A drill-mill-forming combined tool for cutting and end forming of tubular parts and a machining method thereof
By designing a composite tool that integrates drilling, milling, and forming functions, the problems of frequent tool changes and difficult positioning in the processing of tubular parts were solved, enabling efficient and stable cutting and end forming of high-strength materials in deep-water environments.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- JIANGSU TIANGONG CEMENTED CARBIDE TECH CO LTD
- Filing Date
- 2026-04-28
- Publication Date
- 2026-07-17
AI Technical Summary
Existing technologies for processing tubular components suffer from problems such as numerous tool changes, multiple positioning steps, low operating efficiency, and poor processing consistency, especially in deep-water environments and high-strength materials, making it difficult to meet the requirements for rapid cutting and end forming.
Design a composite tool that integrates drilling, milling, and forming on a single tool. It adopts an integral structure, including a drilling section, a milling section, and a forming section. It is equipped with a forward spiral blade and a burr shearing microgroove. It is made of M35 high-speed steel and coated with a wear-resistant and corrosion-resistant coating to ensure that the tool works efficiently and stably in deep water environments.
It significantly reduces the number of tool changes and repositioning, improves machining efficiency and consistency, enhances cutting sharpness and chip removal, adapts to the deep-water machining requirements of thick-walled tubular parts, and meets the machining quality requirements of high-strength materials.
Smart Images
Figure CN122400624A_ABST
Abstract
Description
Technical Field
[0001] This invention relates to the field of cutting tools for machining tubular components, and in particular to a drilling-milling-forming composite tool and its machining method for cutting and shaping tubular components. Background Technology
[0002] In applications such as marine oil and gas transportation, deep-water pipeline maintenance, and the manufacturing, maintenance, and repair of other tubular components, it is often necessary to quickly cut tubular components and then shape their ends to meet the requirements of subsequent welding, connection, assembly, or repair operations. Traditional methods typically involve using multiple tools to complete drilling, cutting, and end-shaping in steps. This not only results in numerous tool changes and positioning steps but also, in deep-water environments or confined working spaces, limitations in driving capacity and corrosion resistance can lead to low efficiency, difficulties in tool alignment, and poor machining consistency.
[0003] Especially for tubular components made of high-strength materials such as pipeline steel with strength of API 5L X65 and above, if the workpiece has a large outer diameter and thick wall, existing step-by-step processes struggle to balance cutting efficiency, tool life, and end-face contour accuracy. Therefore, it is necessary to provide a composite tool that integrates drilling, milling, and end-forming functions on the same tool to reduce tool changes and repetitive positioning, thereby improving machining efficiency and quality. Summary of the Invention
[0004] To address the aforementioned problems in the prior art, this invention provides a drilling-milling-forming composite tool and its processing method for cutting and shaping tubular components. By integrating the drilling section, milling and cutting section, and shaping section into one unit, the tool can sequentially complete the workpiece drilling, workpiece milling, and end shaping in a single clamping state, thereby improving processing efficiency and consistency.
[0005] To achieve the above objectives, the present invention adopts the following technical solution: The composite tool includes a tool body and a tool shank connected to the tool body. The tool body includes, along the axial direction, a drilling section, a milling and cutting section, and a forming section. The drilling section is used to drill through the workpiece along the wall thickness direction of the tubular component. The milling and cutting section is used to mill along the circumference of the tubular component after drilling to cut off the workpiece. The forming section is used to perform contour forming on the end of the workpiece. The outer circumference of the milling and cutting section is provided with a positive helical cutting edge, and the circumferential cutting edge is provided with burr shearing microgrooves to improve cutting sharpness, chip breaking ability, chip removal ability, and surface finish. The length of the tool shank is greater than the wall thickness of the tubular component to be processed to ensure that the tool still has sufficient connection and guiding length after penetrating the wall thickness.
[0006] As a further preferred embodiment, the composite tool adopts an integrated design, with the drilling section, milling and cutting section, and shaping section forming a whole with the tool holder; the tool body adopts a three-flute structure, with each flute evenly distributed circumferentially, and the included angle between adjacent flutes is 120°. A drill tip is set at the front end, a helical milling edge is formed in the middle, and a shaping edge is formed near the tool holder, so as to take into account the drilling ability, cutting efficiency, and end contour replication ability.
