JPH07100750A - Curved surface working method - Google Patents

Abstract

PURPOSE:To improve the formation precision of the curved surface shape of a workpiece by maintaining the contact direction between a workpiece and a grinding wheel constant. CONSTITUTION:The first swing table 17 is swung by a prescribed angle around the A shaft, each time when a slide table 13 including a workpiece 1 is pitch-fed relatively in the Y-axis direction, and a magnetic head is cut-in-fed in the Z-axis direction, traverse-shifting the slide table 13 including the workpiece in the x-axis direction, and at the same time, the workpiece 1 is worked by swinging the second swing table 22 around the B shaft.

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 method for processing a free curved surface represented by a toroidal curved surface.

[0002]

2. Description of the Related Art FIG. 7 shows an example of a workpiece having a three-dimensional free-form surface represented by a toroidal curved surface. In FIG. 7, reference numeral 1 denotes a workpiece having a toroidal curved surface, and the toroidal curved surface 2 of the workpiece 1 has a curved surface having different curvatures about an axis parallel to the B axis and an axis parallel to the A axis. are doing.

Conventionally, for processing such a toroidal curved surface, a three-axis control type processing machine having a work table moved in the X-axis and Y-axis directions and a disk-shaped grindstone 3 moved in the Z-axis direction. Is used. When processing a toroidal curved surface using such a processing machine, the workpiece 1
While moving in the X-axis direction, the grindstone 3 is cut and fed in the Z-axis direction according to the curved surface shape data to perform one-pass machining. Then, after moving the workpiece 1 by one pitch in the Y-axis direction, the workpiece and the grindstone are simultaneously controlled again in the X-axis and Z-axis directions for one-pass machining. Thereafter, by repeating the same operation, the workpiece is curved according to the curved surface shape data.

[0004]

However, in the conventional processing machine as described above, the toroidal curved surface is machined by the three-axis control. Therefore, when the curved surface is machined, the workpiece 1 is fed by the pitch feed in the Y-axis direction. If done, Workpiece 1
The contact direction between the and the grindstone 3 changes as shown in FIG. 8 as it moves from the center of the processed curved surface 2 in the Y-axis direction to the end side.

That is, when the grindstone 3 is at the position shown by the chain double-dashed line in FIG. 8 with respect to the workpiece 1, the contact direction (contact point P1) between the workpiece 1 and the grindstone 3 is the grindstone cutting feed direction (Z-axis). Direction) and is maintained in the normal direction of the curved surface 2, but when the grindstone 3 reaches the position shown by the solid line in FIG. 8, the contact direction (contact point P2) between the workpiece 1 and the grindstone 3 is the grindstone cutting feed direction. The angle θ1 deviates from the normal line 4 of the curved surface 2 that coincides with. As a result, a deviation corresponding to θ1 occurs between the machining position of the curved surface controlled by the NC shape data of the curved surface and the actual machining position, which adversely affects the accuracy of generating the curved surface.
Further, in the case of curved surface machining, when the grindstone 3 is cut and fed in the Z axis direction while moving the workpiece 1 in the X axis direction,
The contact direction between the grinding wheel 3 and the grindstone 3 changes as shown in FIG. 9 as it moves from the center of the processing curved surface 2 in the X-axis direction to the end side.

That is, when the grindstone 3 is at the position shown by the two-dot chain line in FIG. 9 with respect to the workpiece 1, the contact direction between the workpiece 1 and the grindstone 3 (contact point P3) is the grindstone cutting direction (Z-axis direction). ) Is maintained in the normal direction of the curved surface 2, but when the grindstone 3 reaches the position shown by the solid line in FIG.
The contact direction (contact point P4) with the deviation from the normal line 5 of the curved surface 2 that coincides with the grindstone cutting feed direction is deviated by an angle θ2. As a result, a deviation corresponding to θ2 occurs between the machining position of the curved surface controlled by the NC shape data of the curved surface and the actual machining position, which adversely affects the creation accuracy of the curved surface and causes the grindstone to wear. Then, the influence on the creation accuracy cannot be ignored, and it may not be possible to use it for mold forming for the toroidal mirror.

The present invention has been made in view of the above points, and provides a curved surface processing method capable of improving the accuracy of creation of a curved surface shape of a workpiece by maintaining a constant contact direction between the workpiece and a grindstone. To aim.

