A reamer with controllable roughness

Abstract

The utility model belongs to processing tool technical field, concretely relates to a controllable roughness's reamer, and it includes: tool body, handle and cutting blade, forms the cutting edge and the destructive blade on cutting blade, cutting edge is located in the front of destructive blade, cutting edge extends from tool body front end to the outer circumferential surface of tool body and is used for cutting processing to deep hole hole wall, destructive blade sets up on the outer circumferential surface of tool body, and protrudes on cutting edge in tool body radial, and the protruding height is H, and destructive blade is used for processing the oil storage structure of predetermined depth on deep hole hole wall surface, and the predetermined depth of oil storage structure is H. The utility model discloses through setting double blade opening cutting blade, and the hole wall after cutting through cutting edge has the first roughness, and the hole wall after cutting through destructive blade has the second roughness, and cutting edge and destructive blade cooperate in single feed process, and realize the synchronous processing of two different roughness surfaces in the deep hole inner wall of same hole diameter through a reamer.

Description

Technical Field

[0001] This utility model relates to the field of machining tool technology, and in particular to a reamer with controllable roughness. Background Technology

[0002] In the field of precision machining of deep holes in aluminum piston sleeves, the reamer, as the core cutting tool directly involved in the cutting process, has structural characteristics that are directly related to the machining effect. In existing technologies, for machining scenarios with a length-to-diameter ratio (length / diameter) < 3, due to the high rigidity of the tool, reamers with boring edges and back cone structures are typically used. By adjusting the corner radius R and the feed per edge f, the maximum depth Rmax of the surface microstructure can be controlled to meet the basic roughness requirements. The specific formula for calculating Rmax is as follows: However, when machining deep holes with a length-to-diameter ratio greater than 3, existing reamers suffer from a significant decrease in rigidity due to the increased length-to-diameter ratio, which can easily cause vibration and make it difficult to guarantee the surface quality and dimensional accuracy of the inner hole.

[0003] To address the machining challenges of diameter ratios greater than 3, the industry often employs a combination of processes such as boring, honing, and roller burnishing. However, this approach suffers from drawbacks including complex procedures, low efficiency, and high costs. Particularly problematic is the need to achieve two distinct surface roughnesses (e.g., different Rmax values) in deep hole machining of aluminum piston sleeves. Current technologies require changing cutting tools with different fillet radii and repeatedly adjusting the machine tool feed rate to achieve this. This operational mode not only increases the time spent on auxiliary processes such as tool changes, tool setting, and parameter adjustments but also leads to poor machining consistency due to frequent manual intervention, further increasing production costs and cycle time. Utility Model Content

[0004] The technical problem to be solved by this utility model is: in order to solve the technical problems of insufficient rigidity, easy tool vibration, and need for multiple tool changes when machining deep holes with a length-to-diameter ratio > 3, the existing reamers provide a reamer with controllable roughness to realize the synchronous machining of two surfaces with different roughnesses on the inner wall of the deep hole.

[0005] The technical solution adopted by this utility model to solve its technical problem is: a reamer with controllable roughness for machining deep holes, comprising: a cutter body, a shank disposed at the rear end of the cutter body, and a cutting blade disposed at the front end of the cutter body. The cutting blade has a cutting edge and a breaking edge formed thereon. The cutting edge is located in front of the breaking edge and is closer to the shank than the cutting edge. The cutting edge extends from the front end of the cutter body to the outer peripheral surface of the cutter body for cutting the wall of the deep hole. The breaking edge is disposed on the outer peripheral surface of the cutter body and protrudes radially beyond the cutting edge of the cutter body by a protrusion height of H. The breaking edge is used to machine an oil storage structure of a predetermined depth on the surface of the deep hole wall, the predetermined depth of the oil storage structure being H.

[0006] Furthermore, the tool body is provided with a chip removal groove, which extends axially from the front end of the tool body towards the tool holder, and the cutting insert is embedded in the chip removal groove. The chip removal groove is designed to guide the chips out smoothly, preventing chips from accumulating inside the deep hole or wrapping around the tool, preventing chips from scratching the surface of the deep hole or impacting the tool, and improving machining accuracy and surface quality.

