High-speed cnc spindle high-precision machining automatic tool changing method and tool holder sleeve

Abstract

A high-speed CNC spindle high-precision machining automatic tool changing method and tool holder, wherein the method comprises the following steps: S1, sending a tool changing instruction; S2, the sensor detects whether there is a tool, if yes, enter S3 step, if no, enter S4 step; S3, perform the tool returning action; S4, perform the tool grabbing action; S5, align the spindle with the respective tools pre-installed in the tool holder; S6, the Z-direction driving mechanism drives the spindle to move downward, so that the reference surface H of the lock mouth in the spindle is in contact with the positioning surface F of the positioning clamp of the corresponding tool; S7, the spindle cylinder is depressurized, the spindle disc spring is stretched to drive the driving rod to rise, the lock mouth rises with the driving rod, and the lock mouth is retracted to clamp the upper part of the tool; S8, the spindle rises synchronously with the tool that has been grabbed, and the tool changing is completed. The present application has the advantages that the lock mouth will not produce relative sliding, the positioning clamp structure is compact and small, and the stability is better during high-speed operation.

Description

Technical Field

[0001] This invention relates to the field of CNC machine tools, and in particular to an automatic tool changing method and tool holder for high-speed CNC spindle high-precision machining. Background Technology

[0002] Chinese patent document CN 114918710 A discloses an automatic tool changing method and machine tool for a single-drive multi-spindle CNC machine tool. The automatic tool changing method includes the following steps: S1, sending a tool changing command; S2, the sensor detects whether a tool is present. If present, proceed to step S3; otherwise, proceed to step S4; S3, performing a tool return action; S4, performing a tool grabbing action; S5, aligning all spindles with their respective tools pre-installed in the tool holders; S6, the Z-axis drive mechanism drives all spindles downward, so that the reference surface of all spindles contacts the positioning surface of the corresponding tool's positioning clamp; S7, the spindle cylinder depressurizes, the spindle disc spring extends, driving the drive rod to rise, the locking jaws follow the drive rod to rise, and the locking jaws retract to clamp the upper part of the tool; S8, the Z-axis drive device drives all spindles and the grabbed tools to rise synchronously, completing the tool changing.

[0003] The existing automatic tool changing method and machine tool for single-drive multi-spindle CNC machine tools have the following drawbacks in practical use: In step S6, the reference surfaces of all spindles are brought into contact with the positioning surfaces of the corresponding tool's locating clamps. However, in actual use, the upper part of the tool extends into the locking jaw, the drive rod drives the locking jaw to rise, and the locking jaw retracts to clamp the upper part of the tool. The Z-axis drive device drives the spindle and the gripped tool to rise synchronously. Because the reference surface of the spindle is in contact with the positioning surface of the locating clamp, when the locking jaw continues to pull upwards, the reference surface of the spindle and the positioning surface of the locating clamp push against each other, preventing the tool from rising further. This causes relative movement of the locking jaw, affecting the tool's swing arm, and also causes the tool and locking jaw to constrain each other, resulting in misalignment and affecting the machine tool's operation. Furthermore, the locating clamp structure in this method is complex and large, making it prone to shaking and instability on high-speed machine tools. Summary of the Invention

[0004] To address the aforementioned issues, this invention provides a high-speed CNC spindle high-precision machining automatic tool changing method and tool holder that prevents relative sliding of the locking mouth, ensures a more centered position of the tool and locking mouth, features a compact positioning clamp structure, and achieves better dynamic balance during high-speed operation.

