Micro-diameter rotary cutting tool adopting composite groove profile

Abstract

The utility model discloses a micro-diameter rotary cutting tool adopting a composite groove profile, which is characterized in that the composite groove profile of a chip groove is jointly determined by the shape of a front tool face and the shape of a groove bottom face, the front tool face is provided with a corrugated front tool face concave-convex part, and the groove bottom face is provided with a corrugated front tool face concave-convex part. One or a plurality of groove bottom surface bulges which are arranged at intervals are arranged on the groove bottom surface, so that the cross sectional area of the cutter body is locally increased in the area where the groove bottom surface bulges are arranged. Aiming at the three technical bottlenecks of difficult chip removal, insufficient rigidity and vibration sensitivity of the micro-diameter milling cutter in precision machining, the performance of the micro-diameter milling cutter is comprehensively improved through the innovative groove profile design.

Description

Technical Field

[0001] This utility model relates to the field of cutting technology, specifically, to a micro-diameter rotary cutting tool using a composite groove type. Background Technology

[0002] In the field of precision manufacturing, micro-end mills, as core tools for achieving sub-millimeter-level feature machining, directly determine the machining accuracy and production efficiency of micro-components. Micro-end mills are widely used in high-end manufacturing fields such as microelectronic packaging structures, precision medical implants (e.g., micro-threaded bone screws), aerospace micro-sensor cavities, and optical diffraction elements. There is an inherent contradiction between tool miniaturization and structural strength. Traditional design methods, when reducing tool size, result in a geometric decrease in bending and torsional rigidity, making them highly susceptible to elastic deformation and even fracture during machining. Furthermore, the heat dissipation and chip removal performance of existing micro-end mills are insufficient to meet the demands of high-precision machining. Due to limited chip groove space, chips tend to remain in the cutting area when machining viscous materials, leading to secondary cutting and accelerated tool wear. In addition, insufficient heat dissipation channels in the cutting edge area cause heat accumulation during cutting. These technical defects result in generally low lifespans for micro-end mills when machining high-temperature alloys and ceramics, and insufficient surface quality stability, severely restricting their application in precision manufacturing and hindering the further development of precision machining technology. Utility Model Content

[0003] This utility model provides a groove shape for a micro-diameter rotary cutting tool and the micro-diameter rotary cutting tool itself, specifically including the following embodiments:

[0004] Implementation Method 1. A micro-diameter rotary cutting tool employing a composite groove type, characterized in that,

[0005] The micro-diameter rotary cutting tool includes:

[0006] The blade body has a diameter of 0.2 mm to 6 mm.

[0007] Optional tool holders for direct or indirect connection to machine tools.

[0008] An optional chin for connecting the blade body and the handle.

[0009] The tool body has multiple cutting edges arranged along its circumference, and chip removal grooves extending along the axial direction of the tool body are provided between adjacent cutting edges.

[0010] The chip removal groove has a face facing the cutting rotation direction, which is the rake face.

[0011] The chip removal groove also has a concave arc surface that connects to the rake face and extends along the axial direction of the tool body, which is the bottom surface of the groove.

[0012] The composite groove shape of the chip removal groove is determined by the shapes of the rake face and the bottom surface of the groove.

[0013] in,

[0014] The rake face has a corrugated rake face protrusion and concavity, which includes one or more rake face protrusions and one or more rake face concave portions. The rake face protrusions and the rake face concave portions are arranged sequentially in the extending direction of the chip removal groove, so that the rake face intersects with the outer peripheral surface of the tool body to form the corrugated cutting edge of the cutting edge.

[0015] The bottom surface of the groove is provided with one or more groove bottom surface protrusions arranged at intervals, thereby increasing the cross-sectional area of ​​the cutter body locally in the area where the groove bottom surface protrusions are provided, and the groove bottom surface protrusions are provided so that the cross-sectional area of ​​the chip removal groove at that location is reduced by less than 30%.

[0016] Embodiment 2. The micro-diameter rotary cutting tool according to Embodiment 1 is characterized in that the height of the protrusion on the bottom surface of the groove accounts for 20% to 80% of the depth of the chip removal groove, for example 20% to 60%, for example 40% to 60%.

[0017] Implementation Method 3. The micro-diameter rotary cutting tool according to Implementation Method 1 is characterized in that, in the axial direction of the tool body, the groove bottom surface protrusion has a convex arc-shaped top profile, and the axial width of the groove bottom surface protrusion gradually increases from the top to the root, and the ratio of its top width to its root width is 0.3 to 0.8:1, for example, 0.4 to 0.7:1.

[0018] Embodiment 4. The micro-diameter rotary cutting tool according to Embodiment 1 is characterized in that, when multiple groove bottom surface protrusions are provided, the ratio of the distance between adjacent groove bottom surface protrusions to the depth of the chip removal groove is 0.3 to 10, for example 0.5 to 10, for example 0.6 to 10.

[0019] Implementation Method 5. The micro-diameter rotary cutting tool according to Implementation Method 1 is characterized in that the groove bottom surface protrusion is simultaneously provided at the corresponding positions of adjacent chip removal grooves, that is, the groove bottom surface protrusion is distributed along the circumferential direction of the tool body in the chip removal groove, thereby increasing the core thickness of the tool body.

[0020] Implementation Method 6. The micro-diameter rotary cutting tool according to Implementation Method 5 is characterized in that the groove bottom protrusions provided at different positions along the axial direction of the tool body have varying dimensions, so that the core thickness increase value at different positions along the axial direction of the tool body varies.

[0021] Implementation Method 7. The micro-diameter rotary cutting tool according to Implementation Method 1, characterized in that the groove bottom surface protrusion is only provided within the range of increased core thickness of the tool body.

[0022] Implementation Method 8. The micro-diameter rotary cutting tool according to Implementation Method 1 is characterized in that the same groove bottom surface protrusion has a varying height, and its highest point is located at the lowest point of the concave arc surface.

[0023] Implementation Method 9. The micro-diameter rotary cutting tool according to Implementation Method 1 is characterized in that, in the direction perpendicular to the axis of the tool body, the height of the protrusion on the bottom surface of the same groove changes in opposite directions to the depth of the bottom surface of the groove.

[0024] Embodiment 10. The micro-diameter rotary cutting tool according to Embodiment 1 is characterized in that, in a direction perpendicular to the axis of the tool body, the bottom surface of the same groove protrudes with a convex arc-shaped top profile.

