Aluminum alloy polygonal thin-walled part cutting process method

Abstract

This invention discloses a machining process for aluminum alloy polygonal thin-walled parts, comprising the following steps: blanking an aluminum alloy sheet using a horizontal band saw; machining the blank from step 2 using a CNC lathe to obtain a thin-walled part and a connecting column, machining a threaded hole in the middle of the thin-walled part and an external threaded section at one end of the connecting column; milling the target structure of the polygonal thin-walled part using a CNC milling machine according to the dimensions of the target structure; precision machining the target structure using a CNC lathe, controlling the CNC lathe tool to reverse the machining process to obtain the finished aluminum alloy polygonal thin-walled part. This invention effectively addresses the structural characteristics of polygonal irregular thin-walled parts, reducing machining deformation, improving machining efficiency, employing a clamping method combining specialized fixture design and general-purpose fixtures, using argon arc welding of the blank structure, and providing a process method that meets the needs of multi-process machining of polygonal irregular thin-walled parts.

Description

Technical Field

[0001] This invention relates to a machining process for thin-walled polygonal aluminum alloy parts, belonging to the field of machining technology. Background Technology

[0002] Aluminum alloys possess excellent mechanical properties, electrical conductivity, corrosion resistance, and thermal conductivity, making them widely used in aerospace, shipbuilding, medical machinery, and precision machinery. However, during metal cutting, thin-walled aluminum alloy parts suffer from low rigidity, high material removal rates, and poor machinability. Influenced by cutting forces, cutting heat, and cutting vibrations, these parts can experience significant deformation, making it difficult to meet dimensional accuracy requirements. This paper analyzes an aluminum alloy polygonal thin-walled part with a wall thickness of 1.6±0.05mm, coaxiality Φ0.05mm, flatness 0.05mm, and parallelism 0.05mm. High dimensional accuracy and geometric tolerances are required, making tool deflection a common problem during machining. Furthermore, the part's structural characteristics result in a high material removal rate, leading to low efficiency in machining parts from a single piece.

[0003] Currently, Chinese invention patent CN 111730114 A discloses a milling method for thin-walled aluminum alloy web structure components, including cyclic heat treatment to release residual stress in the workpiece and prevent overheating deformation during milling. However, for the machining of certain polygonal and irregular thin-walled parts, multiple component torsion operations are involved, and the reference conversion is cumbersome. Using this method alone is difficult to meet the machining requirements.

[0004] Therefore, given the shortcomings of existing processes, developing an effective process for controlling the deformation during the machining of thin-walled polygonal aluminum alloy parts is the key to solving the aforementioned technical problems. Summary of the Invention

[0005] In view of the many defects and deficiencies existing in the above-mentioned background technology, the present invention has made improvements and innovations, aiming to provide an effective process method for processing polygonal irregular thin-walled parts, taking into account the structural characteristics of the parts, reducing processing deformation, improving processing efficiency, and reducing processing costs. This method adopts a clamping method that combines special fixture design with general fixtures, argon arc welding of blank structure, and multiple aging treatments, etc., to meet the needs of multi-process processing of polygonal irregular thin-walled parts.

[0006] Another objective of this invention is to ensure the dimensional accuracy of parts, improve processing efficiency, reduce processing costs, and increase the processing qualification rate.

[0007] To solve the above problems and achieve the above-mentioned objectives, the present invention provides a machining process for aluminum alloy polygonal thin-walled parts by adopting the following design structure and the following technical solution:

[0008] A machining process for thin-walled polygonal aluminum alloy parts includes the following steps:

[0009] Step 1: Blank aluminum alloy sheets are cut using a horizontal band saw.

[0010] Step 2: Eliminate the residual internal stress in the blank plate from Step 1;

[0011] Step 3: The blank in Step 2 is processed by a CNC lathe to obtain a thin-walled part (1) and a connecting column (2), with an overall allowance of 2mm to 2.5mm. The thin-walled part screw hole is machined in the middle of the thin-walled part (1) and the external thread section of the connecting column (2) is machined at one end.

