JPH07100752A - Curved surface working device - Google Patents

Abstract

PURPOSE:To improve the curved surface formation precision having the less influence of thermal deformation by maintaining the relation of direction between the normal line of the free curved surface and a grinding wheel head at the contact point between a workpiece and a grinding wheel, always in the same state independently of the change of the normal line of the free curved surface. CONSTITUTION:A grinding wheel head 18 is swung by a prescribed angle around the A axis each time when a worktable 24 including a workpiece W is pitch-fed in the Y-axis direction, and in this state, the worktable 24 is including the workpiece W is cut-in-fed in the Z-axis direction through the traverse feed in the X-axis direction of a slide table 12 for grinding wheel including the grinding wheel head 18, and at the same time, the workpiece W is curved- surface-worked by swinging the grinding wheel head 18 around the B-axis.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a curved surface processing apparatus for processing a free curved surface such as an anamorphic curved surface.

[0002]

2. Description of the Related Art Conventionally, for example, when a molding die for a lens having an anamorphic curved surface is curved, as shown in FIG. 5, a grinding stone 2 having a substantially hemispherical shape is attached to a machining center or a grinding center 1. Put on the work piece 3
By moving the grindstone 2 in the Z-axis direction while cutting is moved in the X-axis direction, one-pass machining is performed in the X-axis direction.
When the one-pass machining is completed, the workpiece 3 is moved by one pitch in the Y-axis direction, and the one-pass machining is performed again by simultaneous two-axis control in the X-axis and Z-axis directions. Thereafter, similarly, as shown in FIG. 6, the grindstone 2 is traversed relative to the workpiece 3 to machine the entire surface of the workpiece 1 into a curved surface.

[0003]

In the conventional curved surface machining apparatus as described above, since the grindstone 2 has a substantially hemispherical shape, the curved surface machining of the workpiece 3 is performed by simultaneous biaxial control of the X axis and the Z axis. The contact direction between the workpiece and the grindstone changes with each one-pass machining. Therefore, if the radius of the grindstone 2 is not truly trued, the truing accuracy of the radius is reflected in the creation accuracy of the workpiece. Further, in the vicinity of the apex 3a located at the center of the curved surface of the workpiece 3, since the peripheral speed of the grindstone 2 is close to zero, it is difficult to process and the shape accuracy of the curved surface is adversely affected. Furthermore, since the grinding center on which the grindstone 2 is mounted and the cutting feed direction of the grindstone are the same, when thermal deformation occurs in the grinding center in the axial direction, this thermal deformation acts on the cutting feed, and the shape of the workpiece is cut. There was a problem that adversely affected the accuracy.

The present invention has been made in view of the above points, and it is possible to always maintain the contact direction between the workpiece and the grindstone in the same state, and to improve the accuracy of curved surface generation with less influence of thermal deformation. An object is to provide a curved surface processing device.

[0005]

In order to achieve the above object, the present invention is a curved surface processing apparatus for processing a three-dimensional free curved surface on a workpiece with a disk-shaped grindstone, and a support portion for supporting the workpiece. A grindstone head having a disk-shaped grindstone that is rotationally driven, and a relative movement of the support portion and the grindstone head in a cutting feed direction in which the workpiece and the grindstone come into contact with and separate from each other.
Drive means, second driving means for relatively moving the support portion and the grindstone head in a traverse feed direction perpendicular to the cutting feed direction, and the support portion and the grindstone in a pitch feed feed direction perpendicular to the traverse feed direction. Third driving means for relatively moving the head and a grindstone rotation axis of the grindstone head are arranged in parallel with a B axis perpendicular to the traverse feed direction, and the grindstone head is rotated about the B axis so that the outer circumference of the grindstone is the B axis. And a fourth driving means for swinging the whetstone in contact with the whetstone, and wobbling the whetstone head so that the outer circumference of the whetstone is in contact with the A axis about an A axis that is parallel to the pitch feed feed direction and orthogonal to the B axis. The curved surface shape data is set so that the relationship between the fifth drive means for moving and the normal line of the free curved surface at the point where the workpiece and the grindstone come into contact with the grindstone head is the same even if the normal line of the free curved surface changes. Based on The Te first, second, third, and to configure and control means for controlling the fourth and fifth drive means.

