A milling device and method for milling the interior cavity of a profile

Abstract

This invention discloses a milling device and method for milling the inner cavity of a profile, belonging to the field of mechanical processing and manufacturing technology. The device includes: an internally supported right-angle milling device comprising a long overhanging drive shaft, a right-angle milling head, an integrated retractable fluid-driven support mechanism, and a high-pressure internal cooling channel; maintaining the support mechanism contracted, extending the milling head axially into the inner cavity of the profile to a preset depth to ensure its smooth passage through the restricted section; driving the support mechanism to expand radially and press against the inner wall, realizing the transformation from a cantilever beam to a multi-point support beam mechanical model, thereby significantly improving system stiffness and suppressing chatter; performing cutting under this high-rigidity state, while continuously injecting high-pressure fluid through the channel, using fluid kinetic energy to force the chips out of the cavity. This invention significantly improves the equivalent stiffness of the cutting system, suppresses cutting chatter caused by excessive overhang, and thus greatly improves the surface finish and dimensional accuracy of the processed inner cavity of the profile.

Description

Technical Field

[0001] This invention relates to the field of machining and manufacturing, specifically to a milling device and method for milling the internal cavity of a profile. Background Technology

[0002] Currently, the main technology for machining the internal cavity of profiles involves using a long overhanging tool to extend into the deep cavity for construction. The power source is transmitted to the end tool through a slender drive shaft. During the axial feed process, the rotating cutting edge is used to remove material to achieve the forming of the closed cavity structure. In conventional scenarios, such devices are regarded as cantilever beam models, relying on a single overhanging structure to support the cutting load.

[0003] However, in related technologies, with the increase in the depth-to-diameter ratio of the profile cavity and the improvement in the requirements for the form and position tolerances of the machined surface, the machining mode based on traditional long overhanging tools will bring some problems or weaknesses. For example, the extremely low stiffness of the free end leads to large deflection and severe chatter during the cutting process, making it difficult to guarantee machining accuracy and surface finish; the traditional straight shank structure is difficult to effectively reach and mill the inner cavity sidewalls; and in the narrow and enclosed space, chips are difficult to be discharged and accumulate, and the accompanying heat accumulation is prone to workpiece thermal deformation or cause the motion mechanism to fail due to jamming, resulting in poor machining stability, which urgently needs improvement; therefore, a solution is urgently needed to solve the problems existing in the current technology.

[0004] The information disclosed in the background section is only intended to enhance the understanding of the background of this disclosure and therefore does not constitute information about prior art known to those skilled in the art. Summary of the Invention

[0005] The purpose of this invention is to provide a milling apparatus and method for milling the internal cavity of profiles, so as to solve the problems mentioned in the background art. The technical solution of this invention includes:

[0006] S1. An internally supported right-angle milling device is provided, wherein the internally supported right-angle milling device includes a long overhanging drive shaft and a right-angle milling head connected to its end. A retractable fluid-driven support mechanism is integrated on the non-cutting side wall of the right-angle milling head, and a high-pressure internal cooling chip-removing channel is provided through the inside of the long overhanging drive shaft.

[0007] S2. The right-angle milling head is inserted axially into the profile cavity to a preset machining depth, while keeping the retractable fluid-driven support mechanism in a retracted state so that the right-angle milling head passes through the restricted section of the profile cavity.

[0008] S3. Perform multi-point support rigid conversion. Drive the retractable fluid drive support mechanism to expand radially outward through hydraulic or pneumatic means until the support end face of the retractable fluid drive support mechanism abuts against the inner wall of the profile cavity. Transform the mechanical model of the long cantilever drive shaft from a cantilever beam structure to a multi-point support beam structure to improve the equivalent stiffness of the cutting system and suppress cutting chatter.

[0009] S4. Perform sidewall milling and chip removal under high rigidity conditions, drive the right-angle milling head to perform cutting operations, and continuously spray high-pressure fluid into the processing area through the high-pressure internal cooling chip removal channel, using the fluid recoil force and kinetic energy in the enclosed space to force the chips out of the profile cavity.

