JP5138352B2 - Processing method and processing apparatus - Google Patents

Description

  The present invention relates to a machining method and a machining apparatus for machining a machining surface of a workpiece with high accuracy using a tool.

Optical devices that require high precision and fine processing (for example, glass lenses with a small diameter and a large curvature, and fine groove shapes) as devices such as optical disk devices and optical communication devices become smaller and larger in capacity. Glass parts) are increasing rapidly.
Conventionally, optical parts formed from hard and brittle materials such as glass, single crystal silicon, and ceramics are finished by grinding or polishing. However, since the elastic deformation of the abrasive grains in contact with the machined surface affects the accuracy of the machined surface and clogging of the abrasive grains affects the machining efficiency, cutting is performed from the viewpoint of higher accuracy and higher efficiency. A processing method by processing has been attempted.

In order to cut hard brittle materials with high accuracy, it is necessary to cause ductile fracture instead of brittle fracture in the processed portion. In such machining (ductility mode machining), the depth of cut must always be kept below the “maximum critical depth of cut D”. The maximum critical depth of cut D indicates the depth of cut at the point where the fracture process transitions from brittle to ductile. The D value in a typical hard and brittle material is shown below.
Hard brittle material Maximum critical depth of cut (D)
BK7 (borosilicate glass) 25nm
Silicon 31nm-100nm
GE (Germanium) 50nm-60nm
Vitreous silica (quartz glass) 180nm
SiC (silicon carbide) 490nm
Thus, in ductile mode machining of hard and brittle materials, the higher the hardness, the smaller the D value. For example, due to fluctuations in the D value due to the motion accuracy of the processing machine, the ductile mode machining becomes unstable and the cutting tool is damaged. There is a possibility. There is a problem that conventional processing machines are not practical.

In order to solve such problems, a cutting method and a cutting apparatus disclosed in Patent Document 1 are known as a method and apparatus for processing a work surface of a workpiece with high accuracy.
The cutting device of Patent Document 1 includes a tool holder that holds a tool and has a facing surface that faces the processing surface. Further, the cutting device includes a swing support unit that swings the opposing surface of the tool holder in a direction approaching or separating from the processing surface, and a static pressure generation unit that generates a static pressure between the processing surface and the opposing surface. With.
Specifically, the static pressure generating means includes a supply device that supplies a cutting fluid between the machining surface and the facing surface, and a suction device that sucks the cutting fluid. And a static pressure is generated between the opposite surfaces. By generating the static pressure in this way, the interval between the processed surface and the facing surface becomes an interval according to the static pressure. At the time of cutting, the static pressure is set to a predetermined level or more, the cutting tool is brought into contact with the work surface of the workpiece, and the work surface can be cut with a constant cutting amount.

JP-A-9-262737 (FIGS. 1 and 2)

  In the cutting method and the cutting apparatus disclosed in Patent Document 1 described above, since a static pressure is generated between the machining surface and the opposing surface by sucking the cutting fluid, in order to maintain a stable static pressure The opposing surface that faces the processing surface is required to have a predetermined area or more. However, when the work surface of the workpiece is not a flat surface such as an aspheric lens, it is difficult to secure a facing surface having a predetermined area or more. In such a case, a stable static pressure cannot be obtained, and it becomes difficult to keep the cutting depth constant. In addition, when the cut chips are sucked together with the cutting fluid, the suction flow rate of the cutting fluid may fluctuate, so that the static pressure cannot be kept constant, and hard brittle materials may not be cut with high accuracy. is there.

  The object of the present invention is to solve such problems and to press the tool against the workpiece with a stable and constant pressing pressure, and is stable against hard and brittle materials that require a minute critical depth of cut. Another object of the present invention is to provide a processing method and a processing apparatus capable of performing the ductile mode processing.

