An additive manufacturing lightweight tool based on external structure topology optimization and a design method thereof

Abstract

The application discloses a kind of additive manufacturing light-weight cutter based on external structure topology optimization and its design method, belong to milling cutter technical field.The cutter includes tool body, blade and fastener, tool body exterior is formed with chip flute and turbulence generation area by topology optimization, chip flute is located at blade mounting surface back, turbulence generation area is located at blade mounting surface front side and is communicated with the cooling liquid flow passage in tool body interior.The application scheme is by topology optimization to tool body external structure, avoids the problem of residual powder residue caused by complex internal cavity structure, realizes the light-weight effect that tool body volume is reduced by 47.89%, simultaneously using chip flute guides chip to smoothly discharge, using turbulence generation area makes cooling liquid produce turbulence to strengthen heat exchange, significantly improves the dynamic balance performance, chip removal performance and cooling efficiency of cutter.

Description

Technical Field

[0001] This application belongs to the field of milling tool technology, specifically involving a lightweight additive manufacturing tool based on external structure topology optimization and its design method. Background Technology

[0002] Milling cutters are hailed as the "teeth" of manufacturing, their performance directly impacting product machining quality and production efficiency. With the development of high-speed milling technology, higher demands are placed on the lightweighting, cooling efficiency, and chip removal performance of cutting tools. The emergence of additive manufacturing technology has brought new possibilities to tool design and manufacturing, eliminating the machinability limitations of traditional subtractive manufacturing and enabling the integrated molding of complex tool structures. Currently, research has applied additive manufacturing and topology optimization techniques to the cutting tool field. For example, patent document CN117943600A discloses an additively manufactured internal flow channel face milling cutter based on topology optimization. By optimizing the internal structure of the cutter head to form a double-helix support structure, it achieves lightweighting of the cutter body while incorporating main and branch channels within the cutter head for cooling the cutting milling area. Patent document CN109352056A discloses a face milling cutter with a self-cooling and lubricating structure. It uses 3D printing technology to integrally form the main flow channel and the secondary flow channel inside the cutter holder and the cutter body, and sets a temporary storage area for cooling and lubricating fluid to improve the uniformity of coolant distribution.

[0003] However, existing additive manufacturing-based tool designs still have significant limitations. Current research mainly focuses on the topology optimization of the tool's internal lattice structure or internal flow channels. While such designs can reduce tool mass to some extent, they also introduce new technical problems.

[0004] First, the complex internal cavity structure easily leaves behind metal powder during additive manufacturing. This residue is difficult to clean and directly affects the dynamic balance of the cutting tool, causing vibration during high-speed rotation and impacting machining quality and spindle life. Second, existing topology optimizations rarely address the chip grooves and coolant contact surfaces outside the cutting tool. This leads to obstructed chip removal during high-speed milling, causing chip accumulation and scratching of the machined surface. Simultaneously, the milling fluid has difficulty penetrating the core high-temperature zone, limiting cooling efficiency and affecting insert life and surface finish. Third, excessive pursuit of internal lightweighting may result in insufficient torsional strength of the cutting tool during milling, failing to meet reliability requirements under high-volume milling conditions. Regarding the design of the chip space and coolant flow channels outside the cutting tool, while existing technologies include adding cooling holes within the chip grooves, as shown in patent document CN105436589B, this only achieves cooling through localized openings and does not systematically optimize the external structure from the perspective of the overall tool body configuration. This makes it difficult to simultaneously improve lightweighting, chip removal smoothness, and cooling efficiency.

[0005] To address the technical problems of difficult internal powder removal, insufficient external performance optimization, and difficulty in balancing lightweight and strength in the existing technologies, this application provides a lightweight additive manufacturing tool and its design method based on external structure topology optimization. Summary of the Invention