[0010] Optionally, step S3 further includes:

[0011] The vibration amplitude of the right-angle milling head is monitored in real time, and the output pressure of the stretchable fluid drive support mechanism is dynamically adjusted according to the change of the vibration amplitude. When the vibration amplitude exceeds a preset threshold, the output pressure is increased to improve the system damping ratio until the vibration amplitude falls back to the stable cutting range.

[0012] Optionally, step S4 includes:

[0013] S4.1 Set the fluid outlet pressure and flow rate of the high-pressure internal cooling chip-removing channel so that it forms an annular wrapping flow field with a preset flow velocity around the right-angle milling head;

[0014] S4.2 The annular wrapping flow field is used to exchange and cool the high temperature generated by cutting, and the directional flow characteristics of the flow field are used to prevent the chips from accumulating at the expansion gap of the expandable fluid-driven support mechanism.

[0015] Optionally, after step S3 and before performing axial feed cutting, the method further includes:

[0016] The contact pressure between the retractable fluid-driven support mechanism and the inner wall of the profile cavity is detected, and it is confirmed that the contact pressure reaches a preset locking value to prevent displacement and slippage under the action of cutting reaction force.

[0017] A milling apparatus for milling the inner cavity of a profile includes:

[0018] The long overhang transmission assembly includes a long overhang transmission shaft with an outer diameter smaller than the cross-section of the inner cavity of a preset profile and a right-angle milling head located at the end of the shaft;

[0019] The internally supported shock absorption assembly has a high-pressure internally cooled chip-bursting channel that is connected to an external fluid source through a rotary joint located at the input end of the long overhanging drive shaft, and the retractable fluid-driven support mechanism can generate radial displacement relative to the right-angle milling head under fluid pressure.

[0020] The fluid circulation assembly includes a high-pressure internal cooling chip-removing channel that runs through the long overhanging drive shaft, the outlet of which points towards the cutting edge region.

[0021] Optionally, the retractable fluid-driven support mechanism includes:

[0022] An embedded fluid-driven cylinder is disposed inside the housing of the right-angle milling head;

[0023] The contoured support shoe is connected to the piston rod end of the embedded fluid drive cylinder. The outer surface curvature of the contoured support shoe matches the inner wall curvature of the profile cavity, which is used to increase the contact area and disperse the support stress.

[0024] Optionally, the length-to-diameter ratio of the long overhang drive shaft is greater than 3:1, and the high-pressure internal cooling chip-removing channel is a hollow sandwich structure coaxially arranged inside the long overhang drive shaft.

[0025] Optionally, the surface of the conformal support shoe is coated with a wear-resistant damping coating to provide additional frictional resistance and absorb high-frequency vibration energy when in contact with the inner wall of the profile cavity.

[0026] Optionally, the device further includes a pressure adaptive control unit integrated into the main control system, which is connected to the retractable fluid-driven support mechanism and is used to automatically maintain a constant support pressure according to the cutting conditions.

[0027] This invention provides a milling apparatus and method for milling the internal cavity of a profile, which has the following improvements and advantages compared with the prior art:

[0028] 1. This invention innovatively solves the problem of insufficient rigidity of long overhanging tools in deep cavity machining by integrating a retractable fluid-driven support mechanism into the side wall of the right-angle milling head. During cutting, the support mechanism expands radially and presses against the inner wall of the profile cavity, transforming the mechanical model of the long overhanging drive shaft from a highly deformable cantilever beam structure into a multi-point support beam structure with forces at both ends or multiple points. This structural rigidity transformation significantly improves the equivalent stiffness of the cutting system, fundamentally suppressing cutting chatter caused by excessive overhang, thereby greatly improving the surface finish and dimensional accuracy of the profile cavity machining surface.