The machining method of the present invention is a machining method for machining the workpiece by the tool while relatively moving the tool and the workpiece, and holding the tool and moving the tool in a direction of pressing and separating the workpiece. A movable member that can be moved, a support member that movably supports the movable member, a pressing pressure generating unit that generates a pressing pressure that presses the movable member in the pressing direction, and a pulling pressure that pulls the movable member in a direction that separates the movable member. A constant pressure mechanism having a generated pressure generation unit, and a constant pressure difference between the pressurized air supplied to the pressing pressure generation unit and the suction pressure generation unit, respectively, and the movable member to the workpiece with processed while pressing at a certain contact pressure, during this processing, the movable said displacement amount in the moving direction of the movable member detected by the displacement sensor, detected by the displacement sensor Evaluate the amount of displacement of the material to predict or detect the chatter of the tool, and adjust the pressure of the pressurized air supplied to the pressing pressure generation unit and the pulling pressure generation unit according to the prediction or detection result The pressing force against the workpiece is changed .

According to this configuration, the movable member is provided so as to be movable in the pressing and separating directions, and the movable member is processed while being pressed against the workpiece with a constant pressing pressure. It is moved in a direction approaching or separating from the workpiece. As a result, the cutting depth of the tool can be maintained at a constant amount regardless of the shape of the workpiece surface and the dynamic and static accuracy of the machining apparatus.
In particular, even for a hard and brittle material with a maximum critical cutting depth, the pressure difference between the pressurized air supplied to the pressing pressure generating section and the pulling pressure generating section is the pressure corresponding to the maximum critical cutting depth. By setting it below the difference, the cutting depth can always be within the allowable range.
Therefore, the tool can be pressed against the workpiece with a stable and constant pressing pressure, and stable ductile mode processing can be performed on a hard and brittle material that requires a minute critical depth of cut.
Even when the support rigidity of the tool is low, by monitoring the displacement amount of the movable member holding the tool with a displacement meter such as a laser displacement meter or a capacitance type displacement meter, Can be detected. Furthermore, chattering and the like can be prevented from occurring by changing the condition of the pressurized air supplied to the constant pressure mechanism according to the detected displacement amount.

In the processing method of the present invention, it is preferable to set a pressure difference between the pressurized air supplied to the pressing pressure generation unit and the pulling pressure generation unit according to a cutting amount of the tool with respect to the workpiece.
According to this configuration, it is possible to easily set the pressure difference corresponding to the cutting depth of the tool by simply changing the pressure of the pressurized air supplied to the pressing pressure generating unit and the pulling pressure generating unit, It is possible to improve the efficiency of the processing work.

The processing apparatus of the present invention includes a base, a work supporting means provided on the base for gripping the work, a tool for processing the work, and a constant pressure provided on the base to press the tool against the work with a constant pressing pressure. A machining device for machining the workpiece by the tool while relatively moving the tool and the workpiece, wherein the constant pressure mechanism holds the tool and presses the tool against the workpiece. And a movable member movable in the separating direction, a supporting member that movably supports the movable member, a pressing pressure generating portion that generates a pressing pressure that presses the movable member in the pressing direction, and the movable member is separated. A pressure generating unit that generates a pulling force that pulls in a direction, and supplies compressed air to each of the pressing pressure generating unit and the pulling pressure generating unit. And having, further, a displacement meter for detecting a displacement amount in the moving direction of the movable member performs foreseen or detection of chatter of the tool to evaluate the amount of displacement of the movable member detected by the displacement sensor, the A control device that adjusts the pressure of the pressurized air supplied to the pressing pressure generation unit and the pulling pressure generation unit according to the prediction or detection result to change the pressing force of the tool against the workpiece. It is characterized by.

  According to this configuration, the workpiece support means and the constant pressure mechanism are provided on the base, the movable member is provided so as to be movable in the pressing and separating direction, and the movable member is processed while being pressed against the workpiece with a constant pressing pressure. The tool is moved in a direction approaching or separating from the workpiece in accordance with the unevenness of the work surface of the workpiece. As a result, the cutting depth of the tool can be maintained at a constant amount regardless of the shape of the workpiece surface and the dynamic and static accuracy of the machining apparatus. Therefore, the processing described in the processing method can be realized by using this processing apparatus.

