A machining method of a precision k-type metal sealing ring

Abstract

The application discloses a machining method of a precise K-shaped metal sealing ring, which comprises the following steps: clamping the bottom of a columnar blank by a precise numerical control lathe; turning the columnar blank into a ring-shaped blank; machining the outer shape allowance of the ring-shaped blank; turning the ring-shaped blank with the rough-machined outer shape allowance into a V-shaped hole by using a K-shaped surface forming tool; turning the ring-shaped blank with the V-shaped hole into a center hole by using the K-shaped surface forming tool; turning off the bottom of the columnar blank; and removing burrs to obtain the precise K-shaped metal sealing ring. The application has the advantages of high machining efficiency, high qualified rate and good economy.

Description

Technical Field

[0001] This invention belongs to the field of machining technology for precision parts for rocket engines, and particularly relates to a machining method for a precision K-type metal sealing ring. Background Technology

[0002] K-shaped sealing rings possess self-tightening sealing properties, effectively sealing under conditions of temperature and pressure fluctuations, and are therefore widely used in liquid oxygen / kerosene rocket engine piping systems. The K-shaped sealing ring is made of GH4169 high-temperature alloy bar, a difficult-to-machine material. It has a thin-walled ring structure with a maximum outer diameter of approximately Φ30mm. Its cross-section is "K"-shaped, with a wall thickness of less than 0.8mm at each protruding clamping position. The depth of the cavity between the two clamping positions is approximately 4mm, but the narrowest point is less than 0.3mm. All tolerances for the sealing parts are extremely stringent, with a minimum tolerance of only 0.006mm, and the surface roughness of all sealing positions must be better than Ra0.8.

[0003] The traditional machining process for K-shaped sealing rings involves first roughing by turning the outer diameter and drilling the inner hole. Then, in a precision machining environment, the inner hole is semi-finished and finished using a precision CNC machine tool. After the inner surface is formed, the outer surface is finished and cut off. The limited machining space inside the product results in a small boring bar diameter, which is prone to vibration during machining. Furthermore, due to the high hardness and viscosity of the material, the tool tip wears severely during machining, making it difficult to maintain stable control over dimensional accuracy and surface roughness during finish machining.

[0004] In the past, a lot of time was usually spent on precise alignment during the machining process, and methods such as reducing the feed rate, increasing the number of feeds, and frequent tool changes were used to ensure the machining accuracy of the K-shaped sealing ring parts. This seriously suppressed the machining efficiency. Even so, the qualified rate of the machined products was low, which was difficult to meet the production pace of the increasingly large batch processing of rocket engines. Summary of the Invention

[0005] The technical problem solved by this invention is to overcome the shortcomings of the prior art and provide a machining method for a precision K-type metal sealing ring, which has the advantages of high machining efficiency, high pass rate and good economy.

[0006] The objective of this invention is achieved through the following technical solution: a method for machining a precision K-type metal sealing ring, comprising: clamping the bottom of a cylindrical blank on a precision CNC lathe; turning the cylindrical blank into a ring-shaped blank; machining the outer shape allowance of the ring-shaped blank; using a K-type face forming cutter to machine a V-shaped hole in the ring-shaped blank after rough machining of the outer shape allowance; using a K-type face forming cutter to machine a center hole in the ring-shaped blank after machining the V-shaped hole; removing the bottom of the cylindrical blank; and removing burrs to obtain a precision K-type metal sealing ring.

[0007] In the above-mentioned machining method of precision K-type metal sealing ring, the bottom of the cylindrical blank is clamped by the hydraulic three-jaw self-centering chuck of a precision CNC lathe. The cylindrical blank is a high-temperature alloy GH4169, and the clamping force of the hydraulic three-jaw self-centering chuck is 2Pa-3Pa.

[0008] In the above-mentioned machining method for precision K-type metal sealing rings, a boring tool is used to turn the cylindrical blank into a ring-shaped blank; wherein, the boring tool is a square insert with R0.4mm and a tip radius of 93°, and the boring tool rotates at 700r / min.

[0009] The above-mentioned machining method for a precision K-type metal sealing ring includes a cutting edge and a cutting body; wherein the cutting edge and the cutting body are connected; and the geometry of the cutting edge is completely consistent with the inner shape of the K-type surface of the sealing ring.

