End mill

Abstract

This invention provides an end mill in which at least one of its plurality of peripheral cutting edges (20a) to (20c) is a convex-concave cutting edge. This convex-concave cutting edge is provided with a convex-concave edge (Er) composed of a notching edge or a roughing edge. Since the convex-concave edge (Er) is only provided on a portion of the cutting edge length (L) of the convex-concave cutting edge, the magnitude of the cutting force differs depending on whether the convex-concave edge (Er) is present. That is, since the cutting force is smaller in the portion with the convex-concave edge (Er), resonance is suppressed by this difference in cutting force. Even in an end mill (10) with equal lead and equal helix angles of the plurality of peripheral cutting edges (20a) to (20c), chatter caused by resonance can be suppressed.

Description

Technical Field

[0001] This invention relates to end mills, and particularly to a new technique for effectively suppressing chatter. Background Technology

[0002] If chatter occurs during machining with an end mill, the cutting speed is limited or the surface roughness of the machined surface is compromised. To suppress such chatter, end mills with unequal leads and multiple peripheral cutting edges having different helix angles have been proposed. The end mill described in Patent Document 1 is one example; as the helix angle varies, the direction and magnitude of the cutting force (resistance) differ, and the spacing between the cutting edges also changes, thereby suppressing resonance and the chatter that arises from it.

[0003] Prior art literature

[0004] Patent documents

[0005] Patent Document 1: Japanese Patent Application Publication No. 63-89212 Summary of the Invention

[0006] The problem that the invention aims to solve

[0007] However, because multiple peripheral cutting edges with different helix angles in such unequal lead end mills may interfere with each other, the cutting edge length, number of cutting edges, and helix angle difference are constrained, making the design of tools with helix angles troublesome, and sometimes chatter cannot be properly prevented. Figure 38 This is a unfolded diagram illustrating the interference (crossing) of the outer peripheral cutting edges shown as edges 1 to 6. The top is the shank side, and the bottom edge side is the bottom edge side. All are right-hand helical cuts, driven by rotation to the right when viewed from the shank side. In the case of the three edges at the left end, there is interference between edge 3 and edge 1 due to a large difference in helix angle. In the case of the six edges in the center, there is interference between adjacent edges 2 and 3, edge 4 and edge 5, and edge 6 and edge 1 due to narrow spacing. In the case of the four edges at the right end with long edges, even with a relatively small difference in helix angle, there is interference between adjacent edges 2 and 3, and edge 4 and edge 1.

[0008] The present invention was made against the background described above, and its purpose is to provide a novel end mill with different helix angles and unequal leads that is effective in suppressing chatter.

[0009] Solution for solving the problem

[0010] To achieve the above objectives, the first invention is an end mill having a plurality of peripheral cutting edges, characterized in that: (a) the helix angles of the plurality of peripheral cutting edges are equal to each other; and (b) at least one of the plurality of peripheral cutting edges is a convex-concave cutting edge, which is provided with convex-concave edges composed of notching edges or roughing edges; (c) the convex-concave edges are provided only in a portion of the cutting length of the convex-concave cutting edge; and (d) the convex-concave cutting edge is any one of cutting edge A, cutting edge B, and cutting edge C, wherein cutting edge A is provided with the convex-concave edges in a range of 5% to 65% of the cutting length within a range of 70% of the cutting length from the shank side end toward the bottom edge side in the tool axial direction. The cutting edge B has the concave-convex edge provided in the tool axis from the bottom edge side end toward the tool holder side in a range of 70% of the cutting edge length, and in a range of 5% to 65% of the cutting edge length. The cutting edge C has the concave-convex edge provided in the tool axis from the center of the cutting edge length toward two directions in the tool axis in a range of 35% of the cutting edge length, and in a range of 5% to 65% of the cutting edge length. (e) The plurality of peripheral cutting edges are any of the four types of cutting edges A to D, namely the cutting edges A to C with concave-convex edges and the cutting edge D without concave-convex edges, and are configured to include two or more types in such a way that adjacent peripheral cutting edges are different types. (f) The helix angle of the plurality of peripheral cutting edges is in the range of 0° to 5°.

[0011] Furthermore, the outer peripheral cutting edge does not necessarily have to be a helical edge; it can also be a straight edge with a helix angle of 0°. Additionally, it is independent of the helix direction; it can be either a right-handed or left-handed helix, as long as it falls within the range of 0° to 5°, and the combined angle of the two directions must be within 10°.

[0012] The second invention is that, in the end mill of the first invention, the surface of the cutting edge on which the plurality of peripheral cutting edges are provided is covered with a hard coating.

[0013] Invention Effects

[0014] In such an end mill, at least one of the multiple peripheral cutting edges is a convex-concave cutting edge. This convex-concave cutting edge is provided with a concave-concave edge composed of a notching edge or a roughing edge, and this concave-concave edge is only provided on a portion of the cutting length of the convex-concave cutting edge. Therefore, the magnitude of the cutting force is partially different depending on whether the concave-concave edge is provided. That is, the cutting force is smaller in the portion where the concave-concave edge is provided. Therefore, resonance is suppressed by the difference in cutting force. Even in an end mill where the helix angles of the multiple peripheral cutting edges are equal, chatter caused by resonance can be suppressed.

