JPS63251158A - Method and device for mechanical processing of free curvature - Google Patents

Abstract

PURPOSE:To enhance the grinding efficiency and approaching characteristic by feeding a cylindrical tool in the perpendicular direction to the axis of tool relative to the work to be processed, and at the same time, putting the tangential plane to the periphery of cylindrical tool in one plane with the tangential plane to free curvature of the work. CONSTITUTION:Attitude control is made so that the tangential plane to the periphery of a cylindrical tool 16 is in one plane with the tangential plane to free curvature of a work to be processed W, while the tool 16 is given feed in perpendicular direction to the axis of the tool relative to the work. W. This maximizes the processing width in the perpendicular direction to the feed of the tool. Because the cylindrical outer surface is transcripted contactlessly or in a similar condition regardless of the radius of tool 1, the pick feed amount can be made large. This gives further a great processing ability because processing is made at the periphery where the circumferential speed of the tool 16 is maximum. In the feed direction of the tool 16, processing is practicable till the recessed curvature with a radius corresponding to the radius of the tool 16.

Description

DETAILED DESCRIPTION OF THE INVENTION <Industrial Application Field> The present invention relates to a method for performing machining such as grinding or cutting on a free-form surface of a workpiece, and an apparatus therefor.

<Prior Art> Today, so-called free-form surface processing is performed in order to obtain a desired three-dimensional shape. Although there is no established definition of a free-form surface, it is generally considered to be a "curved surface that is difficult to represent using continuous relationships in analytical geometry."

Japanese Unexamined Patent Publication No. 61-279460 describes a curved surface grinding device that rotates a cylindrical grindstone around its axis while
It has been disclosed that grinding is performed by controlling the three axes of y and z. This is suitable for grinding quadratic surfaces where the inclination of the tangential plane changes only in one direction, but because the attitude of the grinding wheel axis remains unchanged, the inclination of the tangential plane changes in two or more directions. (free-form surfaces in a practical sense) are difficult to grind.

Grinding of substantially free-form surfaces is described, for example, in Japanese Patent Application Laid-Open No. 61-279.
As disclosed in Japanese Patent No. 459, it is common to use a spherical grindstone. Grinding is performed by rotating the spherical grindstone around the vertical axis to perform three-axis control, or by adding one or more rotation axes to the three axes to change the attitude of the grindstone axis. So-called two-dimensional micro-grinding, which combines vertical axis rotation and horizontal axis rotation, is also known, but this can also be seen as a type of grinding using a spherical grindstone.

On the other hand, a disk grindstone is rotated around a vertical axis, and a free-form surface is ground using the disk surface.

In this case, grinding is performed by using a five-axis control device so that the disc grindstone can cope with the unevenness of the free-form surface, or by posture control (X, Y, Z + vector) using an articulated robot or the like.

<Problems to be Solved by the Invention> However, when a spherical grindstone is used, the grindstone and the processed surface come into point contact. Therefore, the adaptation to the curved surface is poor, and the 12th
In order to minimize the occurrence of grinding marks (residues left after grinding) as shown in the figure, it is necessary to reduce the bit feed amount, which has the disadvantage of poor grinding efficiency. Furthermore, the circumferential speed is also unstable.

On the other hand, when using a disc grindstone, surface contact occurs, but the 15th
As shown in the figure, 1. When grinding a concave curved surface, the outer peripheral edge of the grinding wheel tends to bite (interference) with the machined surface, and there is a drawback that the grindstone cannot easily reach the deepest part of the concave curved surface. Further, since the circumferential speed is different between the inner circumferential side and the outer circumferential side of the disc grindstone, the grinding ability is not uniform in the radial direction. Moreover, there is also the problem that the attitude control of the grinding wheel shaft is complicated.

In this way, when using a spherical grindstone, the approachability to concave curved surfaces (in other words, shape adaptability) is good, but the grinding efficiency is low, and when using the disc grindstone, the grinding efficiency is good, but the approachability to concave curved surfaces is low. Conventionally, it has been difficult to achieve both grinding efficiency and accessibility.

The present invention group (hereinafter simply referred to as inventions) was made with the direct purpose of solving such problems in free-form surface grinding. However, the application of this idea is not limited to grinding, but can also be applied to cutting.

