JPH09239631A - Numerically controlled machine tool with tool forming function - Google Patents

Abstract

PROBLEM TO BE SOLVED: To permit the continuous operation for a long time, and improve the machining accuracy largely. SOLUTION: In this numerically controlled machine tool, a cutting tool 4 is changed by utilizing an automatic tool change device 5 and the like, and a work is being machined. A tool forming means 9 to form the cutting tool 4 installed to the main spindle 3 of this numerically controlled machine tool in the installing condition is provided. In such a forming, the forming means 9 is provided in the position of the work in the nonmachining time of the work, so as to form the cutting tool 4, or the cutting tool 4 is formed in the waiting time to machine the work when the work is machined, for example.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a numerically controlled machine tool for machining a workpiece with a cutting tool attached to a spindle, and in particular, an improvement of a numerically controlled machine tool suitable for use as a machining center having an automatic tool changing device. Regarding

[0002]

2. Description of the Related Art In recent years, in the process of using expensive equipment such as a machining center, the wage has risen,
There are 24 hours of unmanned driving. In such a numerically controlled machine tool, when the wear of the cutting tool progresses, the operation is stopped and the cutting tool is removed from the machine tool. Then, the removed cutting tool is shaped by the grinder of the tool grinding chamber, and then attached to the machine tool again.

Further, in a numerically controlled machine tool having a tool life management function, a plurality of types of cutting tools of the same shape are prepared in advance in a tool magazine of the machine tool and are in use. When the cutting tool reaches the set number of times of machining, the machining operation is interrupted, the interrupted position is memorized, and a previously stored tool exchange program is called to execute and exchange with another cutting tool of the same type. are doing.

[0004]

However, in a conventional numerically controlled machine tool such as a machining center, even when an unattended operation is performed for 24 hours, if all the necessary cutting tools are worn out, machining is performed there. It has been interrupted, and it is a situation in which it is impossible to operate unmanned for 24 hours. Even if the cutting tool is accurately formed by a dedicated tool grinder, etc., if it is attached to the spindle of a machine tool such as a machining center, the cutting tool will have 10
A core runout of 30 μm occurs, and it is a situation in which it is impossible to process parts such as optical parts that require micron-order accuracy.

As described above, the core runout of the newly installed cutting tool is the sum of the runout due to the rotation of the spindle, the chuck mounting error, the cutting tool manufacturing error, etc., and the machining accuracy deteriorates if the machining is performed as it is. . In other words, when a cutting tool is attached to a spindle such as a machining center and rotational motion is applied, the movement trajectory of each cutting edge becomes uneven due to the rotational runout of the spindle and chuck mounting error, etc., resulting in uniform and stable machining. I can't do it. The state of such deterioration of the machining accuracy will be described when the end mill as a cutting tool is attached to the spindle of the machining center. Rotational runout ε1 exists on the main shaft of the machining center. On the other hand, since the sleeve of the spindle is different from the sleeve of the tool presetter, a mounting error ε2 occurs. Then, when the end mill whose radius is measured by the tool presetter is R is attached to the main shaft and rotated, the turning radius drawn by the cutting edge becomes R + ε1 + ε2, which causes an error.
This ε1 + ε2 is called an enlargement margin and becomes a factor that deteriorates the processing accuracy. Further, the amount of cutting per blade becomes non-uniform, and if the value of ε1 + ε2 is large, not only cutting blades that do not cut at all appear, but also the surface roughness of the workpiece is reduced.

An object of the present invention is to provide a numerically controlled machine tool which enables continuous operation for a long time. Also,
It is an object of the present invention to provide a numerically controlled machine tool, especially a machining center, which can greatly improve machining accuracy.

[0007]

In order to achieve such an object, in the invention according to claim 1, in a numerically controlled machine tool having an automatic tool changer, a cutting tool attached to a spindle is molded in the attached state. A tool forming means is provided.

According to the second aspect of the present invention, in a numerically controlled machine tool for exchanging a cutting tool attached to a spindle to machine a workpiece, a tool forming means for forming the cutting tool attached to the spindle is provided. When the work piece is not processed, the cutting tool is formed by bringing the forming means to the position of the work piece.

Further, in the invention according to claim 3, in the numerically controlled machine tool according to claim 1 or 2, the cutting tool is formed during a waiting time for machining the workpiece with the cutting tool. are doing.

