An Additive Manufacturing Equipment and Process for Strengthening the Surface Tooth Profile Roller Pressure of Tubular Parts by Toughness

Abstract

The present invention discloses an additive manufacturing cylindrical part surface tooth-shaped roll pressure toughening device and process. The additive manufacturing cylindrical part surface tooth-shaped roll pressure toughening device includes a lower die base, an upper die base and a guiding column. A rotating base is arranged inside the lower die base, and a positioning component is arranged on the rotating base. An inner wall ultrasonic roller device is arranged on the bottom surface of the upper die base. The inner wall ultrasonic roller device includes an inner wall radial groove base, an inner wall roller base and an inner wall roller. Outer wall ultrasonic roller devices are arranged on both ends of the inner wall ultrasonic roller device. The outer wall ultrasonic roller device includes an outer wall radial groove base, an outer wall roller base and an outer wall roller. Ultrasonic vibration devices are respectively arranged on the inner wall radial groove base and the outer wall radial groove base. The present invention can efficiently, with high quality and high freedom, achieve gradient toughening of the entire internal and external wall tissues and properties, solve the problem that it is difficult to achieve deep tissue modification of cylindrical parts without changing their structures, the roll pressing strengthening process is stable, and the gradient change of the tissues is more significant.

Description

Technical Field

[0001] The present invention belongs to the technical field of metal roll forming, and specifically relates to an additive manufacturing cylindrical part surface tooth-shaped roll press strengthening equipment and process. Background Art

[0002] Aerospace is a key direction for the development of high-end equipment manufacturing. The overall ring of an aeroengine and the rocket cabin section of a space rocket are core components in the aerospace field, and they have strict requirements in terms of structure and service performance. The structural characteristics of these components usually manifest as large sizes, complex geometric shapes, and often need to withstand extreme mechanical loads, temperature fluctuations, vibrations and other environments. Service requirements include the improvement of surface strength, fatigue resistance and corrosion resistance, etc. In order to meet these performance requirements, the surface of the components usually needs to be strengthened, and the organizational structure needs to be optimized through appropriate heat treatment or plastic processing techniques to ensure the reliability and stability of the components during long-term use. If traditional long-process technologies are used for large-scale integral precision components, residual stress evolution and dimensional out-of-control problems will be caused due to phase transformation and thermal / mechanical coupling effects, resulting in deterioration of shape and properties. In contrast, additive manufacturing (AM) technology has significant advantages, especially when dealing with complex shapes and large-scale precision components.

[0003] However, the workpieces produced by laser additive manufacturing usually cannot be directly used, mainly because their surface layer structure and microstructure are difficult to fully meet strict service requirements. First, during the additive manufacturing process, rough melt channel textures and micro-defects are likely to form on the surface. These defects are likely to become the starting points of fatigue cracks under cyclic stress, significantly reducing the fatigue life. Second, the microstructure of additive manufacturing parts is non-uniform. The surface layer grains may be finer but have higher brittleness, while there may be coarse columnar grains or texture distributions inside, resulting in an unsatisfactory performance gradient. Components such as rocket cabin sections usually require a strong and tough surface layer and a ductile interior, which requires a special strengthening process to form a reasonable performance gradient. For large-scale complex parts produced by additive manufacturing, traditional strengthening processes (such as heat treatment, cold working or machining) face significant challenges when implementing their gradient strengthening, especially on the premise of not damaging the one-time forming structure. The heat treatment process may cause deformation and stress redistribution of additive manufacturing parts, damaging their accuracy and microstructure. Traditional machining methods are also difficult to uniformly achieve plastic deformation on complex geometries, and excessive machining may lead to surface defects or grain structure changes, thus affecting the overall performance of the material. However, gradient strengthening is crucial for high-load structures such as rockets. By achieving gradient strengthening on the inner and outer surfaces of cylindrical parts, the surface layer grains can be refined to improve strength and fatigue resistance, while the interior remains with coarser grains to ensure toughness. This structural optimization can effectively cope with temperature changes, mechanical loads and dynamic impacts in extreme environments, improving the reliability and service life of components.

[0004] At present, the common metal surface deformation strengthening technologies include shot peening and surface rolling technology. The deformation hardening layer of shot peening is relatively thin, generally 0.15 - 1.5 mm. Although it can adapt to the surface of complex shapes, it is mainly suitable for the requirements mainly for fatigue resistance. For the requirements with a relatively large demand for the thickness of the modified layer, surface rolling technology is mostly used, that is, under the action of a certain pressure, a rolling ball or a roller shaft rolls or extrudes the surface of the machined part, causing it to undergo plastic deformation to form a strengthening layer. At present, simple improvement or replacement of the rolling tool can carry out limited microstructure control, but it also has the limitations of surface rolling technology, and is only applicable to some flat parts and groove parts with simple shapes, etc., and cannot be applied to the surface of parts with complex shapes, such as additively manufactured integral cylindrical parts. Based on the requirement of a relatively thick gradient tissue hardening, a relatively large rolling pressure is required during traditional strengthening and toughening rolling to obtain a larger thickness of the deformation layer, but too large a rolling pressure will cause uneven deformation on the metal surface, resulting in the generation of surface defects. Different metal materials also have different hardness and microstructures. Especially for harder metals or additively manufactured components with uneven surface hardness, this phenomenon will be more obvious. Summary of the Invention

[0005] To solve the above problems, the present invention patent provides a surface tooth-shaped rolling strengthening and toughening device and process for additively manufactured cylindrical parts. By adopting an innovative process and equipment design scheme, through the tooth-shaped rolling and flattening process on the inner and outer surfaces of the cylinder wall, the surface material undergoes plastic deformation and accumulates plastic strain, thereby forming a structure with a gradient tissue. In this process, the cylindrical part is fixed by the bottom die and rotates around the central axis. The core components of the processing equipment include four helical tooth rollers and a cylindrical roller body, which are respectively distributed in pairs on the inner and outer surfaces at both ends of the cylindrical part. Continuous rolling with helical tooth rollers can make the force on the cylinder wall have better continuity, and the two pairs of helical tooth rollers have opposite helix directions. Through the synchronous feeding movement in the radial and axial directions, a strengthening path with a double helix shape can be formed on the inner and outer wall surfaces, thereby forming a cross-shaped tooth mark different from the traditional wavy shape. This tooth mark can provide more accumulated plastic strain in one pass, and at the same time requires a lower feeding depth during flattening, thereby effectively reducing the deformation defects of wall thickness reduction and excessive elongation. And through this path design, not only can the entire surface of the cylinder wall be fully covered, but also the surface layer and the inner layer can be gradually strengthened without destroying the macroscopic structure of the cylindrical part, realizing the directional control of the gradient tissue.

