A chip breaking method for oil perforating gun thread machining

Abstract

This invention discloses a chip-breaking method for thread cutting in oil perforating guns, relating to the field of thread chip-breaking technology. The method includes the following steps: a. Setting thread chip-breaking parameters according to processing requirements: thread minor diameter D1, single-blade thread depth of cut ap, thread pitch p, thread height h, effective thread length L, radial feed and retraction f, axial feed m, axial retraction r, and thread starting point position L1; b. Calculating the initial thread cutting starting position, number of thread teeth, and number of thread cutting cycles based on the parameters given in step a; c. Setting the thread cutting tool at the thread cutting starting position based on the parameters given in step a and the parameters calculated in step b, and then performing a slanted, segmented thread cutting method. This method produces short, strip-shaped chips, avoiding chip entanglement with the tool. While achieving automatic chip breaking for oil perforating gun threads, it also significantly improves thread accuracy and tool life, demonstrating good results in field applications.

Description

Technical Field

[0001] This invention relates to the field of thread chip breaking technology, and specifically to a chip breaking method for thread cutting in oil perforating guns. Background Technology

[0002] An oil perforating gun is a tool used in oil and gas extraction. It creates holes in underground wells to allow oil and gas to flow out smoothly. The perforating gun is a tubular structure with internal sealing surfaces and threads. These design elements ensure the stability and reliability of the perforating gun under high pressure and impact, prevent oil and gas leakage, and facilitate assembly and disassembly. Therefore, the machining quality of the sealing surfaces and threads plays a crucial role in the performance of the perforating gun.

[0003] Currently, the most efficient and effective method for machining the sealing surface and threads of perforating guns is to use CNC lathes for turning. However, during the thread machining process of perforating guns, the chips cannot be cut off in a timely and effective manner, resulting in long strips of chips often getting tangled on the tool. This not only affects the tool life and the machining quality of the perforating gun, but also restricts the further development of automation in perforating gun machining. Summary of the Invention

[0004] The purpose of this invention is to provide a chip-breaking method for thread cutting in oil perforating guns, which produces short, strip-shaped chips to prevent them from tangling with the tool. This method achieves automatic chip breaking while significantly improving thread accuracy and tool life, and has shown good results in field applications.

[0005] This invention is achieved through the following technical solution:

[0006] A chip-breaking method for thread cutting in oil perforating guns includes the following steps:

[0007] a. Set the thread chip breaking machining parameters according to the machining requirements: thread minor diameter D1, single-blade thread cutting depth ap, thread pitch p, thread height h, effective thread length L, radial feed and retraction f, axial feed m, axial retraction r, thread starting point position L1.

[0008] b. Based on the parameters given in step a, calculate the starting position of the initial thread cutting, the number of thread teeth, and the number of thread cutting cycles;

[0009] c. Based on the parameters given in step a and the parameters calculated in step b, set the thread cutting tool at the starting position of thread cutting, and then perform a slanted entry segmented thread cutting method to achieve automatic chip breaking in oil perforation gun thread processing.

[0010] Furthermore, in step b, the initial tool starting position for thread cutting is obtained as follows:

[0011] The starting positions for thread cutting are denoted as (X1, Z1), where X1 is the radial starting point of the thread and Z1 is the axial starting point of the thread. X1 and Z1 satisfy the following equations (Ⅰ) and (Ⅱ):

[0012] X1 = D1 + ap - f (Ⅰ);

[0013] Z1 = -(L1 - P)(Ⅱ).

[0014] Furthermore, in step b, the number of thread teeth N is calculated using the following formula (Ⅲ):

[0015] N = L / p(Ⅲ).

[0016] Furthermore, in step b, the value of N is taken as an integer. When the value of N is not an integer, it is rounded down to the nearest integer. The last pitch axial feed amount m1 = L - L1 - Np.

[0017] Furthermore, in step b, the number of thread cutting cycles n is calculated using the following formula (Ⅳ):

[0018] n = 2h / ap(Ⅳ).

[0019] Furthermore, in step b, the value of n is taken as an integer. When the value of n is not an integer, the rounding method is used to round it up. Then the depth of cut of the last thread cutting cycle is ap1 = 2h - ap(n-1).