In the processing apparatus according to the present invention, the support member is provided with an air bearing at two positions sandwiching the pressing pressure generating portion and the pulling pressure generating portion, the movable member is pivotally supported by the air bearing, and the pressing It is preferable that the pressure generating part and the attractive pressure generating part communicate with outside air through the air bearing.
Here, in the case of conventional grinding, the contact area (working area) between the tool and the workpiece is larger than that of cutting, and the pressing pressure of the tool can be set large, so the support rigidity for supporting the tool is increased. There was a wide range of stable areas where chatter did not occur. On the other hand, for example, in a cutting process using a diamond cutting tool to which a single crystal diamond chip is bonded, it is necessary to set the pressing pressure of the tool to several tens mgf or less. For hard and brittle materials, in order to establish ductile mode cutting, the cutting depth of the tool must be set small, and the pressing pressure of the tool needs to be set small. For the reasons described above, there has been a problem that the support rigidity of the tool is lowered and chatter is likely to occur, or chatter is increased while minute vibrations generated intermittently develop due to the regenerative effect.

  On the other hand, according to the configuration of the present invention, when the movable member holding the tool moves in the pushing direction, the pressurized air of the pressing pressure generating portion and the pulling pressure generating portion consumes energy by the air of the air bearing. This energy consumption attenuates the movement of the movable member. Accordingly, chatter and the like generated in the movable member can be suppressed, and stable machining can be maintained.

Hereinafter, embodiments of the present invention will be described with reference to the drawings.
FIG. 1 is a front view showing a part of the processing apparatus according to the embodiment in cross section. In FIG. 1, the length direction (left-right direction in the figure) is the X axis, the width direction (direction orthogonal to the paper surface) is the Y axis, and the direction orthogonal to the upper surface of the base is the Z axis. The following explanation will be given.

<Overall configuration of processing equipment>
The processing apparatus is an apparatus for rotating the workpiece W and cutting the workpiece W with the tool T. The base 1 and the workpiece rotating mechanism 2 (work support) arranged in parallel in the X-axis direction on the upper surface of the base 1. Means) and a tool moving mechanism 3 (constant pressure mechanism), and a tool T attached to the tool moving mechanism 3. The processing apparatus also includes a compressed air path 5 (compressed air supply means) for supplying pressurized air from the compressor 4 to the tool moving mechanism 3 and a control device 6 for controlling the flow rate and pressure of the supplied pressurized air. Configured.

  The work rotation mechanism 2 is provided to rotate the work W around a P axis parallel to the X axis, and includes a substantially cylindrical main shaft 21 and a housing 22 that rotatably supports the main shaft 21. A workpiece W is detachably gripped on the P-axis at the tip of the main shaft 21. The main shaft 21 and the work W are rotated by means of rotation driving means such as an electric motor (motor), an air turbine, etc. (not shown). It is designed to rotate as a center.

  Between the base 1 and the tool movement mechanism 3, an X-axis drive mechanism 7 that moves the tool movement mechanism 3 in the X-axis direction and a Y-axis drive mechanism 8 that moves the tool movement mechanism 3 in the Y-axis direction are provided. It has been. As a result, the tool moving mechanism 3 can be moved relative to the base 1 in the X-axis and Y-axis directions orthogonal to each other. In addition, although the drive mechanisms 7 and 8 of each axis | shaft are comprised by the ball screw feed mechanism etc., it is not restricted to this.

  The tool T may be an end mill formed in a shape including a tip or a cutting edge, or may be a grindstone used for finishing a processed surface. A plurality of types of tools T having different shapes are prepared in advance, and the user can select an optimum tool according to the machining purpose and use it for machining. In this embodiment, a diamond tool having a single crystal diamond tip bonded to the tip is used as the tool T.

<Configuration of tool movement mechanism>
FIG. 2 is a sectional view showing the tool moving mechanism 3.
The tool moving mechanism 3 is a mechanism for pressing the tool T against the work W with a constant pressing pressure by moving the tool T along the direction in which the tool T is pressed against or separated from the work W, that is, along the X-axis direction. And a slider 31 having a tool T fixed to the tip, and a slider support member 32 that supports the slider 31 movably along the X-axis direction.

