Milling tool and subtractive machining method suitable for powder laying additive and subtractive hybrid manufacturing

Abstract

The application is suitable for a milling cutter for powder laying type additive and subtractive composite manufacturing and a subtractive machining method, relates to a powder laying type additive and subtractive composite manufacturing tool technical field, and particularly relates to a milling cutter for powder laying type additive and subtractive composite manufacturing and a subtractive machining method.The application comprises a tool head, a tool neck and a tool handle; the tool head is a T-shaped tool head and is composed of a cutting part and a connecting part; the cutting part is composed of four tool teeth; a plurality of microgrooves with the same size are machined on the tool face of each tool tooth; and the plurality of microgrooves divide each tool tooth into a plurality of microedges with the same size.The technical scheme of the application solves the problems in the prior art that the microedge cutter cannot guarantee the requirement of chip powderization, the size structure of the cutter is limited, it is difficult to meet the three-axis type finishing of complex parts, such as internal runner, hole, overhanging surface and other types of fine feature structures, the space staggered microedges cannot guarantee the machining precision, and the subtractive machining efficiency is low.

Description

Technical Field

[0001] This invention relates to milling cutters and subtractive machining methods for powder-based additive and subtractive composite manufacturing, and particularly to a milling cutter and subtractive machining method suitable for powder-based additive and subtractive composite manufacturing. Background Technology

[0002] Powder-layout additive-subtractive composite manufacturing combines the advantages of laser powder bed fusion additive manufacturing and precision milling, enabling the rapid fabrication of high-precision, high-quality complex parts made of different materials. This shortens manufacturing cycles, reduces production costs, and has broad application prospects. However, during the subtractive machining process, chips inevitably fall onto the interface between the additive and subtractive materials and mix with the additive powder during subsequent powder-laying. Since each powder layer is only 40-70 μm thick, with an average powder size of approximately 40 μm, these uncontrolled large chips severely affect the powder-laying quality in subsequent processes, leading to uneven interfacial structure and impacting component performance. Therefore, developing a novel cutting tool and subtractive manufacturing method to pulverize the chips is crucial for ensuring subsequent powder-laying quality and improving the performance of powder-layout additive-subtractive composite manufactured components.

[0003] Currently, in the field of machining, controlling chip morphology is mostly achieved by changing cutting elements. However, this requires comprehensive consideration of factors such as material hardness, strength, and tool performance, and obtaining optimal parameters through multiple experiments, which consumes a lot of time and effort. Therefore, many scholars have proposed methods for controlling chip morphology based on micro-edge tools. Patent (publication number: CN201609771U) proposes a novel micro-edge structure for machining titanium alloys. It selects optimized rake and clearance angles based on roughing and finishing requirements, thereby reducing cutting forces on titanium alloys and controlling the morphology and motion characteristics of titanium alloy chips. However, the chip size produced by this tool is still too large, failing to meet the requirements for powdering. Patent (publication number: CN212310955U) describes an intermittent micro-edge micro-milling tool that uses a helical double-edge structure and machines spatially interlaced micro-edges on the side edges of the two cutting teeth. The reduced blunt radius of the micro-edge reduces the plowing effect, making it easier to form chips and effectively improving the stability of the micro-cutting process. However, this tool has a certain feed motion during milling, and the spatially interlaced micro-edges cannot effectively guarantee the machining accuracy required for additive and subtractive manufacturing, making it difficult to control the size of chips and powder to be on the same order of magnitude. In addition, due to the limitations of its own size and structure, the above tools are difficult to meet the requirements of three-axis finishing of fine features such as internal channels, holes, and overhanging surfaces of complex parts.