[0015] Furthermore, since the cutting edge is provided with any of the three types of cutting edges A, B, and C, the range of the three types of cutting edges A, B, and C with concave and convex edges is all within the range of 5% to 65% of the cutting edge length, and the positions of the concave and convex edges are different, chatter can be appropriately suppressed by the change in the magnitude of the cutting force caused by the presence or absence of concave and convex edges.

[0016] Furthermore, the multiple peripheral cutting edges are any of the four types of cutting edges A to D, namely cutting edges A to C and cutting edge D without concave or convex edges. They are configured such that adjacent peripheral cutting edges are of two or more different types. Therefore, the presence or absence of concave or convex edges, and their positions, differ between adjacent peripheral cutting edges, thus enabling more appropriate suppression of chatter. Additionally, while concave or convex edges might cause burrs to form on the surface of the workpiece, the configuration, including two or more types of cutting edges with different positions and without concave or convex edges, effectively suppresses burr formation.

[0017] Furthermore, since the helix angle is relatively small in the range of 0° to 5°, the feed force becomes larger, which easily leads to vibration. Therefore, by providing a cutting edge with concave and convex edges, the vibration suppression effect of the present invention can be significantly achieved. Additionally, if the helix angle is small, melting is more likely to occur, thus limiting the cutting speed. However, by using the concave and convex edges to cut the chips, melting is suppressed, alleviating the limitation on cutting speed, thereby enabling high-speed (high-rotation) machining. Furthermore, if a cutting edge with concave and convex edges is provided, chipping is more likely to occur when the helix angle becomes larger. However, by keeping the helix angle below 5°, chipping can be suppressed, which also enables high-speed (high-rotation) machining.

[0018] In the second invention, since the surface of the cutting edge with multiple peripheral cutting edges is covered with a hard coating, excellent cutting durability can be obtained even though there are some uneven edges. Attached Figure Description

[0019] Figure 1 This is a schematic perspective view showing an end mill as an embodiment of the present invention.

[0020] Figure 2 This is to explain as Figure 1 The end mill has three outer peripheral cutting edges and uses four types of cutting edges A to D.

[0021] Figure 3 It is to be used as Figure 2 The diagram illustrates a comparison between the notched and rough-machined cutting edges (Er type) and ordinary cutting edges.

[0022] Figure 4 It is an explanation Figure 2 The four cutting edges A through D are used to construct three of them. Figure 1 The figure shows a specific example of an end mill with three peripheral cutting edges.

[0023] Figure 5 This example includes Figure 4 The diagram shows a combination of multiple peripheral cutting edges, consisting of four types of cutting edges A to D, including specific examples.

[0024] Figure 6 Is Figure 1 The three outer peripheral cutting edges of the end mill are composed of Figure 2 The diagram shows the unfolded shape of the outer peripheral cutting edges, which are composed of cutting edges A, B, and D, about the axis.

[0025] Figure 7 This diagram illustrates an embodiment where the three outer peripheral cutting edges are left-handed helical, and is related to... Figure 6 The corresponding unfolded diagram.

[0026] Figure 8 This diagram illustrates an embodiment with three unequally spaced outer peripheral cutting edges, and is related to... Figure 6 The corresponding unfolded diagram.

[0027] Figure 9 This diagram illustrates the direction and magnitude (coarseness) of the cutting force generated by the three outer peripheral cutting edges by comparing the product of this invention with existing products with unequal leads.

[0028] Figure 10 This diagram illustrates the three test specimens No.1 to No.3 used in the cutting test.

[0029] Figure 11 This is a diagram illustrating the resultant force F of the resistance values ​​measured in the cutting test.

[0030] Figure 12 It is a diagram illustrating the positional relationship between the material being cut and the tool in a cutting experiment.

[0031] Figure 13 This is a graph illustrating the amplitude of the resultant force F of the resistance values ​​measured in the cutting test.

[0032] Figure 14 This is a diagram illustrating the machining conditions for the cutting test.

[0033] Figure 15 This means that in Figure 14 The graph shows the amplitude and ratio of the resultant force F of the resistance values ​​of test specimens No1 to No3, which were measured under the machining conditions.

[0034] Figure 16 Using charts to... Figure 15 The graph shows a comparison of the amplitudes of test samples No.1 to No.3 under condition 1.

[0035] Figure 17 According to Figure 14 The figure is shown by comparing the vibration waveform of the resultant force F of the resistance values ​​of test specimens No.1 to No.3 measured during the cutting process under condition 1.

[0036] Figure 18 Using charts to... Figure 15 The graph shows a comparison of the amplitudes of test samples No1 to No3 under condition 2.

[0037] Figure 19 According to Figure 14 The figure is shown by comparing the vibration waveform of the resultant force F of the resistance values ​​of test specimens No1 to No3 measured during the cutting process under condition 2.

[0038] Figure 20 This is an explanation of the use and Figure 10 The diagram shows the machining conditions under which the same test specimens No.1 to No.3 were subjected to other cutting tests with different materials.

[0039] Figure 21 This means that in Figure 20 The graph shows the amplitude and ratio of the resultant force F of the resistance values ​​of test specimens No1 to No3, which were measured under the machining conditions.

