JP2021091091A - Cutting device - Google Patents

Abstract

To provide a technique for finding information related to a tool edge.SOLUTION: A control part 20 has a function of moving a cutting tool 11 in a translation direction relatively to an object having an arcuate surface in a known shape to acquire coordinate values when an arcuate edge of the cutting tool 11 comes into contact with the arcuate surface of the object by using detection information of a contact sensor or time-series data on detection values related to a drive motor included in a rotary mechanism 8 and/or a feed mechanism 7 and related to the drive motor. The control part 20 finds, based upon coordinate values when the arcuate edge of the cutting tool 11 and the arcuate surface of the object come into contact at least at three respectively different positions: at least one of a nose radius of the tool edge, center coordinates of the tool edge, and a shape error of the tool edge.SELECTED DRAWING: Figure 1

Description

The present disclosure relates to a cutting device that cuts a work material (work) using a cutting tool.

Conventionally, as a method of setting the origin in a cutting device, the cutting edge position of a cutting tool is measured by a measuring instrument and the cutting edge position is adjusted. Another method is to process the work material once with a cutting tool, measure the shape of the work material after processing with a measuring instrument, and correct the cutting edge position from the measurement result. These are all origin setting methods using a measuring instrument.

Patent Document 1 discloses a contact detection device that detects contact with a rotary tool mounted on a spindle of a processing machine. This contact detection device includes a disk-shaped contactor that can come into contact with the rotary tool, and a vibration sensor that detects contact vibration when the contactor and the rotary tool come into contact with each other. By bringing the rotary tool into contact with the flat surface portion and the side surface portion of the contactor, the length and outer diameter of the rotary tool are measured, and the exact position of the rotary tool is grasped.

Patent Document 2 relatively moves the cutting edge of a cutting tool and the object to be contacted to bring them into contact with each other, and based on the moving position of the moving device at the time of contact, the subsequent relative movement of the cutting tool and the workpiece is performed. A method of controlling the position of the cutting tool to be controlled is disclosed. In this method, the position of the cutting tool moving device at that time is detected by utilizing the fact that the electric circuit is closed and the current flows when the cutting edge comes into contact with the object to be contacted. The detected position is used as a reference position for subsequent movement control of the cutting tool.

Patent Document 3 compares the position deviation input from the X-axis servo means with the reference value set by the position deviation reference value setting means, and determines the contact between the work and the probe when the position deviation exceeds the reference value. Disclose the technology.

Japanese Unexamined Patent Publication No. 2004-90199 JP-A-2002-120130 Japanese Unexamined Patent Publication No. 2009-34738

It is not preferable to provide a measuring instrument for measuring the position of the cutting edge, the shape of the work material after machining, etc. for the purpose of setting the origin because of high cost. Therefore, it is desired to realize highly accurate origin setting without using a measuring instrument.

The present disclosure has been made in view of such circumstances, and one of the purposes thereof is to specify the relative positional relationship between the tool cutting edge and an object such as a work material without adding a measuring instrument. The purpose is to provide the technology, or the technology required to identify the relative positional relationship between the two.

In order to solve the above problems, the cutting device of an embodiment of the present invention has a rotating mechanism for rotating a spindle to which a cutting tool or a work material is attached, and a cutting tool relative to the work material or a part. It includes a feed mechanism for moving and a control unit for controlling the rotation of the spindle by the rotation mechanism and the relative movement of the cutting tool by the feed mechanism. The control unit uses the detection information of the contact sensor or the time-series data of the detection values of the drive motor included in the rotation mechanism and / or the feed mechanism to determine the coordinate values when the cutting tool comes into contact with the work material or part. It has a function to acquire. The control unit is at least 2 different from the rotation angle position of the cutting tool during turning with respect to the reference plane whose relative positional relationship with the work material after turning or the rotation center of the work material is known. At one position, the relative positional relationship between the cutting tool and the center of rotation of the work material is determined based on the coordinate values when the cutting tool comes into contact.

Another aspect of the present invention is also a cutting device. This cutting device is based on a rotating mechanism that rotates a spindle to which a cutting tool or work material is attached, a feed mechanism that moves the cutting tool relative to an object, and a spindle rotation and feed mechanism that uses a rotating mechanism. It is provided with a control unit that controls the relative movement of the cutting tool. The control unit moves the cutting tool relative to an object with a known shape, and obtains the coordinate values when the cutting edge of the cutting tool comes into contact with the known shape of the object, such as the detection information of the contact sensor, or the rotation mechanism and / Alternatively, it has a function of acquiring using time-series data of detected values related to the drive motor included in the feed mechanism. The control unit has at least the nose radius of the tool cutting edge, the center coordinates of the tool cutting edge, and the shape error of the tool cutting edge based on the coordinate values when the cutting tool cutting edge contacts at least three positions of the known shape part of the object. Ask for one.

Yet another aspect of the present invention is also a cutting device. This cutting device includes a rotating mechanism that rotates a spindle to which a cutting tool or a work material is attached, a feed mechanism that moves the cutting tool relative to the work material, and a spindle rotation and feed mechanism by the rotation mechanism. It is provided with a control unit that controls the relative movement of the cutting tool. The control unit acquires the coordinate value when the cutting tool comes into contact with the work material by using the detection information of the contact sensor or the time series data of the detection value of the drive motor included in the rotation mechanism and / or the feed mechanism. Has a function. The control unit moves the cutting tool relative to the work material after cutting by using the feed function of the feed mechanism in the movement direction that was not used during cutting, and there are at least two cutting tools. Based on the coordinate values at the time of contact at the position, at least one of the mounting error of the cutting tool, the shape error of the cutting edge of the tool, and the deviation of the cutting tool in the relative movement direction with respect to the work material is specified.

Yet another aspect of the present invention is also a cutting device. This cutting device is included in a rotating mechanism that rotates a spindle to which a cutting tool or a work material is attached, a feed mechanism that moves the cutting tool relative to the work material, and a rotation mechanism and / or a feed mechanism. It is provided with a control unit that identifies the contact position between the cutting tool and the work material from the time-series data of the detected values of the drive motor. The control unit identifies the contact position based on the first time-series data of the detected value acquired before the contact and the second time-series data of the detected value acquired after the contact.

It should be noted that any combination of the above components and the conversion of the expression of the present disclosure between methods, devices, systems, recording media, computer programs and the like are also effective as aspects of the present disclosure.

According to the present disclosure, it is possible to provide a technique for specifying a relative positional relationship between a tool cutting edge and an object, and a technique required for specifying a relative positional relationship between the two.

It is a figure which shows the schematic structure of the cutting apparatus. It is a figure which shows the outline of the experiment about the contact detection method. It is a figure which shows the state which the cutting edge is in contact with a work and cut. It is a figure which shows the time change of the internal information about a feed axis during an experiment. It is a figure which shows the time change of the internal information about the spindle rotation axis during an experiment. It is a figure which shows the time change of the cutting amount of a cutting edge. It is a figure which shows the change of the detection value by the external sensor of the main component force of a cutting force. It is a figure which shows the change of the detected value of a torque output. It is a figure which shows the change of the main component force which removed the noise by signal processing the detected value of the main component force. It is a figure which shows the torque change which removed the noise by signal processing the torque detection value. It is a figure for demonstrating the method of determining the relative positional relationship between a cutting tool and the center of rotation of a work material. It is a figure which shows the derivation method of the A point coordinate. It is a figure for demonstrating the reference plane. It is a figure which shows an example of the cutting apparatus which attached the cutting tool rotatably about C axis. It is a figure which shows the state which the cutting edge and the known shape part of a reference block came into contact with each other. It is a figure which shows the positional relationship between a cutting edge and a reference block. It is a figure which shows typically the tilted state of a cutting tool when it comes into contact with the upper surface of a reference block. It is a figure which shows the height change of a contact position. It is a figure which shows another example of the cutting apparatus which attached the cutting tool rotatably about C axis. It is a figure which shows the state which the cutting edge and the known shape part of a reference block came into contact with each other. It is a figure which shows the positional relationship between a cutting edge and a reference block. It is a figure which shows the state which brought the part of the known shape of a reference block into contact with a cutting edge. It is a figure which shows the state of processing a work material. It is a figure for demonstrating the method of deriving the mounting error of a tool center. It is a figure for demonstrating the method of specifying the shape error of a tool cutting edge. It is a figure for demonstrating the method of specifying the parallelism of the work material rotation axis and the tool straight axis. It is a figure for demonstrating the method of specifying the orthogonality degree of the work material rotation axis and the tool straight axis. It is a figure for demonstrating the method of estimating the mounting error of a tool center. It is a figure for demonstrating the method of estimating the mounting error of a tool center. It is a figure for demonstrating the method of estimating the mounting error of a tool center. It is a figure for demonstrating the method of deriving the B-axis rotation center. It is a figure which conceptually shows the cutting feed direction and the pick feed direction in scanning line processing. It is a figure for demonstrating the method of estimating the mounting error of a tool center. It is a figure for demonstrating the method of estimating the mounting error of a tool center. It is a figure which shows the method of measuring the cutting edge shape error. It is a figure which shows the state of processing by a straight cutting edge. It is a figure for demonstrating the identification method. It is a figure for demonstrating the coordinate transformation. It is a figure which shows the state which the cutting edge is in contact with a machined surface. It is a figure which shows two different postures of a ball end mill. It is a figure for demonstrating the method of specifying the misalignment amount. It is a figure for demonstrating the method for specifying the deviation amount of the B-axis rotation center. It is a figure for demonstrating the method of specifying the deviation amount from a right angle between X-axis and Z-axis. It is a figure which conceptually shows the cutting feed direction and the pick feed direction in scanning line processing. It is a figure for demonstrating the method of estimating the mounting error of a tool center. It is a figure for demonstrating the method of estimating the mounting error of a tool center. It is a figure which shows the method of measuring the cutting edge shape error.

FIG. 1 shows a schematic configuration of the cutting device 1 of the embodiment. The cutting device 1 shown in FIG. 1 is a cutting device for turning by bringing the cutting edge 11a of the cutting tool 11 into contact with the work material 6. The cutting device 1 may be an NC machine tool. The cutting device 1 shown in FIG. 1 is a roll lathe that turns a cylindrical work material 6 to process a rolling roll, but may be a cutting device of a type other than turning, for example, an end mill or the like. It may be a cutting device that uses a rotary tool.

The cutting device 1 includes a spindle base 2 and a tailstock 3 that rotatably support the work material 6 and a cutting tool base 4 that supports the cutting tool 11 on the bed 5. The rotation mechanism 8 is provided inside the spindle base 2 and rotates the spindle 2a to which the work material 6 is attached. The feed mechanism 7 is provided on the bed 5 and moves the cutting tool 11 relative to the work material 6. In this cutting device 1, the feed mechanism 7 moves the tool post 4 in the X-axis, Y-axis, and Z-axis directions to move the cutting tool 11 relative to the work material 6.

In FIG. 1, the X-axis direction is the cutting direction which is horizontal and orthogonal to the axial direction of the work material 6, the Y-axis direction is the vertical direction, and the Z-axis direction is the axial direction of the work material 6. The feed direction is parallel to. In FIG. 1, the positive and negative directions of the X-axis, Y-axis, and Z-axis indicate the directions seen from the cutting tool 11 side, but the positive and negative directions are relative between the cutting tool 11 and the work material 6. Therefore, in this specification, the positive and negative directions of each axis are not strictly defined, and when the positive and negative directions are referred to, the directions shown in each figure are followed.

The control unit 20 has a rotation control unit 21 that controls the rotation of the spindle 2a by the rotation mechanism 8 and a cutting tool 11 that is brought into contact with the work material 6 by the feed mechanism 7 during the rotation of the spindle 2a to perform machining by the cutting tool 11. The movement control unit 22 to be performed and the positional relationship deriving unit 23 for deriving the relative positional relationship between the work material 6 and the cutting tool 11 are provided. The movement control unit 22 may control the movement of the cutting tool 11 with reference to the coordinates of the cutting edge 11a. The rotation mechanism 8 and the feed mechanism 7 are respectively configured to have a drive unit such as a drive motor, and the rotation control unit 21 and the movement control unit 22 adjust the power supply to the drive unit, respectively, to adjust the rotation mechanism 8 and the feed mechanism 7. The behavior of each of the feed mechanisms 7 is controlled.

In the cutting device 1 of the embodiment, the work material 6 is attached to the spindle 2a and rotated by the rotating mechanism 8, but in another example, a cutting tool which is a rotating tool is attached to the spindle 2a and the rotating mechanism 8 is used. May be rotated by. Further, the feed mechanism 7 may move the cutting tool 11 relative to the work material 6, and may have a mechanism for moving at least one of the cutting tool 11 or the work material 6.