[0004] In view of the problems existing in the prior art, it is necessary to research and design a new milling tool and subtractive machining method suitable for powder-spreading additive and subtractive composite manufacturing, so as to overcome the problems existing in the prior art. Summary of the Invention

[0005] The existing micro-edge cutting tools cannot guarantee chip pulverization, and their size and structure are limited, making it difficult to meet the three-axis finishing requirements of complex parts with fine features such as internal channels, holes, and overhanging surfaces. Furthermore, the spatially interlaced micro-edges cannot guarantee machining accuracy, resulting in low subtractive machining efficiency. Therefore, this invention provides a milling tool and subtractive machining method suitable for powder-layout composite manufacturing. The milling tool in this invention controls chip morphology based on micro-edges, increases tooth thickness to create a multi-row parallel micro-edge structure, and combines this with the proposed subtractive machining method to precisely control chip size, pulverizing the chips to reduce their impact on powder-layout quality and the uniformity of the additive-subtractive interface. The inclination angle of the feature parts of the workpiece is measured beforehand, and different inclination angles of the cutting head are selected based on these angles to achieve forming machining, ensuring machining accuracy and improving machining efficiency.

[0006] The technical means employed in this invention are as follows:

[0007] A milling cutter suitable for powder-spreading additive-subtractive composite manufacturing includes: a cutter head, a cutter neck, and a cutter shank;

[0008] Furthermore, the cutter head is a T-shaped cutter head, consisting of a cutting section and a connecting section;

[0009] Furthermore, the cutting part consists of four cutting teeth; several micro-grooves of the same size are machined on the back face of each cutting tooth; the several micro-grooves divide each cutting tooth into several micro-cutting edges of the same size.

[0010] Furthermore, the blade teeth have a spiral structure;

[0011] Furthermore, the ratio of the micro-edge width w1 to the micro-groove width w2 on the back face of the cutting tooth is 3:2.

[0012] Furthermore, the cutting head includes: vertical cutting head, suspended cutting head, and inclined cutting head;

[0013] Furthermore, the longitudinal section of the cutting part of the vertical cutter head is a rectangular surface with vertical sides, and the edge of the product it produces is a vertical surface.

[0014] Furthermore, the longitudinal section of the cutting part of the suspended cutter head is a sloping surface with both sides inclined outward from top to bottom, and the edge of the product it produces is a suspended surface.

[0015] Furthermore, the longitudinal section of the cutting part of the ramp cutter head is a hanging surface with both sides inclined inward from top to bottom, and the edge of the machined product is a ramp surface.

[0016] Furthermore, the rake angle γ0 of the micro-blade is between -5° and 10°, and the clearance angle α0 is between 5° and 10°;

[0017] Furthermore, the micro-cutting edge can be further subdivided into end-cutting edge and side-cutting edge. The end-cutting edge is located at the bottom of the micro-cutting edge to improve its cutting performance, while the side-cutting edge is located at the junction of the rake face and the flank face of the micro-cutting edge and is used for finishing features such as vertical surfaces, overhanging surfaces and inclined surfaces.

[0018] Furthermore, a chip removal groove is provided between the beginning and end of two adjacent cutting teeth.

[0019] Furthermore, the cutting part, connecting part, cutter neck, and cutter shank are integrally formed and machined;

[0020] Furthermore, the thickness of the cutting portion is L0;

[0021] Furthermore, the length of the connecting part is L1;

[0022] Furthermore, the length of the blade neck is L2;

[0023] Furthermore, the length of the tool holder is L3;

[0024] Furthermore, L2 = 2L1;

[0025] Furthermore, L3 = 4L2.

[0026] Furthermore, the angle ψ between the beveled surface of the blade neck and the axial direction is between 5° and 75°;

[0027] Furthermore, the bottom edge of the tool holder has a 45° chamfer.

[0028] Furthermore, the subtractive machining method is applicable to three-axis milling. The subtractive machining stage is located between two consecutive additive machining stages, and the subtractive machining is carried out from top to bottom. During the machining process, the cutting depth in the horizontal direction is controlled to be 50μm each time, and the cycle is repeated several times until the surface accuracy meets the requirements. This is one subtractive machining operation.