[0040] Figure 22 Using charts Figure 21 The graph shows a comparison of the amplitudes of test samples No.1 to No.3.

[0041] Figure 23 According to Figure 20 The figure is shown by comparing the vibration waveform of the resultant force F of the resistance values ​​of test specimens No.1 to No.3 measured during cutting under the processing conditions.

[0042] Figure 24 It is a diagram illustrating the cutting edge shapes of the six test samples No.1 to No.6.

[0043] Figure 25 This is an instruction on how to use. Figure 24 The diagram shows the machining conditions for the cutting tests conducted on test specimens No.1 to No.6.

[0044] Figure 26 This means that in Figure 25 The graph shows the results of a cutting experiment conducted under different machining conditions while changing the cutting speed. It also shows whether the machine could not be machined due to excessive vibration at each cutting speed, indicated by ○×.

[0045] Figure 27This is a diagram illustrating the cutting edge shapes of three test samples No.1 to No.3.

[0046] Figure 28 This is an instruction on how to use. Figure 27 The diagram shows the machining conditions for cutting tests on test samples No.1 to No.3.

[0047] Figure 29 According to Figure 28 The figure is shown by comparing the vibration waveform of the resultant force F of the resistance values ​​of test specimens No1 to No3 measured during cutting under the processing conditions.

[0048] Figure 30 This is an explanation of the use and Figure 27 The diagram shows the machining conditions under which the same test specimens No.1 to No.3 were subjected to other cutting tests with different materials.

[0049] Figure 31 According to Figure 30 The figure is shown by comparing the vibration waveform of the resultant force F of the resistance values ​​of test specimens No1 to No3 measured during cutting under the processing conditions.

[0050] Figure 32 It is a diagram illustrating the cutting edge shapes of eight test samples No.1 to No.8.

[0051] Figure 33 To explain in more detail Figure 32 Diagrams showing the cutting edge shapes of test specimens No.5 to No.8.

[0052] Figure 34 This is an instruction on how to use. Figure 32 The diagram shows the machining conditions for the cutting tests conducted on test specimens No.1 to No.8.

[0053] Figure 35 This means that in Figure 34 The graph shows the test results obtained by performing cutting tests while changing the cutting speed under the processing conditions, and it shows the judgment results related to welding and chipping at each cutting speed.

[0054] Figure 36 It specifically shows the... Figure 32 Cutting tests were conducted on test samples No. 2 and No. 6, and observations were made. Figure 37 The diagram shows the presence or absence of fusion deposition and the processing conditions during chip removal.

[0055] Figure 37 This is an explanation based on Figure 36 The figure shows the test results of the machining conditions, and is a photograph illustrating the presence or absence of welding on the rake face and the chips.

[0056] Figure 38 This diagram illustrates the interference of the peripheral cutting edge of an existing product with unequal leads. Detailed Implementation

[0057] The end mill of this invention can be either a right-hand rotating end mill driven to perform cutting operations when viewed from the shank side, or a left-hand rotating end mill driven to perform cutting operations. The number of cutting edges is widely used to be 3 to 5, but it can also be applied to end mills with 2 or more cutting edges. The outer peripheral cutting edge can be a straight cutting edge with a helix angle of 0°, or a right-hand or left-hand helical cutting edge.

[0058] The end mill of this invention is suitable for finishing (peripheral cutting) of FRP (fiber reinforced plastic) materials such as CFRP (carbon fiber reinforced plastic) and CFRTP (carbon fiber reinforced thermoplastic), but can also be used for cutting other materials such as steel. As the material for the end mill, materials such as superhard alloys and high-hardness sintered bodies are suitable, but other hard tool materials such as high-speed tool steel can also be used. A hard coating can be applied as needed to improve cutting durability. As the hard coating, in addition to intermetallic compounds, diamond coatings can also be used. As the intermetallic compound, metals from Groups 4, 5, 6, and 13 of the periodic table are suitable, such as carbides, nitrides, carbonitrides, or their mutual solid solutions, including Al, Ti, V, and Cr. Specifically, TiN, TiAlN, TiCN, TiCrN, and AlCrN are suitable. Such hard coatings of intermetallic compounds are suitable for being formed by PVD methods such as arc ion plating and sputtering, but can also be formed by other film formation methods such as plasma CVD.

[0059] Example

[0060] Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings. Furthermore, in the following embodiments, for illustrative purposes, the drawings have been appropriately simplified or modified, and the dimensions and shapes of the parts may not be precisely depicted.

[0061] Figure 1This is a perspective view of an end mill 10 according to an embodiment of the present invention. The end mill 10 has a shank 12 and a cutting edge 14 concentrically arranged. Three peripheral cutting edges 20a, 20b, and 20c (hereinafter referred to as peripheral cutting edges 20 unless otherwise specified) are formed by providing three grooves on the cutting edge 14. At the front ends of the three peripheral cutting edges 20a, 20b, and 20c, bottom cutting edges 22a, 22b, and 22c (hereinafter referred to as bottom cutting edges 22 unless otherwise specified) are continuously provided. The end mill 10 performs cutting operations by being driven to rotate to the right when viewed from the shank 12 side. The end mill 10 is made of superhard alloy, and the surface of the cutting edge 14 is coated with a hard coating 24, such as a diamond coating. Figure 1 The slashed part indicates a rigid coating 24.

