Machining machine tool special for large thin-walled cylinder and machining technology of machining machine tool

Abstract

The invention relates to the technical field of processing machine tool equipment, and discloses a special processing machine tool for a large thin-walled cylinder and a processing technology thereof.The special processing machine tool for the large thin-walled cylinder comprises a special platform, a clamping tool is arranged on the special platform, and the coaxiality of the axis of a positioning element in the clamping tool and a main shaft of the machine tool is not larger than 0.05 mm; the diameter of the boring rod ranges from 750 mm to 850 mm, the wall thickness of the boring rod ranges from 70 mm to 90 mm, the length of the boring rod ranges from 15000 mm to 17000 mm, one end of the boring rod is connected with the power head, the other end of the boring rod is installed in the tailstock copper sleeve, and the coaxiality of the boring rod and the barrel is smaller than 0.8 mm. An inner supporting and outer holding bidirectional constraint structure comprises a half-form V-shaped block inner supporting piece and a hoop surrounding the outer circle of the barrel, so that the problem that the machining precision is difficult to guarantee due to the fact that most of traditional machining tools adopt a single inner supporting or outer clamping mode to fix the barrel and are prone to deformation under the influence of cutting force during machining is solved.

Description

Technical Field

[0001] The present invention relates to the technical field of machining machine tools, in particular to a special machining machine tool for large thin-walled cylinders and a machining process thereof. Background Art

[0002] With the research and development of new equipment in my country's aerospace, national defense, transportation, energy, chemical, papermaking and other industries, the inner hole processing of ultra-long and ultra-large thin-walled cylindrical parts has become a bottleneck restricting the manufacturing of these new equipment.

[0003] Most traditional machining centers use a single internal support or external clamp to fix the cylinder. Due to the unidirectional force, it is easy to cause local stress concentration or insufficient overall rigidity of the cylinder. During machining, it is easy to be deformed by the cutting force, making it difficult to ensure machining accuracy. Summary of the Invention

[0004] In response to the shortcomings of the existing technology, the present invention provides a special processing machine tool for large thin-walled cylinders and its processing technology, which solves the problem that most traditional processing machines use a single internal support or external clamping method to fix the cylinder. Due to the unidirectional force, the cylinder is easily deformed due to the influence of cutting force during processing, making it difficult to ensure the processing accuracy.

[0005] To achieve the above objectives, the present invention is implemented through the following technical solutions: A large thin-walled cylinder processing machine tool, comprising: A dedicated platform, on which a fixture is provided, wherein the coaxiality between the axis of the positioning element in the fixture and the main spindle of the machine tool is not greater than 0.05 mm; A boring bar having a diameter of 750-850 mm, a wall thickness of 70-90 mm, and a length of 15,000-17,000 mm, one end of which is connected to the power head and the other end is installed in the tailstock copper sleeve. The coaxiality between the boring bar and the barrel is less than 0.8 mm; The internal support and external embrace bidirectional constraint structure includes a half-shaped V-shaped block internal support and a hoop surrounding the outer circle of the cylinder. The coaxiality error between the positioning surface of the half-shaped V-shaped block and the outer circle of the cylinder flange is no more than 0.1mm, and the hoop is installed at an interval of 1.0-2.5m on the outer circle; A flat rotary disk radial tool holder is mounted on the boring bar and is used to drive the end turning tool to achieve radial feed.

[0006] By adopting the above technical solution, a bidirectional constraint structure of internal support and external clamping is utilized, including a Half-type V-shaped block internal support and a clamp surrounding the outer circle of the cylinder, and the coaxiality error between the positioning surface of the Half-type V-shaped block and the outer circle of the cylinder flange is not greater than 0.1mm, and the clamp is installed at an interval of 1.0-2.5m on the outer circle, thereby forming a stable clamp on the cylinder from both the inside and outside, thereby enhancing the rigidity of the thin-walled cylinder during the processing, reducing vibration and deformation, and thus improving the problem that most traditional processing machines use a single internal support or external clamping method to fix the cylinder. Due to unidirectional force, it is easy to cause local stress concentration or insufficient overall rigidity of the cylinder, and it is easy to be deformed by the cutting force during processing, making it difficult to ensure processing accuracy.

[0007] Preferably, the tailstock copper sleeve is made of tin bronze, and the matching tolerance with the tail journal of the boring bar is H7 / g6-H8 / g7, and the axial positioning error is no more than 0.05mm.

