Interchangeable head cutting tool

Abstract

This invention provides a head-exchangeable cutting tool that offers stable tightening force on the head and high combined rigidity. [Solution] The head-exchangeable cutting tool according to the present invention comprises a toolbar 10, a head 20, and a screw 30. A positioning hole 11 is provided on the end face of the toolbar 10, and the positioning hole 11 has a polygonal shape. The positioning hole 11 includes a bottom portion provided as two positioning slots 111 that are symmetrical and jointly form a V shape, and has a high-speed positioning function. A positioning shaft 22 is installed on one end of the head 20, and the positioning shaft 22 has a polygonal shape. The positioning shaft 22 includes a bottom portion provided as two positioning seats 221 that are symmetrical and jointly form a V shape. The screw 30 has a conical head 31 at its lower end.

Description

TECHNICAL FIELD

[0001] The present invention relates to an improved structure of a cutting tool. More specifically, the head structure of the cutting tool is designed to be replaceable, and the head and the tool shank of the cutting tool relate to a head-replaceable cutting tool having a stable locking structure, a high-precision positioning structure, and a structure with high torque resistance rigidity. BACKGROUND ART

[0002] Conventional cutting tools, in particular, have a design where the cutting tool head is detachable, allowing cutting work to be performed by changing blades with different functions. For example, as shown in Figure 15, the interchangeable chamfering knife 7 comprises a tool handle 71 and a head 72, with an insertion part 721 provided at one end of the head 72, which is inserted to correspond to the insertion slot 711 of the tool handle 71. The head 72 is positioned within the insertion slot 711 of the tool handle 71 by a locking mechanism 73, and both the insertion part 721 and the insertion slot 711 are designed to be circular. Also, for example, Figure 16 is a schematic diagram of the insertion part 721 and the insertion slot 711 being locked together, and is a schematic diagram in which the gap that occurs when they are combined is intentionally enlarged. When the insertion part 721 is tightened by the locking mechanism 73, a tightening force F is generated on the insertion part 721. As shown by the black arrows, there is a corresponding reaction force R at the position where the insertion part 721 and the insertion slot 711 on the corresponding surfaces are combined and in contact. As indicated by the white arrow, the gap that occurs when the insertion part 721 and the insertion slot 711 are assembled by applying a force to the insertion part 721 with the tightening force F is located on the side of the tightening force F. Therefore, when the tightening force F is generated by tightening the insertion part 721 with the locking device 73, the gap causes the insertion part 721 to deflect and rotate at a small angle, resulting in an error in the assembly accuracy of the insertion part 721 and the insertion slot 711. More specifically, if the insertion part 721 is locked with only one corresponding set of tightening force F and reaction force R, the tightening force is insufficient, and when the tool is subjected to cutting force, a torsional torque T is generated in the insertion part 721. When the torque T becomes greater than the tightening force F, the insertion part 721 rotates in a sliding manner, affecting the cutting accuracy of the tool and the service life of the tool. Increasing the number of locking members often solves the problem of the part rotating in a sliding manner, but it was not possible to improve the assembly accuracy of the insertion section 721 and the insertion slot 711.

[0003] Figure 17 shows a modular lathe tool, comprising a lathe toolbar 81, a lathe tool holder 82, and at least one clamping fixture 83. The end face of the lathe toolbar 81 is provided with an inwardly facing insertion slot 811, and an insertion shaft 821 is installed axially in the lathe tool holder 82, which is inserted into the insertion slot 811 and locked in place by the clamping fixture 83. Similarly, both the insertion shaft 821 and the insertion slot 811 are designed to be circular in shape, and if the conditions occurring in the assembly structure are the same as those for the interchangeable chamfering knife 7 (see Figures 15 and 16), the insertion portion 721 is locked by the corresponding clamping force F and reaction force R, resulting in insufficient clamping force and a disadvantage of reduced assembly stability.