[0006] To address the technical problems mentioned in the background section regarding existing technologies: firstly, the complex internal cavity structure leads to difficulty in cleaning residual powder and affects dynamic balance; secondly, existing topology optimizations mainly focus on the internal structure, with insufficient optimization of the chip grooves and coolant contact surfaces on the outside of the tool, resulting in obstructed chip removal and difficulty in the penetration of milling fluid into the core high-temperature area during high-speed milling; and thirdly, excessive pursuit of internal lightweighting may lead to insufficient torsional strength. In other words, existing technologies suffer from difficulties in cleaning internal residual powder, insufficient external performance optimization, and the difficulty in balancing lightweighting and strength. This application provides a lightweight additive manufacturing tool based on external structure topology optimization. This tool optimizes the topology of its external main body structure, forming chip grooves and turbulence generation zones on the back and front sides of the insert mounting surface, respectively, and connecting the turbulence generation zone to the internal coolant flow channels. This design avoids the formation of complex internal cavity structures, eliminating the impact of residual chips on dynamic balance. Furthermore, it utilizes externally optimized chip grooves to guide smooth chip removal and generates coolant turbulence outside the tool body using a turbulence generation zone, enhancing heat transfer. Thus, while ensuring the structural strength of the tool, it comprehensively improves the tool's lightweight level, chip removal performance, and cooling efficiency. The technical solution is as follows: This additive manufacturing lightweight tool based on external structural topology optimization includes a tool body, an insert, and fasteners. The tool body has an insert mounting surface along its circumference, and an insert mounting notch on the mounting surface. The insert is mounted to the insert mounting notch using fasteners. The tool body has a lightweight main body configuration, and its exterior is provided with a turbulence generation zone and a chip-receiving groove. The turbulence generation zone is located on the front side of the insert mounting surface and is an arc-shaped structure recessed into the tool body. The chip-receiving groove is located on the back side of the insert mounting surface and is a recessed groove structure recessed into the tool body. The turbulence generation zone is connected to the coolant flow channel inside the tool body.

[0007] In some embodiments, the chip groove is a groove structure, and the boundary of the groove structure is transitioned by an arc surface.

[0008] In some embodiments, along the axial direction of the cutter body, the cutter body sequentially includes a base and a mounting base; the mounting base is provided with the blade mounting surface; along the axial direction of the cutter body, the turbulence generation zone extends from the top of the base to the top of the mounting base; wherein, from the top of the base to the bottom of the blade mounting surface, the angle between the tangent of the turbulence generation zone and the horizontal is α1, and the rate of change of α1 gradually decreases; from the bottom of the blade mounting surface to the top of the cutter body, the angle between the tangent of the turbulence generation zone and the horizontal is α2, and the rate of change of α2 gradually increases, so that the turbulence generation zone forms a streamlined arc surface structure with a central concave shape.

[0009] In some embodiments, the turbulence generation zone is pear-shaped, narrow at the top and bottom and wide in the middle.

[0010] In some embodiments, the width ratio of the top, middle and bottom sides of the pear-shaped structure is 0.4:0.85:0.4.

[0011] In some embodiments, along the axial direction of the cutter body, the coolant channel extends from the lower part of the mounting base to the top of the cutter body, and the upper part of the turbulence generation zone is connected to the coolant channel through a liquid hole.

[0012] In some embodiments, a mounting through hole is provided in the middle of the blade body, and the mounting through hole is provided along the axial direction of the blade body; the coolant channel does not penetrate the top of the blade body, and the coolant channel extends to the mounting through hole and the outer wall of the blade body on both sides in the width direction, respectively, and the coolant channel does not penetrate to the mounting through hole and the outer wall of the blade body, so that the coolant channel forms a blind groove structure.

[0013] In some embodiments, the blade is quasi-cubic prism, and the blade has a blade chip groove at its center; the blade chip groove of the blade is provided with a mounting hole for mounting the fastener, and the blade mounting surface is provided with a mounting hole for mounting the fastener.

[0014] In some embodiments, the blade body has blade mounting surfaces distributed at equal angles along its circumference.

[0015] In some embodiments, a cylindrical mounting through hole is provided in the middle of the blade body, and the mounting through hole is arranged along the axial direction of the blade body.

[0016] In some embodiments, the base material of the blade is WC and Co, and the surface of the blade has a coating, which is a single layer of TiB.

[0017] In some embodiments, the diameter of the blade body is 45mm, the diameter of the blade body after the blade is installed is 50mm, the height of the blade body is 40.6mm, and the diameter of the shank mating hole of the blade body is 22mm.

[0018] In some embodiments, the material of the blade body is 42CrMo, with a tensile strength of 1080MPa and a yield strength of 930MPa.

[0019] In some embodiments, the volume of the blade body is 22557.376 mm². 3 .

[0020] In some embodiments, the dynamic balance accuracy grade of the cutter body is G5.0 at a rotational speed of 8000 r / min and G6.3 at a rotational speed of 10000 r / min.

[0021] This application also provides a design method for lightweight additive manufacturing tools based on external structure topology optimization as described above, which includes the following steps: S1: Perform static analysis on the standard tool body to determine the non-optimizable and optimizable stress concentration areas on the tool body; S2: Perform topology optimization on the optimizable region to form a turbulence generation zone and chip groove outside the cutter body; S3: The structure of the turbulence generation zone is optimized using CFD (Computational Fluid Dynamics) technology; S4: The optimized blade body is integrally formed using additive manufacturing technology.

