End mill

Abstract

The utility model provides an end mill which is configured to rotate around a central rotation axis, the end mill comprises a handle part and a cutting part, the cutting part extends forwards from the handle part along the central rotation axis, and the cutting part comprises a plurality of teeth separated by a plurality of chip grooves; the teeth extend axially forward along the cutting portion following a curved helical path about the central axis of rotation; the teeth extend from the head of the teeth to a first spiral transition part at a first spiral angle, extend from the first spiral transition part to a second spiral transition part at a second spiral angle, and then extend to the tail of the teeth at the first spiral angle; the second helical angle is larger than the first helical angle; and the first helical angle alpha is greater than or equal to 36 degrees and less than or equal to 39 degrees. The end mill has the effect of reducing chattering generated in the using process of the end mill.

Description

Technical Field

[0001] The utility model relates to the technical field of milling cutters, in particular to an end milling cutter. Background Art

[0002] CNC machine tool technology is a key pillar of the machining industry. Among the supporting equipment for CNC machine tools, CNC cutting tools are consumables and tools used to machine workpieces, decisively influencing efficiency, surface quality, and cost. In metal cutting, end mills are commonly used CNC cutting tools.

[0003] In related technologies, when an end mill is in use, resonance may occur between the end mill and the workpiece, machine tool, or tool system itself. The regenerative vibration of the end mill is an important factor affecting machining efficiency, tool life, and workpiece quality. Utility Model Content

[0004] In view of this, the present invention aims to provide an end milling cutter to reduce vibration generated during use of the end milling cutter.

[0005] In order to achieve the above-mentioned purpose, the technical solution of the utility model is achieved as follows:

[0006] An end mill configured for rotation about a central rotational axis, the end mill comprising a shank and a cutting portion extending forwardly from the shank along the central rotational axis, the cutting portion comprising a plurality of teeth separated from one another by a plurality of chip flutes;

[0007] The teeth extend forwardly along the cutting portion axis following a curved helical path about the central axis of rotation;

[0008] The tooth extends from its head to a first spiral transition portion at a first spiral angle, extends from the first spiral transition portion to a second spiral transition portion at a second spiral angle, and then extends to the tail of the tooth at the first spiral angle;

[0009] The second helix angle is greater than the first helix angle;

[0010] And the first helix angle satisfies 36°≤α≤39°.

[0011] Furthermore, the second helix angle is at least 2° and at most 5° greater than the first helix angle.

[0012] Furthermore, along the circumference of the cutting portion, the helix angles of two adjacent teeth change in opposite trends.

[0013] Furthermore, the number of teeth is an even number.

[0014] Furthermore, the cutting portion has four teeth.

[0015] Furthermore, the circumferential rake angle of the tooth is 4°.

[0016] Furthermore, the first clearance angle of the peripheral edge of the tooth is 8°.

[0017] Furthermore, the second clearance angle of the peripheral edge of the tooth is 16°.

[0018] Furthermore, the end tooth rake angle of the tooth is 14°.

[0019] Furthermore, the first clearance angle of the end tooth of the tooth is 8°, and / or the second clearance angle of the end tooth of the tooth is 16°.

[0020] Compared with the prior art, the present invention has the following advantages:

[0021] The end mill described in the utility model is configured with a first spiral transition portion and a second spiral transition portion so that the spiral angle of the tooth changes between the first spiral angle and the second spiral angle. When the tool is working, the self-vibration of the tool is used to offset the regenerative vibration of the tool, thereby reducing the vibration of the end mill during milling and improving the milling accuracy of the end mill.

[0022] By setting the helix angle changes of two adjacent teeth to show opposite trends, the end mill has greater damping in the direction of the central rotation axis, thereby making the size and time interval of the cutting force pulse different, achieving more effective suppression of the vibration generated by milling on the central rotation axis and optimizing the cutting performance of the end mill.

[0023] By setting the number of teeth to an even number, the cutting effect of the end mill is smoother and the end mill is suitable for materials with higher hardness.