[0029] 2. This invention utilizes a high-pressure internal cooling chip-removing channel that runs through the drive shaft to construct a highly efficient fluid circulation system for enclosed deep hole environments. By forming an annular enveloping flow field with a specific flow velocity around the milling head, the device can use the kinetic energy and recoil force of the high-pressure fluid to force the chips out of the narrow profile cavity, completely solving the common chip accumulation and clogging problem in deep hole machining. At the same time, the directional flow characteristics of the flow field not only provide efficient heat exchange and cooling for the cutting area, but also form a fluid barrier to effectively prevent small chips from getting stuck in the expansion gaps of the support mechanism, ensuring the long-term reliability of the device.

[0030] 3. This invention possesses intelligent cutting state sensing and adjustment capabilities, enabling dynamic optimization of support force through real-time monitoring of the milling head's vibration amplitude. When vibration exceeds the limit during machining, the system automatically increases the output pressure of the hydraulic or pneumatic support mechanism, thereby rapidly increasing the system's damping ratio and bringing the vibration amplitude back to the stable cutting range. Combined with the wear-resistant damping coating on the surface of the contoured support shoes, the device provides stable support friction while also absorbing high-frequency vibration energy. This combination of active adjustment and passive energy absorption significantly extends tool life and adapts to complex working conditions with large variations in cutting allowance.

[0031] 4. This invention employs a small outer diameter and long overhang design, combined with a right-angle milling head at the end, and a matching structure of contoured support shoes, greatly expanding the processing range. In its retracted state, the device can smoothly pass through the confined cross-section of the profile's inner cavity and penetrate deep into areas with a length-to-diameter ratio greater than 3:1. The curvature of the outer surface of the contoured shoes precisely matches the inner wall of the cavity, which not only increases the contact area to ensure stable support but also evenly disperses the support stress, preventing damage to the workpiece's inner wall due to excessive local pressure. This design achieves highly stable operation in extremely confined spaces, meeting the precision milling requirements of complex cross-section profiles. Attached Figure Description

[0032] The present invention will be further explained below with reference to the accompanying drawings and embodiments:

[0033] Figure 1 This is a schematic diagram of the overall structure of the device;

[0034] Figure 2 This is a schematic diagram of the structure of the right-angle milling head and the fluid circulation assembly;

[0035] Figure 3 This is a structural schematic diagram of an internally supported damping component;

[0036] Figure 4 This is a schematic diagram of the process flow of the method of the present invention.

[0037] In the diagram: 100, long overhang transmission assembly; 110, long overhang transmission shaft; 120, right-angle milling head; 200, internal support damping assembly; 210, retractable fluid drive support mechanism; 211, embedded fluid drive cylinder; 212, contour support shoe; 300, fluid circulation assembly; 310, high-pressure internal cooling chip removal channel; 400, pressure adaptive control unit. Detailed Implementation

[0038] To make the objectives, technical solutions, and advantages of this invention clearer, the invention will be further described in detail below with reference to specific embodiments.

[0039] Example 1:

[0040] Please see Figure 1-4 A milling method for milling the inner cavity of a profile, comprising:

[0041] S1. An internally supported right-angle milling device is provided, wherein the internally supported right-angle milling device includes a long overhanging drive shaft 110 and a right-angle milling head 120 connected to its end. A retractable fluid-driven support mechanism 210 is integrated on the non-cutting side wall of the right-angle milling head 120. A high-pressure internal cooling chip-removing channel 310 is provided inside the long overhanging drive shaft 110.

[0042] S2. The right-angle milling head 120 is inserted axially into the profile cavity to a preset machining depth, while keeping the retractable fluid-driven support mechanism 210 in a retracted state so that the right-angle milling head 120 passes through the restricted section of the profile cavity.

[0043] S3. Perform multi-point support rigid conversion. Drive the retractable fluid drive support mechanism 210 radially outward by hydraulic or pneumatic means until the support end face of the retractable fluid drive support mechanism 210 presses against the inner wall of the profile cavity. Transform the mechanical model of the long cantilever drive shaft 110 from a cantilever beam structure to a multi-point support beam structure to improve the equivalent stiffness of the cutting system and suppress cutting chatter.