[0025] Embodiment 11. The micro-diameter rotary cutting tool according to Embodiment 1, characterized in that the top of the groove bottom protrusion is connected to the rake face, that is, the groove bottom protrusion extends to the rake face.

[0026] Embodiment 12. The micro-diameter rotary cutting tool according to Embodiment 1 is characterized in that the top of the protrusion of the groove bottom surface is connected to the recess of the rake face, that is, the protrusion of the groove bottom surface extends into the recess of the rake face.

[0027] Embodiment 13. The micro-diameter rotary cutting tool according to Embodiment 1, characterized in that the bottom protrusion of the groove extends downward or horizontally in the direction of the cutting edge within the chip removal groove.

[0028] Implementation Method 14. The micro-diameter rotary cutting tool according to Implementation Method 1 is characterized in that, in the axial direction of the tool body, the axial dimension of the protrusion on the bottom surface of the chip removal groove is less than or equal to one-half of the axial dimension of the bottom surface, for example, less than or equal to one-third of the axial dimension of the bottom surface.

[0029] Embodiment 15. The micro-diameter rotary cutting tool according to Embodiment 1, characterized in that the wavelength of the corrugated cutting edge is 0.2 mm to 1.5 mm and the amplitude is 5 micrometers to 0.5 mm.

[0030] Embodiment 16. A method for preparing a micro-diameter rotary cutting tool according to any one of Embodiments 1 to 15, characterized in that the groove shape is prepared by a machining method that does not produce thermal damage.

[0031] Implementation Method 17. The method according to Implementation Method 16, wherein the groove shape is prepared by femtosecond pulsed laser processing method.

[0032] Embodiment 18. A method for preparing a micro-diameter rotary cutting tool according to any one of Embodiments 1 to 15, characterized in that it comprises the following steps:

[0033] Chip removal grooves are ground into the rotary cutting tool blank to form the rake face and the bottom surface of the groove.

[0034] The composite groove is formed by machining a corrugated rake face with concave and convex parts on the rake face and a groove bottom protrusion on the groove bottom surface using a femtosecond pulsed laser processing method.

[0035] This application addresses three major technical bottlenecks faced by micro-diameter end mills (diameter ≤ 6mm) in precision machining: chip removal difficulties, insufficient rigidity, and vibration sensitivity. Through an innovative groove design, it achieves a comprehensive improvement in the performance of micro-diameter tools. Its beneficial technical effects mainly include:

[0036] 1. The unique composite groove formed by the corrugated rake face and the raised bottom surface of the groove in this application enables the chips to leave the machining area quickly and orderly, avoiding secondary cutting problems caused by chip accumulation, reducing unnecessary friction between the tool and the chips, significantly improving chip removal efficiency, avoiding tool damage or surface vibration caused by poor chip removal, and thus improving the surface finish and dimensional accuracy of the machined surface.

[0037] 2. This application increases the cross-sectional area of ​​the tool body by setting a raised bottom surface of the groove to form a reinforcing rib structure, which significantly improves the bending / torsional rigidity of the tool, reduces the risk of tool deflection, chipping, and breakage, and significantly improves machining stability, thereby increasing tool life and supporting higher speeds and feed rates. At the same time, the raised bottom surface of the groove reduces the cross-sectional area of ​​the chip removal groove by less than 30%, thus retaining sufficient chip removal space, breaking through the mutual exclusion of "rigidity-chip removal" in traditional micro-tools, and ensuring smooth chip removal while increasing tool rigidity.

[0038] 3. The corrugated rake face and cutting edge disperse cutting stress through periodic concave and convex structures, suppress vibration and optimize chip morphology. Combined with the convex bottom surface of the concave arc groove, it guides the cutting fluid, enhances heat dissipation efficiency and reduces thermal damage.

[0039] The cutting tools employing the innovative groove design of this application combine high stability and long lifespan, enabling them to handle deep cavity milling and thin-walled microstructure machining of challenging materials such as titanium alloys and high-temperature alloys, achieving simultaneous improvement in surface roughness and precision. They have broad application prospects in the microelectronics, medical device, aerospace, and mold manufacturing industries. For example, in PCB milling, chip packaging structure milling, precision forming of endoscope components, micro-sensor cavity machining, and detailed engraving of optical lens cores and microfluidic chip molds, these tools demonstrate superior performance, becoming indispensable core tools in the field of micro-manufacturing. Attached Figure Description

[0040] To more clearly illustrate the technical solutions of the embodiments of this disclosure, the accompanying drawings of the embodiments will be briefly described below. Obviously, the drawings described below only relate to some embodiments of this disclosure and are not intended to limit this disclosure.

[0041] Figure 1 This is a schematic diagram of the micro-diameter end mill using a composite groove type in Example 1;

[0042] Figure 2 This is a schematic diagram of the blade body.

[0043] Figure 3 This is a cross-sectional view of the cutter body at the protrusion on the bottom surface of the groove;

[0044] Figure 4 This is a cross-sectional view of the cutter body along the axis of the cutter body at the protrusion on the bottom surface of the groove;

[0045] Figure 5 This is a schematic diagram of the micro-diameter end mill body using a composite groove type, as shown in Example 6.

[0046] Figure 6 This is a cross-sectional view of the cutter body at the protrusion on the bottom surface of the groove;

[0047] Figure 7 This is a schematic diagram of the body of a micro-diameter end mill using a composite groove type, as shown in Example 7.

[0048] Reference numerals: 100-tool body, 200-tool shank, 300-tool neck, 110-cutting edge, 120-chip groove, 10-rake face, 11-rake face protrusion, 12-rake face depression, 20-groove bottom, 30-corrugated cutting edge, 40-groove bottom protrusion. Detailed Implementation

[0049] To make the objectives, technical solutions, and advantages of the embodiments of this disclosure clearer, the technical solutions of the embodiments of this disclosure will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some, not all, of the embodiments of this disclosure. All other embodiments obtained by those skilled in the art based on the described embodiments of this disclosure without creative effort are within the scope of protection of this disclosure.