[0007] Furthermore, the number of cutting blades is multiple, and the multiple cutting blades are arranged in a ring array around the outer circumference of the cutter body. Using multiple cutting blades improves cutting efficiency and cutting uniformity.

[0008] Furthermore, the reamer is provided with a central water outlet hole, which extends from the front end face of the cutter body through the cutter body and the shank to the rear end face of the shank. By providing a central water outlet hole, cutting fluid is sprayed onto the cutting position during the cutting process. The cutting fluid impacts the chips, forcibly removing them and preventing the chips from scratching the surface of the deep hole or impacting the cutting tool.

[0009] Further, the cutting insert includes an insert body, a cutting edge formed at the front of the insert body, and a breaking edge formed at the middle of the insert body. The insert body is mounted on the front end of the tool body. The cutting edge includes a second arc edge, a conical edge, and a first arc edge arranged sequentially along the direction away from the tool holder. The second arc edge, the conical edge, and the first arc edge are all formed on the outer side wall of the insert body. The conical edge connects the first arc edge and the second arc edge and is inclined away from the axis of the tool body. The radius of the first arc edge is R1, the radius of the second arc edge is R2, and the included angle between the conical edge and the axis of the tool body is α1.

[0010] Furthermore, the cutting edge also includes an end edge formed on the front end face of the blade body. The end edge is tangentially connected to the first arc edge. The width γ1 of the end edge is 0.3±0.05mm, the length L1 of the end edge is 3.5±0.05mm, and the end edge is provided with an end edge back angle β1, the angle of which is 7°±1°.

[0011] Furthermore, the cutting edge also includes a first circumferential cutting edge formed on the outer wall of the blade body. The first circumferential cutting edge is located between the second arc-shaped cutting edge and the breaking edge. The first circumferential cutting edge is tangentially connected to the second arc-shaped cutting edge. The width γ2 of the first circumferential cutting edge is 0.3±0.05mm, the length L2 of the first circumferential cutting edge is 1.1±0.05mm, and the first circumferential cutting edge is provided with a first cutting edge clearance angle β2, the angle of the first cutting edge clearance angle β2 is 13°±2°.

[0012] Furthermore, the breaking edge includes a second circumferential cutting edge formed on the outer wall of the blade body. The gap between the second circumferential cutting edge and the first circumferential cutting edge in the radial direction of the blade body is H. The width γ3 of the second circumferential cutting edge is 0.3±0.02mm, the length L3 of the second circumferential cutting edge is 0.1±0.02mm, and the second circumferential cutting edge is provided with a second cutting edge back angle β3, the angle of the second cutting edge back angle β3 is 5°±2°.

[0013] Furthermore, the second circumferential cutting edge includes a rounded corner cutting edge and a flat cutting edge, the rounded corner cutting edge being tangent to the flat cutting edge, the radius of the rounded corner cutting edge being R3, and the gap formed between the flat cutting edge and the first circumferential cutting edge in the radial direction of the blade body being H, the range of H being 0.002 to 0.006 mm.

[0014] Furthermore, the blade body and the blade holder are coaxially arranged and integrally formed, and the cutting blade is welded to the blade body.

