A cutting insert usable for high speed milling and a cutting tool incorporating the high speed milling cutting insert

Abstract

The application discloses a blade and cutter which can be used for high-speed milling, and comprises a main body, a center hole, a bottom surface, a top surface and edge surfaces arranged between the bottom surface and the top surface; wherein two of the edge surfaces are configured as long edge surfaces, and the position where the long edge surfaces are connected with the top surface forms a long edge; the other two of the edge surfaces are configured as short edge surfaces, and the position where the short edge surfaces are connected with the top surface forms a short edge; the included angle between each edge surface and the bottom surface is obtuse; each long edge has an arc-shaped edge section, and each arc-shaped edge section protrudes outward along a direction perpendicular to the long edge and passing through the center line of the long edge; the long edge surface and the position corresponding to the arc-shaped edge section form a curved surface which is outwardly convex and used for supporting the arc-shaped edge section; the application provides a milling blade and cutter, and effectively solves the problems of low surface quality, obvious tool joint marks, rough surface and insufficient precision of the existing blade type milling cutter.

Description

Technical Field

[0001] This invention relates to the field of cutting tools, and more specifically to a cutting insert that can be used for high-speed milling and a cutting tool equipped with a high-speed milling insert. Background Technology

[0002] Currently, milling tools are generally divided into shank-type milling cutters and insert-type milling cutters. Insert-type milling cutters are widely used due to their advantages such as low cost and long service life. Specifically, insert-type milling cutters consist of a cutter body and a cutter clamping part (i.e., a shank), and are used to process parts such as planes, steps, grooves, shaped surfaces, and cut off workpieces on milling machines.

[0003] With the continuous development and progress of automated machining, the requirements for interchangeable insert end mills are also constantly increasing. Especially in high-speed milling, how to process parts efficiently and with high quality has become an important direction for tool design. Although existing interchangeable insert end mills can meet the requirements of efficient machining at high speeds, the surface quality of the machined products is unsatisfactory. The machined product surface has severe tool marks, that is, an arc-shaped groove is formed between two feed depths. In other words, a wavy mark (i.e., tool marks) is formed along the feed direction. The reason for such obvious wavy tool marks is the tool structure design and the axial and radial angles after assembly to the tool holder. When the insert is installed in the tool body and rotates at high speed, the envelope formed by the cutting edge becomes a state of concave in the middle and convex at both ends. This forms a plane with a convex middle and concave at both ends on the feed surface. The two ends are the positions where tool marks are generated, ultimately forming wavy tool marks. This directly affects the dimensional accuracy and quality of the entire machined surface.

[0004] Therefore, how to improve the above-mentioned problems is also the technical difficulty that the applicant wants to solve. Summary of the Invention

[0005] The purpose of this invention is to overcome the above-mentioned defects or problems in the prior art and to provide a cutting insert and a tool equipped with a high-speed milling insert that can be used for high-speed milling. The insert has a simple structure, is easy to manufacture, is easy to implement and has low cost, and effectively solves the problems of low surface quality, obvious tool marks, rough surface and insufficient precision in the machining of existing insert milling cutters.

[0006] To achieve the above objectives, the present invention adopts the following technical solution:

[0007] An insert for high-speed milling includes a body, a central hole formed in the body, a bottom surface, a top surface, and an edge surface disposed between the bottom surface and the top surface; wherein two of the edge surfaces are configured as long cutting surfaces, and the positions where the long cutting surfaces are connected to the top surface form long edge cutting edges; and the other two edge surfaces are configured as short cutting surfaces, and the positions where the short cutting surfaces are connected to the top surface form short edge cutting edges.

[0008] The angle between each of the edge surfaces and the bottom surface is set to an obtuse angle;

[0009] Each of the long edge blades has an arc-shaped blade segment, and each arc-shaped blade segment protrudes outward along a direction perpendicular to the long edge blade and through its midline;

[0010] The long blade surface forms an outwardly convex curved surface corresponding to the position of the arc-shaped blade segment, which is used to support the arc-shaped blade segment; on the transverse cross section of the main body, the curved surface gradually transitions from the arc-shaped blade segment to the bottom surface in an arc shape.