[0044] S4. Perform sidewall milling and chip removal under high rigidity conditions, drive the right-angle milling head 120 to perform cutting operations, and at the same time continuously spray high-pressure fluid into the processing area through the high-pressure internal cooling chip removal channel 310, using the fluid recoil force and kinetic energy in the enclosed space to force the chips out of the profile cavity.

[0045] In this embodiment, a milling method based on the principle of rigidity conversion is proposed to address the pain points of existing profile internal cavity machining technology, which relies on long overhanging tools, resulting in insufficient rigidity, severe chatter, and inability to effectively reach the internal cavity sidewalls.

[0046] In step S1, the internally supported right-angle milling device is configured as the core execution unit; the long overhanging drive shaft 110 is responsible for transmitting external power to the deep cavity, and its length is usually greater than 300mm to meet the needs of deep cavity machining; the right-angle milling head 120 deflects the axis of rotational power by 90 degrees, thereby realizing the cutting of the inner cavity sidewall of the profile, solving the problem that straight shank tools cannot machine the inner cavity sidewall; the retractable fluid-driven support mechanism 210 is integrated into the back of the milling head as a key component for active vibration reduction; the high-pressure internal cooling chip removal channel 310 is to solve the problem of chip accumulation in the enclosed space causing damage to the transmission components;

[0047] In step S2, keeping the retractable fluid-driven support mechanism 210 in the retracted state is a prerequisite for entering the profile cavity. Since the cross-sectional dimensions of the profile cavity are limited, for example, less than 50mm, the retracted state ensures that the overall outer contour of the device is smaller than the minimum aperture of the cavity channel, so that the right-angle milling head 120 can be fed axially to the preset machining depth without obstruction.

[0048] In step S3, the core innovation of this invention is the implementation of multi-point support rigidity conversion. In conventional technology, long overhanging cutters are regarded as cantilever beam models, with extremely low stiffness at their free ends, making them prone to deflection and vibration. In this step, the controller drives a hydraulic or pneumatic source to make the stretchable fluid drive support mechanism 210 extend radially until its support end face forms an interference or compression contact with the inner wall of the profile cavity.

[0049] At this point, a stable fulcrum is added to the end of the long cantilever drive shaft 110, i.e. the milling head position. The mechanical model instantly changes from an unstable cantilever beam to a high-rigidity simply supported beam or multi-point supported beam structure. This structural change improves the equivalent stiffness of the cutting system and suppresses the generation of cutting chatter.

[0050] In step S4, sidewall milling and chip removal are performed simultaneously. Since the system is already in a high-rigidity state, the right-angle milling head 120 can use larger cutting parameters for efficient operation. At the same time, the high-pressure internal cooling chip removal channel 310 continues to work, and high-pressure fluid, i.e., cutting fluid or compressed air, is directly sprayed into the cutting area. In the narrow profile cavity, the fluid cannot escape in all directions and can only flow outward at high speed along the cavity. The fluid recoil force and kinetic energy in this confined space are used to force the chips out and prevent the chips from accumulating in the cavity.

[0051] Step S3 also includes: real-time monitoring of the vibration amplitude of the right-angle milling head 120, dynamically adjusting the output pressure of the stretchable fluid drive support mechanism 210 according to the change of vibration amplitude, and increasing the output pressure to improve the system damping ratio when the vibration amplitude exceeds the preset threshold, until the vibration amplitude falls back to the stable cutting range.

[0052] In this embodiment, step S3 introduces active vibration suppression control logic; although structural transformation improves static stiffness, dynamic instability may still be induced during the cutting process due to factors such as uneven material or intermittent cutting; by setting a vibration sensor at or near the right-angle milling head 120, the vibration amplitude during the machining process is monitored in real time; the controller compares the monitored value with a preset safety threshold.