[0008] Preferably, the inner support member is driven by a hydraulic cylinder, the working surface angle of the V-shaped block is 85°-95°, and the surface roughness Ra is not greater than 3.2 μm.

[0009] Preferably, the clamp on the dedicated platform includes an inner support member and an outer clamp member that can be independently adjusted. The outer clamp member is a hoop structure surrounding the outer circle, and the clamping force of a single group of the hoop structure is 4-10kN.

[0010] A processing technology for a large thin-walled cylinder includes the following steps: S1. Process preparation: Assemble the cylinder segments and weld the upper and lower flanges to form the cylinder body. Perform flaw detection and tempering treatment. Make process plugs at the flanges at both ends of the cylinder body. Use a frame ring to support and clamp the cylinder body for alignment. Rough and fine machining of the outer diameter is performed on an outer cylindrical lathe with a diameter of 3.0-4.0×15-17mm. S2. Fix the cylinder: support the internal flange of the cylinder through the inner support member, and install the clamp structure at intervals of 1.0-2.5m on the outer circle to clamp it tightly, forming a two-way constraint structure with inner support and outer clamping; S3. Machine tool adjustment: Adjust the coaxiality between the axis of the positioning element in the fixture on the dedicated platform and the machine tool spindle to within 0.05 mm, install the fixed outer diameter of the cylinder into the fixture for positioning and clamping, insert the boring bar into the inner hole of the cylinder, connect one end of the boring bar to the power head, and install the other end into the copper sleeve of the tailstock for positioning and clamping; S4. Inner hole and inner groove processing: The power head drives the boring bar to realize the rotary motion of the boring cutter, and the worktable and the boring cutter holder move in batches to realize the feed motion. Each time the boring cutter holder moves on the boring bar, the position is 400-600 mm. After the rough boring of the inner hole and inner groove is completed, the inner hole and inner groove are finely bored after natural aging for 12-48 hours; S5. End face processing: Install the flat disc radial tool holder and end face turning tool on the boring bar to turn the end face of the inner hole of the cylinder to ensure that the circular runout of the end face relative to the inner hole axis is less than 1.5 mm.

[0011] Preferably, after each movement of the boring tool holder in S4, a laser tracker is used to detect the radial position of the boring tool head and the coaxiality with the rotation axis of the power head, with a detection accuracy of ±0.02 mm.

[0012] Preferably, when processing the inner groove in S4, the clamping method is the same as that of the inner hole processing, and a 0.8-1.5mm margin is left on each surface of the inner diameter and the groove. When processing the groove, the radial feed is automatically fed to a depth of 4-6mm with an accuracy of ±0.03mm, and the axial distance is ensured when processing the groove bottom.

[0013] Preferably, the frame ring in S1 is an adjustable rigid support structure, which is evenly distributed at intervals of 1.5-3.5m along the axial direction of the cylinder. The support strength is adjusted by bolts, and the cylinder axis is aligned in conjunction with a laser centering instrument.

[0014] Preferably, the natural aging in S4 is to stand for 12-48 hours in an environment with a temperature of 15-25° C. and a humidity of no more than 70%.

[0015] Preferably, the flat rotary disk radial tool holder in S5 is driven by a worm gear mechanism, with a feed speed of 0.05-1.5 mm / r, and the end face turning depth is controlled by CNC system programming.

[0016] The present invention provides a special machine tool for processing large thin-walled cylinders and a processing technology thereof. It has the following beneficial effects: 1. The present invention adopts an internal support and external clamping bidirectional constraint structure including a Half-type V-shaped block internal support and a clamp surrounding the outer circle of the cylinder, and the coaxiality error between the positioning surface of the Half-type V-shaped block and the outer circle of the cylinder flange is not greater than 0.1mm, and the clamp is installed at an interval of 1.0-2.5m on the outer circle, forming a stable clamp on the cylinder from both the inside and outside, thereby enhancing the rigidity of the thin-walled cylinder during the processing, reducing vibration and deformation, thereby improving the problem that most traditional processing machines use a single internal support or external clamping method to fix the cylinder. Due to unidirectional force, the cylinder is prone to local stress concentration or insufficient overall rigidity, and is easily deformed by the cutting force during processing, making it difficult to ensure processing accuracy.