[0006] Different from traditional surface deformation strengthening, gradient strengthening requires a deeper feed rate. In order to avoid secondary processing defects and improve the toughening effect at the same time, the present invention also proposes a tooth-shaped roller toughening process combined with two-dimensional ultrasonic vibration. The two-dimensional ultrasonic vibration is set to the meshing direction and the vertical meshing direction of the helical roller respectively. The two-dimensional vibration trajectory is an elliptical plane, whose major axis is consistent with the meshing direction, and the vibration plane is tangent to the helical roller. By controlling the amplitude and phase in the two excitation directions and realizing the combination of the two directions, the shear angle can be increased, which can more effectively help optimize the deformation in the helical tooth embossing direction. The roller flat wheel adopts a simple radial plus tangential two-dimensional vibration, which helps to promote stress transfer, alleviate excessive elongation and instability of the cylinder wall, and ensure dimensional stability after strengthening.

[0007] In order to solve the above technical problems, a technical solution adopted by the present invention is:

[0008] An additive manufacturing cylindrical part surface toothed roller toughening equipment comprises a lower die seat, an upper die seat located above the lower die seat, and a plurality of guide columns fixedly arranged between the lower die seat and the upper die seat, a rotating base is arranged in the lower die seat, a positioning assembly is arranged on the rotating base, a first vertical positioning mechanism is arranged on the bottom surface of the upper die seat, an inner wall ultrasonic roller device is fixedly connected to the bottom positioning end of the first vertical positioning mechanism, and the inner wall ultrasonic roller device comprises an inner wall radial groove seat, an inner wall roller seat symmetrically slidably arranged at both ends of the inner wall radial groove seat, and an inner wall roller rotatably arranged at the outer end of the inner wall roller seat and arranged vertically with its axis;

[0009] Two groups of outer wall ultrasonic roller devices are symmetrically arranged at both ends of the inner wall ultrasonic roller device, and each group of outer wall ultrasonic roller devices includes an outer wall radial groove seat, an outer wall roller seat slidably arranged in the outer wall radial groove seat, and an outer wall roller rotatably arranged at the end of the outer wall roller seat and arranged to be assembled with the inner wall roller. The outer wall ultrasonic roller device is connected to the guide column on the corresponding side through a second vertical positioning mechanism. Both the inner wall roller and the outer wall roller are helical cylindrical gears with opposite spiral directions or are cylindrical roller bodies.

[0010] Ultrasonic vibration devices are also respectively arranged on the inner wall radial groove seat and the outer wall radial groove seat.

[0011] Furthermore, the inner wall ultrasonic roller device also includes a horizontal bidirectional positioning mechanism fixedly arranged on the outer wall of the inner wall radial groove seat, and the two inner wall roller seats are respectively fixedly connected to the two side positioning output ends of the horizontal bidirectional positioning mechanism, and the two inner wall roller seats move toward or away from each other synchronously.

[0012] Further, the horizontal two-way positioning mechanism includes a fixedly arranged first driving motor, a horizontally rotatable two-way screw rod, and first nut blocks respectively threadedly connected to both ends of the two-way screw rod. One end of each first nut block penetrates through the inner wall radial groove seat and is fixedly connected to the inner wall roller seat, and the output shaft end of the first driving motor is in transmission connection with the middle of the two-way screw rod through a gear pair.

[0013] Further, first radial guide grooves are respectively formed on the inner surfaces of the upper and lower walls of the inner wall radial groove seat, and the upper and lower ends of the inner wall roller seat are respectively slidably embedded in the first radial guide grooves.

[0014] Further, the outer wall ultrasonic roller device further includes a horizontal positioning mechanism fixedly arranged on the outer wall of the outer wall radial groove seat. The horizontal positioning mechanism includes a fixedly arranged second driving motor, a rotatable screw rod, and a second nut block threadedly connected to the screw rod. One end of the second nut block penetrates through the outer wall radial groove seat and is fixedly connected to the outer wall roller seat, and the output shaft end of the second driving motor is in transmission connection with one end of the screw rod.

[0015] Further, second radial guide grooves are respectively formed on the inner surfaces of the upper and lower walls of the outer wall radial groove seat, and the upper and lower ends of the outer wall roller seat are respectively slidably embedded in the second radial guide grooves.

[0016] Further, the ultrasonic vibration device includes two groups of ultrasonic vibrators, which are respectively arranged on the vertical side surfaces far from the inner wall roller / outer wall roller of the inner wall roller seat and the adjacent vertical side surfaces.

[0017] Further, the axes of the inner wall roller and the outer wall roller are located in the same vertical plane, and the rotating shaft of the rotating base is located in this vertical plane.

[0018] There is also provided a surface tooth-shaped roller pressing and toughening process for additively manufactured cylindrical parts, including the following steps:

[0019] S1. Fix the cylindrical part on the rotating base through the positioning assembly;

[0020] S2. The inner wall roller and the outer wall roller adopt helical cylindrical gears. The inner wall roller and the outer wall roller are initially positioned at the lowest position, and the initial position of the inner wall roller and the outer wall roller is adjusted so that the radial distance between each roller and the cylinder wall is the same;

[0021] S3. Set the workpiece rotation speed, roller radial feed and axial feed parameters, and ultrasonic vibration parameters;

[0022] S4. Start the ultrasonic vibration device, and the two groups of inner wall rollers and outer wall rollers synchronously feed radially towards the cylinder wall at a preset feed speed to a preset distance, so that the inner wall roller bites into the inner cylinder wall and the outer wall roller bites into the outer cylinder wall;

[0023] S5. The rotary base drives the cylindrical part to rotate at a preset uniform rotation speed. After a preset time, the cylindrical part rotates one week, and each roller synchronously feeds axially upward at a preset axial width of a single roller until the top ends of all the rollers exceed the uppermost end of the cylindrical part, then the final rolling is completed and the rollers are radially reset, and the equipment pauses.

[0024] S6. Each roller is replaced with a cylindrical roller body of the same diameter and positioned at the lowest position, and steps S4 to S5 are repeated to complete the rolling flat of the cylindrical wall of the cylindrical part.

[0025] S7. The radially feeding distance of each roller biting into the wall thickness is gradually reduced by a preset reduction amount, and steps S3 to 6 are repeated for a preset number of times to complete the gradient tissue strengthening and toughening of the cylindrical wall.

[0026] S8. The cylindrical part is taken off for heat treatment optimization and surface repair.

[0027] Furthermore, the radially feeding distance of the cylindrical roller body is less than that of the helical cylindrical gear in the same pass.

