JP7701404B2 - Seal surface processing method and machine tool - Google Patents

Description

The present invention relates to a method for polishing a seal surface of a workpiece using a polishing tool with a shaft, and to a machine tool .

When joining two components that require airtightness at the joining surface, such as a vacuum chamber used in semiconductor manufacturing equipment, PVD (Physical Vapor Deposition) equipment, CVD (Chemical Vapor Deposition) equipment, etc., and a pipe that applies a vacuum to the vacuum chamber, the joining surface between the two components is generally polished. However, by using a polishing tool such as a grindstone, streaks called cutter marks or grinding surface marks are inevitably formed on the above-mentioned joining surface along the movement direction of the polishing abrasive grains. These streaks are usually on the order of μm, and it is difficult to completely fill them with a sealing material such as an O-ring or gasket. For this reason, if a cutter mark exists in a direction that connects the inside and outside of the joining surface (hereinafter referred to as the leak direction), this cutter mark will cause a leak. In addition, if a leak is discovered after assembly of the vacuum chamber device, large-scale disassembly and reassembly are required, so before assembly, a visual inspection is performed to see if the cutter marks on the sealing surface are concentric, and if necessary, polishing is performed manually.

Patent Document 1 describes a processing method and processing device for polishing a joint surface so that cutter marks are not produced in the leak direction by moving a polishing tool that rotates around a rotation axis parallel to the joint surface, while making the direction of the rotation axis of the polishing tool perpendicular to the direction of relative feed, along the contour shape of the joint surface.

JP 2002-254278 A

The processing method and processing device of Patent Document 1 require a dedicated polishing tool, which increases the processing cost. Furthermore, the polishing tool of Patent Document 1 is a belt polishing tool that runs an abrasive belt between two pulleys, which means that it is not possible to polish narrow grooves that house O-rings or small-diameter seal surfaces.

The technical objective of the present invention is to solve the problems of the conventional technology, and it is an object of the present invention to provide a method and machine tool for processing a seal surface that can use an inexpensive general-purpose tool to polish so that cutter marks are not produced in the leak direction, and that can polish the bottom surface of a narrow groove or a small diameter seal surface so that cutter marks are not produced in the leak direction.

In order to achieve the above-mentioned object, there is provided a method for machining a seal surface in which a seal surface of a workpiece placed on a table of a machine tool is polished by a grinding tool with a shaft attached to a spindle of the machine tool, the method comprising the steps of: bringing a tip surface of the grinding tool into contact with the workpiece; revolving the grinding tool around the workpiece along a closed loop using one or both of a linear feed axis and a rotary feed axis which move the spindle and the table of the machine tool relative to the workpiece; and, while the grinding tool makes one revolution, rotating the grinding tool around its axis using the spindle of the machine tool in the same direction as the revolution, with a phase difference of a value within ±180° and having no common denominator with 360, when a circumferential angle with respect to the revolution is 360°.

Further, according to the present invention, there is provided a seal surface processing device for grinding the seal surface of a workpiece with a grinding tool having a shaft, the device comprising: a spindle to which the grinding tool is attached ; a table to which the workpiece is attached; a feed shaft device having one or both of a linear feed shaft and a rotary feed shaft for moving the spindle relative to the table; and a control device for controlling the rotation of the spindle and the feed shaft device;
The control device brings the tip surface of the shank polishing tool into contact with the workpiece, and revolves the shank polishing tool relative to the workpiece along a closed loop using one or both of the linear feed axis and the rotary feed axis , and while the shank polishing tool makes one revolution, the shank polishing tool rotates in the same direction as the revolution with a phase difference of no common denominator and within ±180° when a circumferential angle with respect to the revolution is 360°.

According to the present invention, the rotor is rotated with a phase difference of ±180° relative to the revolution, so even if an inexpensive grinding tool with a shaft is used, cutter marks are not formed in the leak direction, and it is possible to grind a uniform and good sealing surface. In addition, by using a grinding tool with a thin shaft, it is possible to grind even narrow sealing surfaces such as grooves that accommodate O-rings.