[0024] Setting the tooth's circumferential rake angle to 4° improves the end mill's cutting sharpness while also ensuring its structural strength. Setting the tooth's primary clearance angle to 8° reduces friction between the end mill and the workpiece while also improving its structural strength. Setting the secondary clearance angle reduces the risk of the back bevel being higher than the cutting edge due to insufficient primary clearance angle during cutting.

[0025] Setting the end tooth rake angle to 14° reduces the cutting force required by the end mill and improves the end mill's tip strength. Setting the end tooth primary clearance angle to 8° reduces friction between the primary flank and the workpiece surface, reducing tool wear. The secondary clearance angle compensates for the situation where the primary clearance angle is insufficient, resulting in a higher bevel angle than the cutting edge. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] The accompanying drawings, which constitute part of the present invention, are intended to provide a further understanding of the present invention. The exemplary embodiments of the present invention and their descriptions are intended to explain the present invention and do not constitute an improper limitation of the present invention. In the accompanying drawings:

[0027] Figure 1 This is a schematic diagram of the overall structure of an embodiment of the utility model;

[0028] Figure 2 This is a diagram of the end teeth of an embodiment of the present utility model;

[0029] Figure 3 This is a circumferential expansion diagram of an embodiment of the present utility model;

[0030] Figure 4 A side view of an embodiment of the present utility model;

[0031] Figure 5 This is a cross-sectional view of the cutting portion of an embodiment of the present utility model;

[0032] Figure 6 This is a schematic diagram showing the front angle of the end teeth according to an embodiment of the present invention.

[0033] Description of reference numerals:

[0034] 1. Handle;

[0035] 2. Cutting portion; 201. Chip flute; 202. Tooth; 202a. Head; 202b. Tail; 2021. First spiral transition portion; 2022. Second spiral transition portion;

[0036] L, central rotation axis;

[0037] α, first helix angle; β, second helix angle; γ, circumferential blade rake angle; δ, circumferential blade first clearance angle; η, circumferential blade second clearance angle; θ, end tooth rake angle; λ, end tooth first clearance angle; μ, end tooth second clearance angle. DETAILED DESCRIPTION

[0038] It should be noted that, in the absence of conflict, the embodiments of the present invention and the features therein can be combined with each other.

[0039] In the description of this utility model, it should be noted that if terms such as "upper," "lower," "inner," and "outer" appear to indicate orientation or positional relationships, these are based on the orientation or positional relationships shown in the accompanying drawings and are intended solely to facilitate the description of this utility model and simplify the description. They do not indicate or imply that the device or component referred to must have a specific orientation, be constructed, or operate in a specific orientation. Therefore, they should not be construed as limitations on this utility model. Furthermore, if terms such as "first" and "second" appear, they are used solely for descriptive purposes and should not be construed as indicating or implying relative importance.

[0040] Furthermore, in the description of this utility model, unless otherwise explicitly defined, the terms "mounted," "connected," "connection," and "connector" should be interpreted broadly. For example, they can refer to fixed, removable, or integral connections; mechanical or electrical connections; direct or indirect connections through an intermediary; and internal communication between two components. Those skilled in the art will understand the specific meanings of these terms in this utility model based on specific circumstances.

[0041] The present invention will be described in detail below with reference to the accompanying drawings and in combination with embodiments.

[0042] This embodiment relates to an end mill to reduce vibration generated during use of the end mill.

[0043] In terms of overall structure, Figures 1 to 4 As shown, the end mill is configured to rotate around a central rotation axis L, and includes a shank 1 and a cutting portion 2, the cutting portion 2 extending forward from the shank 1 along the central rotation axis L, and the cutting portion 2 includes a plurality of teeth 202 separated from each other by a plurality of chip grooves 201; the teeth 202 extend axially forward along the cutting portion 2 following a curved spiral path around the central rotation axis L; the tooth 202 extends from its head 202a to a first spiral transition portion 2021 at a first spiral angle α, and extends from the first spiral transition portion 2021 to the second spiral transition portion 2022 at a second spiral angle β, and then extends to the tail 202b of the tooth 202 at the first spiral angle α; the second spiral angle β is greater than the first spiral angle α; and the first spiral angle α satisfies 36°≤α≤39°.