[0011] Preferably, the calculation formula for the forming of the long edge blade with the arc-shaped blade segment is:

[0012] F(S)=π*S*cosβ*cosα / 180*cos(90°-α)

[0013] Wherein, S is the length of the long edge cutting edge; α is the axial rake angle of the main body mounted on the tool holder; and β is the radial rake angle of the main body mounted on the tool holder.

[0014] Preferably, the curvature of the curved surface is the same as the calculation formula for the long edge forming.

[0015] Preferably, each of the short edge blades includes a straight edge portion, a first inclined edge portion, and an arc-shaped edge portion; the straight edge portion is connected to the two long edge blades through the first inclined edge portion and the arc-shaped edge portion, and the included angle between the straight edge portion and the first inclined edge portion is 120° to 140°.

[0016] Preferably, the short edge further includes a second inclined blade portion, which is formed between the first inclined blade portion and the straight blade portion, and the included angle between the second inclined blade portion and the straight blade portion is 150° to 170°; wherein, the length of the first inclined blade portion is greater than the length of the second inclined blade portion.

[0017] Preferably, the bottom surface of the main body is further provided with an assembly groove, which is used for positioning and fitting with the mounting part of the tool holder.

[0018] A cutting tool for mounting a high-speed milling insert includes a tool holder, a slot formed in the tool holder for mounting the insert, and the insert itself, wherein the insert passes through the central hole via a locking fastener to detachably fix the insert in the slot, and one of the long cutting edges and the corresponding short cutting edge of the insert are exposed on the outer peripheral surface and end face of the tool holder.

[0019] Preferably, the bottom of the groove gradually slopes outward along the axial direction of the tool holder, and the bottom of the groove protrudes to form a mounting portion that fits with the assembly groove with a clearance.

[0020] Preferably, a concave recess is formed in the middle of the end of the blade mounted on the tool holder; the two slots are arranged symmetrically with respect to the center of the concave recess, and a clearance groove is formed at each slot.

[0021] Preferably, the tool holder also has an internal cooling channel formed inside, and the liquid inlet of the internal cooling channel is opened at the end of the tool holder away from the blade, and the liquid outlet is located in the groove and faces the long edge and / or short edge.

[0022] As can be seen from the above description of the present invention, compared with the prior art, the present invention has the following beneficial effects:

[0023] This invention provides an insert for high-speed milling and a tool for mounting the high-speed milling insert. It features a simple structure, easy manufacturing, and low cost. The invention modifies the long and short cutting edges of the insert, creating an arc-shaped cutting segment on the long edge and a curved surface on the long edge. When the insert is mounted on the tool holder, its axial and radial angles are improved. During high-speed rotation, the envelope formed by the two inserts on the tool holder is compensated to approach a straight line, resulting in a more straight side surface during milling. This leads to straight tool marks produced by each feed step, significantly improving the quality and dimensional accuracy of the machined surface. More importantly, it not only achieves higher surface quality and accuracy but also expands the application scenarios and flexibility. Attached Figure Description

[0024] To more clearly illustrate the technical solutions of the embodiments of the present invention, the drawings used in the following description of the embodiments are briefly introduced. Obviously, the drawings described below are some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0025] Figure 1 This is a three-dimensional schematic diagram of blade machining in the prior art.

[0026] Figure 2 This is a three-dimensional structural diagram of the cutting tool equipped with a high-speed milling insert in this invention.

[0027] Figure 3 This is a partial schematic diagram of the blade mounted on the blade body in this invention.

[0028] Figure 4 This is a three-dimensional structural diagram of the blade in this invention.

[0029] Figure 5 This is a top view of the blade in this invention.

[0030] Figure 6 This is a bottom view of the blade in this invention.

[0031] Figure 7 This is a three-dimensional structural diagram of the blade body in this invention.

[0032] Figure 8 This is a cross-sectional schematic diagram of the blade in the machining state in this invention.