[0012] Step 4: Screw the threaded end of the connecting post (2) into the threaded hole of the thin-walled part, and weld the connecting end of the connecting post (2) and the thin-walled part (1) to form the shape structure of the polygonal thin-walled workpiece (3);

[0013] Step 5: Eliminate the residual internal stress in the shape structure of the polygonal thin-walled workpiece (3) from Step 4;

[0014] Step 6: Roughly machine the outer contour and inner cavity of the polygonal thin-walled workpiece (3) using a CNC lathe, leaving an overall allowance of 0.8mm to 1.2mm;

[0015] Step 7: Eliminate the residual internal stress on the polygonal thin-walled workpiece (3) that was rough-machined in Step 6;

[0016] Step 8: The outer contour and inner cavity of the polygonal thin-walled workpiece (3) are machined by semi-finish turning on a CNC lathe, with an overall allowance of 0.3mm to 0.5mm.

[0017] Step 9: Eliminate the residual internal stress on the semi-finished polygonal thin-walled workpiece (3) from Step 8;

[0018] Step 10: Mill the target structure of the polygonal thin-walled workpiece (3) using a CNC milling machine according to the dimensions of the target structure;

[0019] Step 11: The target structure is precision machined using a CNC lathe to a depth of 0.1 mm.

[0020] Step 12: Control the CNC lathe tool (7) to turn around and perform machining, while ensuring that all dimensional tolerances and geometric tolerances meet the dimensions of the target structural drawing. After machining, an aluminum alloy polygonal thin-walled finished part (9) is obtained.

[0021] Preferably, in the machining process of step 3, the CNC lathe clamps the outer circular surfaces of the thin-walled part (1) and the connecting column (2) using a three-jaw self-centering chuck, and aligns the outer circle using a lever dial indicator to ensure that the runout is less than 0.3mm. The CNC lathe uses a YG8 carbide cutting tool (7) to machine the threaded hole of the thin-walled part and the external thread section of the connecting column, respectively, with a cutting speed of 25m / min, a feed rate of 1.2mm / r, and a depth of cut of 1mm. The overall allowance for the outer contour dimensions of the thin-walled part (1) and the connecting column (2) is 2mm to 2.5mm to eliminate the influence of the deformation generated during the welding process in the next step on the semi-finishing and finishing processes.

[0022] Preferably, the polygonal thin-walled workpiece (3) in step 4 includes:

[0023] A thin-walled part (1) is fixedly connected to the middle of the thin-walled part (1), and a screw hole for the thin-walled part is opened in the middle of the non-fixed end of the fixing part (11).

[0024] The connecting column (2) has an external thread section (21) at one end of its body that is compatible with the internal thread of the thin-walled part, and a square column (22) is connected to the other end of its body. The square column (22) also has a through hole.

[0025] Among them, the non-fixed end of the fastener (11) is provided with a fastener circumferential welding part that is easy to weld, and the connection end of the connecting column body and the connecting column external thread section (21) is provided with a connecting column body circumferential welding part that is easy to weld with the fastener circumferential welding part.

[0026] Preferably, in the welding process of step 4, argon arc welding is used for welding, and the weld seam is a V-type welding method. The circumferential welding part of the fastener and the circumferential welding part of the connecting column body are welded and fixed together, thereby welding the thin-walled part (1) and the connecting column (2) into the shape structure of the polygonal thin-walled workpiece (3).

[0027] Preferably, in the machining process of step 6, the CNC lathe clamps the outer surface of the thin-walled part (1) of the polygonal thin-walled workpiece (3) with a three-jaw self-centering chuck, aligns the outer circle with a lever dial indicator to ensure that the runout is less than 0.5mm, and uses a carbide YG8 cutting tool (7) for machining. The cutting speed is 25m / min, the feed rate is 1.2mm / r, and the depth of cut is 1mm. The large end face of one side of the thin-walled part (1) is rough-turned until it is smooth, and the inner cavity surface and inner groove are bored. Then, the lathe turns around, the inner cavity surface of the polygonal thin-walled workpiece (3) is supported by the three-jaw self-centering chuck, and the outer circle is aligned with a lever dial indicator to ensure that the runout is less than 0.5mm. The outer contour and step surface of one side of the thin-walled part (1) are rough-turned, and the outer contour of the connecting cylindrical side is also rough-turned.

[0028] Preferably, in the machining process of step 8, a CNC lathe is used to clamp the outer surface of the thin-walled part (1) of the polygonal thin-walled workpiece (3) with a three-jaw self-centering chuck. The outer circle is aligned by a lever dial indicator to ensure that the runout is less than 0.1 mm. A carbide YG8 cutting tool (7) is selected for machining. The cutting speed is 40 m / min, the feed rate is 0.7 mm / r, and the depth of cut is 0.9 mm. The large end face of one side of the thin-walled part (1) is semi-finished until it is smooth, and the inner cavity surface and inner groove are bored. The lathe is turned around, and the inner cavity surface of the polygonal thin-walled workpiece (3) is supported by the three-jaw self-centering chuck. The outer circle is aligned by a lever dial indicator to ensure that the runout is less than 0.1 mm. The outer contour and step surface of one side of the thin-walled part (1) are rough-machined, and the outer contour of the connecting cylindrical side is also rough-machined.