[0044] By setting the first spiral transition portion 2021 and the second spiral transition portion 2022, the spiral angle of the tooth 202 is changed between the first spiral angle α and the second spiral angle β. When the tool is working, the self-vibration of the tool offsets the regenerated vibration of the tool, thereby reducing the vibration of the end mill during milling and improving the milling accuracy of the end mill.

[0045] Based on the above overall introduction, Figure 3 and Figure 4As shown, in this embodiment, the cutting portion 2 is divided into five equal segments along the central rotation axis L. As an optional method, the five segments are of equal length, that is, the first spiral transition portion 2021 and the second spiral transition portion 2022 are of equal length. The first spiral transition portion 2021 is located on the side near the head 202a of the tooth 202. The provision of the first spiral transition portion 2021 and the second spiral transition portion 2022 can achieve a smooth transition between the first helix angle α and the second helix angle β of the tooth 202. Specifically, 36°≤α≤39°. For example, the first helix angle α can be 36°, 38°, or 39°, with the preferred first helix angle α being 38°.

[0046] On the basis that the second helix angle β is greater than the first helix angle α, as Figure 3 and Figure 4 As shown, in order to further improve the stability of the end mill, the second helix angle β is at least 2° and at most 5° larger than the first helix angle α, that is, 38°≤β≤44°, for example, it can be 39°, 41°, 43° or 44°. Preferably, on the basis of satisfying that the first helix angle α is greater than the second helix angle β, the preferred second helix angle β is 41°.

[0047] To further optimize the cutting performance of the end mill, the helix angles of two adjacent teeth 202 change in opposite directions along the circumference of the cutting portion 2. That is, assuming a tooth 202 extends from its head 202a to the first helical transition portion 2021 at a first helical angle α, then extends from the first helical transition portion 2021 to the second helical transition portion 2022 at a second helical angle β, and then extends to the tail 202b of the tooth 202 at the first helical angle α, then the two adjacent teeth 202 on either side of the tooth 202 extend from their head 202a to the first helical transition portion 2021 at the second helical angle β, then extend from the first helical transition portion 2021 to the second helical transition portion 2022 at the first helical angle α, and then extend to the tail 202b of the tooth 202 at the second helical angle β.

[0048] By setting the helix angle changes of two adjacent teeth 202 to show opposite trends, the end mill has greater damping in the direction of the central rotation axis L, thereby making the size and time interval of the cutting force pulse different, achieving more effective suppression of the vibration generated by milling on the central rotation axis L, and optimizing the cutting performance of the end mill.

[0049] In order to make the end mill suitable for workpieces with higher hardness, the number of teeth 202 is an even number. Specifically, in this embodiment, the cutting portion 2 preferably has four teeth 202. By setting the number of teeth 202 to an even number, the end mill has a smoother cutting effect and is suitable for materials with higher hardness.

[0050] In order to ensure the structural strength of the end mill while meeting the cutting sharpness of the end mill, such as Figures 1 to 5 As shown, the circumferential rake angle γ of tooth 202 is 4°, the first clearance angle δ of tooth 202 is 8°, and the second clearance angle η of tooth 202 is 16°. By setting the circumferential rake angle γ of tooth 202 to 4°, the end mill has better cutting sharpness while also ensuring the structural strength of the end mill. Furthermore, by setting the first clearance angle δ of tooth 202 to 8°, the friction between the end mill and the workpiece is reduced while also improving the structural strength of the end mill. Setting the second clearance angle η reduces the possibility that the back bevel angle is higher than the cutting edge due to the insufficient first clearance angle δ during cutting.