[0004] Figure 18 shows a lathe tool changing device 9, which comprises a front lathe tool holder 91 and a rear lathe tool holder 92, locked by a screw 93. The rear end of the front lathe tool holder 91 is machined into a square shape and has a protruding slide rail 911, while the front end surface of the rear lathe tool holder 92 is provided with a slide groove 921 of a corresponding shape facing inward. The tool connection structure belongs to the square design and has suitable torque resistance strength, but when locked by tightening with the screw 93 after assembly, a tightening force F and a reaction force R are generated along the same axis. As shown in Figure 16, the tightening force F and reaction force R are generated in a corresponding manner, but there is a limit to the tightening force, and when heavy cutting is performed, there is a risk of vibration due to the gap created when the connection structure is assembled. [Overview of the project] [Problems that the invention aims to solve]

[0005] Figure 16 shows various combination structures of conventional interchangeable head tools. The circular connection assembly structure has high assembly accuracy errors, and when locked with screws, it only has a tightening force F and a reaction force R, resulting in insufficient tightening force and low torque resistance strength. There are also square connection structures that have suitable torque resistance strength, but when locked by tightening with screws after assembly, tightening force and reaction force are generated along the same axis. Although only the tightening force F and reaction force R are generated in a corresponding manner, there is a limit to the tightening force, and when performing heavy cutting, there is a risk of vibration due to the gap created when the connection structure is assembled, and there are many shortcomings that need improvement. [Means for solving the problem]

[0006] To solve the above problems, a head-exchangeable cutting tool according to one embodiment of the present invention comprises a toolbar, a head, and a screw. The end face of the toolbar is provided with an inwardly facing positioning hole, which is polygonal in shape. The positioning hole includes a bottom portion that is symmetrical and jointly forms a V-shape with two positioning slots, providing a high-speed positioning function. Both sides of the middle portion of the positioning hole are provided with two vertically symmetrical vertical edges. The top of the positioning hole is provided as a horizontal upper flat edge. The bottom of the positioning hole is provided as a horizontal lower flat edge. A housing hole is provided adjacent to the end of the positioning hole opposite the head. A screw hole is drilled in the upper surface of the toolbar at the location corresponding to the upper flat edge of the positioning hole. A positioning shaft is installed at one end of the head, and the positioning shaft is provided in a polygonal shape. The positioning shaft has a symmetrical shape and includes a bottom portion that is provided as two positioning seats that jointly form a V shape. Both sides of the middle portion of the positioning shaft are provided as two vertical surfaces that are symmetrical in the vertical direction. The top of the positioning shaft is provided as a horizontal load surface. The bottom of the positioning shaft is provided as a horizontal flat surface. A bending prevention shaft is connected to the end of the positioning shaft opposite to the head, and a tapered hole is provided in the load surface. The screw has a conical head at its lower end. [Effects of the Invention]

[0007] As the present invention is configured as described above, it produces the following effects. The positioning holes of the toolbar and the positioning shaft of the head according to the present invention are provided with a polygonal shape, and the shapes of both correspond and have a precise combination tolerance. The polygonal shape restricts the degree of freedom of rotation of the head and toolbar, and the polygonal shape also has the effect of providing suitable torsional and shear resistance stress. When the positioning shaft is tightened with a screw, a tightening force F is generated, and at the same time, a corresponding reaction force R is generated on the contact surface of the flat surface at the bottom and the V-shaped positioning seat, forming a concentric force system, which has the progressive effect of making the tightening force on the head very stable and increasing the combined rigidity.

[0008] Other features of the present invention will be made clearer by description in this specification and the drawings. [Brief explanation of the drawing]

[0009] [Figure 1] This is an exploded perspective view of a head-exchangeable cutting tool according to one embodiment of the present invention. [Figure 2] This is a front view showing the toolbar of a head-exchangeable cutting tool according to one embodiment of the present invention. [Figure 3] This is a rear view showing the head of a head-exchangeable cutting tool according to one embodiment of the present invention. [Figure 4] This is a longitudinal cross-sectional view of a head-exchangeable cutting tool according to one embodiment of the present invention, in a combined state. [Figure 5] This is a cross-sectional view in the short direction of Figure 4. [Figure 6] This is a schematic diagram of the force applied when the positioning axis of the head according to one embodiment of the present invention is locked with a screw. [Figure 7] This is a schematic diagram of a modified shape of the positioning hole in a toolbar according to one embodiment of the present invention, and a circular positioning shaft is covered, showing the force applied when tightening the screw. [Figure 8] This is a combined cross-sectional view showing an example in which a collet chuck head according to another embodiment of the present invention is applied to an ER toolbar. [Figure 9] Figure 8 is a front view showing the ER toolbar. [Figure 10] This is an inclined view showing a tool length positioning rod according to another embodiment of the present invention. [Figure 11] A cross-sectional view showing a tool length positioning rod according to another embodiment of the present invention. [Figure 12] This is a combined cross-sectional view showing an example in which a tool length positioning rod according to another embodiment of the present invention is applied to a collet chuck head and an ER toolbar. [Figure 13] Figure 12 shows an application example where a tool and tool length positioning mechanism are installed. [Figure 14] This is a schematic diagram showing a state in which a coolant is sprayed from inside the ER toolbar toward the tool according to another embodiment of the present invention. [Figure 15] This is a cross-sectional view showing a combination of conventional interchangeable chamfering knives. [Figure 16] This is a schematic diagram showing how the assembly of a conventional tool handle and head can withstand the tightening force of a screw. [Figure 17] This is a cross-sectional view showing a conventional combination type lathe tool. [Figure 18] This is an exploded perspective view showing how conventional modular lathe tools are connected in a rectangular shape. [Mode for Carrying Out the Invention]