[0050] This application discloses a micro-diameter rotary cutting tool employing a composite groove design. The tool comprises: a cutting body with a diameter of 0.2 mm to 6 mm; a tool holder optionally used for direct or indirect connection to a machine tool; and a cutting neck optionally used to connect the cutting body and the tool holder. The cutting body has multiple cutting edges, and chip removal grooves are provided between adjacent cutting edges. Each chip removal groove has a rake face facing the cutting rotation direction, and also has a bottom surface connected to the rake face. The composite groove design of the chip removal groove is determined by the shapes of the rake face and the bottom surface. The rake face has a corrugated rake face protrusion and concavity, which includes one or more rake face protrusions and one or more rake face concave portions. The rake face protrusions and the rake face concave portions are arranged sequentially in the extension direction of the chip removal groove, so that the rake face intersects with the outer peripheral surface of the tool body to form the corrugated cutting edge of the cutting edge. One or more groove bottom surface protrusions are provided on the bottom surface of the groove, so that the cross-sectional area of ​​the tool body is locally increased in the area where the groove bottom surface protrusions are provided, and the groove bottom surface protrusions are provided so that the cross-sectional area of ​​the chip removal groove at that location is reduced by less than 30%.

[0051] In this application, "micro-diameter rotary cutting tool" refers to a rotary cutting tool with a tool body diameter greater than or equal to 0.2 mm and less than or equal to 6 mm. "Cross-section" refers to a cross-section perpendicular to the axis of the tool body. The cross-sectional area of ​​the tool body refers to the area of ​​the tool body material portion within the cross-section of the tool body. The cross-sectional area of ​​the chip removal groove refers to the area of ​​the chip removal groove portion within the cross-section of the tool body. The cross-sectional area of ​​the tool body and the cross-sectional area of ​​the chip removal groove together constitute the area of ​​the tool body cutting the outer circle of the rotary cutting.

[0052] In some embodiments, the diameter of the blade body is 0.5 mm to 6 mm, for example 0.6 mm to 5 mm, for example 0.8 mm to 4 mm, for example 1 mm to 3 mm, for example 0.8 mm to 3 mm.

[0053] This application incorporates a raised groove bottom surface to locally increase the cross-sectional area of ​​the tool body, thereby increasing the amount of material used and enhancing tool strength. Those skilled in the art can rationally select the shape based on the tool body diameter, core thickness, and length-to-diameter ratio. Typically, the raised groove bottom surface increases the cross-sectional area of ​​the tool body by more than 5%, 8%, 10%, or 15% compared to when the raised surface is not present. This application does not limit the specific shape of the raised groove bottom surface; the specified increase in cross-sectional area refers to the maximum range of increase after the raised groove bottom surface is incorporated, not that every location with the raised surface needs to reach this value. The number of raised groove bottom surfaces is closely related to the length-to-diameter ratio of the tool body; the larger the length-to-diameter ratio, the more raised surfaces should be. When the length-to-diameter ratio of the tool is less than 2, only one raised surface is needed to achieve good results.

[0054] This application limits the reduction in the cross-sectional area of ​​the chip removal groove caused by setting the bottom protrusion to be less than 30%, for example, less than 25%, less than 20%, or less than 15%. This application defines the reduction ratio of the cross-sectional area of ​​the chip removal groove as the maximum range of reduction after setting the bottom protrusion. An excessively large protrusion size will block the chip removal channel, thus adversely affecting chip removal. This application does not impose any particular restrictions on the choice of tool material; for example, it can be made of solid carbide, cermet, PCD, CBN, or other suitable materials.

[0055] The chip removal groove in this application can be a straight groove extending parallel to the axial direction of the tool body, an inclined groove extending obliquely along the axial direction of the tool body, or a spiral groove extending spirally along the axial direction of the tool body. The protrusions on the bottom surface of the groove can be provided simultaneously in all chip removal grooves, or only in some chip removal grooves. They can be provided simultaneously in the same position in different chip removal grooves, or in different positions in different chip removal grooves, so that the different protrusions are staggered.

[0056] The composite groove structure formed by the corrugated rake face and the raised bottom surface of the groove can work together to control the chip shape and optimize the chip removal path, thereby improving chip removal efficiency.

[0057] Existing micro-diameter end mills face a "rigidity-chip removal" mutual constraint. Only by increasing the size of the chip flute and providing sufficient chip removal space can chip retention be avoided. However, increasing the chip flute size inevitably means a decrease in tool strength, and the tool cannot obtain the required rigidity. For tools with a diameter of 6mm or more, the tool body can retain sufficient core thickness to obtain the required strength while also providing sufficient chip removal space, thus avoiding this mutual constraint. This mutual constraint is an important reason restricting the application of micro-diameter end mills in the field of precision manufacturing. However, the applicant unexpectedly discovered that although the convex design of the flute bottom reduces the cross-sectional area of ​​the chip removal groove locally, when the local cross-sectional area of ​​the chip removal groove is not significantly reduced, such as when the reduction value is less than 30% as specified in this application, it can accelerate chip removal and significantly improve chip removal efficiency in synergy with the corrugated rake face.

[0058] Unrestricted by theory, the mechanism by which the unique composite groove structure of this application improves chip removal efficiency may lie in the following: the corrugated cutting edge generates curved chips, and the concave and convex parts of the rake face intensify the periodic curling of the chips, providing deformation space for the curling process. Under the high-speed rotation of the tool, the chips naturally shrink into smaller curled structures. This curling mechanism not only reduces the contact area between the chips and the tool, but also creates favorable conditions for subsequent removal through geometric changes. When the curled chips enter the chip removal groove, the convex surface of the groove bottom forms micro-fulcrums that partially "lift" the chips away from the groove bottom surface. This transforms the originally attached and sliding chips into a jumping motion mode that alternates with the micro-fulcrums. Under the action of centrifugal force, the chips continuously shift outward. Under the high-speed rotation of the tool, the lifting action of the convex surface of the groove bottom plays a guiding role, quickly guiding the chips to the outer periphery of the tool and reducing the contact between the chips and the machined surface. The spatial phase coordination between the corrugated rake face and the raised bottom surface of the groove forms a propulsion structure similar to a "screw conveyor," which helps chips to be discharged along a predetermined path, reducing the risk of chip blockage and maintaining the continuity of the machining process. Furthermore, the corrugated rake face and the raised bottom surface of the groove create a constantly changing curved surface, continuously disturbing and altering the flow path of chips and coolant during tool rotation, breaking the flow balance and forming a pulsed propulsion that significantly improves chip removal efficiency. In addition, the unique groove-shaped composite structure reconstructs the chip removal flow field characteristics. The corrugated rake face diverts the cutting fluid into high-speed micro-vortices, enveloping curled chips to form a spiral motion. The raised bottom surface of the groove accelerates the fluid through a constricted flow channel, creating a low-pressure adsorption zone behind the raised surface. The synergy of these two factors qualitatively changes the material transport efficiency within the micro-scale chip removal channel, eliminating machining chatter caused by chip retention in traditional micro-diameter tools and achieving a breakthrough improvement in tool life by reducing frictional heat accumulation.