[0022] Compared with the prior art, the solution of this application has the following advantages: This application provides a lightweight additive manufacturing tool based on external structural topology optimization. The tool optimizes the topology of its external main structure, forming chip grooves and turbulence generation zones on the back and front sides of the insert mounting surface, respectively, and connecting the turbulence generation zone to the internal coolant flow channels. This design avoids the formation of complex internal cavity structures, eliminating the impact of residual powder on dynamic balance. Furthermore, the optimized chip grooves guide smooth chip removal, while the turbulence generation zone generates coolant turbulence outside the tool body, enhancing heat transfer. Thus, while maintaining the tool's structural strength, it comprehensively improves the tool's lightweight level, chip removal performance, and cooling efficiency.

[0023] Other features and beneficial effects of this application will be set forth in the following description and will be apparent in part from the description or may be learned by practicing the application. The objectives and other beneficial effects of this application may be realized and obtained by means of the structures particularly pointed out in the description, claims and drawings. Attached Figure Description

[0024] To more clearly illustrate the technical solutions in the embodiments of this application or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of this application. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort. Unless otherwise specified, the positional relationships in the drawings described below are based on the direction in which the components are drawn in the figures.

[0025] Figure 1 This is a schematic diagram of the structure of an existing standard face milling cutter; Figure 2 This is a side view of a standard face milling cutter. Figure 3 This is a schematic diagram of the overall structure of the additive manufacturing lightweight tool based on external structure topology optimization in Embodiment 1 of this application. Figure 4 This is a three-dimensional structural diagram of the blade body structure in Embodiment 1 of this application; Figure 5 This is a partial structural diagram of the external turbulence generation zone and chip groove of the cutter body in Embodiment 1 of this application; Figure 6 This is a side view of the blade body structure in Embodiment 1 of this application; Figure 7 This is a side sectional view of the blade structure in Embodiment 1 of this application; Figure 8 This is a schematic diagram of the blade's external structure in Embodiment 1 of this application. Figure 1 ; Figure 9 This is a schematic diagram of the blade's external structure in Embodiment 1 of this application. Figure 2 ; Figure 10 This is a schematic diagram of the turbulence effect from different angles based on CFD technology in the scheme of this application; Figure 11 This is a three-dimensional structural diagram of the blade in Embodiment 1 of this application; Figure 12 This is a partial enlarged view of the turbulence generation zone of the cutter body in Embodiment 1 of this application.

[0026] Figure label: 31. Blade; 32. Fastener; 33. Blade body; 331. Base; 332. Mounting base; 3321. Blade mounting notch; 333. Coolant flow channel; 41. Chip groove; 411. Internal chip groove; 412. External bottom chip groove; 42. Turbulence generation zone; 311. Blade chip groove body. Detailed Implementation

[0027] To make the objectives, technical solutions, and advantages of the embodiments of this application clearer, the technical solutions of the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this application, not all embodiments. The technical features designed in the different implementations of this application described below can be combined with each other as long as they do not conflict with each other. All other embodiments obtained by those skilled in the art based on the embodiments of this application without creative effort are within the scope of protection of this application.

[0028] In the description of this application, it should be noted that all terms used in this application (including technical and scientific terms) have the same meaning as commonly understood by one of ordinary skill in the art to which this application pertains, and should not be construed as limiting this application; it should be further understood that the terms used in this application should be understood to have the same meaning as those in the context of this specification and the relevant field, and should not be understood in an idealized or overly formal sense, except as expressly defined in this application.

[0029] like Figures 3 to 12 As shown, Embodiment 1 of this application provides a lightweight additive manufacturing tool based on external structure topology optimization, the specific solution of which is as follows: Example 1 This embodiment provides a lightweight additive manufacturing tool based on external structure topology optimization, specifically a face milling cutter. For example... Figure 3-7 , Figure 11 As shown, the cutting tool includes a tool body 33, a blade 31, and a fastener 32, wherein the fastener 32 is a fastening bolt.

[0030] I. Blade Body 33 Structure The cutter body 33 is made of 42CrMo, and its chemical composition is shown in Table 1. The cutter body 33 has four uniformly arranged blade 31 mounting surfaces along its circumference. Each blade 31 mounting surface has a blade mounting notch 3321, and the blade 31 is fixed to the blade mounting notch 3321 by fasteners 32. The cutter body 33 has a lightweight main body configuration, which is obtained through topology optimization of the external structure.