Means for Solving the Problems〉 □First Invention□ The first invention is a method for performing machining such as grinding or cutting on a free-form surface of a workpiece, in which a cylindrical tool is rotated around its tool axis. In addition to machining a free-form surface on the outer circumferential surface, simultaneous control of four or more axes including the three-dimensional coordinate axes X, Y, and Z axes and at least one rotation axis allows the cylindrical tool to be attached to the workpiece. While feeding the cylindrical tool in a direction relatively perpendicular to the tool axis, the cylindrical tool is It is characterized by controlling posture.

(1) Second invention (1) The second invention relates to an apparatus for performing machining such as grinding or cutting on a free-form surface of a workpiece, and is an invention of an implementation apparatus suitable for carrying out the method according to the first invention. . Its features are: (1) a cylindrical tool that is attached to the machining head and rotated around its own tool axis to perform free-form machining on the outer peripheral surface; (2) the machining head is attached to the cylindrical tool; An apparatus main body having four or more control axes including three-dimensional coordinate axes X, Y, and Z axes and at least one rotation axis for the processing head, and each of the control axes is provided with a driving means; 3) By controlling these driving means simultaneously, the cylindrical tool is sent in a direction perpendicular to the tool axis relative to the workpiece, and the tangential plane to the outer peripheral surface of the cylindrical tool and the free-form surface of the workpiece are and multi-axis simultaneous control means for controlling the position and orientation of the processing head so that the tangential planes for the machining head are the same tangential plane as possible.

□Third Invention□ The third invention, like the second invention, relates to an apparatus for performing machining such as grinding or cutting on a free-form surface of a workpiece, and is particularly characterized in that a machining center is used. That is, (a) a 5-axis machining center whose control axes are the three-dimensional coordinate axes of the X, Y, and Z axes, as well as the first and second rotation axes; A machining center comprising a movable part main body serving as a control axis, and a machining rod main body connected to the movable part main body using the first and second rotation axes as control axes; A cylindrical tool that is rotated and performs machining on the outer peripheral surface while being fed relative to a workpiece in a direction orthogonal to the tool axis, a driving means for rotating the cylindrical tool, and the cylindrical tool. is attached to the machining head main body and constitutes a machining head together with the main body, and the cylindrical tool rotates about the first rotation axis within a plane including the tool axis. (C) a machining tool device which is capable of turning and is also capable of turning around the second turning axis which is parallel to the turning plane and perpendicular to the tool axis; By simultaneously controlling four axes of one rotation axis or five axes including the second rotation axis according to the NC program, the first rotation axis is kept parallel to the feeding direction, and the outer circumferential surface of the cylindrical tool is The present invention is characterized in that it includes a multi-axis simultaneous control means for controlling the attitude of the cylindrical tool so that the tangential plane to and the tangential plane to the free-form surface of the workpiece are as much as possible the same tangential plane.

Functions and Effects> First, what these method and device inventions have in common is that they can improve the efficiency of processing such as grinding, and improve the accessibility.

In other words, while giving the cylindrical tool a feed relative to the workpiece in a direction perpendicular to the tool axis, the cylindrical tool is fed so that the plane tangential to the outer peripheral surface of the cylindrical tool is equal to the plane tangential to the free-form surface of the workpiece. By controlling the posture, the machining width in the direction perpendicular to the tool feeding direction can always be maximized.

In conventional spherical surface machining, the tool shape is transferred to the free-form surface of the workpiece in a point contact state, which necessitates machining with a small pick amount, but with the present invention, the cylindrical surface can be machined regardless of the tool radius. Since the shape of the outer circumferential surface is transferred in line contact or in a state close to it, a considerably large amount of big feed can be achieved.

Furthermore, since machining is performed on the outer circumferential surface of the cylindrical tool where the circumferential speed is maximum, the machining capacity for grinding and the like is large. Because of this, improvement in processing efficiency is achieved.

In addition, in conventional machining using a tool disk surface such as a disc grindstone, there was a problem that the outer periphery of the tool interfered with the concave curved surface, making it difficult to apply to concave curved surfaces. It is possible to machine up to a concave curved surface with a radius of curvature corresponding to the radius of a cylindrical tool, and in the tool width direction perpendicular to the feed direction, in addition to controlling the tool posture, it is possible to select a tool shape close to a concave curved surface. This allows for a wide range of applications.