[0005] The technical solution of this invention is: to provide an automatic tool changing method for high-speed CNC spindle high-precision machining, comprising the following steps: S1, Send tool change command; S2. The sensor detects whether there is a tool on the spindle. If there is, proceed to step S3; otherwise, proceed to step S4. S3. Perform the knife return action; S4. Perform the knife-grabbing action, and grasp the knife according to the following steps; S5. Move the spindle above the tool holder and align the spindle with the tool pre-installed in the tool holder. The tool has a blade and a tool holder. The tool holder includes a positioning clamp with an axial through hole and a tensioning member. The upper end of the positioning clamp is provided with a reference surface F. The clamp wall of the positioning clamp is provided with at least one upper opening groove and at least one lower opening groove. The upper opening groove and the lower opening groove are staggered so that the positioning clamp forms an elastic body. The tensioning member is sleeved outside the clamp wall of the positioning clamp. The positioning clamp and the tensioning member are coaxially arranged and used together to clamp the tool. The tool holder is coaxially positioned on the handle of the tool. S6, the Z-axis drive mechanism drives the spindle to move downward, so that the reference surface H of the locking nozzle inside the spindle contacts the positioning surface F of the corresponding tool positioning clamp. At the same time, under the action of the spindle cylinder built into the spindle, the drive rod moves downward, so that the locking nozzle located at the lower end of the drive rod opens, the upper part of the tool extends into the locking nozzle, the spindle disc spring located at the upper part of the drive rod is compressed, and the tool holder elastic body inside the tool holder is compressed under the action of the downward force of the corresponding tool. Under the action of the reaction force of the tool holder elastic body, the reference surface H of the locking nozzle is in close contact with the positioning surface F of the positioning clamp. S7. The spindle cylinder is depressurized, the spindle disc spring extends and drives the drive rod to rise, the locking nozzle follows the drive rod to rise, the locking nozzle retracts and clamps the upper part of the tool, keeping the reference surface H of the locking nozzle and the positioning surface F of the positioning clamp in close contact. The bore diameter D1 of the spindle is larger than the outer diameter D2 of the tool holder. When the locking nozzle rises, the positioning clamp and the tool can also rise within the bore diameter D1. The S8 and Z-axis drive devices drive the spindle to rise synchronously with the gripped tool, completing the tool change.

[0006] As an improvement to the present invention, it also includes step S9 and repeating steps S2-S8, thereby realizing the cyclic tool changing function in the machining process.

[0007] As an improvement to the present invention, step S3 includes the following steps: S31. Move the spindle above the tool holder so that the spindle is aligned with the empty space in the tool holder; S32. The Z-axis drive mechanism drives the spindle to move downward, and the tool on the spindle moves downward to a set position, so that the tool holder holds the positioning clamp on the tool, and the spindle stops moving downward; the spindle cylinder inside the spindle is inflated, the disc spring is pressed down, the drive rod moves downward, the locking mouth opens, and the locking mouth releases the upper part of the tool; S33, the spindle moves upward and disengages from the tool, completing the tool return.

[0008] As an improvement to the present invention, step S5 further includes a tool assembly step: S51. Place the positioning clamp in the special fixture. The upper end face of the positioning clamp is provided with the F reference surface to ensure that the relative position of the F reference surface and the special fixture is fixed. The tool holder is inserted into the center hole of the positioning clamp so that the relative distance between the E reference surface of the bottom surface of the tool and the F reference surface reaches a predetermined distance. The tensioning member is sleeved on the clamp wall of the positioning clamp and the tensioning member is moved upward. S52. Fix the positioning clamp to the tool holder to form the cutting tool.

[0009] Another technical solution of the present invention is: providing a tool holder, including a positioning clamp with an axial through hole and a tensioning member, wherein the upper end of the positioning clamp is provided with a B reference surface, and the clamping wall of the positioning clamp is provided with at least one upper opening groove and at least one lower opening groove, the upper opening groove and the lower opening groove are staggered so that the positioning clamp forms an elastic body, the tensioning member is sleeved outside the clamping wall of the positioning clamp, and the positioning clamp and the tensioning member are coaxially arranged and used together to clamp the tool.

[0010] As an improvement of the present invention, the tensioning element is a tensioning nut, the lower middle part of the clamping wall of the positioning clamp is provided with an external thread, the tensioning nut is sleeved on the outside of the clamping wall of the positioning clamp, the tensioning nut is provided with an internal thread that matches the external thread, the positioning clamp and the tensioning nut are coaxially arranged and used together to clamp the knife.