[0031] Table 1. Composition of 42CrMo (wt.%)

[0032] The cutter body 33 includes a base 331 and a mounting base 332 along the axial direction. The mounting base 332 has a mounting surface for the blade 31. A cylindrical mounting through hole is provided in the middle of the cutter body 33, which extends axially for mating with the tool holder. The diameter L of the cutter body 33 is 45mm, and the diameter is 50mm after the blade 31 is installed. The height H is 40.6mm, and the diameter of the mating hole between the tool holder and the cutter body 33 is 22mm.

[0033] II. Turbulence generation zone 42 and coolant flow channel 333 like Figure 4 , Figure 5 , Figure 7 As shown, a turbulence generating zone 42 is provided on the exterior of the cutter body 33. This turbulence generating zone 42 is located on the front side of the mounting surface of the blade 31 and is a streamlined arc-shaped structure that is recessed into the cutter body 33 in the middle. Along the axial direction of the cutter body 33, the turbulence generating zone 42 extends from the top of the base 331 to the top of the mounting base 332. Wherein, as... Figure 12 As shown, from the top of the base 331 to the bottom of the blade 31 mounting surface, the angle between the tangent of the turbulence generation zone 42 and the horizontal is α1, and the rate of change of α1 gradually decreases; from the bottom of the blade 31 mounting surface to the top of the blade body 33, the angle between the tangent of the turbulence generation zone 42 and the horizontal is α2, and the rate of change of α2 gradually increases, so that the turbulence generation zone 42 forms a streamlined arc-shaped structure with a central concave depression. Furthermore, from a side view, the turbulence generation zone 42 is arc-shaped due to the concave arc surface, while from a front view, the turbulence generation zone 42 is pear-shaped, narrow at the top and bottom and wide in the middle. This pear-shaped shape is the optimal turbulence generation structure obtained through CFD technology optimization. See also... Figure 10 The external turbulence zone was structurally optimized using CFD technology. By adjusting the shape of the channel outlet (turbulence generation zone 42 structure), the optimal coolant turbulence effect was obtained, ultimately determining the turbulence zone to be a pear-shaped structure that is narrow at the top and bottom and wide in the middle. Specifically, in this embodiment, the width ratio of the top, middle, and bottom edges of the pear-shaped structure is 0.4:0.85:0.4.

[0034] The cutter body 33 has a coolant channel 333 inside. Along the axial direction of the cutter body 33, the coolant channel 333 extends from the lower part of the mounting base 332 to the top of the cutter body 33, and the coolant channel 333 is connected to the turbulence generation zone 42. The coolant channel 333 does not penetrate the top of the cutter body 33. Between the mounting through hole in the middle of the cutter body 33 and the outer wall of the cutter body 33, the coolant channel 333 extends to the mounting through hole and the outer wall of the cutter body 33 on both sides in the width direction, but does not penetrate either, that is, the coolant channel 333 is a blind groove structure. When the milling fluid enters the coolant channel 333 from the internal cooling system and flows through the turbulence generation zone 42, due to the guidance of the pear-shaped structure of the turbulence generation zone 42, a turbulent and irregular turbulent field is generated, which greatly improves the heat exchange efficiency between the coolant, the tool and the chips.

[0035] III. Chip Groove 41 like Figure 4 , Figure 5 As shown, a chip-receiving groove 41 is also provided on the outside of the blade body 33. This groove 41 is located on the back of the mounting surface of the blade 31 and is a recessed structure that extends inwards from the blade body 33. The chip-receiving groove 41 is a recessed structure, and the boundary of the recessed structure is transitioned by an arc surface. Figure 5-6 As shown in this specific embodiment, the chip-receiving groove 41 extends from the top of the back of the blade 31 mounting surface to the top of the base 331. Along the axial direction of the blade body 33, the chip-receiving groove 41 includes an inner chip-receiving groove 411 and an outer bottom chip-receiving groove 412. The inner chip-receiving groove 411 is an S-shaped structure with a height of 24.7 mm and a depth of 7 mm. The outer bottom chip-receiving groove 412 is integrally connected to the side of the turbulence generation zone 42. The wall thickness D of the chip-receiving groove 41 from the outer wall is 2 mm, and the outer bottom chip-receiving groove 412 is a groove with a depth of 2 mm.

[0036] This structure facilitates the smooth discharge of chips, preventing chip accumulation and scratching of the workpiece surface. During milling, chips are easily generated, and crater wear can occur at the contact point between the chips and the rake face of the insert 31, thus affecting the lifespan of the insert 31. Therefore, this chip groove design for timely chip removal is crucial.

