Thread repair method for numerical control lathe

Abstract

The application discloses a thread repairing method for a numerical control lathe, which comprises the following steps: determining the standard helix track of the numerical control lathe under the current coordinate system by using a thread cooperation tool; clamping the thread to be repaired on the numerical control lathe, preliminarily positioning the thread to be repaired by the thread cooperation tool, and finely adjusting the axial cutter to make the helix of the thread to be repaired coincide with the set helix of the lathe in the axial direction; determining the cutting starting point in the circumferential direction in the rotating mode before clamping by the scale on the thread cooperation tool, fastening the chuck, and completing the positioning and clamping; after the two key parameters, the cutting starting point in the axial direction and the cutting starting point in the circumferential direction, are perfectly matched, only the Z-axis parameter of the numerical control lathe needs to be finely adjusted to realize the thread repairing. The method can accurately coincide the helix of the numerical control lathe with the helix of the thread to be repaired, rapidly lock the space cutting starting point of the thread to be repaired after secondary clamping, and significantly improve the workpiece quality and machining efficiency.

Description

Technical Field

[0001] This invention relates to the field of machine tool clamping technology, and in particular to a thread repair method for CNC lathes. Background Technology

[0002] Drill pipe threads endure harsh conditions such as high pressure, corrosion, and frequent loading and unloading during drilling operations, making them prone to wear, corrosion, or localized damage. To ensure the safety and efficiency of drilling operations, damaged threads must be repaired. Traditional thread repair methods often rely on the operator's experience for tool setting and positioning, resulting in low positioning accuracy, low repair efficiency, and problems such as "cross-threading" or "tooth chipping," which seriously affect the quality and service life of the workpiece.

[0003] While some existing technologies offer optimized devices or programs, they still fail to effectively solve the problem of rapid and accurate alignment of the thread helix starting point after secondary clamping. Therefore, it is necessary to propose a thread repair method that is easy to operate, has controllable precision, and is suitable for CNC lathes. Summary of the Invention

[0004] The purpose of this invention is to provide a thread repair method for CNC lathes, which can quickly and accurately achieve spatial alignment of the thread to be repaired with the helix of the machine tool program, thereby improving repair quality and processing efficiency, and reducing reliance on operator skills.

[0005] To achieve the above objectives, the present invention adopts the following technical solution: A method for repairing threads on a CNC lathe includes: S1. Use a threaded tool to locate and determine the standard helical trajectory of the CNC lathe in the current coordinate system; S2. Clamp the thread to be repaired on the CNC lathe, initially position it using a thread fitting tool, and then finely adjust it with axial tool compensation to make the helix of the thread to be repaired coincide with the helix set on the lathe in the axial direction; achieve the coincidence of the helix of the thread to be repaired with the helix of the lathe, and ensure that the starting point of the tool in the axial direction of the thread to be repaired is precisely aligned with the starting point on the axis of the CNC thread lathe. S3. Before clamping, determine the starting point in the circumferential direction by rotating the tool according to the scale on the threaded tool, and tighten the chuck to complete the positioning and clamping; ensure that the recorded starting point in the circumferential direction coincides perfectly with the actual starting point through clamping; S4. Once the two key parameters of the starting point in the axial direction and the starting point in the circumferential direction are perfectly matched, only the Z-axis parameters on the CNC lathe need to be finely adjusted to achieve thread repair.

[0006] Optionally, a threaded fitting tool can be used as an alignment reference. The threaded fitting tool is threadedly connected to the thread to be repaired. The outer diameter and end face of the threaded fitting tool are used as references to determine the starting point in the axial direction and the starting point in the circumferential direction of the thread to be repaired, ensuring that the lathe spindle pitch corresponds to the circumferential starting point of the thread to be repaired.

[0007] Optionally, the distance from the end face of the threaded tool to the lathe chuck is measured to determine the lathe Z-axis parameters; the angle is converted according to the thread pitch, and the rotational position is corrected by tool compensation to complete the tool setting.

[0008] Optionally, the thread fitting tool is a pre-machined calibration sample that mates with the thread of the drill pipe being repaired.

[0009] In summary, the technical effects and advantages of this invention are as follows: A thread-fitting tool, prefabricated and aligned with the calibration sample (thread gauge), is used for alignment and positioning of the axial and circumferential bidirectional cutting reference. The Z-axis parameters are determined by the thread-fitting tool, and the pitch is converted to calculate the circumferential correction angle, resulting in high positioning accuracy. This invention is suitable for repairing tapered threads damaged by corrosion, impacts, or minor sticking. After calibration of the axial and circumferential bidirectional cutting points, only minor adjustments to the Z-axis parameters are needed to begin repair. The debugging process is clearly structured, and the source of positioning error is controllable. Attached Figure Description

[0010] To more clearly illustrate the technical solutions in the embodiments of this application or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this application. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0011] Figure 1 This is a schematic diagram illustrating the position marking of the drill pipe thread axis according to an embodiment of the present invention; Figure 2 This is a schematic diagram of the circumferential position marking of the drill pipe thread according to an embodiment of the present invention. Detailed Implementation

[0012] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the scope of protection of the present invention.

[0013] This application aims to provide a CNC machine tool thread repair method that can automatically position itself within a CNC machine tool without altering the machine tool structure, while simultaneously reducing the skill level requirements for operators in thread repair operations and improving workpiece quality and processing efficiency. This embodiment proposes a thread repair method for CNC lathes, the key being the rapid and precise alignment of the CNC thread lathe helix with the helix of the thread to be repaired, including: 1. Pre-machine the thread-fitting tool, which is a calibration sample that mates with the thread of the drill pipe being repaired. The structure of the calibration sample is the same as that of a thread gauge, or a thread gauge can be used instead of the pre-made thread-fitting tool. Use the thread-fitting tool to position and determine the standard helical trajectory of the CNC lathe in the current coordinate system.