[0010] In the above-mentioned machining method for precision K-type metal sealing rings, the rake angle of the K-type surface forming cutter is 5°, the clearance angle of the K-type surface forming cutter is 15°, and the principal cutting edge angle of the K-type surface forming cutter is 25°.

[0011] In the above-mentioned machining method of precision K-type metal sealing ring, the process of machining a V-shaped hole from the ring-shaped blank after rough machining of the outer shape allowance using a K-type surface forming cutter includes: obtaining the tool movement trajectory according to the position of the V-shaped hole, and machining the V-shaped hole according to the tool movement trajectory using the K-type surface forming cutter.

[0012] In the above-mentioned machining method for precision K-type metal sealing rings, when machining the V-shaped hole with the K-type face forming tool, the rotation speed is 200 r / min and the feed rate is 0.01 mm / min. After machining is completed, the tool is paused for 10 seconds and then exited along the original path of the tool movement trajectory at a speed of 1.1 mm / min.

[0013] In the above-mentioned machining method of precision K-type metal sealing ring, the process of machining the center hole of the annular blank after machining the V-shaped hole using a K-type surface forming cutter includes: obtaining the tool movement trajectory according to the position of the center hole, and machining the center hole according to the tool movement trajectory using the K-type surface forming cutter.

[0014] In the above-mentioned machining method for precision K-type metal sealing rings, when machining the center hole with a K-type surface forming tool, the rotation speed is 200 r / min and the feed rate is 0.01 mm / min. After machining, the tool is paused for 10 seconds and then exited along the original path of the tool movement trajectory at a speed of 1.1 mm / min.

[0015] In the above-mentioned machining method for precision K-type metal sealing rings, a cutting-off tool is used to machine off the bottom of the cylindrical blank; wherein, the cutting-off tool is an external groove tool with a blade width of 1.5mm; during roughing, the rotation speed is 400r / min, the feed rate is 0.05mm / min, and the depth of cut is 1mm; during finishing, the rotation speed is 600r / min, and the feed rate is 0.03mm / min.

[0016] Compared with the prior art, the present invention has the following advantages: (1) The present invention can achieve micron-level machining accuracy in conventional machining environments, and compared with precision machining conditions, it has high machining efficiency and good economy; (2) The present invention uses a three-jaw self-centering chuck on a precision CNC lathe for one-time clamping, and only five steps are required to complete the machining. The process is simple and the machining efficiency is significantly improved. (3) The present invention independently designed and matched special tool for precision machining of K-type surface. The larger front and rear angles can reduce tool wear. The tool tip and tool steel body are connected by brazing, which significantly improves tool rigidity and improves machining dimension consistency. Attached Figure Description

[0017] Various other advantages and benefits will become apparent to those skilled in the art upon reading the following detailed description of preferred embodiments. The accompanying drawings are for illustrative purposes only and are not intended to limit the invention. Furthermore, the same reference numerals denote the same parts throughout the drawings. In the drawings: Figure 1 This is a cross-sectional view of the precision K-type metal sealing ring provided in an embodiment of the present invention; Figure 2(a) is a schematic diagram of the precision K-type metal sealing ring provided in an embodiment of the present invention; Figure 2(b) is another schematic diagram of the precision K-type metal sealing ring provided in an embodiment of the present invention; Figure 3(a) is a schematic diagram of the K-type surface forming tool provided in an embodiment of the present invention; Figure 3(b) is a cross-sectional view of the Pr view in Figure 3(a) provided in an embodiment of the present invention; Figure 3(c) is a cross-sectional view of the Po view in Figure 3(a) provided in an embodiment of the present invention; Figure 4 This is a schematic diagram of the blade tip provided in an embodiment of the present invention; Figure 5 This is another schematic diagram of the blade tip provided in an embodiment of the present invention; Figure 6 This is a flowchart of the processing method for a precision K-type metal sealing ring provided in an embodiment of the present invention. Detailed Implementation

[0018] Exemplary embodiments of the present disclosure will now be described in more detail with reference to the accompanying drawings. While exemplary embodiments of the present disclosure are shown in the drawings, it should be understood that the present disclosure may be implemented in various forms and should not be limited to the embodiments set forth herein. Rather, these embodiments are provided to enable a more thorough understanding of the present disclosure and to fully convey the scope of the disclosure to those skilled in the art. It should be noted that, unless otherwise specified, the embodiments and features described herein can be combined with each other. The present invention will now be described in detail with reference to the accompanying drawings and embodiments.