[0037] IV. Blade 31 Structure like Figure 8 , Figure 9 As shown, the blade 31 is a cuboid in shape, with a base material of WC and Co, and a single-layer TiB coating with a thickness of 4 μm. The blade 31 has a length l1 of 16.95 mm and an arc radius R of 0.8 ± 0.1 mm. The protruding length of the cutting edge of the blade 31 is l1-l2, where l2 = 15.06 mm; the width h of the blade 31 is 9.4 ± 0.05 mm, and the cutting edge width h1 is 1.74 mm. The height d1 of the blade 31 is 5.2 ± 0.025 mm, and the protruding length of the cutting edge of the blade 31 is d1-d2, where d2 = 4.15 mm.

[0038] The insert 31 has a chip groove 311 at its center. This chip groove 311 is an open space used to accommodate curled chips from the milling zone, ensuring smooth chip removal. The chip groove 311 of the insert 31 has mounting holes for mounting fasteners 32, and corresponding mounting holes are provided on the mounting surface of the insert 31.

[0039] It can be seen that the insert 31 is fixed to the face milling cutter body 33 by fastening bolts. The insert 31 is a cuboid manufactured by additive manufacturing. The insert 31 has a groove in the center to form a chip groove 41, which is used to accommodate the curled chips in the milling area, so as to facilitate chip removal and prevent chip accumulation from scratching the workpiece surface.

[0040] V. Manufacturing Method In this embodiment, the cutter body 33, coolant flow channel 333, turbulence generation zone 42, and chip groove 41 are all integrally formed using selective laser melting (SLM) additive manufacturing technology. The specific design method includes the following steps: S1: Perform static analysis on the standard tool body 33 to determine the non-optimizable areas of stress concentration on the tool body 33 (such as near the mounting surface of the blade 31) and the optimizable areas (the back of the mounting surface of the blade 31).

[0041] S2: Perform topology optimization on the optimizable region to form a turbulence generation zone 42 and a chip groove 41 outside the cutter body 33.

[0042] S3: The structure of the turbulence generation region 42 is optimized using CFD technology. For example... Figure 10 As shown, by comparing the turbulence effects under different channel outlet shapes through CFD simulation, it was finally determined that the pear-shaped structure with narrow top and bottom and wide middle designed in this application can obtain the best coolant turbulence effect.

[0043] S4: The optimized cutter body 33 is integrally formed using additive manufacturing technology.

[0044] In addition, to further illustrate the beneficial effects and technical advantages of the technical solution of this application, the following comparative examples are set up for comparison with the embodiments of the solution of this application.

[0045] Comparative Example 1 (Standard Tool Body) This comparative example uses a standard face milling cutter body without any topology optimization; its structure is similar to... Figure 1 , Figure 2 The standard face cutter shown is identical. The cutter body is also made of 42CrMo material, with a diameter of 45mm, a diameter of 50mm with inserts, a height of 40.6mm, and a shank mating hole diameter of 22mm. This standard cutter body is a solid structure, without external turbulence generation zones or chip grooves, and also lacks internal coolant channels. External casting cooling is used during milling.

[0046] Based on static analysis and actual testing, the relevant performance parameters of this standard tool body are shown in Table 2: Volume is 43289.588 mm². 3 The maximum equivalent stress is 191.29 MPa, and the deformation is 2.300 × 10⁻⁶ MPa. -3Due to its solid structure and large mass, the tool body exhibits significant inertial force at 10,000 r / min, negatively impacting spindle load and machining stability. Furthermore, the lack of a dedicated chip-collecting structure leads to chip accumulation on the back of the insert mounting surface during high-speed milling, scratching the machined surface. With external casting cooling, the milling fluid struggles to effectively penetrate the high-temperature core area, resulting in low cooling efficiency and rapid insert wear.

[0047] Comparative Example 2 The only difference from Example 1 is that it does not use a chip groove design.

[0048] Comparative Example 3 The only difference from Example 1 is that no turbulence generation zone was designed.

[0049] Comparative Example 4 The only difference from Example 1 is that the turbulence generation zone does not adopt a pear-shaped design that is narrow at the top and bottom and wide in the middle, but instead adopts an hourglass shape that is wide at the top and bottom and narrow in the middle.