[0008]

In order to achieve the above object, the present invention is a curved surface machining method for machining a three-dimensional free curved surface on a workpiece by means of a grindstone. A grindstone head having a disk-shaped grindstone to be driven, a first driving means for relatively moving the support portion and the grindstone head in a cutting direction in which the workpiece and the grinding wheel come into contact with and separate from each other, and a driving direction perpendicular to the cutting direction. Second driving means for relatively moving the support portion and the grindstone head in the traverse feed direction, and third driving means for relatively moving the support portion and the grindstone head in the pitch feed feed direction perpendicular to the traverse feed direction.
Drive means, a fourth driving means for swinging the support portion or the grindstone head about an axis parallel to the traverse feed direction, and the support portion or the grindstone head about an axis parallel to the pitch feed feed direction. A fifth drive means for rocking the support part and the grindstone head are relatively pitch-feeded by the third drive means, and the contact direction between the workpiece and the grindstone is changed every pitch-feeding. A first step of swinging the support portion or the grindstone head by the fourth driving means so as to match the direction of the grindstone head; and a supporting portion by the second driving means after the first step. While the grindstone head is relatively moved in the traverse feed direction, the support portion and the grindstone head are relatively moved by the first drive means to give a cut to the grindstone, and at the same time, to the cut feed position. And a second step of machining the workpiece by swinging the support portion or the grindstone head by the fifth driving means so that the contact direction between the workpiece and the grindstone matches the direction of the grindstone head. I made it up.

[0009]

In the present invention, each time the rocking table and the grindstone head are relatively pitch-fed, the rocking table is rocked about an axis parallel to the traverse feed direction in accordance with the curved surface shape data, and the rocking table is moved. And the whetstone head are relatively moved in the traverse feed direction, the wobble table and the whetstone head are relatively moved in the cutting feed direction, and at the same time, the wobble table is moved around the axis parallel to the pitch feed feed direction in accordance with the curved surface shape data. By rocking
Even if the normal line of the free-form surface changes as the free-form surface of the workpiece is machined, the relation between the normal line of the free-form surface and the grindstone head can always be kept the same. Therefore, the precision of creating the curved surface of the workpiece can be improved.

[0010]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is a front view showing a cutaway part of a 5-axis control curved surface processing machine to which the method of the present invention is applied, and FIG. 2 is a left side view thereof. In FIG. 1 and FIG. 2, 10 is a bed installed on the floor surface 11 via a vibration isolation table 12, and 13 is a bed 10.
A slide table installed on the guide member 14 so as to be movable in the X-axis direction (traverse feed direction). The slide table 13 includes a ball screw 15 provided on the bed 10 side and a servo motor for rotationally driving the ball screw 15. It is configured to be moved in the X-axis direction by 16.

Reference numeral 17 denotes a first swing table provided on the slide table 13. The first swing table 17 is a support member on the slide table 13 by a support shaft 18 parallel to the X-axis direction. It is supported by 19 so as to be swingable around the A axis. The first drive mechanism 20 for swinging the first swing table 17 about the A axis is installed on the slide table 13 by the support member 21.

The first drive mechanism 20 comprises a ball screw 201 installed vertically and a servo motor 202 for rotating the ball screw 201.
The first nut member 203 is connected to the first swing table 17.

Reference numeral 22 is a second swing table supported on the first swing table 17 by a support shaft 23 so as to be swingable around a B axis orthogonal to the A axis. The second drive mechanism 24 for swinging the shaft around the B-axis is supported on the first swing table 17 by the support member 25.

The second drive mechanism 24 comprises a ball screw 241 arranged vertically and a servo motor 242 for rotating the ball screw 241.
The first nut 243 is connected to the second swing table 22. In addition, 1 is a workpiece set on the second swing table 22.

1 and 2, reference numeral 26 denotes a gate-shaped column fixedly mounted on the bed 10, and a grindstone mount 27 is provided on a horizontal portion 26a of the column 26 by a guide portion 28 in the Y-axis direction (pitch feed feed). The whetstone mount 27 is mounted on the column horizontal portion 26a in parallel with the Y-axis direction, and a servomotor 30 that rotationally drives the ball screw 29 causes the whetstone mount 27 to move in the Y-axis direction. It is configured to be moved to.

An elevating member 31 is mounted on the grindstone mount 27.
It is provided so as to be slidable in the axial direction (cutting feed direction), and at the lower end of this elevating member 31, a disk-shaped grindstone 32 having a ground surface in an arc and an electric motor 33 for rotationally driving the grindstone 32 are integrated. A grindstone head 34 is attached.

On the grindstone mount 27, a lifting member 31 is installed.
A servo motor 35 is installed so as to oppose to each other, and the upper end of the servo motor 35 and the elevating member 31 are connected by a ball screw (not shown). By rotating the ball screw by the servo motor 35, the elevating member 31 is moved. The included grindstone head 34 is configured to move in the Y-axis direction.