[0020] Furthermore, in step c, the thread cutting method is as follows:

[0021] a1. Radial feed increases the depth of cut by one thread back, i.e., radial feed ap;

[0022] b1. Inclined thread feed, i.e., radial feed f and axial feed m simultaneously;

[0023] c1. Turn the first thread in the first cycle, i.e., the axial feed m;

[0024] d1. Oblique thread retraction, i.e., radial retraction f while axial feed m;

[0025] e1. Retract to the starting point of the next pitch, i.e., axial retraction r;

[0026] f1. Repeat steps b1 to e1 to complete the first cycle of thread cutting;

[0027] g1. Repeat steps a1 to f1 until all thread cutting is completed.

[0028] Furthermore, when the value of n calculated by equation (Ⅳ) in step b is not an integer, the rounding method is used to round it up. Then, the depth of cut ap1 of the last thread cutting cycle is 2h - ap(n-1). In the thread cutting method, steps a1 to f1 are repeated until the penultimate thread cutting cycle is completed.

[0029] h1. Radial feed increases by one thread back depth, i.e., radial feed ap1, ap1 = 2h - ap(n-1);

[0030] i1. Inclined thread feed, i.e., radial feed f and axial feed m at the same time;

[0031] j1. Turn the last thread of the first cycle, i.e., the axial feed m;

[0032] k1. Oblique thread retraction, that is, radial retraction f while axial feed m;

[0033] l1. Return to the starting point of the next pitch, i.e., axial retraction r;

[0034] m1. Repeat steps i1 to l1 until all thread cutting is completed.

[0035] Furthermore, when the N value calculated by equation (Ⅲ) in step b is not an integer, it is rounded down to the nearest integer, and the last pitch axial feed amount m1 = L - L1 - Np; in the thread cutting method, steps a1 to f1 are repeated until the penultimate cycle of thread cutting is completed.

[0036] h1. Radial feed increases by one thread back depth, i.e., radial feed ap;

[0037] i1. Inclined thread feed, i.e., radial feed f and axial feed m at the same time;

[0038] j1. Turn the last thread of the first cycle, i.e., axial feed m1, m1=L-L1-Np;

[0039] k1. Oblique thread retraction, that is, radial retraction f while axial feed m;

[0040] l1. Return to the starting point of the next pitch, i.e., axial retraction r;

[0041] m1. Repeat steps i1 to l1 until all thread cutting is completed.

[0042] Furthermore, in step c, the entire thread is divided into several segments for segmented cutting using an oblique entry segmented cutting method, i.e., one pitch is one segment. The thread chips obtained by the oblique entry segmented cutting method are short strips and can achieve automatic chip breaking of the thread.

[0043] Compared with the prior art, the present invention has the following advantages and beneficial effects:

[0044] I. In this invention, the automatic chip breaking mechanism for perforating gun thread machining solves the problem of long iron chips getting tangled on the tool during the internal threading process of perforating gun, which easily scratches the gun barrel sealing surface and the tool. The thread machining quality and tool life are both greatly improved.

[0045] Second, the automatic chip breaking mechanism in the threading process of the perforating gun solves the problem of tools scratching the sealing surface of the gun barrel and the tool when manually cleaning the iron filings wrapped around the perforating gun or the cutting tool, while also reducing the safety risks of manual operation.

[0046] Third, the automatic chip breaking technology for thread cutting with a perforating gun in this invention adopts a segmented cutting method, which reduces tool processing resistance, promotes rapid chip heat dissipation, and results in more stable thread processing quality.

[0047] Fourth, in this invention, the automatic chip breaking mechanism in the threading of the perforating gun realizes the automation and unmanned operation of the perforating gun, which can greatly save the labor cost of perforating gun processing. Attached Figure Description

[0048] Figure 1 Drawings for machining perforating guns.

[0049] Figure 2 This is the toolpath for the thread breaking program of the perforating gun.

[0050] Figure 3 Comparison of iron filings produced by thread cutting with a perforating gun. Detailed Implementation

[0051] The present invention will be further described in detail below with reference to embodiments, but the implementation of the present invention is not limited thereto.

[0052] Example 1

[0053] To facilitate public understanding of this solution, this embodiment uses the Tr78×4 type perforating gun for chip breaking during thread machining as an example. The perforating gun machining drawings are referenced. Figure 1 The above and other objects and features of the present invention will become clearer from the following description taken in conjunction with the accompanying drawings. The following embodiments are used to illustrate the present invention, but are not intended to limit the scope of the invention.

