A machining method for high-precision thin-wall multi-cavity parts

Abstract

This invention discloses a machining method for high-precision thin-walled multi-cavity parts, belonging to the field of precision machining and manufacturing technology. The high-precision thin-walled multi-cavity parts have a front structure, a back structure, and a through-cavity structure penetrating both sides. The machining method includes the following steps: selecting milling equipment and clamping device; machining the total thickness of the part; machining the front structure and deburring; flipping the part and clamping it; machining the back structure and the through-cavity structure and deburring. The advantages of this invention are: it proposes a universal machining principle and designs specific machining steps for high-precision thin-walled multi-cavity parts. During the machining process, deburring is performed using milling equipment, enabling high-quality burr-free machining of high-precision thin-walled multi-cavity parts, especially suitable for aerospace-grade high-precision thin-walled multi-cavity parts.

Description

Technical Field

[0001] This invention relates to the field of precision machining and manufacturing technology, and in particular to a method for machining high-precision thin-walled multi-cavity parts. Background Technology

[0002] For high-precision machined parts used in aerospace products, such as slotted waveguide antennas, the following characteristics are typically observed: First, due to the lightweight requirements of aerospace products, aerospace parts are generally made of lightweight aluminum alloy materials, and weight reduction must be maximized while meeting usage conditions. These parts are usually characterized by thin walls and multiple cavities. For example, some large slotted waveguide antennas have many walls of about 0.8mm to 1mm, and there are a large number of cavities on both sides, sometimes numbering in the tens of thousands. Second, as a path for electrical signals, they have very complex shapes and high precision requirements. For example, the machining accuracy of waveguide cavities typically requires dimensional tolerances within ±0.03mm, surface flatness less than or equal to 0.05mm / 200×200, parallelism less than or equal to 0.1, and surface finish less than or equal to 1.6μm. Right angles in the cavities are not allowed to be chamfered, and when the finished product is observed under a 40-60x microscope, there must be no burrs inside the cavity.

[0003] Based on the above characteristics, for the machining of complex and high-precision parts, such as the high-precision requirements of the cavities in the cracked waveguide, traditional methods use CNC milling. However, traditional CNC milling produces burrs on certain right-angled edges, requiring post-processing removal. For large, high-precision cavities, burr removal is usually done manually by a fitter under a microscope, which is not only very labor-intensive but also prone to damaging precision parts, affecting electrical performance. Patent document CN109940225A discloses a burr removal device and method for the cavity of a cracked waveguide, which uses a squeezing and cutting method to remove burrs, inevitably damaging the surface of the part at the burr connection point and failing to meet the requirements of precision machining. Patent document CN210413580U discloses a waveguide antenna crack machining fixture for burr control during the machining process. This fixture applies extrusion pressure to the characteristics of the part itself, affecting the machining accuracy. Furthermore, it is designed for a specific antenna unit structure and does not form a universal machining method. Summary of the Invention

[0004] The technical problem to be solved by this invention is how to achieve burr-free machining of high-precision thin-walled multi-cavity parts.

[0005] This invention solves the above-mentioned technical problems through the following technical means: a processing method for high-precision thin-walled multi-cavity parts, wherein the high-precision thin-walled multi-cavity parts have a front structure, a back structure, and a through-cavity structure penetrating both the front and back sides, and the processing method for the high-precision thin-walled multi-cavity parts includes the following steps:

[0006] S1, Select the milling equipment and clamping device;

[0007] S2, the part blank is clamped by a clamping device and the total thickness of the part is processed by a milling machine.

[0008] S3, select one side of the design structure as the front structure, process the front structure with a milling machine, and after all the front structures are processed, deburr the front structure with a milling machine.

[0009] S4, Remove the part, flip the part over, and clamp the part using the clamping device;

[0010] S5. The reverse structure is processed by milling equipment. After the reverse structure is fully processed, the through cavity structure is processed. After the through cavity structure is fully processed, the reverse structure and the through cavity structure are deburred by milling equipment.