[0015] Compared with the prior art, the beneficial effects of this utility model are: (1) The reamer of this utility model is equipped with a double-edged cutting blade structure with a cutting edge and a breaking edge. The cutting edge is used to cut the wall of the deep hole and undertakes the main cutting function. The hole wall after being cut by the cutting edge has a first roughness. The breaking edge is located behind the cutting edge and protrudes from the cutting edge in the radial direction of the tool body. It can perform micro-cutting on the hole wall surface cut by the cutting edge to destroy the smoothness of the deep hole wall. The hole wall after being cut by the breaking edge has a second roughness. The cutting edge and the breaking edge work together in a single feed process. The reamer can achieve synchronous processing of two different roughness surfaces on the inner wall of the deep hole of the same diameter, avoiding the clamping error caused by multiple tool changes and adjustments in the traditional process. (2) The breaking edge of this utility model protrudes from the cutting edge in the radial direction of the blade body, and the protrusion height is H. That is to say, the surface cut by the breaking edge is rougher than the surface cut by the cutting edge. The protrusion height H directly constitutes the second roughness Rmax value. That is, the surface after being cut by the breaking edge will form an oil storage structure similar to a thread shape. This oil storage structure can hold lubricating oil. The maximum depth of this oil storage structure is H. (3) The cutting edge of this utility model adopts a composite cutting edge design, which is composed of a second circular arc edge, a conical edge and a first circular arc edge connected in sequence. This structure completes the 30° conical surface forming of the bottom of the deep hole and the double-segment R0.4mm rounded corner transition simultaneously in one feed process, transforming the traditional step-by-step processing into continuous processing, eliminating the cumulative dimensional error caused by process connection, and ensuring the accuracy of the feature position and shape of the bottom of the deep hole. Attached Figure Description

[0016] The present invention will be further described below with reference to the accompanying drawings and embodiments.

[0017] Figure 1 This is a schematic diagram of the structure of a reamer with controllable roughness according to the present invention; Figure 2 for Figure 1 Enlarged schematic diagram of a local structure at point A; Figure 3 for Figure 1 The main view; Figure 4 for Figure 3 Schematic diagram of the cross-sectional structure of the middle BB section; Figure 5 for Figure 3 Schematic diagram of the cross-sectional structure of the middle CC section; Figure 6 for Figure 3 Enlarged schematic diagram of the local structure at point D; Figure 7 for Figure 5 Enlarged schematic diagram of the local structure at point E in the middle; Figure 8 for Figure 5 Enlarged schematic diagram of the local structure at point F; Figure 9 for Figure 3 A bottom view.

[0018] In the diagram: 1. Tool body; 101. Chip removal groove; 102. Beveled structure; 2. Cutting edge; 201. Second arc edge; 202. Conical edge; 203. First arc edge; 204. End edge; 205. First circumferential cutting edge; 3. Breaking edge; 301. Second circumferential cutting edge; 3011. Rounded corner edge; 3012. Flat edge; 302. Back cone edge; 4. Tool holder; 5. Cutting insert; 6. Center water outlet; 7. Insert body. Detailed Implementation

[0019] The present invention will now be described in further detail with reference to the accompanying drawings. These drawings are simplified schematic diagrams, illustrating only the basic structure of the present invention, and therefore only show the components relevant to the present invention.

[0020] In the description of this utility model, it should be understood that the terms "center," "longitudinal," "transverse," "length," "width," "thickness," "upper," "lower," "front," "rear," "left," "right," "vertical," "horizontal," "top," "bottom," "inner," "outer," "clockwise," "counterclockwise," "axial," "radial," and "circumferential," etc., indicating the orientation or positional relationship shown in the accompanying drawings, are only for the convenience of describing this utility model and simplifying the description, and do 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 a limitation of this utility model. Furthermore, features defined with "first" or "second" may explicitly or implicitly include one or more of that feature. In the description of this utility model, unless otherwise stated, "a plurality of" means two or more.

[0021] In the description of this utility model, it should be noted that, unless otherwise explicitly specified and limited, the terms "installation," "connection," and "joining" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; and they can refer to the internal connection of two components. Those skilled in the art can understand the specific meaning of the above terms in this utility model based on the specific circumstances.