[0028] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0029] 1. The present invention aims at realizing the gradient tissue strengthening and toughening of the cylindrical parts manufactured by one-time additive manufacturing, and proposes a process for using tooth-shaped rolling and rolling flat to perform gradient tissue strengthening and toughening on the cylindrical parts manufactured by additive manufacturing, as well as an overall process equipment designed according to the integral forming process characteristics of the cylindrical parts manufactured by additive manufacturing. Without changing the structure of the workpiece, it can efficiently, high-quality and highly freely realize the gradient strengthening and toughening of the whole inner and outer wall tissues and properties, solve the problem that it is difficult to realize the deep tissue modification of the formed cylindrical parts without changing their structures, and the overall structure of the equipment is innovated.

[0030] 2. The roller device of the present invention adopts two-dimensional ultrasonic vibration assistance. By ultrasonic vibration, the processing force is reduced, the surface quality is improved, the material deformation ability is enhanced, the residual stress is reduced, and the processing efficiency is increased. It solves a series of problems such as surface defects, insufficient material fluidity, easy wear of the rollers, and low efficiency caused by deep tissue modification at large feed rates, effectively realizes the effects of reducing the yield strength of the material, reducing the flow stress, relieving local stress concentration, optimizing the microstructure of the surface layer and near-surface layer, and promoting more uniform plastic deformation on the surface, forms a more uniform and refined grain structure, improves the surface strength and fatigue resistance, and at the same time reduces the risk of generating defects such as cracks.

[0031] 3. The present invention uses helical roller wheels for roller compaction strengthening. During the spiral line feeding, local progressive biting can be achieved, making the biting more sufficient and the rotation of the roller wheels more stable. Moreover, for the helical tooth structure, when the biting of the previous tooth has not ended, the next tooth has already started to bite in, resulting in more sufficient, continuous, and progressive biting. Compared with the traditional tooth-shaped roller compaction, more stable roller wheel feeding and rotation as well as more stable roller pressure are achieved, making the roller pressure more uniform and the roller compaction process more stable.

[0032] 4. The present invention uses symmetric double helical roller wheels, which can achieve double tooth pressing in one pass. Its double spiral cross trajectory and mutually perpendicular cross tooth marks make the tooth pressing efficiency higher. While being able to more effectively accumulate plastic strain, it can reduce the tooth mark depth, thereby alleviating the excessive thinning and elongation of the cylinder wall during roller leveling.

[0033] 5. The present invention uses multi-pass tooth rolling and roller leveling processes, and the feeding amount of the roller wheels to the cylinder wall gradually decreases in each pass. This can alleviate surface defect problems such as crack initiation and stress concentration caused by large feeding amounts, and at the same time make the gradient change of the structure more significant. BRIEF DESCRIPTION OF THE DRAWINGS

[0034] Figure 1 is a three-dimensional structural schematic diagram of the roller compaction and toughening equipment of the present invention;

[0035] Figure 2 is a three-dimensional structural schematic diagram of the assembled state of the cylindrical part on the roller compaction and toughening equipment;

[0036] Figure 3 is a three-dimensional structural schematic diagram of the inner wall ultrasonic roller wheel device;

[0037] Figure 4 is a structural schematic diagram of the assembled state of the ultrasonic vibration device on the inner wall roller wheel seat;

[0038] Figure 5 is a three-dimensional structural schematic diagram of the outer wall ultrasonic roller wheel device;

[0039] Figure 6 is Figure 1 an enlarged structural schematic diagram of part A in

[0040] Figure 7 is an equivalent plastic strain diagram of the cylindrical part after one-pass bottom ring tooth rolling obtained by simulation;

[0041] Figure 8 is an equivalent plastic strain diagram of the cylindrical part after one-pass multi-layer spiral tooth rolling obtained by simulation;

[0042] Figure 9 is a radial distribution and curve of the plastic strain of the cylinder wall during the one-pass tooth rolling stage obtained by simulation;

[0043] Figure 10 It is the radial distribution and curve of the cumulative plastic strain of the cylinder wall in the first pass roller leveling stage obtained by simulation;

[0044] Figure 11 It is a schematic diagram of the wall thickness and height changes of the cylinder wall in the first pass roller leveling stage obtained by simulation.

[0045] In the figure: 1. Lower die base; 2. Upper die base; 3. Guide column; 4. Rotating base; 5. Positioning component; 501. Positioning inner core; 502. Positioning pressing ring; 503. Positioning wedge block; 6. First vertical positioning mechanism; 7. Inner wall ultrasonic roller device; 701. Inner wall radial groove seat; 702. Inner wall roller seat; 703. Inner wall roller; 704. Horizontal two-way positioning mechanism; 7041. First driving motor; 7042. Two-way screw; 7043. First nut block; 7044. Gear pair; 8. Outer wall ultrasonic roller device; 801. Outer wall radial groove seat; 802. Outer wall roller seat; 803. Outer wall roller; 804. Horizontal positioning mechanism; 8041. Second driving motor; 8042. Screw; 8043. Second nut block; 9. Second vertical positioning mechanism; 901. Third driving motor; 902. Lifting gear; 903. Rack; 10. Ultrasonic vibration device; 100. Tubular part. Specific embodiments

[0046] The following will elaborate on the preferred embodiments of the present invention in conjunction with the accompanying drawings, so that the advantages and features of the present invention can be more easily understood by those skilled in the art, thereby making the protection scope of the present invention more clearly defined.

[0047] It should be noted that when a component is referred to as "installed on" another component, it can be directly on the other component or there can also be an intermediate component. When a component is considered to be "set on" another component, it can be directly set on the other component or there may be an intermediate component at the same time. When a component is considered to be "fixed to" another component, it can be directly fixed to the other component or there may be an intermediate component at the same time.

[0048] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by those skilled in the technical field to which the present invention belongs. The terms used in the description of the present invention herein are only for the purpose of describing specific embodiments and are not intended to limit the present invention. The term "or / and" used herein includes any and all combinations of one or more of the related listed items.

[0049] Refer to the attached Figures 1 to 6, An additive manufacturing cylindrical part surface tooth profile roller pressure toughening device, including a lower die base 1, an upper die base 2 located above the lower die base 1, and four guiding columns 3 fixedly arranged between the lower die base 1 and the upper die base 2. The lower die base 1 is a hollow disc, the upper die base 2 is a solid disc with the same diameter, and the guiding columns 3 are cylinders, and are evenly arranged at the front, rear, left, and right four positions on the top surface of the lower die base 1 to form a stable support frame. Obviously, a gantry arch can also be used instead.