Further, in the invention according to claim 4, in a numerically controlled machine tool having an automatic tool changer, a cutting tool detached from a spindle is molded by a tool forming means provided in the machine tool.

A numerical control machine tool such as a machining center of the present invention forms a cutting tool attached to a spindle,
Immediately after the completion of molding, the workpiece is processed. That is, prior to processing a work piece, a cutting tool attached to a spindle is formed, or a cutting tool attached to a spindle is formed by using a waiting time between machining. Then, after the completion of the forming, the formed cutting tool is not removed from the spindle, and the processing operation of the workpiece is started in the mounted state.

Further, in the numerically controlled machine tool of the present invention, the cutting tool removed from the spindle is molded by the tool molding means in the machine tool. Then, in parallel with the forming operation, the workpiece is processed by the cutting tool newly attached to the spindle.

Therefore, this numerically controlled machine tool can be operated continuously for a long time. Moreover, when the cutting tool is formed while being attached to the spindle, the runout of the cutting tool is eliminated and the machining accuracy is improved. Further, by frequently forming the cutting tool, it is possible to prevent deterioration of processing accuracy due to wear of the cutting tool.

[0014]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of a numerically controlled machine tool according to the present invention will be described below with reference to FIGS.

This numerically controlled machine tool utilizes a conventional machining center, and as shown in FIG.
A spindle head 2 placed on the main body 1, a spindle 3 held by the spindle head 2, a cutting tool 4 attached to a chuck of the spindle 3, and a plurality of cutting tools 4 are provided for automatic tool exchange. Automatic tool changer unit 5, a work table 6 for holding a work to be a workpiece, an on-machine measurement unit 7 for measuring the wear state and shape of the cutting tool 4, and the cutting tool 4 are ground. On-machine grinding unit 9 having a grindstone 8 that serves as a grinding tool, and a guide table 10 on which the work table 6 and the on-machine grinding unit 9 are placed and which guides them to the position of the spindle 3.
And a control unit (not shown) that controls the relative position of the work and the cutting tool 4 and the like. It should be noted that this machine is an apparatus for processing optical parts and the like that require precision on the order of microns. The control unit also controls the spindle head 2, the automatic tool change placement unit 5, the on-machine measurement unit 7, and the on-machine grinding unit 9. Further, the on-machine grinding unit 9 constitutes a tool forming means.

In the numerically controlled machine tool of this embodiment, the X, Y, Z axes of the machining center and the spindle rotation (B
Position and posture control of a total of 5 axes is performed by interlocking the 4 axes of the on-machine grinding unit 9 with the 1 axis of the grindstone of the on-machine grinding unit 9 (A axis). Then, the main body 1, the spindle head 2, the spindle 3, the cutting tool 4, the automatic tool conversion device 5 and the work table 6
Has the same structure as a conventional machining center, and detailed description thereof will be omitted.

The on-machine measuring unit 7 can measure the three-dimensional shape of the cutting tool 4 in cooperation with the spindle rotation angle (hereinafter referred to as B angle) of the machining center and the X, Y and Z axis feeds. . As shown in FIG. 2, the on-machine measurement unit 7 includes a displacement meter 12 having a tool measurement probe 11 for measuring the cutting tool 4, and a measurement holding unit that supports the displacement meter 12 and contacts the work table 6. And a section 13.
The displacement meter 12 is of a contact type using a differential transformer and a lever. Also, as shown in FIG.
The tool measuring probe 11 contacts the cutting tool 4 at an angle of 45 degrees with respect to the vertical direction.
It is possible to displace in the direction of the arrow. The on-machine measurement unit 7 using the displacement gauge 12 rotates the cutting tool 4 that is in contact with the tool measurement probe 11 and rotates the cutting tool 4 that is built in the spindle 3.
The profile of the cutting tool 4 is measured by using the output of the encoder having a resolution of 1 degree and the output of the displacement gauge 12 measured by the tool measurement probe 11. The displacement meter 12 has a resolution of 1 μm,
It has a side length of 1 mm.

The tool measuring probe 11 serving as a probe of the on-machine measuring unit 7 is strong against coolant. The displacement meter 12 is an analog type and uses a differential transformer. Other than the analog type, a capacitance type sensor, an eddy current sensor or the like may be adopted. If it is a digital type, a magnetic scale or the like may be adopted. It is difficult for the on-machine measurement unit 7 to have a structure that enables measurement even when approaching from any direction, but it is possible to cope with it by combining parallel springs, for example.