[0017] 2. The present invention has a boring bar with a diameter of 750-850mm, a wall thickness of 70-90mm, a length of 15000-17000mm, one end of which is connected to the power head and the other end is installed in the tailstock copper sleeve. At the same time, the coaxiality of the boring bar and the cylinder is less than 0.8mm, so that the boring bar has sufficient rigidity and stability and maintains a high consistency with the axis of the cylinder, thereby being able to withstand cutting force and reduce its own deformation during processing, thereby improving the problem that most traditional processing machine tools use boring bars with small diameter, thin wall thickness or poor length adaptability. Due to insufficient rigidity or low coaxiality with the cylinder, the boring bar is easily deformed due to force or deadweight during processing, resulting in low processing accuracy of the inner hole and inner groove of the cylinder.

[0018] 3. The present invention provides a high-precision positioning reference for cylinder processing by arranging a fixture on a special platform and the coaxiality of the axis of the positioning element in the fixture with the machine tool spindle is not greater than 0.05mm, thereby ensuring that the installation position of the cylinder is highly consistent with the rotation center of the machine tool spindle, thereby improving the problem that most traditional machining machines use fixtures with low coaxiality accuracy between the positioning element and the spindle. Due to inaccurate positioning reference, the position of the cylinder will be offset during the machining process, resulting in low machining accuracy. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] Figure 1 Schematic diagram of the process steps of the present invention. DETAILED DESCRIPTION

[0020] The following will clearly and completely describe the technical solution of the present invention in conjunction with the accompanying drawings. Obviously, the embodiments described are only some embodiments of the present invention, not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative efforts are within the scope of protection of the present invention.

[0021] An embodiment of the present invention provides a machine tool specifically for processing large thin-walled cylinders, comprising: A dedicated platform is used, on which a fixture is installed. The coaxiality between the axis of the positioning element in the fixture and the main spindle of the machine tool shall not exceed 0.05mm; Boring bar: The diameter of the boring bar is 750-850mm, the wall thickness is 70-90mm, and the length is 15000-17000mm. One end of the boring bar is connected to the power head, and the other end is installed in the tailstock copper sleeve. The coaxiality between the boring bar and the barrel is less than 0.8mm. The internal support and external holding bidirectional constraint structure includes a half-type V-shaped block internal support and a hoop surrounding the outer circle of the cylinder. The coaxiality error between the positioning surface of the half-type V-shaped block and the outer circle of the cylinder flange is no more than 0.1mm, and the hoop is installed at an interval of 1.0-2.5m on the outer circle; The flat disc radial tool holder is installed on the boring bar and is used to drive the end turning tool to achieve radial feed.

[0022] Specifically, a fixture is set up on the special platform, and the coaxiality of the axis of the positioning element in the fixture and the main shaft of the machine tool is no more than 0.05mm, which can provide a high-precision positioning reference for the barrel processing. This setting ensures that the installation position of the barrel is highly consistent with the rotation center of the machine tool main shaft, so that the barrel remains stable during the processing, reducing the processing error caused by positioning deviation, thereby ensuring that the boring bar drives the boring tool to accurately process the inner hole and end face of the barrel, effectively improving the processing accuracy and product quality; the boring bar is designed with a diameter of 750-850mm, a wall thickness of 70-90mm and a length of 15000-17000mm, so that it has sufficient rigidity and strength to withstand the processing The cutting force during the process is reduced, and the deformation caused by deadweight and force is reduced; one end of the boring bar is connected to the power head and the other end is installed on the tailstock copper sleeve to form a stable support structure to ensure the stability of the boring bar rotation movement; the coaxiality of the boring bar and the cylinder is less than 0.8mm, which ensures the consistency of the boring bar axis and the cylinder axis, so that the boring cutter can accurately process the inner hole and inner groove of the cylinder to ensure the processing accuracy; the internal support and external holding bidirectional constraint structure uses the half-type V-shaped block inner support and the clamp surrounding the outer circle of the cylinder to fix the cylinder from both the inside and outside. The coaxiality error between the half-type V-shaped block positioning surface and the outer circle of the cylinder flange is no more than 0.1mm, which can achieve precise internal positioning and support to ensure The center position of the cylinder is accurate; the clamping hoop is installed at an interval of 1.0-2.5m on the outer circle, which can evenly apply external clamping force and enhance the overall rigidity of the cylinder. The two cooperate to form a stable clamping system, reduce the vibration and deformation of the thin-walled cylinder during processing, and provide reliable positioning guarantee for high-precision processing; the flat rotary disk radial tool holder is installed on the boring bar to drive the end turning tool to achieve radial feed, and can provide precise and controllable radial movement for the end turning tool on the basis of the rotary motion of the boring bar. Through this structure, the end turning tool can perform cutting processing along the radial direction of the cylinder inner hole, thereby realizing the turning of the end face of the cylinder inner hole, ensuring the end face processing accuracy, and meeting the position accuracy of the end face and the inner hole axis. Degree requirements; through the internal support and external holding bidirectional constraint structure, including the Half form V-shaped block internal support and the clamp surrounding the outer circle of the cylinder, and the coaxiality error between the positioning surface of the Half form V-shaped block and the outer circle of the cylinder flange is not more than 0.1mm, and the clamp is installed at an interval of 1.0-2.5m on the outer circle, forming a stable clamp on the cylinder from the inside and outside, thereby enhancing the rigidity of the thin-walled cylinder during the processing, reducing vibration and deformation, thereby improving the traditional processing machine tools that mostly use a single internal support or external clamp to fix the cylinder. Due to the unidirectional force, it is easy to cause local stress concentration or insufficient overall rigidity of the cylinder. It is easy to be deformed by the cutting force during processing, which makes it difficult to ensure the processing accuracy.