[0010] Hereinafter, the present invention will be described through embodiments, but the following embodiments do not limit the invention according to the claims. Further, not all combinations of features described in the embodiments are necessarily essential to the solving means of the invention. In the direction of the rotation axis of the cutting tool, the end on the head side or the collet chuck head side is defined as the front end, and the end on the side opposite to the head or the collet chuck head is defined as the rear end.

[0011] First, the best mode for carrying out the present invention will be described in detail with reference to Figures 1 to 4.

[0012] The head-replaceable cutting tool according to the present invention mainly includes the following members, and the configuration of each member will be described.

[0013] <Tool bar 10> A positioning hole 11 is provided inward on the end face, the positioning hole 11 is provided in a polygonal shape, and includes a bottom portion provided as two positioning slots 111 that are symmetrical and jointly present a V-shape. Both sides of the intermediate portion are provided as two vertical edges 112 that are symmetrical in the vertical direction, the top portion is provided as an upper flat side 113 that is horizontal, and the bottom portion is provided as a lower flat side 114 that is horizontal. A receiving hole 12 is provided in communication with the rear end of the positioning hole 11, a water passage hole 13 is provided in communication with the rear end of the receiving hole 12, and a threaded hole 115 is drilled at a position on the upper surface of the tool bar 10 corresponding to the upper flat side 113 of the positioning hole 11.

[0014] <Head 20> A blade 21 is locked in a tool holder at one end, and a positioning shaft 22 corresponding to the shape of the positioning hole 11 is installed at the other end of the head 20. The positioning shaft 22 is provided as a polygonal shape and includes a bottom portion which is provided as two positioning seats 221 that are symmetrical and jointly form a V shape. Both sides of the middle portion are provided as two vertical surfaces 222 that are symmetrical in the vertical direction, the top portion is provided as a horizontal load surface 223, and the bottom portion is provided as a horizontal flat surface 224. A bending prevention shaft 23 is connected to the rear end of the positioning shaft 22, and a tapered hole 225 is provided in the load surface 223 of the positioning shaft 22.

[0015] <Screw 30> The lower end of the screw 30 is provided with a conical head 31 that has a shape corresponding to the tapered hole 225 of the head 20.

[0016] The position of the tapered hole central axis 226 in the tapered hole 225 is slightly offset from the screw hole central axis 116 in the screw hole 115 of the toolbar 10. The tapered hole central axis 226 is positioned slightly in front of the screw hole central axis 116 and, after being tightened by the screw 30, generates an inward tightening effect relative to the head 20.

[0017] Refer to Figures 4 and 5 together. The positioning shaft 22 of the head 20 penetrates into the positioning hole 11 of the toolbar 10, and the bottom of the positioning hole 11 is provided as two positioning slots 111 that are symmetrical and jointly form a V shape. The V-shaped positioning slots 111 have the characteristic of restricting the X and Y axes, and are capable of stable, high-speed, and accurate positioning. The positioning shaft 22 also has a polygonal shape accordingly, and the positioning seat 221 at the bottom is symmetrical and jointly forms a V shape. Once the positioning seat 221 penetrates into the positioning slot 111, the head 20 is positioned stably and accurately, and the position of the cutting edge of the blade 21 is immediately and accurately positioned.

[0018] The head 20 is constrained in the Z-axis mainly by the tightening effect of the screw 30. As shown in Figures 1 to 4, there is a slight offset between the position of the tapered hole central axis 226 located in the tapered hole 225 and the position of the screw hole central axis 116 located in the screw hole 115 of the toolbar 10. When the conical head 31 at the lower end of the screw 30 abuts against the tapered hole 225, an inward and downward force is generated, and as the end faces of the head 20 and toolbar 10 are gradually tightened, a restraining and locking effect is generated with respect to the Z-axis.