A specific example of a method of measuring the cutting tool 4 using the on-machine measuring unit 7 will be described by taking an end mill having four twisting blades shown in FIGS. 3 and 4 as an example. This measurement is performed using the function of controlling the three orthogonal X, Y, and Z axes of the numerically controlled machine tool and the B angle, which is the rotation angle of the main spindle. First, the radius from the rotation center of the end mill which is the cutting tool 4 is measured for each cutting edge. This measurement starts with the tool measuring probe 11 being brought rapidly close to the end mill and stopped at a position slightly inward of the radius based on the diameter and length of the end mill stored in the control unit. That is, the tip of the tool measurement probe 11 is aligned with the direction of the center P of the end mill serving as the cutting tool 4, and the tool measurement probe 11 is brought into contact with the cutting tool 4. The tool measurement probe 11 shown by the solid line in FIG. 3 shows the state immediately before the stop. This approach is performed by operating the X, Y, and Z axes.

Then, as shown in FIG. 4, the main shaft 4 is rotated in the arrow C direction. Then, when the cutting edge of the end mill is projected, the tool measurement probe 21 moves in the arrow D direction, and when the cutting edge is retracted due to wear or the like, it moves in the arrow E direction. This movement measures the height and position of the four twist blades.
That is, it is measured by adding the plus and minus values of this operation to the value of the initial position. In this way, the profile of each cutting edge is measured while controlling the B angle. Then, the entire shape of the cutting tool 4 can be measured by moving the tool measurement probe 11 in the Z-axis direction, that is, in the F direction shown by the arrow in FIG. 3, and repeating the movement. The tool measurement probe 11 shown by the dotted line in FIG. 3 shows a state where the bottom blade of the cutting tool 4 is being measured.

On the other hand, the on-machine grinding unit 9 has a grindstone 8 for grinding the cutting tool 4, as shown in FIGS.
In addition to the grinding motor 14 for rotating the grindstone 8,
A grinding spindle 15 that holds the grinding motor 14 and rotates it in a vertical plane, and a grinding stone 8 that rotates the grinding spindle 15.
The tilting motor 16 for adjusting the angle A, which is the tilting angle, the encoder 17 for detecting the tilting angle of the grindstone 8, and the grinding holding portion 18 that holds the tilting motor 16 and the like and is supported by the work table 6. Have. The grindstone 8 is inclined so that the cutting tools 4 having different lead angles can be dealt with.

Here, the grindstone 8 has a diameter of 100 mm and a rotation speed of 6,000 γpm. Further, the rotational runout of the grindstone 8 is within 0.5 μm, and the grinding spindle 15
The inclination range, that is, the value of the A angle is ± 30 degrees, and the inclination accuracy is within ± 0.05 degrees. The shape and type of the grindstone 8 is a cup type and a metal bond CB.
N whetstones are preferred.

On-machine grinding unit 9 having the above structure
The grinding method will be described. Grinding of the cutting tool 4 is performed by X, Y, Z which the numerically controlled machine tool has, as in the previous measurement.
The three orthogonal axes and the B-angle control function are used. As an example, a case of an end mill having a twisted blade will be described. There are two cutting edges of the end mill, the outer peripheral portion and the bottom portion. When the cutting edge of the outer peripheral portion is formed, that is, re-ground, three methods are conceivable: a method of removing the rake face, a method of removing the flank, and a method of removing both sides. On the other hand, if the rotation axis of the grindstone 8 is orthogonal to the rotation axis of the end mill, the chuck grasping the end mill and the grindstone 8 interfere with each other, and therefore only the parallel method can be adopted. In that case, it is difficult to grind the rake face, and it is limited to the method of removing the flank face. When the outer peripheral portion of the grindstone 8 is brought into contact with the flank of the cutting edge, the flank has an arc shape, but does not affect the performance of the cutting tool 4. Therefore, in this embodiment, a method of removing the flank is adopted.

Specifically, as shown in FIG. 7, in the extension direction of the cross line connecting the tip of each cutting edge of the end mill and the center P,
The center q of the grindstone 8 is arranged so as not to come, that is, the center q of the grindstone 8 is shifted in a direction parallel to the other straight line of the crosshair. Then, the A angle is controlled, the grindstone 8 is tilted, and the circumferential portion 8a of the grindstone 8 is brought into contact with the cutting edge at a right angle.