[0033] Figure 9 This is a three-dimensional schematic diagram of the blade in the processing state in this invention. Attached image description:

[0035] A. The protruding middle portion of the cutting surface; B. The concave portions at both ends of the cutting surface; B1. Tool mark; 1. Main body; 11. Center hole; 12. Bottom surface; 120. Assembly groove; 13. Top surface; 131. Inwardly inclined surface; 132. Inclined surface; 2. Edge surface; 21. Long cutting edge surface; 211. Long edge cutting edge; 211A. Curved cutting edge segment; 211B. Curved surface; 22. Short cutting edge surface; 221. Short edge cutting edge; 221A. 221B, First inclined cutting edge; 221C, Arc-shaped cutting edge; 221D, Second inclined cutting edge; 3, Tool holder; 31, Groove; 311, Groove bottom; 312, Mounting part; 313, Side groove wall; 32, Concave countersunk platform; 33, Clearance groove; S, Length of long edge cutting edge; α, Axial front angle of the main body mounted on the tool holder; β, Radial front angle of the main body mounted on the tool holder; 4, Locking fastener; 5, Liquid outlet; H, Included angle; K, Included angle. Detailed Implementation

[0036] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are preferred embodiments of the present invention and should not be considered as excluding other embodiments. All other embodiments obtained by those skilled in the art based on the embodiments of the present invention without creative effort are within the scope of protection of the present invention.

[0037] Unless otherwise expressly defined, the use of terms such as "first," "second," or "third" in the claims, description, and accompanying drawings of this invention is for distinguishing different objects and not for describing a specific order.

[0038] Unless otherwise expressly defined, in the claims, description, and accompanying drawings of this invention, the use of directional terms such as "center," "lateral," "longitudinal," "horizontal," "vertical," "top," "bottom," "inner," "outer," "upper," "lower," "front," "rear," "left," "right," "clockwise," and "counterclockwise" to indicate orientation or positional relationships is based on the orientation and positional relationships shown in the accompanying drawings and is only for the convenience of describing the invention and simplifying the description. It does not indicate or imply that the device or element referred to must have a specific orientation or be constructed and operated in a specific orientation, and therefore should not be construed as limiting the specific scope of protection of this invention.

[0039] Unless otherwise expressly defined, the terms "fixed connection" or "fixed connection" used in the claims, description and drawings of this invention should be interpreted broadly to refer to any connection in which there is no displacement or relative rotation relationship between the two parties, including non-removable fixed connection, detachable fixed connection, integral connection and fixed connection by other means or components.

[0040] In the claims, description and accompanying drawings of this invention, the terms "comprising", "having", and variations thereof are used to mean "including but not limited to".

[0041] See Figure 1 As shown in the figure, during the cutting process of an existing cutting tool, the envelope formed by the cutting edge becomes concave in the middle and convex at both ends. This results in a plane with a convex middle (A) and concave ends (B) on the feed surface. The two ends are where the tool marks (B1) are generated, ultimately forming wavy tool marks (B1). The resulting surface is uneven and not a complete straight or flat surface, which cannot meet the requirements for machining products with high dimensional accuracy. Therefore, this invention aims to improve this aspect.

[0042] like Figure 4 , 5 As shown in Figure 6, the blade in this embodiment includes a main body 1, a central hole 11 formed in the main body 1, a bottom surface 12, a top surface 13, and an edge surface 2 disposed between the bottom surface 12 and the top surface 13; and the included angle between each of the edge surfaces 2 and the bottom surface 12 is set at an obtuse angle, that is, the outer contour area of ​​the top surface 13 of the main body 1 is larger than the outer contour area of ​​the bottom surface 12, and the edge surface 2 is inclined from the top surface 13 to the bottom surface 12;

[0043] Among them, the two edge surfaces 2 are configured as long blade surfaces 21, and the position where the long blade surfaces 21 are connected to the top surface 13 forms a long edge blade 211;

[0044] The other two edge surfaces 2 are configured as short blade surfaces 22, and the short blade surfaces 22 are connected to the top surface 13 to form a short edge blade 221;

[0045] The long edge 211 and the short edge 221 are defined by length. Generally, the blade has two long edge 211 and short edge 221 arranged symmetrically at the center. After being assembled into the tool holder 3, only one adjacent long edge 211 and short edge 221 participate in cutting. After wear, they are replaced with another long edge 211 and short edge 221 for use.