Further, the feed mechanism 7 is not limited to the feed function in the translational direction of the X-axis, the Y-axis, and the Z-axis, and may have a feed function in the rotation direction of the A-axis, the B-axis, and the C-axis. It is preferable that the feed mechanism 7 of the embodiment has not only a feed function in a moving direction required for cutting, but also a feed function in a moving direction that is not used in cutting. That is, the feed mechanism 7 is configured to have a feed function in the moving direction that is not required for the cutting process (so to speak, redundant) in addition to the feed function in the direction used in the cutting process. The redundant feed function in the direction may be used when the cutting tool 11 is relatively moved with respect to the premachined surface described later.

When the cutting tool 11 is newly attached to the cutting device 1 such as when changing tools, in order for the movement control unit 22 to obtain high movement accuracy (machining accuracy), the origin setting is appropriately performed and the cutting edge 11a The exact coordinate values need to be identified. In the embodiment, when the origin is set, the movement control unit 22 moves the cutting edge 11a to bring it into contact with an object (for example, a preprocessed work material 6), specifies the timing of contact, and controls the movement at that time. The contact position is specified from the control information of the unit 22. Therefore, the cutting device 1 may have a contact sensor that detects that the cutting edge 11a has come into contact with an object. The contact sensor may be, for example, a vibration sensor that detects vibration at the time of contact, or a sensor that detects continuity when the cutting edge comes into contact with an object.

The cutting device 1 of the embodiment is equipped with a function of analyzing the history of internal information of the cutting device 1 that changes when the cutting edge 11a comes into contact with an object and detecting the contact between the cutting edge 11a and the object. May be good. By using the detected value of the drive motor included in the rotation mechanism 8 and / or the feed mechanism 7 as the internal information, it is not necessary to add a new component. When the cutting device 1 is equipped with this function, a sensor for detecting contact is not required, but a contact sensor may be provided for the purpose of improving the contact detection accuracy.

FIG. 2 shows an outline of an experiment on a contact detection method. This experiment was carried out to verify the contact detection method using inside information, and it is assumed that the origin setting has already been carried out. The work W was H3250 C4641BE (naval brass) and used a round bar with a diameter of 70 mm. During the experiment, the rotation control unit 21 rotates the spindle to which the work W is attached at a rotation speed of 120 rpm. The movement control unit 22 brings the cutting tool 11 close to the cutting tool 11 at a feed rate of 0.2 mm / rev, cuts the cutting tool 11 to a cutting depth of 0.1 mm, and then pulls the cutting tool 11 apart at the same feed rate. FIG. 3 shows a state in which the cutting edge 11a is in contact with the work W and cuts.

FIG. 4 shows the time variation of internal information about the feed axis during the experiment. The movement control unit 22 starts feeding the cutting tool 11 at time t2, feeds the cutting tool 11 in the cutting direction at a constant feed rate of 0.2 mm / rev, and cuts to a depth of 0.1 mm (time t3). After that, the movement control unit 22 pulls the cutting tool 11 apart at a feed rate of 0.2 mm / rev.
FIG. 5 shows the time change of the internal information about the spindle rotation axis during the experiment. The rotation control unit 21 starts the rotation of the spindle at time t1. The rotation speed is 120 rpm.
FIG. 6 shows the time change of the cutting amount of the cutting edge. The depth of cut is calculated from the internal information of the feed shaft shown in FIG.

FIG. 7 shows the change in the value detected by the external sensor of the main component force of the cutting force. The cutting device used in this experiment is equipped with an external sensor for detecting the cutting force, and FIG. 7 shows the time change of the cutting force detected by the external sensor.
FIG. 8 shows a change in the detected value of the torque output. The torque detection value is calculated using the estimation function installed in the cutting device. The torque value is proportional to the motor current value, and the cutting device acquires the motor current of the drive motor of the spindle and calculates the torque output.
The waveform of the main component force shown in FIG. 7 and the waveform of the torque value shown in FIG. 8 are substantially the same. Therefore, by analyzing the torque output (motor current), it can be seen that the contact between the work W and the cutting tool 11 can be detected.

FIG. 9 shows a change in the main component force by signal processing the detected value of the main component force to remove noise.
FIG. 10 shows a torque change in which noise is removed by signal processing the torque detection value. By removing noise, the reliability of the time series data of the torque detection value can be improved.
Hereinafter, a method in which the control unit 20 determines the contact between the cutting tool 11 and the work W from the time-series data of the torque detection value processed by the signal is shown. The control unit 20 can also determine the contact by using the time series data of the torque detection value before the signal processing. The positional relationship deriving unit 23 of the embodiment has a function of specifying the contact position from the time series data of the detected values related to the drive motor included in the rotation mechanism 8 and / or the feed mechanism 7.

After the movement control unit 22 finishes feeding the cutting tool 11, the positional relationship deriving unit 23 acquires the time series data of the torque estimation value shown in FIG. 10, and the first time series data of the detected value acquired before the contact. And, the second time series data of the detection value acquired after the contact is specified. At this time, since the positional relationship derivation unit 23 does not know the contact timing, the first time series data and the second time series data are specified according to the following criteria.

As shown in FIG. 5, the rotation control unit 21 starts rotating the spindle from time t1, and as shown in FIG. 4, the movement control unit 22 starts feeding the cutting tool 11 from time t2. Therefore, during the time t1 to t2, the spindle is rotating and the cutting tool 11 is surely in a non-contact state. Therefore, the positional relationship derivation unit 23 specifies the time-series data of the torque detection value calculated between the times t1 and t2 as the first time-series data before the contact. Even after the start of feeding of the cutting tool 11, that is, after the time t2, if it is a time zone in which it is certain that the cutting tool 11 is before the contact, the torque detection value acquired in the time zone is used as the first time series data. May be included.

The positional relationship derivation unit 23 calculates _{the average value M 1} and the standard deviation σ _{1 of the specified first time series data.} In this experiment
M ₁ = 0.1045
σ ₁ = 0.0043
Is calculated.
10, line L1, the torque average value _{M 1} of the prior contact, line L2, an average value _M 1 + 2 [sigma] _1, line L3 _shows the M ₁ -2σ 1.

Next, the positional relationship derivation unit 23 specifies the second time series data of the torque detection value acquired after the contact. The positional relationship derivation unit 23 may specify the time-series data of the torque detection value exceeding a predetermined threshold value as the second time-series data. The positional relationship derivation unit 23 may set a predetermined threshold value based on the first time series data. For example, the positional relationship derivation unit 23 sets a predetermined threshold value as (M ₁ + 3σ ₁ ), and specifies continuous time series data of torque detection values exceeding this threshold value as second time series data. When specifying the second time series data, the time zone in which the torque detection value less than the threshold value is included in the predetermined ratio (for example, 2%) or less is regarded as the time zone in which the threshold value is substantially exceeded. 2 It may be included in the time series data. The positional relationship derivation unit 23 specifies the torque detection value as the second time series data from the time t3 to the time when the torque detection value becomes (M ₁ + 3σ _{1) or less.}

σ_２＝0.0031
と算出される。Ｘ軸は時間、Ｙ軸はトルク出力である。なお回帰式は、２次以上の近似曲線で表現されてもよい。図１０において、ラインＬ４は１次近似直線である回帰式を、ラインＬ２、Ｌ３は回帰式をＹ軸方向にそれぞれ２σ_２、−２σ_２だけずらしたラインを示す。 The positional relationship derivation unit 23 calculates the timing at which the cutting edge 11a comes into contact with the work W from the regression equation obtained by regression analysis of the second time series data and the average value of the first time series data. An appropriate regression analysis method may be used. For example, the positional relationship derivation unit 23 derives the regression equation and standard deviation σ ₂ of the second time series data by the least squares method, and the regression equation and the torque. Find the intersection with the average value M1. In this experiment

σ ₂ = 0.0031
Is calculated. The X-axis is time and the Y-axis is torque output. The regression equation may be expressed by an approximate curve of degree 2 or higher. 10, the line L4 is the regression equation is first order approximation straight line, the line L2, L3 denotes a line obtained by shifting the regression equation 2 [sigma] _2, respectively in the Y-axis direction, only -2σ _2.

により、刃先１１ａがワークＷに接触したことが推定されるタイミングｐ_２が算出される。
なお信頼区間を９５％（２σ）として最大誤差を推定すると、△マークのポイントは、ラインＬ３とラインＬ５の交点、□マークのポイントは、ラインＬ２とラインＬ４の交点である。したがって、

により最大時間誤差を含む接触タイミングｐ_１、ｐ_３が算出される。この結果、実験による接触位置の最大誤差ｅ_ｐは、0.019mmと求まる。 In FIG. 10, the point marked with a circle is the intersection of the line L1 and the line L4. Therefore,

The timing p ₂ where the cutting edge 11a is estimated that in contact with the workpiece W is calculated.
When the maximum error is estimated with the confidence interval set to 95% (2σ), the points marked with Δ are the intersections of line L3 and line L5, and the points marked with □ are the intersections of line L2 and line L4. Therefore,

Contact including the maximum time error timing p _1, p ₃ is calculated by. As a result, the maximum error e _p of the contact position by experiments, obtained with the 0.019 mm.

In this way, the positional relationship derivation unit 23 calculates the contact timing from the time series data of the detected values related to the drive motor. Compared with the case where the timing when the detected amount exceeds a predetermined threshold value is simply determined as the contact timing, this method uses a regression equation derived from the history of the detected amount, so that the detected amount is before the threshold value is reached. Accurate contact timing can be obtained.

In this method, since the cutting tool 11 or the work W is brought close to each other while rotating or rotating in the reverse direction to perform minute cutting or burnishing (pushing), minute cutting marks or indentations are left on the surface of the work W. Therefore, it is not desirable to apply this method after final finishing, but if this method is applied before that and then final finishing is performed, minute cutting marks / indentations will be generated when this method is applied. There is no problem in remaining.

In the case of continuous turning, as shown in FIG. 10, a detected value that slowly increases as the cutting edge 11a slowly cuts is acquired. On the other hand, in the case of intermittent cutting such as milling, cutting force or burnishing force is generated intermittently by making contact while rotating. When measuring the current value of the rotary spindle motor corresponding to such an intermittent force, a time series in which the average value or the maximum value of the values measured over each rotation cycle and each cutting edge passing cycle is used as the detection value. Data may be adopted. As described above, in this method, by processing the work W to some extent, the contact area can be enlarged and the resolution can be improved, and even in the case of a rotary tool, it is not necessary to specify the rotation position, and practical contact is made. Detection can be realized.

The cutting device 1 of the embodiment acquires a history of detected values related to the drive motor after the contact between the cutting tool 11 and the work W, and analyzes the detected values before the contact by tracing back to the detected values before the contact. The contact timing can be accurately derived and the contact position can be determined. In the above experiment, the torque output value estimated by the function installed in the cutting device was used as the detection value for the drive motor, but in the cutting device that does not have the torque estimation function, the current detection value of the spindle rotary motor and the feed Contact detection may be performed using the time-series data of the current detection value of the shaft rotation motor, the time-series data of the detection value by the encoder, or the like.

In this way, the control unit 20 has a function of controlling the feed mechanism 7 to relatively move the cutting tool 11 and acquiring coordinate values when the cutting edge 11a comes into contact with a contact object such as a work material 6. The cutting device 1 may include a contact sensor, and the control unit 20 may detect the contact from the sensing data from the contact sensor and acquire the coordinate value at the time of contact. Hereinafter, a method of determining the relative positional relationship between the cutting tool 11 and the object in the cutting device 1 will be described on the premise that the cutting device 1 has a contact detection function. In the first embodiment, the rotation center of the work material 6 has the same meaning as the rotation center of the spindle 2a.

<Example 1>
FIG. 11 is a diagram for explaining a method for determining the relative positional relationship between the cutting tool and the center of rotation of the work material. Hereinafter, a method for calculating the rotation axis center A (x, y) of the work material 6 will be described. In this example, the work material 6 is in a state of being turned once. The work material 6 is preferably rotated by the spindle 2a from the viewpoint of preventing the sharp tool cutting edge from being damaged, but it may not be rotated.

Movement control unit 22 First, by moving the tool edge from below upward (Y-axis positive direction) to slowly brought into contact with the workpiece 6 already turning at _one point P. Note coordinate x ₁ of the X-axis direction P ₁ point is pre-set, Y-axis direction of the coordinate is variable. The contact detection may be performed by the positional relationship deriving unit 23 by the method described above, but may also be performed by using the sensing data of the contact sensor. According to the above-mentioned contact detection method, the positional relationship deriving unit 23 generates a regression line from the change in the detected value after the contact and specifies the contact position after the fact. Therefore movement control unit 22, the moment that the tool edge has contacted with P ₁ point is still positional relationship deriving section 23 is not able to identify the contact position, the movement control unit 22 actually at _a point P is in contact, it is necessary to move the tool tip upwardly only slightly above _a point P (the correspondingly cutting is performed).

