Thread cutter and thread machining method

Abstract

The invention belongs to the technical field of machining, and particularly relates to a thread cutter and a thread machining method. The threaded cutter comprises a cutter body, a threaded rod and a threaded rod, wherein a mounting hole is formed in the middle of the cutter body; the at least one cutter tooth is uniformly arranged on the cutter body along the circumferential direction, the front side surface of the cutter tooth is provided with a front cutter surface and a chip groove, the left side and the right side of the cutter tooth are respectively provided with a left cutter surface and a right cutter surface, the top of the cutter tooth is provided with an upper cutter surface, and the cutter front angle of the front cutter surface is 2-10 degrees.

Description

Technical Field

[0001] The present invention belongs to the technical field of mechanical processing, and in particular, relates to a thread tool and a thread processing method. Background Art

[0002] The domestic tight oil and gas and shale gas resources are huge, but the reservoir matrix has poor physical properties, strong heterogeneity and low permeability, and staged fracturing technology needs to be applied during development. In order to solve the contradictions between the demand for high-pressure wellbore for reservoir transformation, the requirement for low-cost well construction for production benefits, the requirement for large wellbore diameter for production technology and safe and efficient exploitation, a tight oil and gas tail pipe tie-back uncemented fracturing wellbore technology is proposed. The plug-in threaded slip anchoring mechanism and metal-supported tie-back plug combination are used to achieve the isolation between the oil casing annulus, providing a low-cost, high-pressure and easy-to-operate process technology for the efficient and safe development of tight oil and gas reservoirs and shale gas reservoirs. The anchoring and unlocking recovery operations are simple, safe and reliable.

[0003] The plug-in threaded slip anchoring mechanism is a locking slip designed on the upper end of the return plug, which is used in conjunction with the locking structure on the return tube. The outer circle of the locking slip is designed as a tapered male thread (left-hand buckle), the top of the male buckle is a plane, the bottom of the tooth is a cone (1:16), and the maximum thread depth is 2.88mm. The matching return tube is designed as a tapered female thread (left-hand buckle), the top of the tooth is a cone (1:16), the bottom of the tooth is a plane, and the maximum thread depth is 2.68mm. During the scientific research and trial production stage, the tool was manually sharpened according to the thread tooth shape and parameters, and the carbide YG8 welded blade was used. There were great limitations in the choice of tool structure and cutting parameters, and a lot of time was spent on manual sharpening. The tool had poor adaptability, wore quickly, and the cutting efficiency could not be improved. In addition, the processing quality of the thread was unstable.

[0004] Therefore, there is an urgent need to develop a thread tool that can efficiently process tapered male threads and tapered female threads. Summary of the invention

[0005] In view of the technical problem mentioned above, the present invention aims to provide a thread cutter capable of efficiently processing tapered male threads and tapered female threads.

[0006] The invention also provides a thread processing method, which can process tapered male threads and tapered female threads.

[0007] According to the present invention, there is provided a thread tool, comprising:

[0008] A knife body, wherein a mounting hole is provided in the middle of the knife body;

[0009] At least one cutting tooth is uniformly arranged on the cutting body along the circumferential direction, a rake face and a chip groove are arranged on the front side of the cutting tooth, a left cutting face and a right cutting face are arranged on the left and right sides of the cutting tooth respectively, an upper cutting face is arranged on the top of the cutting tooth, and the tool rake angle of the rake face is 2° to 10°.

[0010] In a specific embodiment, the chip removal groove is configured as an arc surface.

[0011] In a specific embodiment, the radius of the chip removal groove is 0.5 mm to 1.5 mm.

[0012] In a specific embodiment, the tool back angle of the right tool surface is 5° to 10°.

[0013] In a specific embodiment, a blade tip arc surface is arranged between the upper blade surface and the left blade surface, and between the upper blade surface and the right blade surface.

[0014] In a specific embodiment, the radius of the arc surface of the blade tip is 0.1 mm to 0.7 mm.

[0015] In a specific embodiment, the angle between the left cutting surface and the vertical reference plane is 5° to 10°.

[0016] In a specific embodiment, the angle between the right blade surface and the vertical reference plane is 5° to 10°.

[0017] In a specific embodiment, the mounting hole comprises a tapered hole, and the cone surface angle of the tapered hole is 50° to 70°.

[0018] According to the present invention, a thread processing method is also provided. When processing a female thread, the inner wall of the workpiece is a conical surface, and the thread tool provided by the present invention is used to cut from the inside to the outside parallel to the axis of the workpiece; when processing a male thread, the outer wall of the workpiece is a cylindrical surface, and the thread tool provided by the present invention is used to cut from the inside to the outside oblique to the axis of the workpiece.

[0019] Compared with the prior art, the advantages of the present application are as follows.

