Ball-end milling cutter

Abstract

The utility model relates to a ball-end milling cutter which comprises a ball-end cutter body arranged in the axis direction, the ball-end cutter body comprises at least one ball-end cutting unit, and each ball-end cutting unit comprises a center blade and two adjacent ball-end cutting parts arranged in the axis direction. The ball head cutting part comprises a ball head front tool face, a ball head rear tool face and a ball head cutting edge, the ball head front tool face and the ball head rear tool face intersect, and the ball head cutting edge is arranged at the intersection position of the ball head front tool face and the ball head rear tool face. The two ball head rear tool faces of every two adjacent ball head cutting parts intersect, the center edge is arranged at the intersection position, and the center edge is a linear edge and located in the center of the spherical bottom of each ball head cutting part. The ball-end milling cutter can improve the surface quality of a machined workpiece and avoid abrasion and breakage of the center part of the cutting edge.

Description

Technical Field

[0001] The present application relates to a cutting tool, in particular to a ball end milling cutter. Background Art

[0002] In the prior art, when the center of the bottom of the ball-end milling cutter is performing plane cutting, the vertex of the arc of the tool cutting edge first contacts the workpiece surface, and then extends to the center of the tool and the peripheral edge. Since the linear velocity of the vertex position is 0, and the vertex position is at the lowest position during the processing, the vertex position that contacts the workpiece first is more susceptible to wear, resulting in a larger surface roughness of the workpiece after processing this part, and the surface quality of the workpiece is poor. At the same time, the chips generated by the first processing of the vertex are easily blocked at the center of the tool, causing secondary cutting at the center, and the linear velocity at the center is relatively low, so it is very easy to cause the center of the tool to collapse. Utility Model Content

[0003] In order to solve at least one of the above technical problems, the present application provides a ball end milling cutter.

[0004] The specific technical solutions adopted in this application are as follows:

[0005] The ball end milling cutter of the present application comprises a ball end cutter body arranged along the axial direction, the ball end cutter body comprises at least one ball end cutting unit, the ball end cutting unit comprises a center edge and two adjacent ball end cutting parts respectively arranged along the axial direction, the ball end cutting parts comprise a ball end rake face, a ball end flank face and a ball end cutting edge, the ball end rake face intersects with the ball end flank face and the ball end cutting edge is arranged at the intersection; the two ball end flank faces of the two adjacently arranged ball end cutting parts intersect and the center edge is arranged at the intersection, the center edge is a straight edge or close to a straight edge, and the center edge is located at the center position of the spherical bottom of the ball end cutting part.

[0006] Through the above technical solution, the present application designs a center blade at the center of the spherical bottom of the ball head cutting part (i.e., the center of the bottom blade of the tool) on the premise of ensuring that the R value contour of the ball head part is qualified, so that the lowest cutting point of the overall tool during plane processing is moved outward, and the cutting speed of the ball head center processing part is improved. At the same time, due to the existence of the center blade, the processing residual height can be effectively reduced, and the surface quality of the workpiece being processed can be improved. That is, the ball head milling cutter of the present application can improve the surface quality of the workpiece processed by the ball head milling cutter and enhance the strength of the center part of the tool.

[0007] As one embodiment, the ball head back cutting surface includes a first back cutting surface, a second back cutting surface and a third back cutting surface which intersect in sequence, the ball head front cutting surface intersects with the first back cutting surface and the ball head cutting edge is arranged at the intersection of the ball head front cutting surface and the first back cutting surface, and the two first back cutting surfaces in two adjacent ball head cutting parts intersect and the center edge is arranged at the intersection.

[0008] Through the above technical solution, as a specific structural example, the ball head flank surface can be composed of a first flank surface, a second flank surface and a third flank surface, the first flank surface intersects with the second flank surface, the second flank surface intersects with the third flank surface, the ball head rake surface intersects with the first flank surface and forms a ball head cutting edge at the intersection, and in two adjacent ball head cutting parts, the two first flank surfaces intersect and form a center edge at the intersection. The structural design of this embodiment is simple, and the position of the center edge can be adjusted more conveniently according to actual needs, so that it is located at the center of the spherical bottom of the ball head cutting part.

[0009] As an embodiment, the ball end cutter body comprises at least two ball end cutting units, and the center edges of the at least two ball end cutting units are respectively located at the center position of the spherical bottom of the respective ball end cutting parts.