[0051] The circumferential rake angle γ is the angle between the rake face of the peripheral cutting edge of an end mill and its base surface. The size of the circumferential rake angle γ is directly related to the cutting performance and life of the end mill. The circumferential first clearance angle δ is the intersection of the flute rake face and the first clearance angle surface on the peripheral cutting edge of the end mill. It is used to cut off iron chips and meet workpiece size requirements.

[0052] At the same time, if Figures 1 to 6 As shown, the end tooth rake angle θ of tooth 202 is 14°, the end tooth first clearance angle λ of tooth 202 is 8°, and the end tooth second clearance angle μ of tooth 202 is 16°. Setting the end tooth rake angle θ to 14° reduces the cutting force required by the end mill during use, while also improving the tip strength of the end mill. Setting the end tooth first clearance angle λ to 8° reduces friction between the main back cutting edge and the workpiece machining surface, reducing tool wear. The end tooth second clearance angle μ is used to compensate for the situation where the end tooth first clearance angle λ is insufficient, resulting in a back bevel angle that is higher than the cutting edge.

[0053] The end tooth rake angle θ, defined as the angle between the front end of the end mill's cutting edge and the normal to the end mill's body, is a crucial parameter in milling cutter design. The end tooth first clearance angle λ, typically measured in an orthogonal plane, is the angle between the end tooth and the workpiece's contact surface. The end tooth second clearance angle μ is designed to prevent the first clearance angle of the end tooth 202 from causing the back bevel to be higher than the cutting edge during cutting.

[0054] The end mill described in the embodiment of the present application sets a first spiral transition portion 2021 and a second spiral transition portion 2022, so that the spiral angle of the tooth 202 changes between a first spiral angle α and a second spiral angle β. When the tool is working, the tool's own vibration cancels out the regenerated vibrations of the tool, thereby reducing the vibration of the end mill during milling and improving the milling accuracy of the end mill.

[0055] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent replacements, improvements, etc. made within the spirit and principles of the present invention should be included in the scope of protection of the present invention.

Claims

1. An end mill configured to rotate about a central rotation axis (L), the end mill comprising a shank (1) and a cutting portion (2), the cutting portion (2) extending forward from the shank (1) along the central rotation axis (L), and the cutting portion (2) comprising a plurality of teeth (202) separated from each other by a plurality of chip flutes (201), characterized in that: The teeth (202) extend axially forward along the cutting portion (2) following a curved helical path about the central rotation axis (L); The tooth (202) extends from its head (202a) to a first spiral transition portion (2021) at a first spiral angle (α), and extends from the first spiral transition portion (2021) to a second spiral transition portion (2022) at a second spiral angle (β), and then extends to a tail portion (202b) of the tooth (202) at the first spiral angle (α); The second helix angle (β) is greater than the first helix angle (α); And the first helix angle (α) satisfies 36°≤α≤39°.

2. The end mill according to claim 1, wherein: The second helix angle (β) is greater than the first helix angle (α) by at least 2° and at most 5°.

3. The end mill according to claim 1, wherein: Along the circumference of the cutting portion (2), the helical angles of two adjacent teeth (202) change in opposite trends.

4. The end mill according to claim 1, wherein: The number of the teeth (202) is an even number.

5. The end mill according to claim 4, characterized in that: The cutting portion (2) has four teeth (202).

6. The end mill according to claim 1, wherein: The circumferential rake angle (γ) of the tooth (202) is 4°.

7. The end mill according to claim 1, wherein: The first clearance angle (δ) of the peripheral edge of the tooth (202) is 8°.

8. The end mill according to claim 1, wherein: The second clearance angle (η) of the peripheral edge of the tooth (202) is 16°.

9. The end mill according to claim 1, wherein: The end tooth rake angle (θ) of the tooth (202) is 14°.

10. The end mill according to claim 1, wherein: The first clearance angle (λ) of the end teeth of the tooth (202) is 8°, and / or the second clearance angle (μ) of the end teeth of the tooth (202) is 16°.

Images