[0029] Preferably, in the processing of step 10, according to the size of the target structure, a CNC milling machine is used to clamp the inner cavity structure of the polygonal thin-walled workpiece (3) with a three-jaw self-centering chuck that is matched with it. The outer circle is then aligned by a lever dial indicator, with a runout of less than 0.02 mm. The target structure is then machined using a carbide end mill. During the machining process, a high-grade water-soluble cutting fluid (Sakura Kaken S-12) is used to reduce the cutting temperature. The spindle speed is 8500 r / min, the cutting depth is 1 mm, and the cutting parameters are 0.05 mm.

[0030] The target structure is to mill a 10-sided profile, a flat-bottomed hole, and several fastening holes on the non-connecting column end of the thin-walled part (1), wherein the fastening holes penetrate the front and back of the thin-walled part (1); and to mill a square small step structure and an inner hole on the connecting column end of the thin-walled part (1).

[0031] Preferably, in step 11, the boss of the first fixture (4) is first tightly fitted to the inner cavity of the polygonal thin-walled workpiece (3). Then, four sets of fastening screws (6) are passed through the fastening holes on the polygonal thin-walled workpiece (3) to fix the polygonal thin-walled workpiece (3) to the first fixture (4) together, while ensuring coaxiality Φ0.05mm. Then, the other end of the first fixture (4) is clamped and firmly connected by a four-jaw chuck (5) connected to the CNC lathe for precision turning. During precision machining, the outer circle is aligned by a lever dial indicator, and the runout of the large end face is less than 0.02mm. Machining is performed by a turning tool (7) made of cemented carbide YG8 material. During machining, high-grade water-soluble cutting fluid (Sakura Kaken S-12) is used to reduce the cutting temperature. The cutting speed is 45m / min, the feed rate is 0.1mm / r, and the depth of cut is 0.05mm.

[0032] Preferably, in step 12, the inner hole of the second clamp (8) is first tightly connected to the connecting column (2), and at the same time, the thin wall surface of the large end of the polygonal thin-walled workpiece (3) is flat against the end face of the second clamp (8). Then, four sets of fastening screws (6) are passed through the fastening holes on the polygonal thin-walled workpiece (3) to fix the polygonal thin-walled workpiece (3) and the second clamp (8) together, while ensuring coaxiality Φ0.05mm. Then, the other end of the step surface of the second fixture (8) is clamped by the four-jaw chuck (5) connected to the CNC lathe for precision turning; during machining, the outer circle is aligned by lever dial indicator to ensure that the runout of the end face is less than 0.02mm. Machining is performed by a carbide YG8 cutting tool (7). During machining, high-grade water-soluble cutting fluid (Sakura Kaken S-12) is used to reduce the cutting temperature. The cutting speed is 45m / min, the feed rate is 0.1mm / r, and the depth of cut is 0.05mm.

[0033] Preferably, in step 2, eliminating the residual internal stress of the blank in step 1 is achieved by placing the blank at room temperature into an artificial aging furnace, heating it to 185 to 195 degrees Celsius, maintaining it for 6 to 8 hours, and then cooling it to room temperature with the furnace after the heat treatment is completed.

[0034] In step 5, the residual internal stress of the polygonal thin-walled workpiece (3) in step 4 is eliminated by placing the aluminum alloy polygonal thin-walled workpiece (3) at room temperature into an artificial aging furnace, heating it to 220 degrees Celsius, holding it for 6 hours, and then cooling it to room temperature with the furnace after the heat treatment is completed.

[0035] In step 7, the residual internal stress on the rough-machined polygonal thin-walled workpiece (3) in step 6 is eliminated by placing the rough-machined polygonal thin-walled workpiece (3) at room temperature into an artificial aging furnace, heating it to 220 degrees Celsius, maintaining it for 6 hours, and then cooling it to room temperature with the furnace after the heat preservation is completed.

