JPH08267343A - Recognizing method of tool form - Google Patents

Abstract

PURPOSE: To measure the end-face position of a tool accurately by storing the extent of tool feed coordinates at a time when a tool end face was detected by the last measurement as the tool end-face position coordinates whenever the feed rate of a step is the same as that of a final step. CONSTITUTION: A grinding wheel is put back as far as one step portion in a direction separating from a laser measuring instrument (506), then step measurement is carried out again with the step value of one half of the initial step value. This stone end face detection (505) and one step retraction (506) and also restep measurement (507) at the step value of one half of the prestep value are repeated till the step value at the prestep measurement become equal to the final step value or smaller than it. In addition, when the prestep measurement's step value has become the same or smaller than it (508), a position of the stone end face detected by the adjacent measurement is stored in miry of a control part as a stone end face position coordinate Ze (509), and thus this measurement is over.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for recognizing the shape of a tool used in NC machine tool machining, and more particularly to a grinding wheel with a shaft used in a jig grinder or a cylindrical grinder, or a side surface shape used in a machining center or a milling machine. The present invention relates to a tool shape recognition method suitable for recognizing the shape of an end mill or the like.

[0002]

2. Description of the Related Art In a machine tool for automatic machining by NC (numerical control), in order to set an optimum tool working range and a tool diameter offset amount, information on a tool to be used is NC before starting machining. Must be entered in the device. For example, in a machine tool that performs cutting, the relative position between the tool end surface and the work table is found to set the tool operating range, and the tool diameter is found to set the tool diameter offset amount. Information on these tools also needs to be automatically measured based on commands from the NC device in order to achieve full automation of machining work.

From this point of view, various means have been developed for automatically measuring information such as the end surface of the tool, the diameter, the degree of wear and the like, and the method of detecting the tool in these has been to use a mechanical contact. , Those using electrical continuity, those using an acceleration sensor, and those using a CCD camera.

However, although the above-mentioned tool measuring method can be applied relatively easily to the measurement of cutting tools, drills, etc., it can also be applied to the axis grindstones used in NC jig grinders and cylindrical grinders. It was difficult.

The grindstone with a shaft is a tool in which abrasive grains are attached over a certain width from the end face of a cylindrical shank made of steel or cemented carbide, and the shank 11 from the grindstone end face e shown in FIG. A general type of grindstone 10 in which abrasive grains 12 are adhered to a part of the grindstone, and a grindstone end face e shown in FIG.
There is an extremely fine type grindstone 15 having low shank rigidity in which abrasive grains 17 are attached to the entire small diameter portion of the shank 16.

FIG. 2 shows a general example of a tool operating range in the case of machining using the grindstone with a shaft 10. In the figure, the processing range t is from the reference plane 2 of the work 1 to T
The machining start position Ts and the machining end position Te, which are separated by a distance of s ′ and Te ′, are designated, and the whetstone with a shaft 10 on the Z axis is specified.
While rotating and oscillating, draw a shape locus on the XY axis plane and perform machining. Here, the oscillation is performed by repeatedly moving the whetstone with a shaft 10 up and down within a certain range set by the top dead center coordinate Zu and the bottom dead center coordinate Zd, and does not synchronize with the movement of the work table 3. It is controlled by a single axis. In addition, the oscillation prevents the roughness of the grindstone from affecting the surface roughness and dimensional accuracy.

When performing this oscillation, it is necessary to set the position so that the straight portion c of the grindstone with a shaft 10 is brought into contact with the processing range t as much as possible. Also,
If the settings of the top dead center coordinate Zu and the bottom dead center coordinate Zd of the oscillation are inappropriate, the grinding resistance during machining changes due to the change in the contact area of the grindstone. Furthermore, when the amount of change in grinding resistance is large, the amount of bending of the grindstone also changes, which causes dimensional deterioration such as the taper of the machined surface and the shape of the tyco. This effect is inevitable in the case of a small-diameter grindstone with low rigidity. Therefore, in order to automatically set the tool operating range, in addition to the end surface position e of the grindstone with a shaft 10, a lower effective position a separated by a distance a ′ from the end surface e and an upper effective position b separated by a distance b ′ from the end surface e. If the outer diameter shape of the grindstone with a shaft such as the straight portion c from the lower effective position a to the upper effective position b cannot be measured, it cannot be realized.