[0010] Through the above technical solution, as a specific structural example, each ball head cutting unit is designed to consist of two ball head cutting parts, that is, the ball head cutting parts are all even numbers. In principle, the number of ball head cutting units can be multiple, and multiple center blades are correspondingly provided. The multiple center blades can be located at the center position of the spherical bottom of the corresponding ball head cutting part.

[0011] As an embodiment, the ball end mill meets the following condition: 0°<ψ≤20°, wherein ψ is the angle between a vertical line perpendicular to the axial direction and the center blade.

[0012] Through the above technical scheme, as a structural example, the angle of ψ is designed to be greater than 0 and less than or equal to 20°. For example, any value of 1°, 2°, 3°, 4°, 5°, 6°, 7°, 8°, 9°, 10°, 11°, 12°, 13°, 14°, 15°, 16°, 17°, 18°, 19°, 20°, etc. can be selected according to actual needs. The smaller the angle of ψ, the longer the length of the bottom center blade, and the better the surface quality of the plane processing.

[0013] As one embodiment, the ball end milling cutter satisfies the following condition: X=(1% to 2.5% multiple range)*Dc, wherein X is the minimum thickness between the respective ball end cutting edges of two adjacently arranged ball end cutting portions, and Dc is the diameter of the ball end cutter body.

[0014] Through the above technical scheme, as a structural example, the minimum thickness between two adjacent self-ball head cutting edges is determined according to 1%-2.5% (i.e., a multiple range of 1% to 2.5%) of the diameter of the ball end cutter body. For example, any value in multiples such as 1%, 1.1%, 1.2%, 1.3%, 1.4%, 1.5%, 1.6%, 1.7%, 1.8%, 1.9%, 2%, 2.1%, 2.2%, 2.3%, 2.4%, 2.5% can be selected according to actual needs. The larger the value, the higher the center strength of the bottom of the ball head, which is more suitable for rough machining conditions. However, during the machining process, the contact area between the back face of the tool at this position and the machined surface is also larger.

[0015] As one embodiment, the ball end milling cutter satisfies the following conditions: sinψ / X≤φDe≤20%Dc, wherein ψ is the angle between a vertical line perpendicular to the axial direction and the center edge, X is the minimum thickness between the respective ball end cutting edges in two adjacent ball end cutting portions, φDe is the rotation diameter of the center edge, and Dc is the diameter of the ball end cutter body.

[0016] Through the above technical scheme, as a structural example, the size of the rotation diameter of the center blade is determined according to the above conditions. In principle, any value within the above conditions can be selected. When the workpiece first contacts the center blade at the diameter De of the center blade, the center blade has a certain linear velocity at this time, which is 0 compared to the linear velocity of the center part of the traditional ball head tool. The size of the rotation diameter of the center blade is adjusted according to the above conditions, which can further achieve effective cutting instead of pure friction and extrusion of the workpiece, thereby avoiding rapid wear and chipping of the cutting edge.

[0017] As an embodiment, the ball end milling cutter satisfies the following condition: 0.1%Dc≤h≤1%Dc, wherein Dc is the diameter of the ball end cutter body, and h is the distance between the center edge and the center vertex of the spherical surface of the ball end cutting portion along the axial direction.

[0018] Through the above technical scheme, as a structural example, the distance between the center edge and the center vertex formed by the spherical surface of the ball-end cutting part along the axial direction is specifically controlled at 0.1%-1% of the diameter of the ball-end cutter body. For example, any value among 0.1%, 0.2%, 0.3%, 0.4%, 0.5%, 0.6%, 0.7%, 0.8%, 0.9%, and 1% can be selected according to demand. The cutting point can be further adjusted to be within a reasonable range to ensure that the cutting point is transferred to the diameter De formed by the center edge. It has a certain finishing effect when machining the plane, can effectively reduce the residual height Rz value of the workpiece, and improve the surface quality of the machined workpiece.

[0019] As one embodiment, the ball end mill satisfies at least one of the following conditions: -10°≤γ≤15°, 5°≤β≤20°, 1.2β≤δ≤3β; wherein γ is the normal rake angle of the ball end cutting edge, β is the first clearance angle corresponding to the first clearance face, and δ is the second clearance angle corresponding to the second clearance face.