[0050] A rotating base 4 is arranged inside the lower die base 1. The rotating base 4 is used to place the cylindrical part 100 to be strengthened and provide the power for the rotation of the cylindrical part 100, and its bottom is driven by a rotating power output device (such as a motor driving mechanism). In this embodiment, the rotating base 4 adopts the torsion platform of an existing torsion forming device, and the rotation process parameters of the rotating base 4 can be directly set by using the control system supporting the torsion forming device. At the same time, the control logic program of other working components is added to its control system, and the motion logic control of each functional component of this device can be realized.

[0051] A positioning component 5 is arranged on the rotating base 4. The positioning component 5 includes a positioning inner core 501 fixedly arranged at the center of the top surface of the rotating base 5 and a positioning pressure ring 502 located outside the positioning inner core 501. Among them, the positioning inner core 501 is a disc structure, coaxially arranged with the rotating base 5, and its outer diameter matches the inner wall diameter of the bottom end of the cylindrical part 100. After the cylindrical part 100 is placed on the rotating base 4, its bottom end is sleeved outside the positioning inner core 501, and its axial center position and its axial perpendicularity (based on the rotation axis of the rotating base 4) are ensured within the preset error range through the cooperation between its inner wall and the outer cylindrical side surface of the positioning inner core 501, avoiding problems such as uneven large-area stress distribution and instability caused by workpiece inclination. The positioning pressure ring 502 is an annular plate, coaxially arranged with the positioning inner core 501, and is fastened to the top surface of the rotating base 4 by bolts. A plurality of (4 in this embodiment) pressing wedges 503 are evenly distributed around its central axis on its top surface. The bottom end of the pressing wedge 503 and the top end of the positioning pressure ring 502 are slidably matched through a dovetail groove structure arranged along the radial direction of the positioning pressure ring 502. An adjusting screw (not shown in the figure) is threadedly connected to the outer side surface of the pressing wedge 503, and the adjusting screw is rotatably arranged on the outer wall of the positioning pressure ring 502. By rotating the adjusting screw, the radial position of the pressing wedge 503 on the positioning pressure ring 502 can be adjusted. Then, after the cylindrical part 100 and the positioning inner core 501 are positioned and matched, by adjusting the radial positions of each positioning wedge 503, the cylindrical part 100 can be clamped and fixed in cooperation with the positioning inner core 501, and the pressures of each pressing wedge 503 are kept consistent (the surface deformation after pressing should be within 2 - 4 mm), preventing the cylindrical part 100 from sliding during the rotary processing and affecting the subsequent roller pressing strengthening process due to uneven friction.

[0052] A first vertical positioning mechanism 6 is arranged on the bottom surface of the upper die base 2, and a bottom positioning end of the first vertical positioning mechanism is fixedly connected with an inner wall ultrasonic roller device 7. The inner wall ultrasonic roller device 7 is used for roll strengthening the inner wall surface of the tubular part 100, and the first vertical positioning mechanism 6 is used for the uniform feeding of the inner wall ultrasonic roller device 7 in the axial direction of the tubular part 100, so that the inner wall ultrasonic roller device 7 can achieve the full coverage of the inner wall in the axial direction by means of axial spiral layer-by-layer superposition. For this purpose, the first vertical positioning mechanism 6 adopts a power mechanism that can be fed and positioned segment by segment. In this embodiment, an electric cylinder is preferably used, which can not only meet the need of uniform linear feeding in the straight line direction, but also achieve precise positioning. At the same time, the feeding distance and speed can be conveniently set and adjusted by adjusting the control parameters, which is flexible and convenient to use. Moreover, the electric cylinder is a commercially available product, which can simplify the structural design of the equipment and reduce the production cost of the equipment.

[0053] As Figure 3 shown, the inner wall ultrasonic roller device 7 includes an inner wall radial groove base 701, inner wall roller seats 702 symmetrically and slidably arranged at both ends inside the inner wall radial groove base 701, and inner wall rollers 703 rotatably arranged at the outer ends of the inner wall roller seats 702 and with their axes vertically arranged. It also includes a horizontal two-way positioning mechanism 704 fixedly arranged on the outer wall of the inner wall radial groove base 701, and the two inner wall roller seats 702 are respectively fixedly connected to the two side positioning output ends of the horizontal two-way positioning mechanism 704. Specifically, horizontal first radial guide grooves are respectively formed on the inner surfaces of the upper and lower walls of the inner wall radial groove base 701, and the upper and lower ends of the inner wall roller seats 702 are respectively slidably embedded in the first radial guide grooves, so that the inner wall roller seats 702 can horizontally move inside the inner wall radial groove base 701, and the radial position of the inner wall roller 703 thereon can be adjusted by telescoping. Since the two inner wall rollers 703 at both ends need to respectively perform the same roll strengthening on both ends of the inner wall of the tubular part 100 at the same time, in this embodiment, the vertical central plane of the inner wall radial groove base 701 is set to coincide with the axis of the rotating base 4, the two inner wall roller seats 702 are symmetrically arranged left and right inside the inner wall radial groove base 701, and the two inner wall roller seats 702 are driven by the horizontal two-way positioning mechanism 704 to move synchronously towards or away from each other, so as to keep the axes of the two inner wall rollers 703 symmetrically distributed on both sides of the axis of the rotating base 4.

[0054] In this embodiment, the horizontal two-way positioning mechanism 704 includes a fixedly arranged first driving motor 7041, a horizontally rotatable two-way screw 7042, and first nut blocks 7043 threadedly connected to both ends of the two-way screw 7042. One end of the first nut block 7043 penetrates the inner wall radial groove seat 701 and is fixedly connected to the inner wall roller seat 702. The output shaft end of the first driving motor 7041 is in transmission connection with the middle of the two-way screw 7042 through a gear pair 7044. Specifically, the first driving motor 7041 is a servo motor and is fixedly installed on the inner wall radial groove seat 701 through a motor mounting seat. Its output shaft end is fixedly connected with a driving gear; the spiral directions of the threaded sections at both ends of the two-way screw 7042 are opposite, and both ends are rotatably arranged on the side of the inner wall radial groove seat 701 through bearing seats. A driven gear is fixedly sleeved on the outer side of the middle section, and the driven gear is in meshing transmission with the driving gear. By driving the two-way screw 7042 to rotate through the first driving motor 7041, the two first nut blocks 7043 and the inner wall roller seats 702 fixedly connected thereto are driven to move synchronously towards or away from each other through the threaded transmission between the two-way screw 7042 and the first nut blocks 7043, so as to realize the feeding of the two inner wall rollers 703 in the inner diameter direction of the cylindrical part 100. A first waist-shaped hole is formed in the side wall of the inner wall radial groove seat 701, and the first nut block 7043 is located in the first waist-shaped hole. A travel control switch (not shown in the figure) is further arranged on the side surface of the inner wall radial groove seat 701 on one side of the first waist-shaped hole for controlling the travel of the first nut block 7043.