[0011] As an improvement of the present invention, the upper opening groove extends downward from the upper end face of the positioning clamp to near the lower end face of the positioning clamp, and the lower opening groove extends upward from the lower end face of the positioning clamp to near the upper end face of the positioning clamp.

[0012] As an improvement of the present invention, the positioning clamp includes a clamp cap and a clamp body, wherein the outer diameter of the clamp body gradually increases from bottom to top to form a conical surface.

[0013] As an improvement of the present invention, the inner wall of the tensioning nut is a conical inner wall that matches the conical surface of the clamping body.

[0014] As an improvement of the present invention, the clamp cap is a convex ring structure, and the outer diameter of the clamp cap is larger than the outer diameter of the clamp body.

[0015] As an improvement of the present invention, the tensioning component includes a tensioning sleeve and a tightening nut. The lower middle part of the clamping wall of the positioning clamp is provided with an external thread. The tensioning sleeve and the tightening nut are sequentially sleeved on the clamping wall of the positioning clamp. The tightening nut is provided with an internal thread that matches the external thread. The tightening nut is located below the tensioning sleeve and abuts against the lower end face of the tensioning sleeve. The positioning clamp, the tensioning sleeve, and the tightening nut are coaxially arranged and used together for the knife.

[0016] The core of this invention is as follows: First, when the Z-axis drive mechanism drives the spindle downward, the reference surface H of the locking nozzle inside the spindle contacts the positioning surface F of the corresponding tool positioning clamp. Second, the bore diameter D1 of the spindle is larger than the outer diameter D2 of the positioning clamp. When the locking nozzle rises, the tool and the positioning clamp also rise within the bore diameter D1 of the spindle. Thus, during the tool gripping action, when the Z-axis drive mechanism drives the spindle downward, the reference surface H of the locking nozzle inside the spindle contacts the positioning surface F of the corresponding tool positioning clamp. Simultaneously, when the drive rod inside the spindle moves downward, the locking nozzle located at the lower end of the drive rod opens, the upper part of the tool extends into the locking nozzle, the spindle disc spring located at the upper part of the drive rod is compressed, and the tool holder elastic body inside the tool holder is compressed under the downward force of the corresponding tool. Under the reaction force of the tool holder elastic body, the reference surface H of the locking nozzle contacts the positioning clamp. The positioning surface F of the positioning clamp is in close contact with the tool. Then, the spindle cylinder depressurizes, the spindle disc spring extends, driving the drive rod to rise. The locking nozzle follows the drive rod and rises, retracting to clamp the upper part of the tool, keeping the reference surface H of the locking nozzle in close contact with the positioning surface F of the positioning clamp. Since the bore diameter D1 of the spindle is larger than the outer diameter D2 of the positioning clamp, when the locking nozzle rises, the positioning clamp and the tool also rise within the bore diameter D1. In this way, even if the locking nozzle continues to pull upward, the reference surface H of the locking nozzle and the positioning surface F of the positioning clamp remain in close contact, and the positioning clamp and the tool can also move upward. The locking nozzle will not slide relative to the tool, and the position of the tool held by the locking nozzle will not move. The swing arm of the tool does not change, and the tool and the locking nozzle can remain centered. In addition, the positioning clamp in this invention is compact and small, and is not prone to shaking in high-speed machine tools, resulting in better stability. Attached Figure Description

[0017] Figure 1 This is a schematic diagram of one embodiment of the automatic tool changing method for high-precision machining of high-speed CNC spindles according to the present invention.

[0018] Figure 2 yes Figure 1 A schematic diagram of the steps involved in returning the knife.

[0019] Figure 3 yes Figure 2 A diagram illustrating the action of returning the knife.

[0020] Figure 4 This is a schematic diagram of the structure before tool changing in this invention.

[0021] Figure 5 This is a schematic diagram of the tool changing mechanism in this invention.