[0023] The tailstock copper sleeve is made of tin bronze, and the matching tolerance with the tail journal of the boring bar is H7 / g6-H8 / g7. The axial positioning error is no more than 0.05mm.

[0024] Specifically, by using tin bronze as the material for the tailstock copper sleeve, and utilizing its good wear resistance and anti-friction properties, the friction loss during the rotation of the boring bar can be reduced, ensuring the smooth movement of the boring bar; the matching tolerance with the shaft neck at the tail of the boring bar is H7 / g6-H8 / g7, forming a precise clearance fit, which not only ensures the flexible rotation of the boring bar but also controls the radial runout; the axial positioning error is no more than 0.05mm, which can effectively limit the axial movement of the boring bar, thereby ensuring the rigidity and positioning accuracy of the boring bar during processing, and providing stable motion transmission for the inner hole and end face processing of the cylinder.

[0025] The inner support is driven by a hydraulic cylinder, the working surface angle of the V-shaped block is 85°-95°, and the surface roughness Ra is not greater than 3.2μm.

[0026] Specifically, the internal support parts are driven by hydraulic cylinders to achieve uniform radial expansion and precise pressure of multiple groups of Half-form V-blocks, ensuring that the internal support force is stable and adjustable; the working surface angle of the V-block is 85°-95°, which can form an adaptive support contact angle with the outer circular surface of the cylinder flange and evenly distribute the support force; the surface roughness Ra is not greater than 3.2μm, which can reduce the friction resistance between the V-block and the flange surface, avoid scratching the workpiece, and at the same time ensure the fitting accuracy of the support surface, thereby enhancing the rigidity and stability of the internal support of the cylinder and effectively reducing the stress deformation during the processing process.

[0027] The fixture on the dedicated platform includes independently adjustable inner supports and outer clamps. The outer clamp is a hoop structure surrounding the outer circle. The clamping force of a single set of the hoop structure is 4-10kN.

[0028] Specifically, the fixture on the dedicated platform adopts a combination structure of independently adjustable internal supports and external clamps. The internal supports support the internal flange of the cylinder, and the external clamps are clamped from the outside through a clamping structure surrounding the outer circle. The internal and external bidirectional constraints form a stable support system; the clamping force of a single group of clamping structures is 4-10kN, and the clamping force can be adjusted according to the specifications of the cylinder and processing requirements, which not only ensures effective constraint on the thin-walled cylinder, prevents displacement and vibration during processing, but also avoids deformation of the cylinder due to excessive clamping force, thereby providing reliable positioning and clamping guarantees for high-precision processing.