[0029] Furthermore, in three-axis milling, the cutting part first moves axially to the horizontal plane of the workpiece, and then moves radially toward the machined surface of the workpiece to perform subtraction machining. After machining, the cutter retracts in the opposite direction to the workpiece to complete the first milling operation. After the first operation, the milling cutter moves downward by a distance of (w1+w2) / 2 so that the unmachined surface during the first operation is completely enveloped by the micro-edge and placed in the center. Then, it moves radially toward the workpiece again to perform subtraction machining. After machining, the cutter retracts in the opposite direction to the workpiece to complete the second milling operation.

[0030] Furthermore, after completing the second milling operation, the milling cutter moves downwards by L0 and repeats the above operation. Before milling, the maximum axial machining depth needs to be determined based on the characteristics of the workpiece to avoid interference between the tool and the workpiece during the machining process.

[0031] Compared with the prior art, the present invention has the following advantages:

[0032] 1. The present invention provides a milling tool suitable for powder-laying additive and subtractive composite manufacturing. This tool is based on a micro-edge design to control the chip morphology. The T-shaped cutter head consists of a cutting part and a connecting part. Several micro-edges are machined on the back face of the cutting teeth of the cutting part to refine the chips. The machining efficiency is improved by controlling the thickness of the cutting teeth. The connecting part is connected to the cutter neck with an inclination angle to avoid interference with the machined part. This structure has the advantage of three-axis precision machining of fine features such as internal flow channels, holes, and overhanging surfaces of complex parts. Different inclination angles of the cutter head are selected according to the inclination angle of the feature parts of the machined part to achieve forming machining, reduce costs, and improve machining efficiency while ensuring machining accuracy.

[0033] 2. The present invention provides a subtractive machining method for milling cutters suitable for powder-spreading additive-subtractive composite manufacturing. This method is applicable to three-axis milling subtractive machining. During the subtractive machining process, the rough additive surface is finished by controlling the cutting depth in the horizontal direction and the axial movement distance. The micro-edge structure of the milling cutter's cutting part is combined to achieve the technical requirement of chip powdering.

[0034] In summary, the technical solution of this invention solves the problems in the prior art where micro-blade tools cannot meet the requirements of chip pulverization, the tool's own size and structure are limited, making it difficult to achieve three-axis finishing of complex parts with fine features such as internal channels, holes and overhanging surfaces, and the spatially intersecting micro-blades cannot guarantee machining accuracy and have low material reduction efficiency. Attached Figure Description

[0035] To more clearly illustrate the technical solutions in the embodiments of the present invention 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 the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0036] Figure 1 This is a schematic diagram of the milling tool structure of the present invention;

[0037] Figure 2 This is a schematic diagram of the cutter head structure of the present invention;

[0038] Figure 3 For the present invention Figure 2 Enlarged schematic diagram of the middle section (I);

[0039] Figure 4 This is a side view of the blade head of the present invention;

[0040] Figure 5 For the present invention Figure 4 Enlarged schematic diagram of the middle S section;

[0041] Figure 6 This is an enlarged schematic diagram of the blade neck of the present invention;

[0042] Figure 7 This is a schematic diagram of the subtractive processing method of the present invention;

[0043] Figure 8 For the present invention Figure 7 Enlarged diagram of section A in the middle;

[0044] Figure 9 For the present invention Figure 7 Enlarged schematic diagram of section B in the middle;

[0045] Figure 10 This is a schematic diagram of the vertical cutter head structure of the present invention;

[0046] Figure 11 This is a schematic diagram of the suspended cutter head structure of the present invention;

[0047] Figure 12 This is a schematic diagram of the inclined cutter head structure of the present invention.

[0048] In the diagram: 1. Cutting section; 2. Connecting section; 3. Neck; 4. Tool holder; 5. Cutting teeth; 6. Micro-edge; 7. Micro-groove; 8. End edge; 9. Side edge; 10. Chip groove; 11. Workpiece; 12. Machined surface; 13. Unmachined surface; 14. Vertical cutter head; 15. Overhanging cutter head; 16. Inclined cutter head. a. Schematic diagram of the first milling operation; b. Result after the first milling operation; c. Schematic diagram of the second milling operation; d. Result after the second milling operation. Detailed Implementation

[0049] It should be noted that, unless otherwise specified, the embodiments and features described in the present invention can be combined with each other. The present invention will now be described in detail with reference to the accompanying drawings and embodiments.