1 is a side view showing an example of a machine tool to which the present invention can be applied. FIG. 2 is a simplified block diagram of the control device of FIG. 1 . FIG. FIG. FIG. 1 is a cross-sectional view showing a vacuum chamber and a pipe equipped with a flange joined to the vacuum chamber, as an example of a workpiece to be machined by the machining method of the present invention. FIG. 6 is a front view of the flange of FIG. 5 . FIG. 6 is a partial plan view showing a portion of the side of the vacuum chamber of FIG. 5 . 1 is a schematic diagram for explaining a phase difference between revolution and rotation; 1 is a schematic diagram for explaining a phase difference between revolution and rotation; This is a photographic image of a seal surface polished with a shaft-mounted brush tool with a phase difference of 23°. 1 is a photographic image of a seal surface polished with a shaft-mounted brush tool with a phase difference of 0°. This is a photographic image of the seal surface polished with a brush tool with a shaft while rotating the main shaft 112 at high speed. 1 is a schematic diagram showing the trajectory of the polishing action point when the phase difference is 180° and one revolution is made. 1 is a schematic diagram showing a trajectory of a polishing action point when a polishing tool with a shaft is caused to revolve along an elliptical closed loop. 1 is a schematic diagram showing a trajectory of a polishing action point when a polishing tool with a shaft is caused to revolve along an elliptical closed loop. 1 is a schematic diagram showing the trajectory of the polishing action point when a polishing tool with a shaft is revolved along a substantially rectangular (rounded square) closed loop. FIG. 11 is a side view showing another example of a machine tool to which the present invention can be applied. FIG. 18 is a block diagram showing a control device for the machine tool in FIG. 17 .

Hereinafter, preferred embodiments of the present invention will be described with reference to the accompanying drawings.
Fig. 1 is a schematic side view showing an example of a machine tool to which the present invention can be applied. In Fig. 1, the machine tool 100 is a vertical machining center. In this embodiment, the machine tool 100 is a three-axis processing machine having three orthogonal feed axes (X-axis, Y-axis, and Z-axis).

The machine tool 100 is equipped with a bed 102 as a base that is fixed to the floor of a factory or the like. A column 104 is erected on the rear end side of the upper surface of the bed 102. An X-slider 106 is attached to the front of the column 104 so as to be capable of reciprocating in the X-axis direction, which is the horizontal left-right direction (the direction perpendicular to the paper surface in FIG. 1).

The column 104 is provided with a ball screw (not shown) extending in the X-axis direction and an X-axis servo motor Mx connected to one end of the ball screw as an X-axis feed device that drives the X-slider 106 back and forth, and a nut (not shown) that engages with the ball screw is attached to the X-slider 106. In addition, the column 104 is provided with an X-axis digital scale (not shown) to detect the position of the X-axis feed device.

The spindle head 114 is disposed in front of the X-slider 106 so that it can reciprocate in the vertical Z-axis direction. As a Z-axis feed device that drives the spindle head 114 to reciprocate, the X-slider 106 is provided with a ball screw (not shown) extending in the Z-axis direction and a Z-axis servo motor Mz connected to one end of the ball screw, and a nut (not shown) that engages with the ball screw is attached to the spindle head 114. In addition, a Z-axis digital scale (not shown) is provided on the X-slider 106 to detect the position of the Z-axis feed device.

The spindle head 114 supports the spindle 112 so that it can rotate around a rotation axis Os that extends vertically. The spindle head 114 is equipped with a spindle servo motor Ms for driving the rotation of the spindle 112, and a rotary encoder (not shown) for detecting the rotational position and rotational speed of the spindle 112 around the rotation axis Os.

A tool T is removably attached to the tip of the spindle 112. In FIG. 1, the tool T is attached to the tip of the spindle 112 via a tool holder 116. The machine tool 100 can be equipped with a tool magazine (not shown) that stores a plurality of tools T, and an automatic tool changer (not shown) that exchanges tools T between the tool magazine and the spindle 112.