[0022] like Figures 1 to 9 The diagram shows a preferred embodiment of the present invention. This embodiment provides a reamer with controllable roughness, comprising: a cutter body 1, a shank 4 disposed at the rear end of the cutter body 1, and a cutting blade 5 disposed at the front end of the cutter body 1. The cutting blade 5 has a cutting edge 2 and a breaking edge 3. The cutting edge 2 is located in front of the breaking edge 3, and the breaking edge 3 is closer to the shank 4 than the cutting edge 2. The cutting edge 2 extends from the front end of the cutter body 1 to the outer peripheral surface of the cutter body 1 for cutting the wall of a deep hole. The breaking edge 3 is disposed on the outer peripheral surface of the cutter body 1 and protrudes radially beyond the cutting edge 2, with a protrusion height of H. The breaking edge 3 is used to process an oil storage structure of a predetermined depth on the surface of the deep hole wall, the predetermined depth of which is H.

[0023] In a preferred embodiment, there are multiple cutting blades 5 arranged in a ring array around the outer circumference of the cutter body 1. Using multiple cutting blades 5 improves cutting efficiency and cutting uniformity.

[0024] Specifically, the number of cutting blades 5 is at least four, and in this embodiment, the number of cutting blades 5 is six. The more cutting blades 5 there are, the greater the feed rate can be set during cutting, thereby improving cutting efficiency.

[0025] In a preferred embodiment, the cutter body 1 is provided with six chip removal grooves 101, which are arranged in a ring array around the outer circumference of the cutter body 1. Each chip removal groove 101 extends axially from the front end of the cutter body 1 toward the tool holder 4, and the cutting insert 5 is embedded in the chip removal groove 101. The chip removal grooves 101 are designed to guide the chips to be discharged smoothly, avoiding the accumulation of chips inside the deep hole or wrapping around the tool, preventing the chips from scratching the surface of the deep hole or impacting the tool, and improving machining accuracy and surface quality.

[0026] In a preferred embodiment, each chip groove 101 has a beveled structure 102 at its bottom, and each beveled structure 102 is located close to a cutting blade 5. The beveled structure 102 extends from the bottom of the chip groove 101 to the front end face of the blade body 1. By setting the beveled structure 102, blade interference can be avoided.

[0027] In a preferred embodiment, the cutter body 1 and the shank 4 are coaxially arranged and integrally formed, and the cutting blade 5 is welded to the cutter body 1. Specifically, both the cutter body 1 and the shank 4 are made of cemented carbide, and with the addition of multiple cutting blades 5 arranged in a ring array, the overall rigidity of the reamer can be improved, providing a deep hole vibration resistance effect.

[0028] In a preferred embodiment, the reamer is provided with a central water outlet 6, which extends from the front end face of the cutter body 1 through the cutter body 1 and the shank 4 to the rear end face of the shank 4. By providing the central water outlet 6, cutting fluid is sprayed onto the cutting position during the cutting process. The cutting fluid impacts the chips, forcibly removing them and preventing the chips from scratching the surface of the deep hole or impacting the cutting tool.

[0029] In a preferred embodiment, the cutting insert 5 includes an insert body 7, a cutting edge 2 formed at the front of the insert body 7, and a breaking edge 3 formed at the middle of the insert body 7. The insert body 7 is mounted on the front end of the tool body 1. The cutting edge 2 includes a second arc edge 201, a conical edge 202, and a first arc edge 203 arranged sequentially in a direction away from the tool holder 4. The second arc edge 201, the conical edge 202, and the first arc edge 203 are all formed on the outer side wall of the insert body 7. The conical edge 202 connects the first arc edge 203 and the second arc edge 201 and is inclined in a direction away from the axis of the tool body 1. The radius of the first arc edge 203 is R1, the radius of the second arc edge 201 is R2, and the included angle between the conical edge 202 and the axis of the tool body 1 is α1.

[0030] Specifically, the radius R1 of the first arc-shaped cutting edge 203 matches the radius of a fillet at the bottom of the deep hole to be machined, the radius R2 of the second arc-shaped cutting edge 201 matches the radius of another fillet at the bottom of the deep hole to be machined, and the included angle α1 formed between the conical cutting edge 202 and the axis of the tool body 1 matches the inclination angle of the conical surface at the bottom of the deep hole.