[0050] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. The following description of at least one exemplary embodiment is merely illustrative and is in no way intended to limit the present invention or its application or use. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0051] It should be noted that the terminology used herein is for the purpose of describing particular embodiments only and is not intended to limit the scope of exemplary embodiments according to the invention. As used herein, the singular form is intended to include the plural form as well, unless the context clearly indicates otherwise. Furthermore, it should be understood that when the terms "comprising" and / or "including" are used in this specification, they indicate the presence of features, steps, operations, devices, components, and / or combinations thereof.

[0052] Unless otherwise specifically stated, the relative arrangement, numerical expressions, and values ​​of the components and steps set forth in these embodiments do not limit the scope of the invention. It should also be understood that, for ease of description, the dimensions of the various parts shown in the drawings are not drawn to actual scale. Techniques, methods, and devices known to those skilled in the art may not be discussed in detail, but where appropriate, such techniques, methods, and devices should be considered part of the specification. In all examples shown and discussed herein, any specific values ​​should be interpreted as merely exemplary and not as limitations. Therefore, other examples of exemplary embodiments may have different values. It should be noted that similar reference numerals and letters in the following figures denote similar items; therefore, once an item is defined in one figure, it need not be further discussed in subsequent figures.

[0053] In the description of this invention, it should be understood that the orientation or positional relationship indicated by directional terms such as "front, back, up, down, left, right", "horizontal, vertical, horizontal" and "top, bottom" is generally based on the orientation or positional relationship shown in the accompanying drawings, and is only for the convenience of describing this invention and simplifying the description. Unless otherwise stated, these directional terms do not indicate or imply that the device or element referred to must have a specific orientation or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation on the scope of protection of this invention. The directional terms "inner" and "outer" refer to the inner and outer contours relative to the outline of each component itself.

[0054] For ease of description, spatial relative terms such as "above," "on top of," "on the upper surface of," "above," etc., are used herein to describe the spatial positional relationship of a device or feature as shown in the figures to other devices or features. It should be understood that spatial relative terms are intended to encompass different orientations in use or operation beyond the orientation of the device as described in the figures. For example, if the device in the figures were inverted, a device described as "above" or "on top of" other devices or structures would subsequently be positioned as "below" or "under" other devices or structures. Thus, the exemplary term "above" can include both "above" and "below." The device may also be positioned in other different ways (rotated 90 degrees or in other orientations), and the spatial relative descriptions used herein will be interpreted accordingly.

[0055] Furthermore, it should be noted that the use of terms such as "first" and "second" to define components is merely for the purpose of distinguishing the corresponding components. Unless otherwise stated, the above terms have no special meaning and therefore should not be construed as limiting the scope of protection of this invention.

[0056] like Figure 1 As shown, the present invention provides a milling tool suitable for powder-laying additive-subtractive composite manufacturing, comprising: a cutting head, a cutting neck 3, and a cutting shank 4;

[0057] like Figure 1 , 2 As shown, the cutter head is a T-shaped cutter head, consisting of a cutting part 1 and a connecting part 2; the cutting part 1 consists of four cutting teeth 5; several micro-grooves 7 of the same size are machined on the back face of each cutting tooth 5; the several micro-grooves 7 divide each cutting tooth 5 into several micro-blades 6 of the same size.

[0058] The cutting part 1, connecting part 2, cutting neck 3 and cutting shank 4 are integrally formed; the bottom edge of the cutting shank 4 is chamfered at 45°; the thickness of the cutting part 1 is L0; the length of the connecting part 2 is L1; the length of the cutting neck 3 is L2; ​​the length of the cutting shank 4 is L3; L2 = 2L1; L3 = 4L2.

[0059] like Figure 2 As shown, the cutting tooth 5 has a spiral structure; the ratio of the width w1 of the micro-edge 6 to the width w2 of the micro-groove 7 on the back face of the cutting tooth 5 is 3:2.