For this reason, the tool's accessibility to the concavely curved surface is improved.

Note that the term "cylindrical tool" is not limited to a tool whose outer peripheral surface is a perfect cylindrical surface, but also includes a tool having a predetermined curvature in the tool width direction.

In addition, when performing the above-mentioned machining, we use a machining center that has the function of simultaneous multi-axis control, and unlike a normal machining head body, we use a dedicated machining center that does not have a spindle or a rotation transmission mechanism for driving the spindle. By using the machining head main body and the machining tool device attached to it, the tool axis can always be kept perpendicular to the feed direction even with rotation control. Equipment costs can be reduced compared to dedicated equipment.

<Example> Hereinafter, an example in which the present invention is applied to free-form surface grinding will be explained in detail based on the drawings. First, a detailed explanation of the device invention, and a detailed explanation of the method invention as well as its operation will be described. .

FIG. 1 shows an outline of a free-form surface grinding system with simultaneous four-axis control, and the core thereof is a five-axis machining center 10.

The 5-axis machining center 10 has a Y axis, which is a three-dimensional coordinate axis,
Three linear axes: the Y-axis and the Z-axis, the A-axis which is the first rotational axis parallel to the Y-axis (or the B-axis which is the rotational axis parallel to the Y-axis; however, the A-axis will be explained below), and the Z-axis. The control axes include a total of five axes, including the second rotation axis, the C axis, and the two rotation axes. This 5-axis machining center 10 uses three linear axes of x, y, and z as control axes to control the workpiece (work material) W.
A grinding head main body (hereinafter referred to as a 5-axis grinding head) 14 is connected to the movable part main body 12, with the two rotation axes of the A-axis and C-axis as control axes. ing. A grinding tool device 18 having a cylindrical grindstone 16 as a cylindrical tool is attached to the five-axis grinding head 14, and together with the five-axis grinding head 14, the grinding head is configured.

As shown in FIG. 2, the grinding tool device 18 includes a taber shank 22 attached to the movable body 12 of the machining center 10, and this shank 22 is integrated with the tool body 24. A movable tool base 26 is provided so as to be able to approach and separate from the tool body 24, and the base 26
A sliding rod 28 fixed to the tool body 24 is slidably fitted into a guide bush 30 fixed to the tool body 24, and a stopper 32 ensures a vertical movement stroke of, for example, lQn+. An air cylinder 34 is fixed to the tool body 24 as a grindstone biasing means, and its piston rod 36 is connected to the movable tool base 26 via a length-adjustable joint 38.

A grindstone drive motor 40 (for example, a high frequency motor) is fixed to the movable tool base 26 as a drive means. This motor 40 has an angled motor output shaft that is made perpendicular to the motor shaft by means of a direction changing means such as a bevel gear, and the cylindrical grindstone 16 is fixed to the output shaft, so that it can be rotated horizontally. has been done. The cylindrical grindstone 16 has a narrow flat cylindrical shape (also called a disk shape), and grinds the workpiece W on the outer circumferential surface of the cylinder by being rotated around the grindstone axis, which is the center line of the cylindrical grindstone 16. It is something. The air cylinder 34 presses the workpiece W against the free-form surface with a predetermined force.

The shank 22 of the grinding tool assembly 18 is secured in a tool mounting hole 44 formed in a tool mounting member 42 of the five-axis grinding head 14, as shown schematically in FIG. Tool mounting member 4
2 is supported by the grinding 5-axis head 14 of the 5-axis machining center 10 so as to be rotatable about the A-axis. Cylindrical grindstone 16
The axis of the grinding wheel is perpendicular to this A axis, and the cylindrical grinding wheel 1
6 includes its own grinding wheel axis and is rotatable around the A-axis within a plane perpendicular to the A-axis. The tool mounting member 42 is a worm wheel 46. Warm 48. Bevel gear 50.
52 and a subsequent gear train 54, etc., and are rotated by an A-axis servo motor. Furthermore, the grinding S-axis head 14 is supported by the movable part main body 12 of the five-axis machining center 10 so as to be rotatable around the C-axis. C
The axis is parallel to the Z axis and perpendicular to the A axis, and the cylindrical grindstone 1
6 can also rotate around this C-axis.