[0053] Once the vibration amplitude is detected to be exceeding the threshold, it is determined that there is a risk of chatter. The system immediately commands an increase in the fluid pressure of the stretchable fluid drive support mechanism 210. The increased pressure not only improves the contact stiffness, but also increases the damping ratio of the system by increasing the friction between the contact surfaces, thereby quickly absorbing vibration energy and suppressing the vibration amplitude back to the stable cutting range, realizing intelligent adaptive machining.

[0054] The steps in S4 include:

[0055] S4.1 Set the fluid outlet pressure and flow rate of the high-pressure internal cooling chip-removing channel 310 so that it forms an annular wrapping flow field with a preset flow velocity around the right-angle milling head 120.

[0056] S4.2 The annular wrapping flow field is used to exchange and cool the high temperature generated by cutting, and the directional flow characteristics of the flow field are used to prevent chips from accumulating in the expansion gap of the expandable fluid-driven support mechanism 210.

[0057] In this embodiment, the fluid control strategy is further refined to address the issues of heat accumulation and mechanism jamming;

[0058] In step S4.1, the outlet pressure and flow rate of the high-pressure internal cooling chip-removing channel 310 are set by accurately calculating the difference between the cross-sectional area of ​​the profile cavity and the area occupied by the device:

[0059] The specific steps for precise calculation are: the minimum suspension velocity of the chips in the fluid. This speed value must meet the following requirements. ,in The equivalent diameter of the chip. For chip density, For fluid density, This is the drag coefficient, typically taken as a value for metal chips. ;

[0060] Based on the cross-sectional area of ​​the profile's inner cavity Area occupied by the device Calculate the flow area of ​​the annular gap ;

[0061] Set the output flow rate of the high-pressure internal cooling chip removal channel 310 The flow conservation formula must be satisfied:

[0062]

[0063] in, This is the flow resistance compensation coefficient, and its value range is... This ensures that the local flow velocity at irregular cross-sections is always greater than the settling velocity of the chips, thereby forming an effective annular wrapping flow field.

[0064] This allows the fluid to fill the gap between the milling head and the inner cavity wall, forming a ring-shaped enveloping flow field that flows outward at high speed along the axial direction;

[0065] In step S4.2, the annular wrapping flow field plays a dual role: it directly scours the cutting zone, rapidly removing cutting heat through heat exchange to prevent workpiece thermal deformation and tool overheating and wear; utilizing the boundary layer effect and directional flow characteristics of fluid mechanics, the flow field forms a scouring protective layer when passing through the expandable fluid-driven support mechanism 210, preventing small chips from intruding into the expansion gaps or mating surfaces of the support mechanism, avoiding mechanism failure or movement jamming caused by chip jamming, and ensuring the reliability of the support action.

[0066] After step S3, before performing axial feed cutting, the following steps are also included: detecting the contact pressure between the retractable fluid-driven support mechanism 210 and the inner wall of the profile cavity, and confirming that the contact pressure reaches the preset locking value to prevent displacement and slippage under the action of cutting reaction force.

[0067] In this embodiment, to ensure machining accuracy and safety, a status confirmation step is added; before the right-angle milling head 120 starts rotating and cutting, the contact pressure of the support part is detected by a pressure sensor; only when the contact pressure reaches the preset locking value will the controller allow the execution of subsequent cutting commands.

[0068] Preset lock value The calculation is based on the following:

[0069] Obtain the maximum axial feed resistance under the current machining process. and the tangential component caused by the cutting torque Total combined cutting reaction force:

[0070]

[0071] Let the coefficient of static friction between the conformal support shoe 212 and the inner wall of the profile cavity be... Considering the wear-resistant damping coating, this value is usually taken as... The effective contact area is Set the safety factor to and ;

[0072] The minimum locking pressure at which the controller allows the feed action to be performed. The following inequalities must be satisfied:

[0073]

[0074] This formula ensures the static friction resistance generated by the support mechanism. It is always greater than the maximum destructive force during the cutting process, thus ensuring the absolute position locking of the device at the physical level;

[0075] This value is calculated based on the maximum cutting force to ensure that the controller allows subsequent feed actions only when the static friction force is greater than the axial cutting force. This logical interlocking mechanism prevents the entire device from undergoing axial displacement or vibration slippage in the inner cavity due to insufficient support force under the action of cutting reaction force, thereby ensuring the accuracy of the machining position and the stability of the device.