[0060] like Figure 10-12 As shown, the cutting head includes: a vertical cutting head 14, a suspended cutting head 15, and a ramp cutting head 16; the longitudinal section of the cutting part 1 of the vertical cutting head 14 is a rectangular surface with both sides being vertical, and the edge of the product it produces is a vertical surface; the longitudinal section of the cutting part 1 of the suspended cutting head 15 is a ramp surface with both sides being inclined outward from top to bottom, and the edge of the product it produces is a suspended surface; the longitudinal section of the cutting part 1 of the ramp cutting head 16 is a suspended surface with both sides being inclined inward from top to bottom, and the edge of the product it produces is a ramp surface.

[0061] like Figure 5 As shown, the rake angle γ0 of the micro-blade 6 is between -5° and 10°, and the clearance angle α0 is between 5° and 10°.

[0062] like Figure 3 As shown, the micro-blade 6 can be further subdivided into end blade 8 and side blade 9. The end blade 8 is located at the bottom of the micro-blade 6 to improve its cutting performance. The side blade 9 is located at the junction of the rake face and the flank face of the micro-blade and is used for finishing features such as vertical surfaces, overhanging surfaces and inclined surfaces.

[0063] like Figure 4 As shown, a chip removal groove 10 is provided between the head and tail of two adjacent cutting teeth 5.

[0064] like Figure 6 As shown, the angle ψ between the inclined surface of the blade neck 3 and the axial direction is between 5° and 75°.

[0065] like Figure 7-9 As shown, the subtractive machining method is applicable to three-axis milling. The subtractive stage is located between two consecutive additive stages, and the subtractive machining is carried out from top to bottom. During the machining process, the cutting depth in the horizontal direction is controlled to be 50μm each time, and the cycle is repeated several times until the surface accuracy meets the requirements. This is one subtractive machining operation.

[0066] like Figure 7-9 As shown, in a three-axis milling process, the cutting part 1 first moves axially to the horizontal plane of the workpiece 11, and then moves radially towards the machining surface 12 of the workpiece 11 to perform subtraction machining. Figure 7 As shown in (a); after machining, the tool is retracted in the opposite direction to the workpiece 11 to complete the first milling operation, and the machining effect is as shown in (a). Figure 7As shown in (b); after the first machining is completed, the milling cutter cutting part 1 moves downward by a distance of (w1+w2) / 2, so that the unmachined surface 13 during the first machining is completely enveloped by the micro-edge 6 and is in the center; then it moves radially towards the workpiece 11 again for subtraction machining, as shown in (b). Figure 7 As shown in (c); after machining, retract the tool in the opposite direction to the machined part 11 to complete the second milling process. The machining effect is as shown in (c). Figure 7 As shown in (d).

[0067] like Figure 7-9 As shown, after completing the second milling operation, the milling cutter moves downward L0 and repeats the above operation. Before milling, the maximum axial machining depth needs to be determined according to the characteristics of the workpiece 11 to avoid interference between the tool and the workpiece 11 during the machining process.

[0068] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, and not to limit them; although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some or all of the technical features; and these 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 the present invention.

Claims

1. A subtractive machining method for milling cutters suitable for powder-spreading additive-subtractive composite manufacturing, comprising: The blade head, blade neck (3), and blade shank (4) are characterized by: The cutting head is a T-shaped cutting head, which consists of a cutting part (1) and a connecting part (2); The cutting part (1) consists of four cutting teeth (5); several micro-grooves (7) of the same size are machined on the back face of each cutting tooth (5); the several micro-grooves (7) divide each cutting tooth (5) into several micro-blades (6) of the same size. The micro-blade (6) chips and powders are on the same order of magnitude in size; The cutting head is configured to be selected according to the inclination angle of the feature part (11) being processed, including: a vertical cutting head (14) for processing vertical surfaces, a suspended cutting head (15) for processing overhanging surfaces, and a sloping cutting head (16) for processing inclined surfaces. In a three-axis milling process, the cutting part (1) first moves axially to the horizontal plane of the workpiece (11), and then moves radially toward the machining surface (12) of the workpiece (11) to perform subtraction machining. After the machining is completed, the cutting part (1) retracts in the opposite direction to the workpiece (11) to complete the first milling process. After the first machining is completed, the milling cutter cutting part (1) moves downward by a distance of (w1+w2) / 2 so that the unmachined surface (13) during the first machining is completely enveloped by the micro-edge (6) and is in the center. Then, it moves radially toward the workpiece (11) again to perform subtraction machining. After the machining is completed, the cutting part retracts in the opposite direction to the workpiece (11) to complete the second milling process.