  The slider 31 has a substantially prismatic shape extending in the X-axis direction, a front slider 33 for fixing the tool T, a rear slider 34 provided on the opposite side of the tool T, and the front slider 33 and the rear slider at the center. And a connecting portion 35 for connecting 34. The area of each cross section orthogonal to the X-axis direction of the front slider 33 and the rear slider 34 is the same, and is larger than the area of the cross section of the connecting portion 35. Further, the rear slider 34 is offset to the upper side in the Z-axis direction with respect to the front slider 33.

  The front slider 33 is formed with a pressing surface 36 that receives pressure in the pressing direction by pressurized air. The pressing surface 36 is a surface orthogonal to the X axis formed on the lower side of the connection portion with the connecting portion 35. The height dimension of the pressing surface 36 in the Z-axis direction is the same as the offset amount of the front slider 33 and the rear slider 34. Similarly, a suction surface 37 that receives pressure in the pulling direction is formed on the rear slider 34 on the upper side of the connection portion with the connecting portion 35.

The slider support member 32 has an internal space 321 formed so as to penetrate in the X-axis direction, and supports the slider 31 inserted through the internal space 321.
The internal space 321 includes a first bearing portion 322 as an air bearing that pivotally supports the front slider 33 in order along the X axis from the workpiece W side, and a constant pressing pressure of the tool T against the workpiece W by pressurized air. And a constant pressure generating portion 323 to be pressed and a second bearing portion 324 as an air bearing that pivotally supports the rear slider 34.
The first bearing portion 322 and the second bearing portion 324 are offset from each other in the Z-axis direction corresponding to the front slider 33 and the rear slider 34 of the slider 31.

  The first bearing portion 322 is a porous throttle bearing, and a supply passage 327 connected to the first compressed air passage 51 (FIG. 1) is communicated with the first bearing portion 322, so that pressurized air passes through a plurality of holes. Air is supplied toward the outer peripheral surface of the slider 33. Thus, the first bearing portion 322 supports the front slider 33 in a non-contact manner by the pressurized air supplied between the outer peripheral surface of the front slider 33 and the inner peripheral surface of the internal space 321. Similarly, the second bearing portion 324 is also a porous throttle bearing, and passes through a supply passage 328 connected to the second compressed air passage 52 between the outer peripheral surface of the rear slider 34 and the inner peripheral surface of the internal space 321. The rear slider 34 is pivotally supported by the supplied pressurized air in a non-contact manner. Thus, the slider 31 floats from the inner peripheral surface of the internal space 321 and the slider 31 and the slider support member 32 are not in contact with each other.

In FIG. 2, the constant pressure generating portion 323 is formed at a position between the first bearing portion 322 and the second bearing portion 324 and at a position corresponding to the connecting portion 35 of the slider 31. The constant pressure generating unit 323 is divided into two upper and lower spaces by the slider 31 and includes a lower pressing pressure generating unit 325 and an upper pulling pressure generating unit 326. A supply path 329 for supplying pressurized air is communicated with the inner peripheral surface of the pressing pressure generator 325, and this supply path 329 is connected to the third compressed air path 53 (FIG. 1). The supply path 330 is also communicated with the inner peripheral surface of the suction pressure generating unit 326, and the supply path 330 is connected to the fourth compressed air path 54.
The pressing pressure generation unit 325 and the suction pressure generation unit 326 are formed so that the respective volumes occupied by the supplied pressurized air increase or decrease as the slider 31 moves. That is, when the slider 31 moves in the pressing direction, the position of the pressing surface 36 moves in the pressing direction, the volume of the pressing pressure generating unit 325 increases, and the position of the pressing surface 37 also moves at the same time. The volume of is reduced. Conversely, when the slider 31 moves in the pulling direction, the volume of the pressing pressure generating unit 325 decreases and the volume of the pulling pressure generating unit 326 increases.