[0011] This invention proposes a general processing principle and designs specific processing steps for the machining of high-precision thin-walled multi-cavity parts. During the machining process, milling equipment is used to remove burrs, which can achieve high-quality burr-free machining of high-precision thin-walled multi-cavity parts, and is especially suitable for aerospace high-precision thin-walled multi-cavity parts.

[0012] Preferably, in step S1, a CNC milling machine with a rotational speed greater than or equal to 18,000 rpm is selected as the milling equipment. The higher the rotational speed of the CNC milling machine, the better the surface quality of the part while keeping the cutting depth constant. A CNC milling machine with a rotational speed greater than or equal to 18,000 rpm can process parts that meet the design requirements.

[0013] Preferably, in S1, an adsorption clamping device is selected as the clamping device. For high-precision thin-walled multi-cavity parts, the adsorption clamping device can effectively clamp the parts without affecting the machining accuracy of the parts and without damaging the surface of the parts.

[0014] Preferably, in S1, the suction force of the adsorption clamping device is greater than or equal to the milling force, which is calculated by the following formula:

[0015]

[0016] Where F is the milling force, in N; c F a is the milling force coefficient; p This refers to the milling depth, in mm; af feed per tooth; a e d0 is the milling width; d0 is the milling cutter diameter in mm; z is the number of milling cutter teeth; k F This is a correction factor.

[0017] Preferably, in S2, when processing the total thickness of the part, the thickness allowance is evenly distributed on both sides of the part blank, the layer cutting depth is 0.05 to 0.2 mm, and the part is processed by repeatedly turning the two sides over for finishing.

[0018] Preferably, in step S4, after the part is removed, the tooling blank is clamped on the clamping device, and the adsorption tooling is processed by a milling machine. After the adsorption tooling is processed, it remains on the clamping device. The part is flipped over so that the front structure of the part matches the machined surface of the adsorption tooling, and the part is clamped by the clamping device.

[0019] Preferably, in step S5, the machining process of the through-cavity structure is carried out in two steps. The first step is to machine the entire through-cavity structure to a certain depth, leaving a margin. The second step is to mill the entire through-cavity structure. Before milling the through-cavity structure, there are no gaps between the adsorption tooling and the parts, eliminating the risk of air leakage and ensuring the adsorption effect.

[0020] Preferably, in step S5, a part fixing device is provided to assist in clamping the part. This prevents the risk of air leakage after the cavity structure is milled through, further ensuring the adsorption effect.

[0021] Preferably, in S3 and S5, the processing method for the front structure, the back structure and the through cavity structure is rough machining followed by fine machining, with a fine machining allowance left after rough machining, and the depth of cut of the last cut in fine machining being less than or equal to 0.02mm.

[0022] Preferably, in S3 and S5, the deburring method for both the front and back structures is to have the milling cutter make one pass along the bottom surface of all structures, and the deburring method for the through-cavity structure is to have the milling cutter process a certain distance further along the depth direction of the through-cavity structure.

[0023] The advantages of this invention are as follows: This invention proposes a universal processing principle and designs specific processing steps for the processing of high-precision thin-walled multi-cavity parts. During the processing, milling equipment is used to remove burrs, which can achieve high-quality burr-free processing of high-precision thin-walled multi-cavity parts, and is especially suitable for aerospace high-precision thin-walled multi-cavity parts. Attached Figure Description

[0024] Figure 1 This is a schematic diagram of the front structure and through-cavity structure of the high-precision thin-walled multi-cavity part targeted in the embodiments of the present invention.

[0025] Figure 2This is a schematic diagram of the reverse side structure and through-cavity structure of the high-precision thin-walled multi-cavity part targeted in the embodiments of the present invention.

[0026] Figure 3 This is a flowchart of a processing method for high-precision thin-walled multi-cavity parts according to an embodiment of the present invention. Detailed Implementation

[0027] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the embodiments of the present invention. Obviously, the described embodiments are only some embodiments of the present invention, not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the protection scope of the present invention.