Next, the configuration of the control unit to which the method of the present invention is applied will be described with reference to FIG. In FIG. 3, a numerical controller 40 for controlling the processing machine on five axes includes a central processing unit (hereinafter abbreviated as CPU) 41 for controlling and managing the entire processing machine,
Memory 42 for storing programs and data, CPU
Drive pulse in accordance with the command from the X-axis, Y-axis, Z
A pulse distribution circuit 43 for distributing and supplying each servo motor for the axis, the A axis and the B axis is provided.

In the pulse distribution circuit 43, a slide table driving (X-axis) servomotor 16, a grindstone mount driving (Y-axis) servomotor 30, and a grindstone feed are provided via separate driving circuits 44 to 46. Servo motor 35 (for Z axis)
Are connected respectively. Furthermore, the pulse distribution circuit 4
3, a first swing table driving (for A axis) servo motor 202 and a second swing table driving (for B axis) servo motor 242 are separately driven via drive circuits 47 and 48.
Are connected respectively. As shown in FIG. 1, the memory 42 stores NC shape data (x, y, z, α, β) of the workpiece input from the input device 49, a machining program, and the like.

In the configuration of the above embodiment, the servo motor 16 is the second drive means, the servo motor 30 is the third drive means, the servo motor 35 is the first drive means, and the first drive means is the first drive means.
Drive mechanism (servo motor 202) 20 of the fourth drive means, the second drive mechanism (servo motor 242) 24 of the fifth drive means, and the first and second rocking table support portions. Configure.

Next, the curved surface processing operation of the present embodiment configured as described above will be described. When the workpiece 1 is curved, the pulse distribution circuit 43 is provided by giving a drive command from the CPU 41 to the pulse distribution circuit 43 according to the machining program of the memory 42 and NC shape data (x, y, z, α, β). The servo motor 16 is driven by the drive pulse sent from the swing table 17, 22.
While moving the slide table 13 including the X axis direction, the servo motor 30 is driven by the drive pulse from the pulse distribution circuit 43 based on the NC shape data and the machining program.
Is driven to move the grindstone head 34 including the grindstone mount 27 in the Z-axis direction, and at the same time, the second swing table 22 is swung about the B-axis by controlling the drive of the servomotor 242. One-pass machining of the workpiece 1 in the X-axis direction.

At this time, as shown in FIG. 4, the second rocking table 22 is rocked as the grindstone 32 for the workpiece 1 is moved from the position shown by the solid line to the position shown by the chain double-dashed line. Since the workpiece 1 is also swung around the B axis from the state shown by the solid line in FIG. 4 to the state shown by the two-dot chain line, the contact direction between the workpiece 1 and the grindstone 32 is the grindstone cutting direction (Z axis direction). Maintained. As a result, unlike the conventional case, the contact direction between the workpiece 1 and the grindstone 32 does not deviate from the grindstone cutting direction, and can always be kept in a matched state.

When the one-pass machining for the workpiece 1 is completed, the CPU is processed according to the machining program and the NC shape data.
By giving a drive command to the pulse distribution circuit 43 from 41, the servo motor 30 is driven by the drive pulse sent from the pulse distribution circuit 43, and the grindstone head 34 including the grindstone mount 27 is moved by one pitch in the Y-axis direction. Further, the servo motor 202 is driven by the drive pulse sent from the pulse distribution circuit 43 based on the NC shape data to swing the first swing table 17 around the A axis by a predetermined angle.

In this case, the Y of the grindstone 32 for the workpiece 1
As the axial pitch feed feed position is moved from the position indicated by the solid line to the position indicated by the two-dot chain line as shown in FIG. 5, the workpiece 1 is changed from the state shown by the solid line in FIG. Since the workpiece 1 and the grindstone 32 are swung, the contact direction between the workpiece 1 and the grindstone 32 is maintained in the grindstone cutting direction (Z-axis direction). As a result, unlike the conventional case, the contact direction between the workpiece 1 and the grindstone 32 does not deviate from the grindstone cutting direction, and can always be kept in a matched state.

After the 1-pitch feed of the grindstone head 34 in the Y-axis direction is completed, the X-, Z-, and B-axis control is performed again to machine the workpiece 1 in one pass. Hereinafter, by repeating the same operation, the entire surface of the workpiece 1 is machined into a curved surface corresponding to the NC shape data. FIG. 6 schematically shows a state of the series of curved surface processing described above.

In this embodiment as described above, the work piece 1 and the slide table 13 including the swing tables 17 and 22 are moved in the X-axis direction, while the grindstone head 34 including the grindstone mount 27 is moved in the Z-axis direction. Cutting feed, second at the same time
The oscillating table 22 is oscillated around the B axis to machine the workpiece 1 in one pass, the grindstone head 34 is moved in the Y axis direction by one pitch, and the first oscillating table 17 is moved around the A axis. Since the one-pass machining is performed again after swinging by a predetermined angle, as shown in FIGS. 4 and 5, the machining curved surface 2 in which the contact direction of the workpiece 1 with the grindstone 32 coincides with the grindstone cutting feed direction. Can be maintained in the normal direction.