Note that the bearing in the figure is simply indicated as 56.

Such a five-axis grinding head 14 is unique to this embodiment, that is, it is a dedicated head for performing the free-form surface grinding of this embodiment. A typical head of the 5-axis machining center 10 is
This is a cutting head main body (hereinafter referred to as a 5-axis cutting head) 60 as shown in FIG. That is, the tool mounting member 42
A main shaft 62 having a tool mounting hole 44 is rotatably supported, and this main shaft 62 is rotated via bevel gears 64, 66, gear train 68, gears 70, 72, etc., and in this respect, the present embodiment is different. This is different from the grinding five-sleeve head 14. Dedicated grinding, not a general-purpose head 5
The reason for using the axial head 14 will be explained in detail later.

Returning to FIG. 1, the movable part main body 12 of the five-axis machining center 10 is provided with an air supply device 74 that supplies compressed air to the air cylinder 34 of the grinding tool device 18.

This air supply device 74 includes an electric valve 76 that opens and closes the air passage to the air cylinder 34, and an electromagnetic proportional pressure control valve 78 that controls the air pressure supplied to the air cylinder 34.
and an air supply controller 80. It is connected to an air pressure controller 82 and controlled by each electric signal. These controllers 8
0.82 constitutes a grinding condition controller 86 together with an inverter 84, and the inverter 84 is connected to the grindstone drive motor 40 and plays the role of controlling the rotation speed and starting/stopping of the motor 40.

As shown in FIG. 2, the tool body 24 of the grinding tool device I8 includes an air coupler 88 for supplying air to the air cylinder 34, and a receptacle 9 for supplying power to the motor 40.
0 is set. 91 is an air pipe. and,
Correspondingly, the tool mounting member 42 of the five-axis grinding head 14 shown in FIG. state.

As a result, an air passage is formed from the external compressed air source to the air cylinder 34 shown in FIG. 1, and an energizing path from the inverter 84 to the motor 40 is formed.

The grinding condition controller 86 is connected to a sequencer 96, and the sequencer 96 is connected to the 5-axis machining center 101.
It is connected to a machine operation panel 98 and an NC controller 100. The NC controller 100 is connected to each axis servo motor 104 via each axis servo unit 102 such as the X axis, Y axis, etc., and is also connected to an NC program input device 106.

Next, an embodiment of the grinding method will be described in conjunction with the explanation of the operation.

In this embodiment, the feeding direction of the cylindrical grindstone 16 relative to the workpiece W is set in advance in the X-axis direction, and among the five control axes of the five-axis machining center 10, the X-axis, Y-axis, and Z-axis are
Simultaneous control is performed on the four axes of the axis and the A-axis, and the cylindrical grindstone 16 rotating around the horizontal axis conforms to the free-form surface of the workpiece W, so that the width of the grinding by the cylindrical grindstone 16 in the direction orthogonal to the feed direction is always at its maximum. Make it so that

As a prerequisite for executing such simultaneous four-axis control, as shown in FIGS. 5 and 6, the C-axis is rotated so that the A-axis coincides with the feed direction (that is, the X-axis direction), The C-axis is fixed in its pivot position. As a result, the grindstone axis 0 of the cylindrical grindstone 16 is always kept perpendicular to the feeding direction.

In order to make the grindstone 16 conform to the free-form surface of the workpiece W, the grindstone is adjusted so that the plane tangential to the outer peripheral surface of the cylindrical grindstone 16 and the plane tangential to the free-form surface of the workpiece W are the same plane at the grinding site. Controls the position and posture of 16. In other words, the grindstone axis of the cylindrical grindstone 16 is made perpendicular to the normal line at the grinding point. The control concept for realizing this will be explained by projecting the curvature and inclination of the free-form surface of the workpiece W onto the XZ plane and the YZ plane based on FIGS. 5, 7, and 8.

