A round-arc-shaped edge root milling cutter

Abstract

The application discloses a kind of round-arc blade clearance milling cutter, belong to cutting tool technical field, including tool tip part, tool body part and chip pocket. Tool tip part includes tool tip rake face, tool tip end face, tool tip relief face and tip. Tool body part includes tool body rake face, tool body end face and tool body relief face. Chip pocket 3 and tool tip relief face and cutting face mutually link. The structure is designed by tool tip inclination, blade round-arc and end blade partition, realizes the collaborative promotion of root cleaning machining capacity, tool tip impact resistance and chip removal stability, to solve the problem that traditional flat-end milling cutter is difficult to consider sharp angle protection and root cleaning machining simultaneously. The scheme cooperatively designs the spatial geometric relationship between tool tip part, tool body part and chip pocket, forms a composite cutting structure with root cleaning capacity and structural strength in the tool tip area.

Description

Technical Field

[0001] This invention belongs to the field of cutting tool technology, specifically an arc-shaped end mill with a clearing edge. Background Technology

[0002] In the field of metal cutting, flat end mills not only perform material removal tasks in the machining of box-shaped, disc-shaped, and complex cavity parts, but also directly affect the dimensional accuracy, contour quality, and machining efficiency of the machined surface. Among existing flat end mills, a common structural form is the "straight-line raised" corner protection type. This structure increases the wedge angle strength at the tip of the end teeth by radially retracting the tip region towards the center of the cutter body, thereby enhancing the tip's resistance to chipping and improving tool durability to some extent.

[0003] However, while traditional "lifting" structures can effectively protect the tip angle of the end teeth, the outer edge of the end teeth does not extend completely to the theoretical right angle position. This prevents the tool from achieving true root clearing when machining the bottom of the cavity or the root of the right angle. An unmachined area of ​​approximately 0.03mm to 0.08mm typically remains at the bottom of the workpiece, and this amount varies with the tool diameter. In precision machining applications requiring high root clearing, a secondary machining operation with a root clearing end mill is often necessary, increasing tool change time and machining costs, and reducing machining efficiency.

[0004] Secondly, although existing root-cleaning flat cutters that can achieve root-cleaning function have eliminated the "lifting" structure, the end teeth of this type of tool lack a retraction structure, resulting in a reduced wedge angle in the tool tip area and an excessively sharp local structure. During the cutting process, the tool tip is prone to rapid wear after being subjected to large impact loads and thermal stresses, and in severe cases, even tooth breakage may occur, leading to a shortened tool life.

[0005] Therefore, existing flat end mills generally suffer from the problem of balancing sharp corner protection and root clearing capability in their structural design, and usually have to make a trade-off between the two. Summary of the Invention

[0006] The purpose of this invention is to provide an arc-shaped cutting edge end mill to solve the problems mentioned in the prior art.

[0007] A circular arc-shaped end mill is provided, comprising: The cutting tip includes a front angle face, a tip face, a back angle face, and a tip. The radius of rotation D of the tip is the maximum radius of rotation of the cutting tip. The tip is the earliest point of contact between the milling cutter and the workpiece during cutting. The milling cutter has a radial plane Q1 passing through the earliest point of contact. The tangent at any point on the tip face forms an angle α with the radial plane of the milling cutter, and the angle α is 3°-18°. The cutter body includes a front face, an end face, and a rear face. The front face and rear face intersect to form a cutting edge. The milling cutter has radial planes Q1 and Q2 passing through the two endpoints of the cutting edge. The vertical distance L1 between Q1 and Q2 is 0.01D-0.05D. The front face and the front face of the cutter body form a cutting face. The front face of the cutter tip intersects with the cutting face to form a first end edge. The end face of the cutter body intersects with the cutting face to form a second end edge. The two endpoints of the first end edge form rotating circular tangents S1 and S2, respectively. The vertical distance L2 between S1 and S2 is 0.02D-0.3D. The chip groove is connected to the back face of the cutting tip and the cutting face. The milling cutter has a radial plane Q3 passing through the intersection of the first end cutting edge and the second end cutting edge, and a radial plane Q4 passing through the chip groove and the closest point to the radial plane Q1. The vertical distance L3 between Q3 and Q4 is 0.005-0.015D.