[0054] A chip-breaking method for thread cutting in oil perforating guns, relating to the field of thread chip breaking technology, includes the following steps:

[0055] first step:

[0056] Set the following thread chip breaking machining parameters according to the machining requirements: thread minor diameter D1 = 74.2 mm, single-blade thread depth ap = 0.3 mm, thread pitch p = 4 mm, thread height h = 2.25 mm, effective thread length L = 60 mm, radial feed and retraction f = 5 mm (greater than 2 h), axial feed m = 4 mm (preferably an integer multiple of the pitch), axial retraction r = 8 mm (preferably an integer multiple of the pitch), thread starting point position L1 = 25 mm.

[0057] Step Two:

[0058] Based on the parameters given in the first step, calculate the starting position of the initial thread cutting, the number of thread teeth, and the number of thread cutting cycles;

[0059] In this step, the starting position for the initial thread cutting is obtained as follows:

[0060] The starting positions for thread cutting are denoted as (X1, Z1), where X1 is the radial starting point of the thread and Z1 is the axial starting point of the thread. X1 and Z1 satisfy the following equations (Ⅰ) and (Ⅱ):

[0061] X1 = D1 + ap - f (Ⅰ);

[0062] Z1 = -(L1 - P) (Ⅱ),

[0063] The calculation yields X1 = D1 + ap - f = 74.2 + 0.3 - 5 = 69.5, Z1 = -(L1 - P) = -(25 - 4) = -21, meaning the starting position for thread cutting is recorded as (69.5, -21).

[0064] The number of threads N is calculated using the following formula (Ⅲ):

[0065] N=(L-L1) / p=(60-25) / 4=8.75(Ⅲ).

[0066] In this step, the value of N is taken as an integer. When the value of N is not an integer, it is rounded down to the nearest integer, that is, N=8, and the last pitch axial feed amount m1=L-L1-Np=60-25-8*4=3mm.

[0067] The number of thread cutting cycles n is calculated using the following formula (Ⅳ):

[0068] n=2h / ap=2*2.25 / 0.3=15 (IV).

[0069] Step 3:

[0070] Based on the parameters given in the first step and the parameters calculated in the second step, a thread breaking program is compiled. The thread cutting tool is set at the starting position of thread cutting, and then the inclined segmented thread cutting method is used to realize automatic chip breaking in oil perforating gun thread processing.

[0071] The thread cutting method is as follows:

[0072] a1. Increase the radial feed by one thread back depth ap, i.e., radial feed of 0.3mm;

[0073] b1. Inclined thread feed, i.e., radial feed f is 5mm while axial feed m is 4mm;

[0074] c1. The first thread is cut in the first cycle, i.e., the axial feed m is 4mm;

[0075] d1. Oblique thread retraction, i.e., radial retraction f is 5mm while axial feed m is 4mm;

[0076] e1. Return to the starting point of the next pitch, i.e., the axial retraction r is 8mm;

[0077] f1. Repeat steps b1 to e1 until the first cycle of thread cutting is completed;

[0078] g1. Repeat steps a1 to f1 until the penultimate cycle of thread cutting is completed;

[0079] h1. Increase the radial feed by one thread back depth ap, i.e., radial feed of 0.3mm;

[0080] i1. Inclined thread feed, i.e., radial feed f is 5mm while axial feed m is 4mm;

[0081] j1. Turn the last thread of the first cycle, that is, the axial feed m1 is 3mm;

[0082] k1. Oblique thread retraction, that is, radial retraction f is 5mm while axial feed m is 4mm;

[0083] l1. Retract to the next pitch starting point, i.e., axial retraction r is 8mm;

[0084] m1. Repeat steps i1 to l1 until all thread cutting is completed.

[0085] In this embodiment, the toolpath reference for the thread breaking program of the perforating gun is as follows. Figure 2 .

[0086] In this step, the entire thread is divided into several segments using a slanted cutting method, with one pitch constituting one segment. This results in short, strip-shaped thread chips. (See attached diagram.) Figure 3 This enables automatic chip breaking of the thread.

[0087] This method uses a slanted, segmented cutting approach to cut the threads of the perforating gun, achieving automatic chip breaking during thread processing. This effectively avoids tool tip wear caused by thread entanglement during processing, significantly improving the quality and stability of perforating gun thread processing, while also greatly extending the service life of the thread inserts.

[0088] The above description is merely a preferred embodiment of the present invention and is not intended to limit the present invention in any way. Any simple modifications or equivalent changes made to the above embodiments based on the technical essence of the present invention shall fall within the protection scope of the present invention.