[0020] The present invention designs a special thread cutter for the D-shaped left-handed thread structure for tail pipe tie-back fracturing, optimizes the tool geometry through continuous production site processing tests and verifications, thereby improving thread processing efficiency.

[0021] According to the geometric structure of the thread cutter, the present invention formulates an efficient processing path and cutting method, compiles a high-quality CNC processing program, realizes the efficient processing requirements of special and dedicated precision threads, greatly improves production and processing efficiency, meets the technical needs of high-end products for tail pipe fracturing in the solid completion market, and promotes the efficient and safe development of tight oil and gas reservoirs. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] The present invention will be described below with reference to the accompanying drawings.

[0023] Figure 1 A schematic diagram showing an embodiment of a thread cutter for machining a female thread according to the present invention;

[0024] Figure 2 A schematic front view of a thread cutter for machining a female thread according to the present invention is shown;

[0025] Figure 3 A schematic diagram showing an embodiment of a cutter tooth of a thread tool for machining a female thread according to the present invention;

[0026] Figure 4 Shows Figure 3 The cross-sectional structure in the EE direction;

[0027] Figure 5 Shows Figure 2 The cross-sectional structure in the AA direction;

[0028] Figure 6 A schematic diagram showing an embodiment of a thread cutter for machining a male thread of the present invention;

[0029] Figure 7 A schematic diagram of female thread machining is shown;

[0030] Figure 8 A schematic diagram of male thread machining is shown.

[0031] The reference numerals in the figure are:

[0032] 1. Cutter body; 2. Rake face; 3. Mounting hole; 31. Tapered hole; 4. Right cutting face; 5. Arc face of cutting tip; 6. Upper cutting face; 7. Main cutting edge; 9. Left cutting face; 10. Chip groove; 20. Cutter teeth; 30. Female thread workpiece; 40. Male thread workpiece; 100. Thread tool.

[0033] In the present application, all drawings are schematic drawings, which are only used to illustrate the principles of the present invention and are not drawn according to the actual scale. DETAILED DESCRIPTION

[0034] The present invention will be described below with reference to the accompanying drawings.

[0035] It should be noted that the directional terms or qualifiers "upper", "lower", "front", "back", "left", "right", etc. used in this application are all relative to the referenced Figure 3 They are not intended to define the absolute positions of the components involved, but may vary depending on the specific circumstances.

[0036] Figure 1 The structure of the thread tool 100 according to the present invention is shown. Figure 1 As shown, the thread tool 100 mainly includes a tool body 1 and tool teeth 20 .

[0037] In this embodiment, a mounting hole 3 is provided in the middle of the cutter body 1. The mounting hole 3 passes through the cutter body 1 and is used to cooperate with a clamping screw so that the cutter body 1 can be fixed on the machine tool.

[0038] At least one blade tooth 20 is evenly arranged along the circumferential direction on the circumferential edge of the blade body 1. In this embodiment, three blade teeth 20 are evenly arranged on the blade body 1 at intervals along the circumferential direction.

[0039] like Figure 1 and Figure 3 As shown, a rake face 2 and a chip removal groove 10 are provided on the front side of the tooth 20. A left blade face 9 and a right blade face 4 are provided on the left and right sides of the tooth 20, respectively. An upper blade face 6 is provided on the top of the tooth 20. The front end of the upper blade face 6 and the upper end of the rake face 2 form a main cutting edge 7.

[0040] In this embodiment, the tool rake angle of the front cutting surface 2 is 2° to 10°. Figure 5 As shown, the tool rake angle is the angle between the front cutting edge 2 and the end face of the tool body 1 ( Figure 5 In a preferred embodiment, the tool rake angle of the front cutting surface 2 is 5°.

[0041] According to the present invention, the chip removal groove 10 is configured as a circular arc surface. Figure 5 As shown, the radius R1 of the chip groove 10 is 0.5 mm to 1.5 mm. In a preferred embodiment, the radius R1 of the chip groove 10 is 1 mm.

[0042] According to the present invention, the back angle of the tool on the right blade surface 4 is 5° to 10°. Figure 3 and Figure 4 As shown, the tool back angle is the right blade 4 and Figure 4 In a preferred embodiment, the tool back angle is 7°±10′.

[0043] According to the present invention, Figure 1 and Figure 3 As shown, a blade tip arc surface 5 is provided between the upper blade surface 6 and the left blade surface 9 and between the upper blade surface 6 and the right blade surface 4. In this embodiment, the radii R2 and R3 of the blade tip arc surface 5 are 0.1 mm to 0.7 mm. In a preferred embodiment, the radii R2 and R3 of the blade tip arc surface 5 are both 0.3 mm.