[0008] As a further aspect of the present invention: a first cutting edge angle γ1 is formed between the first end cutting edge and the radial plane of the milling cutter, and γ1 is 0°-3°; a second cutting edge angle γ2 is formed between the second end cutting edge and the radial plane of the milling cutter, and γ2 is 7°-12°.

[0009] As a further aspect of the present invention: the tangent at the tip of the cutting edge forms an angle of β degrees with the radial plane of the milling cutter, and the angle β is 70°-90°.

[0010] As a further aspect of the present invention: the tangent at the tip of the cutting edge forms an angle of β degrees with the radial plane of the milling cutter, and the angle β is 70°-85°.

[0011] As a further aspect of the present invention: the tangent at the tip of the cutting edge forms an angle of β degrees with the radial plane of the milling cutter, and the β angle is 75°-80°.

[0012] As a further aspect of the present invention: the cutting edge is formed by the intersection of the back angle face of the cutting tip and the chip groove. The cutting edge extends in a spiral shape in the circumferential direction of the milling cutter with a spiral angle of 30°-45°. The cutting edge and the cutting edge are connected by an arc. The spiral angles of the multiple cutting edges in the circumferential direction of the milling cutter are not equal.

[0013] As a further aspect of the present invention: the difference in helix angle of each cutting edge in the circumferential direction of the milling cutter φ satisfies 0.5°≤| φ|≤5°.

[0014] As a further aspect of the present invention: the radial plane of the milling cutter intersects with the back angle face of the cutter tip to form a helical section, and the rotation radius of the helical section gradually decreases in the direction from the chip groove to the back angle face of the cutter body.

[0015] As a further aspect of the present invention: in the direction from the chip groove to the back angle face of the cutter body, the back angle face of the cutter tip is composed of multiple sub-helical surfaces arranged in sequence, and the radial plane of the milling cutter intersects with the multiple sub-helical surfaces to form multiple sub-helical lines. A single sub-helical line extends in a straight line, and two adjacent sub-helical lines have an abrupt transition.

[0016] As a further aspect of the present invention: a tooth pitch angle θ is formed between two adjacent second end edges. i (i=1, 2, ..., N, where N is the number of teeth on the milling cutter), multiple tooth pitch angles θ in the circumferential direction of the milling cutter. i They are not equal.

[0017] As a further aspect of the present invention: tooth pitch angle θ i Satisfy: θ min ≥0.8 (360° / N), θ max ≤1.2 (360° / N), and all θ i The sum is 360°.

[0018] Compared with the prior art, the beneficial effects of the present invention are as follows: The continuous arc-shaped spatial structure of the cutting edge allows the root-clearing area to extend to the theoretical right angle position, thereby reducing the residue at the bottom of the cut. The tip face adopts an inclined structure with a specific angle to the radial plane, ensuring the sharpness of the cut while optimizing the wedge angle to guarantee structural strength, reduce instantaneous impact load, and improve chipping resistance. By constraining the relative relationship between the dimensions of each part of the tip and the milling cutter diameter, and by forming a segmented cutting layout through the first and second end edges, the strength of the end teeth is guaranteed.

[0019] Overall, this structure achieves a synergistic improvement in corner clearing capability, tip impact resistance, and chip removal stability through tip tilting, cutting edge rounding, and end-edge partitioning design, thus solving the problem that traditional flat-end mills cannot simultaneously achieve both corner protection and corner clearing. This solution collaboratively designs the spatial geometry between the tip, body, and chip grooves, forming a composite cutting structure in the tip region that combines corner clearing capability with structural strength. Attached Figure Description

[0020] To more clearly illustrate the technical solutions in the embodiments of this drawing 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 only some embodiments of this drawing. For those skilled in the art, other drawings can be obtained based on the structures shown in these drawings without creative effort.

[0021] Figure 1This is a schematic diagram of the overall structure of the root clearing end mill of the present invention; Figure 2 This is a partial structural schematic diagram of the root clearing end mill of the present invention; Figure 3 This is one of the structural schematic diagrams of a single helical blade of the present invention; Figure 4 This is a second schematic diagram of the structure of a single helical blade of the present invention; Figure 5 This is one of the schematic diagrams of the end face structure of the end mill of the present invention; Figure 6 This is the third schematic diagram of the structure of a single helical blade of the present invention; Figure 7 This is the fourth schematic diagram of the structure of a single helical blade of the present invention; Figure 8 This is the second schematic diagram of the end face structure of the root clearing milling cutter of the present invention; Figure 9 This is the fifth schematic diagram of the structure of a single helical blade of the present invention.