[0062] At least one of the three peripheral cutting edges 20 is a convex-concave cutting edge with a concave-convex edge Er consisting of a notched edge or a roughing edge. Figure 1 In the middle, the two outer peripheral cutting edges 20a and 20b are cutting edges with concave and convex edges Er. Figure 2 Cutting edges A, B, and C are specific examples of cutting edges with concave and convex edges Er. The figure shows the case where Er is used as a roughing edge. Figure 2 The cutting edge D is a normal cutting edge without a concave or convex edge Er. Figure 3 This diagram illustrates a comparison between notched cutting edges (Er) and roughing cutting edges (Er) and ordinary cutting edges. It is an enlarged photograph viewed from the rake face side. Ordinary cutting edges are smooth, typical cutting edges without notches (grooves), roughing portions (ripples), and fixed outer diameter dimensions.

[0063] exist Figure 2In the tool axial direction, cutting edge A has a raised / lower edge Er along the tool shank side from the end towards the bottom edge, within a range of 70% (0.7L) of the cutting length L and within a range of 5% to 65% (0.05L to 0.65L) of the cutting length L. Cutting edge B has a raised / lower edge Er along the tool axial direction from the end towards the tool shank side, within a range of 70% (0.7L) of the cutting length L and within a range of 5% to 65% (0.05L to 0.65L) of the cutting length L. Cutting edge C has a raised / lower edge Er along the tool axial direction from the center of the cutting length L in two directions, within a range of 35% (0.35L) of the cutting length L and within a range of 5% to 65% (0.05L to 0.65L) of the cutting length L. Furthermore, the three peripheral cutting edges 20 of the end mill 10 in this embodiment are any of the four types of cutting edges A to D, namely cutting edges A to C with concave and convex edges and cutting edge D without concave and convex edges Er. They are configured to include two or more types, with adjacent peripheral cutting edges 20 being of different kinds. The end mill 10 of this embodiment, which has three edges, has three peripheral cutting edges 20 composed of three different types of cutting edges A to D. Figure 1 In the diagram, the outer peripheral cutting edge 20a is cutting edge A, the outer peripheral cutting edge 20b is cutting edge B, and the outer peripheral cutting edge 20c is cutting edge D. However, it can also be as follows: Figure 4 It can be formed in various ways as illustrated. Figure 4 Edge 1 to Edge 3 represent three outer peripheral cutting edges 20a to 20c. "A" to "D" in the diagram indicate... Figure 2 The cutting edge is "cutting edge A" to "cutting edge D". In addition, it can be a combination of "cutting edge A", "cutting edge C" and "cutting edge D", or a combination of "cutting edge B", "cutting edge C" and "cutting edge D".

[0064] Figure 5 The diagram illustrates end mills with three, four, and five cutting edges, constructed by including two or more cutting edges A through D and making adjacent peripheral cutting edges different types.

[0065] On the other hand, the helix angles of the three outer peripheral cutting edges 20a, 20b, and 20c are equal to each other. Furthermore, the helix angles of the three outer peripheral cutting edges 20a, 20b, and 20c are within the range of 0° to 5°, and can be either right-hand or left-hand helical, with the two directions defined within a total range of 10°. In this embodiment, the three outer peripheral cutting edges 20a, 20b, and 20c are either straight cutting edges with a helix angle of 0° or right-hand helical cutting edges with a helix angle of less than 5° in the right-hand helical direction, so that the chips are discharged towards the tool holder 12 side. Figure 6 This is an unfolded diagram, which shows that the three outer peripheral cutting edges 20a, 20b, and 20c of the end mill 10 are respectively composed of... Figure 2In the case of cutting edges A, B, and D, these peripheral cutting edges 20a, 20b, and 20c are unfolded around the axis. Edges 1 to 3 correspond to peripheral cutting edges 20a to 20c, respectively, and the dotted lines represent the concave-convex cutting edges Er. Furthermore, the helix angles α1 to α3 (hereinafter, unless otherwise specified, simply referred to as helix angle α) of edges 1 to 3 are α1 = α2 = α3, and these peripheral cutting edges 20a, 20b, and 20c are arranged at equal intervals in the circumferential direction. That is, the intervals D1 to D3 (hereinafter, unless otherwise specified, simply referred to as interval D) of edges 1 to 3 are D1 = D2 = D3. Figure 6 This is the case where the helix angle α1 to α3 is about 25°. However, setting the helix angle α1 to α3 to less than 5° is an embodiment of the present invention. Figures 1-4 The helix angle is also around 20°, but the case where it is set to less than 5° is an embodiment of the present invention.

[0066] Figure 7 Is with Figure 6 In the corresponding unfolded diagram, when the outer peripheral cutting edge 30 is a left-handed helix, the helix angles β1 to β3 are all within the range of 0° to 5° and β1 = β2 = β3. In addition, the three edges 1 to 3 of the outer peripheral cutting edge 30 are arranged at equal intervals in the circumferential direction, with D1 = D2 = D3.