A table 108 is provided at the front end side (left side in FIG. 1) of the bed 102. The table 108 is designed to fix the workpiece W to be machined on the upper surface facing the spindle 112. The table 108 is mounted on a Y-slider 110 that can move in the Y-axis direction, which is the horizontal front-back direction perpendicular to the X-axis. As a Y-axis feed device that drives the Y-slider 110 back and forth, the bed 102 is provided with a ball screw (not shown) extending in the Y-axis direction and a Y-axis servo motor My connected to one end of the ball screw, and a nut (not shown) that engages with the ball screw is attached to the Y-slider 110. In addition, a Y-axis digital scale (not shown) is provided on the bed 102 to detect the position of the Y-axis feed device.

A rotary cutting tool (not shown) such as an end mill or drill can be attached to the tip of the spindle 112 as the tool T, but in the present invention, a shank-mounted polishing tool is particularly used as the tool T. The shank-mounted polishing tool has a shaft portion that extends along the central axis and a polishing portion provided at one end of the shaft portion.

Referring to FIG. 3, a brush tool with shaft is shown as an example of the shaft-mounted polishing tool used in the present invention. The brush tool with shaft 300 includes a shaft portion 302 extending along the central axis Ot, and a number of brushes 304 extending approximately parallel to the central axis Ot as polishing action parts provided at the tip of the shaft portion 302. The brushes 304 are held by a holder 306 provided at the tip of the shaft portion 302 so as to have a generally cylindrical shape as a whole. The brushes 304 protrude from the holder 306 by the same length so that the tip of each brush 304 is disposed in a plane Pe perpendicular to the central axis Ot, and the tips of the brushes 304 as a group form the tip surface of the brush tool with shaft 300. In this example, the tip of each brush 304 provides the polishing action point of the brush tool with shaft. Here, the material of the brushes 304 can be nylon with abrasive grains, ceramic wire, metal wire, natural hair, etc.

Referring to FIG. 4, a mounted grindstone is shown as another example of a mounted grindstone. The mounted grindstone 310 has a shaft 312 extending along the central axis Ot, and a grindstone 314 as a grinding part provided at the tip of the shaft 312. The grindstone 314 can be formed by bonding abrasive grains with a molding agent and forming them into a cylindrical shape. The grindstone 314 has a tip surface perpendicular to the central axis Ot. In other words, the abrasive grains on the end surface of the grindstone 314 are arranged in a plane Pe perpendicular to the central axis Ot, providing a grinding point for the mounted grindstone.

Next, the workpiece W to be machined according to the present invention will be described.
5 to 7, as an example of a workpiece W to be processed by the present invention, a joint between a vacuum chamber used in, for example, a semiconductor manufacturing apparatus, a PVD apparatus, a CVD apparatus, etc., and a pipe for applying a vacuum to the vacuum chamber is shown.

In Figures 5 to 7, the pipe 208 is joined to the side wall 220 by a flange 200. The side wall 220 may be one of the side walls forming the vacuum chamber. The side wall 220 is formed with a port hole 222. The port hole 222 may be a circular or cylindrical hole centered on the axis O. The side wall 220 is formed with a plurality of bolt holes 224 with internal threads. In this embodiment, four bolt holes 224 are arranged at equal angular intervals centered on the axis O.

The pipe 208 is joined to the side wall 220 by the flange 200. The flange 200 has a central opening 202 and a number of through holes 210. In this embodiment, the central opening 202 is circular and centered on the axis O, and four through holes 210 are arranged at equal angular intervals around the axis O. The pipe 208 is joined to the flange 200 by a known joining method such as welding so as to be coaxial with the central opening 202. The flange 200 is joined to the side wall 220 by passing bolts 212 through the four through holes 210 and screwing the bolts 212 into the bolt holes 224. When the flange 200 is joined to the side wall 220, the pipe 208, the central opening 202, and the port holes 222 are coaxial with respect to the common axis O.