[0022] In the diagram: 1. Tool tip; 11. Tool tip rake face; 12. Tool tip face; 13. Tool tip clearance face; 131. Sub-helix face; 14. Tip; 2. Tool body; 21. Tool body rake face; 22. Tool body end face; 23. Tool body clearance face; 3. Chip groove; 4. Cutting face; 51. First end edge; 52. Second end edge; 61. Cutting edge; 62. Cutting edge. Detailed Implementation

[0023] To make the objectives, technical solutions, and advantages of this application clearer, the application is described and illustrated below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative and not intended to limit the scope of this application. All other embodiments obtained by those skilled in the art based on the embodiments provided in this application without inventive effort are within the scope of protection of this application.

[0024] Obviously, the accompanying drawings described below are merely some examples or embodiments of this application. Those skilled in the art can apply this application to other similar scenarios based on these drawings without any inventive effort. Furthermore, it is understood that although the efforts made in this development process may be complex and lengthy, for those skilled in the art related to the content disclosed in this application, any changes to design, manufacturing, or production based on the technical content disclosed in this application are merely conventional technical means and should not be construed as insufficient disclosure of the content of this application.

[0025] However, there may be instances where unnecessary detailed descriptions are omitted. For example, detailed descriptions of well-known matters or repetitive descriptions of essentially the same structures may be omitted. This is to avoid unnecessarily lengthy descriptions and to facilitate understanding by those skilled in the art. Furthermore, the accompanying drawings and the following description are provided to enable those skilled in the art to fully understand this application and are not intended to limit the subject matter of the claims.

[0026] Please see Figures 1-2 As shown in the embodiment of the present invention, an arc-shaped end mill with a clearing edge is provided. The end mill includes two parts: a cutter head and a cutter shank. The cutter head has multiple helical cutting edges distributed in the circumferential direction. Each helical cutting edge specifically includes a tip 1, a body 2, and a chip groove 3.

[0027] The blade tip 1 includes a front angle face 11, a tip face 12, a rear angle face 13, and a tip 14. The tip 14 is the intersection of the front angle face 11, the tip face 12, and the rear angle face 13.

[0028] The cutter body 2 includes a rake face 21, an end face 22, and a clearance face 23. The rake face 11 of the cutter tip connects with the rake face 21 to form the cutting face 4 of the end tooth. The tip face 12 connects with the end face 22 to form the cutting end face of the milling cutter. The clearance face 13 connects with the clearance face 23 to form the cutting side face of the milling cutter.

[0029] The tip clearance face 13 and the body clearance face 23 are connected to each other and together serve as the helical side surface of the helical cutting edge. In a single helical cutting edge, the chip groove 3 is connected to the tip clearance face 13 and the cutting face 4 respectively, and the whole extends in a helical shape between two adjacent helical cutting edges.

[0030] The radius of rotation D of the tip 14 is set to the maximum radius of rotation of the tip 1, and serves as the earliest point of contact between the milling cutter and the workpiece during cutting, so that the cutting load is initially borne by the tip 14. In addition, the milling cutter is formed with a radial plane Q1 passing through the earliest point of contact.

[0031] This structure creates a 61 end mill with an arc-shaped cutting edge that balances end milling capability and tip strength. The core of this design is to reconstruct the end tooth cutting trajectory through the spatial geometric relationship between the tip part 1, the body part 2, and the chip groove 3. This allows the tool to achieve end milling at a near-theoretical right angle position while avoiding the problem of excessively sharp tips in traditional end mills.