[0059] This application's unique composite groove design breaks through the traditional "rigidity-chip removal" mutual exclusion limitation of micro-tools. While significantly improving chip removal efficiency, it optimizes stress transmission paths by locally increasing the cross-sectional area of ​​the tool body through a raised bottom surface of the groove, thereby enhancing the overall rigidity of the tool. This not only strengthens the bending and torsional resistance of the micro-diameter end mill, reduces elastic deformation during machining, ensures dimensional accuracy, guarantees smooth chip removal, and reduces the rate of tool breakage, but its high rigidity structure also reduces the risk of chipping caused by chatter, exhibiting particularly excellent performance in side milling and deep cavity machining. It allows the tool to operate at higher spindle speeds and feed rates, thereby improving machining efficiency without sacrificing tool life.

[0060] This application also uses the periodic undulation structure of the corrugated rake face to disperse the concentrated cutting force to multiple contact areas. Combined with the dynamic cutting characteristics of the corrugated cutting edge, it effectively suppresses high-frequency vibration and resonance, improves machining stability and surface finish, and is especially suitable for precision machining scenarios with thin walls and micro-structures.

[0061] The corrugated rake face also expands the heat dissipation surface area, and combined with the convex bottom of the groove to guide the cutting fluid, it forms a highly efficient heat conduction and convection cooling mechanism. This design effectively reduces heat accumulation in the cutting edge area and delays the thermal softening of the tool material, making it suitable for continuous machining of high-heat-load materials such as titanium alloys and high-temperature alloys.

[0062] The collaborative design of the corrugated rake face and the raised bottom surface of the groove in this application gives the tool excellent chip removal performance, high rigidity, vibration resistance and thermal stability. It can meet the high dynamic load machining requirements such as deep cavity milling (high length-to-diameter ratio) and high feed side milling. It is especially suitable for fields with strict requirements for form and position accuracy and surface integrity, such as microelectronic packaging and medical implant threads.

[0063] In some embodiments, the height of the protrusion on the bottom surface of the chip removal groove accounts for 20% to 80% of the depth of the chip removal groove, for example, 20% to 60%, 40% to 60%, or 20% to 40%. In this application, the percentage of the height of the protrusion on the bottom surface of the chip removal groove to the depth of the groove refers to the percentage of the maximum height of the protrusion on the bottom surface of the groove to the depth of the chip removal groove. The maximum height of the protrusion on the bottom surface of the groove determines the maximum distance that the chips are partially lifted away from the bottom surface of the groove after entering the chip removal groove. It can be set within a wide range, as long as it is ensured that the protrusion is not too high, causing friction between the chips and the machined surface.

[0064] In some embodiments, the groove bottom surface protrusion has a convex arc-shaped top profile along the tool body axis, and the axial width of the groove bottom surface protrusion gradually increases from the top to the root, with the ratio of the top width to the root width being 0.3 to 0.8:1, for example, 0.4 to 0.7:1. That is, along the tool body axis, the bottom of the groove bottom surface protrusion is wider at the bottom and narrower at the top. This structural design makes the groove bottom surface protrusion stronger, better serving as a reinforcing rib, while providing a chip removal guiding surface, forming a better chip propulsion structure under high-speed tool rotation. Here, "top width" refers to the maximum axial width measured within the top range above two-thirds of the groove bottom surface protrusion height, and "root width" refers to any axial width measured within the range below one-third of the groove bottom surface protrusion height, as long as the ratio between the two axial widths meets the above range.

[0065] In some embodiments, when multiple groove bottom protrusions are provided, the ratio of the distance between adjacent groove bottom protrusions to the depth of the chip removal groove is 0.3 to 10, for example 0.5 to 10, for example 0.6 to 10, for example 0.3 to 8, for example 0.5 to 8, for example 0.6 to 8, for example 0.3 to 6, for example 0.5 to 6, for example 0.6 to 6, for example 0.3 to 5, for example 0.5 to 5, for example 0.6 to 5, for example 1 to 5, for example 1 to 10, for example 0.6 to 3. The larger the chip removal groove size, the larger the chip-holding space. An excessively large chip-holding space will reduce the speed and efficiency of chip flow out of the cutting area. A smaller chip removal groove size means a smaller chip removal distance, resulting in a higher speed and efficiency of chip flow out of the cutting area. However, an excessively small chip-holding space can easily lead to chip retention and blockage. In this application, the raised areas on the bottom of the chip groove "lift" the chips, preventing them from entering the bottom of the groove and thus reducing the chip removal distance. Areas without raised areas provide a larger chip-holding space, preventing chip retention and blockage. The distance between adjacent raised areas, including the area without raised areas, directly affects chip removal efficiency. If the ratio is too small, the raised areas are too dense, significantly reducing the chip-holding space and causing chip retention. If the ratio is too large, the raised areas are too dispersed, also reducing chip removal efficiency and negatively impacting tool rigidity. The groove design in this application combines the advantages of large and small chip-holding grooves, simultaneously improving both chip removal efficiency and tool rigidity. Those skilled in the art can select an appropriate range for the ratio of adjacent raised areas to the chip removal groove depth based on factors such as the tool's diameter and length-to-diameter ratio.

[0066] In this application, the "spacing between adjacent groove bottom surface protrusions" can be measured axially along the tool body, taking into account the specific shape of the groove bottom surface protrusions. For example, it can measure the axial distance between the roots of adjacent groove bottom surface protrusions, or the axial distance between the tops of adjacent groove bottom surface protrusions, or the axial distance between the top of one groove bottom surface protrusion and the root of an adjacent groove bottom surface protrusion. The "chip removal groove depth" is measured radially along the tool body, referring to the distance between the lowest point of the groove bottom surface and the outer circle of the tool body during cutting rotation.