[0029] Please see the attached Figure 1 , a large thin-walled cylinder processing technology, including the following steps: S1. Process preparation: Assemble the cylinder segments and weld the upper and lower flanges to form the cylinder body. Perform flaw detection and tempering treatment. Make process plugs at the flanges at both ends of the cylinder body. Use a frame ring to support and clamp the cylinder body for alignment. Rough and fine machining of the outer diameter is performed on an outer cylindrical lathe with a diameter of 3.0-4.0×15-17mm. S2. Fix the cylinder: Use internal support members to support the internal flange of the cylinder, and install clamp structures at intervals of 1.0-2.5m on the outer circle to clamp it tightly, forming a two-way constraint structure with internal support and external clamping; S3. Machine tool adjustment: Adjust the coaxiality between the axis of the positioning element in the fixture on the special platform and the machine tool spindle to within 0.05mm. Install the outer circle of the fixed cylinder into the fixture for positioning and clamping. Insert the boring bar into the inner hole of the cylinder, connect one end of the boring bar to the power head, and install the other end into the tailstock copper sleeve for positioning and clamping. S4. Inner hole and inner groove processing: The power head drives the boring bar to realize the rotary motion of the boring tool. The workbench and the boring tool holder move in batches to realize the feed motion. Each time the boring tool holder moves on the boring bar, the position is 400-600mm. After the rough boring of the inner hole and inner groove is completed, the inner hole and inner groove are finely bored after natural aging for 12-48 hours. S5. End face processing: Install the flat disc radial tool holder and end face turning tool on the boring bar, and turn the end face of the inner hole of the cylinder to ensure that the circular runout of the end face relative to the axis of the inner hole is less than 1.5mm.

[0030] Specifically, in the S1 process preparation, the cylinder segments are assembled and the upper and lower flanges are welded to form the cylinder. The flaw detection can detect welding defects to ensure the integrity of the cylinder structure; the tempering treatment can eliminate welding stress and improve material properties. Process plugs are made at the flanges at both ends of the cylinder to provide a positioning reference for subsequent clamping and processing; the intermediate frame ring supports the clamping and alignment, and the laser alignment instrument can compensate for the deformation of the cylinder by its own weight to ensure the accuracy of the cylinder axis. The outer circle is roughed and finely machined on an external cylindrical lathe with a diameter of 3.0-4.0×15-17m, which can provide an accurate external cylindrical reference surface for the cylinder, laying the foundation for subsequent inner hole and inner groove processing, and ensuring the position accuracy and dimensional accuracy between the processing surfaces; in the S2 step of fixing the cylinder, the inner support is used to fix the cylinder. The internal flange of the cylinder is supported, and at the same time, a clamping structure is installed at intervals of 1.0-2.5m on the outer circle to clamp it tightly, forming a two-way constraint structure with internal support and external embrace. The inner support provides support from the inside of the cylinder to enhance the rigidity of the cylinder and prevent deformation caused by internal hollowness; the clamps installed at intervals on the outer circle apply clamping force from the outside, and work together with the inner support to evenly distribute the force points and reduce local stress concentration. The two-way constraint structure is fixed at the same time inside and outside, which significantly improves the stability of the cylinder during processing and reduces the deformation risk of thin-walled cylinders caused by cutting force, deadweight and other factors, providing a reliable workpiece fixation state for subsequent high-precision processing; by adjusting the S3 machine tool, the coaxiality of the axis of the fixture positioning element on the special platform and the machine tool spindle is controlled Within 0.05mm, it provides a precise reference for the installation of the cylinder, ensuring that the cylinder is highly consistent with the center of rotation of the machine tool spindle; the outer circle of the fixed cylinder is installed in the fixture for positioning and clamping to avoid displacement of the cylinder during processing, and the boring bar is inserted into the inner hole of the cylinder, one end is connected to the power head, and the other end is installed in the tailstock copper sleeve for positioning and clamping, forming a stable support system to ensure the smooth rotation of the boring bar, reduce vibration and deformation caused by installation errors, ensure the coaxiality of the boring bar and the cylinder, and provide reliable equipment installation conditions for high-precision processing of the inner hole, inner groove and end face of the cylinder; in the processing of the S4 inner hole and inner groove, the power head drives the boring bar to realize the rotation of the boring tool and provide cutting power; the workbench and the boring tool holder move in steps to realize feeding The boring bar is moved 400-600mm each time, which can shorten the cantilever length of the boring bar, reduce the deformation of the boring bar during cutting, and ensure processing stability. After the rough boring of the inner hole and inner groove is completed, it is naturally aged for 12-48 hours to release the stress generated by rough processing and avoid the deformation of the workpiece caused by residual stress. Then, fine boring is carried out. Based on the stable workpiece state, the dimensional accuracy and surface quality of the inner hole and inner groove can be effectively guaranteed. In the S5 end face processing, a flat rotary disk radial tool holder and an end face turning tool are installed on the boring bar. The radial feed of the end face turning tool is driven by the rotation of the boring bar and the flat rotary disk radial tool holder to achieve turning processing of the end face of the inner hole of the cylinder. During processing, the circular runout of the end face relative to the inner hole axis is guaranteed to be less than 1.5mm, which can ensure the perpendicularity and coaxiality requirements between the end face and the inner hole axis, meet the position accuracy of the cylinder end face, form a coordinated geometric relationship between the various processing surfaces of the cylinder, and ensure the overall processing accuracy of large thin-walled cylinders.