That is, the relationship between the normal F of the machined curved surface 2 and the direction of the grindstone head 34 at the point where the workpiece 1 and the grindstone 32 contact each other is always the same regardless of the change in the direction of the normal of the machined curved surface 2. Can be kept constant. Along with this, the creation accuracy of the curved shape of the workpiece 1 is improved.

In the above-mentioned embodiment, the swing table 1 is used.
Although an example in which 7, 22 are swung about the A axis and the B axis so that the contact direction between the workpiece 1 and the grindstone 32 and the direction of the grindstone head 34 coincide with each other, the grindstone head 34 is moved along the A axis and the B axis. It may be swung around, or the grindstone head 34 may be rotated around the B axis,
The swing tables 17 and 22 may be swung around the A axis, or vice versa. Further, the present invention is not limited to the configurations shown in the above embodiments, and various modifications can be made without departing from the scope of the claims.

[0029]

As described above, according to the present invention, every time the workpiece support portion and the grindstone head are relatively pitch-fed, the support portion or the grindstone head is swung about an axis parallel to the traverse feed direction. In this state, while moving the support part and the grindstone head relatively in the traverse feed direction, the support part and the grindstone head move relatively in the cutting feed direction, and at the same time, the support part or the grindstone head swings about the axis parallel to the pitch feed feed direction With this configuration, even if the normal line of the free-form surface changes as the free-form surface of the workpiece is machined, the relationship between the normal line of the free-form surface and the grindstone head can always be kept constant. That is, the contact direction between the workpiece and the grindstone can always be maintained in a state of being coincident with the grindstone cutting direction, whereby the accuracy of creating the curved surface shape of the workpiece can be improved.

[Brief description of drawings]

FIG. 1 is a front view of a notch of a processing machine to which the method of the present invention is applied.

FIG. 2 is a left side view of FIG.

FIG. 3 is a block diagram showing a configuration of a control unit according to the embodiment of the present invention.

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 a contact relationship between a workpiece and a grindstone in the present embodiment.

FIG. 6 is an explanatory view schematically showing a curved surface processing state in the present embodiment.

FIG. 7 is an explanatory view showing a processed state of a conventional workpiece having a toroidal curved surface.

FIG. 8 is an explanatory diagram showing a conventional contact relationship between a workpiece and a grindstone.

FIG. 9 is an explanatory diagram showing a conventional contact relationship between a workpiece and a grindstone.

[Explanation of symbols]

 13 slide table 16 servo motor (second drive means) 17 first swing table 20 first drive mechanism (fourth drive means) 22 second swing table 24 second drive mechanism (fifth drive mechanism) Driving means) 30 Servo motor (third driving means) 32 Grinding stone 33 Grinding stone head 35 Servo motor (first driving means) 40 Numerical control device

Claims (1)

[Claims] 1. A curved surface machining method for machining a three-dimensional free-form surface on a workpiece with a grindstone, comprising: a support portion for supporting the workpiece; a grindstone head having a disk-shaped grindstone that is rotationally driven; A first drive means for relatively moving the support portion and the grindstone head in a cutting direction in which the object and the grindstone contact and separate from each other; and a first moving means for relatively moving the support portion and the grindstone head in a traverse feeding direction perpendicular to the cutting direction. 2 driving means, a third driving means for relatively moving the supporting portion and the grindstone head in a pitch feed feeding direction perpendicular to the traverse feeding direction, and an axis parallel to the traverse feeding direction for the supporting portion or the grindstone head. A fourth drive means for swinging the support portion or the grindstone head, and a fifth drive means for swinging the support portion or the grindstone head about an axis parallel to the pitch feed feeding direction, The support means and the grindstone head are relatively pitch-fed by the driving means of No. 3, and the fourth drive is performed so that the contact direction between the workpiece and the grindstone coincides with the direction of the grindstone head every pitch-feeding. A first step of rocking the support part or the grindstone head by means, and a second driving means subsequent to the first step while relatively moving the support part and the grindstone head in the traverse feed direction, The first driving means relatively moves the support portion and the grindstone head to make a cut in the grindstone, and at the same time, the contact direction between the workpiece and the grindstone matches the direction of the grindstone head in accordance with the cut feed position. A second means for machining the workpiece by swinging the support part or the grindstone head by the driving means of No. 5
And a curved surface processing method.