[0028] like Figure 1 , Figure 2 As shown, the high-precision thin-walled multi-cavity part targeted by the present invention has a front structure 1, a back structure 2, and a through-cavity structure 3 that runs through both the front and back.

[0029] These components primarily utilize raw materials such as aluminum alloys and magnesium alloys, which are significantly "softer" than steel in terms of strength and rigidity. Structurally, they are characterized by large, flat, thin-plate structures with substantial length and width dimensions; for example, a single layer of a millimeter-wave antenna measures 800mm x 800mm. However, their thickness is relatively small, typically less than 10mm. The front structure 1 includes a front thin-walled structure 11 and a front cavity structure 12. The wall thickness of the front thin-walled structure 11 is typically 0.8mm to 1mm. Multiple front cavity structures 12 are formed between the front thin-walled structures 11, and various front boss structures can be incorporated within each front cavity structure 12. The reverse structure 2 includes a reverse thin-walled structure 21 and a reverse cavity structure 22, which have similar structural forms to the front thin-walled structure 11 and the front cavity structure 12. Various reverse boss structures 23 can also be incorporated within the reverse cavity structure 22. The two ends of the through-cavity structure 3 are located within the front cavity structure 12 and the reverse cavity structure 22, respectively. The front structure 1 and the back structure 2 are basically the same, but some structures can be added or removed. The front boss structure, the back boss structure 23 and the through cavity structure 3 usually have tens of thousands of structures, and the structure is very complex.

[0030] The machining accuracy requirements for the high-precision thin-walled multi-cavity parts are as follows: all dimensional tolerances are within ±0.02mm, the flatness of the top and bottom surfaces of the concave cavities is less than or equal to 0.05mm / 100×100, the overall surface finish is less than or equal to 1.6μm, and no burrs are allowed inside the cavities when observed under a 40-60x microscope after machining.

[0031] like Figure 3As shown in the figure, an embodiment of the present invention discloses a method for processing high-precision thin-walled multi-cavity parts, including the following steps:

[0032] S1, Select the milling equipment and clamping device.

[0033] In this embodiment, a CNC milling machine with a rotational speed of 18,000 rpm or higher is selected as the milling machining equipment. CNC milling machines are widely used in modern manufacturing and can produce parts with high complexity and precision. The higher the rotational speed of the CNC milling machine, the better the surface quality of the part while maintaining a constant depth of cut. A CNC milling machine with a rotational speed of 18,000 rpm or higher can machine parts that meet the design requirements.

[0034] For high-precision, thin-walled, multi-cavity parts, clamping with devices such as pressure plates is difficult due to their thin walls and lack of effective clamping edges. Furthermore, when the parts are large, pressure plates can only clamp the periphery, leaving the center unsecured, affecting machining accuracy. On the other hand, improper operation of clamping devices like pressure plates can damage the part's surface. Therefore, this embodiment selects an adsorption-type clamping device, which can effectively clamp the parts without affecting machining accuracy and without damaging the part's surface.

[0035] The suction force of the adsorption clamping device is greater than or equal to the milling force, which is calculated using the following formula:

[0036]

[0037] Where F is the milling force, in N; c F a is the milling force coefficient; [ This refers to the milling depth, in mm; a f feed per tooth; a e d0 is the milling width; d0 is the milling cutter diameter in mm; z is the number of milling cutter teeth; k F This is a correction factor.

[0038] To avoid errors caused by using different processing equipment during the processing, which could affect the processing accuracy of the parts, the same CNC milling machine and adsorption clamping device are used for processing in the following steps S2 to S5.

[0039] S2, the part blank is clamped by an adsorption clamping device, and the total thickness of the part is machined by a CNC milling machine, specifically including the following steps:

[0040] 2.1 Before machining, clean the worktable and other parts that will come into contact with the parts during machining, such as the CNC milling machine's worktable.