[0006]

In the present invention, the support portion and the grindstone head are relatively pitch-fed by the third driving means,
The fifth driving means swings the grindstone head around the A axis by a predetermined angle for each pitch feed, and the second driving means relatively moves the support portion and the grindstone head in the traverse feeding direction, while Curved machining of a workpiece by simultaneously moving the support portion and the grindstone head by the driving means to give a cutting feed, and at the same time swinging the grindstone head around the B axis according to the curved surface shape data by the fourth driving means. Therefore, even if the normal line of the free-form surface changes, the relationship between the normal line of the free-form surface and the grindstone head can always be maintained in the same state. Therefore, the accuracy of creating the curved surface shape of the workpiece is improved.

[0007]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is a block diagram showing the entire curved surface processing machine and its control unit of the present invention, and FIG. 2 is a side view of a part of the machine. In FIGS. 1 and 2, 10 is a bed, 11 is a grindstone guide table fixed on the bed 10, and the grindstone slide table 12 moves on the guide table 11 in the X-axis direction (traverse feed direction). It is installed as possible.

The slide table 12 for the grindstone is the guide 1
Servomotor 13 installed in 1 and the servomotor 1
It is moved in the X-axis direction by a feed screw mechanism (not shown) rotated by 3.

At the center of the slide table 12, a turntable 14 is provided at a right angle to the X axis by a support mechanism 14a.
The turntable 14 is rotatably installed around a shaft, and the turntable 14 includes a servomotor 15 provided on the support mechanism 14a and a rotation transmission mechanism (not shown) for transmitting the rotation of the servomotor 15 to the turntable 14. Is rotated around the B axis.

An intermediate portion of a bracket 16 which is long in the X-axis direction is fixed on the turntable 14, and between the both ends 16a and 16b of the bracket 16, the grindstone mount 1 is provided.
Both ends of 7 are pivotally supported about an A axis orthogonal to the B axis, and a grindstone head 18 corresponds to the radius of the disk-shaped grindstone 182 from the B axis in an intermediate portion of the grindstone mount 17. It is installed with eccentricity. That is, the outer peripheral circle of the disk-shaped grindstone 182 is in contact with the A axis and the B axis.

The grindstone mount 17 is an end portion 1 of the bracket 16.
Servo motor 19 provided in 6a and servo motor 1
A rotation transmission mechanism (not shown) that transmits the rotation of 8 to the grindstone mount 17 causes it to swing about the A axis. Further, the grindstone head 18 includes a grindstone support member 18 fixed to the grindstone mount 17.
1, a disk-shaped grindstone 182 that is rotatably supported on the support member 181 about an axis orthogonal to the A axis, and the support member 1
An electric motor 183 fixed to 81 for rotating the grindstone 182.
Equipped with.

In FIG. 1 and FIG. 2, 20 is a guide board 1.
1 is a work guide table fixed on the bed 10 on the right side of the table 1. A work slide table 21 is installed on the guide table 20 so as to be movable in the Z-axis direction (cutting feed direction) perpendicular to the X-axis. Has been done. The work slide table 21 includes a servo motor 22 installed on the guide 20.
And a feed screw mechanism (not shown) rotated by the servo motor 23 to move in the Z-axis direction.

A column 23 is vertically installed on the work slide table 21, and a work table 24 is provided on a side surface of the column 23 facing the grindstone head 18, the work table 24 being vertical to the Z axis and parallel to the B axis. It is installed so that it can move in the axial direction (pitch feed feed direction). The work table 24 is moved in the Y-axis direction by a servo motor 25 installed on the column 23 and a feed screw mechanism (not shown) rotated by the servo motor 25. Also,
A workpiece W to be curved is attached to the front surface of the work table 24.

In FIG. 1, reference numeral 30 denotes a numerical control device for controlling and managing the entire curved surface processing machine, to which an input device 31 including a tape reader for reading a processing program and shape data for curved surface processing and a keypad is connected. In addition, the machining program and shape data for curved surface machining (X,
A storage device 32 for storing Y, Z, A, B) is connected.

Further, the numerical controller 30 drives the servo motors 13, 15, 19, 22, 25 by driving command signals output from the numerical controller 30 based on the machining program and the shape data. The circuits 33 to 37 are connected.

In the above structure, the servo motor 13 serves as the second driving means, the servo motor 15 serves as the fourth driving means, the servo motor 19 serves as the fifth driving means, and the servo motor 22 serves as the first driving means. , The servo motor 25 constitutes a third driving means, the numerical controller 30 constitutes a controlling means, and the work table 24 constitutes a supporting portion.