The relative movement of the cutting tool 4 and the grindstone 8 is as follows. That is, with the end mill serving as the cutting tool 4 stationary, the grindstone 8 rotating in the direction of the arrow H is positioned below the lower end of the cutting tool 4 and moved closer to a predetermined position within the X and Y coordinates to make a cut. give. After that, slowly rotate the end mill in the direction of arrow G in FIG.
It is moved downward while controlling the angle, and is always abutted so that the circumferential portion 8a of the grindstone 8 completely faces the tip surface of the cutting edge. In this way, when one cutting edge is finished, the grindstone 8 is returned to the original position and the next cutting edge is finished. In this way, all the cutting edges are successively reground. In such a case,
If the relative position of the grindstone 8 and the cutting tool 4 differs for each cutting edge,
Since the cutting edges of the cutting tool 4 are uneven, the relative positions of the cutting tool 4 and the grindstone 8 must be accurately controlled.

The bottom blade of the cutting tool 4 is formed as follows. That is, the end surface 8b of the grindstone 8 is used as shown in FIG. Then, the grindstone 8 is tilted by the clearance angle of the cutting edge, and the end surface 8b of the grindstone 8 is ground. As described above, the peripheral surface and the bottom portion of the cutting tool 4 are ground.

Next, the operation of the numerically controlled machine tool configured as described above will be described based on the operation sequence of FIG.

First, a tool setting step S1 is performed. In this step S1, the purchased cutting tool 4 or the hand-held cutting tool 4 is set in the automatic tool changer unit 5. Then, at that time, the tool shape data such as the tool number, the tool length, and the tool diameter are input to the control unit. The data of the tool length and the tool diameter at this time may be roughly accurate, that is, a nominal value.
This is to use the tool measurement probe 11 as data for rapidly approaching the cutting tool 4 during measurement as described above.

Next, a tool shape measuring step S2 is performed.
In this step S2, the cutting tool 4 in the automatic tool changer unit 5 is called and attached to the spindle 3. Then, with the cutting tool 4 attached to the spindle 3, the tool length, tool diameter,
The cutting edge position, lead angle, and cutting edge height are measured and input to the control unit and stored.

Thereafter, the tool forming step S3 is executed. In this step S3, the grinding amount and the control amount are determined from the shape measurement data, and the A axis of the on-machine grinding unit 9 and the XYZ and B axes of the machining center are controlled to form the cutting tool 4. This molding removes the runout of the cutting tool 4, and is performed in a state where the cutting tool 4 is attached to the main shaft 3. The cutting tool 4 before this molding is performed
Is molded by a tool maker, but a runout occurs due to a rotation error of the spindle 3, a chuck mounting error, and the like. This run-out is removed in this step S3 before processing.

Next, a tool shape remeasurement step S4 is performed. In step S4, the tool length and the tool diameter of the formed cutting tool 4 are measured again with the cutting tool 4 attached to the spindle 3, and the tool shape data of the control unit is rewritten. This tool shape data is for the next processing and has extremely high accuracy. Subsequent to step S4, a processing step S5 for processing the work is performed. In this step S5, the work is processed with high accuracy by the tool trajectory control program in which the latest tool shape data is added.

After that, when the predetermined machining time or the number of machining is reached in the tool shape measuring step S6,
With the cutting tool 4 still attached to the spindle 3, the tool shape is measured again to confirm the degree of tool damage. Then, in the tool re-grinding step S7, the cutting tool 4 is re-shaped. In this step S7, the amount of grinding is determined from the degree of tool damage, and re-grinding of the tool, that is, re-shaping, is performed with the cutting tool 4 attached to the spindle 3.

After the tool regrinding step S7, a used tool shape remeasurement step S8 is executed. In this step S8, the tool length and tool diameter after regrinding are measured with the cutting tool 4 attached to the spindle 3, and the tool shape data in the control unit is rewritten. Then, in the processing step S9,
Machining is performed by a tool trajectory control program modified based on the latest tool shape data. Then, step S
Returning to step 6, steps S6, S7, S8 and S9 are executed again. Then, after this, steps S6 to S9 are repeatedly executed. When the tool length and the tool diameter are equal to or less than the predetermined length, it is determined that the cutting tool 4 has reached the end of its life,
Replace with another cutting tool 4 in the automatic tool changer unit 5.
Then, step S1 and subsequent steps are performed again.