In the flange 200, a groove 204 for receiving a seal member is formed on the surface facing and contacting the side wall 220. In this embodiment, a circular groove 204 is formed centered on the axis O, and an O-ring 206 is accommodated in the groove 204 as a seal member. When the flange 200 is joined to the side wall 220, the O-ring 206 in the groove 204 contacts the bottom surface 204a of the groove 204 and the surface portion 220a of the side wall 220 facing the bottom surface 204a. Therefore, in order to maintain a high degree of vacuum in the vacuum chamber, it is necessary to prevent leakage from between the O-ring 206 and the bottom surface 204a and the surface portion 220a. For this purpose, the seal surface with which the seal member comes into contact, in this embodiment the bottom surface 204a and the surface portion 220a, are polished by a shaft-mounted polishing tool T as described later.

Referring to FIG. 1, the machine tool 100 further includes a control device 10 for controlling the machine tool 100. The control device 10 can include an NC device for controlling the servo motors Mx, My, Mz of each of the feed devices for the three orthogonal axes of the X-axis, Y-axis, and Z-axis, and the servo motor Ms of the spindle 112, as well as a machine control device for controlling auxiliary equipment of the machine tool, such as a tool magazine (not shown) of the machine tool 100, an automatic tool changer (not shown), a machining fluid supply device (not shown), an oil/air supply device (not shown), and a compressed air supply device (not shown).

Referring to FIG. 2, the control device 10 has a numerical control unit 12 and a rotation control unit 14 as main components. The numerical control unit 12 can be configured with a general NC device. The rotation control unit 14 can be configured with a computer and related software including a CPU (central processing element), a memory device such as a RAM (random access memory) or a ROM (read only memory), a storage device such as a HDD (hard disk drive) or an SSD (solid state drive), input/output ports, and a bidirectional bus that interconnects these. The rotation control unit 14 can be configured as software as part of the NC device or machine control device.

The numerical control unit 12 controls the X-axis, Y-axis, and Z-axis feed devices and each servo motor 26 (Mx, My, Mz, Ms) of the spindle 112 based on the NC program 22 input by the operator or received from the CAM (not shown) and the coordinate values detected by the digital scales of the X-axis, Y-axis, and Z-axis and the rotary encoder of the spindle servo motor Ms, to move the table 108 and the spindle head 114 relative to each other and machine the workpiece W with the tool T.

The rotation control unit 14 includes a tool position calculation unit 16, a phase difference memory unit 18, and a spindle rotation angle calculation unit 20. The tool position calculation unit 16 receives the current position coordinates of the tool T from the numerical control unit 12. The current position coordinates of the tool T can be a position command generated within the numerical control unit 12 according to an NC program. Alternatively, the current position coordinates of the tool T may be generated based on the readings of the digital scales of the X-axis, Y-axis, and Z-axis.

Then, the tool position calculation unit 16 converts the position coordinates of the tool T into polar coordinates related to the axis O of the closed loop shape of the seal surface to be machined, and calculates the revolution angle θ of the tool T around the axis O. In the present invention, since the seal surface to be machined is a flat surface, the polar coordinates have the intersection point of the axis O and a plane perpendicular to the axis O that includes the seal surface as the pole, and include one radial coordinate and one angular coordinate. The revolution angle θ of the tool T around the axis O is given by one angular coordinate of the polar coordinates thus obtained.

The phase difference memory unit 18 stores the phase difference Δφ (FIG. 9) input by the operator from the phase difference input unit 24. The phase difference input unit 24 can be, for example, a touch panel (not shown) or a keyboard (not shown) provided on the operation panel (not shown) of the machine tool 100. The phase difference is the difference between the revolution angle (rotation angle of revolution) θ and the rotation angle (rotation angle of rotation) φ (FIGS. 6 and 7) of the tool T. In the present invention, the revolution is the relative rotation of the tool T with respect to the workpiece W around the axis O, which is the center of the seal surfaces 204a, 220a to be machined, and is generated by simultaneous two-axis control of the X-axis and Y-axis, and the rotation is the rotation around the rotation axis Os of the spindle 112.

The spindle rotation angle calculation unit 20 calculates the rotation angle φ of the spindle 112 in accordance with the following formula, based on the current revolution angle θ of the tool T received from the tool position calculation unit 16 and the phase difference Δφ received from the phase difference storage unit 18. The rotation angle φ of the spindle 112 calculated by the spindle rotation angle calculation unit 20 is input to the numerical control unit 12 as a position command for the servo motor Ms of the spindle 112.
φ=θ−Δφ×N×θ/360…(1)
Where:
φ: Rotation angle of the main shaft (degrees)
θ: Tool revolution angle (degrees)
Δφ: Phase difference (degrees)
N: The number of revolutions of the tool T.