[0022] Figure 6 This is a schematic diagram of the tool changing process in this invention.

[0023] Figure 7This is a schematic diagram of the structure after the tool change is completed in this invention.

[0024] Figure 8 This is a schematic diagram of the tool assembly.

[0025] Figure 9 This is a three-dimensional exploded structural diagram of one embodiment of the blade clip of the present invention.

[0026] Figure 10 yes Figure 9 A frontal view diagram.

[0027] Figure 11 yes Figure 9 A schematic diagram of the fully assembled 3D structure.

[0028] Figure 12 yes Figure 11 A frontal view diagram.

[0029] Figure 13 yes Figure 12 Top view.

[0030] Figure 14 yes Figure 13 A cross-sectional view along the AA direction. Detailed Implementation

[0031] Please see Figures 1 to 3 , Figures 1 to 3 This discloses one implementation method for automatic tool changing in high-precision machining using a high-speed CNC spindle. The method includes the following steps: Please refer to [link to previous text]. Figure 1 ,: S1. The CNC device of the machine tool sends a tool change command; S2. The sensor on the machine tool detects whether there is a tool on the spindle. If there is, proceed to step S3; otherwise, proceed to step S4. In this embodiment, the sensor is an infrared sensor, which includes an infrared emitting tube and an infrared receiving tube. The infrared emitting tube and the infrared receiving tube are arranged opposite to each other. When the infrared light emitted by the infrared emitting tube can be received by the infrared receiving tube, it indicates that there is no tool at the lower end of the spindle; otherwise, it indicates that there is a tool at the lower end of the spindle. Of course, the sensor can also use a magnetic induction switch, etc. S3, Perform the returning-the-blade action; see below. Figure 2 and Figure 3 , S31. By cooperating with the spindle X-axis moving mechanism (not shown) and the tool magazine Y-axis moving mechanism (not shown) (i.e., the spindle fixing seat moves up and down under the drive of the Z-axis driving mechanism, and the spindle fixing seat moves horizontally on the X-axis fixing seat), the spindle 8 is moved above the tool holder 7, so that the spindle 8 is aligned with the empty position of the tool holder 7. S32. The Z-axis drive mechanism drives the spindle 8 to move downward, and the tool 6 on the spindle 8 moves downward to the set position, so that the tool holder 7 holds the positioning clamp 621 on the tool 6, and the spindle 8 stops moving downward; the spindle cylinder 81 inside the spindle 8 is inflated, the butterfly spring 83 is pressed down, the drive rod 84 moves downward, the locking mouth 85 opens, and the locking mouth 85 releases the upper part of the tool 6.

[0032] S33, the spindle 8 moves upward and disengages from the tool 6, completing the tool return.

[0033] S4. Perform the knife-grabbing action, and follow the steps below to grab the knife; such as Figures 4 to 7 As shown: S5. Through the cooperation of the spindle X-axis moving mechanism (not shown) and the tool magazine Y-axis moving mechanism (not shown), the spindle 8 is moved above the tool holder. The spindle 8 is aligned with the tool 6 pre-installed in the tool holder 7. The tool 6 has a blade 61 and a tool holder 62. The tool holder 62 includes a positioning clamp 621 with an axial through hole 6200 and a tensioning member 622. The upper end of the positioning clamp 621 is provided with a reference surface F. The clamping wall 621 of the positioning clamp 621... The positioning clamp 621 is provided with at least one upper opening groove 6211 and at least one lower opening groove 6212. The upper opening groove 6211 and the lower opening groove 6212 are staggered so that the positioning clamp 621 forms an elastic body. The tensioning member 622 is sleeved on the clamping wall 6210 of the positioning clamp 621. The positioning clamp 621 and the tensioning member 622 are coaxially arranged and used together to clamp the knife 61. The knife clamp sleeve 62 is coaxially positioned on the handle of the knife 61. S6 and Z-axis drive mechanisms drive the spindle 8 downwards, causing the reference surface H of the locking nozzle 85 inside the spindle 8 to contact the positioning surface F of the corresponding tool positioning clamp. Simultaneously, under the action of the spindle cylinder 81 built into the spindle 8, the drive rod 84 moves downwards, causing the locking nozzle 85 located at the lower end of the drive rod 84 to open. The upper part of the tool 6 extends into the locking nozzle 85, the spindle disc spring 83 located above the drive rod 84 is compressed, and the tool holder elastic body 72 inside the tool holder 7 is compressed under the downward force of the corresponding tool 6. Under the reaction force of the tool holder elastic body 72, the reference surface H of the locking nozzle 85 is brought into close contact with the positioning surface F of the positioning clamp 621 (e.g., ...). Figure 4 and Figure 5 As shown); in this embodiment, the tool holder elastic body 72 can be a tool holder spring, a tool holder elastic rubber, or a tool holder elastic air cushion, etc. (the same below).