[0032] Specifically, please refer to Figures 1-4As shown, the tangent at any point on the tip face 12 forms an angle of α degrees with the radial plane of the milling cutter, with α ranging from 3° to 18°. Therefore, the tip face 12 is not a traditional, completely horizontal structure, but rather forms a slightly inclined spatial slope. This structure allows the tip 1 to gradually cut into the material as it approaches the bottom corner of the workpiece, rather than making instantaneous, overall contact, thereby reducing the concentration of impact loads and improving the chipping resistance of the tip area. Simultaneously, this inclined structure allows the tip face 12 to extend further into the theoretical root-cleaning area, thus avoiding the bottom residue problem caused by the tip retraction in traditional "lift-up" structures.

[0033] It should be noted that since the tip 14 is the earliest point of contact between the milling cutter and the workpiece during cutting, the inclined surface extends from the tip 14 toward the tool holder, that is, the cutting surface extends away from the feed direction of the milling cutter.

[0034] The rake face 11 and clearance face 13 of the cutting tip meet to form the cutting edge 61. In addition to the cutting edge 61, the clearance face 13 of the cutting tip meets the chip groove 3 to form the cutting edge 62. The cutting edge 62 extends spirally along the milling cutter and has a specific helix angle. Importantly, the cutting edge 61 itself does not extend in a straight line, but forms a spatial arc structure with a certain span, and there is an arc transition between the cutting edge 61 and the cutting edge 62.

[0035] The rounded cutting edge 61 can disperse the cutting load along the cutting length direction, reduce local stress concentration, and create a gradual transition between the tip 1 and the body 2, avoiding the formation of a sharp and weak area at the tip of the traditional root clearing flat knife.

[0036] Please see Figure 4 As shown, more specifically, the milling cutter forms radial planes Q1 and Q2 passing through the two endpoints of the cutting edge 61, and the vertical distance L1 between Q1 and Q2 is 0.01D-0.05D.

[0037] The vertical distance L1 corresponds to the axial spatial unfolding length of the cutting edge 61, determining the degree of lifting and transition range of the arc-shaped cutting edge 61. If L1 is too small, the basic solid part supporting the cutting edge 61 and the tip 14 is insufficient, meaning the basic load-bearing capacity of the cutting edge 61 and the tip 14 is insufficient. If L1 is too large, the length of the cutting edge 61 is too large, resulting in an increased time for the workpiece load to be transferred from the cutting edge 61 to the cutting edge 62, and an increased impact and friction load on the cutting edge 61. In other words, both excessively large and small L1 can lead to localized chipping of the tool tip.

[0038] Please see Figure 2 and Figure 5As shown, the tip face 12 of the tool meets the cutting face 4 to form the first end edge 51, and the end face 22 of the tool body meets the cutting face 4 to form the second end edge 52. The two endpoints of the first end edge 51 form rotating circular tangents S1 and S2 respectively, and the vertical distance L2 between S1 and S2 is 0.02D-0.3D.

[0039] This dimension determines the effective radial cutting span of the first end cutting edge 51, essentially corresponding to the transition width between the root clearing cutting area and the main cutting area. When L2 is small, the first end cutting edge 51 is short, the cutting area at the tool tip is too concentrated, which can easily lead to excessive local load on the tool tip; at the same time, the transition between the first end cutting edge 51 and the second end cutting edge 52 is too rapid, resulting in a significant change in cutting force. Conversely, when L2 is too large, it means that the tool tip area occupies too large a proportion, the initial amount of cutting at the front end of the tool tip 1 is too large, the cutting bluntness of the milling cutter increases, and the cutting effect of the milling cutter is weakened.

[0040] Please see Figure 2 and Figure 6 As shown, the milling cutter has a radial plane Q3 passing through the intersection of the first end cutting edge 51 and the second end cutting edge 52, and a radial plane Q4 passing through the chip groove 3 and the closest point to the radial plane Q1. The vertical distance L3 between Q3 and Q4 is 0.005-0.015D.

[0041] Essentially, L3 determines the path length of the chip into the chip groove 3 after the tool tip cuts. When L3 is too large, there is a long transition area between the first end cutting edge 51 and the chip groove 3, making it easy for chips to accumulate near the tool tip, leading to secondary cutting, built-up edge, and localized heat concentration; at the same time, cutting fluid also has difficulty entering the tool tip area. If L3 is too small, the chip groove 3 is too close to the tool tip, which will weaken the thickness of the support material behind the tool tip and reduce the structural strength of the tool tip area. Therefore, by limiting L3 to the range of 0.005D-0.015D, the chip groove 3 can quickly receive the chips from the tool tip without significantly weakening the support strength of the tool tip, thus balancing chip removal capability and tool tip rigidity.