[0076] Example 2:

[0077] Please see Figure 1-3 A milling apparatus for milling the inner cavity of a profile, comprising:

[0078] The long overhang transmission assembly 100 includes a long overhang transmission shaft 110 with an outer diameter smaller than the cross-section of the inner cavity of a preset profile and a right-angle milling head 120 located at the end of the shaft.

[0079] The internal support damping assembly 200 includes a retractable fluid-driven support mechanism 210 integrated into the sidewall of the right-angle milling head 120. The retractable fluid-driven support mechanism 210 is capable of generating radial displacement relative to the right-angle milling head 120 under fluid pressure.

[0080] The fluid circulation assembly 300 and the high-pressure internal cooling chip removal channel 310 are connected to an external fluid source through a rotary joint located at the input end of the long overhanging drive shaft 110, and the outlet of the high-pressure internal cooling chip removal channel 310 points to the cutting edge area.

[0081] In this embodiment, the hardware device structure for implementing the above method is described in detail;

[0082] The long overhang transmission assembly 100 is the main skeleton of the device; the long overhang transmission shaft 110 is designed as a slender rod, and its outer diameter is strictly controlled within the minimum cross section of the preset profile cavity; the right angle milling head 120 is located at the shaft end and contains a precision gear transmission assembly, which is used to convert the longitudinal rotation of the transmission shaft into the transverse rotation of the milling cutter, thereby enabling the processing of the side wall.

[0083] The internally supported shock absorber 200 is the core feature of the device; the retractable fluid-driven support mechanism 210 is not a simple passive pad, but an active actuator; it is integrated into the side wall of the milling head and drives the support component to make radial extension and retraction relative to the milling head body through the change of pressure in the internal fluid chamber; this design allows the device to switch freely between pass mode, i.e., contraction mode and machining mode, i.e., expansion support.

[0084] The fluid circulation component 300 solves the problem of chip removal in deep cavities; the high-pressure internal cooling chip flushing channel 310 runs through the entire drive shaft in physical structure, and its outlet is optimized to precisely point to the cutting edge area, ensuring that the coolant can contact the high-temperature chips as soon as possible and provide the maximum flushing kinetic energy.

[0085] The retractable fluid-driven support mechanism 210 includes: an embedded fluid-driven cylinder 211, which is disposed inside the housing of the right-angle milling head 120; and a contoured support shoe 212, which is connected to the piston rod end of the embedded fluid-driven cylinder 211. The curvature of the outer surface of the contoured support shoe 212 matches the curvature of the inner wall of the profile cavity, in order to increase the contact area and disperse the support stress.

[0086] In this embodiment, the structure of the support mechanism is described in detail; the embedded fluid drive cylinder 211 is the source of power, and it is compactly designed within the limited housing space of the right-angle milling head 120, and can be a miniature hydraulic cylinder or a pneumatic cylinder.

[0087] To address the issues of point contact easily damaging the inner wall of the workpiece and insufficient support stiffness, this embodiment employs a contoured support shoe 212. This shoe is connected to the end of the piston rod, and its outer surface geometry is specifically customized or matched to the inner wall geometry of the profile to be processed. When the support action occurs, the contoured support shoe 212 forms surface contact with the inner wall instead of line or point contact. This design greatly increases the effective contact area, significantly improving support stiffness and distributing the enormous support force over a larger area, reducing the contact stress per unit area, and preventing excessive support force from causing local deformation or surface indentation in the thin-walled profile.

[0088] The length-to-diameter ratio of the long overhang drive shaft 110 is greater than 3:1, and the high-pressure internal cooling chip removal channel 310 is a hollow sandwich structure coaxially arranged inside the long overhang drive shaft 110.