2. The subtractive machining method for milling cutters suitable for powder-laying additive-subtractive composite manufacturing according to claim 1, characterized in that: The blade teeth (5) have a spiral structure; The ratio of the width w1 of the micro-edge (6) on the back face of the cutting tooth (5) to the width w2 of the micro-groove (7) is 3:

2.

3. The subtractive machining method for milling tools suitable for powder-laying additive-subtractive composite manufacturing according to claim 1, characterized in that: The longitudinal section of the cutting part (1) of the vertical cutter head (14) is a rectangular surface with vertical sides, and the edge of the product it produces is a vertical surface. The longitudinal section of the cutting part (1) of the suspended cutter head (15) is a sloping surface with both sides inclined from top to bottom outward, and the edge of the processed product is a suspended surface. The longitudinal section of the cutting part (1) of the slope cutter head (16) is a hanging surface with both sides inclined from top to bottom inward, and the edge of the processed product is a slope surface.

4. The subtractive machining method for milling cutters suitable for powder-laying additive-subtractive composite manufacturing according to claim 1 or 2, characterized in that: The front angle γ0 of the micro-blade (6) is between -5° and 10°, and the rear angle α0 is between 5° and 10°; The micro-blade (6) is further subdivided into end blade (8) and side blade (9). The end blade (8) is located at the bottom of the micro-blade (6) to improve its cutting performance. The side blade (9) is located at the junction of the rake face and the flank face of the micro-blade (6) and is used for finishing vertical, overhanging and inclined surface features.

5. The subtractive machining method for milling cutters suitable for powder-laying additive-subtractive composite manufacturing according to claim 1, characterized in that: Chip removal grooves (10) are provided between the head and tail of two adjacent cutting teeth (5).

6. The subtractive machining method for milling cutters suitable for powder-laying additive-subtractive composite manufacturing according to claim 1, characterized in that: The cutting part (1), connecting part (2), blade neck (3) and blade holder (4) are integrally formed; The thickness of the cutting part (1) is L0; The length of the connecting part (2) is L1; The length of the blade neck (3) is L2; The length of the tool holder (4) is L3; The L2 = 2L1; The L3 is 4L2.

7. The subtractive machining method for milling cutters suitable for powder-laying additive-subtractive composite manufacturing according to claim 1 or 6, characterized in that: The angle ψ between the inclined surface of the blade neck (3) and the axial direction is between 5° and 75°; The bottom edge of the tool holder (4) is chamfered at 45°.

8. The subtractive machining method for milling cutters suitable for powder-laying additive-subtractive composite manufacturing according to claim 1, characterized in that: The aforementioned subtractive machining method is applicable to three-axis milling in powder-based additive-subtractive composite manufacturing. The subtractive machining process is located between two consecutive additive machining processes and is carried out from top to bottom. During the machining process, the horizontal cutting depth is controlled to be 50 μm each time, and the process is repeated several times until the surface accuracy meets the requirements, which is one subtractive machining operation.

9. The subtractive machining method for milling cutters suitable for powder-laying additive-subtractive composite manufacturing according to claim 1, characterized in that: After the second milling operation is completed, the milling cutter moves downward L0 and the operation is repeated. Before the milling operation, the maximum axial machining depth needs to be determined according to the characteristics of the workpiece (11) to avoid interference between the tool and the workpiece (11) during the machining process.

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