[0042] In some embodiments, please refer to Figure 1 , Figure 3 and Figure 7 As shown, the first end cutting edge 51 forms a first cutting edge inclination angle γ1 with the radial plane of the milling cutter, and γ1 is 0°-3°; the second end cutting edge 52 forms a second cutting edge inclination angle γ2 with the radial plane of the milling cutter, and γ2 is 7°-12°.

[0043] The first end cutting edge 51, located in the tip region, has a small first cutting edge inclination angle γ1. Since the first end cutting edge 51 directly corresponds to the root-cleaning cutting area of ​​the tool tip 1, the smaller inclination angle allows the end cutting edge to be closer to the radial plane, thereby maintaining high cutting sharpness. During the cutting process, the tool tip can cut into the workpiece material with less cutting resistance, making the cutting action lighter and reducing plastic deformation and frictional heat accumulation caused by compression in the tool tip region.

[0044] The second end cutting edge 52, located in the transition region at the center of the tool, has a larger second cutting edge inclination angle γ2. As the inclination angle gradually increases, the actual contact area between the second end cutting edge 52 and the workpiece surface decreases during radial cutting, thereby reducing cutting resistance and frictional load, making the main cutting process more labor-saving. At the same time, the larger inclination angle will deflect the direction of the cutting force, converting part of the radial cutting force into an axial component, thereby reducing the radial impact load on the tool.

[0045] The core of this composite cutting edge tilt structure lies in forming a synergistic cutting mode of sharp cutting at the tip and stable load reduction in the main body. The first end edge 51 is responsible for achieving high-precision root clearing and high surface quality machining, while the second end edge 52 is responsible for reducing the radial cutting force and vibration tendency in the main cutting area. Due to the reduced radial force, the tool is less prone to tool runout and workpiece chatter due to cutting force fluctuations in long overhang machining, thin-walled part machining, and insufficient rigidity conditions, thus effectively suppressing machining vibration and improving cutting stability.

[0046] Furthermore, the vertical distance L2 essentially determines the effective cutting span of the first end edge 51 in the radial direction. When L2 is within a reasonable range, the first end edge 51 can form a low-angle root-clearing region of appropriate length. Due to the small γ1, this region has high cutting sharpness and strong root-clearing ability, enabling it to cut into the bottom corner of the workpiece with low cutting resistance, achieving better surface quality and theoretical root-clearing effect. At the same time, since L2 forms a gradual region of a certain length, the cutting load at the tool tip will not be concentrated at a single point on the tip 14, but can gradually diffuse along the first end edge 51, thereby reducing local stress concentration at the tool tip.

[0047] As the cutting zone gradually transitions to the second end edge 52, the cutting edge inclination angle also gradually changes from a smaller γ1 to a larger γ2. This process means that the direction of the cutting force and the cutting contact state also change synchronously. Among them, the small cutting edge inclination angle region is mainly responsible for sharp cutting and root clearing, while the large cutting edge inclination angle region gradually reduces the radial contact area between the tool and the workpiece and converts part of the radial force into an axial component force.

[0048] If L2 is too small, it means that the length of the first cutting edge 51 is insufficient and the small cutting edge inclination area is too short. At this time, the cutting load of the tool tip will be highly concentrated near the tip 14, while the larger second cutting edge inclination area will participate in cutting too early, causing the cutting force direction to change rapidly, which can easily lead to obvious abrupt changes in cutting force and local vibration. At the same time, due to the insufficient sharp cutting area, the cutting lightness of the tool tip decreases, and the surface quality of the root clearing area is also prone to deterioration.

[0049] Conversely, if L2 is too large, it means that the proportion of the low-angle cutting edge region is too high. Although this can further improve cutting sharpness, the increased contact area between the low-angle cutting edge region and the workpiece significantly increases the duration of the cutting load in the tool tip region, leading to enhanced friction and heat accumulation in the tool tip region. At the same time, the timing of the high-angle cutting edge region's participation in cutting is delayed, weakening its effect of reducing radial force and suppressing vibration, thus affecting overall machining stability.