However, the conventional tool measuring method described above cannot measure the lower effective position a, the upper effective position b, the straight portion c, and the like of the grindstone with a shaft 10. For this reason, the setting of the tool operating range in the grindstone with axis 10 is still performed by the operator actually applying the grindstone with the axis to the work, visually checking the positional relationship, reading the machine coordinate value at that time, and reading the NC program. And so on.

If the tool diameter offset amount is too large, air cutting (idling without processing) increases,
If it is too small, it will cut too much, resulting in damage to the grindstone and defective work. Therefore, it is necessary to offset the tool diameter also in the grindstone with a shaft. In this case, since the whetstone with a shaft has unevenness of abrasive grains, it is necessary to measure the tool diameter while rotating.

[0010]

As described above, in the grindstone with a shaft, it is possible to automatically measure the upper effective position, the lower effective position and the straight portion which are necessary for setting the tool operating range. Since this was not possible and the operator had to do it manually, there was the problem that it was not accurate and quick, and even with the ultrafine grinding stone, even manual measurement was extremely difficult.

In the measurement of the tool diameter for setting the offset amount, the number of rotations of the grindstone during machining is 100,000 to 200,000 r. p. Since it is a high speed rotation of m, it is necessary to measure at the actual machining speed in consideration of the influence of wobble of the grindstone, but when measuring the tool diameter at the actual machining speed by contact sensing, the measurement terminal Abrasion of the parts was unavoidable, lacked accuracy, and had a major problem in terms of maintenance of the measuring device. Furthermore, CC
In the case of using the D camera, there is a problem that the measuring device becomes expensive and large.

The present invention has been made to solve the above problems, and measures the end face position, the upper effective position and the lower effective position of a tool necessary for setting the tool operating range of a grindstone with a shaft, an end mill and the like. It is an object of the present invention to provide a tool shape recognition method capable of automatically and accurately performing the measurement and measuring the tool diameter required for setting the offset amount while rotating at the actual machining rotation speed.

[0013]

In order to achieve the above object, the invention according to claim 1 stepwise feeds a tool from a measurement start position toward a laser measuring instrument, and the laser measuring instrument detects an end face of the tool. When this is done, the tool is returned by at least one step, the feed amount for one step is made smaller than the feed amount for the previous one step, and the tool is step fed again in the direction of the laser measuring instrument, and the laser measuring instrument is used to step the end face of the tool. When is detected, the tool is returned by at least one step this time, and the above operation is repeated until the feed amount for one step becomes equal to or smaller than the feed amount for the final step that is set in advance. When the feed amount of is equal to or smaller than the feed amount of the final step, the tool feed coordinate when the tool end face is detected in the previous measurement is This is a method of storing the coordinates as the end surface position coordinates.

In the invention according to claim 2, scanning measurement is performed while the tool is step-fed from the measurement start position within the measurement area of the laser measuring instrument,
Obtain the average value of the tool outer diameter at this time, determine whether it is within the range of the tool outer diameter average value obtained from the measurement data up to the previous time, and if it is within the range, perform the next scanning measurement. , This operation is repeated, and when the average value is out of the range of the average value obtained by the measurement data up to the previous time, the tool is returned by one step or more, and the feed amount for one step is fed by the previous one step. Scanning measurement of the tool in the laser measuring device again with a smaller amount than the amount, and the operation of ,, and is repeated until the feed amount of one step is equal to or smaller than the feed amount of the final step set in advance, When the feed amount for one step is the same as or smaller than the feed amount for the final step, the tool feed coordinates when the tool outer diameter average value detected in the previous measurement is out of range This is a method of storing the effective position coordinates.

In the invention according to claim 3, the tool is moved from the effective position coordinate of the grindstone to the measurement start position in the measurement area of the laser measuring device, and then the tool is stepwise fed in the downward effective position direction. , Scanning measurement is performed to obtain the average value of the tool outer diameter at this time, and it is determined whether it is within the range of the tool outer diameter average value obtained from the measurement data up to the previous time. Scanning measurement is repeated and this operation is repeated. When the average value is out of the range of the average value obtained from the measurement data up to the previous time, the tool is returned by one step or more and the feed amount for one step is increased. Is set to be smaller than the previous one-step feed amount, and the tool is again scanned and measured in the laser measuring instrument. Repeat until the feed amount of the final step is equal to or smaller than the feed amount of the last step, and when the feed amount of 1 step is equal to or smaller than the feed amount of the final step, the tool outer diameter average value detected in the previous measurement is out of range This is a method of storing the tool feed coordinate when it becomes as the tool lower effective position coordinate.