  As shown in FIG. 1, the compressed air path 5 is branched into three paths from the compressor 4, and a third compressed air path 53 communicated with the pressing pressure generating unit 325 and a fourth compressed air path 54 communicated with the attractive pressure generating unit 326. And a bearing part compressed air passage 55. The three paths 53 to 55 include a regulator 56 (561 to 563) for setting the flow rate and pressure of pressurized air from the compressor 4 and a pressure gauge 57 (571 to 573) for detecting the set pressure. Provided. The bearing-part compressed air path 55 is branched into two paths on the downstream side of the pressure gauge 57 and includes a first compressed-air path 51 and a second compressed-air path 52 that communicate with the bearing sections 322 and 324.

A displacement meter 38 for detecting the position of the tool T in the moving direction is fixed to the slider support member 32. The displacement meter 38 is attached in a posture facing the end surface 311 of the slider 31 and detects the amount of displacement of the position of the end surface 311. As the displacement meter 38, for example, a laser type or a capacitance type displacement meter can be adopted. In the present embodiment, a laser displacement meter having a detection resolution of 0.0084 μm and a response frequency of several hundred kHz is used.
Detection values of the pressure gauge 57 and the displacement gauge 38 are input to the control device 6. In the control device 6, the control amount of the regulator 56 is calculated based on the input detection value, and the regulators 561 and 563 are operated by this control amount. Thereby, the pressure and flow rate of the pressurized air are changed.

<Operation of tool movement mechanism>
In FIG. 2, by supplying pressurized air to the first bearing portion 322 and the second bearing portion 324, the frictional resistance between the slider 31 and the inner peripheral surface of the internal space 321 is remarkably reduced, and the slider 31 and the tool T are in a state in which they can slide smoothly in the X-axis direction. Further, the amount and pressure of the pressurized air are set by the regulators 561 (FIG. 1) for the respective bearing portions 322 and 324, and the floating state of the slider 31 from the inner peripheral surface of the internal space 321 of the slider support member 32 is strictly determined. To be determined. Thus, the positioning (so-called centering) of the slider 31 in the Y-axis and Z-axis directions is performed precisely.

When pressurized air is supplied to the pressing pressure generator 325, a pressing pressure in a direction in which the slider 31 is pressed against the pressing surface 36 acts. Further, when pressurized air is supplied to the suction generation unit 326, the suction in the direction of pulling the slider 31 acts on the suction surface 37. The pressures of the pressurized air to the pressing pressure generation unit 325 and the suction pressure generation unit 326 are set by regulators 562 and 563 (FIG. 1), respectively.
When the cutting process is not performed, the pressing pressure generating unit 325 and the pulling pressure generating unit 326 are supplied with pressurized air of the same pressure, and the generated pressing pressure and the pulling pressure are balanced so that the slider 31 is balanced in the X-axis direction. It becomes a state.
On the other hand, when the tool moving mechanism 3 is advanced by the X-axis drive mechanism 7 to cut the workpiece W, pressurized air having a pressure higher than that of the pulling pressure generating unit 326 is supplied to the pressing pressure generating unit 325, Generates an effective pressing pressure (pressing pressure-pulling pressure), and the tool T is pressed against the workpiece W with the effective pressing pressure. During the cutting process, the pressure of the supplied pressurized air is set by the regulators 562 and 563 so that the effective pressing pressure is constant.

When the slider 31 moves backward in the X-axis direction depending on the cutting situation, the volume of the pressing pressure generating portion 325 decreases, and an amount of air corresponding to the reduced amount is released to the atmosphere through the first and second bearing portions 322 and 324. The At this time, since the pressurized air for the bearing portion is supplied to the first and second bearing portions 322 and 324, as shown in FIG. 2, energy is generated when the air of the pressing pressure generating portion 325 passes. Is consumed. Since the consumed energy depends on the moving speed of the slider 31, the backward movement of the slider 31 is attenuated.
Similarly, when the slider 31 is retracted, the volume of the attractive pressure generating part 326 is reduced, and energy is consumed when the air of the attractive pressure generating part 326 passes through the first and second bearing parts 322 and 324, The forward movement of the slider 31 is attenuated.