[0067] Figure 8 Is with Figure 6 In the corresponding unfolded diagram, the outer peripheral cutting edge 40, like the aforementioned outer peripheral cutting edge 20, is a right-hand helix, with helix angles α1 to α3 ranging from 0° to 5° and α1 = α2 = α3. However, the three edges 1 to 3 of this outer peripheral cutting edge 40 are arranged at unequal intervals in the circumferential direction, with D1 ≠ D2 ≠ D3. Even if there is only one different case among the intervals D1 to D3, the intervals are still unequal. These outer peripheral cutting edges 30 and 40 are also an embodiment of the present invention. Figure 7 The outer peripheral cutting edge 30 of the left-hand helix can also be unequally spaced.

[0068] According to this end mill 10, since at least one of the multiple cutting edges 1 to 3 of the outer peripheral cutting edges 20, 30, and 40 is a convex-concave cutting edge with a concave-convex edge Er composed of a notching edge or a roughing edge, and since this concave-convex edge Er is only provided on a portion of the cutting edge length L of the convex-convex cutting edge, the magnitude of the cutting force is partially different depending on the presence or absence of the concave-convex edge Er. That is, since the cutting force is smaller in the portion where the concave-convex edge Er is provided, resonance is suppressed by this difference in cutting force. Even in an end mill 10 with equal lead and equal helix angles α and β of the outer peripheral cutting edges 20, 30, and 40, chatter caused by resonance can be suppressed. As a result, the surface roughness is improved, and high cutting speed (high rotational speed) cutting is possible.

[0069] Furthermore, when any of the three types of cutting edges A, B, and C with concave and convex edges Er located in different positions within the range of 5% to 65% of the cutting length L is used as a cutting edge with concave and convex edges Er, chatter can be appropriately suppressed by the change in the magnitude of the cutting force caused by the presence or absence of the concave and convex edges Er.

[0070] In addition, for example, Figure 4 , Figure 5 As shown, the multiple peripheral cutting edges 20 (edges 1 to 5) are any of the four types of cutting edges A to D: cutting edges A to C and cutting edge D without a concave or convex edge Er. Furthermore, they are composed of two or more types of cutting edges A to D, with adjacent peripheral cutting edges representing different types. In this case, since the presence or absence of a concave or convex edge Er and the position of the concave or convex edge Er differ between adjacent peripheral cutting edges 20, chatter can be suppressed more effectively. Additionally, if a concave or convex edge Er is provided, burrs may be generated on the surface of the workpiece. However, since the cutting edges are composed of three types of cutting edges with or without a concave or convex edge Er and different positions, burr formation can be suppressed.

[0071] Furthermore, in this embodiment, the helix angles α and β are relatively small within the range of 0° to 5°, which increases the feed force and makes vibration more likely. Therefore, by making at least one of the cutting edges 1 to 3 of the outer peripheral cutting edges 20, 30, and 40 a convex-concave cutting edge with an convex-concave edge Er, the vibration suppression effect can be significantly achieved. Additionally, if the helix angles α and β are small, melting is more likely to occur, thus limiting the cutting speed. However, by cutting the chips with the convex-concave edge Er, melting can be suppressed, and the limitation on cutting speed is alleviated, thereby enabling high-speed (high-rotation) machining. Furthermore, if cutting edges A to C with convex-concave edges are provided, chipping is more likely to occur when the helix angles α and β become large. However, by setting the helix angles α and β to 5° or less, chipping can be suppressed, and high-speed (high-rotation) machining can also be performed.

[0072] Furthermore, since the surface of the cutting edge 14 with the outer peripheral cutting edges 20, 30, and 40 is covered by a hard coating 24, excellent cutting durability can be obtained even with the presence of some uneven edges Er.

[0073] Figure 9 This is for those who have the above Figure 6 The present invention product and the existing product with unequal lead of the end mill 10 with the outer peripheral cutting edge 20 shown are illustrated in the developed diagram of the three outer peripheral cutting edges (edge ​​1 to edge 3), with the cutting force diagram indicated by white arrows. The direction of the white arrows indicates the direction of the cutting force, and the thickness indicates the magnitude of the cutting force. The present invention product and the existing product with unequal lead are illustrated in the developed diagram of the end mill 10 with the three outer peripheral cutting edges 20. Figure 6 The same, the three blades 1 to 3 are made by Figure 2The cutting edge consists of cutting edge A, cutting edge B and cutting edge D. In this case, since the cutting force of the cutting edge 1 and cutting edge 2 is reduced in the part where the concave and convex cutting edge Er is provided, the resonance is suppressed by the difference in the cutting force, so that the vibration reduction effect can be obtained as appropriately as existing products with unequal leads.

[0074] The following describes several cutting experiments conducted to specifically illustrate the effects of the present invention.