[0007] As a further preferred embodiment, the forming processing unit adopts a contouring cutting edge that matches the target end profile. Taking a U-shaped outer bevel as an example, the contour of the contouring cutting edge is consistent with the contour of the U-shaped outer bevel to be formed; when it is necessary to process an inner bevel or a combined inner and outer bevel, it is only necessary to adjust the cutting edge of the forming processing unit to a profile consistent with the corresponding target end profile, and implement it according to the same drilling, cutting and contouring forming principles.
[0008] As a further preferred embodiment, the tool body is made of M35 high-speed steel, or M35 high-speed steel prepared by powder metallurgy; the hardness after heat treatment is 64HRC~66HRC. The surface of the tool body is coated with a uniform and dense wear-resistant and corrosion-resistant coating, the coating adhesion is greater than 70N, and the corrosion resistance meets the requirements of a 48h neutral salt spray test, so as to meet the continuous operation requirements in marine environments or other corrosion-resistant working conditions.
[0009] As a further preferred embodiment, the overall coaxiality tolerance of the composite tool is controlled within 0.02 mm, and the deviation between the end contour and the target end contour is controlled within ±0.1 mm; unspecified dimensional tolerances are performed according to GB / T1804-m grade, with sharp edges blunted by 0.3×45° and transition fillets of R1±0.2. According to the trial production and usage requirements, before the tool wear reaches the wear criterion specified in ISO16460:2016, the tool can complete at least 5 drill penetrations, at least 5 milling cuts, and at least 5 end forming operations.
[0010] Compared with existing split-type cutting tools, the present invention has at least the following beneficial effects: First, by integrating drilling, cutting, and end forming into a single tool, the number of tool changes and repeated alignments can be significantly reduced; Second, by setting the forward helical blade and the peripheral burr shearing microgroove, the cutting sharpness and chip removal effect can be improved, thereby enhancing the surface quality of the machined parts; Third, by setting the tool holder length to be greater than the wall thickness of the tubular parts, and combining it with corrosion-resistant and wear-resistant materials and coating design, it can better adapt to the processing requirements of deep-water scenarios and thick-walled tubular parts. Attached Figure Description
[0011] To more clearly illustrate the technical solution of the present invention, the accompanying drawings are briefly described below. Obviously, the drawings described below are only some embodiments of the present invention, and those skilled in the art can obtain other drawings based on these drawings without creative effort.
[0012] Figure 1 This is a schematic diagram of the cutting and end forming process for tubular components. Figure 2 A schematic diagram of the target end profile parameters; Figure 3 This is a schematic diagram of a composite tool design scheme; Figure 4 This is a schematic diagram of the overall structure and cross-sectional position of the composite tool; Figure 5 for Figure 4 Schematic diagram of section AA; Figure 6 for Figure 4 Schematic diagram of the BB section; Figure 7 for Figure 4 Schematic diagram of the CC section. Detailed Implementation
[0013] To make the objectives, technical solutions, and advantages of this invention clearer, the invention will be further described in detail below with reference to the accompanying drawings and specific embodiments. It should be understood that the specific embodiments described herein are for illustrative purposes only and are not intended to limit the invention.
[0014] Unless otherwise defined, the technical or scientific terms used in this invention shall have the ordinary meaning understood by one of ordinary skill in the art to which this invention pertains. The terms "first," "second," etc., used in this invention are used only to distinguish different components and do not indicate any order, quantity, or importance; the terms "comprising" or "including" mean that the preceding element covers the following element and its equivalents, without excluding the presence of other elements.
[0015] I. Composite Tool Structure This composite tool adopts an integral structure, mainly composed of a front-end drilling section, a middle milling and cutting section, a shaping section, and a rear-end tool holder. Along the tool axis from the front end to the rear end, the components are sequentially arranged as follows: the drilling section, the milling and cutting section, the shaping section, and the tool holder. The front-end drilling section is used to initially establish a through-cutting channel in the wall thickness direction of the tubular component; the middle milling and cutting section is used to complete continuous milling and cutting as the tool moves circumferentially around the tubular component; the shaping section is designed with a contour corresponding to the target end profile, used for shaping the end after the workpiece is cut. The tool body preferably has a three-flute structure, with three cutting edges evenly distributed circumferentially, and adjacent edges having an included angle of 120°; the milling and cutting section forms a positive helical cutting edge, with burr shearing microgrooves on its circumferential edge to facilitate chip separation and removal and improve cutting edge sharpness. (See attached reference.) Figure 3 , Figure 4 , Figure 5 , Figure 6 and Figure 7 .