[0055] As Figure 4 shown, an ultrasonic vibration device 10 is further arranged on the inner wall radial groove seat. The ultrasonic vibration device 10 includes two groups of ultrasonic vibrators, which are respectively arranged on the vertical side surfaces of the inner wall roller seat 702 far away from the inner wall roller 703 and the adjacent vertical side surfaces. In this way, independent ultrasonic vibrators are arranged on the inner wall roller seat 702 along the radial and tangential directions of the cylindrical part 100 to coordinately realize two-dimensional ultrasonic vibration of the required waveform. Under two-dimensional ultrasonic vibration, it is convenient to complete radial loading of the roller before roll pressing strengthening to bite into the inner wall of the cylindrical part 100, and then the cylindrical part 100 rotates at a constant speed to drive the roller to rotate passively, realizing continuous biting and roll pressing strengthening.

[0056] The inner wall ultrasonic roller device 7 highly integrates functions such as rollers, ultrasonic vibration devices, and two-way feeding, realizing the overall simplification of the equipment, and there are more possibilities for the application range and process design. Especially for additively manufactured cylindrical parts, gradient strengthening and toughening of the thick-wall integral structure are realized, and the quality and efficiency of strengthening and toughening are greatly improved by means of ultrasonic vibration.

[0057] Two groups of outer wall ultrasonic roller devices 8 are symmetrically arranged on both ends of the inner wall ultrasonic roller device 7. As Figure 5As shown, each group of outer wall ultrasonic roller devices 8 includes an outer wall radial groove seat 801, an outer wall roller seat 802 slidably disposed within the outer wall radial groove seat 801, an outer wall roller 803 rotatably disposed at the end of the outer wall roller seat 802 and configured to be relatively assembled with the inner wall roller 703, and further includes a horizontal positioning mechanism 804 fixedly disposed on the outer wall of the outer wall radial groove seat 801. Specifically, similar to the structure in the inner wall ultrasonic roller device 7, second radial guide grooves are respectively formed on the inner surfaces of the upper and lower walls of the outer wall radial groove seat 801, and the upper and lower ends of the outer wall roller seat 802 are respectively slidably inserted into the second radial guide grooves, such that the outer wall roller seat 802 can horizontally move within the outer wall radial groove seat 801, and the radial position of the outer wall roller 803 thereon can be adjusted by expansion and contraction. In this embodiment, the axes of the inner wall roller 703 and the outer wall roller 803 are located in the same vertical plane, and the rotating shaft of the rotating base 4 is located in this vertical plane. Thus, after the inner wall roller 703 and the outer wall roller 803 on the same side are paired and act, the side wall of the cylindrical member 100 on one side can be clamped and roll-pressed, and the roll-pressing positions on both sides are located at both ends of the diameter of the horizontal cross-section of the cylindrical member 100, so that the roll-pressing positions on both sides are symmetrically arranged on both sides of the cylindrical member 100, avoiding the problem of uneven force and deformation of the cylindrical member 100 caused by single-sided roll pressing.

[0058] As Figure 5 shown, in this embodiment, the horizontal positioning mechanism 804 includes a fixedly disposed second driving motor 8041, a rotatably disposed screw rod 8042, and a second nut block 8043 threadedly connected to the screw rod 8042. One end of the second nut block 8043 penetrates through the outer wall radial groove seat 801 and is fixedly connected to the outer wall roller seat 802, and the output shaft end of the second driving motor 8041 is drivingly connected to one end of the screw rod 8042. Specifically, the second driving motor 8041 also uses a servo motor and is fixedly installed on the outer wall radial groove seat 801 through a motor mounting seat. The two end portions of the screw rod 8042 are rotatably disposed on the side of the outer wall radial groove seat 801 through bearing seats, and the output shaft end of the second driving motor 8041 is drivingly connected to one end of the screw rod 8042. By driving the screw rod 8042 to rotate through the second driving motor 8041, the second nut block 8043 and the outer wall roller seat 802 fixedly connected thereto are driven to horizontally move through the threaded transmission between the screw rod 8042 and the second nut block 8043, thereby realizing the feeding of the outer wall roller 803 on the outer diameter of the cylindrical member 100. A second kidney-shaped hole is formed on the side wall of the outer wall radial groove seat 801, and the second nut block 8043 is located within the second kidney-shaped hole. A travel control switch (not shown in the figure) is further disposed on the side surface of the outer wall radial groove seat 801 and located on one side of the second kidney-shaped hole for controlling the travel of the second nut block 8043.

[0059] Similar to the inner wall radial groove seat 701, the outer wall radial groove seat 801 is also provided with an ultrasonic vibration device 10. The ultrasonic vibration device 10 also includes two sets of ultrasonic vibrators, which are respectively arranged on the vertical side surface of the outer wall roller seat 802 away from the outer wall roller 803 and on the vertical side surface adjacent thereto. The inner wall roller 703 and the outer wall roller 803 are both helical cylindrical gears with opposite spiral directions or are both cylindrical roller bodies. In this way, when the roller pair adopts symmetrically arranged helical cylindrical gears, after the roller pair clamps the side wall of the cylindrical member 100 and rolls, a cross tooth mark can be formed on the inner and outer surfaces of the side wall of the cylindrical member 100, making the rolling efficiency higher and alleviating the common problems of thinning and lengthening in the rolling process.

[0060] In order to facilitate the manufacture of components and improve the commonality between components, in this embodiment, the inner wall radial groove seat 701 of the inner wall ultrasonic roller device 7 is formed by relatively splicing two outer wall radial groove seats 801, and the inner wall roller seat 702 has the same structure as the outer wall roller seat 802. When the inner wall roller 703 and the outer wall roller 803 are both cylindrical roller bodies, the structures of the two are also the same.