[0050] In some embodiments, please refer to Figure 9 As shown, the cutting edge 61 is located at an angle of β degrees between the tangent of the tip 14 and the radial plane of the milling cutter, and the angle β is 70°-90°.

[0051] Because the cutting edge 61 does not extend directly in the radial direction, but forms a certain deflection angle relative to the tangent of the tip 14, the cutting tip will not form a traditional direct vertical impact during cutting, but will instead form a certain lateral cutting tendency. This structure allows the cutting load to gradually spread along the cutting edge 61 after the tip 14 contacts the workpiece, rather than being concentrated in a single point area, thereby reducing the phenomenon of local stress concentration at the tip and improving the chipping resistance of the tip area.

[0052] Meanwhile, due to the spatial deflection of the cutting edge 61, a smoother contact trajectory is formed between the tool tip and the bottom corner of the workpiece. This structure reduces the impact vibration generated when the tool tip suddenly cuts into the corner of the workpiece, thereby improving the surface quality of the machined area.

[0053] If the β angle is too small, the cutting edge 61 will approach a radial straight line structure, making it difficult to achieve progressive cutting and cutting force dispersion effects; if the β angle is too large, it will lead to excessive lateral cutting force at the tool tip, affecting cutting stability. Therefore, limiting the β angle to the range of 70°-90° can balance cutting stability, tool tip strength, and chip removal guidance effects.

[0054] Further, please refer to Figure 1 and Figure 3 As shown, the cutting edge 62 extends in a spiral shape in the circumferential direction of the milling cutter with a spiral angle of 30°-45°. The cutting edge 61 and the cutting edge 62 are connected by a circular arc. The spiral angles of the multiple cutting edges 62 in the circumferential direction of the milling cutter are not equal.

[0055] The function of the helical cutting edge 62 is to allow the cutting teeth to gradually enter the cutting state, rather than cutting into the material all at once. This effectively reduces the cutting impact load per unit time, making the cutting process more continuous and stable, thereby reducing vibration and noise.

[0056] Meanwhile, the spiral structure also enables the chips to form an axial curling motion during the cutting process, guiding the chips to be discharged along the direction of the chip groove 3, thereby reducing chip entanglement and clogging, and improving chip discharge stability.

[0057] The use of a circular arc transition between the cutting edge 61 and the cutting edge 62 creates a continuous transition surface between the tool tip area and the main helical cutting edge. This avoids the stress abrupt changes that occur in traditional sharp, broken-line connection structures, allowing the cutting load to smoothly transition from the tool tip area to the main cutting edge 62 area, thus improving the tool tip fatigue life.

[0058] Furthermore, the helix angles of the multiple cutting edges 62 are not equal, forming a variable helix structure. Because the cutting entry timing of different cutting teeth is different, the periodic cutting frequency can be broken up, the probability of resonance is reduced, machining vibration marks and squealing phenomena are reduced, and the stability of high-speed cutting is improved.

[0059] Furthermore, the difference in helix angle of each cutting edge 62 in the circumferential direction of the milling cutter φ satisfies 0.5°≤| φ|≤5°.

[0060] When there is a certain difference in helix angle between adjacent cutting edges 62, the timing of different cutting teeth entering the cutting process will be misaligned, thereby disrupting the fixed periodic excitation frequency formed by the traditional helical structure. This effectively disperses the cutting vibration spectrum and reduces the risk of resonance and howling.

[0061] like If φ is too small, the difference in cutting timing between different cutting edges 62 will be insufficient, making it difficult to form an effective vibration damping effect, and the vibration suppression effect of the variable helical structure will be significantly reduced. However, if... If φ is too large, the difference in cutting load between different cutting teeth will increase significantly. Some cutting teeth will bear a greater load due to prolonged cutting contact time, leading to accelerated local wear and disrupting the overall cutting balance of the tool. Therefore, by... The φ is limited to the range of 0.5°-5° so that each cutting tooth can generate sufficient vibration disturbance while maintaining the overall cutting load balance, thus taking into account both machining stability and tool life.