[0016] II. Dimensions and Outline Reference Appendix Figure 2 , Figures 4-7 According to the engineering and process drawings, the cutting tool can be machined from a blank bar with an outer diameter of 22mm and a length of 160mm. After forming, the diameter of the tool holder connecting section is approximately 20mm, and the diameter of the front drilling section is approximately 12mm. The engineering drawings provide example dimensions such as front-end local lengths of 5mm, 15mm, and 47.18mm, and a total working length of 100mm, as well as transition radii such as R1 and R3.18, and local angle parameters such as 13°, 3°, 35°, 9°, 10°, and 12°. These dimensions and angles define the preferred structural form to ensure the transition relationship and machining stability between the drill tip, spiral cutting edge, and contour forming edge. For different tubular component sizes and wall thicknesses, adaptive adjustments can be made without altering the drilling, cutting, and contour machining principles of this invention.
[0017] III. Materials and Properties Reference Appendix Figures 3-7 The tool body is preferably made of M35 high-speed steel, but powder metallurgy M35 high-speed steel blanks can also be used; the hardness after heat treatment is controlled at 64HRC~66HRC. To meet the corrosion resistance and service life requirements in marine environments or other corrosion-resistant working conditions, a uniform and dense wear-resistant and corrosion-resistant coating can be applied to the surface of the tool body. The coating adhesion is greater than 70N and passes a 48h neutral salt spray test. The overall coaxiality tolerance of the tool is controlled within 0.02mm, and the end contour deviation is controlled within ±0.1mm.
[0018] IV. Applicable workpieces and processing requirements Reference Appendix Figure 1 and Figure 2This composite cutting tool is suitable for tubular components made of materials such as pipeline steel with a strength of API 5L X65 and above. When machining pipes, the maximum outer diameter can be 330 mm and the maximum wall thickness can be 34.3 mm. When the tool is driven by a hydraulic motor, the driving speed does not exceed 2000 rpm. The machining accuracy can reach IT8 to IT7, and the surface roughness can reach 6.3 to 1.6 μm. Within the wear criterion range specified in ISO 16460:2016, the tool can complete at least 5 penetrations, at least 5 millings, and at least 5 end forming operations.
[0019] V. Processing Method Reference Appendix Figure 1 When using this composite tool for cutting and end forming of tubular components, the tool is first moved to the designated cutting position on the tubular component. Then, driven by a hydraulic motor, the tool rotates and feeds radially along the tubular component, using the front drilling section to drill through the workpiece. After drilling, the tool is kept rotating, causing the milling cutting section to rotate one or two revolutions around the tubular component, thus achieving milling. After cutting, the forming section performs contour forming on the end of the workpiece. For external bevel machining scenarios, end forming can be performed separately after circumferential milling, or it can be integrated into the circumferential cutting step and completed continuously by adjusting the relative axial position of the tool and the workpiece end and the radial feed rate. Example
[0020] Reference Appendix Figures 1-7 Taking the forming of a U-shaped outer bevel end as an example, an integral three-flute composite tool made of M35 high-speed steel or powder metallurgy M35 high-speed steel is selected. The diameter of the tool shank connecting section is approximately 20mm, the diameter of the front drilling section is approximately 12mm, and the tool shank length is greater than 34.3mm. During operation, a hydraulic motor is used for drive, with a speed not exceeding 2000rpm. The tool first feeds radially along the tubular component to drill through the wall thickness, then moves circumferentially around the tubular component to complete the milling. Finally, the forming edge replicates the U-shaped bevel contour, thereby forming the target outer bevel at the end of the workpiece. This method reduces the number of tool changes and repeated positioning, which helps ensure the consistency of the end contour and the quality of the end face.
[0021] Reference Appendix Figure 1 , Figure 3 and Figure 4For machining internal bevels or composite internal and external bevels, the same integrated composite tool structure and machining steps can still be used; the only difference is that the contour of the forming cutting edge is designed according to the contour of the internal bevel or composite internal and external bevel to be formed. The tool first establishes a through-cutting channel through the drilling section, then completes circumferential milling through the milling section, and finally completes end forming with the contour of the forming edge corresponding to the target end contour. Since its working principle is the same as that of the U-shaped external bevel embodiment, those skilled in the art can directly design the corresponding contour of the forming edge and perform machining based on the target end contour.
