutting apparatus is disclosed in Patent Document 1. The device disclosed in Patent Document 1 performs an edging process on a surface to be cut of a workpiece by a cutting tool, and discloses an example in which the cutting tool is moved in the X-axis direction and the workpiece is moved in the Z-axis direction. ing.

JP 2003-231001 A

  In the apparatus of Patent Document 1, when the surface to be cut of a workpiece is a curved surface, no means for finishing the curved surface with high accuracy is disclosed. Therefore, in the configuration of Patent Document 1, it is difficult to perform cutting on a curved surface with high accuracy.

  An object of the present invention is to provide a curved surface cutting apparatus capable of performing cutting on a curved surface with high accuracy.

  In order to achieve the above object, in the present invention, a curved surface cutting apparatus for cutting a surface to be cut of a workpiece made of a curved surface with a cutting tool, wherein the rake face of the cutting tool is positioned on a normal line passing through a cutting point. And a control means for controlling the rake face to be positioned in a plane perpendicular to the cutting direction of the cutting tool.

  With this configuration, during cutting of the workpiece, the cutting face of the cutting tool is located in a plane perpendicular to the cutting direction of the cutting tool on the normal line at the cutting point, so that high-precision cutting is possible regardless of the position and shape of the curved surface. Processing becomes possible.

  According to the present invention, there is an effect that a curved surface of a workpiece can be cut with high precision by a cutting tool.

The perspective view of a curved surface cutting device. The partial front view of a curved surface cutting device. The perspective view of a cutting head. The block diagram which shows the electric constitution of a curved surface cutting device. Explanatory drawing which shows the cutting state of a curved surface cutting device. Explanatory drawing which similarly shows the cutting state of a curved surface cutting device. Explanatory drawing which shows the relationship between a rake face and cutting progress direction. Explanatory drawing which shows the relationship between a rake face and an A-axis. Explanatory drawing which similarly shows the relationship between a rake face and an A-axis. The flowchart which shows operation | movement of a curved surface cutting device.

Embodiments of a curved surface cutting apparatus embodying the present invention will be described below with reference to the drawings.
As shown in FIGS. 1, 2 and 4, a moving table 12 is supported on a machine base 11 of the apparatus, and this moving table 12 serves as a horizontal first axis by a Y-axis motor 13 shown in FIG. Is reciprocated in the Y-axis direction. A table 14 is supported on the movable table 12, and the table 14 is rotated around a vertical C axis as a second axis by a C axis motor 15.

  A cross beam 17 extending in the horizontal direction via a column 16 is installed above the machine base 11. A movable body 18 is supported on the cross beam 17, and the movable body 18 is reciprocated in a horizontal X-axis direction as a third axis perpendicular to the Y-axis by an X-axis motor 19. A lift body 20 is supported on the moving body 18, and the lift body 20 is lifted and lowered in a vertical Z-axis direction as a fourth axis by a Z-axis motor 21.

  As shown in FIGS. 2 to 4, a lifting head 20 supports a cutting head 22, and this cutting head 22 is a shaft serving as a horizontal fifth axis parallel to the Y axis by a B-axis motor 23. Rotated around 24. This shaft 24 is defined as a B-axis.

  As shown in FIGS. 2 and 3, a head body 32 is supported on the frame 30 of the cutting head 22, and this head body 32 is a shaft serving as a sixth axis perpendicular to the B axis by a D-axis motor 33. It is rotated around 31. This axis 31 is defined as the D axis.

  As shown in FIGS. 2 and 3, the head body 32 supports a bite shaft 34 extending in a direction perpendicular to the D axis when viewed from the extending direction of the D axis. The bite shaft 34 is an A-axis motor 35. Is rotated within a range of 360 degrees about the A axis passing through the cutting edge 362 of the cutting tool 36 as the seventh axis. By this rotation, the direction of a rake face 361 of a cutting tool 36 to be described later is changed.

  As shown in FIG. 10, the frame 30 is reciprocated in the A-axis direction by a linear motor 37, and the position of the cutting tool 36 in the A-axis direction is adjusted. A cutting tool 36 is detachably attached to the lower end of the cutting tool shaft 34. As shown in FIGS. 6 to 9, the cutting tool 101 on the surface of the work 100 is brought into contact with the cutting tool 36 by the linear motor 37. The cutting tool 361 and the cutting edge 362 of the cutting tool 36 are located on the A axis.