[0075] Figure 10 This diagram illustrates the cutting edge shapes of test specimens No. 1 to No. 3 used in the cutting tests. Edges 1 to 3 correspond to three outer peripheral cutting edges 20a to 20c. Test specimen No. 1 is made solely of the aforementioned cutting edges without concave or convex edges Er. Figure 2 The existing products have a cutting edge D. Test items No. 2 and No. 3 are products of the present invention with a roughing edge, having a convex-concave cutting edge Er. Test item No. 2 has three edges 1 to 3 formed by the above... Figure 2 The cutting edge consists of cutting edge A, cutting edge B, and cutting edge D. The three cutting edges 1 to 3 of test sample No. 3 are composed of the above... Figure 2 The cutting edge consists of cutting edge A, cutting edge B, and cutting edge C. The percentage in parentheses for each cutting edge is the ratio of the length of the concave-convex edge Er to the cutting edge length L. Cutting edges A, B, and C, which have concave-convex edges Er, all have a percentage of 60%. In these test specimens No.1 to No.3, all three edges 1 to 3 are right-hand helical edges with a helix angle α of 5°, a cutting edge length L of 12 mm, and a cutting edge diameter Φ of 6 mm. Figure 11 This is a graph illustrating the resultant force F of the resistance values ​​measured in the cutting test, along with the feed component Fx in the tool feed direction and the machining surface Wf (refer to...). Figure 12 The resultant force F is the principal component force Fy in the right-angle direction and the back component force Fz in the tool axis (the thickness direction of the material being cut). This resultant force F corresponds to the load applied to the workpiece W. Figure 12 This diagram illustrates the positional relationship between the workpiece W and the tool T during a cutting test. The outer circumferential surface of the workpiece W is trimmed at a position where it protrudes 30mm from the worktable. Figure 13 This is a graph illustrating the amplitude of the resultant force F, which represents the resistance values ​​measured in a cutting test. The width between the maximum and minimum values ​​of the resultant force F is the amplitude.

[0076] Then, in Figure 14 Under the two machining conditions shown (condition 1 and condition 2), CFRTP, as the workpiece material, was dressed. The resultant force F and its amplitude were measured and calculated. Figure 15 In conditions 1 and 2, the cutting speed and feed per edge are different. Compared with condition 1, condition 2 has a faster cutting speed and a smaller feed per edge. Figure 15This is a graph showing the ratio of the amplitude of the measured resultant force F to the amplitude of test sample No.1 (existing product) as 100%. Figure 15 It can be seen that, under condition 1 (cutting speed of 200 m / min and feed per cutting edge of 0.08 mm / t), the amplitude of the product of the present invention according to test specimen No. 2 is reduced by about 22%, and the amplitude of the product of the present invention according to test specimen No. 3 is reduced by about 41%. Furthermore, under condition 2 (cutting speed faster than condition 1 and feed per cutting edge smaller), the amplitude of the product of the present invention according to test specimen No. 2 is reduced by about 70%, and the amplitude of the product of the present invention according to test specimen No. 3 is reduced by about 80%, demonstrating a significant vibration reduction effect. Figure 16 The graph is shown by comparing the amplitude under condition 1. Figure 17 This is a graph showing the actual vibration waveform compared to the measured resistance value of the resultant force F. Figure 18 The graph is shown by comparing the amplitude under condition 2. Figure 19 This is a graph showing the actual vibration waveform compared to the measured resistance value of the resultant force F. Furthermore, the test specimens No.1 to No.3 used here have a diamond coating as a hard coating 24.

[0077] Figure 20 Is it used with Figure 10 The same test specimens No.1 to No.3 were subjected to other cutting tests on different cut materials under different conditions. Here, S50C (carbon steel for mechanical structures) was subjected to side cutting with a feed rate ap (axial) = 6 mm and a feed rate ae (radial) = 0.6 mm. Figure 21 The graph shows the ratio of the amplitude of the measured resultant force F to that of test sample No. 1 as 100%. According to test sample No. 2, the amplitude of the product of the present invention is reduced by about 12%, and according to test sample No. 3, the amplitude of the product of the present invention is reduced by about 19%. Figure 22 Comparison via charts Figure 21 The graph shown is based on the amplitude of the vibration. Figure 23 This is a graph showing the actual vibration waveforms of the measured resultant force F resistance values. Furthermore, the test samples No.1 to No.3 used here have a Cr-based intermetallic compound as a hard coating 24.

[0078] Figures 24-26 This is a diagram that further illustrates the test results of other cutting processes. Figure 24 This diagram illustrates six different cutting edge shapes (No. 1 to No. 6) corresponding to the three cutting edges 1 to 3 of the aforementioned peripheral cutting edges 20a to 20c. Test No. 1 is made solely of the aforementioned cutting edge without the concave-convex edge Er. Figure 2The existing product consists of a cutting edge D. Test items No. 2 to No. 6 are cutting edges with three blades, blades 1 to 3, which are roughing edges set as convex and concave cutting edges Er, and are composed of the above-mentioned... Figure 2 Cutting edges A, B, and C are identical in composition, but the ratio of the length of the concave-convex edge Er to the blade length L differs: 5% for test sample No. 2, 25% for test sample No. 3, 45% for test sample No. 4, 65% for test sample No. 5, and 85% for test sample No. 6. Test samples No. 2 to No. 5 are products of this invention, while test sample No. 6 is a comparative product. All three edges 1 to 3 of these test samples No. 1 to No. 6 are right-hand helical edges with a helix angle α of 5°, a blade length L of 12 mm, and a blade diameter Φ of 6 mm. Furthermore, a diamond coating is used as the hard coating 24.