[0046] like Figure 3-5 As shown, each of the long edge blades 211 has an arc-shaped blade segment 211A. Each of the arc-shaped blade segments 211A protrudes outward along a direction perpendicular to the long edge blade 211 and through its centerline, such as a "reverse C-shaped blade edge", that is, it protrudes outward in the middle of the long edge blade 211.

[0047] It should be noted that the long edge 211 with the convex arc-shaped cutting edge segment 211A is designed using the following calculation formula, specifically:

[0048] F(S)=π*S*cosβ*cosα / 180*cos(90°-α)

[0049] in:

[0050] S is the length of the long edge blade 211;

[0051] α is the axial front angle of the main body mounted on the tool holder 3;

[0052] Please refer to Figure 3 The axial rake angle α is the angle between the inwardly inclined surface 131 on the top surface 13 and the axial horizontal plane after the insert is installed in the slot 31 of the tool holder 3 and the position of the short cutting edge 221 that participates in cutting. It should be noted that the bottom 311 of the slot 31 on the tool holder 3 is inclined downward along the axial direction of the tool holder 3 and towards the end of the tool holder 3. Therefore, after the bottom surface 12 of the insert is assembled with the bottom 311 of the slot, the inclination angle of the inwardly inclined surface 131 on the top surface 13 corresponding to the position of the short cutting edge 221 changes, and the angle formed with the axial horizontal plane is used as the axial rake angle α for design.

[0053] β is the radial rake angle of the main body mounted on the tool holder 3, that is, the angle between the top surface 13 and the horizontal plane; it should be noted that the blade at the long edge 211 position generally has an inwardly inclined design, so the radial rake angle β is the angle between the horizontal plane and the inwardly inclined surface 132.

[0054] The long edge 211 with the arc-shaped cutting edge segment 211A is calculated using the above method; from Figure 8As can be seen, the arc-shaped cutting segment 211A in the long edge 211 protrudes outward, and the distance between the outermost point of the protrusion and the two ends of the long edge 211 (i.e. the two ends connected to the short edge 221) is about 2 to 6 μm.

[0055] Furthermore, the long blade surface 21 forms an outwardly bulging curved surface 211B corresponding to the position of the arc-shaped blade segment 211A, which is used to support the arc-shaped blade segment 211A; on the transverse cross section of the main body 1, the curved surface 211B gradually transitions from the arc-shaped blade segment 211A to the bottom surface 12 in an arc shape; the curvature of this curved surface 211B is the same as the calculation formula for the long edge blade forming, and will not be repeated here;

[0056] Normally, the long edge cutting edge 211 is designed as a straight line. When the cutting edge rotates with the tool holder 3 to mill the workpiece, due to the axial and radial angles of the cutting edge, the envelope of the long edge cutting edge 211 during rotational machining is an inwardly concave arc shape, and the workpiece surface correspondingly forms an outwardly convex arc surface A (e.g., ...). Figure 1 As shown), the machined surface exhibits an uneven, wavy tool mark (i.e., tool mark B1) at every step interval. This invention compensates for the envelope of the long edge 211 of the blade by using the outwardly convex arc-shaped cutting segment 211A "reverse C-shaped cutting edge" design, making it approach a straight line (as shown). Figure 9 (As shown) This reduces or eliminates tool marks, significantly reduces the roughness of the machined surface, and greatly improves the machining dimensions and surface accuracy.

[0057] like Figure 4 , 6 As shown, the short edge 221 includes a straight edge portion 221A, a first inclined edge portion 221B, and an arc-shaped edge portion 221C;

[0058] The straight cutting edge 221A is connected to the two long-side cutting edges 211 through the first inclined cutting edge 221B and the arc-shaped cutting edge 221C, and the included angle H between the straight cutting edge 221A and the first inclined cutting edge 221B is 120° to 140°. This shortens the cutting edge involved in end face (plane) cutting, resulting in a smaller contact area, better force control, and less likelihood of tool vibration and chipping during high-feed machining. It also creates a good finishing edge effect, significantly improving surface quality. In addition, it can achieve slope machining and is less prone to machining interference.