[0036] In step 9, the residual internal stress on the semi-finished polygonal thin-walled workpiece (3) in step 8 is eliminated by placing the semi-finished polygonal thin-walled workpiece (3) at room temperature into an artificial aging furnace, heating it to 220 degrees Celsius, maintaining it for 6 hours, and then cooling it to room temperature with the furnace after the heat preservation is completed.

[0037] The beneficial effects of this invention compared to the prior art are:

[0038] 1. This invention completes the processing of thin-walled aluminum alloy parts by means of process methods, rough turning of the outer shape and inner cavity, using welding to reduce material removal rate and processing amount, artificial aging, semi-finish turning, finish turning of inner cavity and boss, and milling polygons, ensuring the dimensional accuracy of the parts, improving processing efficiency, reducing processing costs, and improving the processing qualification rate.

[0039] 2. This invention considers the weak overall rigidity of aluminum alloy polygonal thin-walled parts and adopts the principle of process concentration in the process route design to reduce datum conversion. Heat treatment is performed in both the roughing and semi-finishing stages, and cutting parameters are optimized. Considering multiple aspects such as reducing the deformation of thin-walled parts, improving processing efficiency, and reducing processing costs, a clamping method combining special fixtures and general fixtures is designed, along with argon arc welding of the blank structure and multiple aging treatments. This process method meets the requirements of multi-process machining of polygonal irregular thin-walled parts, effectively controlling the deformation of the parts and ensuring machining accuracy. At the same time, the material removal rate of thin-walled parts is relatively high. Welding is adopted according to the characteristics of the parts, which can effectively reduce the amount of machining, improve processing efficiency, and significantly improve the pass rate. Attached Figure Description

[0040] The specific embodiments of the present invention will be further described in detail below with reference to the accompanying drawings, wherein:

[0041] Figure 1 This is one of the usage state diagrams of the present invention;

[0042] Figure 2 This is the second usage state diagram of the present invention;

[0043] Figure 3 This is the third usage state diagram of the present invention;

[0044] Figure 4 This is an exploded structural diagram of the polygonal thin-walled workpiece (3) of the present invention;

[0045] Figure 5 This is a cross-sectional schematic diagram of the polygonal thin-walled workpiece (3) of the present invention;

[0046] Figure 6 This is a schematic diagram of the structure of the first clamp (4) component of the present invention;

[0047] Figure 7 This is a plan view of the first clamp (4) component of the present invention;

[0048] Figure 8 This is the present invention. Figure 7 A sectional view along the AA direction;

[0049] Figure 9 This is a schematic diagram of the structure of the second clamp (8) component of the present invention;

[0050] Figure 10 This is a plan view of the second clamp (8) component of the present invention;

[0051] Figure 11 This is the present invention. Figure 10 Cross-sectional view along the BB direction;

[0052] Figure 12 This is one of the structural schematic diagrams of the polygonal thin-walled finished part (9) of the present invention;

[0053] Figure 13 This is the second structural schematic diagram of the polygonal thin-walled finished part (9) of the present invention;

[0054] Figure 14 This is a top view of the polygonal thin-walled finished part (9) of the present invention;

[0055] Figure 15 This is the present invention. Figure 14 Sectional view in the CC direction;

[0056] Figure 16 This is one of the schematic cross-sectional views of the polygonal thin-walled finished part (9) of the present invention;

[0057] Figure 17 This is the second schematic cross-sectional view of the polygonal thin-walled finished part (9) of the present invention;

[0058] Figure 18 This is the third schematic cross-sectional view of the polygonal thin-walled finished part (9) of the present invention;

[0059] Figure 19 This is one of the planar schematic diagrams of the polygonal thin-walled finished part (9) of the present invention;

[0060] Figure 20 This is a second planar schematic diagram of the polygonal thin-walled finished part (9) of the present invention;

[0061] In the figure, the numbers are as follows: 1—thin-walled part, 11—fixed part, 2—connecting column, 21—external thread section of connecting column, 22—square column, 3—polygonal thin-walled part to be processed, 4—first fixture, 5—four-jaw chuck, 6—fastening screw, 7—lathe tool, 8—second fixture, 9—polygonal thin-walled finished part. Detailed Implementation

[0062] To make the technical means, inventive features, objectives, and effects of this invention readily understandable, the technical solution of this invention will be further described in detail below with reference to the accompanying drawings and specific embodiments. It should be noted that, unless otherwise specified, the embodiments and features described in these embodiments can be combined with each other. The invention will now be described in detail with reference to the accompanying drawings and embodiments.