[0062] In some embodiments, please refer to Figure 1 , Figure 2 and Figure 4As shown, the radial plane of the end mill intersects with the tip clearance face 13 to form a helical section. The radius of rotation of this helical section gradually decreases in the direction from the chip flute 3 to the cutter body clearance face 23. This structure means that the tip clearance face 13 is not a clearance face with a constant radius, but rather gradually contracts inwards in the direction away from the chip flute 3. Essentially, this creates a solid material distribution that is thicker at the front and thinner at the back in the tip region.

[0063] Near the cutting edge, due to the larger radius of rotation, more solid material is retained behind the tool tip, which enhances the basic support capacity of the tool tip 1 and improves its impact resistance and chipping resistance. As the tool tip clearance face 13 gradually contracts inward, a larger clearance space is formed between the tool body clearance face 23 and the workpiece, thereby reducing the friction area of ​​the tool body clearance face 23 and reducing the accumulation of cutting heat and wear of the tool body clearance face 23.

[0064] Furthermore, in the direction from the chip groove 3 to the back angle face 23 of the cutter body, the back angle face 13 of the cutter tip is composed of multiple sub-helical surfaces 131 arranged in sequence. The radial plane of the milling cutter intersects with the multiple sub-helical surfaces 131 to form multiple sub-helical lines. A single sub-helical line extends in a straight line, and two adjacent sub-helical lines have an abrupt transition.

[0065] The essence of this structure is to form multiple different support areas in the rake face 13 region of the tool tip. The sub-helical surface 131 near the cutting edge 62 can retain a larger material thickness, thereby improving the local rigidity of the tool tip region. The sub-helical surface 131 away from the cutting edge 62 transitions relatively to the arc surface, and the abrupt transition can quickly form a clearance space to reduce frictional resistance.

[0066] In some embodiments, please refer to Figure 8 As shown, in traditional equal-pitch milling cutters, each tooth enters the cutting area at a fixed cycle, thus forming a stable periodic excitation frequency, which can easily cause resonance, vibration marks, and howling.

[0067] Therefore, a tooth pitch angle θ is formed between two adjacent second end cutting edges 52 of the milling cutter of the present invention. i (i=1, 2, ..., N, where N is the number of teeth on the milling cutter), multiple tooth pitch angles θ in the circumferential direction of the milling cutter. i They are not equal.

[0068] Variable pitch structures alter the time interval between each cutting tooth's entry into the cutting process, discretizing the cutting excitation frequency and thus weakening the conditions for stable resonance in the cutting system. Particularly during corner clearing, the relatively low local rigidity of the tool tip region makes it susceptible to chipping if periodic vibrations occur. Variable pitch structures reduce the cumulative vibration effect in the tool tip region, improving cutting stability. Simultaneously, the cutting load is further discretized and distributed among the teeth, reducing local instantaneous load peaks and thus improving surface finish and tool life.

[0069] Furthermore, the tooth pitch angle θ i Satisfy: θ min ≥0.8 (360° / N), θ max ≤1.2 (360° / N), and all θ i The sum is 360°, θ min For θ i The minimum value of θ max For θ i The maximum value of θ. min With θ max The limitation means that the range of tooth pitch variation is controlled near the theoretical average tooth pitch.

[0070] Specifically, if the tooth pitch angle is too small, the distance between adjacent teeth will be too close, leading to concentrated cutting loads in the local cutting area and easy chip accumulation. If the tooth pitch angle is too large, the individual tooth will participate in cutting for too long, easily leading to accelerated local wear and potentially disrupting the tool's dynamic balance. Simultaneously, all θ... i The sum of these angles is 360°, which ensures a balanced circumferential mass distribution of the tool and avoids eccentric vibration during high-speed rotation.

[0071] Therefore, by constraining the range of variable tooth pitch, the tool can maintain good cutting stability, rotational balance, and uniform tooth load while retaining its vibration damping capability.

[0072] It should be noted that this application is not limited to the above-described embodiments. The above embodiments are merely examples, and any embodiments with the same structure and effect as the technical concept within the scope of this application are included in the technical scope of this application. Furthermore, various modifications that can be conceived by those skilled in the art to the embodiments, and other ways of constructing by combining some of the constituent elements of the embodiments, without departing from the spirit of this application, are also included in the scope of this application.