The positional relationship deriving section 23 derives the timing in contact with the regression line, provide movement control unit 22, coordinates of the timing of contact, i.e. the P ₁ point coordinates (x _{1, y 1)} to the position relationship deriving section 23 To do. Strictly speaking, the movement control unit 22 does not manage the coordinates of the cutting tool 11a of the cutting tool 11, but manages the coordinates of the cutting tool 11, but the coordinates of the cutting tool and the coordinates of the cutting tool are one-to-one. Since there is a relationship, the explanation will be given below based on the coordinates of the cutting edge.

As described above, as the work material 6, a material that has already been turned is used. This rotational axis of the workpiece 6, i.e. on the circumference of a circle having the same diameter centered on the axis of rotation of the main shaft 2a, detects a _point P, P ₂ point coordinates to be described later, and P ₃ point coordinates Because. Therefore, the positional relationship derivation unit 23 _{brings the tool cutting edge into contact with the turned work material 6 at P 1} point, but the coordinate values of the X-axis and the Y-axis at the time of the turning performed as the pre-machining are set. It is also possible to set P _{1 point.}

Subsequently, the movement control unit 22 lowers the tool cutting edge downward (in the negative direction of the Y axis in FIG. 11) by a sufficient distance, and advances the tool cutting edge in the positive direction of the X axis by a known distance d. Thereafter, the movement control unit 22 moves the tool cutting edge upward (Y-axis positive direction) to slowly brought into contact with the workpiece 6 at P ₂ points. Providing positional relationship deriving section 23 detects the contact and to derive the contact timing, the movement control unit 22, coordinates of the timing of contact, that is, P ₂ point coordinates (x _{2, y 2)} a positional relationship deriving section 23 To do.

Subsequently, the movement control unit 22 lowers the tool cutting edge downward (Y-axis negative direction) by a sufficient distance, and advances the tool cutting edge in the X-axis positive direction by a known distance d. The distance to be advanced may be a known distance, and may be different from the X-axis direction distance (d) between the _{P 1} point coordinate and the P _{2 point coordinate.} Thereafter, the movement control unit 22 moves the tool cutting edge upward (Y-axis positive direction) to slowly brought into contact with the workpiece 6 at _three points P. Providing positional relationship deriving section 23 detects the contact and to derive the contact timing, the movement control unit 22, coordinates of the timing of contact, i.e. the P ₃ points coordinates (x _{3, y 3)} the positional relationship deriving section 23 To do. Note that when performing contact detection while rotating the main shaft 2a, in order to reduce the radius of slightly cutting is performed at the time of contact, P ₁ point, each of the contact detection of P ₂ point and P ₃ points, different Z It is desirable to do this in the axial position.

The positional relationship deriving unit 23 is based on the coordinate values when the cutting tool 11 comes into contact with the cutting tool 11 at at least two positions different from the rotation angle position of the cutting tool 11 during turning, and the cutting tool 11 and the work material 6 are used. Determine the relative positional relationship with the center of rotation of. For example, when the coordinate values of the X-axis and the Y-axis during the turning process performed as the pre-machining are set to the P ₁ point, the positional relationship deriving unit 23 has the _{P 2} point and the P ₃ which are different rotation angle positions from the _{P 1 point.} Based on the coordinate values of the points, the relative positional relationship between the cutting tool 11 and the rotation center of the work material 6 is determined. Note Example positional relationship deriving section 23 in 1, three respective rotational angular positions different contact points, that is P ₁ point, P ₂ points, based on the coordinate values of P ₃ points, the cutting tool 11 and the workpiece Determine the relative positional relationship with the center of rotation of 6. The positional relationship deriving unit 23 calculates the coordinates (x, y) and radius R of the point A, which is the center of rotation of the work material 6, by utilizing the fact that the circle passing through the three points is determined to be one.

12 (a) and 12 (b) show the method of deriving the A point coordinates. As shown in FIG. 12A, the coordinates A can be obtained by calculating the intersection of the line L1 and the line L2. The lines L1 and L2 are represented by the following (Equation 5) and (Equation 6), respectively.

ここで、
ｘ_１−ｘ_２＝−ｄ
ｘ_２−ｘ_３＝−ｄ
であり、
Ｐ_２点座標（ｘ_２，ｙ_２）を（０，０）と定義すると、

と、Ａ点のｘ座標が導出される。 (Equation 7) is derived from (Equation 5) and (Equation 6).

here,
x ₁ −x ₂ = −d
x _2- x ₃ = -d
And
Defining P ₂ point coordinates _(x 2, _{y 2)} and (0,0),

Then, the x-coordinate of point A is derived.

（式９）に、（式８）で求めたｘを代入すると、

と、Ａ点のｙ座標が導出される。
なお、被削材６の回転半径は、以下のように求められる。

Further, the line L3 shown in FIG. 12B is represented by the following (Equation 9).

Substituting x obtained in (Equation 8) into (Equation 9)

Then, the y coordinate of point A is derived.
The radius of gyration of the work material 6 is obtained as follows.

Positional relationship deriving section 23, in this way, to derive the A point coordinates when the _{P 2} point coordinates _(x 2, _{y 2)} and (0,0). As a result, the positional relationship deriving unit 23 determines the relative positional relationship between the cutting tool 11 and the rotation center of the work material 6 based on the coordinate values of the three contact positions.

Hereinafter, the calculation accuracy of the A point coordinates and the radius R will be considered. With respect to FIG. 10, the contact position detection error e _p in contact detection was calculated, but in the following, _{the influence of this detection error e p} on the accuracy of the A point coordinate and the radius R will be verified.

として誤差を考える。 Let the x-coordinate error be e _x , the y-coordinate error be _ey , and the radius R error be e _R.
In other words

Consider the error as.

Considering the error in this way, the x-coordinate value of point A expressed by (Equation 8), the y-coordinate value of point A expressed by (Equation 10), and the radius R expressed by (Equation 11) are , Is expressed as follows.

ここで、

と近似できることから、誤差ｅ_ｘは、

と導出される。 When the error _xx is calculated,

here,

Since it can be approximated as, error _{e x} is,

Is derived.

ここで、

と近似できることから、誤差ｅ_ｙは、

と導出される。 Similarly, when the error _ey is calculated,

here,

Since it can be approximated as, the error _ey is

Is derived.

で表現される。 The error e _R is

It is expressed by.

Error e _x of the thus _{x-coordinate,} the error of the y-coordinate e _y, the error e _R radius R, either be expressed in the contact position detection error e _p, by reducing the contact position detection error e _p, processed It was confirmed that the accuracy could be improved.

As described in the first embodiment, if the relative position between the cutting tool 11 and the center of rotation (center of the spindle) of the work material 6 can be specified, it becomes possible to finish the cylindrical surface to an accurate diameter when machining the cylindrical surface, and the end face can be finished. Since the core height of the tool cutting edge does not deviate during machining, so-called dents do not remain, and high machining accuracy can be achieved even for spherical and aspherical machining.

<Example 2>
In the second embodiment, the positional relationship deriving unit 23 detects the contact between the cutting tool 11 and the reference surface provided on the part to which the work material 6 is attached, and specifies the relative position of the cutting tool 11 with respect to the part reference surface. You may. An example of the component may be, for example, a spindle 2a that supports the work material 6, and by bringing the cutting tool 11 into contact with a reference surface provided on the end surface or the peripheral surface of the spindle 2a, the positional relationship deriving unit 23 , The contact position between the cutting tool 11 and the spindle 2a may be specified, thereby deriving a relative positional relationship between the cutting tool 11 and the mounting surface, rotation center, or the like of the work material 6.

FIG. 13 is a diagram for explaining a reference plane. As the reference surface, a surface whose relative positional relationship with the mounting surface of the work W, the center of rotation, or the like is known is set. In this example, in a cutting device that rotates the work W around the central axis to perform turning, the end surface of the spindle 2b that fixes the work W is set as the reference surface 1, and the peripheral surface of the spindle 2b is set as the reference surface 2. That is, the reference surface 1 is a plane perpendicular to the spindle rotation axis, and the reference surface 2 is a cylindrical surface centered on the spindle rotation center. The positional relationship deriving unit 23 rotates the mounting surface and rotation of the cutting tool and the work W based on the coordinate values of the contact positions on the reference surface whose relative positional relationship with the mounting surface and rotation center of the work W is known. Determine the relative positional relationship with the center.

As described above, the positional relationship deriving unit 23 can detect the contact between the cutting tool 11 and the spindle 2b, which is a component, and specify the contact position.
Here, the positional relationship derivation unit 23 detects the contact of the tool cutting edge with respect to the reference surface 1, so that the tool cutting edge origin (the mounting surface of the work W, that is, the work W) in the length direction of the work W (left-right direction in the figure) The position of the tool edge relative to the leftmost surface of the tool) can be known accurately. As a result, when processing the end surface of the work W (the surface at the right end in the drawing), the length of the work W (length in the left-right direction) can be accurately finished.
Further, the positional relationship deriving unit 23 detects the contact of the tool cutting edge with respect to the reference surface 2 at three points (two points are sufficient if the diameter is known) having different Y-axis positions as in the first embodiment. , The origin of the tool cutting edge in the radial direction of the work W (the position of the tool cutting edge relative to the rotation center of the work W) can be accurately known. As a result, when machining the cylindrical surface of the work W, the diameter of the work W can be accurately finished.

The reference plane may be set as a part of the work W. For example, in FIG. 13, when the reference surface 1 is a part of the work W, the length from that surface to the right end surface of the work W can be accurately finished. Although an example of turning is shown in FIG. 13, in the case of planing, the plane can be specified by detecting contact at three points on the reference plane (accurate plane), so that the plane is parallel to the reference plane. Can be finished at an accurate height. Also, if the reference surface is a plane that is exactly perpendicular to the Z axis, a surface parallel to the bottom surface (the surface of the work W that is in contact with the reference surface) can be finished at an accurate height by detecting contact at one point. be able to.

と表現していることに留意されたい。
つまり、記号ｙの上にキャレット（ハット）を付したものと、同じ記号ｙの横にキャレットを付したものとは、同一の変数を示す。実施例でキャレット付きの記号は、求めるべき変数であることを意味する。なおキャレットを上に付した記号は数式中で使用され、キャレットを横に付した記号は文章中で使用される。また異なる実施例の図面で重複して用いられている記号は、それぞれの実施例の理解のために利用されることに留意されたい。 In the following Examples 3 to 13, a technique applying the three-point contact detection described in the first embodiment will be mainly described. In the drawings to be used in the following description, the A axis means a rotation axis centered on the X axis, the B axis means a rotation axis centered on the Y axis, and the C axis means a rotation axis centered on the Z axis. Further, in the present specification and drawings, regarding the symbol with a caret (hat), for example, when the symbol is "y", for convenience of notation,

Please note that it is expressed as.
That is, the one with a caret (hat) on the symbol y and the one with a caret next to the same symbol y indicate the same variable. The symbol with a caret in the embodiment means that it is a variable to be sought. The symbol with the caret on top is used in the formula, and the symbol with the caret on the side is used in the text. It should also be noted that the symbols used in duplicate in the drawings of different embodiments are used for understanding each embodiment.

<Example 3>
In the first embodiment, the control unit 20 determines the rotation center of the cutting tool 11 and the work material 6 based on the coordinate values of three points on the pre-processed work material 6 after the turning process. It identifies the relative positional relationship. In the third embodiment, the control unit 20 determines the relative positional relationship between the cutting tool 11 and the object having the known shape by using the object having the known shape machined with high precision for setting the origin of the cutting edge. The information about the cutting edge of the cutting tool 11 is specified. Hereinafter, the object used for specifying the information regarding the cutting edge of the cutting tool 11 is referred to as a "reference block". Since the control unit 20 identifies the cutting edge position by bringing the cutting edge of the cutting tool 11 into contact with the reference block, at least the shape of the reference block to be contacted is grasped as a premise.

FIG. 14 shows an example of a cutting device 1 in which a cutting tool 11 is rotatably attached to the C axis. FIG. 14A shows the state of the cutting device 1 as seen from the X-axis direction, and FIG. 14B shows the state of the cutting device 1 as seen from the Z-axis direction. The cutting tool 11 is supported by the support device 42, and the support device 42 is fixed to the mounting shaft 41 so that the C-axis can rotate.

A reference block 40, which is an object having a known shape, is arranged on the B-axis table 43. In the third embodiment, in order to specify the cutting tool 11 cutting edge position, the control unit 20 brings the cutting tool into contact with the reference block 40 at least three times, and uses the position coordinates of the contact point to mount the cutting tool 11. Identify information about. In the third embodiment, the feed mechanism 7 has a function of moving the B-axis table 43, and the movement control unit 22 moves the B-axis table 43 to move the cutting tool 11 cutting edge 11a and the known shape portion of the reference block 40. And are brought into contact with each other at multiple points. The reference block 40 is made of a high-hardness material so as not to be easily damaged by the contact of the cutting edge 11a. In the third embodiment, the nose radius of the cutting edge 11a, the center coordinates of the cutting edge roundness, and the error of the cutting edge shape are unknown, and a method for specifying these information will be described. Hereinafter, it is assumed that the tip of the cutting edge 11a has a constant curvature (nose radius), and the center of the roundness of the cutting edge may be referred to as a "tool center".