[0050] Performance testing Performance tests were conducted on the cutting tools using the above implementation and comparative examples: 1. Performance test results of Example 1: Lightweight design: The optimized blade volume is 22557.376mm. 3 Compared to the standard tool body (43289.588mm) 3 The stress was reduced by 47.89%. After optimization, the stress on the tool body during milling is 247.15 MPa, which is within the allowable stress range of the tool body and meets the design requirements. The stress-deformation comparison is shown in Table 2.

[0051] Table 2 Comparison of stress and deformation before and after optimization

[0052] The first embodiment of this application achieves the following effects: Dynamic balancing performance: The tool body's balance performance was tested using a dynamic balancing machine. The dynamic balancing accuracy and unbalance were measured at rotational speeds of 8000 r / min and 10000 r / min. Test results showed that the tool in Example 1 achieved a dynamic balancing accuracy grade of G5.0 at 8000 r / min and G6.3 at 10000 r / min, meeting the dynamic performance requirements for high-speed tools (G40 balance quality grade specified in ISO 1940 / 1). Theoretical calculations indicate that the dynamic balancing accuracy grade can reach G1.5 at the maximum rotational speed of 10000 r / min.

[0053] Chip removal and cooling effects: Actual milling tests show that the grooved chip groove on the back of the cutter body effectively guides chip removal, preventing chip accumulation and workpiece surface scratches. The specific pear-shaped turbulence generation zone on the front side of the cutter body creates a strong turbulent field after the milling fluid is ejected at high speed, significantly reducing the temperature in the milling area and extending tool life.

[0054] 2. Performance Comparison of Examples and Comparative Examples The key performance indicators of Example 1 were compared with those of the comparative examples above, and the results are as follows:

[0055] As shown in the table above, compared with Comparative Example 1, the solution of this application achieves significant weight reduction while significantly improving chip removal performance and cooling efficiency through the design of the external turbulence generation zone and chip collection groove, and also exhibits superior dynamic balance performance. Compared with Comparative Example 2, the solution of this application avoids the problem of residual powder cleaning caused by complex internal cavities, and achieves better chip removal and turbulent cooling effects through external structural optimization, resulting in superior overall performance while ensuring weight reduction.

[0056] In summary, the key design concepts and advantages of this application are as follows: Advantage 1: Excellent dynamic balance performance When the cutting tool rotates at high speed, due to uneven mass distribution, all parts of the milling cutter will be subjected to large centrifugal forces. When the speed is too high, the centrifugal force will exceed the milling force and become the main load on the cutting tool. This will reduce the bending strength and fracture toughness of the cutting tool, seriously affecting the machining quality, reducing the tool life and the service life of the spindle bearing.

[0057] Therefore, in this application, after structural optimization, a large amount of material was removed from the original tool, and theoretically, the overall structure of the tool has a uniform mass distribution and is centrally symmetrical. However, since the SLM process cannot achieve the precision of the traditional process, and the surface precision of the milling cutter printed by the SLM process cannot reach the level of the traditional process during additive manufacturing, the tool has a large surface roughness and large circumferential and end face runout values. Therefore, it is necessary to conduct theoretical and practical dynamic balancing tests on the tool.

[0058] Calculations show that the designed dynamic balance accuracy level reached G1.5 at a maximum speed of 10000 r / min. A smaller value for the dynamic balance level G indicates a higher balance level for the tool. For general high-speed milling cutters, a balance quality level of G40 as specified in ISO 1940 / 1 is required. Using a dynamic balancing machine to test the tool body's balance performance, the dynamic balance accuracy and unbalance were measured at rotational speeds of 8000 r / min and 10000 r / min. The final tested dynamic balance accuracy levels were G5.0 and G6.3, respectively, meeting the dynamic performance requirements of high-speed tools.

[0059] Advantage 2: Lightweight design of the blade Through static analysis and structural optimization, a lightweight design was implemented for the tool body. The optimized tool body volume was reduced by 47.89%, and the stress during machining was 247.15 MPa, which is within the allowable stress range and meets the design requirements. The total deformation and equivalent stress results were compared with the original tool body: the stress of the standard tool body was 191.29 MPa, and the deformation was 2.300 × 10⁻⁶ MPa. -3 mm, volume is 43289.588 mm. 3 The stress-to-volume ratio is 4.419 × 10⁻⁶. -3 MPa / mm 3 The optimized stress of the tool body is 247.15 MPa, and the deformation is 2.882 × 10⁻⁶. -3 mm, volume is 22557.376 mm² 3 The stress-to-volume ratio is 1.095 × 10⁻⁶. -2 MPa / mm 3 .