[0059] Furthermore, the short-edge cutting edge 221 also includes a second inclined cutting edge 221D, which is formed between the first inclined cutting edge 221B and the straight cutting edge 221A, and the included angle K between the second inclined cutting edge 221D and the straight cutting edge 221A is 150° to 170°; wherein, the length of the first inclined cutting edge 221B is greater than the length of the second inclined cutting edge 221D; thus providing a transition between the straight cutting edge 221A and the first inclined cutting edge 221B, providing better stress protection for the straight cutting edge 221A and the first inclined cutting edge 221B, and during small feeds, the first inclined cutting edge 221B does not need to participate in cutting, and the second inclined cutting edge 221D can complete the cutting.

[0060] like Figure 6 , 7 As shown, the bottom surface 12 of the main body 1 is also provided with an assembly groove 120, which is used to position and adapt to the mounting part 312 of the tool holder 3. Even if it is in clearance fit with the mounting part 312 on the groove 31, when the tool holder 3 drives the blade to rotate at high speed for processing, the blade is subjected to force so that the side of the mounting groove 120 on the back of the blade is in close contact with the edge of the mounting part 312, resisting the force on the blade in the locked position, and avoiding excessive stress deformation of the locking fastener and displacement of the blade.

[0061] like Figure 2 , 7 As shown, a tool for mounting a high-speed milling insert includes a tool holder 3, a slot 31 formed in the tool holder 3 for mounting the insert, and the insert.

[0062] After the blade is prepared in the above manner, the blade is detachably fixed in the slot 31 by the locking fastener 4 through the central hole 11, and one of the long edge 211 and the short edge 221 of the blade are exposed on the outer peripheral surface and end face of the blade shank 3 respectively. It should be noted that the bottom 311 of the slot 31 is not a plane, but an inclined surface; it is inclined downward along the axial direction of the blade shank 3 towards the end (i.e. outward), and the mounting part 312 protrudes from the inclined surface (bottom 311).

[0063] Furthermore, a recessed countersunk platform 32 is formed in the middle of the end on which the blade is mounted on the tool holder 3, and a clearance groove 33 is formed at the corresponding slot 31, so that the blade can fit against the side walls 313 of the slot 31 when locked. Moreover, since the short edge 221 of the blade has a large slope, it can better process planes or slopes with an inclination angle of 0° to 20° compared to the usual straight cutting edge design. Combined with the recessed countersunk platform 32, the blade and tool body can be used in more flexible and wider processing situations.

[0064] In addition, an internal cooling channel (not shown in the figure) is formed inside the tool holder 3, and the inlet of the internal cooling channel (not shown in the figure) is opened at the end of the tool holder 3 away from the blade. The outlet 5 is located in the groove 31 and faces the long edge 211 and / or the short edge 221. Under normal circumstances, the outlet 5 is aligned with the long edge 211 to quickly cool the long edge 211 participating in the machining. In this embodiment, an internal cooling channel (not shown in the figure) is set in the center of the tool body, and the cross-sectional diameter of the outlet 5 is less than 1 / 4 of the cross-sectional diameter of the inlet. During assembly, the minimum distance between the internal cooling channel (not shown in the figure) and the long edge 211 is <13mm. Oil mist lubrication can also be achieved under special working conditions. The design of the internal cooling channel (not shown in the figure) ensures the cooling effect, improves the machining quality, extends the tool life, and has good dynamic balance ability, making it less prone to tool vibration.

[0065] In actual use, such as Figure 2-9 As shown, the cutting blade is installed in the slot 31 of the tool holder 3 by the fastener 4, and is fitted with the mounting slot 120 by the mounting part 312 to achieve a stable installation; the tool holder 3 drives the two cutting blades installed in the slot 31 to rotate at high speed, and after feeding down to a cutting position, it performs milling along the horizontal plane. At this time, the long edge 211 and the short edge 221 participate in the cutting. Due to the high speed rotation, the envelope formed by the long edge 211 after the design is compensated by the arc-shaped cutting edge segment 211A, so that the envelope is close to a straight line. After cutting in this way, the surface is also close to a straight surface. After feeding to a cutting position again, the surface is also close to the previous cutting position.