[0044] According to the present invention, the angle between the left blade surface 9 and the right blade surface 4 and the vertical reference plane is 5° to 10°. Figure 3As shown, the angle between the left blade surface 9 and the right blade surface 4 and the vertical reference plane is θ4, and the angle between the right blade surface 4 and the vertical reference plane is θ5. In a preferred embodiment, the angle between the left blade surface 9 and the right blade surface 4 and the vertical reference plane is 6°±10′.

[0045] According to the present invention, the mounting hole 3 comprises a tapered hole 31, and the cone angle of the tapered hole 31 is 50° to 70°. Figure 5 As shown, the cone surface angle of the cone hole 31 is θ1. In a preferred embodiment, the cone surface angle of the cone hole 31 is 60°.

[0046] In a specific embodiment, the thread tool 100 provided according to the present invention is used to process D-shaped left-handed anchoring male and female threads, and is divided into a thread tool for processing female threads and a thread tool for processing male threads.

[0047] Taking the thread cutter 100 for processing female threads as an example, the thread cutter 100 includes an integrally formed cutter body 1 and three cutter teeth 20 arranged on the cutter body 1, which are at an angle of 60° to each other. A center positioning mounting hole 3 is arranged at the center of the cutter body 1, and the hole diameter of the mounting hole 3 is φ6.6mm. The conical surface of the conical hole 31 at the position where it cooperates with the clamping screw is 60°. The thickness of the cutter body 1 is 6.75mm, and the shape and position tolerance of the upper and lower parallelism is 0.012mm. It is fixed to the tool bar of the machine tool by the clamping screw to ensure accurate positioning and firm installation. The radius of the chip groove 10 is 1mm, which effectively reduces the resistance generated by breaking the chips, has good chip breaking and chip removal effects, and has uniform chip thickness. The tool rake angle θ2 is in the range of 2° to 10°, the cutting force is small, the chips are regular, and the cutting surface texture is relatively uniform. As the rake angle continues to increase, the cutter body becomes thinner. Considering the processing strength and sharpness of the tool tip, the tool rake angle is designed to be 5° to ensure the service life of the tool in actual production. The main function of the tool back angle θ5 is to reduce the friction between the tool back face and the machined surface and transition surface of the workpiece, and the effect on the cutting force is very small. The larger the tool back angle, the sharper the tool cutting edge, the smaller the volume of the tool body, and the lower the strength and heat dissipation performance. In this embodiment, the tool back angle is set to 7°±10′, and the cutting load is stable. The radius of the tool tip arc surface 5 is 0.1mm~0.7mm. As the radius of the tool tip arc increases, the heat dissipation performance of the tool tip is enhanced. At the same time, the number of arc edges involved in cutting increases, which increases the cutting force. The radius of the tool tip arc surface 5 is designed to be 0.3mm in this embodiment, which cooperates with the chip removal groove 10 in this embodiment to achieve good chip breaking and chip removal effects. The design tooth height of the cutter tooth 20 is 1.79mm, the effective tooth thickness is 3.32mm, the complete tooth height is 3.69mm, and the tooth width at the thread mid-diameter is 3.78mm. The angle between the left tool face 9 and the right tool face 4 and the vertical reference plane is 6°±10′, which reduces the cutting resistance and ensures the sharpness and strength of the cutting edge.

[0048] In a preferred embodiment, the thread cutter 100 uses a cemented carbide YG8 PVD TiAlN coating to strengthen the blade and coating strength.

[0049] According to the present invention, a thread processing method is also provided. Figure 7 As shown, when machining the female thread, the inner wall of the female thread workpiece 30 is a conical surface, and the thread cutter 100 provided by the present invention is used to move the tool from the inside to the outside parallel to the axis of the female thread workpiece 30, and the tool path is as shown in FIG. Figure 7 shown.

[0050] like Figure 8 As shown, when machining the male thread, the outer wall of the male thread workpiece 40 is a cylindrical surface. The thread cutter 100 provided by the present invention is used to cut from the inside to the outside at an angle to the axis of the male thread workpiece 40. The cutting path is as shown in FIG. Figure 8 shown.

[0051] In a specific embodiment, taking the female thread corresponding to the 8-5 / 8″×5-1 / 2″ tie-back sleeve and the locking slip as an example, the D-shaped thread is left-handed, and the processing method is exactly opposite to the conventional right-handed thread, requiring a tool to reversely pull and form.