[0031] In S4, after each movement of the boring tool holder, a laser tracker is used to detect the radial position of the boring tool head and the coaxiality with the rotation axis of the power head, with a detection accuracy of ±0.02mm.

[0032] Specifically, during S4 internal bore and groove machining, a laser tracker is used to detect the radial position of the boring tool head and its coaxiality with the rotary axis of the power head after each boring head movement. The detection accuracy is ±0.02mm, enabling real-time monitoring of the machining system's geometric accuracy. This detection can promptly identify coaxiality deviations caused by boring head movement or cutting forces, providing a basis for subsequent adjustments, ensuring the dimensional accuracy and coaxiality requirements for the barrel's internal bore and groove machining, and preventing error accumulation from impacting overall machining quality.

[0033] When machining the inner groove in S4, the clamping method is the same as that for the inner hole machining. A 0.8-1.5mm margin is left on each side of the inner diameter and groove. When machining the groove, the radial feed is automatically fed to a depth of 4-6mm with an accuracy of ±0.03mm. The axial distance is ensured when machining the groove bottom.

[0034] Specifically, in the S4 inner groove processing, the clamping method is the same as that of the inner hole processing, which can continue the positioning reference of the inner hole processing and reduce the position error caused by clamping change; leave a 0.8-1.5mm margin on each side of the inner diameter and groove to reserve correction space for subsequent fine processing and compensate for the stress deformation of rough processing; radial feed automatically feeds to a depth of 4-6mm with an accuracy of ±0.03mm, which can accurately control the groove size and ensure the groove width accuracy; the groove bottom is processed to ensure the axial distance and the axial position accuracy of the inner groove, thereby realizing the precise processing of each size of the inner groove and forming a coordinated geometric relationship with the inner hole.

[0035] The S1 center frame ring is an adjustable rigid support structure, evenly distributed along the axial direction of the cylinder at intervals of 1.5-3.5m. The support strength is adjusted by bolts, and the cylinder axis is aligned with the laser alignment instrument.

[0036] Specifically, in the S1 process preparation, the frame ring adopts an adjustable rigid support structure, which is evenly distributed at intervals of 1.5-3.5m along the axial direction of the cylinder. The support strength can be adjusted by bolts, and the cylinder axis can be aligned with the laser centering instrument. It can provide multi-point adjustable rigid support for the ultra-long thin-walled cylinder, compensate for the deformation of the cylinder due to its own weight, ensure the coaxiality of the cylinder axis and the axis of the processing equipment, reduce vibration and deformation during the processing process, provide precise positioning reference for subsequent outer circle and inner hole processing, and ensure the position accuracy of each processing surface.

[0037] The natural aging in S4 is to stand still for 12-48 hours in an environment with a temperature of 15-25℃ and a humidity of no more than 70%.

[0038] Specifically, in the processing of S4 inner holes and inner grooves, natural aging is carried out by standing still for 12-48 hours in an environment with a temperature of 15-25°C and a humidity of no more than 70%. The ambient temperature and humidity conditions can be used to slowly release the processing stress of the barrel after rough boring, eliminate the internal stress concentration caused by cutting, avoid the deformation of the barrel caused by residual stress, and provide a stable workpiece state for subsequent fine boring, thereby ensuring the finishing accuracy of the inner hole and inner groove.

[0039] The radial tool holder of the S5 flat rotary table is driven by a worm gear mechanism with a feed speed of 0.05-1.5mm / r. The end turning depth is controlled by CNC system programming.