[0066] Moreover, the short-side cutting edge 221 has a smaller contact area when cutting a plane, resulting in less force and less risk of vibration and chipping. Therefore, the two surfaces processed simultaneously have higher precision and better surface quality.

[0067] The description of the above specification and embodiments is used to explain the scope of protection of the present invention, but does not constitute a limitation on the scope of protection of the present invention.

Claims

1. A cutting insert for high-speed milling, comprising a body, a central hole formed in the body, a bottom surface, a top surface, and edge surfaces disposed between the bottom surface and the top surface; wherein two of the edge surfaces are configured as long cutting surfaces, and a long edge cutting edge is formed at the position where the long cutting surfaces connect with the top surface; and the other two edge surfaces are configured as short cutting surfaces, and a short edge cutting edge is formed at the position where the short cutting surfaces connect with the top surface; characterized in that: The angle between each of the edge surfaces and the bottom surface is set to an obtuse angle; Each of the long edge blades has an arc-shaped blade segment, and each arc-shaped blade segment protrudes outward along a direction perpendicular to the long edge blade and through its midline; The long blade surface, corresponding to the position of the arc-shaped blade segment, forms an outwardly convex curved surface to support the arc-shaped blade segment; on the transverse cross-section of the main body, the curved surface gradually tapers towards the bottom surface in an arc shape, and the curvature of the curved surface is the same as the calculation formula for the long edge forming; the calculation formula for the long edge forming with the arc-shaped blade segment is: F(S)=π*S*cosβ*cosα / 180*cos(90°-α) Wherein, S is the length of the long edge cutting edge; α is the axial rake angle of the main body mounted on the tool holder; and β is the radial rake angle of the main body mounted on the tool holder.

2. The cutting tool for high-speed milling as described in claim 1, characterized in that: Each of the short edge blades includes a straight edge portion, a first inclined edge portion, and an arc-shaped edge portion; the straight edge portion is connected to the two long edge blades through the first inclined edge portion and the arc-shaped edge portion, and the included angle between the straight edge portion and the first inclined edge portion is 120°~140°.

3. The cutting tool for high-speed milling as described in claim 2, characterized in that: The short edge blade also includes a second inclined blade portion, which is formed between the first inclined blade portion and the straight blade portion, and the included angle between the second inclined blade portion and the straight blade portion is 150°~170°; wherein, the length of the first inclined blade portion is greater than the length of the second inclined blade portion.

4. The cutting tool for high-speed milling as described in claim 3, characterized in that: The bottom surface of the main body is also provided with an assembly groove, which is used to position and adapt to the mounting part of the tool holder.

5. A cutting tool for mounting high-speed milling inserts, comprising a tool holder and a slot formed in the tool holder for mounting the insert; characterized in that: It also includes a blade as described in any one of claims 1-4, wherein the blade passes through the central hole via a locking fastener to detachably fix the blade in the slot, and one of the long edge edges of the blade and the corresponding short edge edge are exposed on the outer peripheral surface and end face of the tool holder.

6. A cutting tool equipped with a high-speed milling insert as described in claim 5, characterized in that: The bottom surface of the blade body is also provided with an assembly groove. The bottom of the groove slopes outward from the axial direction of the blade holder, and the bottom of the groove protrudes to form a mounting part that fits the assembly groove with a clearance.

7. A cutting tool equipped with a high-speed milling insert as described in claim 6, characterized in that: A concave recess is formed in the middle of the end of the blade mounted on the tool holder; the two slots are arranged symmetrically with respect to the center of the concave recess, and a clearance groove is formed at each slot.

8. A cutting tool equipped with a high-speed milling insert as described in claim 5, characterized in that: The tool holder also has an internal cooling channel formed inside, and the liquid inlet of the internal cooling channel is opened at the end of the tool holder away from the blade, and the liquid outlet is located in the groove and faces the long edge and / or the short edge.

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