[0019] The main function of the anti-bending shaft 23 is to provide bending moment resistance to the head 20. When the anti-bending shaft 23 enters the housing hole 12 of the toolbar 10, the length to which the head 20 enters the toolbar 10 increases. When cutting with the head 20, the increased ratio of the supported length increases the rigidity of the head 20, and at the same time, the area for stress distribution also increases, effectively enhancing the head 20's ability to withstand cutting torque.

[0020] The toolbar 10 according to the present invention has a positioning hole 11 that is polygonal in shape, and in this embodiment, it is a hexagonal hole. The head 20 has a positioning shaft 22 that is polygonal in shape, and the shapes of the two correspond and have a precise combination tolerance. The polygonal shape limits the degree of freedom of rotation of the head 20 and toolbar 10, and the polygonal shape has suitable torsional resistance stress and shear resistance stress. The positioning seat 221 and positioning slot 111 are designed in a V shape, which has the effect of positioning the head 20 stably, quickly and accurately, and the cutting edge position of the blade 21 is positioned immediately and accurately, eliminating the need to readjust the cutting edge position.

[0021] Referring to Figures 4 to 6, when the positioning shaft 22 of the head 20 is tightened with the screw 30, the screw 30 generates a tightening force F on the load surface 223 of the positioning shaft 22, as indicated by the black arrows. At the same time, a corresponding reaction force R is generated on the contact surface between the bottom flat surface 224 and the V-shaped positioning seat 221, as indicated by the white arrows. In this way, a concentric force system is formed, the tightening force on the head 20 is very stable, and the rigidity of the combination is increased.

[0022] Figure 7 shows an embodiment of the structure in which the shape of the positioning hole 11 of the toolbar 10 of the present invention has been changed, and the bottom of the positioning slot 111 has been changed from the flat side 114 at the bottom of Figure 2 to the arc end 117. This cylindrical positioning shaft 24 receives the lock of the concentric force system of three forces, including the screw 30 and the V-shaped positioning slot 111, and the cylindrical positioning shaft 24 is positioned quickly and accurately, and the effect of being stably locked by the concentric force system of the three forces is produced. The screw 30 is shown in Figure 1.

[0023] Embodiments of the present invention apply a combination of a lathe tool head and toolbar to clamp cutting tools (e.g., ER tools) using an elastic collet, in addition to lathe tools. As shown in Figures 8 and 9, the internal structure of the toolbar 10 in Figure 1 is implemented in the ER toolbar 4. A positioning hole 41 provided on the front end face of the ER toolbar 4 is provided in a polygonal shape, and a collet chuck head 5 is housed in the positioning hole 41 and locked by a screw 40. A positioning shaft 51 is provided at one end of the collet chuck head 5, and the positioning shaft 51 is provided in a polygonal shape. A bending prevention shaft 52 is connected to the rear end of the positioning shaft 51. A tapered hole 512 is provided on the load surface 511 of the positioning shaft 51, and another tapered hole 53 is provided on the end face of the collet chuck head 5. As the tapered hole 53 penetrates the elastic collet 54 and is locked by the nut 55, a cutting tool is formed that has an elastic collet 54 and a circular tool handle capable of gripping drills, center drills, end mills, threading tools, etc.

[0024] The collet chuck head 5 does not have cooling fluid passages, and external cooling is used for punching, chip removal, and cooling of the workpiece and tool, but the effectiveness of the external cooling method was low. In particular, chip removal and cooling were difficult when cutting deep blind holes, the cutting blade easily overheated, reducing machining efficiency, and chips rubbed against the surface of the tool and workpiece, reducing machining accuracy.

[0025] In addition, since the tools used in NC machining centers all have different lengths, each tool's length is compensated for, and the machining depth of each tool is made accurate to prevent tool collisions and slippage during machining. A commonly used tool length compensation device is the Z-axis setter, but operators sometimes make mistakes when entering the values ​​after measurement, resulting in tool collisions and slippage. As a result, the cutting performance of the tool becomes sluggish, and when changing tools, the length to which the tool should be loaded into the toolbar is not fixed, requiring tool length compensation every time the tool is changed.