[0063] A machining process for a thin-walled polygonal aluminum alloy part, as shown in the attached diagram, includes the following steps:

[0064] Step 1: Blank aluminum alloy sheets are cut using a horizontal band saw.

[0065] Step 2: Eliminate the residual internal stress in the blank plate from Step 1;

[0066] Step 3: The blank from Step 2 is machined using a CNC lathe to obtain thin-walled part 1 and connecting column 2, with an overall allowance of 2mm to 2.5mm. A threaded hole for thin-walled part 1 is machined in the middle of thin-walled part 1 and an external threaded section for connecting column 2 is machined at one end.

[0067] Step 4: Screw the threaded end of the connecting post 2 into the threaded hole of the thin-walled part, and weld the connecting end of the connecting post 2 and the thin-walled part 1 to form the shape structure of the polygonal thin-walled workpiece 3.

[0068] Step 5: Eliminate the residual internal stress in the shape structure of the polygonal thin-walled workpiece 3 from Step 4;

[0069] Step 6: Roughly machine the outer contour and inner cavity of the polygonal thin-walled workpiece 3 using a CNC lathe, leaving an overall allowance of 0.8mm to 1.2mm;

[0070] Step 7: Eliminate the residual internal stress on the polygonal thin-walled workpiece 3 that was rough-machined in Step 6;

[0071] Step 8: The outer contour and inner cavity of the polygonal thin-walled workpiece 3 are machined by semi-finish turning on a CNC lathe, with an overall allowance of 0.3mm to 0.5mm.

[0072] Step 9: Eliminate the residual internal stress on the semi-finished polygonal thin-walled workpiece 3 from Step 8;

[0073] Step 10: Mill the target structure of the polygonal thin-walled workpiece 3 using a CNC milling machine according to the dimensions of the target structure;

[0074] Step 11: The target structure is precision machined using a CNC lathe to a depth of 0.1 mm.

[0075] Step 12: Control the CNC lathe's precision turning tool 7 to perform turning machining, while ensuring that all dimensional tolerances and geometric tolerances meet the dimensions of the target structural drawing. After machining, the aluminum alloy polygonal thin-walled finished part 9 is obtained.

[0076] Furthermore, in step 3, the CNC lathe clamps the outer surfaces of the thin-walled part 1 and the connecting column 2 using a three-jaw self-centering chuck, and uses a lever dial indicator to align the outer circles, ensuring that the runout is less than 0.3mm. Using a CNC program, a YG8 carbide cutting tool 7 is selected to machine the threaded holes of the thin-walled part and the external thread section of the connecting column, respectively. The cutting speed is 25m / min, the feed rate is 1.2mm / r, and the depth of cut is 1mm. The overall allowance for the outer contour dimensions of the thin-walled part 1 and the connecting column 2 is 2mm to 2.5mm, eliminating the influence of deformation generated during the welding process in the next step on the semi-finishing and finishing processes.

[0077] Furthermore, the polygonal thin-walled workpiece 3 to be processed in step 4 includes:

[0078] Thin-walled part 1, a fastener 11 is fixedly connected to the middle of the thin-walled part 1, and a threaded hole for the thin-walled part is opened in the middle of the non-fixed end of the fastener 11.

[0079] The connecting column 2 has an external thread section 21 at one end of its body that is adapted to the internal thread of the thin-walled part, and a square column 22 is connected to the other end of its body. The square column 22 also has a through hole.

[0080] The non-fixed end of the fastener 11 is provided with a fastener circumferential welding part that is easy to weld, and the connection end of the connecting column body and the connecting column external thread section 21 is provided with a connecting column body circumferential welding part that is easy to weld with the fastener circumferential welding part.

[0081] In this invention, the connecting column body is cylindrical in shape.

[0082] Furthermore, in the welding process of step 4, argon arc welding is used for welding, and the weld seam is a V-shaped welding method. The circumferential welding part of the fastener and the circumferential welding part of the connecting column body are welded and fixed together, thereby welding the thin-walled part 1 and the connecting column 2 into the shape structure of the polygonal thin-walled workpiece 3.

[0083] In this invention, the external threaded section 21 of the connecting column is first screwed into the threaded hole of the thin-walled part, and then V-shaped welding is performed by argon arc welding, which can ensure the welding quality. At the same time, compared with processing the blank as a whole, this structure can effectively reduce the amount of processing and improve the processing efficiency.