In the YZ plane shown in FIG. 14A, the nose radius R ^ and the tool center (z ^, y ^) in the YZ plane are obtained.
FIG. 15 shows how the cutting edge 11a and the known shape portion of the reference block 40 are in contact with each other at one point. As described above, the cutting edge 11a has a constant curvature and has an arcuate surface with a nose radius R ^. The nose radius R ^ is unknown. On the other hand, the reference block 40 comes into contact with the cutting edge 11a at a portion whose shape is known. When the shape is known in the third embodiment, it means that the positional relationship deriving unit 23 recognizes the shape of the portion where the cutting edge 11a may come into contact.

The reference block 40 may have a known shape at least at a portion that comes into contact with the cutting edge 11a, and the positional relationship deriving unit 23 does not need to recognize the shape of a portion that does not come into contact with the cutting edge 11a. .. In the example shown in FIG. 15, the reference block 40 has an arcuate surface having a radius Rw centered on the position indicated by “+”, and the positional relationship deriving unit 23 sets the origin of the cutting edge 11a when setting the origin. It is recognized that the cutting edge 11a comes into contact with the arc surface. In other words, when the origin is set, the movement control unit 22 controls the feed mechanism 7 to move the B-axis table 43 so that the cutting edge 11a comes into contact with the arc surface which is a known shape of the reference block 40. .. The shape data of the arc surface may be recorded in a memory (not shown).

The movement control unit 22 slowly moves the B-axis table 43 toward the cutting edge 11a of the cutting tool 11 from below to above (Y-axis positive direction). In FIG. 15, the cutting edge 11a and the reference block 40 are in contact with each other at the contact points indicated by ◯. The positional relationship derivation unit 23 defines the coordinates of the rotation center position “+” of the arc in the reference block 40 at this time as (0,0).

After that, the movement control unit 22 brings the reference block 40 into contact with the cutting edge 11a at a position moved by + ΔZ and −ΔZ in the Z-axis direction with reference to the first contact position. In any of these cases, the position of the reference block 40 in which the cutting edge 11a comes into contact is on an arcuate surface having a radius Rw. Specifically, the movement control unit 22 lowers the reference block 40 in the negative direction of the Y axis by a sufficient distance from the state shown in FIG. 15, then moves the reference block 40 in the negative direction of the Z axis by ΔZ, and moves the reference block 40 in the negative direction of the Z axis from that position in the positive direction of the Y axis. Move slowly to bring the arcuate surface of the reference block 40 into contact with the cutting edge 11a. The contact points at this time are indicated by Δ in the figure. Subsequently, the movement control unit 22 lowers the reference block 40 in the negative direction of the Y axis by a sufficient distance, moves the reference block 40 in the positive direction of the Z axis by 2ΔZ, and slowly moves the reference block 40 in the positive direction of the Y axis from that position to move the reference block 40 in the positive direction of the Y axis. The arcuate surface of the above is brought into contact with the cutting edge 11a. The contact points at this time are indicated by □ in the figure. In the second movement, the movement in the negative direction of the Y-axis may be omitted.

In this way, the movement control unit 22 brings the cutting edge 11a of the cutting tool 11 and the known shape portion of the reference block 40 into contact with each other at at least three points, and provides the coordinate value of the contact position to the positional relationship deriving unit 23. The positional relationship derivation unit 23 specifies information regarding the mounting position of the cutting tool 11 based on the coordinate values at the respective contact positions.

FIG. 16 shows the positional relationship between the cutting edge 11a and the reference block 40. In FIG. 15, when contact is made at the contact point indicated by □, the coordinates of the known arc center are (ΔZ, h ₂ ). h ₂ is a value detected by the movement control unit 22. Further, in the case of contact at the contact point indicated by Δ in FIG. 15, the coordinates of the known arc center are (−ΔZ, −h ₁ ). h _{1 is} also a value detected by the movement control unit 22.

連立すると、

As shown in FIG. 16, when the radial center of the arc surface in the reference block 40 at the time of the first contact is (0,0) and the tool center is (z ^, y ^),

When simultaneous,

R ^ is obtained using z ^ and y ^ obtained from the above equation.

As described above, the positional relationship deriving unit 23 specifies the information regarding the mounting position of the cutting tool 11 based on the coordinate values when they are in contact with each other at the three positions. Specifically, the positional relationship derivation unit 23 obtains the nose radius R of the cutting edge and the tool center coordinates (z, y) as information regarding the mounting position.

If the reference block 40 having a known arc shape is in contact with a point on the arc other than the above three contact positions at at least one point, the nose radius R and the tool center coordinates obtained as described above ( The deviation from the contact position predicted using z, y) is obtained as the deviation (error) of the tool cutting edge from the arc of the nose radius R.

Next, the positional relationship deriving unit 23 calculates the distance l ^ from the center of rotation of the C axis to the tip of the cutting edge 11a and the initial mounting angle θ ^ in the XY plane shown in FIG. 14 (b). For example, when processing a complicated free-form curved surface shape, a cutting feed performed by simultaneously controlling the XYC axes and a pick feed in the Z-axis direction may be repeated. When the C-axis is included in the cutting feed motion in this way, if there is an error between the distance l ^ from the center of rotation of the C-axis to the tip of the cutting edge 11a and the initial mounting angle θ ^, the machining accuracy will decrease. Therefore, the positional relationship deriving unit 23 specifies information regarding the mounting position of the cutting tool 11 based on the contact coordinate values of at least three points with the known shape portion of the reference block 40 when the cutting edge 11a is moved in the XY plane. To do.

FIG. 17 schematically shows an inclined state of the cutting tool 11 when the cutting tool 11 is rotated counterclockwise to bring the cutting edge 11a into contact with the upper surface (y reference surface) of the reference block 40. The movement control unit 22 controls the feed mechanism 7 to rotate the cutting tool 11 around the C axis. The upper surface of the reference block 40 is parallel to the vertical plane of the Y axis, and as shown in FIG. 14B, the position of the upper surface of the reference block 40 is known.

The movement control unit 22 slowly moves the B-axis table 43 toward the cutting edge 11a of the cutting tool 11 from below to above (Y-axis positive direction), and brings the upper surface of the reference block 40 into contact with the cutting edge 11a. After that, the movement control unit 22 lowers the reference block 40 in the negative direction of the Y axis by a sufficient distance, rotates the cutting tool 11 by ΔC in the counterclockwise direction, and then slowly rotates the reference block 40 in the positive direction of the Y axis. By moving, the upper surface of the reference block 40 is brought into contact with the cutting edge 11a. Subsequently, the movement control unit 22 lowers the reference block 40 in the negative direction of the Y axis by a sufficient distance, then rotates the cutting tool 11 further in the counterclockwise direction by ΔC, and then slowly rotates the reference block 40 in the positive direction of the Y axis. To bring the upper surface of the reference block 40 into contact with the cutting edge 11a. As a result, the positional relationship deriving unit 23 acquires the height (y position) in the Y-axis direction at the three contact positions.

_{FIG. 18 shows the height change Δy 1} of the contact position when the contact position is rotated by ΔC from the first contact position (initial y position). With the first contact position as a reference, the height change Δy ₂ of the contact position when further rotated by ΔC is used. At this time, the following equations hold for _{Δy 1} and Δy _2.

両式からｌ＾を消去させるよう連立させると、

得られたθ＾を用いてｌ＾を求めると、

When l ^ is deleted from both equations at the same time,

When l ^ is obtained using the obtained θ ^,

As described above, the positional relationship deriving unit 23 acquires information on the initial mounting position of the cutting tool 11 based on the coordinate values when the cutting tool 11 is in contact at the three positions with respect to the C-axis rotation. Specifically, the positional relationship deriving unit 23 derives the distance l from the C-axis rotation center to the cutting edge 11a and the initial mounting angle θ as information regarding the mounting position. As described above, in the third embodiment, by using the reference block 40, the positional relationship deriving unit 23 can specify the information regarding the mounting position with high accuracy.

<Example 4>
Also in the fourth embodiment, the control unit 20 uses an object (reference block 40) having a known shape machined with high precision for setting the origin of the cutting edge, and the relative position between the cutting tool 11 and the reference block 40. The relationship is defined to specify information about the mounting position of the cutting tool 11.

FIG. 19 shows another example of the cutting device 1 in which the cutting tool 11 is rotatably attached to the C axis. FIG. 19A shows the state of the cutting device 1 as seen from the X-axis direction, and FIG. 19B shows the state of the cutting device 1 as seen from the Z-axis direction. The cutting tool 11 is supported by the support device 42, and the support device 42 is fixed to the mounting shaft 41 so that the C-axis can rotate.

A reference block 40, which is an object having a known shape, is arranged on the B-axis table 43. Also in the fourth embodiment, in order to specify the cutting tool 11 cutting edge position, the control unit 20 contacts the cutting tool with the reference block 40 at least three times, and the cutting tool 11 is attached using the position coordinates of the contact point. Identify information about the location. In the fourth embodiment as well, the movement control unit 22 moves the B-axis table 43 to bring the cutting edge 11a of the cutting tool 11 into contact with the known shape portion of the reference block 40 at a plurality of points, as in the third embodiment.

First, a method for finding the tool center (x ^, y ^) in the nose radius R ^ and the XY plane will be described.
FIG. 20 shows a state in which the cutting edge 11a and the known shape portion of the reference block 40 are in contact with each other at one point. The cutting edge 11a has a constant curvature and has an arcuate surface with a nose radius R ^. The nose radius R ^ is unknown. The reference block 40 comes into contact with the cutting edge 11a at a portion whose shape is known. Note that the known shape means that the positional relationship deriving unit 23 recognizes the shape of a portion where the cutting edge 11a may come into contact with the cutting edge 11a.

In the example shown in FIG. 20, the reference block 40 has an arcuate surface having a radius Rw centered on the position indicated by “+”, and the positional relationship deriving unit 23 sets the origin of the cutting edge 11a when setting the origin. It is recognized that the cutting edge 11a comes into contact with the arc surface. In other words, when the origin is set, the movement control unit 22 controls the feed mechanism 7 to move the B-axis table 43 so that the cutting edge 11a comes into contact with the arc surface which is a known shape of the reference block 40. .. The shape data of the arc surface may be recorded in a memory (not shown).

The movement control unit 22 slowly moves the B-axis table 43 toward the cutting edge 11a of the cutting tool 11 from below to above (Y-axis positive direction). In FIG. 20, the cutting edge 11a and the reference block 40 are in contact with each other at the contact points indicated by ◯. The positional relationship derivation unit 23 defines the coordinates of the rotation center position “+” of the arc in the reference block 40 at this time as (0,0).

After that, the movement control unit 22 brings the reference block 40 into contact with the cutting edge 11a at a position moved by + ΔX and −ΔX in the X-axis direction with reference to the first contact position. In any of these cases, the position of the reference block 40 in which the cutting edge 11a comes into contact is on an arcuate surface having a radius Rw. Specifically, the movement control unit 22 lowers the reference block 40 in the negative direction of the Y axis by a sufficient distance from the state shown in FIG. 20, then moves the reference block 40 in the negative direction of the X axis by ΔX, and moves the reference block 40 in the negative direction of the X axis from that position in the positive direction of the Y axis. Move slowly to bring the arcuate surface of the reference block 40 into contact with the cutting edge 11a. The contact points at this time are indicated by Δ in the figure. Subsequently, the movement control unit 22 lowers the reference block 40 in the negative direction of the Y-axis by a sufficient distance, moves the reference block 40 in the positive direction of the X-axis by 2ΔX, and slowly moves the reference block 40 in the positive direction of the Y-axis from that position to move the reference block 40 in the positive direction of the Y-axis. The arcuate surface of the above is brought into contact with the cutting edge 11a. The contact points at this time are indicated by □ in the figure. In the second movement, the movement in the negative direction of the Y-axis may be omitted.

In this way, the movement control unit 22 brings the cutting tool 11's cutting edge 11a into contact with the known shape portion of the reference block 40 at at least three points, and provides the coordinate value of the contact position to the positional relationship deriving unit 23. The positional relationship derivation unit 23 specifies information regarding the mounting position of the cutting tool 11 based on the coordinate values at the respective contact positions.

FIG. 21 shows the positional relationship between the cutting edge 11a and the reference block 40. In FIG. 20, when contact is made at the contact point indicated by □, the coordinates of the known arc center are (ΔX, h ₂ ). h ₂ is a value detected by the movement control unit 22. Further, in the case of contact at the contact point indicated by Δ in FIG. 20, the coordinates of the known arc center are (−ΔX, −h ₁ ). h _{1 is} also a value detected by the movement control unit 22.