[0060] Advantage 3: The cutter body has chip grooves on the outside. During milling, the cutting tool easily generates chips, and the contact point between the chips and the rake face of the insert is prone to crater wear, which affects the life of the insert. At the same time, the blockage and accumulation of chips can easily scratch the surface of the workpiece and reduce the machining quality.

[0061] Therefore, it is particularly important to design chip grooves in specific locations to remove chips in a timely manner. The solution in this application adds chip grooves to the back of the blade mounting surface. The groove design facilitates the effective removal of chips and prevents chips from accumulating during the machining process.

[0062] Advantage 4: The cutter body has a coolant turbulence zone on the outside. Current coolant flow channel design mainly focuses on the flow channel structure inside the tool body. By designing the flow channel structure and adjusting the angle between the nozzle and the chip plane, a larger cooling area can be obtained, thereby improving the cooling effect.

[0063] However, this method provides only a limited improvement in cooling efficiency. Therefore, this application adds a coolant turbulence zone on the front side of the blade mounting surface. For example... Figure 10 As shown, the external turbulence zone was structurally optimized using CFD technology, and the optimal coolant turbulence effect was obtained by adjusting the shape of the channel outlet. The final determined turbulence zone structure was a pear-shaped structure, narrow at the top and bottom and wide in the middle.

[0064] In summary, the embodiments of this application have the following beneficial effects: (1) The overall volume of the blade body is relatively small. The diameter of the blade body L is 45mm, the diameter after the blade is installed is 50mm, the height H is 40.6mm, and the diameter of the mating hole between the handle and the blade body is 22mm.

[0065] (2) The tool body has high tensile strength. The tool body material is 42CrMo, with a tensile strength of 1080MPa and a yield strength of 930MPa, which ensures the structural strength of the tool under high-speed milling.

[0066] (3) External structural topology optimization significantly reduces the weight of the tool body, achieving a 47.89% reduction in tool body volume. The standard tool body volume before optimization was 43289.588 mm. 3 The optimized cutter body volume is 22557.376mm. 3 The stress experienced during machining is 247.15 MPa, which is within the allowable stress of the tool body and meets the design requirements.

[0067] (4) The dynamic balance grade of the cutter body meets the requirements of the dynamic balance accuracy grade of high-speed milling cutters, as tested by a dynamic balancing machine. The dynamic balance accuracy grade is G5.0 at a speed of 8000 r / min; G6.3 at a speed of 10000 r / min; and G1.5 at a maximum speed of 10000 r / min, according to theoretical calculations.

[0068] (5) A chip groove is added to the back of the blade mounting surface. The groove design facilitates the discharge of curled chips during the processing, avoids chip accumulation from scratching the workpiece surface, and improves processing quality.

[0069] (6) A turbulence generation zone is added to the front side of the cutting tool mounting surface, so that the milling coolant can form a turbulent and irregular flow field after being discharged at high speed, which can exchange heat more efficiently and improve cooling efficiency. The external turbulence zone is structurally optimized by CFD technology, and the pear-shaped structure is finally determined to obtain the best coolant turbulence effect.

[0070] (7) Compared with the initial tool body, the tool body of the present application saves 47.89% of the material, reduces the inertial force of the tool during the milling process, and is conducive to improving the machining stability and spindle life.

[0071] It should be noted that: In this embodiment, the number of blade mounting surfaces evenly distributed along the circumference of the blade body can be four. Based on the above design concept, it can also be designed as six or eight, with the corresponding number of blades remaining the same. The specific parameters of the blades can be adjusted according to processing requirements, but the base material and coating material remain unchanged. Other structures and manufacturing methods are the same as in embodiment 1 and will not be repeated here.

[0072] Furthermore, those skilled in the art should understand that although many problems exist in the prior art, each embodiment or technical solution of this application can be improved in only one or a few aspects, without necessarily solving all the technical problems listed in the prior art or background art simultaneously. Those skilled in the art should understand that any content not mentioned in a claim should not be construed as a limitation on that claim.

[0073] Although this document frequently uses terms such as blade, fastener, blade body, base, mounting base, blade mounting notch, coolant flow channel, chip groove, turbulence generation zone, and chip groove, the possibility of using other terms is not excluded. These terms are used merely for the convenience of describing and explaining the essence of this application; interpreting them as any additional limitation would contradict the spirit of this application. The terms "first," "second," etc. (if present) in the description, claims, and accompanying drawings of the embodiments of this application are used to distinguish similar objects and are not necessarily used to describe a specific order or sequence.

[0074] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of this application, and are not intended to limit them. Although this application has been described in detail with reference to the above embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the above embodiments, or equivalent substitutions can be made to some or all of the technical features. Such modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of this application.