[0061] The outer wall ultrasonic roller device 8 is connected to the guide column 3 on the corresponding side through the second vertical positioning mechanism 9, and the outer wall ultrasonic roller device 8 is fed and positioned in the axial direction of the cylindrical member 100 through the second vertical positioning mechanism 9. Figure 5 As shown, the second vertical positioning mechanism 9 includes a rack 903 fixedly arranged vertically on the side wall of the guide column 3 close to the rotating base 4, a third driving motor 901 fixedly installed on the top surface of the outer wall radial groove seat 801 through a motor mounting seat, and a lifting gear 902 fixedly installed on the output shaft end of the third driving motor 901 and meshing with the rack 903 for transmission. Among them, the third driving motor 901 also adopts a servo motor, which drives the lifting gear 902 to rotate, and realizes the overall lifting and positioning of the outer wall ultrasonic roller device 8 through the gear rack transmission. To this end, a through hole matching the outer diameter of the guide column 3 is opened at the tail of the outer wall radial groove seat 801, and the guide column 3 is located in the through hole to realize the vertical guidance of the outer wall ultrasonic roller device 8 on the guide column 3; a chord plane is set on the side wall of the guide column 3 close to the rotating base 4, so that a space is left between it and the inner wall of the through hole, so that the rack 903 is located in the space and does not interfere with the inner wall of the through hole.

[0062] The tubular part 100 after additive manufacturing or machining may have relatively large residual stresses, and stress relief annealing is required to reduce the internal stresses, thereby improving the stability of the rolling process. At the same time, according to the material properties, solution treatment and aging treatment can be implemented to optimize the matrix structure, obtain a uniform and stable performance basis, and provide ideal conditions for rolling strengthening. Before rolling, the surface of the workpiece needs to be thoroughly cleaned to remove grease, scale and dirt, ensuring full contact between the roller and the workpiece surface, which can be completed by ultrasonic cleaning, chemical cleaning or sandblasting. At the same time, a protective lubricant or solid lubricating film is coated on the surface of the tubular part 100 before rolling to reduce the friction coefficient during the rolling process, reduce surface damage and improve the processing quality.

[0063] The present invention also provides a surface tooth-shaped rolling strengthening process for an additive manufacturing tubular part, comprising the following steps:

[0064] S1. Fix the tubular part 100 on the rotating base 4 through the positioning assembly 5.

[0065] Before performing this step, it is necessary to ensure that both the inner wall ultrasonic roller device 7 and the outer wall ultrasonic roller device 8 are at the highest vertical position to facilitate the installation operation of the workpiece; at the same time, the inner wall roller seat 702 contracts to the innermost end of the inner wall radial groove seat 701, and the outer wall roller seat 802 contracts to the innermost end of the outer wall radial groove seat 801, so that the radial distance between the inner wall roller 703 and the outer wall roller 803 on the same side is large enough, so that after the tubular part 100 is installed and fixed, the roller pair can smoothly enter the bottom of the side wall of the tubular part 100.

[0066] After ensuring that the roller pair is at a safe height, place the tubular part 100 between the positioning inner core 501 and the positioning pressure ring 502. A good fit with the positioning inner core 501 ensures that the tubular part 100 is at the exact center position of the rotating base 4 and its axial verticality is within the error range, avoiding problems such as uneven large-area stress distribution and instability caused by workpiece tilt. Then, the side wall of the tubular part 100 is mutually pressed by the positioning wedge block 503 and the positioning inner core 501, and the clamping pressure at each place is kept consistent to prevent the workpiece from sliding due to uneven friction during the rotary machining process.

[0067] S2. The inner wall roller 703 and the outer wall roller 803 adopt helical cylindrical gears. The inner wall roller 703 and the outer wall roller 803 are initially positioned to the lowest position, and the initial position of the inner wall roller 703 and the outer wall roller 803 is adjusted so that the radial distance between each roller and the cylinder wall is the same.

[0068] Due to inevitable minor dimensional deviations in the additive - manufactured cylindrical part 100, the rollers need to be positioned before the roll - pressing strengthening process. After each roller synchronously axially feeds to the bottom of the cylindrical part 100, the radial distances between each roller and the inner and outer cylindrical walls of the cylindrical part 100 are uniformly adjusted and all maintained at 15 mm to ensure the same feed distance for the cylindrical walls.

[0069] S3. Set the workpiece rotation speed, the radial and axial feed parameters of the rollers, and the ultrasonic vibration parameters.

[0070] For the 2 - series aluminum alloy, set the vibration frequency of the ultrasonic vibration device 10 to 20 kHz, the amplitude to 15 μm, and the power to 1000 W. Turn on each ultrasonic vibration device 10 before the roller feed to achieve two - dimensional vibration. Set the radial feed speed of the rollers to 1 mm / s and the workpiece rotation speed to 0.628 rad / s, that is, the cylindrical part 100 rotates one week in 10 s, and the corresponding rotation angle is 2π. During the rotation period of the cylindrical part 100 (i.e., 10 s), the axial feed distance is equal to or less than the axial thickness of the roller to ensure that the tooth marks of the roll - pressing completely cover the cylindrical wall.

[0071] S4. Start the ultrasonic vibration device 10. The two groups of inner - wall rollers 703 and outer - wall rollers 803 synchronously radially feed towards the cylindrical wall at a preset feed speed to a preset distance, so that the inner - wall rollers 703 bite into the inner cylindrical wall and the outer - wall rollers 803 bite into the outer cylindrical wall.

[0072] After the ultrasonic vibration device 10 is started, the horizontal two - way positioning mechanism 704 drives the two inner - wall rollers 703 to gradually approach the two - side inner walls of the cylindrical part 100 synchronously. Synchronously, the horizontal positioning mechanisms 804 on both sides respectively drive the outer - wall rollers 803 to gradually approach the two - side outer walls of the cylindrical part 100 until each roller radially feeds towards the cylindrical wall to the set distance, and then the horizontal two - way positioning mechanism 704 and the horizontal positioning mechanism 804 both stop working. For the gradient structure strengthening of the rocket cabin section, feed the outer - circular side wall of the helical cylindrical gear to 15% of the wall thickness.

[0073] S5. The rotating base 4 drives the cylindrical part 100 to rotate uniformly at a preset speed. After a preset time, the cylindrical part 100 rotates one week, and each roller synchronously axially feeds upward at a uniform speed with the axial width of a single roller. During the uniform rotation of the cylindrical part 100, the inner - wall rollers 703 and outer - wall rollers 803 on the same side rotate passively, so as to cooperatively roll - press the inner and outer surfaces of the cylindrical part 100, realizing continuous biting and roll - pressing strengthening. The double - helix cross - tracks on both sides can form cross - shaped tooth marks on the inner and outer surfaces of the side wall of the cylindrical part 100, making the roll - pressing efficiency higher and at the same time alleviating the common problems of thinning and drawing - out during the roll - pressing process.