Further, in the invention according to claim 4, the tool is oscillated between the upper effective position and the lower effective position of the tool which are obtained in advance, and the average of the outer diameter of the tool is calculated from the data measured by this oscillation. This is a method of obtaining a value and storing 1/2 of the average value as a tool radius offset amount.

The invention according to claim 5 continuously detects the tool end surface position coordinates of claim 1, the tool upper effective position coordinates of claim 2, and the tool lower effective position coordinates of claim 3. I am doing it.

According to a sixth aspect of the present invention, the tool end surface position coordinates of the first aspect are detected, the tool upper effective position coordinate of the second aspect is detected, the tool lower effective position coordinate of the third aspect, and the claim. The offset amount of tool diameter 4 is continuously detected.

Further, the invention according to claim 7 uses the tool as a grindstone with a shaft, the invention according to claim 8 rotates the tool, and the invention according to claim 9 uses the tool. The feed amount of one step after returning by at least one step is set to 1/2 of the feed amount of the previous one step.

[0020]

The method of the present invention will be described below. FIG. 3 shows an example of an apparatus used when carrying out the method of this embodiment. As shown in the figure, the work 1 is placed on the work table 3 via a jig 4. Laser measuring device 2
Reference numeral 0 indicates a light emitting portion 21 and a light receiving portion 22, and the positional relationship with the work is clear on the work table 3 or a table having the same height as the work table 3, and the work is positioned within the working range of the tool. It has been placed. Further, although not shown, a control unit is provided which performs various processes based on a signal from the laser measuring device 20 and outputs necessary data to the machine tool body.

Here, the laser measuring device 20 scans the laser light 23 from the light emitting portion 21 at high speed, and detects the end surface and the outer diameter of the tool 10 inserted so as to block the laser light 23. In addition, the control unit statistically processes the outer diameter data of the tool 10 measured at the sample rate specified in advance by the laser measuring device 20, and obtains data such as the maximum, minimum, average, range, standard deviation of the tool diameter, and the number of samples. Ask. The main body of the machine tool (not shown) moves the tool 10 relative to the work 1 (work table 3) in the X-, Y-, and Z-axis directions based on the operation signal from the control unit.

Next, a method of recognizing a tool shape using the above apparatus will be described. First, the positional relationship among the grindstone with a shaft 10, the laser measuring device 20, and the work 1 is determined as shown in FIG. That is, the machining information of the work in the work drawing is as follows. -Ts: Machining start position-Ts': Distance from workpiece reference plane to machining start position Ts-Te: Machining end position-Te ': Distance from workpiece reference plane to machining end position Te-t: Machining range (Ts' -Te ') Further, the height Hw from the work table 3 to the work reference surface 2 is measured in advance. The Z-axis coordinate and tool diameter data are treated as a pair of information, and the outer shape of the tool (unevenness)
And the relative position between the tool and the work table. Each Z-axis coordinate obtained by the laser measuring device 20 is as follows. Ze: end face coordinates (coordinates away from reference position 6 Ze ') Za: lower effective position coordinates (coordinates away from reference position 6 Za') Zb: upper effective position coordinates (away from reference position 6 Zb ' Coordinates) Here, the reference position 6 is the position of the whetstone end surface at the time of the Z-axis origin. Further, the height Hl of the laser beam 23 from the work table 3 or the like is measured in advance.

In the case of machining the through hole shown in FIG. 3, Zu: top dead center coordinate (-Zb'-Hl + Hw-Ts ') Zd: bottom dead center coordinate (-Za'-Hl + Hw-Te') )

In the case of performing bottoming processing shown in FIG. 3, Zu: top dead center coordinate (-Zb'-Hl + Hw-Ts ') Zd: bottom dead center coordinate (-Ze'-Hl + Hw-Te') (However, with respect to the Z-axis coordinate, the work table direction is the − direction with reference to the reference position 6). Also, O
s: The amount of oscillation (Zd to Zu) is also obtained. However, in the method of setting the top dead center coordinate Zu and the bottom dead center coordinate Zd, the machining start position Ts and the lower effective position a and the machining end position Te and the upper effective position b (e grinding wheel end face in bottom machining) match. This is a standard pattern, and in practice, the grindstone type can be divided into several patterns in relation to the work shape.