連立すると、

As shown in FIG. 21, when the radial center of the arc surface in the reference block 40 at the time of the first contact is (0,0) and the tool center is (x ^, y ^),

When simultaneous,

R ^ is obtained using x ^ and y ^ obtained from the above equation.

As described above, the positional relationship deriving unit 23 specifies the information regarding the mounting position of the cutting tool 11 based on the coordinate values when they are in contact with each other at the three positions. Specifically, the positional relationship deriving unit 23 obtains the nose radius R of the cutting edge and the tool center coordinates (x, y) as information regarding the mounting position.

Next, the positional relationship derivation unit 23 obtains the z coordinate of the cutting edge 11a.
FIG. 22 shows a state in which a portion of the reference block 40 having a known shape is in contact with the cutting edge 11a of the cutting tool 11. The positional relationship derivation unit 23 identifies the tip point of the cutting edge by acquiring the z-coordinate value at this time.

The movement control unit 22 needs to move the reference block 40 so that the known arc surface of the reference block 40 and the cutting edge 11a come into contact with each other. For example, when the reference block 40 is moved, the arc surface of the reference block 40 may come into contact with the rake face of the cutting tool 11 before it comes into contact with the cutting edge 11a. In the illustrated example, when the angle of the rake face in the initial mounting state is less than 90 degrees with respect to the Z axis, the arc surface of the reference block 40 and the cutting tool 11 may be affected depending on the position of the reference block 40 in the Z axis direction. The arc surface of the reference block 40 may not come into contact with the cutting edge 11a due to contact with the rake face. At this time, the movement control unit 22 preferably shifts the reference block 40 in the negative direction of the Y axis so that the cutting edge 11a comes into contact with the upper side of the known arc surface.

As described above, in the fourth embodiment, by using the reference block 40, the positional relationship deriving unit 23 can specify the information regarding the mounting position with high accuracy.

<Example 5>
If the cutting tool 11 has a mounting error, the work material 6 after cutting will have a shape different from the originally planned shape. Therefore, in the fifth embodiment, the difference between the machined surface of the work material 6 actually turned and the machined surface of the work material 6 when it is ideally turned (that is, the designed machined surface) is used. Then, the mounting error (Δx ^, Δy ^, Δz ^) at the center of the tool is specified. If the mounting error at the center of the tool can be specified, the feed path of the cutting tool 11 with the specified mounting error corrected can be calculated. In the fifth embodiment, the movement control unit 22 moves the cutting tool 11 relative to the work material 6 after the cutting by using the feed function by the feed mechanism 7 in the movement direction which was not used during the cutting. Then, the mounting error of the tool cutting edge is specified based on the coordinate values when the cutting tool 11 comes into contact with the cutting tool 11 at at least two positions.

Hereinafter, the machined surface of the work material 6 that has been turned to derive an error may be referred to as a “pre-machined surface” or a “ready-processed surface”. By forming the pre-processed surface thicker than the final finished surface, it is possible to perform the finishing process with the corrected feed path when the final finished surface is processed. That is, after the intermediate finishing process before the final finishing process, the mounting error may be specified by using the processed surface.

The control unit 20 obtains the mounting error of the cutting tool 11 based on the coordinate values of at least three points on the pre-machined surface of the work material 6. When using the coordinate value of one point acquired at the time of cutting the pre-machined surface, the control unit 20 puts the cutting tool 11 on the pre-machined surface at a position different from the rotation angle position of the cutting tool 11 at the time of turning. The mounting error of the cutting tool 11 may be obtained by acquiring the coordinate values of at least two points in contact with each other. That is, the control unit 20 may acquire the coordinate values of at least two points where the cutting tool 11 is brought into contact with the pre-machined surface at different y positions to obtain the mounting error of the cutting tool 11.

Considering the possibility that the accuracy of the coordinate value acquired at the time of pre-machining and the coordinate value acquired by contacting the pre-machining surface may be slightly different, the control unit 20 uses the coordinate value acquired at the time of pre-machining. Instead, the mounting error of the cutting tool 11 may be obtained by using the coordinate values of at least three points in which the cutting tool 11 is brought into contact with the pre-machined surface at different y positions.

As described in the first embodiment, when the contact point coordinate value is acquired, the work material 6 may be rotated from the viewpoint of preventing the cutting edge 11a from being damaged. In this case, since the contact points are slightly grooved, it is preferable to slightly shift the z positions within a range that can be regarded as substantially the same when acquiring the next contact point coordinate values. In the following, an example in which the control unit 20 obtains the mounting error using the coordinate values of three points is shown, but in order to improve the detection accuracy of the mounting error, the coordinate values of four or more points may be used.

FIG. 23A shows how the work material 6 is processed so as to have a shape having a cylindrical surface and a hemispherical surface. The work material 6 is rotatably supported by the mounting shaft 41. In the fifth embodiment, the cutting tool 11 is attached to the cutting device 1 with an attachment error (Δx ^, Δy ^, Δz ^).
FIG. 23B shows mounting errors (Δx ^, Δz ^) in the ZX plane. C2 indicates the ideal tool center position, and C1 indicates the tool center position including an error. FIG. 23 (c) shows mounting errors (Δx ^, Δy ^) in the XY plane.

In FIG. 23A, the feed path indicated by the arrow is the path through which the ideal center C2 passes. In the NC machine tool, the feed path is calculated on the assumption that the tool center is at C2. The movement control unit 22 processes the work material 6 with the cutting tool 11 by utilizing the feed function in the Z-axis translational direction and the feed function in the C-axis rotation direction by the feed mechanism 7. In FIG. 23 (a), the dotted line indicates the ideal machined surface when the tool center is at C2. In this turning process, it is defined as a design value to process a cylindrical surface having a radius Rw.

However, when the actual tool center is in C1 including the mounting error, when the movement control unit 22 moves the cutting tool 11 according to the calculated feed path, the machined surface shown by the solid line is formed. ..

FIGS. 24A and 24B are diagrams for explaining a method for deriving the mounting error (Δx ^, Δy ^) at the center of the tool. Due to the mounting error (Δx ^, Δy ^) on the XY plane, the radius of the cylindrical surface is rw'instead of Rw. The movement control unit 22 moves the cutting tool 11 relative to the work material 6 after cutting by using the feed function of the feed mechanism 7 in the moving direction, which was not used during cutting, to cut. The coordinate values when the tool 11 comes into contact with each other at at least two positions are acquired. In the fifth embodiment, the movement control unit 22 acquires a plurality of contact coordinate values by using the feed functions in the X-axis translation direction and the Y-axis translation direction by the feed mechanism 7.

Even if the cutting tool 11 is brought into contact with the pre-machined surface by using the feed function of the feed mechanism 7 in the same moving direction as in the pre-machining, the cutting tool 11 is theoretically in contact with the same coordinate position as in the pre-machining. Therefore, in the fifth embodiment, in order to derive the mounting error of the tool center by the contact between the pre-machined surface and the cutting tool 11, the feed in the moving direction is different from the feed function by the feed mechanism 7 in the moving direction used in the pre-machining. The cutting tool 11 is brought into contact with the pre-machined surface by utilizing the function. That is, the contact position of the cutting tool 11 is derived by using a feed function other than the feed function in the moving direction required at the time of pre-machining. As described above, the movement control unit 22 uses the ZC-axis feed function during pre-machining, but acquires the contact point coordinates by using the XY-axis feed function during the mounting error estimation process.

As described in the first embodiment, the positional relationship deriving unit 23 acquires the coordinate values of the three points on the cylindrical surface.
In the figure, □ represents a point on the cylindrical surface.
Point 1: (Rw + Δx ^, Δy ^)
Point 2: (Rw + Δx ^ −Δx ₁ , −ΔY + Δy ^)
Point 3: (Rw + Δx ^ −Δx ₂ , -2ΔY + Δy ^)
Will be. Δx ₁ and Δx ₂ are values detected by the movement control unit 22.

In this example, the coordinate value shown as point 1 uses the coordinate acquired at the time of preprocessing, but the movement control unit 22 brings the cutting edge 11a into contact with the cylindrical surface at three points, and the coordinate value of the three points. May be obtained. At this time, from the viewpoint of preventing the cutting edge 11a from being damaged, when the work material 6 is rotated, the movement control unit 22 contacts the cutting edge 11a at different z positions on the cylindrical surface to obtain three contact coordinate values. It is preferable to obtain it.

以上のように、位置関係導出部２３は（Δｘ＾，Δｙ＾）を導出できる。 The positional relationship derivation unit 23 performs the following calculation.

As described above, the positional relationship derivation unit 23 can derive (Δx ^, Δy ^).

As described in the second embodiment, the mounting error Δz ^ in the Z-axis direction may be derived by the positional relationship deriving unit 23 using, for example, the reference plane of the mounting shaft 41. From the above, the mounting error (Δx ^, Δy ^, Δz ^) at the center of the tool is specified. As described above, in the fifth embodiment, the mounting error (Δx ^, Δy ^, Δz ^) at the center of the tool is specified by using the difference between the pre-machined surface and the target design machined surface, and the movement control unit. 22 can recalculate the feed path corrected for the mounting error.

<Example 6>
In the sixth embodiment, a method for measuring the shape collapse of the cutting edge 11a will be described.
As described in the third embodiment, the cutting edge 11a may have irregularities. Therefore, in the following, a method of measuring the unevenness of the pre-machined surface to which the shape of the cutting edge is transferred and identifying the shape error of the tool cutting edge from the unevenness of the machined surface will be shown. In the sixth embodiment, when the shape error due to the shape error factor other than the shape collapse of the cutting edge can be estimated, it is assumed that the feed motion by the feed mechanism 7 in the moving direction, which was not used in the cutting process, is accurate. Since the shape of the machined surface is measured using one cutting edge point, the shape error of the tool cutting edge is specified by the difference between the estimated position of each point on the pre-machined surface and the detected position. In the sixth embodiment, the movement control unit 22 moves the cutting tool 11 relative to the work material 6 after the cutting by using the feed function by the feed mechanism 7 in the movement direction which was not used during the cutting. Then, the mounting error of the tool cutting edge is specified based on the coordinate values when the cutting tool 11 comes into contact with the cutting tool 11 at at least two positions.

FIG. 25A shows a state in which a hemispherical surface is processed. The movement control unit 22 processes the work material 6 with the cutting tool 11 by utilizing the feed function in the X-axis and Z-axis translational directions and the feed function in the C-axis rotation direction by the feed mechanism 7. FIG. 25A shows a state in which machining is performed with an ideal feed path without a mounting error at the center of the tool. If there is a mounting error at the center of the tool, measure the mounting error (Δx ^, Δy ^, Δz ^) as described in Example 5 before estimating the shape error of the tool cutting edge. Is desirable. In the following, the positional relationship deriving unit 23 estimates the shape error of the cutting edge from the deviation from the ideal shape of the pre-machined surface of the hemisphere.

As shown in FIG. 25 (a), in this spherical surface machining, turning is performed without rotating the cutting tool 11 on the B axis. With reference to FIGS. 25 (a) and 25 (c), the shape of the point A of the cutting edge 11a is transferred to the shape of the point a in the work material 6, and the shape of the point B of the cutting edge 11a is the shape of the work material 6. It is transferred to the shape of point b, and the shape of point C of the cutting edge 11a is transferred to the shape of point c in the work material 6. In this way, the shape of the cutting edge 11a from A to C is transferred to the pre-processed surface of the work material 6 from a to c.

At this time, if the shape from A to C has an ideal arc shape, the cross section of the spherical surface to be machined has an ideal arc shape. However, as shown in FIG. 25 (c), when the cutting edge 11a has irregularities, the irregularities are transferred to the machined surface of the work material 6.

FIG. 25B shows a state in which the spherical shape of the work material 6 is measured. The movement control unit 22 acquires a plurality of contact coordinate values by using the feed function in the Y-axis and Z-axis translation directions by the feed mechanism 7. After aligning the center of the tool with the center of rotation of the C-axis, the movement control unit 22 moves the cutting edge 11a toward the origin of the hemisphere while shifting θn without changing the x position (x = 0), and at a plurality of points. Make contact. By reducing the shift amount of θn, a large number of contact points can be obtained. The positional relationship derivation unit 23 specifies the shape of the arc on the spherical surface at x = 0 by acquiring the coordinates of a plurality of contact points. By acquiring the actual spherical shape of the work material 6, the positional relationship deriving unit 23 can acquire the amount of deviation from the estimated spherical shape, and therefore can derive the collapsed shape of the cutting edge 11a. FIG. 25 (d) shows that the detected values of the amount of deviation of the spherical surface at θn are Δr _{w, n} . At this time, the radial collapse at the cutting edge 11a is ΔRn ^ (= −Δr _{w, n} ) ( (See FIG. 25 (c)). In this way, the positional relationship deriving unit 23 can measure the shape of the cutting edge.