Thus, in this numerically controlled machine tool,
With the cutting tool 4 attached to the spindle 3, measurement and grinding are repeated. In the case of an end mill, the cutting edge is shaped and ground according to the most worn cutting edge (= the recessed edge), but the shaping set in the control section. It may be performed according to the conditions. The cutting fluid used for forming the cutting tool 4 is the same as that used for processing the workpiece, but another oil suitable for each processing may be used.
Further, the dressing of the grindstone 8 as the grinding tool is automatically performed in the numerically controlled machine tool, but it may be performed outside the machine tool. Further, in this embodiment, the cutting edge of the conventional end mill attached to the main shaft oscillates at 10 to 30 μm, whereas it becomes 2 to 3 μm.
It is possible to control the entry and exit of m. Further, when the cutting tool 4 such as an end mill is ground, the margin is about 10 μm, and even if it is reground about 100 times, the margin is only about 1 mm, which means that the cutting tool 4 can be used for a long time while being reground. .

This embodiment has the effects of high precision, labor saving, and resource saving. That is, when the cutting edges of the cutting tool 4 are aligned, the cutting amount shared by each cutting edge becomes uniform, and highly accurate and stable machining is performed. If the cutting edges are uneven, the short cutting edges do not contribute to the cutting. Moreover, since the outer diameter and the length of the cutting tool 4 are measured and corrected, the processing dimension accuracy is improved. Further, since the regrinding is performed before the wear becomes too large, the tool deflection can be suppressed to a low level. This is because there is a phenomenon that when the amount of wear increases, the back force increases and the tool deflection increases. In the drill, if the tool center and the rotation center do not match, a whirling phenomenon causes an error in the hole position. In addition, the rotation runout of the drill is
What is called an enlargement margin, that is, a hole having a diameter larger than the drill diameter is formed, but in this embodiment, the enlargement margin hardly occurs.

When the cutting tool 4 is formed in the numerically controlled machine tool, it is not necessary to replace the spare tool, so that the numerically controlled machine tool can be operated continuously and unmanned. Furthermore, throwaway (disposable) tools are often used because they have the advantage of eliminating the need for troublesome tool re-grinding, but these throwaway tools have high tool costs and rare metals such as tungsten. Will be thrown away, which is a resource problem. On the other hand, in this embodiment, for example,
If the cutting tool 4 is used while regrinding 10 μm at a time, regrinding 100 times results in a reduction of only 1 mm, which is a resource saving.

Although the above-described embodiment is an example of a preferred embodiment of the present invention, the present invention is not limited to this, and various modifications can be made without departing from the spirit of the present invention. is there. For example, the present invention can be applied to one in which the cutting tool 4 is replaced manually instead of automatic replacement, or a combination of automatic and manual. However, the present invention
It is suitable for use in a machining center with an automatic tool change function for machining parts that require micron-order accuracy.

Although the numerically controlled machine tools of the above-described embodiments are controlled by 5 axes including one axis of the on-machine grinding unit 9, the number of axes can be less than 5 or 6 or more. . When the number of axes is 5 or more, it is possible to form a complicated cutting tool 4 such as an end mill. Further, the cutting tool 4 may be molded with higher accuracy by measuring the wear amount and shape of the grindstone 8.

Further, it is possible to adopt a method of forming the tool only when the amount of wear of the cutting tool 4 has reached a predetermined value or more as a result of measurement after processing. Further, as the timing of forming the tool, various timings can be selected, such as when the cutting tool 4 is attached to the spindle 3, or during the waiting time for machining the workpiece, that is, the setting time of the workpiece. Moreover, it becomes more preferable to combine them. When tool forming is performed at appropriate intervals in this way, the cutting tool 4 can always maintain a sharp cutting edge and the like, so that the processing quality is stable. When only the tip of the cutting tool 4 is worn, the tip can be ground and removed from the cutting edge portion to form the tool without reducing the tool diameter.

Although each of the above-described embodiments uses the table type machining center, it can be applied to a pallet type. In that case, the on-machine measuring unit 7 and the on-machine grinding unit 9 may be placed on a pallet, respectively, and the pallet may be brought to the position of the spindle 3 if necessary. Further, the on-machine measurement unit 7 may be downsized and may be mounted on the on-machine grinding unit 9 or integrated with it. Further, the on-machine measuring unit 7 and the on-machine grinding unit 9 may be arranged so as to face each other with the main shaft 3 interposed therebetween, instead of being arranged on one side of the main shaft 3.