[0067] In some embodiments, the groove bottom protrusions are simultaneously provided at corresponding positions in adjacent chip removal grooves, that is, the groove bottom protrusions are distributed along the circumference of the cutter body within the chip removal grooves, thereby increasing the core thickness of the cutter body. Locally increasing the core thickness of the cutter body in the area where the groove bottom protrusions are provided can achieve greater rigidity.

[0068] In some embodiments, the groove bottom protrusions at different positions along the axial direction of the cutter body have varying dimensions, causing the increase in core thickness at different positions along the axial direction of the cutter body to vary. For example, the groove bottom protrusions are designed to cause the local core thickness of the cutter body to gradually increase away from the shank, or the groove bottom protrusions are designed to cause the local core thickness of the cutter body to gradually increase towards the shank. This design allows the cutter body to have a higher length-to-diameter ratio and also provides a larger chip handling and removal space.

[0069] In some embodiments, the groove bottom surface protrusions are only provided within the range of increased core thickness of the cutter body. That is, within the cross-section of the cutter body, the groove bottom surface protrusions are all located within the range of the outer circle formed by the highest point of the groove bottom surface protrusion. This arrangement enhances the rigidity of the cutter body while retaining sufficient chip removal space. In a preferred embodiment, the tops of the groove bottom surface protrusions have the same circumscribed circle within the same cross-section of the cutter body. In a more preferred embodiment, the groove bottom surface protrusions are simultaneously provided at corresponding positions in adjacent chip removal grooves. That is, the groove bottom surface protrusions are distributed along the circumferential direction of the cutter body within the chip removal grooves, and the tops of the groove bottom surface protrusions have the same circumscribed circle within the same cross-section of the cutter body. With this arrangement, the highest points of the groove bottom surface protrusions at corresponding positions within the chip removal grooves collectively determine the increase in core thickness of the cutter body.

[0070] In some embodiments, the same bottom surface protrusion has a varying height, with its highest point located at the lowest point of the chip removal groove. The height of the bottom surface protrusion is measured with the bottom surface of the groove as the base. The varying height of the bottom surface protrusion can provide a better chip removal surface, and setting the bottom surface protrusion to have its maximum height at the lowest point of the concave arc surface of the chip removal groove can maximize the rigidity of the tool.

[0071] In some embodiments, the height of the raised bottom surface of the groove and the depth of the groove bottom surface change in opposite directions in a direction perpendicular to the tool body axis. The raised bottom surface extends from one side of the rake face away from the rake face within the chip evacuation groove. In this extension direction, the concave arc surface of the chip evacuation groove causes a change in the depth of the groove bottom surface, i.e., a change in the distance between the groove bottom surface and the outer circle of the tool body's cutting rotation. The height of the raised bottom surface and the depth of the groove bottom surface change in opposite directions, allowing the raised bottom surface to maximize tool rigidity while maintaining sufficient chip evacuation channels, and also achieving a shorter chip evacuation path, i.e., a better "lifting" effect on the chips, thus providing a superior chip evacuation surface.

[0072] In some embodiments, the same groove bottom surface protrusion has a convex arc-shaped top profile in a direction perpendicular to the tool body axis. That is, within a cross-section of the tool body, the groove bottom surface protrusion has a convex arc-shaped top profile, which can better improve tool rigidity while achieving a better "lifting" effect on chips and providing a superior chip removal surface.

[0073] In some embodiments, the aspect ratio of the micro-diameter rotary cutting tool is 5 or higher, or 6 or higher. Prior art micro-diameter end mills typically have an aspect ratio of less than 4; the rigidity-enhancing structure provided in this application allows the tool to have a higher aspect ratio.

[0074] In some embodiments, the top of the groove bottom protrusion is connected to the rake face, meaning the groove bottom protrusion extends to the rake face. The groove bottom protrusion extending to the rake face can better intercept the cutting fluid, guiding it to the cutting area, and also better cooperate with the corrugated rake face's concave and convex portions, thereby providing a closely fitted, varied surface for the flow of chips and coolant.

[0075] In some embodiments, the top of the raised bottom surface of the groove connects to the recessed portion of the rake face, meaning the raised bottom surface of the groove extends into the recessed portion of the rake face. This arrangement guides the coolant to the cutting edge region, reducing heat buildup in the cutting edge region and delaying the thermal softening of the tool material.

[0076] In some embodiments, the groove bottom protrusion extends downward or horizontally within the chip removal groove towards the cutting edge. That is, the groove bottom protrusion extends from the side away from the rake face towards the rake face and the cutting edge. "Extending downward" and "extending horizontally" describe the direction of extension of the groove bottom protrusion when the tool body is vertically positioned downwards. By extending downward or horizontally towards the cutting edge, the flow of chips and coolant can be enhanced. When extending downward, the cutting fluid can be guided to the cutting edge area, and the chips can be guided upward to flow out of the cutting area.

[0077] In some embodiments, the axial dimension of the protrusion on the bottom surface of the chip removal groove is less than or equal to half of the axial dimension of the bottom surface, for example, less than or equal to half but greater than or equal to one-fifth of the axial dimension of the bottom surface, or for example, less than or equal to one-third but greater than or equal to one-fifth of the axial dimension of the bottom surface. Here, both the axial dimension of the protrusion and the axial dimension of the bottom surface are measured in the axial direction of the tool body. That is, the proportion of the axial dimension of the protrusion on the bottom surface does not exceed one-half or one-third of the axial dimension of the bottom surface, and is not less than one-fifth of the axial dimension of the bottom surface. This arrangement ensures enhanced tool body rigidity while improving chip removal efficiency without significantly reducing the chip capacity of the chip removal groove, thus guaranteeing smooth chip removal.

[0078] In some embodiments, the wavelength of the corrugated cutting edge is 0.2 mm to 1.5 mm, and the amplitude is 5 μm to 0.5 mm. By precisely controlling the wavelength range between 0.2 mm and 1.5 mm (e.g., 0.2 mm to 1 mm) and the amplitude range between 5 μm and 0.5 mm (e.g., 5 μm to 0.1 mm, 5 μm to 0.15 mm, 5 μm to 0.18 mm), a periodic corrugated cutting edge structure is formed. This not only effectively modulates the cutting force, significantly reducing the fluctuation amplitude of the cutting force, but also significantly enhances the heat dissipation performance of the micro-area and significantly reduces the cutting temperature.