[0026] Refer to Figures 10 and 11 together. The tool length positioning rod 6 according to the present invention comprises a screw head 61, a positioning pin 62 installed at the front end of the tool length positioning rod 6, a drive hole 63 provided inside one end of the screw head 61, a hexagonal drive hole 63, a water passage hole 64 passing through the tool length positioning rod 6, and a side outlet 65 provided at the end of the positioning pin 62 and passing through the end of the water passage hole 64.

[0027] Refer to Figure 12. An internal threaded hole 521 is provided at the rear end of the anti-bend shaft 52 of the collet chuck head 5, and another housing hole 522 is provided at the bottom of the internal threaded hole 521. The housing hole 522 penetrates to a tapered hole 53, and a positioning pin 62 is inserted into the housing hole 522, locking the front end of the ER toolbar 4 to the collet chuck head 5. The tool length positioning rod 6 according to the present invention is screwed into the internal threaded hole 521 at the rear end of the anti-bend shaft 52, and the front end of the positioning pin 62 of the tool length positioning rod 6 approaches the rear end of the elastic collet 54, and the tool length positioning rod 6 can rotate forward or backward to change the position of the front end of the positioning pin 62. Referring to Figure 13, the tool 500 penetrates into the elastic collet 54 and is locked by a nut 55.

[0028] Refer to Figures 11 and 13. The tool length positioning rod 6 has anaerobic adhesive applied to the screw head 61. As it rotates, the front end of the positioning pin 62 comes into contact with the toolbar 501 of the tool 500 (see Figure 13). Once the anaerobic adhesive dries and hardens, the position of the tool length positioning rod 6 is fixed. In this way, the position of the tool 500 can be fixed, and each time the tool 500 is replaced with a tool of the same size and length, or each time the disposable blade of the tool is replaced, the length and position of the tool 500 are fixed only by bringing the toolbar 501 of the tool 500 into contact with the front end of the positioning pin 62 when reloading the tool 500 into the ER toolbar 4. Therefore, there is no need to readjust the tool length position using a Z-axis setter, saving time spent on tool length correction, and also preventing situations where the tool spins freely or collides due to data input errors when correcting the tool length.

[0029] Refer to Figure 14. Coolant is injected from the rear end of the ER toolbar 4 (indicated by the arrow in the figure), and the inside of the tool length positioning rod 6 enters the internal threaded hole 521 at the rear end of the anti-bending shaft 52. The coolant flows out from the side outlet 65 at the end of the water passage hole 64 toward both sides and turns into the water jet hole 541 of the elastic collet 54. Finally, it is ejected from the end of the water jet hole 541 toward the tool 500, jetting to cool the blade portion of the tool 500 and the workpiece, while simultaneously washing away chips. Also, since the coolant flows out from the inside of the ER toolbar 4, the ER toolbar 4 and the elastic collet 54 are cooled first, and then the toolbar 501 of the tool 500 is cooled. Therefore, when cutting with the tool 500, heat is not conducted to the ER toolbar 4, the ER toolbar 4 is not affected by thermal expansion and cooling contraction, and the cutting accuracy is not affected.

[0030] Refer to Figures 1, 3, and 13 together. As can be seen from the above description, the positioning holes 11 of the toolbar 10 and the positioning shaft 22 of the head 20 according to the present invention are provided in a polygonal shape. This limits the degree of freedom of rotation of the head 20 and toolbar 10, provides suitable torsional and shear resistance stresses, provides a precise and repeatable positioning function to the contact surface of the V-shaped positioning seat 221, and provides a very stable clamping effect due to the clamping force on the head 20. The head 20 is designed with different structures depending on the type of tool 500 to be clamped. For example, it clamps round bar tools, disposable blade end mills, drills, lathe tools, etc. In addition, the tool length positioning rod 6 is fixed in position after the anaerobic adhesives have dried and hardened, and is restricted so that the length and position of the tool 500 are fixed. By using a Z-axis setter, there is no need to readjust the tool length position, saving time spent on tool length adjustments. Furthermore, there is no need to train operators on tool change procedures, saving time on tool changes and achieving numerous creative benefits such as increased cutting efficiency.