[0079] In addition, Figure 25 Under the shown machining conditions, cutting speed was varied while machining was performed, and the occurrence of chatter was observed. Figure 26 The results are shown. (By...) Figure 26 It can be seen that in the existing product test specimen No.1, chattering becomes excessive and machining becomes impossible when the cutting speed is 150 m / min or higher. In contrast, in the present invention test specimens No.2 to No.5, the vibration is small and stable machining is possible under all conditions of cutting speed from 50 to 400 m / min. Furthermore, in the test specimen No.6, where the ratio of the concave-convex edge (Er) is 85%, chattering becomes excessive and machining becomes impossible when the cutting speed is 250 m / min or higher. Based on these test results, it can be seen that the present invention test specimens No.2 to No.5, which have concave-convex edge cutting edges (cutting edges A to C) with concave-convex edge (Er), can suppress chattering. If the ratio of the concave-convex edge (Er) is high, chattering may occur at high cutting speeds (high rotational speeds). Therefore, it is preferable that the ratio of the length of the concave-convex edge (Er) to the cutting length (L) is preferably in the range of approximately 5% to 65%.

[0080] Figures 27-29 This is a diagram that further illustrates the test results of other cutting processes. Figure 27 This diagram illustrates three test specimens No.1 to No.3 with different cutting edge shapes, corresponding to the three cutting edges 1 to 3 of the aforementioned peripheral cutting edges 20a to 20c. Test specimens No.1 to No.3 are all cutting edges with a roughing edge as a convex-concave edge Er. The three cutting edges 1 to 3 of test specimen No.1 are as described above... Figure 2 The test sample No. 2 consists of three cutting edges: A, B, and C. The three cutting edges 1 to 3 of the test sample No. 2 are composed of the above-mentioned cutting edges. Figure 2 The test specimen No. 3 consists of two types of cutting edges, A and B. The three cutting edges 1 to 3 of the test specimen No. 3 are composed of the above-mentioned... Figure 2The device consists of two cutting edges, A and C. Test product No. 1 is the product of this invention, while test products No. 2 and No. 3 are comparative products. The percentage within parentheses for each cutting edge represents the ratio of the length of the concave-convex edge Er to the edge length L, which is always 60%. All three edges 1 to 3 of these test products No. 1 to No. 3 are right-hand helical edges with a helix angle α of 5°, an edge length L of 12 mm, and an edge diameter Φ of 6 mm.

[0081] also, Figure 29 The text shows that in Figure 28 The actual vibration waveform, amplitude, and ratio of the resistance value of the resultant force F under the machining conditions shown are obtained by measuring the resistance value of the resultant force F. (From...) Figure 29 It can be seen that, compared with test specimen No. 1, which consists of three cutting edges A, B, and C, the amplitude of test specimen No. 2, which consists of two cutting edges A and B, is increased by about 28%, and the amplitude of test specimen No. 3, which consists of two cutting edges A and C, is increased by about 22%. Based on these test results, it is preferable to use three cutting edges A, B, and C to form three blades 1 to 3, with adjacent cutting edges being different types of convex and concave cutting edges. Furthermore, the test specimens No. 1 to No. 3 used here have a diamond coating as a hard coating 24.

[0082] Figure 30 Is it used with Figure 27 The same test specimens No.1 to No.3 were subjected to other cutting tests with different cutting materials under different conditions. Here, S50C (carbon steel for mechanical structures) was subjected to side cutting with a feed rate ap (axial) = 6 mm and a feed rate ae (radial) = 0.15 mm. Figure 31 This graph shows the actual vibration waveform, amplitude, and ratio of the measured resultant force F to the resistance value, with the amplitude of test sample No. 1 as 100%. Compared to test sample No. 1, which consists of three cutting edges A, B, and C, the amplitude of test sample No. 2, which consists of two cutting edges A and B, increases by about 12%, and the amplitude of test sample No. 3, which consists of two cutting edges A and C, increases by about 15%. Therefore, from the test results, it is preferable to use three cutting edges A, B, and C to construct the three cutting edges 1 to 3, so that adjacent cutting edges are different types of convex and concave cutting edges. Furthermore, the test samples No. 1 to No. 3 used here have a Cr-based intermetallic compound as a hard coating 24.

[0083] Figures 32-35 This is a diagram that further illustrates the test results of other cutting processes. Figure 32This diagram illustrates eight test specimens (No. 1 to No. 8) of end mills with different cutting edge shapes, each with three cutting edges. Test specimens No. 1 to No. 4 all have three cutting edges (edges 1 to 3), but without the aforementioned concave-convex edge (Er). Figure 2 The existing products, consisting of cutting edges D, differ only in their helix angle α. Specifically, test item No. 1 is a straight cutting edge with a helix angle α of 0°, test item No. 2 is a right-hand helix cutting edge with a helix angle α of 15°, test item No. 3 is a right-hand helix cutting edge with a helix angle α of 30°, and test item No. 4 is a right-hand helix cutting edge with a helix angle α of 45°. Furthermore, test items No. 5 to No. 8 are cutting edges with concave and convex edges, such as those with a roughing edge provided as a concave-convex edge Er. Figure 33 As specifically shown, all of them have three blades, blades 1 to 3, as described above. Figure 2 The device consists of three cutting edges, A, B, and C, with the ratio of the concave / convex edge Er to the cutting edge length L of these cutting edges A, B, and C being 60%, differing only in the helix angle α. Specifically, test piece No. 5 is a straight cutting edge with a helix angle α of 0°, test piece No. 6 is a right-hand helix cutting edge with a helix angle α of 15°, test piece No. 7 is a right-hand helix cutting edge with a helix angle α of 30°, and test piece No. 8 is a right-hand helix cutting edge with a helix angle α of 45°. Test piece No. 5 is the product of this invention, while test pieces No. 6 to No. 8 are comparative products. The cutting edge length L of these test pieces No. 1 to No. 8 is 12 mm, and the hard coating 24 has a diamond coating.