According to the sixth embodiment, the movement control unit 22 uses the feed function in the Y-axis translation direction, which was not used during the cutting process, with respect to the work material 6 after cutting, so that the positional relationship deriving unit 23 However, the profile of the cutting edge shape can be specified from the amount of deviation from the position where it should be in contact if it has an ideal shape. The positional relationship deriving unit 23 specifies the profile of the cutting edge shape, so that the movement control unit 22 can calculate the feed path in consideration of the profile of the cutting edge shape. Alternatively, when it is presumed that other machining error factors are small, the tool movement path may be directly corrected by the shape error measured in Example 6 to perform final finishing machining.

<Example 7>
In the fifth embodiment, a method of deriving the mounting error (Δx ^, Δy ^, Δz ^) at the center of the tool when the cutting tool 11 has a mounting error has been described. In the seventh embodiment, a method for deriving these errors will be described when the cutting tool 11 has not only mounting errors but also errors in the feeding direction of the tools.

Also in the seventh embodiment, the movement control unit 22 relatives the cutting tool 11 to the work material 6 after the cutting process by utilizing the feed function by the feed mechanism 7 in the moving direction which was not used during the cutting process. By moving the cutting tool 11, the mounting error of the cutting tool edge is specified based on the coordinate values when the cutting tool 11 comes into contact with the cutting tool 11 at at least two positions.

FIG. 26A shows a state when the cutting tool 11 is moved in the Z-axis direction for pre-machining. The movement control unit 22 processes the work material 6 with the cutting tool 11 by utilizing the feed function in the Z-axis translational direction and the feed function in the C-axis rotation direction by the feed mechanism 7. In this turning process, when the cutting tool 11 was sent along the line L1 parallel to the Z-axis, the mounting error of the tool center described in the fifth embodiment existed, and the Z-axis and the C-axis rotation center. Due to the fact that they were not parallel, a machining error occurred in the target cylindrical surface. As for the line L1, in the NC machine tool, the feed path of the cutting tool 11 was calculated on the assumption that the line L1 is along the Z axis and therefore parallel to the center of rotation of the C axis. Since the center of rotation of the C-axis and the center of rotation of the C-axis were not actually parallel to each other, the movement control unit 22 moves the cutting edge 11a along the path indicated by the solid line arrow as the feed path. Therefore, a pre-processed surface having a shape different from the target is created.

Regarding the error factors of this parallelism, in addition to the assembly error at the time of manufacturing the machine tool, the deformation due to the weight distribution change at the time of installation, the movement of the feed mechanism, and the mounting of the work material, the deformation due to the machining force, the temperature / machining Thermal deformation due to heat is conceivable. Among these, when considering the deformation due to the machining force, it is desirable to set the machining conditions so that the machining force becomes the same at the time of pre-machining and the final finishing machining.

In the error derivation process, the movement control unit 22 acquires a plurality of contact coordinate values by using the feed functions of the feed mechanism 7 in the X-axis translation direction, the Y-axis translation direction, and the Z-axis translation direction. The movement control unit 22 derives the contact coordinate value of the cutting edge 11a when the y position is changed at each of the z positions Z1 and Z2 and the blade edge 11a is moved three times in the x direction. By deriving the contact coordinate values of the three points, as described in the fifth embodiment, the amount of misalignment from the ideal tool center position (Δx ^ ₁ , Δy ^ ₁ ), (Δx ^ ₂ , Δy ^ ₂₎ ) Is derived.

したがって、

となる。なお、ここでは２つのＺ位置での位置ずれを線形補間したが、３つ以上のＺ位置での位置ずれを測定して補間の次数を上げても良い。 The positional relationship derivation unit 23 can calculate the trajectory of the feed path by deriving _{(Δx ^ 1} , Δy ^ ₁ , Z1) and (Δx ^ ₂ , Δy ^ _{2, Z2).} Here, assuming that the position error expected to have relative to the center of rotation of the C axis at an arbitrary z is (Δx ^, Δy ^),

Therefore,

Will be. Here, the positional deviation at the two Z positions is linearly interpolated, but the positional deviation at three or more Z positions may be measured to increase the degree of interpolation.

As described above, according to the seventh embodiment, the movement control unit 22 uses the feed function in the translational direction of the X-axis and the Y-axis, which was not used during the cutting process, with respect to the work material 6 after cutting. The parallelism of the cutting tool 11 with respect to the C-axis in the feeding direction can be estimated from the amount of deviation from the position where the positional relationship deriving unit 23 should be in contact with the ideal shape. In the seventh embodiment, by estimating the parallelism of the cutting tool 11 in the feeding direction with respect to the C axis, the positional relationship deriving unit 23 can specify the deviation of the cutting tool 11 in the relative moving direction with respect to the work material 6. By obtaining the position error at an arbitrary z as shown by the above equation, the movement control unit 22 can calculate the feed path corrected for this position error.

<Example 8>
FIG. 27 shows a state when the cutting tool 11 is moved in the X-axis direction and the Z-axis direction to preprocess the spherical surface. In this turning process, where the X-axis should be orthogonal to the C-axis, the orthogonality is broken, so that a machining error occurs in the spherical surface. In the NC machine tool, when the feed path which is the line L2 for machining the spherical surface was calculated with the X axis as a reference, the X axis for tool control and the C axis which is the rotation axis of the work material 6 were calculated. Since the orthogonality is broken, the movement control unit 22 moves the cutting edge 11a along the path indicated by the solid line arrow as the feed path.

このように直交度を示すθ＾が求まれば、移動制御部２２は、このθ＾を０とする工具の送り経路を算出して補正する。
なお、この手法は、球面以外の面（平面や非球面を含む）に対しても適用可能である。 In the error derivation process, the movement control unit 22 brings the cutting edge 11a into contact with a certain machining point P1 at a point P2 symmetrical with respect to the C axis. From the difference between the moving distance (2ΔX) in the X direction and the detected value (Δz) in the Y direction at this time, θ ^ indicating the degree of orthogonality between the C axis and the X axis can be obtained by the following equation.

When θ ^ indicating the degree of orthogonality is obtained in this way, the movement control unit 22 calculates and corrects the feed path of the tool with θ ^ as 0.
Note that this method can also be applied to surfaces other than spherical surfaces (including flat surfaces and aspherical surfaces).

Also in the eighth embodiment, the movement control unit 22 relatives the cutting tool 11 to the work material 6 after the cutting process by utilizing the feed function by the feed mechanism 7 in the moving direction which was not used during the cutting process. By moving the cutting tool 11, the mounting error of the cutting tool edge is specified based on the coordinate values when the cutting tool 11 comes into contact with the cutting tool 11 at at least two positions.
As described above, in the eighth embodiment, by estimating the degree of orthogonality of the X-axis with respect to the C-axis, the positional relationship deriving unit 23 can specify the amount of deviation of the cutting tool 11 with respect to the work material 6 in the relative moving direction.

<Example 9>
In Example 5, the mounting error (Δx ^, Δy ^, Δz ^) at the center of the tool was estimated using the coordinate values when the cutting edge 11a was brought into contact with the cylindrical surface. In the ninth embodiment, a method of estimating the mounting error (Δx ^, Δy ^, Δz ^) of the tool center by using the coordinate values when the cutting edge 11a is brought into contact with the pre-machined spherical surface will be described. The pre-processed spherical surface may be, for example, a work material 6 shown in FIG. 23 excluding the cylindrical surface. The movement control unit 22 pre-machines the work material 6 with the cutting tool 11 by utilizing the feed function in the X-axis translation direction, the feed function in the Z-axis translation direction, and the feed function in the C-axis rotation direction by the feed mechanism 7. ..

In the method shown in the ninth embodiment, the movement control of the cutting edge 11a is performed so that the cutting edge 11a is brought into contact with three points at the same Z position. In the error derivation process, the movement control unit 22 acquires a plurality of contact coordinate values by using the feed functions of the feed mechanism 7 in the X-axis translation direction, the Y-axis translation direction, and the Z-axis translation direction.

FIG. 28A shows how the cutting edge 11a is processing P1. The tool center coordinates on the NC machine tool are known and are (X ₁ , 0, Z ₁ ). The angle of the line segment connecting the geographic _{center Occ} and P1 with respect to the XY plane _{is θ 1} . Assuming that the nose radius of the cutting edge 11a is R, the coordinates of P1, which is also the machining point, are
P1: (X ₁ −Rcosθ ₁ , 0, Z ₁ −Rsinθ ₁ )
Will be.

When the coordinates of P1 are determined, they are in the same Z position (Z _{1 −} Rsinθ ₁ ) as P1 (see FIG. 28 (b)), and are displaced from P1 by ΔY and 2ΔY in the negative direction of the Y axis (FIG. 28 (c)). (See), set P2 and P3 to be in contact. Further, the angle between the line segment connecting the C-axis rotation center and P1 and the line segment connecting the C-axis rotation center and P2 in the XY plane is α, and the line segment connecting the C-axis rotation center and P1 and the C-axis rotation center and P3 Let β be the angle of the line segment connecting the two (see FIG. 28 (b)).
FIG. 29 shows the angle of the line segment connecting the geographic _{center Occ and the contact point with respect to the XY plane.} Here, the angle of the line segment with P2 is θ ₂ , and the angle of the line segment with P ₃ is θ 3.
Therefore, the tool center coordinates (C2) for contacting P2 and the tool center coordinates (C3) for contacting P3 are calculated as follows.
C2: (X ₂ + Rcosθ ₂ , −ΔY, Z ₁ −Rsinθ ₁ + Rsinθ ₂ )
C3: (X ₃ + Rcosθ ₃ , -2ΔY, Z _1- Rsinθ ₁ + Rsinθ ₃ )

各座標値の原点はＯcであり、ＯcはＣ軸回転中心線上にあって、加工点の軌跡（円弧であって、ＸＺ面に平行な平面上にある）の中心（工具取付誤差がある場合、その分、Ｃ軸回転中心線からずれている）と同じｚ座標値を持つ点である。 The positional relationship derivation unit 23 calculates _{X 2} , X ₃ , α, β, θ ₁ , θ ₂ , and θ _{3 by the following geometrical relational expressions.}

The origin of each coordinate value is Oc, which is on the C-axis rotation center line and the center of the locus of the machining point (which is an arc and is on a plane parallel to the XZ plane) (when there is a tool mounting error). , The point deviates from the C-axis rotation center line by that amount) and has the same z-coordinate value.

The movement control unit 22 brings the cutting edge 11a into contact with P2 and P3. At this time, the movement control unit 22 adjusts the (y, z) of the center coordinates of the cutting edge 11a to the above coordinate values of C2 and C3, respectively, and then moves in the X direction to bring the cutting edge 11a into contact with the spherical surface. At this time, if the contact is made with the same x-coordinate value as the calculated value, it is determined that there is no mounting error of the center coordinates. On the other hand, if the contact is made at the x position of the tool center on the NC machine tool, which is different from the calculated value, the amount of movement in the X direction is detected as an error.

Detection C2: (X ₂ + Δx ₂ + Rcosθ ₂ , −ΔY, Z ₁ −Rsinθ ₁ + Rsinθ ₂ )
Detection C3: (X ₃ + Δx ₃ + Rcosθ ₃ , -2ΔY, Z ₁ −Rsinθ ₁ + Rsinθ ₃ )
[Delta] x _2, [Delta] x ₃ is the detection value.

From the detected values, P2 and P3 can be approximately derived as follows.
Detection P2: (X ₂ + Δx ₂ , −ΔY, Z ₁ −Rsinθ ₁ )
Detection P3: (X ₃ + Δx ₃ , -2ΔY, Z ₁ −Rsinθ ₁ )
Regarding the error of the z position, the tool nose radius is generally smaller than the machining surface radius, and even if there is a mounting error, the locus shape of the machining point (on a plane parallel to the XZ plane) is the mounting error. Since the curvature seen in the Y direction is correct only by translating (the curvature seen in the XY cross section in the Z direction has an error), the deviation of the z position is smaller than that of the x position. Therefore, the deviation of the z position can be ignored.

FIG. 30 (a) shows the relationship between the imaginary circle formed by using the initial circle formed by P1, P2, P3, the error derived from the initial yen (Δx _2, Δx _3). The virtual circle passes through P1, detection P2, and detection P3. (Δx', Δy') is the center of the virtual circle.
FIG. 30B shows a coordinate system in which the center coordinates of the virtual circle are returned to the origin. At this time, the tool mounting error (Δx ^, Δy ^) is estimated by the following equation.
(Δx ^, Δy ^) = (−Δx', −Δy')

The positional relationship deriving unit 23 uses the estimated tool mounting error (Δx ^, Δy ^) and uses the following geometrical relationship equations to obtain X ₂ , X ₃ , α, β, and θ ₁ (first). the contact points, remains the same as during processing, does not change with time of the first contact. Accordingly X1, Z1 and similarly θ1 no changes in may not necessarily be recalculated), theta _2, the theta ₃ again calculate.