Claims

1. A lightweight additive manufacturing tool based on external structure topology optimization, comprising a tool body (33), an insert (31), and a fastener (32), characterized in that: The blade body (33) has a blade mounting surface along its circumference, and a blade mounting notch (3321) is provided on the blade mounting surface. The blade (31) is mounted at the blade mounting notch (3321) by fasteners (32). The blade body (33) has a lightweight main body configuration, and the blade body (33) is provided with a turbulence generation zone (42) and a chip groove (41) on the outside. The turbulence generation zone (42) is located on the front side of the blade mounting surface and is an arc-shaped structure that is recessed into the blade body (33); the chip groove (41) is located on the back side of the blade mounting surface and is a groove structure that is recessed into the blade body (33), and the turbulence generation zone (42) is connected to the coolant flow channel (333) inside the blade body (33).

2. The lightweight additive manufacturing tool based on external structure topology optimization according to claim 1, characterized in that: The chip groove (41) is a groove structure, and the boundary of the groove structure is transitioned by an arc surface.

3. The lightweight additive manufacturing tool based on external structure topology optimization according to claim 1, characterized in that: Along the axial direction of the blade body (33), the blade body (33) includes a base (331) and a mounting base (332) in sequence. The mounting base (332) is provided with the blade mounting surface; Along the axial direction of the blade body (33), the turbulence generation zone (42) extends from the top of the base (331) to the top of the mounting base (332); wherein, from the top of the base (331) to the bottom of the blade mounting surface, the angle between the tangent of the turbulence generation zone (42) and the horizontal is α1, and the rate of change of α1 gradually decreases; from the bottom of the blade mounting surface to the top of the blade body (33), the angle between the tangent of the turbulence generation zone (42) and the horizontal is α2, and the rate of change of α2 gradually increases, so that the turbulence generation zone (42) forms a streamlined arc surface structure with a central concave shape.

4. The lightweight additive manufacturing tool based on external structure topology optimization according to claim 1, characterized in that: The turbulence generation zone (42) is pear-shaped, narrow at the top and bottom and wide in the middle.

5. The lightweight additive manufacturing tool based on external structure topology optimization according to claim 4, characterized in that: Along the axial direction of the cutter body (33), the coolant channel (333) extends from the lower part of the mounting base (332) to the top of the cutter body (33), and the upper part of the turbulence generation zone (42) is connected to the coolant channel (333) through a liquid hole; And / or, the width ratio of the top, middle and bottom sides of the pear-shaped structure is 0.4:0.85:0.

4.

6. The lightweight additive manufacturing tool based on external structure topology optimization according to claim 5, characterized in that: The blade body (33) is provided with a mounting through hole in the middle, and the mounting through hole is provided along the axial direction of the blade body (33); The coolant channel (333) does not penetrate the top of the blade body (33). The coolant channel (333) extends to the mounting through hole and the outer wall of the blade body (33) on both sides in the width direction, respectively. The coolant channel (333) does not penetrate the mounting through hole and the outer wall of the blade body (33), so that the coolant channel (333) forms a blind groove structure.

7. The lightweight additive manufacturing tool based on external structure topology optimization according to claim 1, characterized in that: The blade (31) is in the shape of a cuboid, and the center of the blade (31) has a blade chip groove (311). The blade (31) has a chip groove (311) with a mounting hole for mounting the fastener (32), and the blade mounting surface has a mounting hole for mounting the fastener (32).

8. The lightweight additive manufacturing tool based on external structure topology optimization according to claim 1, characterized in that: The blade body (33) has blade mounting surfaces distributed at equal angles along its circumference; And / or, a cylindrical mounting through hole is provided in the middle of the blade body (33), and the mounting through hole is arranged along the axial direction of the blade body (33).

9. The lightweight additive manufacturing tool based on external structure topology optimization according to claim 1, characterized in that: The base material of the blade (31) is WC and Co, and the surface of the blade (31) has a coating, which is a single layer of TiB.

10. A design method for lightweight additive manufacturing tools based on external structure topology optimization as described in any one of claims 1-9, characterized in that, Includes the following steps: S1: Perform static analysis on the standard tool body to determine the non-optimizable and optimizable stress concentration areas on the tool body; S2: Perform topology optimization on the optimizable region to form a turbulence generation zone (42) and a chip groove (41) outside the cutter body. S3: The structure of the turbulence generation zone (42) is optimized using CFD technology; S4: The optimized cutter body (33) is integrally formed by additive manufacturing technology.

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