In addition, in formula (1), -Δφ means that the phase difference is set so that the rotational motion lags behind the revolution motion. By making the rotational motion lag behind the revolution motion, it becomes easier to remove the machining waste generated during machining.

Referring to Figures 8 and 9, in which the rotation angle of the spindle 112 is indicated by an arrow, when Δφ=0°, that is, when there is no phase difference between the revolution motion and the rotation motion (the rotation angle φ of the spindle 112 is equal to the revolution angle θ of the tool T), when the tool T moves from rotation position T0 (θ=0°) in a counterclockwise direction around the axis O through rotation positions T1 (θ=90°), T2 (θ=180°), and T3 (θ=270°) and returns to rotation position T0 (θ=360°=0°), it will be understood that the spindle 112 returns to its original rotation angle (φ=0°) as shown in Figure 8.

In contrast, if a phase difference Δφ is provided between the revolution motion and the rotation motion, when the tool T moves from rotation position T0 (θ=0°) in a counterclockwise direction around the axis O through rotation positions T1 (θ=90°), T2 (θ=180°), and T3 (θ=270°) and returns to rotation position T0 (θ=360°=0°), it will be understood that the rotation angle of the tool T is φ=360°-Δφ as shown in FIG. 9. When the tool T makes two revolutions around the axis O, φ=360°-(2×Δφ). When the tool T revolves N times around the axis O, the rotation angle of the spindle 112 is φ=360°-(N×Δφ).

Next, the effects of this embodiment will be described with reference to Figures 10 to 12. Figures 10 to 12 are photographic images of the seal surface of a flat surface such as the side wall 220 that has been polished with a shaft-mounted brush tool 300. Figure 10 shows the phase difference Δφ = 23°, Figure 11 shows Δφ = 0°, and Figure 12 shows the seal surface when the main shaft 112 is rotated at high speed of approximately several hundred rpm.

According to this embodiment, as shown in FIG. 10, the cutter marks formed by the abrasive grains on the tip of the brush 304 of the brush tool 300 or the tip surface of the grinding wheel 314 of the grindstone 310 grinding the surface portion 220a of the side wall 220 are not formed in the leak direction in which air leaks, i.e., roughly in the radial direction, and a uniform and good sealing surface without unevenness in the concentric direction is obtained.

In contrast, when no phase difference is applied, that is, when Δφ = 0°, as shown in Figure 11, no cutter marks are formed in the leak direction, but there is significant unevenness in the concentric direction, making it impossible to obtain a good sealing surface with uniform roughness. Furthermore, when polishing is performed by rotating the main shaft 112 at high speeds of approximately several hundred rpm, as shown in Figure 12, many cutter marks are formed in the leak direction, making it impossible to obtain a good sealing surface.

In the embodiment described above, the phase difference Δφ is set so that when the tool T returns to the rotation position T0 (θ = 360° = 0°), that is, when the tool T has completed one revolution, the rotation angle becomes smaller than the rotation angle at the start of the revolution. However, the phase difference Δφ may be set so that the rotation angle becomes larger when the tool T has completed one revolution. In other words, in formula (1), Δφ may be a negative value.