Regarding the XZ plane, the X and Z axes are set so that the normal to the grinding point of the workpiece W projected onto the XZ plane intersects the grinding wheel axis at a distance corresponding to the radius of the cylindrical grinding wheel 16 from the grinding point. offset. On the other hand, regarding the YZ plane, the A-axis is rotated at a predetermined angle so that the normal line of the grinding point of the workpiece W projected onto the YZ plane is perpendicular to the grinding wheel axis at a distance corresponding to the radius of the grinding wheel 16 ( Strictly speaking, the tool mounting member 42 is rotated at a predetermined angle around the A axis), and the Y and Z axes are offset. Processing of the XZ plane as described above and YZ
In combination with the flat surface processing, simultaneous four-axis control is executed so that the cylindrical grindstone 16, which performs the grinding action on the outer peripheral surface, conforms to the curved surface of the workpiece W and the grinding width in the grindstone axis direction is maximized.

The process of creating an NC program for such simultaneous four-axis control will be explained based on FIG. 9 and FIG. 1θ.

In addition to the X, Y, and Z coordinates, the curved surface data of the workpiece W includes
Vector i indicating the normal at that point.

Including j and k. That is, the X-direction vector t, the Y-direction vector j, and the Z-direction vector, and it + j!
The relational expression 10kz = 1 holds true.

FIG. 10 shows the actual positional relationship of the grinding wheels, and FIG. 9 is a model of it. The contents of the symbols in each figure are as follows.

P: Grinding point 0: Grinding wheel axis (rotation center) MzA axis rotation center r grinding wheel radius l: Length of A-axis turning section AHA axis rotation angle Each of these coordinates is expressed as follows.

P(X, Y, Z) 0 (X+ir, Y+jr, Z+kr)Z + k r
+ -1), hego] 1] A = jan -' - (X direction feed) A = jan -
' - (Y-direction feeding) Although this embodiment assumes feeding in the X-axis direction, the above coordinates and turning angles are also shown for the case where the Y-axis direction is set as the feeding direction.

Using such data, the center of rotation of the grinding wheel is set to 0. Each coordinate of the A-axis rotation center M and the A-axis rotation angle A are determined, and an NC program for simultaneously controlling the machining center 10 on four axes is created. Also,
In addition to locus information for simultaneous four-axis control, the progera 1 contains information on grinding conditions such as the relative feed speed command of the grindstone 16, the number of rotations of the grindstone, and the pressing pressure. Opening/closing valve opening/closing information, tool information, etc. are included. Here, "tool information" refers to the tool information required when automatically replacing the grinding tool device 18.

Then, such NC program information is transferred to the NC program input device 106 shown in FIG. 1 via an NC tape or the like.
is supplied to the NC controller 100 from. The NC controller 100 supplies movement command information to each axis servo unit 102 so that each axis servo motor 104 operates according to the simultaneous four-axis trajectory information and feed rate command, and transfers other information to the sequencer 96.

The sequencer 96 receives and takes various information from the NC controller 100 and the machine operation panel 98, and sends commands corresponding to each to the 5-axis machining center 10 and the grinding condition controller 86.

The grinding condition controller 86 receives the following information from the sequencer 96. That is, an air pressure command for controlling the grindstone pressing pressure during grinding by instructing the air pressure of the air cylinder 34, and an air pressure command for instructing the opening/closing of the electromagnetic on-off valve 76 of the air supply device 74 to supply air to the air cylinder 34. It receives information such as valve opening/closing commands for controlling the grindstone drive motor 40 and motor commands for controlling the rotation speed and start/stop of the grindstone drive motor 40.

Based on these command information, the grinding condition controller 8
The air pressure controller 82 in the air supply device 6 sends an electric signal corresponding to the air pressure to the electromagnetic proportional pressure control valve 78 of the air supply device 74, and the air supply controller 80 sends a valve opening/closing signal to the electromagnetic opening/closing valve 76.

Based on this, the air supply device 74 supplies air at a predetermined pressure to the air cylinder 34. Further, the inverter 84 supplies the grindstone drive motor 40 with an alternating current having a frequency corresponding to the target rotation speed.

Under the grinding conditions given in this manner, the 5-axis machining center 10 to which the 5-axis grinding head 14 and the grinding tool device 18 are attached, performs the following operations based on the above-mentioned trajectory information, etc.
The cylindrical grindstone 16 rotates around the horizontal axis so that it conforms to the curved surface of the workpiece W, that is, the normal line at the grinding point projected onto the xz, yz plane is orthogonal to the grindstone axis.
Simultaneous 4-axis control is performed so that the grinding curved surface and the grinding surface share a common tangential plane.