[0031] The present invention is not limited to the embodiments described above, and various modifications are possible within the scope of the claims. Embodiments obtained by appropriately combining the technical means disclosed in different embodiments are also included in the technical scope of the present invention. [Explanation of Symbols]

[0032] 10 Toolbar 11 Positioning holes 111 Positioning slots 112 Vertical Edge 113 Upper flat edge 114 Lower flat edge 115 screw holes 116 Screw hole center axis 117 Arc ends 12 containment holes 13 Water passage holes 20 heads 21 Blades 22 Positioning axis 221 Positioning seat 222 Vertical plane 223 Load-bearing surface 224 Flat surface 225 Tapered hole 226 Tapered hole center axis 23. Bending prevention shaft 24 Positioning axes 30 screws 31 Conical head 4 ER Toolbar 40 screws 41 Positioning holes 5 Collet Chuck Heads 500 Tools 501 Toolbar 51 Positioning axis 511 Load surface 512 Tapered hole 52 Bending prevention shaft 521 Internal threaded hole 522 Intake holes 53 Tapered hole 54 Elastic Collet 541 Fountain hole 55 Nut 6. Tool length positioning rod 61 Screw head 62 positioning pins 63 Drive holes 64 Water passage holes 65 Side outlet 7. Interchangeable chamfering knife 71 Tool Handles 711 Insertion Slots 72 heads 721 Insertion part 73 Locking tools 81 Lathe Toolbar 811 Insertion Slots 82 Lathe Tool Holder 821 Insertion shaft 83 Fastening and securing devices 9. Lathe tool changer 91 Front Lathe Tool Holder 911 Slide Rail 92 Rear Lathe Tool Holder 921 sliding groove 93 screws F Tightening force R reaction force T Torque XX axis YY axis ZZ axis

Claims

1. The end face is provided with an inward-facing positioning hole, the positioning hole is provided in a polygonal shape and includes a bottom portion that is provided as two positioning slots that are symmetrical and jointly form a V shape, both sides of the middle portion of the positioning hole are provided as two vertical edges that are symmetrical in the vertical direction, the top of the positioning hole is provided as an upper flat side that is horizontal, and a screw hole is drilled in the upper surface of the toolbar corresponding to the upper flat side, A positioning shaft is provided at one end, the positioning shaft is provided in a polygonal shape and includes a bottom portion which is provided as two positioning seats that are symmetrical and jointly form a V shape, both sides of the middle portion of the positioning shaft are provided as two vertical surfaces which are symmetrical in the vertical direction, the top of the positioning shaft is provided as a horizontal load surface, the bottom of the positioning shaft is provided as a horizontal flat surface, and the load surface has a tapered hole provided in the head, A screw with a conical head at its lower end, A head-exchangeable cutting tool characterized by having the following features.

2. The head-exchangeable cutting tool according to claim 1, characterized in that the bottom of the positioning hole is provided as an arc end.

3. The head-exchangeable cutting tool according to claim 1, characterized in that the bottom of the positioning hole is provided as a lower flat side exhibiting a horizontal shape.

4. A housing hole is provided adjacent to the end of the positioning hole opposite to the head. A bending prevention shaft is connected to the end of the positioning shaft opposite to the head. The head-exchangeable cutting tool according to claim 1, characterized in that the housing hole is provided to correspond to the bending prevention shaft.

5. A head-exchangeable cutting tool equipped with a collet chuck head, A tapered hole is provided on one end face of the collet chuck head, and an elastic collet is inserted into the tapered hole and locked by a nut. A head-exchangeable cutting tool characterized in that a positioning shaft is installed at the other end of the collet chuck head, the positioning shaft is provided in a polygonal shape, a bending prevention shaft is connected to the end of the positioning shaft opposite to the collet chuck head, and another tapered hole is provided on the load surface of the positioning shaft and is locked by a screw.

6. The interchangeable head cutting tool according to claim 5, characterized in that the collet chuck head has an internal threaded hole at the end of the anti-bending shaft opposite to the collet chuck head, and a housing hole that penetrates to the tapered hole is provided at the bottom of the internal threaded hole.

7. A tool length positioning rod is screwed into the internal threaded hole located at the end of the anti-bending shaft opposite to the collet chuck head. The head-exchangeable cutting tool according to claim 6, characterized in that the tool length positioning rod comprises a screw head, a positioning pin installed at the end of the tool length positioning rod on the collet chuck head side, a drive hole having a hexagonal shape and installed inside one end of the screw head, a water passage hole through which the tool length positioning rod passes, and a side outlet provided at the end of the positioning pin and passing through the end of the water passage hole.

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