Next, the curved surface processing operation of the present embodiment configured as described above will be described. When machining the workpiece W on a curved surface, first, by operating the numerical control device 30 according to the machining program, a traverse drive command signal corresponding to the curved surface machining shape data (X, Y, Z, A, B) is driven. The grindstone slide table 12 including the grindstone head 18 is moved in the X-axis direction in addition to the servomotor 13 via the circuit 33. In this state, by applying a cutting drive command signal from the numerical control device 30 to the servo motor 22 through the drive circuit 36, the workpiece slide table 21 including the workpiece W is cut and fed in the Z-axis direction, and at the same time, the numerical control device is operated. The turntable 14 is swung around the B-axis by applying a drive command signal corresponding to the angle data B around the B-axis, which is output from 30 according to the traverse feed position in the X-axis direction, to the servomotor 15 through the drive circuit 34. To move the workpiece W to X
One-pass machining in the axial direction.

When the work W is processed in one pass, unless the turntable 14 including the grindstone head 18 is swung about the B axis, the contact point between the grindstone 182 and the work W on the curved surface is from the center of the curved surface. Although it will eventually go to both ends in the direction parallel to the X-axis, which will adversely affect the accuracy of creating the curved surface, but by controlling the turntable 14 including the grindstone head 18 to swing about the B-axis,
The contact point between the grindstone 182 and the workpiece W on the processing curved surface is B
Always kept on axis. As a result, the precision with which the curved surface shape is created is improved.

When the turntable 14 including the grindstone head 18 is controlled to swing about the B axis during the one-pass machining of the work W, the grindstone 182 moves in the longitudinal direction (X) of the work W as shown in FIG. In the direction (parallel to the axis), when relatively moving from one end P1 to the center P of the curved surface, the turntable 14 swings clockwise about the B axis as shown by an arrow D. On the other hand, the grindstone 182 has the center P of the curved surface.
When relatively moving from the other end to the other end P2, the turntable 14 swings counterclockwise as indicated by an arrow E around the B axis.

By performing such processing control, the free-form surface normal F at the contact points P, P1, P2 between the workpiece W and the grindstone 182 and the direction of the grindstone head 18 are changed. Even if it is kept the same.

On the other hand, when the above-described one-pass machining of the workpiece W is completed, a pitch feed drive command signal is applied from the numerical control device 30 to the servo motor 25 through the drive circuit 37 based on the machining program and the shape data, so that the work table 24 is processed. Is moved by one pitch in the Y-axis direction.

Further, by supplying the drive command signal corresponding to the angle data A about the A-axis output from the numerical controller 30 according to the pitch feed position in the Y-axis direction to the servo motor 19 through the drive circuit 35. The grindstone mount 17 including the grindstone head 18 is swung about the A axis by a predetermined angle. As a result, as shown in FIG. 4, the surface 40 that passes through the center 0 of the R portion at the tip of the grindstone and is perpendicular to the grindstone rotation axis L coincides with the normal line F of the free-form surface at the point where the workpiece W and the grindstone 182 contact each other. Let

Therefore, at any pitch feed position, the free-form curved surface normal line F at the contact point between the workpiece W and the grindstone 182 maintains the same relationship as the direction of the grindstone head 18, that is, the rotational axis L of the grindstone. Since the surface 40 orthogonal to each other and passing through the apex of R coincides with the normal line of the free-form surface, even if the normal line of the free-form surface changes, the contact relationship between the normal line of the free-form surface and the grindstone is the same. As described above, the problem caused by the change of the contact direction with the workpiece can be solved.

After the one-pitch feed of the work table 24 in the Y-axis direction is completed, the above-mentioned three-axis control of X, Z and B is performed again to machine the workpiece W in one pass. Hereinafter, by repeating the same operation, the entire surface of the workpiece W is processed into a curved surface according to the curved surface shape data.

In this embodiment as described above, when the grindstone slide table 12 including the grindstone head 18 is moved in the X-axis direction, the work slide table 21 including the workpiece W is cut and fed in the Z-axis direction. At the same time, the turntable 14 including the grindstone head 18 is swung about the B axis to process the workpiece W in one pass, and the work slide table 21 including the workpiece W is moved in the Y axis direction by one pitch. In addition, since the grindstone mount 17 including the grindstone head 18 is swung about the A axis by a predetermined angle and the above-described one-pass machining is repeatedly performed, the contact direction between the workpiece W and the grindstone 182, that is, the contact point is free. The relationship between the normal line F of the curved surface and the direction of the grindstone head 18 can always be kept constant.