Free-form surface grinding based on simultaneous four-wheel control using such a cylindrical grindstone 16 improves grinding efficiency and improves accessibility to concave curved surfaces, improving grinding efficiency and accessibility, which was difficult to achieve at the same time in the past. We were able to satisfy both requests.

For example, as shown in FIG. 12, a conventional spherical grindstone 20
0, the amount of pisok tweed must be reduced in order to reduce the amount of grinding residue, but according to experimental data, even if the flat part of the workpiece's free-form surface is ground with one fin bump, a grinding residue of 6 μm will remain. On the other hand, as shown in FIG. 13, in this embodiment, the cylindrical grindstone 16 has a grindstone width of, for example, 12 m.
Even if you use a grinder and roughen it to a roughness of 10 yen, there will be virtually no leftovers left after grinding. Furthermore, as shown in FIG. 14, even on a curved surface with a radius of curvature R of, for example, 1,500 mm, the remaining amount of grinding can be suppressed to about 8 μm with a similar rough bump.

Furthermore, as shown in FIG. 15, when attempting to grind a concave curved surface by rotating the conventional disk grindstone 202 on its vertical axis, interference occurs at the outer periphery of the disk grindstone 202.
Although it is difficult to apply to concave curved surfaces, in this example, the first
As shown in FIG. 6, in principle, in the feeding direction of the grindstone 16, it is possible to grind up to a concave curved surface with a radius of curvature corresponding to the radius of the grindstone r. Further, as for a concave curved surface in the width direction of the grindstone, by controlling the width of the grindstone and controlling the attitude of the grinding tool device 18 including the grindstone 16, the present invention can be applied to a concave curved surface with a considerably large curvature. Moreover, the shape of the outer peripheral surface of the cylindrical whetstone 16 is not a perfect cylindrical surface, but a cylindrical whetstone such as a whetstone with rounded ends in the width direction of the whetstone or a phase-shaped whetstone whose outer peripheral surface has a shape of curvature corresponding to a concave curved surface. If selected, the accessibility to the concave curved surface will be further improved.

In addition, even when grinding a convex curved surface on the disk surface of the disk grindstone 202, in addition to the three linear axes of Control is essential.

On the other hand, in this embodiment, the number of control axes is limited to one rotation, which allows for four-axis control, and therefore the control is simplified accordingly.

By the way, as previously explained with reference to FIGS. 3 and 4, the 5-axis grinding rad 14 mounted on the 5-axis machining center 10 includes the general 5-axis cutting rad 60 shown in FIG. There is no main shaft 62 to which the cutting tool is attached, gears 64, 66 for rotating the main shaft, gear train 68 following the main shaft 62, etc. seen in the above. This is due to the following reason.

If we were to attach the shank 22 of the grinding tool device 18 to the tool attachment hole 44 of the main shaft 62 of the 5-axis cutting head 60 to perform simultaneous 4-axis control, the A-axis containing the main shaft 62 and its gear train When the turning portion (tool mounting member 42) turns at a certain angle, the bevel gear 64 becomes a planetary gear and rotates around the bevel gear 66 while meshing with it, so that the main shaft 62 rotates with it. The rotation angle of the main shaft 62 relative to the A-axis rotation angle is determined by the gear ratio of the bevel gears 64 and 66 if the bevel gear 66 is in a fixed state, and if the gear ratio is 1, it is equal to the A-axis rotation angle. gear 6
When gear 64.6 is in a free state, gear 64.
If the torque distribution to 66 is the same, both gears 64.66
rotates by half of the A-axis rotation angle. Although the gears 64 and 66 are relatively shifted by the A-axis rotation angle, the apparent co-rotation of the gear 64 is the A-axis rotation angle/2.

The upper part of Fig. 11 shows the cutting 5 with the grinding tool device attached.
This figure compares the difference in movement of the 5-axis grinding head 60 and the 5-axis grinding head 14 with respect to A-axis rotation. Which head 6
0.14, the orientation of the grindstone 16 is set so that when the A-axis rotation angle is O'', the A-axis and the grindstone axis vAO are at right angles, and the grinding of this example is carried out by simultaneous 4-axis control. must maintain the orientation of the grindstone 16 with respect to the A-axis.