[0074] After the cylindrical part 100 rotates one full circle, the bottom circle of the side wall is completely covered and roll-pressed. At this time, the first vertical positioning mechanism 6 drives the inner wall ultrasonic roller device 7 to start axially rising at a preset speed uniformly, and the second vertical positioning mechanism 9 drives the outer wall ultrasonic roller device 8 to axially rise synchronously with the inner wall ultrasonic roller device 7. Every time the cylindrical part 100 rotates one full circle, the two roller devices axially move a preset axial distance to ensure that the tooth marks completely cover the barrel wall. Under the combined action of the rotation of the cylindrical part 100 and the axial linear movement of the rollers, double-helix trajectory strengthening of the barrel wall is achieved. Until the top of each roller exceeds the uppermost end of the cylindrical part 100 and the last roll-pressing is completed, the horizontal two-way positioning mechanism 704 drives the two inner wall rollers 703 to gradually move away from the inner walls on both sides of the cylindrical part 100 synchronously. Synchronously, the horizontal positioning mechanisms 804 on both sides respectively drive the outer wall rollers 803 to gradually move away from the outer walls on both sides of the cylindrical part 100 to complete the radial reset of each roller, and then the equipment pauses.

[0075] S6. Replace each roller with a cylindrical roller body of the same diameter and position it at the lowest position, and repeat steps S4 to S5 to finish rolling flat the barrel wall of the cylindrical part. Due to the innovative cross indentation, when rolling flat, change the radial feed distance of the roller towards the wall thickness to 8% of the wall thickness. The radial feed distance of the cylindrical roller body is less than that of the helical cylindrical gear in the same pass.

[0076] S7. Gradually reduce the radial feed distance of each roller biting into the wall thickness by a preset reduction amount, and repeat steps S3 to 6 for a preset number of times to complete the gradient structure strengthening and toughening of the barrel wall. In this embodiment, the radial feed distance of the next pass is 80% of that of the previous pass, that is, the reduction amount of the radial feed distance for each pass is 20%.

[0077] S8. Remove the cylindrical part 100 and perform heat treatment optimization and surface repair.

[0078] Move each positioning wedge 503 radially outwards to release the clamping of the cylindrical part 100. At this time, each roller that has completed roll-pressing strengthening is at the highest position, and the cylindrical part 100 can be removed from the rotating base 4. Then, thoroughly clean the surface by methods such as ultrasonic cleaning, chemical cleaning or high-pressure water rinsing to ensure the effect of subsequent processing. After appropriate heat treatment optimization and surface repair, machine-process to remove the excess waste material in the pressing and positioning part.

[0079] In this embodiment, the process simulation function of Simufact Forming software is used to simulate one pass of the surface tooth-shaped roll strengthening and toughening process of the additive manufacturing cylindrical part.

[0080] Pre-treatment of roller teeth: The driving program of the mold uses a table-driven motor to control its movement speed and trajectory. The general idea is that the roller first feeds radially, then the blank starts to rotate, and then the roller feeds axially. At the same time, the spiral strengthening trajectory and depth are designed through the rotational speed of the lower bottom die (corresponding to the aforementioned rotating base 4), the feeding speed, direction, and time parameters of the roller.

[0081] It mainly includes: First, the movement of the lower bottom die and the blank (the lower bottom die drives the cylindrical blank to rotate at a speed of 0.628 rad / s, that is, one revolution in 10 s through a motor-controlled uniform rotation. At the same time, the lower bottom die and the blank are in viscous contact to ensure that there is no excessive relative sliding between the lower bottom die and the blank (the friction coefficient uses a shear-type friction with a ratio of 0.4).

[0082] Second, the radial movement of the helical rollers (corresponding to the inner wall roller 703 and the outer wall roller 803 using helical cylindrical gears mentioned above): When the two pairs of helical rollers feed radially towards the wall thickness direction, two helical rollers will move synchronously in the X direction, and the other two helical rollers will move synchronously in the -X direction. Therefore, in this simulation, a hydraulic press with two mirror movement parameters can be used for the four helical rollers. The model reduces the blank wall thickness to 15 mm in proportion, and the helical rollers are fed 2 mm towards the blank thickness direction by controlling the X-direction speed and movement time.

[0083] Third, the axial movement of the helical rollers: The rotational speed of the blank and the axial movement of the helical rollers determine the trajectory of the double helix. Considering the thickness of the roller itself and the height of the cylinder wall, through multiple attempts, the axial movement speed of the helical rollers is set to 2 mm / s. The double helix trajectory under this parameter can completely cover the entire cylinder wall surface, and avoids the repeated coverage of the next layer of helix on the previous layer, making the overall strengthening effect more uniform.

[0084] Fourth, temperature and movement constraint parameters: The temperature is room temperature for forming, and the deformation naturally raises the temperature; the roller is set to rotate passively, the rotation axis is fixed, and parameters such as the rotation direction, friction, movement constraints, and torque spring are set; the bottom die is set to rotate actively and is adhesively contacted with the blank to drive the rotation.

[0085] (2) Results of post-treatment of roller teeth: It can be analyzed from Figure 7 and Figure 8 that the strengthened tooth marks on the cylinder wall are improved, and the strain distribution between each tooth mark and between the tooth marks is uniform. The plastic strain gradient effect of the overall wall thickness is obvious, and there is no obvious deformation instability phenomenon. After the first pass of roller teeth is completed, its gradient-type cumulative plastic strain meets the requirements; and there is no obvious thinning and elongation of the overall cylinder wall, which is convenient for subsequent machining and improves the material utilization rate. As Figure 9As shown, seven equivalent plastic strain reference points are evenly taken along the radial direction at the cylinder wall to obtain the radial equivalent plastic strain curve of the entire cylinder wall. It can be seen from the curve that the strains at both ends of the curve are obvious, and the gradient decreases in the middle stage, fully demonstrating the gradient strengthening effect of this process.

[0086] (3)Pre-treatment before roller flattening: Change the radial feed distance of the wall thickness of the roller flattening wheel (corresponding to the inner wall roller 703 and the outer wall roller 803 with a cylindrical roller body mentioned above) to 1 mm, and the other parameters are the same as those in the previous roller tooth process.

[0087] (4)Results of post-treatment after roller flattening: As Figure 10 shown is the distribution diagram of the radial cumulative plastic strain after the roller flattening is completed. Eight points are selected radially on the cylinder wall to obtain its cumulative plastic strain curve. It can be clearly seen that the distribution of its cumulative plastic strain shows a trend of being low in the middle and gradually increasing at both ends, fully demonstrating the gradient tissue strengthening effect of this process, and the strengthening effect of the outer wall part with more severe service conditions is better. As Figure 11 shown is the schematic diagram of the thickness change of the cylinder wall. It can be seen that only a very small part at the upper end has excessive thinning under this process. When measuring the height of the cylindrical part and the thicknesses at multiple positions, it is found that except for the top part, the maximum thinning rate among the three scattered positions measured is 0.8%, and the overall height has increased by 1.2%, which is within the reasonable range of the machining allowance.