[0019] Figure 6 This is a flowchart of a processing method for a precision K-type metal sealing ring provided in an embodiment of the present invention. Figure 6 As shown, this embodiment provides a method for machining a precision K-type metal sealing ring, the method comprising: (1) The bottom of the cylindrical blank is clamped by a precision CNC lathe; wherein the cross-section of the cylindrical blank is rectangular; (2) Turn the columnar blank into a ring-shaped blank; it should be understood that this step is to cut off the middle part of the columnar blank in step (1); (3) Machining the outer shape allowance of the ring-shaped blank; it should be understood that this step is to... Figure 1 The blank material above the upper boundary line in the K-shaped section is machined off. (4) Using a K-type face forming tool, V-shaped holes are machined into the annular blank after rough machining of the outer shape allowance; wherein, the V-shaped hole is Figure 1 As shown; (5) Using a K-type face forming cutter, the annular blank after the V-shaped hole is machined to form the center hole; wherein, the center hole is Figure 1 As shown; (6) Remove the bottom of the columnar blank; it should be understood that the bottom of the columnar blank that is removed is the part clamped by the precision CNC lathe. (7) Remove burrs to obtain a precision K-type metal sealing ring.

[0020] This embodiment offers advantages such as high processing efficiency and stable micron-level quality precision control in conventional environments. Compared to the traditional machining process that combines turning the outer diameter with precision boring, it achieves better processing quality and consistency. The cutting edge of the special tool is ground to a specific rake angle and inclination angle, which, combined with the machining method, enables the batch processing of precision K-type metal sealing rings. This solves the micron-level machining problem of the inner surface in conventional machining environments and effectively ensures surface roughness, resulting in significant effects in mass production.

[0021] Figure 2(a) is a schematic diagram of the precision K-type metal sealing ring provided in an embodiment of the present invention; Figure 2(b) is another schematic diagram of the precision K-type metal sealing ring provided in an embodiment of the present invention. As shown in Figures 2(a) and 2(b), the K-type metal sealing ring is a thin-walled annular rotary structure. The wall thickness of the two overhanging legs of the "K" type is only about 0.6 mm. During the machining process, the deformation is very easy to exceed the tolerance due to the cutting force.

[0022] In step (1), the bottom of the cylindrical blank is clamped by the hydraulic three-jaw self-centering chuck of a precision CNC lathe. The cylindrical blank is a high-temperature alloy GH4169, and the clamping force of the hydraulic three-jaw self-centering chuck is 2Pa-3Pa. Specifically, the clamping force is 2.5Pa. During the clamping process, a copper sheet with a thickness of 0.1mm and a width of 25mm is placed on the circumference of the blank. During processing, only the length of one part product is suspended at a time.

[0023] In step (2), a boring bar is used to turn the cylindrical blank into a ring-shaped blank; the boring bar is a square insert with a radius of 0.4mm and a tip radius of 93°, and the boring bar rotates at 700 r / min. Using a 93° boring bar, the inner and outer surfaces are machined on a lathe to form a stepped rotating body. The purpose is twofold: firstly, to remove a large amount of blank material; and secondly, to achieve a better cylindricity of the machined surface, which can serve as a reference for subsequent machining.

[0024] In step (3), an external turning tool is used to machine the external allowance of the annular blank; wherein, the external turning tool is a square insert with a radius of 0.4mm and a tip radius of 93°, and the rotation speed of the external turning tool is 700r / min. The external allowance of the part is machined using a 93° external turning tool. In this way, the easier-to-machine external surface is machined in one go, so that the external shape directly reaches the final size.

[0025] Figures 3(a), 3(b), and 3(c) Figure 4 and Figure 5 As shown, the K-type face forming tool includes a cutting edge and a tool body. The carbide cutting edge is brazed to the tool body, and its geometry perfectly matches the inner shape of the K-type face of the sealing ring. The rake angle of the carbide cutting edge... ( The angle between the rake face and the base plane is 5°, and the tool clearance angle is... ( The angle between the principal flank and the cutting plane is 15°, and the principal cutting edge angle is... ( The angle between the projection of the main cutting edge and the feed direction is 25°.