[0079] This application also discloses a micro-diameter rotary cutting tool employing the aforementioned groove shape, such as a micro-diameter end mill.

[0080] This application also discloses a method for preparing the aforementioned micro-diameter rotary cutting tool, wherein the groove shape is prepared by a machining method that does not produce thermal damage.

[0081] In some embodiments, the groove shape is prepared using a femtosecond pulsed laser processing method.

[0082] This application also discloses a method for using the aforementioned micro-diameter rotary cutting tool, characterized by comprising the following steps:

[0083] Chip removal grooves are ground into the rotary cutting tool blank to form the rake face and the bottom surface of the groove.

[0084] The groove shape is formed by machining a corrugated rake face with concave and convex parts on the rake face and a groove bottom protrusion on the groove bottom surface using a femtosecond pulsed laser processing method.

[0085] The scope described above can be used alone or in combination. The following examples will make this application easier to understand.

[0086] Example

[0087] Example 1

[0088] This embodiment provides a micro-diameter end mill using a composite groove design, such as... Figures 1 to 4 As shown, the micro-diameter milling cutter includes:

[0089] Blade body 100,

[0090] Tool holder 200 for connection with machine tools

[0091] The cerf 300 is used to connect the blade body and the handle.

[0092] The blade body is made of a single piece of cemented carbide, with a diameter of 2mm and a length of 4mm.

[0093] The tool body 100 has four cutting edges 110 arranged along its circumference, and chip removal grooves 120 extending obliquely along the axial direction of the tool body are provided between adjacent cutting edges. The depth of the chip removal grooves is 0.3 mm.

[0094] The chip removal groove 120 has a surface facing the cutting rotation direction, which is the rake face 10.

[0095] The chip removal groove 120 also has a concave arc surface connected to the rake face 10 and extending along the axial direction of the tool body, which is the bottom surface 20 of the groove.

[0096] The composite groove shape of the chip removal groove is determined by the shapes of the rake face 10 and the groove bottom surface 20, wherein,

[0097] Each of the four rake faces has a corrugated rake face protrusion and concavity, which includes three rake face protrusions 11 and two rake face concavities 12. The rake face protrusions and the rake face concavities are arranged sequentially in the extending direction of the chip removal groove, so that the rake face intersects with the outer peripheral surface of the tool body to form the corrugated cutting edge 30 of the cutting edge.

[0098] Each of the four groove bottom surfaces 20 is provided with two spaced groove bottom surface protrusions 40, thereby increasing the cross-sectional area of ​​the cutter body locally in the area where the groove bottom surface protrusions are provided, and the groove bottom surface protrusions are provided so that the cross-sectional area of ​​each chip removal groove at that location is reduced by less than 30%.

[0099] The groove bottom protrusions are simultaneously provided at corresponding positions in adjacent chip removal grooves, that is, the groove bottom protrusions are distributed along the circumference of the cutter body in the chip removal groove, thereby increasing the core thickness of the cutter body.

[0100] Figure 3 The diagram shows a cross-sectional view perpendicular to the tool body axis, taken at the highest point of the protrusion on the bottom surface of the groove at the end. The dashed circle represents the outer circle of the tool body during cutting. Figure 3 In the cross-section shown, the raised bottom surface of the groove increases the area of ​​the blade material by more than 5% compared to when the raised bottom surface of the groove is not provided, and the raised bottom surface of the groove reduces the area of ​​the blank part inside the dashed circle by about 25%.

[0101] exist Figure 3 In the cross-section shown, the bottom surface of the groove protrudes with a convex arc-shaped top profile. The maximum height of the bottom surface protrusion accounts for 40% of the depth of the chip removal groove, and its highest point is located at the lowest point of the concave arc surface.

[0102] Figure 4 A cross-sectional view along the axis of the cutter body is shown at the highest point of the protrusion on the bottom surface of the groove at the end. Figure 4As shown, the groove bottom surface protrusion has a convex arc-shaped top profile, and the axial width of the groove bottom surface protrusion gradually increases from the top to the root, with the ratio of the top width to the root width ranging from 0.6 to 0.8:1.

[0103] exist Figure 4 In the cross-section shown, the ratio of the distance between the two bottom protrusions of the groove to the depth of the chip removal groove is 5.

[0104] The same groove bottom surface protrusion has a varying height, such as Figure 2 As shown, the top of the protrusion on the bottom surface of the groove is connected to the recessed portion of the front cutting face, that is, the protrusion on the bottom surface of the groove extends into the recessed portion of the front cutting face.

[0105] When the cutter body is vertically positioned downwards, the protrusion on the bottom surface of the groove extends downwards at an angle toward the cutting edge within the chip removal groove. That is, the protrusion on the bottom surface of the groove extends upwards at an angle away from the rake face within the chip removal groove.

[0106] The wave pattern of the cutting edge has a wavelength of 1 mm and an amplitude of 0.18 mm.

[0107] Example 2

[0108] The overall structure of the composite groove micro-diameter end mill in this embodiment is basically the same as that in Embodiment 1. The difference is that the diameter of the cutter body is 1 mm. By setting the bottom surface of the groove to be raised, the cross-sectional area of ​​the cutter body at the highest point of the bottom surface of the groove is increased by more than 8%, and the cross-sectional area of ​​each chip removal groove at that point is reduced by about 30%. The depth of the chip removal groove is 0.15 mm. The maximum height of the bottom surface of the groove is 30% of the depth of the chip removal groove. In the axial direction of the cutter body, the ratio of the distance between adjacent bottom surface protrusions to the depth of the chip removal groove is 3.

[0109] Example 3

[0110] The overall structure of the composite groove micro-diameter end mill in this embodiment is basically the same as that in Embodiment 1, except that: the diameter of the cutter body is 4mm, and by setting the bottom surface of the groove to protrude, the cross-sectional area of ​​the cutter body at the highest point of the bottom surface of the groove is locally increased by more than 5%, and the cross-sectional area of ​​each chip removal groove at that point is reduced by about 20%, the depth of the chip removal groove is 0.6mm, the maximum height of the bottom surface of the groove is 30% of the depth of the chip removal groove, and the ratio of the distance between adjacent bottom surface protrusions to the depth of the chip removal groove in the axial direction of the cutter body is 1.