In the embodiment described above, the phase difference was Δφ=23°, but the present invention is not limited to this, and other values of phase difference, -180°≦Δφ≦180°, may be set. FIG. 13 shows the trajectory of the polishing action point when the revolution is performed once with the phase difference being 180°. In this case, the trajectory passes all the way from the inner contact point of the outer edge of the seal area shown by the dashed line to the inner contact point of the inner edge. Therefore, if the phase difference is set to more than this, a cutter mark will be formed in the leak direction, so the upper limit of the phase difference is set to ±180°. If the phase difference has a common divisor with 360°, which is the rotation angle of one revolution, the cutter mark formed on the polished seal surface will have periodicity (certain parts will be polished more strongly than other parts), so it is desirable that the phase difference Δφ does not have a common divisor with 360. In addition, according to the inventors' experiments, if a phase difference larger than ±60° is set, a cutter mark with a twill pattern may be formed on the polished seal surface. This is not preferable for the sealing surface of a vacuum device where a concentric cutter mark is required, and is deemed unacceptable by visual inspection before the actual performance is confirmed. Therefore, it is preferable to set the phase difference to -60°≦Δφ≦60°. Δφ=±23° shown in the above-mentioned embodiment is one of the preferable values. Δφ=±17°, ±19°, ±31°, ±35°, ±41°, etc. also give favorable results. It is desirable to perform the revolution rotations until the cumulative phase difference exceeds at least 360°. This is because the abrasive grains return to the starting point of polishing to obtain a polished surface without unevenness. For example, in the above-mentioned embodiment where the phase difference is Δφ=23°, the minimum number of rotations is 16, which results in a cumulative phase difference of 368°.

Here, the phase difference given to the rotation and revolution in the present invention will be particularly explained. Even if the tool is rotated at high speed, for example, 100 revolutions, i.e., 360°, by the spindle 112 while the tool is revolving around the contour shape of the seal surface, it can be considered that the processing was performed by giving a phase difference to the rotation and revolution. However, in this case, as shown in Figure 12, many cutter marks are generated in the leak direction, and a good seal surface cannot be obtained. The intention of the present invention is to give a phase difference within a maximum range of ±180° to the rotation and revolution so that the trajectory of the abrasive grains on the tip surface of the shaft brush tool 300 or the shaft grindstone 310 becomes spiral-shaped, and it should be noted that this is essentially different from performing the high-speed rotation as described above.

In addition, in the embodiment described above, the tool T revolves along a circular closed loop, but the present invention is not limited to this, and the tool T may revolve along a closed loop of another shape. Figure 14 shows the trajectory of the polishing action point when the tool T revolves along an elliptical closed loop combining two parallel line segments of equal length and two semicircles, Figure 15 shows the trajectory of the polishing action point when the tool T revolves along an elliptical closed loop, and Figure 16 shows the trajectory of the polishing action point when the tool T revolves along a substantially rectangular (rounded quadrangle) closed loop combining four line segments of the same length and four quadrants connecting the line segments. In this way, this processing method can be applied to a seal surface having an arbitrary shape of a closed loop contour.

In addition, in the embodiment described above, the bottom surface 204a and the surface portion 220a are polished using a polishing tool with a shaft having a diameter equal to the width of the groove 204, but a thinner polishing tool may be used and a predetermined width may be polished by changing the revolution radius and polishing multiple times.

Although not shown in the figure, if the closed loop is made up of a part of a circle and a straight line portion, revolution motion can be performed only in the circular part. In other words, the machining along the circular closed loop described above can be divided and then connected by linear motion.

In Figures 14 to 16, each closed loop has a center (two axes of symmetry), so the revolution angle θ of tool T can be determined with the center as the pole. If the closed loop has only one axis of symmetry, such as an egg or oval shape, or has no axis of symmetry, the revolution angle θ of tool T can be defined with the center of gravity of the shape as the pole.

In addition, in the embodiment described above, the spindle 112 of the tool T is revolved around the table 108 along a circular closed loop by two linear feed devices of the X and Y axes, but the present invention is not limited to this, and the tool T may be revolved around the workpiece W along a circular closed loop by rotating the table 108. Alternatively, a special mechanism for revolving the spindle together with the tool may be provided and used. Figure 17 shows another example of a machine tool to which the present invention can be applied. In Figure 17, the same components as those in Figure 1 are given the same reference numbers, and duplicate explanations will be omitted below.

In the machine tool 100 shown in FIG. 1, the table 108 is a non-rotating table mounted on the Y slider 110, but the machine tool 150 shown in FIG. 17 is equipped with a rotary table 152 mounted on the Y slider 110. In other words, the machine tool 150 is a four-axis processing machine. The rotary table 152 is rotatably mounted around a rotation axis Oc extending in the vertical direction, and is equipped with a C-axis servo motor Mc inside that rotates and drives the rotary table 152. The C-axis servo motor Mc can be equipped with a rotary encoder.