[0026] A dedicated K-shaped surface forming tool is used to precisely machine the K-shaped surface in one pass with low speed and small feed. A forming tool is used, first utilizing the cutting points A and B of the tool tip (e.g., ...). Figure 4 and Figure 5 (As shown). Using the inner hole and right end face already machined in the first step as coordinate references, establish workpiece coordinate systems on the inner hole and end face of the part respectively (in order to convert machine tool coordinates into workpiece coordinates). At this time, a conversion relationship is established between the workpiece coordinate system and the machine tool coordinate system. Then, using CAD software, the virtual coordinates of the workpiece coordinate system are converted to the machine tool coordinate system, and the motion trajectory of the forming tool can be calculated. The actual tool can ensure that the V-groove on the inner shape is formed in one go by machining along this path.

[0027] The left inner surface is roughed and finished to dimensional accuracy using an internal grooving cutter in one pass. Then, the inner hole is machined step-by-step using an internal grooving cutter inside the workpiece until the final dimension is reached.

[0028] The left side of the outer surface is cut off using a cutting blade for both rough and fine machining. Starting from the root of the product on the outer surface, the blade moves from the outside in until the product is removed from the chuck.

[0029] Remove the burrs and flanging from the cut surface manually.

[0030] In step (4), the process of machining a V-shaped hole in the annular blank after rough machining of the outer shape allowance using a K-shaped surface forming cutter includes: obtaining the tool movement trajectory based on the position of the V-shaped hole, and machining the V-shaped hole using the K-shaped surface forming cutter based on the tool movement trajectory.

[0031] In step (4), when machining the V-shaped hole with the K-type surface forming tool, the rotation speed is 200 r / min and the feed rate is 0.01 mm / min. After machining, pause for 10 seconds and then exit along the original path of the tool movement trajectory at a speed of 1.1 mm / min.

[0032] In step (5), the process of machining the center hole of the annular blank after machining the V-shaped hole using a K-shaped forming cutter includes: obtaining the tool movement trajectory based on the position of the center hole, and machining the center hole using the K-shaped forming cutter based on the tool movement trajectory.

[0033] In step (5), when machining the center hole with the K-type surface forming tool, the rotation speed is 200 r / min and the feed rate is 0.01 mm / min. After machining, pause for 10 seconds and then exit along the original path of the tool movement trajectory at a speed of 1.1 mm / min.

[0034] First, use the tangent points A and B of the K-type face forming tool tip to establish the workpiece coordinates on the inner hole and cross-section of the part, respectively. Then, use CAD software to calculate the motion trajectory of the forming tool based on the virtual coordinates of the working coordinate system. Using cutting parameters of spindle speed of 200 r / min and feed rate of 0.01 mm / min with cutting fluid, machine to the theoretical coordinate point, pause for 10 seconds, and exit along the original path of the feed trajectory at a speed of 1.1 mm / min.

[0035] In step (6), the bottom of the columnar blank is machined off using a cutting cutter; wherein the cutting cutter is an external groove cutter with a blade width of 1.5 mm; the speed during roughing is 400 r / min, the feed rate is 0.05 mm / min, and the depth of cut is 1 mm; the speed during finishing is 600 r / min, and the feed rate is 0.03 mm / min.

[0036] Specifically, a standard external grooving CNC tool with a blade width of 1.5mm is used. During roughing, the spindle speed is 400r / min, the feed rate is 0.05mm / min, and the depth of cut is 1mm. The cutting parameters are reserved for finishing with a 0.15mm allowance. During finishing, the spindle speed is 600r / min and the feed rate is 0.03mm / min to achieve the final dimensional accuracy while cutting off the part.

[0037] This embodiment achieves micron-level machining accuracy in conventional machining environments, offering higher machining efficiency and better economy compared to precision machining conditions. This embodiment utilizes a three-jaw self-centering chuck on a precision CNC lathe for single-clamping, requiring only five steps to complete the machining process, simplifying operations and significantly improving efficiency. The main design of this embodiment includes a dedicated precision machining tool for K-shaped surfaces. Its larger rake and camber angles reduce tool wear, and the brazing connection between the tool tip and the tool steel body significantly improves tool rigidity and dimensional consistency. This embodiment designs the cutting edge angle of the K-shaped surface forming tool to +3°, effectively controlling chip flow towards the machined surface, ensuring no damage to the machined surface, and simultaneously improving the surface finish and dimensional accuracy of the parts, thus effectively increasing the yield rate.

