Keyhole machining reamer

Abstract

The application relates to a keyhole machining reamer, which is applied to the field of keyhole machining and comprises a shank, one end of the shank is provided with a tool transition cone, the end, away from the shank, of the tool transition cone is sequentially provided with a cutting part and a blade part avoiding part, the cutting part is provided with a plurality of cutting edges, and the chamfered part of the plurality of cutting edges is provided with a circular-arc blade. The application has the technical effect that the circular-arc blade reduces stress concentration points, can better disperse the intense cutting force and impact force generated in the machining process, greatly reduces the risk of tool tip collapse, thereby significantly improves the durability and service life of the reamer, simultaneously reduces the phenomenon of blade collapse, reduces the frequency of reamer replacement during production, thereby improves the keyhole machining quality and reduces the waste rate.

Description

Technical Field

[0001] This application relates to the field of button hole processing technology, and in particular to a button hole processing reamer. Background Technology

[0002] The button holes on the side of a mobile phone are channels connecting the inside and outside of the phone and are crucial to the phone's waterproof and dustproof performance. Therefore, the dimensional accuracy, surface roughness, and cylindricity of the button holes must meet high standards, and they are generally machined by reaming.

[0003] When machining the button holes of a mobile phone casing made of titanium alloy using a reamer, the reamer has a cutting part on its tip, and the chamfer at the cutting end of the cutting part has a sharp point.

[0004] During the machining of keyholes, the aforementioned reamer is prone to chipping due to stress concentration at the tip under the intense friction and impact of the titanium alloy. Once chipped, it will leave obvious annular marks on the hole wall, resulting in scrapped parts and affecting production efficiency and production costs. Summary of the Invention

[0005] To address the problem in related technologies where reamers, during the machining of keyholes, suffer from stress concentration at the tip due to intense friction and impact on titanium alloys, easily causing the tool tip to chip, leaving obvious annular marks on the hole wall and resulting in scrapped parts, thus affecting production efficiency and costs, this application provides a reamer for keyhole machining, employing the following technical solution: It includes a tool holder, one end of which is provided with a tool transition cone. The end of the tool transition cone opposite to the tool holder is sequentially provided with a cutting section and a cutting edge avoidance section. The cutting section is provided with several cutting edges, and the chamfered edges of these cutting edges are provided with rounded edges.

[0006] In one specific implementation, the length of the arc-shaped blade ranges from 0.15 to 0.25 mm, and the radius of the arc-shaped blade ranges from 9 to 11 mm.

[0007] In one specific implementation, the end of the arc-shaped blade facing the handle is provided with a straight blade, the length of which ranges from 0.45 to 0.55 mm.

[0008] In one specific implementation scheme, the end of the straight blade facing away from the arc blade is provided with an inverted conical blade, and the taper value of the inverted conical blade is 0.12 / 100mm.

[0009] In one specific implementation, the cutting part and the edge clearance part are provided with a plurality of spirally extending chip removal grooves along the outer peripheral wall, and the spiral angle between the plurality of chip removal grooves and the axis of the cutting part and the edge clearance part is in the range of 18~22°.

[0010] In one specific implementation, a peripheral blade is provided between two adjacent chip removal grooves, and a forming blade is provided on the peripheral blade.

[0011] In one specific implementation scheme, the cutting part is provided with a plurality of chip-receiving grooves, and the plurality of chip-receiving grooves are respectively connected to a plurality of chip-removing grooves.

[0012] In one specific implementation, the cutting edge is provided with a rake angle, the rake angle being in the range of 8~11°.

[0013] In one specific implementation, the cutting edge is provided with a first clearance angle, a second clearance angle and a third clearance angle in sequence, wherein the first clearance angle has an angle range of 11~13°, the second clearance angle has an angle range of 22~26°, and the third clearance angle has an angle range of 42~47°.

[0014] In one specific implementation, the tool holder, tool transition cone, and cutting section are made of a cermet material.

[0015] In summary, this application offers the following beneficial technical effects: It transforms the easily chipped "sharp point" into a smoothly transitioning "circular arc edge," reducing stress concentration points. The circular arc edge better disperses the intense cutting and impact forces generated during machining, significantly reducing the risk of tip chipping, thereby significantly improving the durability and service life of the reamer. Simultaneously, it reduces the occurrence of chipping, decreasing the frequency of downtime for reamer replacements, thus improving the machining quality of keyholes and reducing the scrap rate. Attached Figure Description

[0016] Figure 1 This is a schematic diagram of the overall structure of an embodiment of this application.

[0017] Figure 2 yes Figure 1 Enlarged diagram of point A in the middle.

[0018] Figure 3 This is a schematic diagram illustrating the straight blade in the embodiments of this application.