[0020] Through the above technical solution, as a structural example, the normal front angle γ of the ball head cutting edge, that is, the angle between the ball head cutting edge and the base surface, γ can be selected according to the needs of -10°, -9°, -8°, -7°, -6°, -5°, -4°, -3°, -2°, -1°, 0°, 1°, 2°, 3°, 4°, 5°, 6°, 7°, 8°, 9°, 10°, 11°, 12°, 13°, 14°, 15° any value; the first back angle β is the angle between the first back tool face and the cutting plane, β can be selected according to the needs of 5°, 6°, 7°, 8°, 9°, 10°, 11°, 12° any value among 1.1, 1.5, 2.6, 2.7, 2.8, 2.9, 3, etc. of β; through the design of γ, β, and δ, suitable tool structure parameters for cutting different processed materials such as P, K, H, N, M, and S can be achieved.

[0021] As an embodiment, the surface of the ball head cutting edge is provided with at least one of the following coatings: AlTiN coating, AlCrN coating, AlTiN and SiN composite coating, AlCrN and SiN composite coating, TiB 2 Coating, TiSiN coating, TiCN coating.

[0022] Through the above technical solution, as a structural example, one or more layers of coating can be set on the surface of the ball head cutting edge according to actual needs to achieve technical effects such as protecting the ball head cutting edge and improving the service life. The coating can be selected from AlTiN coating, AlCrN coating, AlTiN and SiN composite coating, AlCrN and SiN composite coating, TiB 2 Coating, TiSiN coating, TiCN coating, etc., any one of the above coatings can be selected, or at least two or more of them can be selected to form a composite coating structure. The coating stacking sequence in the composite coating structure can be adjusted according to actual needs. At the same time, in terms of process, for example, blunting treatment can be adopted, and the specific required coating can be determined according to processing conditions and processing materials.

[0023] As one embodiment, the ball end milling cutter also includes a shank and a contracted neck, the ball end cutter body is coaxially arranged with the shank, the ball end cutter body also includes a circumferential front cutting edge, a circumferential back cutting edge and a circumferential cutting edge, the circumferential front cutting edge and the circumferential back cutting edge are provided at the intersection; the shank and the circumferential cutting edge are connected by the contracted neck.

[0024] Through the above technical solution, as a structural example, a shrink neck can be added between the shank and the circumferential cutting edge according to the processing conditions. In addition, the shank can be selected to use a straight shank, a tapered shank, a side-lock shank, a spiral groove shank, a threaded interface, etc. according to the needs.

[0025] In summary, this application has the following beneficial effects:

[0026] The ball-end milling cutter of the present application is designed with a straight edge or a center edge close to a straight edge at the center position of the spherical bottom of the ball-end cutting portion. The center edge becomes the lowest cutting edge during machining, which changes the position of the center of the bottom of the ball end that actually participates in cutting. Compared with ordinary ball-end milling cutters, the residual height of the machined surface can be reduced and the surface quality of the machined workpiece can be improved. At the same time, the design of the above-mentioned center edge makes the first contact point with the workpiece at the diameter of the center edge, preventing stress from concentrating on the apex of the center arc (i.e., the center apex formed by the spherical surface of the ball-end cutting portion along the axial direction), thereby avoiding wear and chipping of the cutting edge. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] Figure 1 is a schematic diagram of the main body of the ball end milling cutter of the embodiment of the present application;

[0028] Figure 2 1 is a schematic diagram of a ball end cutter body in a ball end milling cutter according to an embodiment of the present application;

[0029] Figure 3 It corresponds to Figure 1 An enlarged view of the center of the bottom blade of the ball head;

[0030] Figure 4 It corresponds to Figure 2 An enlarged view of the center of the ball head bottom edge;

[0031] Figure 5 It is a schematic diagram of the three-dimensional structure of the ball end milling cutter according to an embodiment of the present application.

[0032] Description of labels:

[0033] 10. Ball-end cutter body; 1. Center edge; 2. Ball-end rake face; 3. Ball-end cutting edge; 4. First clearance face; 5. Second clearance face; 6. Third clearance face;

[0034] 7. Circumferential rake face; 8. Circumferential flank face; 9. Circumferential cutting edge;

[0035] 20. Handle; 30. Contracted neck. DETAILED DESCRIPTION

[0036] The present application is further described in detail below with reference to the accompanying drawings and embodiments.

[0037] Example 1

[0038] The ball end milling cutter according to one embodiment of the present invention can be seen in Figure 1-5 , wherein the same reference numerals denote corresponding parts throughout all the figures. It should be understood that the ball end milling cutter according to the present application can be generally used for milling of various types of workpiece surfaces in the prior art.