As a result, C2: (X ₂ −Δx ^ + Rcosθ ₂ , −ΔY, Z ₁ −Rsinθ ₁ + Rsinθ ₂ )
C3: (X ₃ −Δx ^ + Rcosθ ₃ , -2ΔY, Z ₁ −Rsinθ ₁ + Rsinθ ₃ )
Is derived.

The movement control unit 22 brings the cutting edge 11a into contact with the new P2 and P3 by using the derived C2 and C3. The movement control unit 22 adjusts the (y, z) of the center coordinates of the cutting edge 11a to the above coordinate values of C2 and C3, respectively, and then moves the cutting edge 11a in the X direction to bring the cutting edge 11a into contact with the spherical surface. At this time, if the contact is made at the same center coordinates as the calculated value, it is determined that there is no estimation error in the estimated value of the mounting error of the center coordinates. By repeating this process, the cutting edge 11a comes into contact with the spherical surface of the work material 6 at the center coordinates that can be regarded as the same as the calculated value, that is, the estimation error becomes sufficiently small, and an accurate mounting error can be obtained. Desired.

Also in the ninth embodiment, the movement control unit 22 relatives the cutting tool 11 to the work material 6 after the cutting process by utilizing the feed function by the feed mechanism 7 in the moving direction which was not used during the cutting process. By moving the cutting tool 11, the mounting error of the cutting tool edge is specified based on the coordinate values when the cutting tool 11 comes into contact with the cutting tool 11 at at least two positions.
As described above, in the ninth embodiment, the mounting error (Δx ^, Δy ^, Δz ^) at the center of the tool is specified by converging the difference between the pre-machined spherical surface and the target design machined surface by iterative calculation. To do.

<Example 10>
In Examples 5 to 9, turning without rotating the cutting tool 11 on the B axis has been described, but in Example 10, processing in which the cutting tool 11 is rotated on the B axis and only one point of the cutting edge 11a is used will be described.
FIG. 31A shows how one point of the cutting edge 11a is used for cutting during machining. In such a process, resulting in a machining error is an error in the mounting position relative tool center C to B axis center O _B.
FIG. 31 (b) the distance L ^ between the B axis center O _B of the tool center C, is an explanatory view for obtaining the initial mounting angle theta ^. As shown in the figure, the movement control unit 22 changes the mounting angles by + ΔB and −ΔB at predetermined y-coordinates and z-coordinates, and detects _{increments Δx 1} and Δx _{2 of the x-coordinate at the contact point of the cutting edge 11a.} , The calculation is performed using these as shown in the following equation.

以上により、Ｂ軸回転中心に対する相対的な工具中心Ｃの取付位置である、距離Ｌ＾と角度θ＾が求められる。

From the above, the distance L ^ and the angle θ ^, which are the mounting positions of the tool center C relative to the B-axis rotation center, can be obtained.

<Example 11>
In the eleventh embodiment, the error of the center of rotation of the C axis is first identified by using the pre-processed surface obtained by the scanning line processing. Also in the eleventh embodiment, the error of the relative C-axis rotation center position seen from the tool center is identified by bringing the cutting edge 11a into contact with the premachined surface at a plurality of points and deriving the difference from the ideal profile. To do.

FIG. 32 conceptually shows the cutting feed direction in the XZ plane and the pick feed direction in the YZ plane in scanning line machining. In order to identify the error of the center of rotation of the C axis, the shape of the workpiece in the YZ plane and the shape of the workpiece in the XZ plane can be used.

<Use of the shape of the workpiece in the YZ plane>
FIG. 33A shows the state of the cutting edge 11a during machining. In FIG. 33A, the dotted line represents the cutting motion profile of the tool center during machining, and the solid line represents the pre-machined surface profile. Ideal tool-centered cutting motion profiles and pre-machined surface profiles are known.
In FIG. 33B, the C-axis (here, the C-axis is attached to the tool side) is rotated 90 degrees from the posture at the time of machining, and then the cutting edge 11a is brought into contact with the pre-machined surface at a plurality of points. Show how it is. In FIG. 33 (b), the solid line represents the contact surface profile connecting the contact points.

The positional relationship derivation unit 23 identifies the Y-direction error of the C-axis rotation center (X-direction error after C-axis rotation and before rotation) by numerical analysis so that the contact surface profile and the pre-machined surface profile fit best. .. Specifically, the positional relationship derivation unit 23 estimates each contact position from the pre-machined surface profile, derives an error from the actual contact detection position, and rotates the C-axis so that the sum of the errors is minimized. Identify the center coordinates.

<Use of the shape of the workpiece in the XZ plane>
FIG. 34A shows the state of the cutting edge 11a during machining. In FIG. 34 (a), the dotted line represents the cutting motion profile of the tool center during machining, and the solid line represents the pre-machined surface profile. Ideal tool-centered cutting motion profiles and pre-machined surface profiles are known.
FIG. 34B shows a state in which the cutting edge 11a is brought into contact with the pre-machined surface at a plurality of points after the C-axis is rotated by 90 degrees from the posture at the time of machining. In FIG. 34 (b), the solid line represents the contact surface profile connecting the contact points.

The positional relationship derivation unit 23 identifies the X-direction error (the Y-direction error after C-axis rotation and before rotation) of the C-axis rotation center by numerical analysis so that the contact surface profile and the pre-machined surface profile fit best. .. Specifically, the positional relationship derivation unit 23 estimates each contact position from the pre-machined surface profile, derives an error from the actual contact detection position, and rotates the C-axis so that the sum of the errors is minimized. Identify the center coordinates.

As shown in FIG. 33 (b) or FIG. 34 (b), the relative C-axis rotation center position as seen from the tool center is identified. Once the C-axis rotation center position is identified, the shape error of the cutting edge 11a can be measured by using it.
FIG. 35 shows a method for measuring the cutting edge shape error. The movement control unit 22 rotates the C-axis by 90 degrees from the posture at the time of machining, and brings the cutting edge 11a into contact with the cutting edge 11a on the pre-machined surface at a plurality of points along a curve so that the same cutting edge position contacts. FIG. 35 shows how the cutting edge contacts the pre-processed surface at the lowest point in the Z direction along the ridge indicated by the broken line. The positional relationship deriving unit 23 measures the collapse of the cutting edge shape from the calculated contact position at each contact point and the amount of deviation of the detected contact position in the same manner as in the sixth embodiment.

<Example 12>
In Example 12, the error of the center of rotation of the C-axis is identified by using the pre-processed surface by contour processing. In this case, the positional relationship deriving unit 23 does not change the positions of the C-axis and the Z-axis as described in the ninth embodiment, but changes the XY position and uses the coordinate values of two or more points in contact with each other. The xy relative position between the axis rotation center and the cutting edge 11a can be identified.

Further, the shape error of the tool cutting edge can be measured by making multipoint contact on the curve where the same cutting edge position contacts in a posture in which the C-axis rotation position is 90 degrees different from that at the time of premachining. Further, as described in the seventh embodiment, by changing the Z position and making contact at two or more points in a posture in which the C-axis rotation position is 90 degrees different from that at the time of pre-machining, the C-axis rotation center and the Z-axis are parallel. Degree (tilt) can be identified.

<Example 13>
In Example 13, a method of identifying the mounting angle of the tool and the position of the center of rotation of the B-axis will be described using the machined surface to which the straight cutting edge is transferred.
FIG. 36 shows how the cutting edge 11a, which is a straight cutting edge, is being machined. Hereinafter, the inclination φ ^ of the main inclined surface of the fine groove of the machined surface determined by the mounting angle of the tool, L ^ which is the distance between the B-axis rotation center and the tip of the cutting edge, and β ^ which is the inclination with respect to the Z-axis are identified. The method will be explained. The slope φ ^ is the angle with the counterclockwise direction positive from the −X axis, and the slope β ^ is the angle from the −Z axis.
FIG. 37 is a diagram for explaining an identification method. The movement control unit 22 brings the cutting edge 11a into contact with the pre-machined surface at P1 at _{an arbitrary angle θ 1} , and detects _{z 1 which is the z position of P1.} Movement control unit 22, remains the same orientation, contacting the cutting edge 11a before processing surface and DX shifted by P2, to detect the _{z 2} and z position of P2.
As a result, if dz = z _2- z ₁
φ ^ = atan (dz / | DX |)
Is calculated. If this tilt angle deviates from the tilt angle of the target shape, the difference can be corrected on the B axis to perform fine groove machining with a more accurate tilted surface in the final finish.

FIG. 38 is a diagram for explaining coordinate transformation.
The relative relationship between the cutting edge tip point and the B-axis rotation center is expressed as follows.

となる。 When the coordinate system is transformed using φ so that the z coordinate at the cutting position is 0,

Will be.

FIGS. 39 (a) and 39 (b) show a state in which the posture of the cutting edge 11a is changed and brought into contact with the pre-processed surface.
FIG. 39A shows a state in which the cutting edge 11a is moved in a direction perpendicular to the inclination φ (parallel to the Z'axis) in a state where the _{B axis is rotated by θ 1 and brought into contact with the pre-machined surface.} FIG. 39B shows a state in which the cutting edge 11a is moved in a direction perpendicular to the inclination φ (parallel to the Z'axis) in a state where the _{B axis is rotated by θ 2 and brought into contact with the pre-machined surface.} For θ ₁ and θ ₂ , the counterclockwise angle is positive. At this time, as the z value, respectively z _'1 and z' ₂ and is detected.

なおｘ’_１＋、ｘ’_２＋は、適当なずらし量であり、ずらさなくてもよい。 Therefore, the following relationship is established.

Note that _x'1+ and _x'2+ are appropriate shift amounts and do not have to be shifted.

連立して解くと、

The z'coordinates at the above two contact points are obtained as follows.

When solved simultaneously,

Therefore,

と算出される。 Therefore,

Is calculated.

As described above, according to the thirteenth embodiment, the B-axis rotation center can be derived by bringing the cutting edge 11a into contact with a plurality of points on the machined surface to which the straight cutting edge is transferred. By knowing the exact center of rotation of the B-axis in this way, the B-axis is rotated to process because the angle of the inclined surface of the fine groove changes, for example, in a complicated shape in which the fine groove is formed on a free curved surface. When it is necessary to perform the above, the xy position of the tool cutting edge shifts and the machining accuracy deteriorates (if there is an error in the B-axis rotation center position relative to the tool cutting edge position, the tool cutting edge rotates due to the B-axis rotation. It is possible to prevent an error in the xy position).

In the following Examples 14 to 18, the process of specifying the deviation amount with respect to the cutting tool 11 which is a rotary tool will be described. In Examples 14 to 18, the movement control unit 22 uses the feed function of the feed mechanism 7 in the moving direction, which was not used during the cutting process, to feed the cutting tool 11 to the work material after the cutting process. The positional relationship deriving unit 23 specifies the amount of deviation with respect to the cutting tool 11 based on the coordinate values when the cutting tool 11 comes into contact with each other at at least two positions by moving them relative to each other. In each of the embodiments, the amount of deviation of the ball end mill having a hemispherical ball portion at the tip is obtained on behalf of the rotary tool, but the amount of deviation can be similarly specified for other types of rotary tools such as the radius end mill. ..

<Example 14>
In Example 14, a method for identifying the shape error of the cutting edge of the ball end mill will be described.
FIG. 40 shows two different postures A and B of the ball end mill in contact with the pre-processed surface of the work material 6. In the two postures A and B, the cutting edges at different angle positions when viewed from the center of the ball portion come into contact with the pre-machined surface. The posture A may be, for example, the posture at the time of forming the pre-processed surface. In Example 14, it is premised that the values other than the collapse of the cutting edge radius R are known.

In Figure 40, the distance L from the center of the ball portion to B axis center O _B, the angle theta, the angle in the posture B (θ + Δθ) in the position A, the ideal B axis center O _B of the transition from position A to position B movement amount ΔX _r is known. In this case, by measuring a moving amount of the B axis center _{O B,} when the amount of movement is (ΔX _r + Δx _er), collapse amount [Delta] R _er ^ is ball-shaped, obtained in the following manner.
Ball shape collapse amount ΔR _er ^ = Movement deviation amount Δx _er
From the above, the collapsed shape (shape error) of the cutting edge can be measured by bringing the ball end mill into contact with the pre-machined surface in two different postures.

<Example 15>
In the fifteenth embodiment, a method for specifying the spindle mounting error (tool runout amount ΔR ^) of the ball end mill will be described.
FIG. 41 is a diagram for explaining a method for specifying the amount of misalignment between the ball end mill and the spindle. In FIG. 41, the ball end mill shown by the solid line shows the contour shape when there is no misalignment, and the ball end mill shown by the dotted line shows the contour shape when there is misalignment. As shown in the figure, when the ball end mill is misaligned, cutting is performed on an outer circumference larger than the ideal value due to shaft deviation. In the fifteenth embodiment, it is assumed that values other than the tool runout amount ΔR ^ are known. The movement control unit 22 brings the ball end mill into contact with the pre-machined surface in two postures A and B.