Figure 18 shows the control device 50 of the machine tool 150. The control device 50 has roughly the same configuration as the control device 10 shown in Figure 2, and in Figure 18, components similar to those in Figure 2 are given the same reference numbers, and duplicated explanations will be omitted below.

The rotation control unit 52 of the control device 50 in Fig. 18 is equipped with a phase difference memory unit 18 and a spindle rotation angle calculation unit 54. In a machine tool 150 equipped with a rotary table 152, the rotation angle of the rotary table 152 is described in the NC program, so the spindle rotation angle calculation unit 54 of the control device 50 receives the rotation angle of the rotary table 152 from the numerical control unit 12 as the revolution angle θ of the tool T, and calculates the rotation angle φ of the spindle 112 according to the above formula (1) based on the rotation angle θ and the phase difference Δφ received from the phase difference memory unit 18. The rotation angle φ of the spindle 112 calculated by the spindle rotation angle calculation unit 54 is input to the numerical control unit 12 as a position command for the servo motor Ms of the spindle 112. The numerical control unit 12 controls the X-axis, Y-axis, and Z-axis feed devices, the rotary table 152, and each servo motor 56 (Mx, My, Mz, Mc, Ms) of the spindle 112 based on the NC program 22 and the coordinate values detected by the digital scales of the X-axis, Y-axis, and Z-axis and the rotary encoder of the C-axis servo motor Mc.

Other configurations for imparting revolutionary motion to the tool T include a type in which the spindle head performs feed motion in three axial directions, X, Y, and Z, and a type in which the table performs feed motion in two axial directions, X and Y. Also, a special mechanism for revolving the spindle 112 together with the tool T may be provided in addition to the feed axes of the X, Y, and Z axes.

REFERENCE SIGNS LIST 10 Control device 12 Numerical control unit 14 Rotation control unit 16 Tool position calculation unit 18 Phase difference storage unit 20 Spindle rotation angle calculation unit 100 Machine tool 108 Table 112 Spindle 220a Sealing surface 300 Shaft-mounted brush tool 310 Shaft-mounted grindstone

Claims (4)

A method for processing a seal surface, in which a seal surface of a workpiece placed on a table of a machine tool is polished by a shaft-mounted polishing tool attached to a spindle of the machine tool, comprising:
While a tip surface of the shaft-mounted polishing tool is brought into contact with the workpiece, the shaft-mounted polishing tool is revolved along a closed loop relative to the workpiece using one or both of a linear feed axis and a rotary feed axis which move the spindle and the table of the machine tool relative to the workpiece;
a sealing surface machining method comprising: rotating the abrasive tool on its axis using the main shaft of the machine tool in the same direction as the revolution, with a phase difference of no common denominator with 360 and within ±180°, when the circumferential angle with respect to the revolution is 360°, while the abrasive tool makes one revolution. The processing method according to claim 1, wherein the phase difference is less than ±60°. The processing method according to claim 1, wherein the sealing surface is formed on the bottom surface of a groove that houses the sealing member and on a surface facing the bottom surface. In a seal surface processing device that grinds the seal surface of a workpiece with a grinding tool having a shaft,
A spindle to which the shaft-mounted polishing tool is attached ;
A table on which the workpiece is attached; and
a feed shaft device having one or both of a linear feed shaft and a rotary feed shaft for moving the main shaft relative to the table;
a control device that controls the rotation of the spindle and the feed shaft device,
The control device,
While a tip surface of the shaft-mounted polishing tool is brought into contact with the workpiece, the shaft-mounted polishing tool is revolved around the workpiece along a closed loop using one or both of the linear feed shaft and the rotary feed shaft ;
A machine tool having a sealing surface, characterized in that while the abrasive tool with a shaft makes one revolution, the abrasive tool with a shaft is rotated in the same direction as the revolution with a phase difference of a value having no common denominator with 360 within ±180°, when the circumferential angle with respect to the revolution is 360°.

Images