[0022] The above description is merely a preferred embodiment of the present invention and is not intended to limit the scope of protection of the present invention. Any equivalent substitutions, improvements, and modifications made within the spirit and principles of the present invention shall fall within the scope of protection of the present invention.
Claims
1. A drilling-milling-forming composite tool for cutting and end forming of tubular components, characterized in that, The tool includes a tool body and a tool holder connected to the tool body. The tool body includes, along the axial direction, a drilling section, a milling and cutting section, and a forming section. The drilling section is used to drill through the workpiece along the wall thickness direction of the tubular part to be processed. The milling and cutting section is used to mill along the circumferential direction of the tubular part to be processed after drilling to cut off the workpiece. The forming section is configured with a contour cutting edge corresponding to the profile of the end to be processed, and is used to perform forming processing on the end of the workpiece after it is cut off. The length of the tool holder is greater than the wall thickness of the tubular part to be processed.
2. The composite cutting tool according to claim 1, characterized in that, The drilling section, milling and cutting section, forming section and tool holder are integrated into a single structure to achieve continuous completion of drilling, milling and cutting and end forming.
3. The composite cutting tool according to claim 1 or 2, characterized in that, The blade has a three-blade structure, with each blade evenly distributed along the circumference of the blade, and the circumferential angle between adjacent blades is 120°.
4. The composite cutting tool according to claim 1, characterized in that, The milling cutting section is provided with a positive helical blade on its outer periphery, and a burr shearing micro-groove is provided on the peripheral blade to improve cutting sharpness, chip breaking ability and chip removal ability.
5. The composite cutting tool according to claim 1, characterized in that, The forming process is a contouring blade that matches the target end profile; when the target end profile is a U-shaped outer bevel, the forming process is a U-shaped outer bevel contouring blade; when the target end profile is an inner bevel or a combination of inner and outer bevels, the forming process is a contouring blade that matches the corresponding target end profile.
6. The composite cutting tool according to claim 1, characterized in that, The tool body is made of M35 high-speed steel or powder metallurgy M35 high-speed steel, and the hardness after heat treatment is 64HRC~66HRC; the surface of the tool body is provided with a wear-resistant and corrosion-resistant coating, the coating has an adhesion force greater than 70N, and can pass a 48h neutral salt spray test.
7. The composite cutting tool according to claim 1, characterized in that, The overall coaxiality tolerance of the composite tool is less than 0.02 mm, and the deviation between the end contour formed by the forming part and the target end contour is ±0.1 mm; the unspecified dimensional tolerances shall be in accordance with GB / T1804-m grade, the sharp edge shall be blunted by 0.3×45°, and the transition fillet shall be R1±0.
2.
8. A method for cutting and end forming tubular components using the composite tool described in any one of claims 1 to 7, characterized in that, Includes the following steps: S1. Move the composite tool to the designated cutting position on the tubular component; S2. Drive the composite tool to rotate and feed radially along the tubular component, so that the drilling part drills through the workpiece; S3. While keeping the compound tool rotating, rotate the milling cutting part around the tubular component one or two times in the circumferential direction to complete the workpiece milling. S4. Use the forming processing unit to perform imitation forming processing on the end of the workpiece to form the target end contour.
9. The processing method according to claim 8, characterized in that, The forming process in step S4 is achieved by adjusting the relative axial position and / or radial feed of the composite tool and the end of the workpiece; when necessary, step S4 can be combined with step S3 to continuously complete the end forming process during the circumferential cutting of the workpiece.
10. The processing method according to claim 8 or 9, characterized in that, The workpiece to be processed is a tubular component of pipeline steel with strength of API 5L X65 or above; when the tubular component is a pipe, the maximum outer diameter of the pipe to be processed is 330mm and the maximum wall thickness is 34.3mm; the composite tool is suitable for deep-water operation scenarios driven by a hydraulic motor, with a driving speed not exceeding 2000rpm; before the tool wear reaches the wear criterion specified in ISO 16460:2016, the composite tool can complete at least 5 drilling passes, at least 5 milling passes, and at least 5 end forming operations.