[0031] In this embodiment, R1 ranges from 0.4±0.05mm, R2 ranges from 0.4±0.05mm, the included angle α1 ranges from 30°±2°, the projected length L5 of the conical cutting edge 202 on the axis of the tool body 1 is 0.2±0.03mm, and the overall projected length L6 of the second arc cutting edge 201, the conical cutting edge 202, and the first arc cutting edge 203 on the axis of the tool body 1 is 0.6±0.03mm. This cutting insert 5 structure design simultaneously completes the 30° conical surface forming of the bottom of the deep hole and the double-segment R0.4mm rounded corner transition during one feed, transforming the traditional step-by-step machining into continuous machining, eliminating the cumulative dimensional errors caused by process connection, and ensuring the positional and shape accuracy of the features at the bottom of the deep hole.

[0032] In a preferred embodiment, the cutting edge 2 further includes an end edge 204 formed on the front end face of the blade body 7. The end edge 204 is tangentially connected to the first arc edge 203. The width γ1 of the end edge 204 is 0.3±0.05mm, the length L1 of the end edge 204 is 3.5±0.05mm, and the end edge 204 is provided with an end edge back angle β1, the angle of which is 7°±1°.

[0033] Specifically, the design of the end blade 204, the second arc blade 201, the conical blade 202, and the first arc blade 203 is used to undertake the main cutting function and has the function of extrusion finishing.

[0034] In a preferred embodiment, the cutting edge 2 further includes a first circumferential cutting edge 205 formed on the outer wall of the blade body 7. The first circumferential cutting edge 205 is located between the second arc cutting edge 201 and the breaking edge 3. The first circumferential cutting edge 205 is tangentially connected to the second arc cutting edge 201. The width γ2 of the first circumferential cutting edge 205 is 0.3±0.05mm, the length L2 of the first circumferential cutting edge 205 is 1.1±0.05mm, and the first circumferential cutting edge 205 is provided with a first cutting edge clearance angle β2, the angle of the first cutting edge clearance angle β2 is 13°±2°.

[0035] In a preferred embodiment, the projected length L4 between the breaking edge 3 and the end edge 204 on the axis of the tool body 1 is 1.8 mm. This structural design is based on the following technical logic: the hole wall after being cut by the cutting edge 2 has a first roughness; the breaking edge 3 is used to perform secondary micro-cutting on the surface already cut by the cutting edge 2; and the hole wall after being cut by the breaking edge 3 has a second roughness. That is, the section from the bottom of the hole upwards for 1.8 mm (i.e., the length L4) to the hole opening is the second roughness surface, while the first roughness surface is retained within the 1.8 mm interval. It should be noted that the specific value of L4 can be adjusted according to actual processing requirements to adapt to deep hole processing scenarios with different precision requirements.

[0036] In a preferred embodiment, the breaking edge 3 includes a second circumferential cutting edge 301 formed on the outer wall of the blade body 7. The gap between the second circumferential cutting edge 301 and the first circumferential cutting edge 205 in the radial direction of the blade body 1 is H. The width γ3 of the second circumferential cutting edge 301 is 0.3±0.02mm, the length L3 of the second circumferential cutting edge 301 is 0.1±0.02mm, and the second circumferential cutting edge 301 has a second cutting edge clearance angle β3 with an angle of 5°±2°. By providing the second circumferential cutting edge 301, the edge strength is increased, greatly improving the blade life.

[0037] In a preferred embodiment, the second circumferential cutting edge 301 includes a rounded corner cutting edge 3011 and a flat cutting edge 3012. The rounded corner cutting edge 3011 is tangent to the flat cutting edge 3012. The radius of the rounded corner cutting edge 3011 is R3. The gap formed between the flat cutting edge 3012 and the first circumferential cutting edge 205 in the radial direction of the cutter body 1 is H. The range of H is 0.002 to 0.006 mm. In this embodiment, H is 0.004 mm. That is to say, the surface cut by the destructive blade 3 is rougher than the surface cut by the cutting blade 2. The protrusion height is 0.004 mm, which directly constitutes the second roughness Rmax value. That is, the surface after being cut by the destructive blade 3 will form an oil storage structure similar to a thread shape. This oil storage structure can hold lubricating oil. The maximum depth of this oil storage structure is 0.004 mm.