[0039] like Figure 1 As shown, the ball end milling cutter of this embodiment comprises: a ball end mill body 10, a shank 20 and a contracted neck 30. The ball end mill body 10 and the shank 20 are coaxially arranged and are both arranged along the axis L1.

[0040] See also Figure 1 The ball end tool body 10 includes a circumferential rake face 7, a circumferential flank face 8, a circumferential cutting edge 9 and at least one ball end cutting unit (the ball end cutting unit shown in this embodiment is one), the circumferential rake face 7 intersects with the circumferential flank face 8 and forms a circumferential cutting edge 9 at the intersection; the shank 20 and the circumferential cutting edge 9 are connected by a contraction neck 30.

[0041] See also Figure 1-3 The ball-end cutting unit includes a center blade 1 and two adjacent ball-end cutting parts respectively arranged along the axis L1. Figure 1 as well as Figure 5 Each ball-end cutting portion includes a ball-end rake face 2, a ball-end cutting edge 3, a first clearance face 4, a second clearance face 5 and a third clearance face 6. The ball-end rake face 2 intersects with the first clearance face 4 and a ball-end cutting edge 3 is formed at the intersection. The ball-end rake face 2 is transitionally connected to the circumferential rake face 7, the ball-end cutting edge 3 is transitionally connected to the circumferential cutting edge 9, and the first clearance face 4 is transitionally connected to the circumferential clearance face 8. Figure 1 The ball head cutting part is formed into a spherical shape as a whole, and the diameter of the ball head cutter body is defined by the spherical ball head cutting part, which is Figure 1 Dc shown in .

[0042] See also Figure 2-5 The two first flank surfaces 4 in the two adjacent ball-end cutting parts intersect and form a center edge 1 at the intersection. Figure 3-5 The center edge 1 is a straight edge, which is a straight edge or an edge close to a straight line. The center edge 1 is located at the center of the spherical bottom of the ball head cutting part. Figure 3The center blade 1 of this embodiment is symmetrically arranged along the axis L1, the ball head cutting portion is formed into a spherical shape as a whole, and the center position of the spherical bottom of the ball head cutting portion is not in an arc shape ( Figure 3 The arc dotted line shown in the figure represents the surface trajectory of the center position of the spherical bottom of the ball head cutting part if it is a closed arc shape), but is a straight line or close to a straight line, and the center edge 1 is located at the center position of the spherical bottom formed by the ball head cutting part. The diameter of the center edge 1 is Figure 3 The distance between the center edge 1 and the center vertex of the spherical surface of the ball-end cutting part along the axial direction is the distance between the center edge 1 and the center vertex of the spherical surface of the ball-end cutting part along the axial direction. Figure 3 The distance between the central vertices of the arc dashed line shown in Figure 1 h shown in . Figure 3 R shown in is the ball head radius of the ball head cutting unit.

[0043] See also Figure 2 and Figure 4 , the vertical line L2 is perpendicular to the axis L1, Figure 4 The indicated ψ is the angle between the center edge 1 and the vertical line L2. Figure 4 The X shown represents the thickness between the respective ball-end cutting edges 3 in two adjacently arranged ball-end cutting parts. Figure 4 φDe shown is the rotation diameter of the center cutting edge 1 .

[0044] Specifically, the specific structural parameter design of the ball end mill in this embodiment meets the following conditions: 0°<ψ≤20°; X=(1% to 2.5% multiple range)*Dc; sinψ / X≤φDe≤20%Dc; 0.1%Dc≤h≤1%Dc.

[0045] Specifically, the angle between the ball-end cutting edge and the base surface can be -10° to 15° (including the endpoint values), the angle between the first back cutting edge 4 and the cutting plane can be 5° to 20° (including the endpoint values), and the angle between the second back cutting edge 5 and the cutting plane can be 1.2-3 times the angle between the first back cutting edge 4 and the cutting plane (including the endpoint values).