[0034] S7. The spindle cylinder 81 is depressurized, the spindle disc spring 83 extends, driving the drive rod 84 to rise. The locking nozzle 85 follows the drive rod 84 to rise, and the locking nozzle 85 retracts to clamp the upper part of the tool 6, keeping the reference surface H of the locking nozzle 85 in close contact with the positioning surface F of the positioning clamp 621 (e.g., Figure 6 and Figure 7 As shown), the bore diameter D1 of the spindle 8 is larger than the outer diameter D2 of the positioning clamp 621. When the locking nozzle 85 rises, the tool 6 also rises, and the tool 61 and the positioning clamp 621 will also rise within the bore diameter D1 of the spindle 8.

[0035] The S8 and Z-axis drive devices drive the spindle to rise synchronously with the gripped tool, completing the tool change.

[0036] In this embodiment, preferably, step S5 further includes a tool assembly step: such as Figure 8 As shown: S51. Place the positioning clamp 621 in the special fixture 9. The upper end face of the positioning clamp 621 is provided with the F reference surface. The special fixture 9 has an upper reference surface and a lower reference surface. Ensure that the relative position of the F reference surface and the special fixture 9 is fixed, and ensure that the F reference surface and the upper reference surface of the special fixture 9 are aligned. The tool holder is inserted into the center hole 62100 of the positioning clamp 621, so that the E reference surface (i.e. the tool machining surface) of the bottom surface of the tool is aligned with the lower reference surface of the special fixture 9, and the relative distance between the E reference surface (i.e. the tool machining surface) of the bottom surface of the tool and the F reference surface reaches a predetermined distance. The tensioning member 622 is sleeved on the clamping wall 6219 of the positioning clamp 621, and the tensioning member 622 is moved upward. S52. Fix the positioning clip 621 onto the tool holder to form a cutting tool.

[0037] The core of this invention is as follows: First, when the Z-axis drive mechanism drives the spindle 8 downward, the reference surface H of the locking nozzle 85 inside the spindle 8 contacts the positioning surface F of the positioning clamp 621 of the corresponding tool 6. Second, the bore diameter D1 of the spindle 8 is larger than the outer diameter D2 of the positioning clamp 621. When the locking nozzle 85 rises, the tool 61 and the positioning clamp 621 also rise within the bore diameter D1 of the spindle 8. In this way, even if the locking nozzle 85 continues to pull upward, the reference surface H of the locking nozzle 85 and the positioning surface F of the positioning clamp 621 can still be in close contact. The positioning clamp 621 and the tool 61 can also move upward accordingly. The locking nozzle 85 will not move relative to the tool, and the position of the locking nozzle 85 holding the tool will not change. Thus, the position of the locking nozzle 85 holding the tool 6 will not move, the swing arm of the tool 6 will not change, and the tool 6 and the locking nozzle 85 can remain centered. In addition, the positioning clamp 621 in this invention is compact and small, and is less prone to shaking in high-speed machine tools, resulting in better stability.