As a result, the precision with which the curved surface shape of the workpiece W is created can be improved, and the truing precision at the R portion at the tip of the grindstone is not required so much. Further, since a large disc-shaped grindstone can be used, the influence of the abrasion of the grindstone on the curved surface shape accuracy can be reduced.

Further, since the grindstone 182 is axially supported in the axial direction parallel to the workpiece W, the influence of the elongation due to the heat change of the shaft portion of the grindstone 182 is extremely small, and the accuracy of the curved surface machining of the workpiece is improved. it can. Furthermore, since the grindstone head 18 is swung around the A axis and the B axis so that the outer periphery of the grindstone 182 is in contact with the B axis, even if the grindstone head 18 is swung around the A axis and the B axis, the grindstone 182 and the work piece are machined. Since the contact point of the object W is on the B-axis, it is not necessary to correct the axial position of the work table 24 according to the swing.

The present invention is not limited to the structure shown in the above embodiment, and various modifications can be made without departing from the scope of the claims.

[0029]

As described above, according to the present invention, the grindstone head is swung about the A axis by a predetermined angle according to the curved surface shape data every time the workpiece support portion and the grindstone head are relatively pitch-fed. In this state, while the support portion and the grindstone head are relatively moved in the traverse feed direction, the support portion and the grindstone head are relatively moved in the cutting feed direction, and at the same time, the grindstone head is swung in accordance with the curved surface shape data about the B axis for machining. Since it is configured to process an object, even if the normal of the free-form surface changes when the workpiece and the grindstone contact each other for curved processing, the relationship between the normal of the free-form surface and the grindstone head remains the same. It can be maintained in the state, and the accuracy of creating the curved surface shape of the workpiece can be improved.

Further, by using a disk-shaped grindstone for the grindstone, the influence of elongation due to the thermal displacement of the grindstone shaft is reduced, and the creation accuracy can be expected to be improved. Further, since the grindstone head is swung around the A axis and the B axis so that the outer circumference of the grindstone contacts the B axis, position correction according to the swing becomes unnecessary,
It becomes easy to create curved surface shape data that decides where to move the grindstone head and support.

[Brief description of drawings]

FIG. 1 is a configuration diagram showing an entire curved surface processing machine of the present invention and a control unit thereof.

FIG. 2 is a side view of the partial cutout of FIG.

FIG. 3 is an explanatory diagram showing a contact relationship between a workpiece and a grindstone in the present embodiment.

FIG. 4 is an explanatory diagram showing a contact relationship between a workpiece and a grindstone in the present embodiment.

FIG. 5 is an explanatory diagram showing an example of a conventional curved surface processing apparatus.

FIG. 6 is an explanatory diagram of a conventional curved surface processing method.

[Description of Reference Signs] 12 slide table for whetstone 13 servo motor (second driving means) 14 turntable 15 servo motor (fourth driving means) 16 bracket 17 whetstone mount 18 whetstone head 182 whetstone 19 servomotor (fifth wheel) Driving means) 21 Work slide table 22 Servo motor (first driving means) 23 Column 24 Work table (supporting portion) 25 Servo motor (third driving means) 30 Numerical control device 32 Memory W Workpiece

Claims (1)

[Claims] 1. A curved surface machining apparatus for machining a three-dimensional free-form surface on a workpiece by means of a disk-shaped grindstone, comprising: a support portion for supporting the workpiece; a grindstone head having a disk-shaped grindstone that is rotationally driven; First driving means for relatively moving the support portion and the grindstone head in a cutting feed direction in which the workpiece and the grindstone are brought into contact with each other, and the support portion and the grindstone head in a traverse feed direction perpendicular to the cutting feed direction. Second drive means for relatively moving, third drive means for relatively moving the support portion and the grindstone head in a pitch feed feeding direction perpendicular to the traverse feeding direction, and a traverse feed for a grindstone rotating shaft of the grindstone head. A fourth driving means arranged parallel to the B axis perpendicular to the direction and swinging the grindstone head around the B axis so that the outer periphery of the grindstone contacts the B axis; and the grindstone head. And a free-form surface of a point where the workpiece and the grindstone are in contact with each other, and fifth driving means for swinging the grindstone so that the outer periphery of the grindstone is in contact with the A-axis about the A axis which is parallel to the feed direction and orthogonal to the B axis. Based on the curved surface shape data, the first, second, third, fourth and fifth driving means are set so that the relationship between the normal line of No. 2 and the grindstone head is the same even if the normal line of the free curved surface changes. A curved surface processing apparatus having a control means for controlling.