[Detection of Grindstone End Face Position Coordinates] First, a method of detecting the grindstone end face position coordinates Ze will be described. Whetstone 10
While moving in the Z-axis direction, the end face of the grindstone is gradually moved closer to the laser beam. Then, the grindstone 10 blocks the laser beam 23, and the Z-axis position when the number of samples changes from 0 to some numerical value is obtained, and this position is the coordinate position Z of the end face of the grindstone.
detected as e.

Z is applied in the direction in which the grindstone blocks the laser beam (-direction).
In the step of axial movement, the steps of fast-forwarding step movement and step measurement are repeated until the end face is detected with the same step amount. In addition, as the step amount, an initial step amount (for example, 1.000 mm) in which one step is large and a final step amount (for example, 0.001 mm) in which one step is minute are set in advance.

The laser measuring device 20 is capable of continuous measurement, sets a sample rate (sampling time interval), and measures for a fixed time. Further, the control unit (not shown) has a function of outputting statistical values such as maximum, minimum, average, range, standard deviation and the number of samples based on the measurement data from the laser measuring instrument.

That is, as shown in FIG. 5, the grindstone 10 is rotated (501) and fast-moved to the measurement start position (502). From the measurement start position, the grindstone is moved in the direction (-Z) of the laser measuring device 20 with the initial step amount (503).
Direction), and step measurement is performed (504). When the grindstone end face e blocks the laser beam 23 by repeating the step measurement (505), the grindstone 10 is returned in the direction (+ Z direction) away from the laser measuring instrument 20 for one step (50).
6) Next, step measurement is performed again with a step amount that is ½ of the initial step amount. This grindstone end face detection (50
5) and 1 step backward (506) and 1 of the previous step amount
The re-step measurement (507) with the step amount of / 2 is repeated until the step amount of the re-step measurement is equal to or smaller than the final step amount. Then, when the step amount of the re-step measurement becomes equal to or smaller than the final step amount (508), the position of the grindstone end face e detected by the measurement immediately before that is set as the grindstone end face position coordinate Ze and the memo of the control unit. It is stored in the memory (509) and the measurement is completed.

Before starting the measurement, the initial step amount and the final step amount are set. Further, if the measurement time becomes long if the step measurement is performed from the reference position 6, the position where the grindstone does not reach the laser beam is set as the measurement start position (501), and the grindstone is set to be fast-forwarded from the reference position 6. I'll do it.

[Detection of the upper effective position coordinates of the grindstone] Next, a method of detecting the upper effective position coordinates Zb of the grindstone 10 will be described with reference to FIG. The grindstone 10 is fast-forwarded to the grindstone end surface position coordinates Ze obtained by the above-mentioned detection method or another detection method (601), and further, is fast-moved to the measurement start position while the laser light is blocked (602). From the measurement start position, the grindstone is fed in the -Z direction with the initial step amount (603) and step measurement is performed (604). Here, the measurement start position is set in advance as a position at a predetermined distance from the end face of the grindstone 10.

In this case, the measurement is performed while the grindstone is moved stepwise at a constant speed by a constant amount. That is, the control unit periodically inputs the detection data from the laser measuring device 20 to perform the scanning measurement, takes in the average value μ and the standard deviation σ of the statistical data (605), and the average value μ of the tool outer diameter is the past data. Detects a step that changes suddenly with respect to. Specifically, the detection judgment reference data MIN = (μ1 + μ2 + ... + μn-1) / n-1-constant α × (σ1 + σ2 + ・ ・ ・ σn-1) / n-1 MAX = (μ1 + μ2 + ・ ・ ・ + μn-1) / n-1 + constant α × (σ1 + σ2 + ・ ・ ・ σn-1) / n-1 Is compared to determine whether the current average value μn of the tool outer diameter is within the range of the detection determination reference data (606). If it is within the range, the current average value μ and the standard deviation σ are detected and determined. In addition to the reference data, the next scanning measurement is performed, and when it is out of the range, it is determined that the upper effective position is included in the step, and the grindstone 10 is returned by 1.5 steps in the + Z direction (607). Then, the step amount is halved, and the scanning measurement is performed again (60
8). If it is out of the range, the average value μn and standard deviation σn of the current measurement are not added to the detection determination reference data. This process is repeated, and when the step amount reaches the final step amount, the measurement is ended (609).