  Accordingly, the workpiece 100 on the table 14 is moved in the horizontal Y-axis direction by the Y-axis motor 13 and rotated around the C-axis parallel to the vertical Z-axis by the C-axis motor 15. This rotation is for moving the cutting position, and is a low-speed rotation. The cutting tool 36 is moved in the horizontal X-axis direction by the X-axis motor 19 and is moved up and down in the vertical direction by the Z-axis motor 21. Further, the cutting tool 36 is rotated around the B axis parallel to the Y axis by the B axis motor 23, and rotated around the D axis perpendicular to the B axis by the D axis motor 33. As described above, the direction of the rake face 361 of the cutting tool 36 on the A axis is changed.

  Therefore, the workpiece 100 and the cutting tool 36 can be relatively moved in the three-axis directions of X, Y, and Z. Further, the cutting tool shaft 34, that is, the cutting tool 36 is movable in the three axis directions A, B, and D with respect to the cut surface 101 of the workpiece 100 shown in FIG. Then, according to the curved surface shape of the surface to be cut 101, the rake face 361 of the cutting tool 36 is arranged at a position on the normal line L at the cutting point of the surface to be cut 101. In addition, the cutting tool 36 is maintained by the action of the control device 51 described later so that the rake face 361 is perpendicular to the cutting progress direction, that is, facing forward in the cutting progress direction (see FIG. 7).

  The control device 51 that constitutes the control means and the calculation means includes a control unit 52 composed of a CPU (Central Processing Unit) and the like, and a storage unit 53. The control device 51 performs the operations of the Y-axis motor 13, C-axis motor 15, X-axis motor 19, Z-axis motor 21, B-axis motor 23, D-axis motor 33, A-axis motor 35, and linear motor 37. Control.

The storage unit 53 stores various types of data such as the program shown in FIG. Then, the program is executed under the control of the control unit 52.
Next, the operation of the curved surface cutting apparatus of the embodiment will be described.

  When the cutting of a curved surface, for example, a spherical surface, of the workpiece 100 is started in step (hereinafter abbreviated as S) 1 in FIG. 10, the cutting tool 36 is a normal line passing through the cutting point as shown in FIGS. 5 and 6. Held on L. When the angle of the cutting tool 36, that is, the position of the normal L is changed in S2, the direction of the rake face 361 of the cutting tool 36 in the cutting progress direction is set in S3.

That is, as shown in FIG. 8, the length of the distance from the rotation center of the B-axis (axis 24) as the fifth axis to the cutting edge of the cutting tool 36 is “H”. Further, the angle of the cutting edge 362 of the cutting tool 36 around the B axis is assumed to be “B”. A indicates the angle of the cutting edge 362 of the cutting tool 36 around the A axis as the seventh axis. X is the position in the X direction which is the third axis direction shown in FIG. 1, and the origin is the point where the rotation center of the C axis which is the second axis coincides with the position of the cutting edge 362 of the cutting tool 36 in the state of B = 0. . Y is the position in the Y direction which is the first axis direction, and V _X · V _Y · V _Z is the drive of the X (third axis) · Y (first axis) · Z (fourth axis) axis shown in FIG. V _B and V _C are angular velocities of the B (fifth axis) and C (second axis) axes shown in FIG.

That is, B-axis rotation center to tool tip height (distance) ... H
A-axis rotation center to tool tip eccentricity 0
The origin of the A axis is the X + direction. The origin of the B axis is the downward direction. The origin of the X and Y axes is where B = 0 and the tool tip coincides with the C axis rotation center. The origin of the Z and C axes is arbitrary. Tool speed: v _tool
v _toolX = v _X -Hv _B cosB
v _toolY = 0
v _toolZ = v _Z + Hv _B sinB
Work speed: v _work
v _workX = Rv _C sinC '= Yv _C
v _workY = v _Y + Rv _c cos _C ′ = v _Y + (X−H sin B) v _C
v _workZ = 0
However, the distance between the C axis and the tool tip (R) R ² = (X−H sin B) ² + Y ²
Tool tip direction viewed from C axis tanC '= Y / (X-HsinB)
Speed difference between tool and workpiece: V
V _X = v _toolX -v _workX = v _X -Hv _B cos _B -Yv _C
V _Y = v _toolY −v _workY = −v _Y − (X−HsinB) v _C
V _Z = v _toolZ -v _workZ = v _Z + Hv _B sinB
Speed difference in the orthogonal system (coordinate system tilted by B) with the Y-axis as the Y′-axis and the A-axis rotation axis as the Z′-axis: V ′
V ′ _X = V _X cosB−V _Z sinB
_{= (V X -Hv B cosB-} Yv C) cosB- (v Z + Hv B sinB) sinB
_{= (V X -Yv C) cosB} -v Z sinB-Hv B
_V'Y = _{V Y}
= -V _Y- (X-HsinB) v _{C
V'Z = V Z cosB + V} X sinB
= Omitted because it is not used Direction of velocity vector in the plane with A-axis as normal
tanA = −V ′ _Y / V ′ _X
Therefore,