[0111] Example 4

[0112] The overall structure of the composite groove micro-diameter end mill in this embodiment is basically the same as that in Embodiment 1. The difference is that the diameter of the cutter body is 6mm. By setting the bottom surface of the groove to be raised, the cross-sectional area of ​​the cutter body at the highest point of the bottom surface of the groove is increased by more than 5%, and the cross-sectional area of ​​each chip removal groove at that point is reduced by about 25%. The depth of the chip removal groove is 1.5mm. The maximum height of the bottom surface of the groove is 20% of the depth of the chip removal groove. In the axial direction of the cutter body, the ratio of the distance between adjacent bottom surface protrusions to the depth of the chip removal groove is 0.5.

[0113] Example 5

[0114] The overall structure of the composite groove micro-diameter end mill in this embodiment is basically the same as that in Embodiment 1. The difference is that the diameter of the cutter body is 6mm. By setting the bottom surface of the groove to be raised, the cross-sectional area of ​​the cutter body at the highest point of the bottom surface of the groove is increased by more than 5%, and the cross-sectional area of ​​each chip removal groove at that point is reduced by about 25%. The depth of the chip removal groove is 1.5mm. The maximum height of the bottom surface of the groove is 20% of the depth of the chip removal groove. In the axial direction of the cutter body, the ratio of the distance between adjacent bottom surface protrusions to the depth of the chip removal groove is 0.3.

[0115] Cutting Experiment 1

[0116] Thin-walled electronic product parts made of titanium alloy TC4 were machined using the cutting tools described in Examples 1 to 5 of this application. The machine tool used was a Beijing Jingdiao vertical machining center, and the machining method was keyway milling. The machining life (based on the number of workpieces machined) and surface finish were measured. A traditional micro-diameter end mill, which is the same as the examples but without the composite groove type, was used as a control. The machining test results are shown in Table 1 below:

[0117] Table 1

[0118]

[0119] The cutting tool using the technical solution of this application has smoother chip removal during the cutting process. Compared with the comparative machining process, the machining vibration caused by chip retention is significantly reduced. As can be seen from the above cutting test data, the tool life and product surface finish of the embodiment of this application are improved to varying degrees.

[0120] Example 6

[0121] This embodiment provides a micro-diameter end mill using a composite groove design, such as... Figures 5 to 6 As shown, the micro-diameter rotary cutting tool includes:

[0122] Blade body,

[0123] Tool holders for connection to machine tools

[0124] The blade neck is used to connect the blade body and the handle.

[0125] The blade body 100 is made of a single piece of cemented carbide, with a diameter of 0.8 mm and a length of 3 mm.

[0126] The tool body 100 has four cutting edges 110 arranged along its circumference, and chip removal grooves 120 extending along the axial direction of the tool body are arranged between adjacent cutting edges. The chip removal grooves are straight grooves.

[0127] The chip removal groove 120 has a surface facing the cutting rotation direction, which is the rake face 10.

[0128] The chip removal groove 120 also has a concave arc surface connected to the rake face 10 and extending along the axial direction of the tool body, which is the bottom surface 20 of the groove.

[0129] The composite groove shape of the chip removal groove is determined by the shapes of the rake face 10 and the groove bottom surface 20, wherein,

[0130] Each of the four rake faces has a corrugated rake face protrusion and concavity, which includes three rake face protrusions 11 and two rake face concavities 12. The rake face protrusions and the rake face concavities are arranged sequentially in the extending direction of the chip removal groove, so that the rake face intersects with the outer peripheral surface of the tool body to form the corrugated cutting edge 30 of the cutting edge.

[0131] Three spaced groove bottom protrusions 40 are provided at the same position on each of the four groove bottom surfaces 20, thereby increasing the cross-sectional area of ​​the cutter body locally in the area where the groove bottom protrusions are provided, and the groove bottom protrusions are provided so that the cross-sectional area of ​​each chip removal groove at that location is reduced by less than 30%.

[0132] The groove bottom protrusions are simultaneously provided at the same position in adjacent chip removal grooves, that is, the groove bottom protrusions are distributed along the circumference of the cutter body within the chip removal grooves, thereby increasing the core thickness of the cutter body. Furthermore, the groove bottom protrusions are only provided within the range of increased core thickness, and the three groove bottom protrusions have varying dimensions, causing the core thickness increase value to vary at different positions along the axial direction of the cutter body. Figure 6 The diagram shows a cross-sectional view perpendicular to the tool body axis, taken at the highest point of the protrusion on the bottom surface of the groove located in the middle. The outer large dashed circle represents the outer circle of the tool body's cutting rotation, and the inner small dashed circle represents the core thickness without the protrusion. Figure 6In the cross-section shown, the raised bottom surface of the groove increases the area of ​​the tool body material by more than 10% compared to when the groove bottom surface is not raised, and reduces the area of ​​the blank portion within the dashed circle by approximately 25%. The raised bottom surface near the blade neck increases the area of ​​the tool body material by more than 8% compared to when the groove bottom surface is not raised, and reduces the cross-sectional area of ​​the chip removal groove at that location by approximately 20%. The raised bottom surface at the end increases the area of ​​the tool body material by more than 5% compared to when the groove bottom surface is not raised, and reduces the cross-sectional area of ​​the chip removal groove at that location by approximately 15%.

[0133] exist Figure 6 Within the cross-section shown, the convex bottom surface of the groove has a convex arc-shaped top profile. The maximum height of the convex bottom surface is 40% of the depth of the chip removal groove. The top of the convex bottom surface has the same circumcircle within the same cross-section of the tool body. Figure 6 The central dashed circle and the highest point of the groove bottom surface together determine the increase in the core thickness of the cutter body, that is, from the smallest range of the inner dashed circle to the range of the central dashed circle.

[0134] Along the axial direction of the cutter body, the groove bottom surface protrusion has a convex arc-shaped top profile, and the axial width of the groove bottom surface protrusion gradually increases from the top to the root, with the ratio of its top width to its root width ranging from 0.3 to 0.8:1.

[0135] In the section along the axis of the tool body at the highest point of the convex bottom surface of the middle groove, the ratio of the distance between the two convex bottom surfaces to the depth of the chip removal groove is 3.

[0136] like Figure 5 As shown, the top of the groove bottom protrusion is connected to the front cutting face, that is, the groove bottom protrusion extends to the front cutting face.