[0089] In this embodiment, the deep cavity machining attributes and structural layout of the device are clearly defined; the setting that the length-to-diameter ratio of the long overhanging drive shaft 110 is greater than 3:1 clearly defines that the device is designed for deep hole or deep cavity machining scenarios, which is also the area where rigidity problems are most prominent in traditional machining.

[0090] In order to achieve functional integration within a limited shaft diameter, the high-pressure internal cooling chip removal channel 310 adopts a hollow sandwich structure design; that is, the drive shaft itself is designed as a hollow tube, or the liquid delivery pipe is arranged coaxially in the central hole of the drive shaft. This coaxial layout not only maximizes the use of cross-sectional space, but also makes the flow direction of the coolant coincide with the rotation axis of the drive shaft, reducing the interference of centrifugal force during rotation and ensuring the stability of fluid transmission.

[0091] The surface of the conformal support shoe 212 is coated with a wear-resistant damping coating to provide additional frictional resistance and absorb high-frequency vibration energy when in contact with the inner wall of the profile cavity.

[0092] In this embodiment, the surface properties of the conformal support shoe 212 are functionally enhanced; a special wear-resistant damping coating, such as polyurethane, hard rubber or special composite material, is applied to the metal substrate surface of the shoe.

[0093] This coating has two key functions:

[0094] It typically has a higher coefficient of friction than metals, and can provide greater static friction under the same normal pressure, thus more effectively preventing the device from slipping or shifting under cutting force;

[0095] Polymer materials have excellent damping properties, which can absorb the high-frequency vibration energy generated during the cutting process, cut off the transmission path of vibration waves to the support mechanism and transmission shaft, and further improve the surface finish of the machined surface.

[0096] The device also includes a pressure adaptive control unit 400 integrated into the main control system, which is connected to the retractable fluid-driven support mechanism 210 to automatically maintain a constant support pressure according to the cutting conditions.

[0097] In this embodiment, a pressure adaptive control unit 400 is introduced to cope with complex working conditions. In actual processing, the hydraulic or pneumatic system may experience pressure drop due to leakage, temperature changes, or external load fluctuations. The pressure adaptive control unit 400, including pressure sensors, accumulators, and proportional valves, monitors the pressure inside the drive cylinder in real time. Once a pressure fluctuation is detected to deviate from the set value, the control unit will automatically perform pressure replenishment or pressure relief operations to maintain a constant support pressure. This ensures that the support stiffness provided by the internal support damping component 200 remains consistent throughout the entire long processing cycle, regardless of how the cutting load fluctuates, thus guaranteeing the consistency of processing quality.

[0098] It should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and are not intended to limit it. Although the present invention has been described in detail with reference to preferred embodiments, those skilled in the art should understand that modifications or equivalent substitutions can be made to the technical solutions of the present invention without departing from the spirit and scope of the technical solutions of the present invention.