[0038] In this invention, preferably, step S9 is also included, and steps S2-S8 are repeated, thereby realizing the cyclic tool changing function in the machining process.

[0039] The present invention also provides a knife clip (such as...) Figures 9 to 14As shown, a tool holder includes a positioning clamp 621 with an axial through hole 62100 and a tensioning member 622. The upper end of the positioning clamp 621 is provided with a reference surface F. The clamping wall 6210 of the positioning clamp 621 is provided with at least one upper opening groove 6211 and at least one lower opening groove 6212. The upper opening groove 6211 and the lower opening groove 6212 are staggered so that the positioning clamp 621 forms an elastic body. The tensioning member 622 is sleeved on the clamping wall 6210 of the positioning clamp 621. The positioning clamp 621 and the tensioning member 622 are coaxially arranged and used together to clamp the tool 61. In this embodiment, preferably, the tensioning member 622 is a tensioning nut, the lower middle part of the clamping wall 6210 of the positioning clamp 621 is provided with an external thread 62160, the tensioning nut is sleeved on the clamping wall 6210 of the positioning clamp 621, the tensioning nut is provided with an internal thread that matches the external thread 62160, the positioning clamp 621 and the tensioning nut 622 are coaxially arranged and used together to clamp the blade 61.

[0040] In use, the positioning clamp 621 is first fixed. Specifically, the positioning clamp 621 is placed in the special fixture 90. Since the upper end face of the positioning clamp 621 has an F reference surface, the relative position of the B reference surface and the special fixture 90 is fixed, thus eliminating the need for tool setting 61. Moreover, the relative position remains unchanged during subsequent repeated clamping. Then, the tool 61 is axially placed in the through hole 62100 of the fixed positioning clamp 621, so that the relative distance between the E reference surface and the F reference surface on the bottom surface of the tool 61 reaches a predetermined distance (in this invention). The predetermined distance can be set according to actual usage requirements (this invention does not impose any limitations). Then, the tension nut 622 is fitted onto the clamping wall 6210 of the positioning clamp 621, and the tension nut is screwed upward. The tension nut moves upward along the clamping wall 6210, thereby causing the tension nut to move upward. Since the positioning clamp 621 is an elastic body with two upper opening grooves 6211 and two lower opening grooves 6212, the upward push of the tension nut will push the positioning clamp 621 to retract until the inner wall of the positioning clamp 621 completely clamps the blade 6. On the outer wall surface of 1, in this invention, due to the misalignment of the upper opening groove 6211 and the lower opening groove 6212, the positioning clamp 621 can retract or open radially in a completely equal manner, allowing the tool 61 to smoothly enter the positioning clamp 621 while its center of gravity remains at the axis center. The inward movement of the positioning clamp 621 is always equal in the radial direction of the tool 61. The F reference plane of the locked positioning clamp 621 maintains a high degree of perpendicularity with the axis A reference of the tool 61. Thus, even during high-speed operation, the tool holder will not shake or... The loosening phenomenon ensures a very firm grip on the tool 61, so that not only does the F reference plane always remain horizontal, but the tool 61 will also not wobble or shift. As a result, the distance between the F reference plane and the E reference plane can always remain consistent. Even with repeated clamping, the distance between the F reference plane and the E reference plane can be kept basically consistent each time, thus ensuring the accuracy of repeated clamping and machining. In addition, in this invention, the tool holder consists of fewer parts, including the positioning clamp 621 and the tensioning member 622, making the structure simpler and the disassembly and assembly more convenient.

[0041] In this invention, preferably, the upper opening groove 6211 extends downward from the upper end face 6213 of the positioning clamp to near the lower end face 6214 of the positioning clamp, and the lower opening groove 6212 extends upward from the lower end face 6214 of the positioning clamp to near the upper end face 6213 of the positioning clamp. In addition, the upper opening groove 6211 and the lower opening groove 6212 are staggered to ensure that the positioning clamp 621 can retract or open radially in an equal amount.