When the step amount becomes equal to or smaller than the final step amount, the tool feed position detected by the immediately preceding measurement is stored in the memory in the control unit as the grinding wheel upper effective position coordinate Zb (610). ). That is, n
The upper effective position b is detected based on whether or not the average value μ of the second time is within the range of variation in the past average value. However, in the first measurement, only the process of obtaining the detection determination reference data is performed, and the upper effective position is determined after the second measurement.

The step return amount is set to 1.5 steps instead of 1 step in order to avoid an oversight when the upper effective position b is near the beginning or end of the step. Before starting the measurement, the initial step amount and the final step amount are set. Further, the standard deviation constant α is a constant that determines the position detection force, and sets a range of allowable variations in the past average value with respect to the average value μ. As a result, the reference position 6
The effective position coordinate Zb above the grindstone is obtained.

[Detection of lower effective position coordinates of grindstone] Next,
A method of detecting the lower effective position coordinates Za of the grindstone 10 will be described with reference to FIG. 7. The grindstone 10 is fast-forwarded to the grindstone upper effective position coordinate Zb obtained by the detection method (701), and the grindstone upper effective position coordinate Zb is set as a measurement start position from which the grindstone 10 is moved in the + Z direction at the initial step amount (702). And step measurement (703) is performed. Subsequent steps are
The only difference is that the grindstone 10 is step-fed in the + Z direction and returned in the -Z direction, except that the grindstone lower effective position coordinates Za are obtained and stored in the same procedure as the above-mentioned upper effective position coordinate detection method of the grindstone (704-). 709). As a result, the grinding wheel lower effective position coordinate Za from the reference position 6 is obtained.

[Measurement of Grinding Wheel Diameter] FIG.
It will be explained by. Prior to oscillating the grindstone 10, the top dead center coordinate Zu and the lower effective position coordinate Za of the grindstone,
Also, the oscillation range of the grindstone 10 is set so that the bottom dead center coordinate Zd and the upper effective position coordinate Zb respectively match (801, 802). Then, while rotating the grindstone 10 (803), oscillation is started (80).
4). Then, the average value μ of the tool outer diameter is fetched by the statistical data fetching command (805), and the average value μ is ½.
Is calculated as the tool diameter offset amount d and stored (80
6) Then, the oscillation ends (807).

In this embodiment, the above-mentioned grindstone end surface coordinates Ze, the above-mentioned grindstone upper effective position coordinates Zb, the above-mentioned grindstone lower effective position coordinates Za, and the tool diameter offset amount d are continuously measured.

These grindstone end surface coordinates Ze, grindstone lower effective position coordinates Za, grindstone upper effective position coordinates Zb, tool diameter offset amount d, height Hw from the work table to the work reference surface, and machining start position Ts. , Machining end position T
The working range of the tool can be automatically set based on e and the height Hl from the work table to the laser beam.
Further, by measuring the tool diameter offset amount d of the grindstone with a shaft that rotates at the same number of revolutions as the actual machining, it becomes possible to automatically set the optimum offset amount.

The present invention is not limited to the above embodiment, but can be applied to the recognition of the tool shape of an end mill or the like. In this case, the detection judgment data is
The maximum value of the tool outer diameter may be used, and the average of the maximum values and the standard deviation of the maximum values may be used as the detection determination criteria. Further, the returning amount of the tool and the step amount at the time of re-feeding described above can be the returning amount and the step amount other than those in the above-described embodiment. Furthermore, the detection determination reference value can be set not only from the average value μ and standard deviation σ of the statistical data relating to the tool outer diameter described above, but also from the maximum value and the minimum value relating to the tool outer diameter.

[0039]

As described above, according to the method for recognizing the tool shape of the present invention, each position in the tool shape required for setting the working range of the tool can be accurately and automatically measured. Therefore, it is possible to automate the setting of the working range of the tool. Further, by measuring the tool diameter offset amount d of the grindstone with a shaft that rotates at the same number of revolutions as the actual machining, it is possible to automate the optimum offset amount setting.

[Brief description of drawings]

1A and 1B are views showing a general shape of a grindstone with a shaft.

FIG. 2 is a diagram showing a tool operating range during processing of a grindstone with a shaft.

FIG. 3 is a diagram showing a positional relationship among a grindstone with a shaft, a laser measuring device, and a work.