[0038] In a preferred embodiment, the breaking blade 3 further includes a back cone portion 302 formed on the side wall of the blade body 7. The back cone portion 302 is located at the rear end of the second circumferential cutting edge 301 along the axial direction of the blade body 1. The back cone portion 302 is inclined inward toward the handle 4. The included angle between the back cone portion 302 and the axial direction of the blade body 1 is α2, where α2 is 10°±2°.

[0039] Specifically, based on the feed direction of the reamer, the cutting edge 2 in the cutting insert 5 is located in front of the breaking edge 3, and the breaking edge 3 protrudes from the cutting edge 2. This design ensures that the diameter of the hole section processed by the breaking edge 3 is slightly larger than the diameter of the area processed by the cutting edge 2 during tool retraction, forming a physical isolation zone. This prevents the cutting edge 2 from performing secondary cutting on the hole wall surface that already has a second roughness during tool retraction, effectively ensuring the independence and stability of the two roughness structures of the inner wall of the deep hole.

[0040] Compared with the prior art, the beneficial effects of this utility model are: (1) The reamer of this utility model is equipped with a double-edged cutting blade 5 structure with a cutting edge 2 and a breaking edge 3. The cutting edge 2 is used to cut the wall of the deep hole and undertakes the main cutting function. The hole wall after being cut by the cutting edge 2 has a first roughness. The breaking edge 3 is located behind the cutting edge 2 and protrudes from the cutting edge 2 in the radial direction of the tool body 1. It can perform micro-cutting on the surface of the hole wall cut by the cutting edge 2 to destroy the smoothness of the deep hole wall. The hole wall after being cut by the breaking edge 3 has a second roughness. The cutting edge 2 and the breaking edge 3 work together in a single feed process. The reamer can achieve synchronous processing of two surfaces with different roughnesses on the inner wall of the deep hole of the same diameter, avoiding the clamping error caused by multiple tool changes and adjustments in the traditional process. (2) The breaking blade 3 of this utility model protrudes from the cutting blade 2 in the radial direction of the blade body 1, and the protrusion height is H. That is to say, the surface cut by the breaking blade 3 is rougher than the surface cut by the cutting blade 2. The protrusion height H directly constitutes the second roughness Rmax value. That is, the surface after being cut by the breaking blade 3 will form an oil storage structure similar to a thread shape. This oil storage structure can hold lubricating oil. The maximum depth of this oil storage structure is H. (3) The cutting edge 2 of this utility model adopts a composite cutting edge design, which is composed of the second arc cutting edge 201, the conical cutting edge 202 and the first arc cutting edge 203 connected in sequence. This structure completes the 30° conical surface forming of the bottom of the deep hole and the double-segment R0.4mm rounded corner transition simultaneously in one feed process, transforming the traditional step-by-step processing into continuous processing, eliminating the cumulative dimensional error caused by process connection, and ensuring the accuracy of the feature position and shape of the bottom of the deep hole.

[0041] The above description is based on the preferred embodiments of this utility model. Through the above description, those skilled in the art can make various changes and modifications without departing from the technical concept of this utility model. The technical scope of this utility model is not limited to the contents of the specification, but must be determined by the scope of the claims.