[0042] In this invention, preferably, the positioning clamp 621 includes a clamp cap portion 6215 and a clamp body portion 6216. The outer diameter of the clamp body portion 6216 gradually increases from bottom to top to form a conical surface. The inner wall 6222 of the tensioning nut is a conical inner wall that matches the conical surface of the clamp body portion 6216. The advantage of this design is that the conical surface of the clamp body portion 6216 matches the conical inner wall of the tensioning nut. During the upward pushing of the tensioning nut, the outer surface of the clamp body portion 6216 can be pressed tightly, and the positioning clamp 621 retracts inward to hold the knife 61, thereby improving the fixing effect of the knife clamp sleeve of this invention.

[0043] In this invention, preferably, the clamp cap 6215 is a convex ring structure, and the outer diameter of the clamp cap 6215 is larger than the outer diameter of the clamp body 6216. Specifically, in this invention, the clamp cap 6215 and the clamp body 6216 are integrally formed.

[0044] In this invention, preferably, the positioning clamp 621 is made of manganese-titanium quenched steel. The advantage of using manganese-titanium quenched steel is that it can ensure that the positioning clamp 621 has good elasticity. In addition, in this invention, in order to ensure that the center of gravity of the tool holder itself matches the axis, the positioning clamp 621 and the tensioning nut are all machined by high-precision CNC lathe, while the outer wall 6210 of the positioning clamp 621 is precision machined by precision slow wire cutting.

[0045] In this invention, preferably, the outer wall of the tensioning nut is provided with at least two grooves 6223, and the at least two grooves 6223 are arranged around the outer wall of the tensioning nut at a predetermined distance. In this embodiment, there are four grooves 6223. The function of the grooves 6223 is to prevent slippage, so that the tensioning nut can increase the friction when rotating, and the tightening effect is better.

[0046] The above description is only a preferred embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any equivalent substitutions or modifications made by those skilled in the art within the scope of the technology disclosed in the present invention, based on the technical solution and inventive concept of the present invention, should be covered within the scope of protection of the present invention.

Claims

1. A method for automatic tool changing in high-precision machining using a high-speed CNC spindle, characterized in that: Includes the following steps: S1. Send tool change command; S2. The sensor detects whether there is a tool on the spindle. If there is, proceed to step S3; otherwise, proceed to step S4. S3. Perform the knife return action; S4. Perform the knife-grabbing action, and grasp the knife according to the following steps; S5. Move the spindle above the tool holder and align the spindle with the tool pre-installed in the tool holder. The tool has a blade and a tool holder. The tool holder includes a positioning clamp (621) with an axial through hole (62100) and a tensioning member (622). The upper end of the positioning clamp (621) is provided with a reference surface F. The clamping wall (6210) of the positioning clamp (621) is provided with at least one upper opening groove (6211) and at least one lower opening groove (6212). The upper opening groove (6211) and the lower opening groove (6212) are misaligned so that the positioning clamp (621) forms an elastic body. The tensioning member (622) is sleeved outside the clamping wall (6210) of the positioning clamp (621). The positioning clamp (621) and the tensioning member (622) are coaxially arranged and used together to clamp the tool (61). The tool holder (62) is coaxially positioned on the handle of the tool (61). S6, the Z-axis drive mechanism drives the spindle to move downward, so that the reference surface H of the locking nozzle inside the spindle contacts the positioning surface F of the corresponding tool positioning clamp. At the same time, under the action of the spindle cylinder built into the spindle, the drive rod moves downward, so that the locking nozzle located at the lower end of the drive rod opens, the upper part of the tool extends into the locking nozzle, the spindle disc spring located at the upper part of the drive rod is compressed, and the tool holder elastic body inside the tool holder is compressed under the action of the downward force of the corresponding tool. Under the action of the reaction force of the tool holder elastic body, the reference surface of the locking nozzle is in close contact with the positioning surface of the positioning clamp. S7. The spindle cylinder is depressurized, the spindle disc spring extends and drives the drive rod to rise, the locking nozzle follows the drive rod to rise, the locking nozzle retracts and clamps the upper part of the tool, keeping the reference surface H of the locking nozzle and the positioning surface F of the positioning clamp in close contact. The bore diameter D1 of the spindle is larger than the outer diameter D2 of the positioning clamp. When the locking nozzle rises, the positioning clamp and the tool can also rise within the bore diameter D1. S8 and Z-axis drive devices drive the spindle to rise synchronously with the gripped tool, completing the tool change; Step S5 also includes a tool assembly step: S51. Place the positioning clamp in the special fixture. The upper end face of the positioning clamp is provided with the F reference surface to ensure that the relative position of the F reference surface and the special fixture is fixed. The tool holder is inserted into the center hole of the positioning clamp so that the relative distance between the E reference surface of the bottom surface of the tool and the F reference surface reaches a predetermined distance. The tensioning member is sleeved on the clamp wall of the positioning clamp and the tensioning member is moved upward. S52. Fix the positioning clamp to the tool holder to form the cutting tool.