[0041] 2.2 After cleaning, the part blank is clamped on the worktable of the CNC milling machine using an adsorption clamping device. The clamping method is side top clamping.

[0042] 2.3. Distribute the thickness allowance evenly on both sides of the part blank. In order to reduce deformation, use a small cutting amount during processing, with a layer cutting depth of 0.05 to 0.2 mm. Use a method of repeatedly flipping the two sides for finishing.

[0043] S3, select one of the design structures as the front structure 1, process the front structure 1 by CNC milling machine, after all the front structure 1 is processed, deburr the front structure 1 by CNC milling machine.

[0044] 3.1 The simpler side of the design structure is selected as the front structure 1. The reason is that when flipping and clamping in the subsequent step S4, the end face of the adsorption fixture needs to be processed according to the shape of the front structure 1. The simpler front structure 1 can simplify the design and processing of the adsorption fixture, reduce the clamping difficulty, improve processing efficiency and quality, and reduce processing costs.

[0045] 3.2 The machining method for the front structure 1 is to first rough and then finish. After rough machining, a 0.1mm finishing allowance is left. The finishing is carried out using a multi-step, small-cutting strategy, and the depth of cut of the last cut is less than or equal to 0.02mm.

[0046] 3.3 The method for deburring the front structure 1 is as follows: the milling cutter moves along the bottom surface of all structures on the front side in one pass, and the cutter is not allowed to be lifted when moving along structures at the same height.

[0047] S4, remove the part, clean it, and set it aside for later use; clamp the tooling blank on the adsorption clamping device, and process the adsorption tooling by CNC milling machine. After the adsorption tooling is processed, leave it on the adsorption clamping device; flip the part so that the front structure 1 of the part mates with the machined surface of the adsorption tooling, and clamp the part by the adsorption clamping device; before flipping and clamping, clean the machined surfaces of the front structure 1 and the adsorption tooling, and at the same time check the burr status of the front structure 1 to ensure that there are no debris, burrs, or other foreign objects on the mating surfaces; after flipping and clamping, use the same datum as the front machining for alignment.

[0048] S5, the reverse structure 2 is machined by CNC milling machine. After the reverse structure 2 is fully machined, the through cavity structure 3 is machined. After the through cavity structure 3 is fully machined, the reverse structure 2 and the through cavity structure 3 are deburred by CNC milling machine.

[0049] 5.1 To ensure the adsorption effect of the adsorption clamping device throughout the entire processing, the through-cavity structure 3 is left to be processed last. The processing of the through-cavity structure 3 is carried out in two steps. In the first step, the through-cavity structure 3 is processed to a certain depth, leaving a 0.1mm allowance without milling through. In the second step, the through-cavity structure 3 is milled through. Using this method, there are no gaps between the adsorption fixture and the part before the through-cavity structure 3 is milled through, so there is no risk of air leakage and the adsorption effect is guaranteed.

[0050] 5.2 In addition, to prevent the risk of air leakage after milling the through cavity structure 3, a part fixing device is set up to assist in clamping the part. Before machining the through cavity structure 3, the effectiveness of the part fixing device is confirmed to prevent accidents during the machining process. The part fixing device can be a pressure plate, which is overlapped between the part edge with sufficient margin and the adsorption fixture to achieve fixation. The part fixing device can also be a screw, which utilizes a suitable through cavity position on the part and sets a threaded hole at the corresponding position on the adsorption fixture, and fixes the part to the adsorption fixture with screws. Multiple part fixing devices can be used in combination to achieve auxiliary clamping. The auxiliary clamping points are distributed as evenly as possible on the part while considering the available positions of the part.

[0051] 5.3 The machining method for both the reverse structure 2 and the through cavity structure 3 is rough machining followed by finish machining. After rough machining, a 0.1mm finish machining allowance is left. The finish machining adopts a multi-step, small-cutting strategy, and the depth of cut of the last cut is less than or equal to 0.02mm.