[0040] Specifically, during S5 end-face machining, the flat-rotating radial toolholder is driven by a worm gear mechanism, with a feed rate of 0.05-1.5mm / r. The end-face turning depth is controlled through CNC system programming, enabling precise radial feed control of the end-face turning tool. The transmission characteristics of the worm gear mechanism ensure smooth feed motion and transmission accuracy. The CNC system programming precisely sets the turning depth according to machining requirements. Combined with the rotary motion of the boring bar, high-precision turning of the end face of the inner bore is achieved, ensuring that the circular runout of the end face relative to the inner bore axis is less than 1.5mm, meeting the positional accuracy requirements of the end face and the inner bore.

[0041] Process preparation before machining the inner hole and end face of the cylinder: To ensure the quality of machining extra-long, extra-large, thin-walled cylinders on specialized boring machines, we adhere to the principle of "base surface first, roughing first, finishing later." This means that after the cylinder segments are assembled and the upper and lower flanges are welded to form the cylinder, flaw detection and tempering are performed. Process plugs are installed at the flanges at both ends of the cylinder, and support rings are used in the middle to support and align the cylinder. The support rings are adjustable rigid structures, evenly spaced 2-3 meters along the axial direction. The support force is adjusted by bolts. The outer diameter is roughed and finished on a Φ3.5X16m external lathe. This provides a benchmark for machining the inner bore of the cylinder. After the outer diameter of the cylinder part is machined, clamps are installed at intervals of 1.2-2 meters on the outer diameter to control deformation during the machining of the thin-walled inner bore and improve the rigidity of the cylinder.

[0042] Special machine tool adjustment before processing the barrel: First, adjust the axis of the positioning element in the fixture on the dedicated platform to a coaxiality of 0.03 mm with the machine tool spindle. The machine tool spindle serves as the axis of the boring bar. Then, install the outer diameter of the barrel, with the clamp attached, into the V-shaped seat of the fixture for positioning and clamping. Insert the boring bar into the inner bore of the barrel. Connect one end of the boring bar to the power unit, and install the other end into the copper sleeve of the tailstock for positioning and clamping. Install the boring bar holder 600 mm from the power unit. Using a dial indicator attached to the boring bar holder, check the radial runout of the outer diameter of each end of the barrel. Adjust the fixture to maintain the coaxiality of the boring bar and barrel to less than 0.5 mm.

[0043] Processing process of inner hole and end face of cylinder: The cutting motion for machining ultra-long, ultra-large, thin-walled, multi-stepped internal bore components: The main motion is achieved by the power head driving the boring bar to achieve the rotational motion of the boring tool. The feed motion is achieved by the worktable and boring head moving in stages. To minimize the length of the boring bar, the boring head is moved on the boring bar, with each movement not exceeding 500mm. After rough boring of the internal bore, the internal bore is finish bored after natural aging to eliminate roughing stresses. Natural aging refers to 24 hours of stabilization at room temperature.

[0044] The inner groove is processed by professional machine tools. The clamping method is the same as that of the inner hole processing. A 1mm margin is left on each side of the inner diameter and the groove. When processing the groove, the radial feed is automatically controlled by the CNC system to feed to a depth of 5mm, and the axial distance is guaranteed when processing the groove bottom.

[0045] After the inner hole of the cylinder is processed, the boring tool holder is removed from the boring bar, and the flat rotary disk radial tool holder and the end turning tool are installed to realize the end turning of the inner hole of the cylinder.

[0046] While embodiments of the present invention have been shown and described, it will be appreciated by those skilled in the art that various changes, modifications, substitutions, and variations may be made to these embodiments without departing from the principles and spirit of the invention, and that the scope of the invention is defined by the appended claims and their equivalents.

Claims

1. A large thin-walled cylinder special processing machine tool, characterized in that: include: A dedicated platform, on which a fixture is provided, wherein the coaxiality between the axis of the positioning element in the fixture and the main spindle of the machine tool is not greater than 0.05 mm; A boring bar having a diameter of 750-850 mm, a wall thickness of 70-90 mm, and a length of 15,000-17,000 mm, one end of which is connected to the power head and the other end is installed in the tailstock copper sleeve. The coaxiality between the boring bar and the barrel is less than 0.8 mm; The internal support and external embrace bidirectional constraint structure includes a half-shaped V-shaped block internal support and a hoop surrounding the outer circle of the cylinder. The coaxiality error between the positioning surface of the half-shaped V-shaped block and the outer circle of the cylinder flange is no more than 0.1mm, and the hoop is installed at an interval of 1.0-2.5m on the outer circle; A flat rotary disk radial tool holder is mounted on the boring bar and is used to drive the end turning tool to achieve radial feed.