Claims

1. A circular arc-shaped end mill for cleaning the root, characterized in that, include: The tip (1) includes a front angle face (11), a tip face (12), a back angle face (13), and a tip (14). The rotation radius D of the tip (14) is the maximum rotation radius of the tip (1). The tip (14) is the earliest contact point between the milling cutter and the workpiece during milling. The milling cutter forms a radial plane Q1 passing through the earliest contact point. The tangent at any point of the tip face (12) forms an angle of α degrees with the radial plane of the milling cutter, and the angle α is 3°-18°. The cutter body (2) includes a front angle face (21), an end face (22), and a rear angle face (23). The front angle face (11) and the rear angle face (13) of the tip meet to form a cutting edge (61). The milling cutter has radial planes Q1 and Q2 passing through the two endpoints of the cutting edge (61). The vertical distance L1 between Q1 and Q2 is 0.01D-0.05D. The front angle face (11) of the tip and the front angle face (21) of the cutter body form a cutting face (4). The tip face (12) of the cutter and the cutting face (4) meet to form a first end edge (51). The end face (22) of the cutter body and the cutting face (4) meet to form a second end edge (52). The two endpoints of the first end edge (51) respectively form rotating circular tangents S1 and S2. The vertical distance L2 between S1 and S2 is 0.02D-0.3D. The chip groove (3) is connected to the back face (13) of the cutting tip and the cutting face (4). The milling cutter forms a radial plane Q3 passing through the intersection of the first end cutting edge (51) and the second end cutting edge (52), and a radial plane Q4 passing through the chip groove (3) and the closest point to the radial plane Q1. The vertical distance L3 between Q3 and Q4 is 0.005-0.015D.

2. The arc-shaped cutting edge end mill according to claim 1, characterized in that, The first end cutting edge (51) forms a first cutting edge inclination angle γ1 with the radial plane of the milling cutter, and γ1 is 0°-3°; the second end cutting edge (52) forms a second cutting edge inclination angle γ2 with the radial plane of the milling cutter, and γ2 is 7°-12°.

3. The arc-shaped cutting edge end mill according to claim 1, characterized in that, The cutting edge (61) is located at an angle of β degrees between the tangent of the tip (14) and the radial plane of the milling cutter, and the β angle is 70°-90°.

4. The arc-shaped cutting edge end mill according to claim 3, characterized in that, The cutting edge (62) is formed by the intersection of the back face (13) of the cutting tip and the chip groove (3). The cutting edge (62) extends in a spiral shape in the circumferential direction of the milling cutter with a spiral angle of 30°-45°. The cutting edge (61) and the cutting edge (62) are connected by a circular arc. The spiral angles of the multiple cutting edges (62) in the circumferential direction of the milling cutter are not equal.

5. A circular arc-shaped end mill for cleaning the root, as described in claim 4, characterized in that, The difference in helix angle of each cutting edge (62) in the circumferential direction of the milling cutter φ satisfies 0.5°≤| φ|≤5°.

6. The arc-shaped cutting edge end mill according to claim 1, characterized in that, The radial plane of the milling cutter intersects with the back angle face (13) of the cutter tip to form a helical section. In the direction from the chip groove (3) to the back angle face (23) of the cutter body, the rotation radius of the helical section gradually decreases.

7. A circular arc-shaped end mill for cleaning the root, as described in claim 6, is characterized in that, In the direction from the chip groove (3) to the back face (23) of the cutter body, the back face (13) of the cutter tip is composed of multiple sub-helical surfaces (131) arranged in sequence. The radial plane of the milling cutter intersects with the multiple sub-helical surfaces (131) to form multiple sub-helical lines. A single sub-helical line extends in a straight line, and two adjacent sub-helical lines have an abrupt transition.

8. A circular arc-shaped end mill for cleaning the root, as described in claim 1, characterized in that, The tooth pitch angle θ is formed between two adjacent second end edges (52). i (i=1, 2, ..., N, where N is the number of teeth on the milling cutter), multiple tooth pitch angles θ in the circumferential direction of the milling cutter. i They are not equal.

9. A circular arc-shaped end mill for cleaning the root, as described in claim 8, characterized in that, Tooth pitch angle θ i Satisfy: θ min ≥0.8 (360° / N), θ max ≤1.2 (360° / N), and all θ i The sum is 360°.

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