However, in the 5-axis cutting head 60, as a result of the rotation of the main shaft 62 accompanying the rotation of the A-axis, the axis of the grinding wheel cannot always be kept perpendicular to the A-axis and thus the feed direction, and Difficult to maintain maximum grinding width. This results in inconveniences such as residual grinding and digging. On the other hand, with the five-axis grinding head 14, the relationship between the grindstone 16 and the A-axis is maintained unchanged regardless of the A-axis rotation, and the desired grinding with four-axis simultaneous control can be achieved.

In this embodiment, it is assumed that the C-axis, which is the rotation axis, is fixed, but even when controlling including the rotation of this C-axis, the main axis 62 of the 5-axis cutting head 60 shown in FIG. Companionship occurs. In other words, when the cutting head 60 is rotated around the C-axis, the gear 70 becomes a planetary gear and rotates around it while rotating due to meshing with the gear 72, so that its rotation causes the gear train 68, etc. It is then transmitted to the main shaft 62 to cause rotation. Therefore, the first
As illustrated in the lower part of Fig. 1, the five-axis cutting head 60 cannot maintain a perpendicular relationship between the grinding wheel axis and the A-axis when the C-axis rotates, but according to the five-axis grinding head 14, No inconvenience will occur.

In any case, in the grinding system of this embodiment using the 5-axis machining center 10, the dedicated grinding 5-axis hand 14
By using the grinding tool device 18 and simultaneously controlling the four axes, the desired free-form surface grinding described above can be achieved.

In the embodiment described above, the feeding direction of the grindstone 16 is set along the X axis (
Although it is set in the A-axis direction, it is of course possible to set it in other directions such as the Y-axis direction.

Also, by rotating the C-axis without fixing it,
When the feed direction is changed from time to time, the control is extended to five-axis simultaneous control of three linear axes X, Y, and Z and two turning axes A and C.

In addition, the use of an existing 5-axis machining center has the economical advantage of lower equipment costs compared to using a dedicated grinding device, but it is not necessarily limited to this, and the use of a dedicated multi-axis simultaneous control NC grinding machine is not limited to this. You can also.

Furthermore, the present invention is not limited to grinding, but can also be applied to cutting of free-form surfaces using a rotating blade (for example, milling, etc.).

It goes without saying that the present invention can be implemented with various other modifications based on the knowledge of those skilled in the art.

[Brief explanation of drawings]

Fig. 1 is a schematic diagram of a free-form surface grinding system that is an embodiment of the present invention, Fig. 2 is a front view showing a section of a part of the grinding tool device, and Fig. 3 is a grinding machine to which the grinding tool device is installed. A schematic diagram of a 5-axis head. Figure 4 is a schematic diagram of a general 5-axis cutting head. Figure 5 is a diagram of the posture of the grinding wheel during grinding projected onto the basic coordinate plane. Figure 6 is the axis of the grinding wheel and feed. Figure 7 is a diagram showing the offset of coordinates on the XZ plane, which is a prerequisite for controlling the attitude of the grindstone, Figure 8 is a diagram showing the offset of coordinates on the YZ plane, and Figure 9 is a diagram showing the offset of the coordinates on the YZ plane. Figure 10 is a geometric model of the basic elements related to a grinding wheel. Figure 10 is a diagram applying the model to an actual device. Figure 11 is a diagram showing the case of using a general 5-axis cutting head and the case of using a dedicated grinding 5-axis head.
Figure 12 shows an example of grinding using a conventional spherical grinding wheel. FIG. 14 shows an example of grinding a flat part according to the present invention, FIG. 14 shows an example of grinding a curved surface, FIG. 15 shows an example of grinding a concave curved surface using a conventional disc grindstone, and FIG. It is a figure which shows the example of grinding of a curved surface. 10: 5-axis machining center 12: Movable part body 14: Grinding 5-axis head (grinding head body) 16: Cylindrical grindstone 18: Grinding tool device 34: Air cylinder (
(biasing means) 40: Grinding wheel drive motor (driving means) 42: Tool mounting member 60: Cutting 5-axis head 74: Air supply device

Claims (9)