[0019] Figure 4 This is a schematic diagram illustrating the structure of the chip removal groove in the embodiments of this application.

[0020] Figure 5 This is a structural schematic diagram used to illustrate the front corner in the embodiments of this application.

[0021] Reference numerals: 1. Tool holder; 2. Tool transition cone; 3. Cutting part; 4. Cutting edge; 5. Straight edge; 6. Reverse conical edge; 7. Chip groove; 8. Circumferential edge; 9. Forming edge; 10. Chip groove; 11. Circular arc edge; 12. Edge clearance part. Detailed Implementation

[0022] The following is in conjunction with the appendix Figure 1-5 This application will be described in further detail.

[0023] This application discloses a reamer for machining button holes.

[0024] Reference Figure 1 , Figure 2 and Figure 3 The reamer for keyhole machining includes a cylindrical tool holder 1 clamped at the machining end of a machine tool. A tool transition cone 2 is fixedly connected to one end of the tool holder 1. Considering the machining characteristics of titanium alloy, which has a low elastic modulus, the clamping deformation and stress deformation of the part during machining are large, and titanium alloy is prone to chip adhesion during cutting. The tool holder 1, tool transition cone 2, and cutting section 3 are made of cermet material. Cermet material has advantages such as high hardness, wear resistance, high temperature resistance, and resistance to chip adhesion, improving the surface finish of the machined surface or hole wall, while also saving on reamer coating processes. The cutting section 3 and a cutting edge avoidance section 12 are sequentially arranged at the end of the tool transition cone 2 away from the tool holder 1. The cutting section 3 is provided with several cutting edges 4. In this embodiment, three evenly distributed cutting edges 4 are used as an example. The cutting edges 4 adopt a three-long-tooth design and an odd number of cutting edges, which can reduce vibration during tool machining and enhance the stability of the reamer during machining.

[0025] Reference Figure 1 , Figure 2 and Figure 3 A circular arc edge 11 is provided at the chamfer of several cutting edges 4. The length of the circular arc edge 11 ranges from 0.15 to 0.25 mm, preferably 0.2 mm; and the radius R of the circular arc edge 11 ranges from 9 to 11 mm, preferably 10 mm. In this embodiment, the vertical drop between the end of the circular arc edge 11 facing the tool holder 1 and the end of the chamfer of the cutting edge 4 is 0.006 ± 0.003 mm. Therefore, the easily chipped "sharp point" is improved into a smoothly transitioning "circular arc edge 11", reducing stress concentration points. The circular arc edge 11 can better disperse the severe cutting force and impact force generated during the machining of titanium alloys, greatly reducing the risk of tool tip chipping, thereby significantly improving the durability and service life of the reamer, while reducing the occurrence of chipping, reducing the frequency of downtime for reamer replacement during production, thereby improving the machining quality of keyholes and reducing the scrap rate.

[0026] Reference Figure 1 , Figure 2 and Figure 3A straight cutting edge 5 is provided at the end of the arc-shaped cutting edge 11 facing the tool holder 1. The length of the straight cutting edge 5 ranges from 0.45 to 0.55 mm, preferably 0.5 mm. The straight cutting edge 5 ensures the correct hole diameter and reduces the problem of the hole diameter being too large. A tapered cutting edge 6 is provided at the end of the straight cutting edge 5 away from the arc-shaped cutting edge 11. The taper value of the tapered cutting edge 6 is 0.12 / 100 mm, that is, for a length of 100 mm along the X-axis, the diameter is reduced by 0.12 mm in the Y-axis direction, which is approximately equal to 0.0344 degrees according to the arctangent function. When the cutting part 3 enters the workpiece, the tapered cutting edge 6 can reduce the friction between the cutting rear end and the workpiece, thereby improving the quality of the machined hole.

[0027] Reference Figure 1 , Figure 2 and Figure 4 The cutting section 3 and the edge clearance section 12 are provided with a plurality of spirally extending chip removal grooves 7 along their outer peripheral walls. A peripheral cutting edge 8 is provided between two adjacent chip removal grooves 7. The peripheral cutting edge 8 has a forming edge 9 provided according to the size and shape of the key hole. During machining, the peripheral cutting edge 8 contacts the hole wall, providing support and guidance for the reamer, effectively reducing reamer wobbling or deflection within the drilled hole, and greatly enhancing the stability of the cutting process. The helix angle γ between the plurality of chip removal grooves 7 and the axes of the cutting section 3 and the edge clearance section 12 ranges from 18° to 22°, preferably 20°. The cutting section 3 is provided with a plurality of chip receiving grooves 10, which communicate with the plurality of chip removal grooves 7. In this embodiment, the number of chip receiving grooves 10 is set to three. During the cutting process, the chip groove 10 provides space to temporarily accommodate the chips, preventing them from clogging between the machined hole wall and the tool. Subsequently, the chips are discharged along the chip removal groove 7, which guides the chips and reduces the occurrence of hole wall damage due to poor chip removal.