2. A large thin-walled cylinder processing machine tool according to claim 1, characterized in that: The tailstock copper sleeve is made of tin bronze, and the matching tolerance with the tail journal of the boring bar is H7 / g6-H8 / g7, and the axial positioning error is no more than 0.05mm.

3. A large thin-walled cylinder processing machine tool according to claim 1, characterized in that: The inner support member is driven by a hydraulic cylinder, the working surface angle of the V-shaped block is 85°-95°, and the surface roughness Ra is not greater than 3.2 μm.

4. A large thin-walled cylinder processing machine tool according to claim 1, characterized in that: The clamp on the dedicated platform includes an inner support member and an outer clamp member that can be independently adjusted. The outer clamp member is a hoop structure surrounding the outer circle. The single-group clamping force of the hoop structure is 4-10kN.

5. A process for processing a large thin-walled cylinder, using a large thin-walled cylinder processing machine tool according to any one of claims 1 to 4, characterized in that: The following steps are involved: S1. Process preparation: Assemble the cylinder segments and weld the upper and lower flanges to form the cylinder body. Perform flaw detection and tempering treatment. Make process plugs at the flanges at both ends of the cylinder body. Use a frame ring to support and clamp the cylinder body for alignment. Rough and fine machining of the outer diameter is performed on an outer cylindrical lathe with a diameter of 3.0-4.0×15-17mm. S2. Fix the cylinder: support the internal flange of the cylinder through the inner support member, and install the clamp structure at intervals of 1.0-2.5m on the outer circle to clamp it tightly, forming a two-way constraint structure with inner support and outer clamping; S3. Machine tool adjustment: Adjust the coaxiality between the axis of the positioning element in the fixture on the dedicated platform and the machine tool spindle to within 0.05 mm, install the fixed outer diameter of the cylinder into the fixture for positioning and clamping, insert the boring bar into the inner hole of the cylinder, connect one end of the boring bar to the power head, and install the other end into the copper sleeve of the tailstock for positioning and clamping; S4. Inner hole and inner groove processing: The power head drives the boring bar to realize the rotary motion of the boring cutter, and the worktable and the boring cutter holder move in batches to realize the feed motion. Each time the boring cutter holder moves on the boring bar, the position is 400-600 mm. After the rough boring of the inner hole and inner groove is completed, the inner hole and inner groove are finely bored after natural aging for 12-48 hours; S5. End face processing: Install the flat disc radial tool holder and end face turning tool on the boring bar to turn the end face of the inner hole of the cylinder to ensure that the circular runout of the end face relative to the inner hole axis is less than 1.5 mm.

6. A processing technology for a large thin-walled cylinder according to claim 5, characterized in that: After each movement of the boring tool holder in S4, a laser tracker is used to detect the radial position of the boring tool head and the coaxiality with the rotation axis of the power head, with a detection accuracy of ±0.02mm.

7. The processing technology of a large thin-walled cylinder according to claim 5 is characterized in that: When processing the inner groove in S4, the clamping method is the same as that of the inner hole processing. A 0.8-1.5mm margin is left on each side of the inner diameter and the groove. When processing the groove, the radial feed is automatically fed to a depth of 4-6mm with an accuracy of ±0.03mm. The axial distance is ensured when processing the groove bottom.

8. The processing technology of a large thin-walled cylinder according to claim 5, characterized in that: The frame ring described in S1 is an adjustable rigid support structure, which is evenly distributed at intervals of 1.5-3.5m along the axial direction of the cylinder. The support strength is adjusted by bolts, and the cylinder axis is aligned with the laser centering instrument.

9. The processing technology of a large thin-walled cylinder according to claim 5, characterized in that: The natural aging in S4 is to stand still for 12-48 hours in an environment with a temperature of 15-25° C. and a humidity of no more than 70%.

10. The processing technology of a large thin-walled cylinder according to claim 5, characterized in that: The flat rotary disk radial tool holder in S5 is driven by a worm gear mechanism, with a feed speed of 0.05-1.5 mm / r, and the end face turning depth is controlled by CNC system programming.

Images