[Claims] (1) In a method of performing machining such as grinding or cutting on a free-form surface of a workpiece, a cylindrical tool is rotated around the tool axis to machine the free-form surface on the outer circumferential surface, and a three-dimensional coordinate axis is used. By simultaneous multi-axis control of four or more axes including the X-axis, Y-axis, Z-axis, and at least one rotation axis, the cylindrical tool is fed relative to the workpiece in a direction perpendicular to the tool axis,
A free-form surface machine, characterized in that the attitude of the cylindrical tool is controlled so that a tangent plane to the outer peripheral surface of the cylindrical tool and a tangent plane to the free-form surface of the workpiece are as much as possible the same tangent plane. Processing method. (2) The feeding direction is set to one of the X-axis, Y-axis, and Z-axis, and the one rotation axis is parallel to the feeding direction, and the cylindrical tool is rotated around the rotation axis. 2. The method according to claim 1, wherein the attitude of the cylindrical tool is controlled by simultaneous four-axis control including turning the cylindrical tool within a plane including the tool axis. (3) The method according to claim 1 or 2, wherein the machining is grinding with a cylindrical grindstone. (4) A device that performs machining such as grinding or cutting on a free-form surface of a workpiece, which is attached to a processing head and rotated around its own tool axis, and performs machining of the free-form surface on the outer peripheral surface. a cylindrical tool; and the processing head is attached to the processing head, and the processing head has four or more control axes including three-dimensional coordinate axes, X-axis, Y-axis, Z-axis, and at least one rotation axis; The main body of the device is equipped with driving means for each control axis, and by controlling these driving means simultaneously, the cylindrical tool is sent relative to the workpiece in a direction perpendicular to the tool axis. and multi-axis simultaneous control means for controlling the position and orientation of the processing head so that a tangent plane to the outer peripheral surface of the workpiece and a tangent plane to the free-form surface of the workpiece are as much as possible the same tangent plane. Features free-form surface machining equipment. (5) The feeding direction is set in one of the X-axis, Y-axis, and Z-axis, and the one rotational axis is set parallel to the feeding direction, and the rotational axis is rotated around the rotational axis. 5. The machining apparatus according to claim 4, wherein the cylindrical tool is rotatable within a plane including its own tool axis, and the multi-axis simultaneous control means is a four-axis simultaneous control means. (6) The device according to claim 4 or 5, wherein the machining device is a grinding device equipped with a cylindrical grindstone. (7) A device that performs machining such as grinding or cutting on a free-form surface of a workpiece, and uses the three-dimensional coordinate axes of the X-axis, Y-axis, Z-axis, and the first and second rotation axes as control axes. The 5-axis machining center includes a movable part main body having three basic axes of X, Y, and Z as control axes, and a processing head connected to the movable part main body with the first and second rotation axes as control axes. a cylindrical tool that is rotated around its own tool axis and performs machining on the outer circumferential surface of a workpiece while being fed in a direction perpendicular to the tool axis relative to the workpiece; The cylindrical tool includes a driving means for rotating the cylindrical tool and a biasing means for pressing the cylindrical tool against the free-form surface, and is attached to the processing head main body to constitute a processing head together with the main body, and the cylindrical tool A processing tool device capable of rotating around the first rotation axis within a plane including the tool axis, and also rotating around the second rotation axis parallel to the rotation plane and perpendicular to the tool axis. , by simultaneously controlling the four axes of the X-axis, Y-axis, Z-axis, and first rotation axis, or the five axes including the second rotation axis according to an NC program, the first rotation axis is controlled in the feeding direction. A multi-axis control device that controls the attitude of the cylindrical tool so that the tangential plane to the outer circumferential surface of the cylindrical tool and the tangential plane to the free-form surface of the workpiece are as much as possible the same tangential plane while keeping the cylindrical tool parallel to the outer peripheral surface of the workpiece. A free-form surface machining device, characterized in that it includes simultaneous control means. (8) The feeding direction is set to one of the X-axis, Y-axis, and Z-axis, and the second rotation axis is fixed so that the first rotation axis is parallel to the feeding direction. The machining apparatus according to claim 7, wherein the multi-axis simultaneous control means performs four-axis simultaneous control of the X-axis, Y-axis, Z-axis, and the first rotation axis according to an NC program. . (9) The device according to claim 7 or 8, wherein the machining device is a grinding device equipped with a cylindrical grindstone.