[0046] Based on the above structural description, the ball end milling cutter of this embodiment is designed with a straight edge or a center edge 1 close to a straight edge at the center position of the spherical bottom of the ball end cutting portion. Due to the existence of the center edge 1, the center edge 1 becomes the lowest cutting edge during processing, which changes the position of the center of the bottom of the ball end that actually participates in cutting. Compared with ordinary ball end milling cutters, the residual height of the processed surface can be reduced and the surface quality of the processed workpiece can be improved. At the same time, the design of the above center edge 1 makes the first point of contact with the workpiece at the diameter of the center edge 1. At this time, the center edge 1 has a certain linear speed, which is 0 compared to the linear speed of the center part of the traditional ball end tool, which can prevent stress concentration. Figure 3The central vertex of the arc dotted line shown in the figure can achieve effective cutting instead of pure friction and squeezing of the workpiece, thereby avoiding rapid wear and chipping of the ball end milling cutter.

[0047] This specific embodiment is merely an explanation of the present application and is not a limitation of the present application. After reading this specification, those skilled in the art may make modifications to the present embodiment without any creative contribution as needed, but such modifications are protected by the patent law as long as they are within the scope of the claims of the present application.

Claims

1. A ball end milling cutter, comprising a ball end mill body arranged along an axial direction, characterized in that: The ball end tool body includes at least one ball end cutting unit, the ball end cutting unit includes a center edge and two adjacent ball end cutting parts respectively arranged along the axial direction, the ball end cutting part includes a ball end rake face, a ball end back face and a ball end cutting edge, the ball end rake face intersects with the ball end back face and the ball end cutting edge is provided at the intersection; the two ball end back faces of the two adjacently arranged ball end cutting parts intersect and the center edge is provided at the intersection, the center edge is a straight edge, and the center edge is located at the center position of the spherical bottom of the ball end cutting part.

2. The ball end milling cutter according to claim 1, characterized in that: The ball-end back cutting surface includes a first back cutting surface, a second back cutting surface and a third back cutting surface which intersect in sequence, the ball-end front cutting surface intersects with the first back cutting surface and the ball-end cutting edge is arranged at the intersection of the ball-end front cutting surface and the first back cutting surface, and the two first back cutting surfaces in the two adjacent ball-end cutting parts intersect and the center edge is arranged at the intersection.

3. The ball end mill according to claim 1, characterized in that: The ball end cutter body comprises at least two ball end cutting units, and the center edges of the at least two ball end cutting units are respectively located at the center of the spherical bottom of the respective ball end cutting parts.

4. The ball end mill according to any one of claims 1 to 3, characterized in that: The following conditions are met: 0°<ψ≤20°, wherein ψ is the angle between a vertical line perpendicular to the axial direction and the center edge.

5. The ball end mill according to any one of claims 1 to 3, characterized in that: The following conditions are met: X=(1% to 2.5% multiple range)*Dc, wherein X is the minimum thickness between the respective ball head cutting edges of two adjacently arranged ball head cutting parts, and Dc is the diameter of the ball head cutter body.

6. The ball end mill according to any one of claims 1 to 3, characterized in that: The following conditions are met: sinψ / X≤φDe≤20%Dc, wherein ψ is the angle between a vertical line perpendicular to the axial direction and the center edge, X is the minimum thickness between the respective ball head cutting edges in two adjacent ball head cutting parts, φDe is the rotation diameter of the center edge, and Dc is the diameter of the ball head cutter body.

7. The ball end mill according to any one of claims 1 to 3, characterized in that: The following conditions are met: 0.1%Dc≤h≤1%Dc, wherein Dc is the diameter of the ball end cutter body, and h is the distance between the center edge and the center vertex of the spherical surface of the ball end cutting portion along the axial direction.

8. The ball end mill according to claim 2, characterized in that: At least one of the following conditions is met: -10°≤γ≤15°, 5°≤β≤20°, 1.2β≤δ≤3β; wherein γ is the normal rake angle of the ball-end cutting edge, β is the first clearance angle corresponding to the first clearance surface, and δ is the second clearance angle corresponding to the second clearance surface.

9. The ball end mill according to claim 1, characterized in that: The surface of the ball head cutting edge is provided with at least one of the following coatings: AlTiN coating, AlCrN coating, AlTiN and SiN composite coating, AlCrN and SiN composite coating, TiB2 coating, TiSiN coating, TiCN coating.

10. The ball end mill according to claim 1, characterized in that: It also includes a shank and a contraction neck. The ball-end tool body is coaxially arranged with the shank. The ball-end tool body also includes a circumferential rake face, a circumferential flank face and a circumferential cutting edge. The circumferential cutting edge is provided at the intersection of the circumferential rake face and the circumferential flank face. The shank and the circumferential cutting edge are connected by the contraction neck.

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