  During the cutting process, the displacement meter 38 constantly monitors the slider 31 and outputs a displacement amount signal of the slider 31 to the control device 6. The first and second bearing portions 322 and 324 have a high restraining force in directions other than the X-axis direction of the slider 31, so that the displacement meter 38 can accurately operate the slider 31 in the cutting direction. Can be monitored.

FIG. 3 is a conceptual diagram of the tool moving mechanism of the present embodiment.
In FIG. 3, K indicates a spring, and C indicates a damper.
That is, maintaining the effective pressing pressure constant in the above-described constant pressure generating portion 323 indicates that the tool T is pressed against the workpiece W with the constant pressing force by the spring K in the figure, whereby the tool T is pressed against the workpiece W. Therefore, the cutting depth of the tool T is constant.
In addition, when the slider 31 moves in the X-axis direction, the air in the pressing pressure generating portion 325 or the suction pressure generating portion passes through the first and second bearing portions 322 and 324 and energy is consumed. It shows that the movement in the X-axis direction of the tool T is attenuated by the damper C in the inside, and thereby, it is possible to suppress the occurrence of chatter or the like that is likely to occur when the cutting depth of the tool T is very small.

<Effect of embodiment>
In the present embodiment, the following effects can be expected.
(1) Since the slider 31 is provided so as to be movable in the X-axis direction and the slider 31 is pressed against the workpiece W with a constant pressing pressure, the tool moves in the moving direction according to the unevenness of the machining surface of the workpiece W. Moving. Accordingly, the cutting amount of the tool T can be maintained at a constant amount regardless of the shape of the processing surface of the workpiece W and the dynamic and static accuracy of the processing apparatus. Therefore, stable ductile mode processing can be performed on a hard and brittle material that requires a small critical depth of cut.

(2) In addition, it is possible to easily set the pressure difference corresponding to the cutting depth of the tool T only by changing the pressure of the pressurized air supplied to the pressing pressure generating unit 325 and the pulling pressure generating unit 326, respectively. It is possible to improve the efficiency of the processing work.

(3) When the slider 31 holding the tool T moves in the pushing direction, the pressurized air of the pressing pressure generating unit 325 and the pulling pressure generating unit 326 consumes energy by the air of the first bearing unit 322 and the second bearing unit 324. To do. The movement of the slider 31 is attenuated by this energy consumption, chattering and the like generated on the slider 31 can be suppressed, and stable machining can be maintained.

(4) Even when the support rigidity of the tool T becomes low, the displacement amount of the slider 31 holding the tool T is detected by a displacement meter 38 such as a laser displacement meter or a capacitance displacement meter, and the control device 6 It is possible to foresee or detect chattering of the tool T and the like. Furthermore, by operating each regulator 56 according to the prediction or detection result of chatter or the like, the pressing force can be changed in real time during the cutting process, and the machining in a stable region where chatter or the like does not occur can be maintained. .

<Modification>
The present invention is not limited to the above-described embodiment, and modifications, improvements, and the like within the scope that can achieve the object of the present invention are included in the present invention.
For example, the processing method of the above embodiment is not limited to cutting, and can also be applied to grinding.
Further, in the machining method of the above embodiment, the tool T can be made to follow the shape of the machined surface of the workpiece W by keeping the pressing pressure of the tool T against the workpiece W constant, and the cutting depth can be kept constant. However, the present invention is not limited to this, and the cutting amount can be controlled by appropriately changing the pressing pressure of the tool T according to the shape of the machining surface. The present processing method may be applied to arbitrary processing.

  In the above-described embodiment, the shape of the slider 31 has been described as a substantially prismatic shape, but it may be formed of a cylindrical front slider and a rear slider. Further, the slider 31 has been described as having a shape in which the front slider 33 and the rear slider 34 are arranged on the front and rear sides via the connecting portion 35. However, the front slider 33 and the rear slider 34 are directly connected, and the pressing surface 36 and the pulling slider 34 are pulled. The pressure surface 37 may be formed at the same position on the X axis. In the above-described embodiment, the pressing surface 36 has a shape that is disposed in front of the suction surface 37, but the pressing surface 36 may have a shape that is disposed behind the suction surface 37.