Claims

1. A reamer with controllable roughness for machining deep holes, characterized in that, include: The tool body (1), the tool holder (4) disposed at the rear end of the tool body (1), and the cutting blade (5) disposed at the front end of the tool body (1) The cutting blade (5) has a cutting edge (2) and a breaking edge (3). The cutting edge (2) is located in front of the breaking edge (3). The breaking edge (3) is closer to the shank (4) than the cutting edge (2). The cutting edge (2) extends from the front end of the tool body (1) to the outer peripheral surface of the tool body (1) for cutting the wall of the deep hole. The breaking edge (3) is disposed on the outer peripheral surface of the tool body (1) and protrudes radially from the cutting edge (2) of the tool body (1) with a protrusion height of H. The breaking edge (3) is used to process an oil storage structure of a predetermined depth on the surface of the deep hole wall. The predetermined depth of the oil storage structure is H. The cutting blade (5) includes a blade body (7), a cutting edge (2) formed at the front of the blade body (7), and a breaking edge (3) formed at the middle of the blade body (7). The blade body (7) is mounted on the front end of the tool body (1). The cutting edge (2) includes a second arc edge (201), a conical edge (202), and a first arc edge (203) arranged sequentially along the direction away from the tool holder (4). The second arc edge (201), the conical edge (202), and the first arc edge (203) are all formed on the outer side wall of the blade body (7). The conical edge (202) connects the first arc edge (203) and the second arc edge (201) and is inclined in the direction away from the axis of the tool body (1). The radius of the first arc edge (203) is R1, the radius of the second arc edge (201) is R2, and the included angle between the conical edge (202) and the axis of the tool body (1) is α1. The cutting edge (2) further includes an end edge (204) formed on the front end face of the blade body (7) and a first circumferential cutting edge (205) formed on the outer side wall of the blade body (7). The end edge (204) is tangentially connected to the first arc edge (203). The end edge (204) is provided with an end edge (204) rear angle. The first circumferential cutting edge (205) is located between the second arc edge (201) and the breaking edge (3). The first circumferential cutting edge (205) is tangentially connected to the second arc edge (201). The first circumferential cutting edge (205) is provided with a first cutting edge rear angle. The breaking edge (3) includes a second circumferential cutting edge (301) formed on the outer wall of the blade body (7). The second circumferential cutting edge (301) includes a rounded corner cutting edge (3011) and a flat cutting edge (3012). The rounded corner cutting edge (3011) is tangent to the flat cutting edge (3012). The radius of the rounded corner cutting edge (3011) is R3. The gap formed between the flat cutting edge (3012) and the first circumferential cutting edge (205) in the radial direction of the blade body (1) is H. The range of H is 0.002 to 0.006 mm. The second circumferential cutting edge (301) is provided with a second cutting edge back angle.

2. A reamer with controllable roughness as described in claim 1, characterized in that, The cutter body (1) is provided with a chip removal groove (101), which extends axially from the front end of the cutter body (1) toward the shank (4), and the cutting blade (5) is embedded in the chip removal groove (101).

3. A reamer with controllable roughness as described in claim 1, characterized in that, The number of cutting blades (5) is multiple, and the multiple cutting blades (5) are arranged in a ring array around the outer circumference of the cutter body (1).

4. A reamer with controllable roughness as described in claim 1, characterized in that, The reamer is provided with a central water outlet hole (6), which extends from the front end face of the reamer body (1) through the reamer body (1) and the handle (4) to the rear end face of the handle (4).

5. A reamer with controllable roughness as described in claim 1, characterized in that, The width γ1 of the end blade (204) is 0.3±0.05mm, the length L1 of the end blade (204) is 3.5±0.05mm, and the rear angle β1 of the end blade (204) is 7°±1°.

6. A reamer with controllable roughness as described in claim 1, characterized in that, The width γ2 of the first circumferential cutting edge (205) is 0.3±0.05mm, the length L2 of the first circumferential cutting edge (205) is 1.1±0.05mm, and the angle β2 of the first cutting edge is 13°±2°.

7. A reamer with controllable roughness as described in claim 1, characterized in that, The width γ3 of the second circumferential cutting edge (301) is 0.3±0.02mm, the length L3 of the second circumferential cutting edge (301) is 0.1±0.02mm, and the angle β3 of the back angle of the second cutting edge is 5°±2°.

8. A reamer with controllable roughness as described in claim 1, characterized in that, The blade body (1) is coaxially arranged with the blade holder (4) and integrally formed, and the cutting blade (5) is welded to the blade body (1).

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