[0084] In addition, Figure 34 Under the shown machining conditions, cutting was performed while changing the cutting speed. The presence of weld penetration, the amount of weld penetration, and the presence of chipping were observed to obtain the desired results. Figure 35 The results are shown. (By...) Figure 35 It can be seen that in test specimen No. 1, which has a helix angle α of 0° and consists only of a cutting edge D without a concave or convex edge Er, a significant amount of weld penetration was observed at a cutting speed of 150 m / min or higher. Furthermore, in test specimen No. 4, with a helix angle α of 45°, no weld penetration or chipping issues were observed under all cutting speed conditions from 50 to 400 m / min. However, in test specimens No. 2 and No. 3, weld penetration was observed at cutting speeds of 300 m / min or higher. On the other hand, in test specimens No. 5 to No. 8, with a helix angle α of 45°, chipping was observed in test specimen No. 8 when the cutting speed reached 300 m / min or higher. However, in test specimens No. 5 to No. 7, with helix angles α of 0° to 30°, no weld penetration or chipping issues were observed under all cutting speed conditions from 50 to 400 m / min. That is, in the case of test specimens No5 to No8 with a convex-concave cutting edge (cutting edge A to C) provided with a concave-convex edge Er, although the chip can be cut off by the concave-convex edge Er to prevent melting, if the helix angle α increases, chipping is likely to occur. Therefore, the helix angle α is preferably in the range of about 0° to 30°.

[0085] Figure 37 Examples are shown in photographs of test specimens No. 2 and No. 6 with a helix angle α of 15°, taken at a cutting speed of 400 m / min, showing whether there is weld or chips on the rake face. Figure 36 This diagram specifically illustrates the machining conditions for the cutting process at this point. Figure 37 In the existing product, prototype No. 2, which consists only of a cutting edge D without a concave-convex edge (Er), the chips became larger, confirming the presence of weld penetration on the rake face. In prototype No. 6, the chips were cut smaller by the roughing edge (Er), thus improving chip removal performance and preventing weld penetration.

[0086] The embodiments of the present invention have been described in detail above based on the accompanying drawings. However, these are only one implementation method. The present invention can be implemented with various changes and improvements based on the knowledge of those skilled in the art.

[0087] Explanation of reference numerals in the attached figures

[0088] 10: End mill, 12: Tool holder, 14: Cutting edge, 20, 30, 40: External cutting edge, 20a, 20b: External cutting edge (with convex and concave cutting edge), 24: Hard coating, A, B, C: Cutting edge (with convex and concave cutting edge), L: Cutting edge length, Er: Concave and concave cutting edge, α1, α2, α3: Helix angle (right-hand helix), β1, β2, β3: Helix angle (left-hand helix).

Claims

1. An end mill (10) having a plurality of peripheral cutting edges (20a, 20b, 20c; 30; 40), characterized in that, The helix angles (α1, α2, α3; β1, β2, β3) of the plurality of peripheral cutting edges (20a, 20b, 20c; 30; 40) are equal to each other, and, At least one of the plurality of peripheral cutting edges (20a, 20b, 20c; 30; 40) is a convex-concave cutting edge (20a, 20b; A, B, C), which is provided with a convex-concave edge (Er) composed of a notch or a roughing edge. The convex-concave cutting edge (Er) is only provided on a portion of the cutting edge length (L) of the convex-concave cutting edge (20a, 20b; A, B, C). The convex and concave cutting edges (20a, 20b; A, B, C) are any of the cutting edges (A), (B), and (C). The cutting edge (A) has the convex and concave cutting edges (Er) within a range of 5% to 65% of the cutting length (L) along the tool axis, extending from the end of the tool holder (12) towards the bottom cutting edge. The cutting edge (B) has the convex and concave cutting edges (Er) within a range of 5% to 65% of the cutting length (L) along the tool axis, extending from the end of the bottom cutting edge towards the tool holder (12). The cutting edge (C) has the convex and concave cutting edges (Er) within a range of 5% to 65% of the cutting length (L) along two directions from the center of the cutting length (L) along the tool axis. The plurality of peripheral cutting edges (20a, 20b, 20c; 30; 40) are any of the four types of cutting edges (A) to (D) consisting of the cutting edges (A) to (C) with concave and convex edges (20a, 20b; A, B, C) and the cutting edge (D) without the concave and convex edges (Er). They are configured to include two or more types in such a way that adjacent peripheral cutting edges (20a, 20b, 20c; 30; 40) are of different types. The helix angles (α1, α2, α3; β1, β2, β3) of the plurality of peripheral cutting edges (20a, 20b, 20c; 30; 40) are in the range of 0° to 5°.

2. The end mill according to claim 1, characterized in that, The surface of the cutting edge having the plurality of peripheral cutting edges (20a, 20b, 20c; 30; 40) is covered with a hard coating (24).

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