Claims

1. A milling method for milling the inner cavity of a profile, characterized in that, include: S1. An internally supported right-angle milling device is provided, wherein the internally supported right-angle milling device includes a long overhanging drive shaft (110) and a right-angle milling head (120) connected to its end. A retractable fluid-driven support mechanism (210) is integrated on the non-cutting side wall of the right-angle milling head (120). A high-pressure internal cooling chip-removing channel (310) is provided inside the long overhanging drive shaft (110). S2. The right-angle milling head (120) is inserted axially into the profile cavity to a preset processing depth, while keeping the retractable fluid-driven support mechanism (210) in a retracted state so that the right-angle milling head (120) passes through the restricted section of the profile cavity. S3. Perform multi-point support rigid conversion, drive the retractable fluid drive support mechanism (210) to expand radially outward by hydraulic or pneumatic means until the support end face of the retractable fluid drive support mechanism (210) abuts against the inner wall of the profile cavity, and transform the mechanical model of the long cantilever transmission shaft (110) from a cantilever beam structure to a multi-point support beam structure, so as to improve the equivalent stiffness of the cutting system and suppress cutting chatter. S4. Perform sidewall milling and chip removal under high rigidity conditions, drive the right-angle milling head (120) to perform cutting operations, and continuously spray high-pressure fluid into the processing area through the high-pressure internal cooling chip removal channel (310), using the fluid recoil force and kinetic energy in the closed space to force the chips out of the profile cavity. Step S3 further includes: The vibration amplitude of the right-angle milling head (120) is monitored in real time, and the output pressure of the retractable fluid drive support mechanism (210) is dynamically adjusted according to the change of the vibration amplitude. When the vibration amplitude exceeds a preset threshold, the output pressure is increased to improve the system damping ratio until the vibration amplitude falls back to the stable cutting range. The steps in S4 include: S4.1 Set the fluid outlet pressure and flow rate of the high-pressure internal cooling chip-bursting channel (310) so that it forms an annular wrapping flow field with a preset flow velocity around the right-angle milling head (120); S4.2 The annular wrapping flow field is used to exchange and cool the high temperature generated by cutting, and the directional flow characteristics of the flow field are used to prevent the chips from accumulating at the expansion gap of the expandable fluid drive support mechanism (210). Following step S3 and before performing axial feed cutting, the method further includes: The contact pressure between the retractable fluid-driven support mechanism (210) and the inner wall of the profile cavity is detected, and it is confirmed that the contact pressure reaches a preset locking value to prevent displacement and slippage under the action of cutting reaction force. The retractable fluid-driven support mechanism (210) includes: An embedded fluid-driven cylinder (211) is disposed inside the housing of the right-angle milling head (120); The contoured support shoe (212) is connected to the piston rod end of the embedded fluid drive cylinder (211). The outer surface curvature of the contoured support shoe (212) matches the inner wall curvature of the profile cavity, which is used to increase the contact area and disperse the support stress. The length-to-diameter ratio of the long overhang drive shaft (110) is greater than 3:1, and the high-pressure internal cooling chip-removing channel (310) is a hollow sandwich structure coaxially arranged inside the long overhang drive shaft (110). Based on the cross-sectional area of ​​the profile's inner cavity Area occupied by the device Calculate the flow area of ​​the annular gap ; Set the output flow rate of the high-pressure internal cooling chip removal channel (310) The flow conservation formula must be satisfied: in, The minimum suspension velocity of the chips in the fluid. This is the flow resistance compensation coefficient, and its value range is... .

2. A milling apparatus for milling the inner cavity of a profile, applied to the milling method for milling the inner cavity of a profile as described in claim 1, characterized in that, include: The long overhang transmission assembly (100) includes a long overhang transmission shaft (110) with an outer diameter smaller than the cross-section of the inner cavity of a preset profile and a right-angle milling head (120) located at the end of the shaft. The internally supported damping assembly (200) includes a retractable fluid-driven support mechanism (210) integrated into the sidewall of the right-angle milling head (120), the retractable fluid-driven support mechanism (210) being capable of generating radial displacement relative to the right-angle milling head (120) under fluid pressure. The fluid circulation assembly (300) and the high-pressure internal cooling chip removal channel (310) are connected to an external fluid source through a rotary joint located at the input end of the long overhang drive shaft (110), and the outlet of the high-pressure internal cooling chip removal channel (310) points to the cutting edge area.

3. A milling device for milling the inner cavity of a profile according to claim 2, characterized in that, The surface of the conformal support shoe (212) is covered with a wear-resistant damping coating to provide additional frictional resistance and absorb high-frequency vibration energy when in contact with the inner wall of the profile cavity.

4. A milling device for milling the inner cavity of a profile according to claim 3, characterized in that, The device also includes a pressure adaptive control unit (400) integrated into the main control system, which is connected to the retractable fluid-driven support mechanism (210) for automatically maintaining a constant support pressure according to the cutting conditions.

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