により工具の振れ量ΔＲ＾が求められる。 _{The B-axis rotation phase θ 0} where the main axis and the Z axis are parallel, the angle θ in the posture A, and the angle (θ + Δθ) in the posture B are known, and the amount of runout that changes depending on the rotation Δθ between the posture A and the posture B is Δx. Is measured. At this time,

The amount of runout of the tool ΔR ^ can be obtained.

以上のように未知のＬ＾、θ＾を、３つの異なる姿勢で接触させることで導出できる。 <Example 16>
In Example 16, explaining a method of identifying an error in B-axis center O _B.
FIG. 42 is a diagram for explaining a method for specifying the amount of deviation of the center of the B axis. In Example 16, the distance from the center of the ball portion to B axis center O _B L ^, is the angle theta ^ unknown at any position, other values are known. The movement control unit 22 brings the ball end mill into contact with the pre-machined surface at an angle θ ^ of an arbitrary posture, and then changes the ball end mill back and forth twice at a known Δθ to bring the ball end mill into contact. In the 16th embodiment, the movement control unit 22 makes contact at an angle (θ ^ + Δθ) and an angle (θ ^ −Δθ), and the positional relationship deriving unit 23 measures _{the movement amounts Δx 1} and Δx _{2 in the X-axis direction at that time.} did. At this time, L ^ and θ ^ can be obtained by the following equations.

As described above, the unknown L ^ and θ ^ can be derived by contacting them in three different postures.

<Example 17>
_{In Example 17, an index θ xz} ^ regarding the degree of orthogonality between the X-axis and the Z-axis is specified. The index θ _xz ^ is the amount of deviation from a right angle between the X-axis and the Z-axis.
FIG. 43 is a diagram for explaining a method for specifying the amount of deviation from the right angle between the X-axis and the Z-axis. The distance L from the center of the ball portion to B axis center O _B, the angle of orientation A theta, the angle in the posture B (θ + Δθ), the ideal movement of B axis center O _B of the transition from position A to position B _(movement amount when the X-axis is perpendicular to the Z-axis) [Delta] X r, cutting edge radius R of the ball portion is known. When transitioning from the attitude A to position B, and the actual movement amount [Delta] x ₁ up to the cutting edge contacts the front working surface, index theta _{xz ^} relates orthogonality of the X and Z axes, found as follows ..

The 17th embodiment shows a method of deriving an index regarding the degree of orthogonality between the X-axis and the Z-axis. As described with respect to the 7th embodiment, the C-axis is formed by bringing the rotary tool into contact with the pre-machined work material 6. It is also possible to estimate the parallelism of the feed direction of the rotary tool with respect to.

<Example 18>
In Example 18, the error of the C-axis rotation center is first identified by using the pre-processed surface by scanning line processing. Also in the eighteenth embodiment, the cutting edge of the cutting tool 11 is brought into contact with the premachined surface at a plurality of points to derive the difference from the ideal profile, so that the relative C-axis rotation center position viewed from the tool center is obtained. Identify the error in.

FIG. 44 conceptually shows the cutting feed direction in the XZ plane and the pick feed direction in the YZ plane in scanning line machining. In order to identify the error of the center of rotation of the C axis, the shape of the workpiece in the YZ plane and the shape of the workpiece in the XZ plane can be used.

<Use of the shape of the workpiece in the YZ plane>
FIG. 45A shows the state of the cutting edge during processing. In FIG. 45A, the dotted line represents the cutting motion profile of the center of the ball portion during machining, and the solid line represents the pre-machined surface profile. The ideal ball center cutting motion profile and pre-machined surface profile are known.
FIG. 45B shows how the work is rotated 90 degrees around the C axis and then the cutting edge is brought into contact with the pre-machined surface at a plurality of points. In FIG. 45 (b), the solid line represents the contact surface profile connecting the contact points.

The positional relationship derivation unit 23 identifies the Y-direction error of the C-axis rotation center (X-direction error after C-axis rotation and before rotation) by numerical analysis so that the contact surface profile and the pre-machined surface profile fit best. .. Specifically, the positional relationship derivation unit 23 estimates each contact position from the pre-machined surface profile, derives an error from the actual contact detection position, and rotates the C-axis so that the sum of the errors is minimized. Identify the center coordinates.

<Use of the shape of the workpiece in the XZ plane>
FIG. 46A shows the state of the cutting edge during processing. In FIG. 46 (a), the dotted line represents the cutting motion profile of the center of the ball portion during machining, and the solid line represents the pre-machined surface profile. The ideal ball center cutting motion profile and pre-machined surface profile are known.
FIG. 46B shows how the work is rotated 90 degrees around the C axis and then the cutting edge is brought into contact with the pre-machined surface at a plurality of points. In FIG. 46 (b), the solid line represents the contact surface profile connecting the contact points.

The positional relationship derivation unit 23 identifies the X-direction error (the Y-direction error after C-axis rotation and before rotation) of the C-axis rotation center by numerical analysis so that the contact surface profile and the pre-machined surface profile fit best. .. Specifically, the positional relationship derivation unit 23 estimates each contact position from the pre-machined surface profile, derives an error from the actual contact detection position, and rotates the C-axis so that the sum of the errors is minimized. Identify the center coordinates.

As shown in FIG. 45 (b) or FIG. 46 (b), the relative C-axis rotation center position as seen from the center of the ball portion is identified. Once the C-axis rotation center position is identified, it can be used to measure the shape error of the cutting edge.
FIG. 47 shows a method for measuring the cutting edge shape error. The movement control unit 22 rotates the work 90 degrees around the C axis to bring the cutting edge into contact with the cutting edge on the pre-machined surface at a plurality of points along a curve so that the same cutting edge position comes into contact with each other. FIG. 47 shows a state in which the cutting edge contacts the pre-processed surface at the lowest point in the Z direction along the ridge indicated by the broken line. The positional relationship deriving unit 23 measures the collapse of the cutting edge shape from the calculated contact position at each contact point and the amount of deviation of the detected contact position in the same manner as in the sixth embodiment.

The present disclosure has been described above based on the examples. This embodiment is an example, and it will be understood by those skilled in the art that various modifications are possible for each of these components and combinations of each processing process, and that such modifications are also within the scope of the present disclosure. ..

The outline of the aspects of the present disclosure is as follows. A cutting device of one aspect of the present disclosure includes a rotating mechanism that rotates a spindle to which a cutting tool or a work material is attached, a feed mechanism that moves the cutting tool relative to the work material or a part, and a rotation mechanism. It is provided with a control unit that controls the rotation of the spindle and the relative movement of the cutting tool by the feed mechanism. The control unit uses the detection information of the contact sensor or the time-series data of the detection values of the drive motor included in the rotation mechanism and / or the feed mechanism to determine the coordinate values when the cutting tool comes into contact with the work material or part. It has a function to acquire. The control unit is at least 2 different from the rotation angle position of the cutting tool during turning with respect to the reference plane whose relative positional relationship with the work material after turning or the rotation center of the work material is known. At one position, the relative positional relationship between the cutting tool and the center of rotation of the work material is determined based on the coordinate values when the cutting tool comes into contact. According to this aspect, the control unit determines the relative positional relationship between the cutting tool and the rotation center of the work material based on the coordinate values of two or more contact positions, thereby measuring the positional relationship. There is no need to install a separate device.

Another aspect of the present disclosure is also a cutting device. This device has a rotating mechanism that rotates the spindle to which the cutting tool or work material is attached, a feed mechanism that moves the cutting tool relative to the object, and rotation of the spindle by the rotating mechanism and cutting by the feed mechanism. It is provided with a control unit that controls the relative movement of the tool. The control unit moves the cutting tool relative to an object with a known shape, and obtains the coordinate values when the cutting edge of the cutting tool comes into contact with the known shape of the object, such as the detection information of the contact sensor, or the rotation mechanism and / Alternatively, it has a function of acquiring using time-series data of detected values related to the drive motor included in the feed mechanism. The control unit has at least the nose radius of the tool cutting edge, the center coordinates of the tool cutting edge, and the shape error of the tool cutting edge based on the coordinate values when the cutting tool cutting edge contacts at least three positions of the known shape part of the object. Ask for one. According to this aspect, the control unit can obtain the value related to the tool cutting edge based on the coordinate values of three or more contact positions, and it is not necessary to separately mount a measuring instrument or the like.

Yet another aspect of the present disclosure is also a cutting device. This device uses a rotating mechanism that rotates the spindle to which the cutting tool or work material is attached, a feed mechanism that moves the cutting tool relative to the work material, and a spindle rotation and feed mechanism that uses the rotation mechanism. It is provided with a control unit that controls the relative movement of the cutting tool. The control unit acquires the coordinate value when the cutting tool comes into contact with the work material by using the detection information of the contact sensor or the time series data of the detection value of the drive motor included in the rotation mechanism and / or the feed mechanism. Has a function. The control unit moves the cutting tool relative to the work material after cutting by using the feed function of the feed mechanism in the movement direction that was not used during cutting, and there are at least two cutting tools. Based on the coordinate values at the time of contact at the position, at least one of the mounting error of the cutting tool, the shape error of the cutting edge of the tool, and the deviation of the cutting tool in the relative movement direction with respect to the work material is specified. The control unit uses the feed function of the feed mechanism in the moving direction, which was not used during cutting, so that the cutting tool mounting error, tool cutting edge shape error, and work can be performed without mounting a measuring instrument. At least one deviation in the relative movement direction of the cutting tool with respect to the material can be specified.

Yet another aspect of the present invention is also a cutting device. This device is included in a rotating mechanism that rotates a spindle to which a cutting tool or work material is attached, a feed mechanism that moves the cutting tool relative to the work material, and a rotation mechanism and / or a feed mechanism. It is provided with a control unit that specifies the contact position between the cutting tool and the work material from the time-series data of the detected values related to the drive motor. The control unit identifies the contact position based on the first time-series data of the detected value acquired before the contact and the second time-series data of the detected value acquired after the contact. According to this aspect, the control unit can accurately derive the contact timing between the cutting tool and the work material and determine the contact position by tracing back to the detected value before contact.

The control unit may acquire the second time series data including the detected value exceeding a predetermined threshold value. The control unit may set a predetermined threshold value based on the first time series data. The control unit may set a predetermined threshold value using the average value of the first time series data. The control unit may specify the contact position from the regression equation obtained by regression analysis of the second time series data and the average value of the first time series data.

1 ... Cutting device, 2a ... Spindle, 6 ... Work material, 7 ... Feed mechanism, 8 ... Rotation mechanism, 11 ... Cutting tool, 20 ... Control unit, 21 ... Rotation control unit, 22 ... Movement control unit, 23 ... Positional relationship derivation unit, 40 ... Reference block, 41 ... Mounting shaft, 42 ... Support device, 43 ... B Axis table.

Claims (2)

A rotating mechanism that rotates the spindle to which the cutting tool or work material is attached,
A feed mechanism that moves the cutting tool relative to the object,
The cutting tool includes a control unit that controls the rotation of the spindle by the rotation mechanism and the relative movement of the cutting tool by the feed mechanism, and the cutting tool has an arcuate cutting edge.
The control unit moves the cutting tool relative to an object having an arc surface having a known shape in a translational direction, and obtains coordinate values when the cutting edge of the arc of the cutting tool comes into contact with the arc surface of the object. It has a function of acquiring using the detection information of the contact sensor or the time-series data of the detection value of the drive motor included in the rotation mechanism and / or the feed mechanism.
The control unit has the nose radius of the tool cutting edge, the center coordinates of the tool cutting edge, and the coordinates of the nose radius of the tool cutting edge, based on the coordinate values when the arc cutting edge of the cutting tool and the arc surface of the object are in contact with each other at at least three different positions. Find at least one of the shape errors of the tool edge,
A cutting device characterized by that. A rotating mechanism that rotates the spindle to which the work material is attached,
A feed mechanism that moves the cutting tool relative to the work material,
A control unit that controls the rotation of the spindle by the rotation mechanism and the relative movement of the cutting tool by the feed mechanism is provided.
The control unit uses the detection information of the contact sensor or the time-series data of the detection value of the drive motor included in the rotation mechanism and / or the feed mechanism, and the cutting edge of the cutting tool comes into contact with the work material. It has a function to acquire the coordinate value of the time,
The control unit turns the work material after turning by moving the cutting tool relative to the work material by utilizing the feed function of the feed mechanism in one or more movement directions. The cutting tool is moved relative to the work material by utilizing the feed function of the feed mechanism in the movement direction that was not used during machining, and the cutting edge of the cutting tool comes into contact at at least two positions. At least one of the mounting error of the cutting tool, the shape error of the cutting edge of the tool, and the deviation of the cutting tool in the relative movement direction with respect to the work material is specified based on the coordinate values at the time of
A cutting device characterized by that.

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