If the molding is not interrupted during the processing but is interrupted during the processing, the processing efficiency will be slightly reduced. In order to avoid this, a tool forming means for forming the cutting tool 4 is provided in the machine tool, for example, in the automatic tool changer unit 5, and the forming operation of the cutting tool 4 removed from the spindle 3 is referred to as a work processing operation. It may be performed in parallel. In this way, the time during which the forming work occupies the main shaft 3 becomes zero, and the work machining efficiency does not decrease.

[0042]

As described above, claims 1 and 2
In the described numerically controlled machine tool, since the cutting tool is formed with the cutting tool attached to the spindle, the troubles caused by tool damage during unattended operation are eliminated, and long-term unattended operation becomes possible. Improves operating rate. In addition, the runout of the cutting tool is eliminated, and the machining accuracy is greatly improved. Moreover, in the past, special expensive tools and long-time adjustments were required to eliminate this runout, but such tools are no longer required, and cost reduction and molded cutting can be achieved. The tool installation process is not required, and the processing time can be shortened.

In addition, according to the third aspect of the present invention, since the cutting tool is formed by using the waiting time for processing the workpiece, the processing time is increased even if the tool is formed. Almost never.

Further, in the invention according to the fourth aspect, unmanned operation for a long time is possible, and the cutting tool can be formed without lowering the working efficiency.

[Brief description of drawings]

FIG. 1 is a perspective view of an embodiment of a numerically controlled machine tool of the present invention.

FIG. 2 is a side view of an on-machine measurement unit used in the numerically controlled machine tool of FIG.

FIG. 3 is a diagram for explaining a method of using the on-machine measuring unit in FIG. 2, in which a solid line shows a case of measuring the outer circumference of the cutting tool, and a dotted line shows a case of measuring the bottom of the cutting tool.

FIG. 4 is a sectional view taken along line IV-IV of FIG. 3;

5 is a side view of an on-machine grinding unit used in the numerically controlled machine tool of FIG. 1. FIG.

6 is a view seen from the left side of FIG. 5, and is a front view of a state in which a grindstone of the on-machine grinding unit is tilted.

FIG. 7 is a diagram for explaining a method of grinding the outer circumference of the cutting edge of the end mill using the on-machine grinding unit of FIG.

FIG. 8 is a view for explaining a method of grinding the bottom of the cutting edge of the end mill by using the on-machine grinding unit of FIG.

FIG. 9 is a diagram for explaining an operation sequence of the numerically controlled machine tool of FIG. 1.

[Explanation of symbols]

 1 Main Body 2 Spindle Head 3 Spindle 4 Cutting Tool 5 Automatic Tool Changer Unit 6 Work Stand 7 On-machine Measuring Unit 8 Grinding Stone (Grinding Tool) 9 On-machine Grinding Unit (Tool Forming Means) 10 Guide

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Yuichi Usui 1-2 Namiki, Tsukuba-shi, Ibaraki Institute of Mechanical Engineering, Industrial Technology Institute (72) Inventor Chiaki 6-6 Takashima Sangyo Co., Ltd. 5695, Kanazawa, Chino, Nagano Prefecture Inside the Mikano Factory (72) Inventor Yoshinori Sakurai 5695, Kanazawa, Chino City, Nagano Prefecture 6 Inside the Mikano Factory, Takashima Sangyo Co., Ltd.

Claims (4)

[Claims] 1. A numerically controlled machine tool having a tool forming function, comprising a tool forming means for forming a cutting tool attached to a spindle in an attached state in a numerically controlled machine tool having an automatic tool changer. machine. 2. A numerically controlled machine tool for machining a workpiece by exchanging a cutting tool attached to a spindle, comprising tool forming means for shaping the cutting tool attached to the spindle, the workpiece being machined. A numerically controlled machine tool with a tool forming function, characterized in that the forming means is brought to a position of the work piece when not processing, and the cutting tool is formed. 3. The numerical value with a tool forming function according to claim 1, wherein the cutting tool is formed during a waiting time for processing when a workpiece is processed by the cutting tool. Control machine tools. 4. A numerical control machine tool having an automatic tool changer, wherein a cutting tool detached from a spindle is molded by a tool molding means provided in the machine tool. Machine Tools.