[0088] The technical features of the above-described embodiments can be combined arbitrarily. For the sake of brevity of description, not all possible combinations of the technical features in the above embodiments are described. However, as long as there is no contradiction in the combination of these technical features, it should be considered as the scope described in this specification.

[0089] The above is only the embodiments of the present invention, and thus do not limit the patent scope of the present invention. Any equivalent structure or equivalent process transformation made by using the content of the specification and drawings of the present invention, or directly or indirectly applied in other related technical fields, shall be equally included in the patent protection scope of the present invention.

Claims

1. An additive manufacturing cylindrical part surface toothed roller toughening equipment, comprising a lower die base, an upper die base and a plurality of guide columns, characterized in that: A rotating base is arranged in the lower die seat, a positioning assembly is arranged on the rotating base, a first vertical positioning mechanism is arranged on the bottom surface of the upper die seat, an inner wall ultrasonic roller device is fixedly connected to the bottom positioning end of the first vertical positioning mechanism, and the inner wall ultrasonic roller device comprises an inner wall radial groove seat, an inner wall roller seat symmetrically slidably arranged at both ends of the inner wall radial groove seat, and an inner wall roller rotatably arranged at the outer end of the inner wall roller seat and arranged vertically with its axis; Two groups of outer wall ultrasonic roller devices are symmetrically arranged at both ends of the inner wall ultrasonic roller device, and each group of outer wall ultrasonic roller devices includes an outer wall radial groove seat, an outer wall roller seat slidably arranged in the outer wall radial groove seat, and an outer wall roller rotatably arranged at the end of the outer wall roller seat and arranged to be assembled with the inner wall roller. The outer wall ultrasonic roller device is connected to the guide column on the corresponding side through a second vertical positioning mechanism, and the inner wall roller and the outer wall roller are both helical cylindrical gears with opposite spiral directions. Ultrasonic vibration devices are also respectively arranged on the inner wall radial groove seat and the outer wall radial groove seat.

2. The surface toothed roller toughening equipment for additively manufactured cylindrical parts according to claim 1, characterized in that: The inner wall ultrasonic roller device also includes a horizontal bidirectional positioning mechanism fixedly arranged on the outer wall of the inner wall radial groove seat, and two inner wall roller seats are respectively fixedly connected to the positioning output ends on both sides of the horizontal bidirectional positioning mechanism, and the two inner wall roller seats move synchronously toward or away from each other.

3. The surface toothed roller toughening equipment for additively manufactured cylindrical parts according to claim 2, characterized in that: The horizontal bidirectional positioning mechanism includes a first fixed driving motor, a bidirectional screw rod arranged to rotate horizontally, and first nut blocks respectively threadedly connected to the two ends of the bidirectional screw rod, one end of the first nut block passes through the inner wall radial groove seat and is fixedly connected to the inner wall roller seat, and the output shaft end of the first driving motor is connected to the middle part of the bidirectional screw rod through a gear pair.

4. The surface toothed roller toughening equipment for additively manufactured cylindrical parts according to claim 3, characterized in that: The inner surfaces of the upper and lower walls of the inner wall radial groove seat are respectively provided with first radial guide grooves, and the upper and lower ends of the inner wall roller seat are respectively slidably embedded in the first radial guide grooves.

5. The surface toothed roller toughening equipment for additively manufactured cylindrical parts according to claim 1, characterized in that: The outer wall ultrasonic roller device also includes a horizontal positioning mechanism fixedly arranged on the outer wall of the outer wall radial groove seat, the horizontal positioning mechanism includes a fixedly arranged second drive motor, a rotatably arranged screw rod, and a second nut block threadedly connected to the screw rod, one end of the second nut block passes through the outer wall radial groove seat and is fixedly connected to the outer wall roller seat, and the output shaft end of the second drive motor is transmission-connected to one end of the screw rod.

6. The surface toothed roller toughening equipment for additively manufactured cylindrical parts according to claim 5, characterized in that: Second radial guide grooves are respectively provided on the inner surfaces of the upper and lower walls of the outer wall radial groove seat, and the upper and lower ends of the outer wall roller seat are respectively slidably embedded in the second radial guide grooves.

7. The surface toothed roller toughening equipment for additively manufactured cylindrical parts according to any one of claims 1 to 6, characterized in that: The ultrasonic vibration device comprises two groups of ultrasonic vibrators, which are respectively arranged on a vertical side surface of the inner wall roller seat away from the inner wall roller / the outer wall roller seat away from the outer wall roller and on a vertical side surface adjacent thereto.

8. The toothed roller toughening equipment for the surface of an additively manufactured cylindrical part according to any one of claims 1 to 6, characterized in that: The axes of the inner wall roller and the outer wall roller are located in the same vertical plane, and the rotating shaft of the rotating base is located in the vertical plane.

9. A process for strengthening and toughening the surface of a cylindrical part by toothed roller pressing in additive manufacturing, applied to the equipment for strengthening and toughening the surface of a cylindrical part by toothed roller pressing in additive manufacturing as claimed in any one of claims 1 to 8, characterized in that: The following steps are involved: S1, the cylindrical part is fixed on the rotating base; S2, the inner wall roller and the outer wall roller are initially positioned to the lowest position using helical cylindrical gears; S3, setting the workpiece rotation speed, roller radial feed and axial feed parameters and ultrasonic vibration parameters; S4, start the ultrasonic vibration device, and the two sets of rollers are synchronously fed radially toward the cylinder wall until the rollers on both sides bite into the cylinder wall; S5. The rotating base drives the cylindrical member to rotate at a preset uniform speed. After the cylindrical member rotates one circle, each roller synchronously feeds upward by the axial width of a single roller until each roller completely rolls the uppermost end of the cylindrical member, and the equipment is paused. S6, each roller is replaced with a cylindrical roller of the same diameter and positioned to the lowest position, and steps S4 to S5 are repeated to complete the rolling of the cylindrical wall of the cylindrical part; S7, gradually reducing the radial feed distance of each roller biting into the wall thickness by a preset reduction amount, repeating steps S3 to step 6 for a preset number of times, and completing the gradient structure toughening of the barrel wall; S8. Remove the cylindrical part and perform heat treatment optimization and surface repair.

10. The process for toughening the surface of a cylindrical part by toothed rolling in additive manufacturing according to claim 9, characterized in that: The radial feed distance of the cylindrical roller body is smaller than the radial feed distance of the helical cylindrical gear in the same pass.

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