[0038] Although the present invention has been disclosed above with reference to preferred embodiments, it is not intended to limit the present invention. Any person skilled in the art can make possible changes and modifications to the technical solutions of the present invention by utilizing the methods and techniques disclosed above without departing from the spirit and scope of the present invention. Therefore, any simple modifications, equivalent changes and alterations made to the above embodiments based on the technical essence of the present invention without departing from the content of the technical solutions of the present invention shall fall within the protection scope of the technical solutions of the present invention.

Claims

1. A method for machining a precision K-type metal sealing ring, characterized in that... include: The bottom of the cylindrical blank is clamped using a precision CNC lathe; The columnar blank is machined into a ring-shaped blank; The allowance for machining the shape of the ring-shaped blank; A K-type face forming tool is used to machine a V-shaped hole into the ring-shaped blank after rough machining of the outer shape; The center hole is machined from the annular blank after the V-shaped hole is machined using a K-type surface forming cutter. The bottom of the columnar blank is machined off; Remove the burrs to obtain a precision K-type metal sealing ring.

2. The machining method of the precision K-type metal sealing ring according to claim 1, characterized in that: The bottom of the cylindrical blank is clamped by a hydraulic three-jaw self-centering chuck on a precision CNC lathe. The cylindrical blank is made of high-temperature alloy GH4169, and the clamping force of the hydraulic three-jaw self-centering chuck is 2Pa-3Pa.

3. The machining method of the precision K-type metal sealing ring according to claim 1, characterized in that: A boring tool is used to turn a cylindrical blank into a ring-shaped blank; the boring tool is a square insert with a radius of 0.4 mm and a tip radius of 93°, and the boring tool rotates at 700 r / min.

4. The machining method of the precision K-type metal sealing ring according to claim 1, characterized in that: The K-type surface forming tool includes a cutting edge and a tool body; wherein... The blade and the blade body are connected; The geometry of the blade is completely consistent with the inner shape of the K-shaped surface of the sealing ring.

5. The machining method of the precision K-type metal sealing ring according to claim 4, characterized in that: The front angle of the K-shaped surface forming cutter is 5°, the rear angle of the K-shaped surface forming cutter is 15°, and the principal cutting edge angle of the K-shaped surface forming cutter is 25°.

6. The machining method of the precision K-type metal sealing ring according to claim 1, characterized in that: Using a K-type face forming tool to machine a V-shaped hole in the annular blank after rough machining of the outer shape allowance includes: The tool movement trajectory is obtained based on the position of the V-shaped hole, and the K-shaped surface forming tool processes the V-shaped hole according to the tool movement trajectory.

7. The method for machining a precision K-type metal sealing ring according to claim 6, characterized in that: When machining V-shaped holes with a K-type face forming tool, the rotation speed is 200 r / min and the feed rate is 0.01 mm / min. After machining, pause for 10 seconds and then exit along the original path of the tool movement trajectory at a speed of 1.1 mm / min.

8. The method for machining a precision K-type metal sealing ring according to claim 1, characterized in that: Using a K-type face forming tool to machine the center hole of the annular blank after machining the V-shaped hole includes: The tool movement trajectory is obtained based on the position of the center hole, and the K-type surface forming tool processes the center hole according to the tool movement trajectory.

9. The method for machining a precision K-type metal sealing ring according to claim 8, characterized in that: When machining the center hole with a K-type surface forming tool, the rotation speed is 200 r / min and the feed rate is 0.01 mm / min. After machining, pause for 10 seconds and then exit along the original path of the tool movement trajectory at a speed of 1.1 mm / min.

10. The method for machining a precision K-type metal sealing ring according to claim 1, characterized in that: The bottom of the cylindrical blank is machined off using a cut-off tool; the cut-off tool is an external grooving tool with a blade width of 1.5 mm; the roughing speed is 400 r / min, the feed rate is 0.05 mm / min, and the depth of cut is 1 mm; the finishing speed is 600 r / min and the feed rate is 0.03 mm / min.

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