[0028] Reference Figure 4 and Figure 5 The cutting edge 4 is provided with a rake angle α, which ranges from 8 to 11°, preferably 10°. The cutting edge 4 is sequentially provided with a first clearance angle β1, a second clearance angle β2, and a third clearance angle β3. The first clearance angle β1 ranges from 11 to 13°, preferably 12°; the second clearance angle β2 ranges from 22 to 26°, preferably 25°; and the third clearance angle β3 ranges from 42 to 47°, preferably 45°. The rake angle α, the first clearance angle β1, the second clearance angle β2, and the third clearance angle β3 ensure that the tool has cutting force while preventing the tool from becoming too sharp, thus reducing the occurrence of chipping and circular marks on the machined hole wall during cutting.

[0029] Furthermore, in this embodiment, the reamer used for keyhole machining requires shot peening to remove surface dirt, oxide layers, and other substances. This process also improves the surface quality and wear resistance of the tool, ensuring the appearance requirements of the machined product. In this embodiment, the tool transition cone 2 has a small core thickness, specifically 38%D, where D is φ2.25mm at the maximum cutting diameter of the cutting section 3. This further increases the chip removal space of the tool, reducing the possibility of chip accumulation scratching the hole wall.

[0030] The implementation principle of this application embodiment is as follows: the easily chipped "sharp point" is improved into a smoothly transitioned "circular arc edge 11", reducing stress concentration points. The circular arc edge 11 can better disperse the severe cutting force and impact force generated during the machining of titanium alloys, greatly reducing the risk of tool tip chipping, thereby significantly improving the durability and service life of the reamer. At the same time, it reduces the occurrence of chipping and circular marks on the hole wall, reducing the frequency of downtime for reamer replacement during production, thereby improving the machining quality of keyholes and reducing the scrap rate.

[0031] This specific embodiment is merely an explanation of the present invention and is not intended to limit the invention. After reading this specification, those skilled in the art can make modifications to this embodiment without contributing any inventive step, but such modifications are protected by patent law as long as they are within the scope of the claims of the present invention.

Claims

1. A reamer for machining button holes, characterized in that: The tool includes a handle (1), one end of which is provided with a tool transition cone (2). The end of the tool transition cone (2) away from the handle (1) is provided with a cutting part (3) and a cutting edge avoidance part (12) in sequence. The cutting part (3) is provided with a plurality of cutting edges (4), and the chamfer of the plurality of cutting edges (4) is provided with a rounded edge (11).

2. The reamer for keyhole machining according to claim 1, characterized in that: The length of the arc blade (11) ranges from 0.15 to 0.25 mm, and the radius of the arc blade (11) ranges from 9 to 11 mm.

3. The reamer for keyhole machining according to claim 1, characterized in that: The arc-shaped blade (11) has a straight blade (5) at one end facing the handle (1), and the length of the straight blade (5) is in the range of 0.45~0.55mm.

4. The reamer for keyhole machining according to claim 3, characterized in that: The straight blade (5) is provided with an inverted conical blade (6) at one end away from the arc blade (11), and the taper value of the inverted conical blade (6) is 0.12 / 100mm.

5. The reamer for keyhole machining according to claim 1, characterized in that: The cutting part (3) and the edge clearance part (12) are provided with a plurality of spirally extending chip removal grooves (7) along the outer peripheral wall, and the spiral angle between the plurality of chip removal grooves (7) and the axis of the cutting part (3) and the edge clearance part (12) is in the range of 18~22°.

6. The reamer for keyhole machining according to claim 5, characterized in that: A peripheral blade (8) is provided between two adjacent chip removal grooves (7), and a forming blade (9) is provided on the peripheral blade (8).

7. The reamer for keyhole machining according to claim 5, characterized in that: The cutting part (3) is provided with a plurality of chip grooves (10), and the plurality of chip grooves (10) are respectively connected to a plurality of chip discharge grooves (7).

8. The reamer for keyhole machining according to claim 1, characterized in that: The cutting edge (4) is provided with a rake angle, the rake angle range being 8~11°.

9. The reamer for keyhole machining according to claim 1, characterized in that: The cutting edge (4) is provided with a first rear angle, a second rear angle and a third rear angle in sequence. The first rear angle has an angle range of 11~13°, the second rear angle has an angle range of 22~26° and the third rear angle has an angle range of 42~47°.

10. The reamer for keyhole machining according to claim 1, characterized in that: The tool holder (1), tool transition cone (2), and cutting section (3) are made of cermet material.

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