Claims

1. A chip-breaking method for thread cutting in oil perforating guns, characterized in that, Includes the following steps: a. Set the thread chip breaking machining parameters according to the machining requirements: thread minor diameter D1, single-blade thread cutting depth ap, thread pitch p, thread height h, effective thread length L, radial feed and retraction f, axial feed m, axial retraction r, thread starting point position L1. b. Based on the parameters given in step a, calculate the starting position of the initial thread cutting, the number of thread teeth N, and the number of thread cutting cycles n; In this step, the number of thread cutting cycles n is calculated using the following formula (Ⅳ): n=2h / ap(Ⅳ) The value of n is taken as an integer. When the value of n is not an integer, the rounding method is used to round up. Then the depth of cut of the last thread cutting cycle is ap1 = 2h - ap(n-1). c. Based on the parameters given in step a and the parameters calculated in step b, set the thread cutting tool at the starting position of thread cutting, and then perform the inclined segmented thread cutting method to achieve automatic chip breaking in oil perforating gun thread processing. The method for thread cutting is as follows: a1. Radial feed increases by one thread back depth, i.e., radial feed ap; b1. Inclined thread feed, i.e., radial feed f and axial feed m simultaneously; c1. The first thread is cut in the first cycle, i.e., the axial feed m; d1. Oblique thread retraction, i.e., radial retraction f while axial feed m; e1. Retract to the starting point of the next pitch, i.e., axially retract the tool r; f1. Repeat steps b1~e1 to complete the first cycle of thread cutting; g1. Repeat steps a1 to f1 until all thread cutting is completed.

2. The chip-breaking method for thread cutting in oil perforating guns according to claim 1, characterized in that: In step b, the initial tool starting position for thread cutting is obtained as follows: The starting positions for thread cutting are denoted as (X1, Z1), where X1 is the radial starting point of the thread and Z1 is the axial starting point of the thread. X1 and Z1 satisfy the following equations (I) and (II): X1 = D1 + ap - f (Ⅰ); Z1 = -(L1 - P) (II).

3. The chip-breaking method for thread cutting in oil perforating guns according to claim 1, characterized in that: In step b, the number of thread teeth N is calculated using the following formula (Ⅲ): N = L / p (Ⅲ).

4. The chip-breaking method for thread cutting in oil perforating guns according to claim 3, characterized in that: In step b, the value of N is taken as an integer. When the value of N is not an integer, it is rounded down to the nearest integer. The last pitch axial feed amount m1 = L - L1 - Np.

5. The chip-breaking method for thread cutting in oil perforating guns according to claim 1, characterized in that: When the value of n in step b is not an integer, in the thread cutting method, steps a1 to f1 are repeated until the penultimate cycle of thread cutting is completed. h1. Radial feed increases by one thread back depth, i.e., radial feed ap1, ap1=2h-ap(n-1); i1. Inclined thread feed, i.e., radial feed f and axial feed m simultaneously; j1. Turn the last thread of the first cycle, i.e., the axial feed m; k1. Oblique thread retraction, i.e., radial retraction f while axial feed m; l1. Return to the starting point of the next pitch, i.e., axial retraction r; m1. Repeat steps i1 to l1 until all thread cutting is completed.

6. The chip-breaking method for thread cutting in oil perforating guns according to claim 4, characterized in that: When the N value calculated by formula (Ⅲ) in step b is not an integer, it is rounded down to the nearest integer. The last pitch axial feed amount m1 = L - L1 - Np; in the thread cutting method, steps a1 to f1 are repeated until the penultimate cycle of thread cutting is completed. h1. Radial feed increases by one thread back depth, i.e., radial feed ap; i1. Inclined thread feed, i.e., radial feed f and axial feed m simultaneously; j1. Turn the last thread of the first cycle, i.e., axial feed m1, m1=L-L1-Np; k1. Oblique thread retraction, i.e., radial retraction f while axial feed m; l1. Return to the starting point of the next pitch, i.e., axial retraction r; m1. Repeat steps i1 to l1 until all thread cutting is completed.

7. A chip-breaking method for thread cutting in oil perforating guns according to claim 6, characterized in that: In step c, the entire thread is divided into several segments by a slanted cutting method, with one pitch as one segment. The thread chips obtained by the slanted cutting method are short strips and can achieve automatic chip breaking.

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