[0052] The female thread is designed with a 1:16 taper on the top surface and a flat surface on the bottom. When machining the female thread, the first step is to complete the 1:16 taper surface of the thread through rough and fine machining, remove all machining allowances before turning the thread, and ensure the R3.2 finish requirement to form a Figure 7 The female thread workpiece 30 is shown in the figure. In the second step, the thread cutter 100 is used to turn the left-hand thread. The processing method is to reverse the right-hand tool chuck and cut from the inside to the outside to ensure the direction of the thread. During the cutting process, a fixed depth feed method is used, and each cutting depth ap = 0.1mm is used to obtain a smaller cutting force and avoid workpiece vibration. The tool path is shown in Figure 7 As shown, the tool path is a horizontal line, parallel to the central axis of the female thread workpiece 30, ensuring the special design of the D-type thread and the "bottom line of the tooth" as a horizontal line. In order to ensure high processing efficiency and surface quality, a higher cutting speed (96-120mm / min) is used. In the third step, since the "top surface of the tooth" is no longer processed when cutting the thread, deburring is required after the thread is formed to ensure the safety of the thread connection.

[0053] The male thread is designed with a 1:16 taper at the bottom and a flat top. When machining male threads, the first step is to complete the machining of the thread top diameter plane through rough and fine machining, remove all machining allowances before turning the thread, and ensure the R3.2 finish requirement to form a Figure 8 The male thread workpiece 40 is shown. In the second step, the thread cutter 100 is used to turn the left-hand thread. The thread cutter 100 is cut from the inside to the outside at a taper of 1:16. Figure 8 As shown, to ensure the direction of the thread rotation, the fixed depth feed method is also used, and the cutting depth ap = 0.1mm each time. The third step is to remove burrs from the formed thread to ensure the safety of the thread connection.

[0054] In the description of the present invention, it should be understood that the terms "first" and "second" are used for descriptive purposes only and should not be understood as indicating or implying relative importance or implicitly indicating the number of technical features indicated. Thus, a feature defined as "first" or "second" may explicitly or implicitly include one or more of the features. In the description of the present invention, the meaning of "plurality" is two or more, unless otherwise clearly and specifically defined.

[0055] In the present invention, unless otherwise clearly specified and limited, the terms "installed", "connected", "connected", "fixed" and the like should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection, or it can be an indirect connection through an intermediate medium, or it can be the internal communication of two components. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0056] In the description of this specification, the description with reference to the terms "one embodiment", "some embodiments", "examples", "specific examples", or "some examples" means that the specific features, structures, materials or characteristics described in conjunction with the embodiment or example are included in at least one embodiment or example of the present invention. In this specification, the schematic representation of the above terms does not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials or characteristics described may be combined in any one or more embodiments or examples in a suitable manner.

[0057] Finally, it should be noted that the above is only a preferred embodiment of the present invention and does not constitute any limitation to the present invention. Although the present invention has been described in detail with reference to the aforementioned embodiments, it is still possible for a person skilled in the art to modify the technical solutions described in the aforementioned embodiments or to replace some of the technical features therein by equivalents. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present invention shall be included in the protection scope of the present invention.

Claims

1. A thread tool, characterized in that: include: A knife body (1), wherein a mounting hole (3) is provided in the middle of the knife body (1); At least one cutting tooth (20) is evenly arranged on the cutting body (1) along the circumferential direction, a rake face (2) and a chip removal groove (10) are arranged on the front side of the cutting tooth (20), a left cutting face (9) and a right cutting face (4) are arranged on the left and right sides of the cutting tooth (20), an upper cutting face (6) is arranged on the top of the cutting tooth (20), and the tool rake angle of the rake face (2) is 2° to 10°.

2. The thread tool according to claim 1, characterized in that The chip removal groove (10) is configured as an arc surface.

3. The thread tool according to claim 2, characterized in that The radius of the chip removal groove (10) is 0.5 mm to 1.5 mm.

4. The thread tool according to claim 1, characterized in that The tool back angle of the right tool surface (4) is 5° to 10°.

5. The thread tool according to claim 1, characterized in that: A blade tip arc surface (5) is arranged between the upper blade surface (6) and the left blade surface (9), and between the upper blade surface (6) and the right blade surface (4).

6. The thread tool according to claim 5, characterized in that The radius of the knife tip arc surface (5) is 0.1 mm to 0.7 mm.

7. The thread tool according to claim 1, characterized in that The angle between the left blade surface (9) and the vertical reference plane is 5° to 10°.

8. The threading tool according to claim 1, characterized in that The included angle between the right blade surface (4) and the vertical reference plane is 5° to 10°.

9. The threading tool according to claim 1, characterized in that: The mounting hole (3) comprises a tapered hole (31), and the tapered surface angle of the tapered hole (31) is 50° to 70°.

10. A thread processing method, characterized in that: When machining the female thread, the inner wall of the workpiece is a conical surface, and the thread cutter according to any one of claims 1 to 9 is used to cut from the inside to the outside in parallel to the axis of the workpiece; When machining the male thread, the outer wall of the workpiece is a cylindrical surface, and the thread cutter according to any one of claims 1 to 9 is used to cut from the inside to the outside at an angle to the axis of the workpiece.

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