  In the above-described embodiment, the tool moving mechanism 3 is configured to be movable in the X-axis and Y-axis directions by the X-axis drive mechanism 7 and the Y-axis drive mechanism 8. However, the present invention is not limited to this. You may comprise so that a movement to a Y-axis direction is possible.

  The present invention can be used, for example, for machining a machine tool or the like that forcibly pushes a cutting tool to control a cutting depth.

The front view which shows one Embodiment of the processing apparatus of this invention. Sectional drawing which shows the tool movement mechanism of embodiment same as the above. The conceptual diagram of the tool movement mechanism of embodiment same as the above.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 ... Base 2 ... Work rotation mechanism (work support means)
3. Tool moving mechanism (constant pressure mechanism)
5 ... Pressure air path (pressure air supply means)
31 ... Slider (movable member)
32 ... Slider support member (support member)
38 ... Displacement meter 322 ... 1st bearing part (air bearing)
324 ... Second bearing portion (air bearing)
325 ... Pressing pressure generator 326 ... Attraction generator T ... Tool W ... Workpiece.

Claims (4)

A machining method of machining the workpiece with the tool while relatively moving the tool and the workpiece,
A movable member that holds the tool and is movable in the direction of pressing and pulling the tool against the workpiece;
A support member that movably supports the movable member;
A pressing pressure generating section that generates a pressing pressure for pressing the movable member in the pressing direction;
An attraction generating section for generating attraction pulling in a direction in which the movable member is separated;
Using a constant pressure mechanism having
While making the pressure difference between the pressurized air supplied to the pressing pressure generating unit and the pulling pressure generating unit constant, and processing the movable member while pressing the workpiece with a constant pressing pressure ,
During this processing, the displacement amount in the moving direction of the movable member is detected by a displacement meter, and the displacement amount of the movable member detected by the displacement meter is evaluated to predict or detect the chatter of the tool. Alternatively, according to a detection result, a processing method characterized in that the pressing force applied to the workpiece is changed by adjusting the pressure of the pressurized air supplied to the pressing pressure generation unit and the pulling pressure generation unit . The processing method according to claim 1,
The processing method characterized by setting the pressure difference of the pressurized air respectively supplied to the said pressing pressure generation | occurrence | production part and the said drawing pressure generation | occurrence | production part according to the cutting amount with respect to the said workpiece | work of the said tool. Base and
A workpiece support means provided on the base for gripping the workpiece;
A tool for machining the workpiece;
A constant pressure mechanism that is provided on the base and presses the tool against the workpiece with a constant pressing pressure, and a processing device that processes the workpiece with the tool while relatively moving the tool and the workpiece,
The constant pressure mechanism is
A movable member that holds the tool and is movable in the direction of pressing and pulling the tool against the workpiece;
A support member that movably supports the movable member;
A pressing pressure generating section that generates a pressing pressure for pressing the movable member in the pressing direction;
A pulling pressure generating section that generates a pulling pressure that pulls the movable member in a direction of separating,
While having a compressed air supply means for supplying pressurized air to the pressing pressure generating section and the pulling pressure generating section ,
Furthermore, a displacement meter that detects a displacement amount in the moving direction of the movable member;
The displacement amount of the movable member detected by the displacement meter is evaluated to predict or detect chatter of the tool, and depending on the prediction or detection result, the pressing pressure generating unit and the pulling pressure generating unit are respectively A processing apparatus comprising: a control device that adjusts the pressure of the supplied pressurized air to change a pressing force of the tool against the workpiece. In the processing apparatus according to claim 3,
The support member is provided with air bearings at two locations sandwiching the pressing pressure generating portion and the attractive pressure generating portion,
The movable member is pivotally supported by the air bearing,
The processing apparatus according to claim 1, wherein the pressing pressure generation unit and the attraction pressure generation unit communicate with outside air through the air bearing.

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