2. The automatic tool changing method for high-precision machining using a high-speed CNC spindle according to claim 1, characterized in that: It also includes step S9 and repeating steps S2-S8 to achieve the cyclic tool changing function during the machining process.

3. The automatic tool changing method for high-precision machining with a high-speed CNC spindle according to claim 2, characterized in that: Step S3 includes the following steps: S31. Move the spindle above the tool holder so that the spindle is aligned with the empty space in the tool holder; S32. The Z-axis drive mechanism drives the spindle to move downward, and the tool on the spindle moves downward to a set position, so that the tool holder holds the positioning clamp on the tool, and the spindle stops moving downward; the spindle cylinder inside the spindle is inflated, the disc spring is pressed down, the drive rod moves downward, the locking mouth opens, and the locking mouth releases the upper part of the tool; S33, the spindle moves upward and disengages from the tool, completing the tool return.

4. A tool holder, used in the automatic tool changing method for high-precision machining of high-speed CNC spindles as described in any one of claims 1-3, characterized in that: The device includes a positioning clamp (621) with an axial through hole (62100) and a tensioner (622). The upper end of the positioning clamp (621) is provided with a reference surface F. The clamping wall (6210) of the positioning clamp (621) is provided with at least one upper opening groove (6211) and at least one lower opening groove (6212). The upper opening groove (6211) and the lower opening groove (6212) are misaligned so that the positioning clamp (621) forms an elastic body. The tensioner (622) is sleeved on the clamping wall (6210) of the positioning clamp (621). The positioning clamp (621) and the tensioner (622) are coaxially arranged and used together to clamp the tool (61).

5. The tool holder according to claim 4, characterized in that: The tensioning element (622) is a tensioning nut. The lower middle part of the clamping wall (6210) of the positioning clamp (621) is provided with an external thread (62160). The tensioning nut is sleeved on the outside of the clamping wall (6210) of the positioning clamp (621). The tensioning nut is provided with an internal thread that matches the external thread (62160). The positioning clamp (621) and the tensioning nut are coaxially arranged and used together to clamp the blade (61).

6. The tool holder according to claim 4, characterized in that: The upper opening groove (6211) extends downward from the upper end face (6213) of the positioning clamp to near the lower end face (6214) of the positioning clamp, and the lower opening groove (6212) extends upward from the lower end face (6214) of the positioning clamp to near the upper end face (6213) of the positioning clamp.

7. The tool holder according to claim 5, characterized in that: The positioning clamp (621) includes a clamp cap (6215) and a clamp body (6216), the outer diameter of which gradually increases from bottom to top to form a conical surface.

8. The tool holder according to claim 7, characterized in that: The inner wall (6222) of the tensioning nut is a tapered inner wall that matches the tapered surface of the clamping part (6216).

9. The tool holder according to claim 7, characterized in that: The cap portion (6215) has a convex ring structure, and the outer diameter of the cap portion (6215) is larger than the outer diameter of the body portion (6216).

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