[0137] When the cutter body is vertically positioned downwards, the bottom surface of the groove protrudes horizontally within the chip removal groove towards the cutting edge, that is, the bottom surface of the groove protrudes from one side of the rake face in the chip removal groove in a direction away from the rake face.

[0138] Along the axial direction of the cutter body, the axial dimension of the protrusion on the bottom surface of the chip removal groove is less than half of the axial dimension of the bottom surface of the groove.

[0139] The wave pattern of the cutting edge has a wavelength of 2 mm and an amplitude of 0.18 mm.

[0140] Example 7

[0141] This embodiment provides another micro-diameter end mill using a composite groove design, such as... Figure 7As shown, the difference between its structure and that of Embodiment 6 is that the diameter of the blade body 100 is 0.8 mm and the length is 1.6 mm. The chip removal groove 120 is an inclined groove, and each chip removal groove has a groove bottom surface protrusion 40 on the groove bottom surface 20 at its central position. The groove bottom surface protrusion increases the area of ​​the blade body material portion by more than 8% compared to when the groove bottom surface protrusion is not provided, and the groove bottom surface protrusion reduces the cross-sectional area of ​​the chip removal groove at that location by about 20%. In the axial direction of the blade body, the axial dimension of the groove bottom surface protrusion on the groove bottom surface of the chip removal groove is less than one-fifth of the axial dimension of the groove bottom surface. The wavelength of the corrugated cutting edge is 0.8 mm and the amplitude is 0.1 mm.

[0142] Cutting Experiment 2

[0143] Thin-walled titanium alloy TC4 parts were machined using the cutting tools described in Examples 6 and 7 of this application. The machine tool was a Beijing Jingdiao vertical machining center. The machining method was keyway milling. The machining life (based on the number of workpieces machined) and surface finish were measured. A micro-diameter end mill with the same rake face and cutting edge as Example 6 but without a raised bottom surface was used as Comparative Example 6. A conventional micro-diameter end mill with the same rake face and cutting edge as Example 6 but without a composite groove type was used as Comparative Example 7. The machining test results are shown in Table 2 below.

[0144] Table 2

[0145] detection indicators Processing life (pieces) Surface finish Ra (μm) Example 6 21 0.8 Example 7 16 0.8 Comparative Example 6 12 1.6 Comparative Example 7 6 2.2

[0146] The cutting tool using the technical solution of this application has smoother chip removal during the cutting process. Compared with the comparative machining process, the machining vibration caused by chip retention is significantly reduced. As can be seen from the above cutting test data, compared with traditional milling cutters and micro-diameter milling cutters with only corrugated rake faces, the cutting tool of this application has a raised bottom surface of the groove, which locally reduces the cross-sectional area of ​​the chip removal groove, but improves the machining life and product surface finish to varying degrees. The cutting tool has both high stability and long life.

[0147] The above description is merely an exemplary embodiment of this disclosure and is not intended to limit the scope of protection of this disclosure, which is determined by the appended claims.

Claims

1. A micro-diameter rotary cutting tool having a composite flute, characterized in that, the micro-diameter rotary cutting tool comprises: a tool body having a diameter of 0.2 mm to 6 mm, an optional shank for direct or indirect connection to a machine tool, an optional neck for connecting the tool body and the shank, a plurality of cutting edges are provided on the tool body, and a chip flute is provided between adjacent cutting edges, the chip flute has a rake surface facing the direction of cutting rotation, which is a rake surface, the chip flute also has a flute bottom surface connected to the rake surface, the composite flute is determined by the shape of the rake surface and the flute bottom surface, wherein, the rake surface has a corrugated rake surface concave-convex portion, which includes one or more rake surface convex portions and one or more rake surface concave portions, the rake surface convex portions and the rake surface concave portions are arranged in sequence in the extension direction of the chip flute, so that the rake surface intersects with the outer peripheral surface of the tool body to form a corrugated edge of the cutting edge, one or a plurality of flute bottom surface convexes are arranged on the flute bottom surface, so that the cross-sectional area of the tool body is locally increased in the area where the flute bottom surface convex is arranged.

2. The micro-diameter rotary cutting tool of claim 1, wherein, The height of the flute bottom surface convex is 20% to 80%, for example 20% to 60%, for example 40% to 60% of the depth of the chip flute.

3. The micro-diameter rotary cutting tool of claim 1, wherein, In the axial direction of the tool body, the flute bottom surface convex has a convex arc-shaped top profile, and the axial width of the flute bottom surface convex gradually increases from the top to the root, and the ratio of the top width to the root width is 0.3-0.8:1, for example 0.4-0.7:

1.

4. The micro-diameter rotary cutting tool of claim 1, wherein, In the case of arranging a plurality of flute bottom surface convexes, the distance between adjacent flute bottom surface convexes is 0.3 to 10, for example 0.5 to 10, for example 0.6 to 10 times the depth of the chip flute.

5. The micro-diameter rotary cutting tool of claim 1, wherein, The flute bottom surface convex is arranged at the corresponding position of adjacent chip flutes at the same time, that is, the flute bottom surface convex is distributed along the circumferential direction of the tool body in the chip flute, so that the core thickness of the tool body is increased.

6. The micro-diameter rotary cutting tool of claim 1, wherein, In the direction perpendicular to the axis of the tool body, the same flute bottom surface convex has a convex arc-shaped top profile.

7. The micro-diameter rotary cutting tool of claim 1, wherein, The top of the flute bottom surface convex is connected to the rake surface, that is, the flute bottom surface convex extends to the rake surface.

8. The micro-diameter rotary cutting tool of claim 1, wherein, The top of the flute bottom surface convex is connected to the rake surface concave portion, that is, the flute bottom surface convex extends into the rake surface concave portion.

9. The micro-diameter rotary cutting tool of claim 1, wherein, The flute bottom surface convex extends downwardly or horizontally in the chip flute towards the direction of the edge.

10. The micro-diameter rotary cutting tool of claim 1, wherein, In the axial direction of the tool body, the axial dimension of the flute bottom surface convex arranged on the flute bottom surface of the chip flute is less than or equal to half of the axial dimension of the flute bottom surface, for example less than or equal to one third of the axial dimension of the flute bottom surface.

11. The micro-diameter rotary cutting tool of claim 1, wherein, The wavelength of the corrugated edge is 0.2 mm to 1.5 mm, and the amplitude is 5 μm to 0.5 mm.

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