FIG. 4 is a diagram showing a state in which a tool is positioned in a laser beam of a laser measuring instrument.

FIG. 5 is a flow chart for explaining a detection procedure of a grindstone end face position coordinate.

FIG. 6 is a flowchart illustrating a procedure for detecting upper effective position coordinates.

FIG. 7 is a flowchart for explaining a procedure for detecting lower effective position coordinates.

FIG. 8 is a flowchart for explaining a measuring procedure of a tool radius offset amount.

[Explanation of symbols]

 1: Work 2: Work reference plane 3: Work table 10, 15: Tool 20: Laser measuring instrument

Claims (9)

[Claims] 1. A step feed of a tool from a measurement start position toward a laser measuring instrument, and when the laser measuring instrument detects a tool end face, the tool is returned by at least one step, and the feed amount of one step is set to the previous time. And feed the tool stepwise toward the laser measuring instrument again, and when the end face of the tool is detected by the laser measuring instrument, the tool is returned by at least one step this time, Is repeated until the feed amount for one step is equal to or smaller than the preset feed amount for the final step, and when the feed amount for one step becomes equal to or smaller than the feed amount for the final step, A method for recognizing a tool shape, characterized in that the tool feed coordinates at the time of detecting the tool end face in the measurement are stored as the end face position coordinates of the tool. 2. The tool is step-fed from the measurement start position within the measurement area of the laser measuring device, and scanning measurement is performed to obtain an average value of the tool outer diameter at this time, which is obtained from the measurement data up to the previous time. It is determined whether or not it is within the range of the tool outer diameter average value, and if it is within the range, the next scanning measurement is performed, and this operation is repeated, and the average value is the average value obtained from the measurement data up to the previous time. When it is out of the range, the tool is returned by one step or more, the feed amount for one step is made smaller than the feed amount for the previous one step, and the tool is scanned and measured again in the laser measuring instrument. , Is repeated until the feed amount of one step is equal to or smaller than the preset feed amount of the final step. The tool feed coordinates when the average tool outer diameter detected in the previous measurement is out of range when it is the same as or less than the tool feed amount are stored as tool upper effective position coordinates. Recognition method. 3. The tool is moved from the coordinate of the upper effective position of the grindstone to the measurement start position within the measurement area of the laser measuring instrument, and then the tool is stepwise fed in the direction of the lower effective position to perform scanning measurement. The average value of the tool outer diameter of is determined, and it is determined whether or not it is within the range of the tool outer diameter average value obtained from the measurement data up to the previous time, and if it is within the range, the next scanning measurement is performed and this The operation is repeated, and when the average value is out of the range of the average value obtained by the measurement data up to the previous time, the tool is returned by one step or more, and the feed amount for one step is Scanning measurement of the tool is made again in the laser measuring device after making it smaller, and the operation of ,,, is the feed amount for one step, and the feed amount for the final step that is set in advance. Repeat until the feed amount for one step is the same as or smaller than the feed amount for the final step. When the feed amount for one step is equal to or smaller than the feed amount for the last step, the tool feed coordinates when the average tool outer diameter detected in the previous measurement is out of range A method for recognizing a tool shape, characterized by storing it as effective tool lower position coordinates. 4. A tool is oscillated between an upper effective position and a lower effective position of the tool which have been obtained in advance, and an average value of the tool outer diameter is obtained from the data measured by this oscillation, and the average. A method for recognizing a tool shape, characterized by storing 1/2 of the value as a tool radius offset amount. 5. A tool, characterized in that the detection of the tool end surface position coordinates of claim 1, the detection of the tool upper effective position coordinates of claim 2, and the detection of the tool lower effective position coordinates of claim 3 are performed continuously. Shape recognition method. 6. A tool end surface position coordinate according to claim 1, a tool upper effective position coordinate according to claim 2, a tool lower effective position coordinate according to claim 3, and a tool radius offset amount according to claim 4. A method for recognizing a tool shape, which is characterized by performing detection continuously. 7. The tool according to claim 1, wherein the tool is a grindstone with a shaft.
Alternatively, the tool shape recognition method according to item 6. 8. The method for recognizing a tool shape according to claim 1, wherein the method is performed while rotating the tool. 9. The tool according to claim 1, wherein the feed amount of one step after returning the tool by one step or more is 1/2 of the previous feed amount. Shape recognition method.