The calculation is executed so that the relationship of the expression (1) is maintained. If the direction of the cutting tool 36 is set according to the calculation result, the rake face 361 is maintained at a right angle to the cutting progress direction even if the position of the work surface 101 of the workpiece 100 is changed.

  As described above, even when the cutting position of the workpiece with respect to the surface to be cut is changed, the rake face 361 of the cutting tool 36 is arranged in a plane perpendicular to the cutting progress direction. Therefore, a good sharpness can be maintained with high accuracy regardless of the position of the surface to be cut.

Then, in S4, it is determined whether or not machining has been completed. If the machining has not been completed, the process returns to S1 and the program is terminated upon completion of machining.
Therefore, this embodiment has the following effects.

  (1) Even if the cutting position of the workpiece 100 with respect to the surface to be cut 101 is changed, the rake face 361 of the cutting tool 36 is arranged in a plane perpendicular to the cutting progress direction. Therefore, regardless of the position of the cut surface 101, it is possible to maintain a good sharpness with high accuracy.

  (2) In order to maintain the rake face 361 of the cutting tool 36 in a plane orthogonal to the cutting progress direction, the cutting tool 36 is only maintained based on the formula (1). Can be avoided.

(3) Since the rake face 361 of the cutting tool 36 is maintained on the normal line L, high-precision machining becomes possible.
The present invention is not limited to the above embodiment, and can be embodied in the following aspects.

  The curved surface cutting device of the above embodiment is used for cutting a convex curved surface other than a spherical surface, or a spherical curved surface or an aspherical concave curved surface. Also in this case, the direction of the rake face 361 of the cutting tool 36 can be adjusted by using the equation (1).

  -Instead of the linear motor 37 for adjusting the position of the cutting tool 36, use a servo motor and a screw feed mechanism operated by the servo motor.

  36: Bite, 100: Workpiece, 101: Surface to be cut, 361: Rake face, 362: Cutting edge, L: Normal.

Claims (5)

A curved surface cutting device for cutting a cut surface of a workpiece made of a curved surface with a cutting tool,
A curved surface cutting apparatus provided with control means for controlling the rake face to be positioned in a plane perpendicular to the cutting direction of the cutting tool in a state where the rake face of the cutting tool is located on a normal line passing through the cutting point of the curved surface.   The work is supported so as to be movable in the first axis direction, and is supported so as to be rotatable around a second axis orthogonal to the first axis. The tool is supported at a right angle to the first axis and the second axis. Supports movement in three axis directions and movement in a fourth axis direction parallel to the second axis, and further enables the bite to rotate around a fifth axis parallel to the first axis. The curved cutting apparatus according to claim 1, wherein the cutting tool is rotatable about a sixth axis parallel to the third axis, and the cutting tool is rotatable about a seventh axis passing through a cutting edge at the tip. . The control means includes
The length of the distance from the fifth axis to the cutting edge of the cutting tool is H, the angle of the cutting edge of the cutting tool centered on the fifth axis is B, and the angle of the cutting edge of the cutting tool about the seventh axis A, the point where the position of the cutting edge of the cutting tool coincides with the rotation center of the second axis at the position of the third axis and the angle B = 0 at the position in the third axis direction as the origin, and from the origin to the first axis direction The position is Y, the driving speeds of the third axis, the first axis, and the fourth axis are V _X , V _Y, and V _Z , respectively, and the angular velocities of the fifth axis and the second axis are V _B and V _{C, respectively.} If
The curved surface cutting device according to claim 2, wherein the angle of the rake face of the cutting tool is adjusted based on the above formula.   The curved surface cutting device according to claim 2 or 3, wherein the second axis is installed on a vertical line.   The curved cutting apparatus according to claim 4, wherein the cutting tool is provided at an upper position of the workpiece.