[0014] 2. Clamp the thread to be repaired on the CNC lathe, perform initial positioning using a thread fitting tool, and then fine-tune it with axial tool compensation to make the helix of the thread to be repaired coincide with the helix set on the lathe in the axial direction; achieve the coincidence of the helix of the thread to be repaired with the helix of the lathe, and ensure that the starting point of the tool in the axial direction of the thread to be repaired is precisely aligned with the starting point on the axis of the CNC thread lathe.

[0015] Using a threaded fitting tool as a reference, connect the threaded fitting tool to the thread to be repaired. Using the outer diameter and end face of the threaded fitting tool as a reference, determine the starting point in the axial direction and the starting point in the circumferential direction of the thread to be repaired, ensuring that the lathe spindle pitch corresponds to the circumferential starting point of the thread to be repaired.

[0016] Optionally, the distance from the end face of the thread-fitting tool to the lathe chuck is measured to determine the lathe's Z-axis parameters; the angle is converted based on the thread pitch, and the angle deviation is manually calculated by combining visual observation. The rotational position is then corrected using tool compensation to complete the tool setting process. Furthermore, to reduce costs, the thread-fitting tool can also be a pre-fabricated part with the same structure as the thread-fitting tool itself.

[0017] 3. Before clamping, determine the starting point in the circumferential direction by rotating the tool using the scale on the threaded tool, and tighten the chuck to complete the positioning and clamping; ensure that the recorded starting point in the circumferential direction perfectly coincides with the actual starting point through clamping.

[0018] IV. Once the two key parameters of the starting point in the axial direction and the starting point in the circumferential direction are perfectly matched, only the Z-axis parameters on the CNC lathe need to be finely adjusted to achieve thread repair.

[0019] The core of this calibration method lies in the logical closed loop of "fixing the Z-direction length → circumferential reference → fixing the starting point". By fixing the Z-direction length, the originally random clamping error is transformed into a controllable systematic deviation, thus making the starting point of the helical cut reproducible. During subsequent repairs, only this reference needs to be referred to, eliminating the need for repeated trial cuts and significantly reducing the difficulty of debugging.

[0020] This embodiment's method rapidly locks the starting point of the cutting tool in the space of the thread to be repaired after secondary clamping by precisely aligning the helix of the CNC lathe with the helix of the thread to be repaired. In practice, a thread-fitting tool is pre-machined, and the raw material is fixed to a specific length before turning. By fixing the length, the starting point of the cutting tool in the space of the CNC lathe's helix is ​​accurately determined and recorded in both the circumferential and axial directions. Next, the tapered thread product to be repaired is inserted into the spindle through-hole. Using a thread-fitting tool that matches the thread pitch of the thread to be repaired, the lathe spindle pitch is ensured to accurately correspond to the starting point of the cutting tool on the circumference of the thread to be repaired. Subsequently, by fine-tuning the tool compensation in the axial direction, the starting point of the original drill rod thread is precisely located. This method aims to reduce the dependence on operational skills for thread finishing by precisely locating the starting point of the original tapered thread after secondary clamping, significantly improving workpiece quality and processing efficiency.

[0021] Finally, it should be noted that: the accompanying drawings of the embodiments disclosed in this invention only involve structures related to the embodiments disclosed in this invention, and other structures can refer to general designs. In the absence of conflict, the same embodiment and different embodiments of this invention can be combined with each other.

[0022] In conclusion, the above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A method for repairing threads on a CNC lathe, characterized in that, include: S1. Use a threaded tool to locate and determine the standard helical trajectory of the CNC lathe in the current coordinate system; S2. Clamp the thread to be repaired on the CNC lathe, initially position it using a thread fitting tool, and then finely adjust it with axial tool compensation to make the helix of the thread to be repaired coincide with the helix set on the lathe in the axial direction; achieve the coincidence of the helix of the thread to be repaired with the helix of the lathe, and ensure that the starting point of the tool in the axial direction of the thread to be repaired is precisely aligned with the starting point on the axis of the CNC thread lathe. S3. Before clamping, determine the starting point in the circumferential direction by rotating the tool according to the scale on the threaded tool, and tighten the chuck to complete the positioning and clamping; ensure that the recorded starting point in the circumferential direction coincides perfectly with the actual starting point through clamping; S4. Once the two key parameters of the starting point in the axial direction and the starting point in the circumferential direction are perfectly matched, only the Z-axis parameters on the CNC lathe need to be finely adjusted to achieve thread repair.

2. The thread repair method for CNC lathes according to claim 1, characterized in that, Using a threaded fitting tool as a reference, connect the threaded fitting tool to the thread to be repaired. Using the outer diameter and end face of the threaded fitting tool as a reference, determine the starting point in the axial direction and the starting point in the circumferential direction of the thread to be repaired, ensuring that the lathe spindle pitch corresponds to the circumferential starting point of the thread to be repaired.

3. The thread repair method for CNC lathes according to claim 2, characterized in that, Measure the distance from the end face of the thread-fitting tool to the lathe chuck to determine the lathe Z-axis parameters; convert the angle according to the thread pitch, correct the rotational position through tool compensation, and complete the tool setting process.

4. The thread repair method for CNC lathes according to claim 1, characterized in that, The thread fitting tool is a pre-machined calibration sample that matches the thread of the drill pipe being repaired.

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