[0052] 5.4 The method for deburring the reverse structure 2 is as follows: the milling cutter moves along the bottom surface of all structures on the reverse side in one pass, and the cutter is not allowed to be lifted when moving along the structure at the same height.

[0053] 5.5 The method for deburring the through cavity structure 3 is as follows: the milling cutter processes an additional 0.02mm along the depth direction of the through cavity structure 3 to remove the burrs at the opening of the through cavity.

[0054] 5.6 After all the front structure 1, back structure 2 and through cavity structure 3 are processed, disassemble, clean and dry the surface of the parts, and place them in the packaging box for storage and transit.

[0055] The above embodiments are only used to illustrate the technical solutions of the present invention, and are not intended to limit it. Although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some of the technical features. Such modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims

1. A method for machining high-precision thin-walled multi-cavity parts, characterized in that: The high-precision thin-walled multi-cavity part has a front structure, a back structure, and a through-cavity structure that penetrates both sides. The front structure includes a front thin-walled structure and a front cavity structure. The wall thickness of the front thin-walled structure is 0.8mm to 1mm, and the dimensional tolerance is required to be within ±0.02mm. The processing method of the high-precision thin-walled multi-cavity part includes the following steps: S1, Select the milling equipment and clamping device; S2, the part blank is clamped by the clamping device, the thickness allowance is evenly distributed on both sides of the part blank, and the total thickness of the part is processed by milling equipment with a layer cutting depth of 0.05~0.2mm and the two sides are repeatedly flipped to finish. S3. Select the side with the simpler design structure as the front structure. Use a milling machine to rough and then finish the front structure. Leave a finishing allowance after roughing. The last cut depth of the finishing cut is ≤0.02mm. After all the front structures are machined, use a milling machine to run one cut along the bottom surface of all the front structures to remove burrs. Do not lift the cutter when running the cutter along the structure at the same height. S4, remove the parts and clean them. Clamp the tooling blank on the clamping device to process the adsorption tooling. After the adsorption tooling is processed, leave it on the clamping device. Turn the parts over so that the front structure of the parts matches the processing surface of the adsorption tooling. Clamp the parts through the clamping device and use the same reference as the front processing to align them. S5, the reverse structure is first roughed and then finished using a milling machine. After roughing, a finishing allowance is left. The final cut depth of the finishing is ≤0.02mm. After all the reverse structures are finished, the through-cavity structure is processed in two steps. The first step is to process all the through-cavities to a certain depth and leave a allowance. The second step is to mill through all the through-cavities. After all the through-cavities are finished, the milling machine is used to run one pass along the bottom surface of all the reverse structures to remove burrs from the reverse structures and through-cavities. An additional 0.02mm is machined along the depth direction of the through-cavities to remove burrs from the through-cavities.

2. The method for machining high-precision thin-walled multi-cavity parts as described in claim 1, characterized in that: In S1, a CNC milling machine with a speed greater than or equal to 18,000 rpm is selected as the milling machining equipment.

3. The method for machining high-precision thin-walled multi-cavity parts as described in claim 1, characterized in that: In S1, an adsorption clamping device is selected as the clamping device.

4. The method for machining high-precision thin-walled multi-cavity parts as described in claim 3, characterized in that: In S1, the suction force of the adsorption clamping device is greater than or equal to the milling force, which is calculated using the following formula: ； Where F is the milling force, and the unit is 1000 kJ / m³. ; This is the milling force coefficient; The milling depth is expressed in units of 1 / 200 mm. ; This refers to the feed per tooth. This refers to the milling width; The diameter of the milling cutter is given in units of 1000 mm. ; This refers to the number of teeth on the milling cutter. This is a correction factor.

5. The method for machining high-precision thin-walled multi-cavity parts as described in claim 1, characterized in that: In S5, a part fixing device is set up to assist in clamping the part.

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