[0084] Furthermore, in step 6, the CNC lathe clamps the outer surface of the thin-walled part 1 of the polygonal thin-walled workpiece 3 with a three-jaw self-centering chuck. The outer circle is aligned with a lever dial indicator to ensure that the runout is less than 0.5mm. A YG8 carbide cutting tool 7 is used for machining at a cutting speed of 25m / min, a feed rate of 1.2mm / r, and a depth of cut of 1mm. The large end face of one side of the thin-walled part 1 is rough-turned until it is smooth, and the inner cavity surface and inner groove are bored. The lathe is then turned around, and the inner cavity surface of the polygonal thin-walled workpiece 3 is supported by the three-jaw self-centering chuck. The outer circle is aligned with a lever dial indicator to ensure that the runout is less than 0.5mm. The outer contour and stepped surface of one side of the thin-walled part 1 are rough-turned, and the outer contour of the connecting cylindrical side is also rough-turned.

[0085] Furthermore, in step 8, during the machining process, a CNC lathe uses a three-jaw self-centering chuck to hold the outer surface of the thin-walled part 1 of the polygonal thin-walled workpiece 3. The outer circle is aligned using a lever dial indicator to ensure that the runout is less than 0.1mm. A YG8 carbide cutting tool 7 is used for machining at a cutting speed of 40m / min, a feed rate of 0.7mm / r, and a depth of cut of 0.9mm. The large end face of one side of the thin-walled part 1 is semi-finished until it is smooth, and the inner cavity surface and inner groove are bored. The lathe is then turned around, and the inner cavity surface of the polygonal thin-walled workpiece 3 is supported by the three-jaw self-centering chuck. The outer circle is aligned using a lever dial indicator to ensure that the runout is less than 0.1mm. The outer contour and stepped surface of one side of the thin-walled part 1 are rough-machined, and the outer contour of the connecting cylindrical side is also rough-machined.

[0086] Furthermore, in the machining process of step 10, according to the dimensions of the target structure, a CNC milling machine is used to clamp the polygonal thin-walled workpiece 3 internal cavity structure by using a three-jaw self-centering chuck to complete the work. The outer circle is then aligned using a lever dial indicator, with a runout of less than 0.02 mm. A carbide end mill is then used to machine the target structure. During machining, a high-grade water-soluble cutting fluid, Sakura Kaken S-12, is used to reduce the cutting temperature. The spindle speed is 8500 r / min, the cutting depth is 1 mm, and the cutting parameters are 0.05 mm.

[0087] The target structure is to mill a 10-sided profile, a flat-bottomed hole, and several fastening holes on the non-connecting column end of the thin-walled part 1, wherein the fastening holes penetrate through the front and back of the thin-walled part 1; and to mill a square small step structure and an inner hole on the connecting column end of the thin-walled part 1.

[0088] In this invention, the diameters at both ends of the fastening hole are larger than the diameter of the middle section.

[0089] Furthermore, in step 11, during the machining process, the boss of the first fixture 4 is first tightly fitted to the inner cavity of the polygonal thin-walled workpiece 3. Then, four sets of fastening screws 6 are passed through the fastening holes on the polygonal thin-walled workpiece 3 to fix the polygonal thin-walled workpiece 3 to the first fixture 4, while ensuring coaxiality Φ0.05mm. Then, the other end of the first fixture 4 is clamped and securely connected by a four-jaw chuck 5 connected to the CNC lathe for precision turning. During the finishing process, the outer circle is aligned using a lever dial indicator, and the runout of the large end face is less than 0.02mm. Machining is performed using a YG8 carbide cutting tool 7. During machining, high-grade water-soluble cutting fluid Sakura Kaken S-12 is used to reduce the cutting temperature. The cutting speed is 45m / min, the feed rate is 0.1mm / r, and the depth of cut is 0.05mm.

[0090] In this invention, the first clamp 4 has a circular plate-like structure. One end of the first clamp 4 is provided with a circular boss end face that is adapted to the inner cavity of the polygonal thin-walled workpiece 3 to be processed, and the other end is provided with a connecting step surface that is connected to the four-jaw chuck 5. The first clamp 4 is provided with a first clamp connecting hole in a ring around its periphery. The boss end face of the first clamp 4 is flat against the inner cavity of the polygonal thin-walled workpiece 3 to be processed and is fixed by fastening screws 6. This can effectively reduce the runout of the workpiece along the spindle direction of the machine tool when cutting the large end face, thereby improving the flatness of the large end face and effectively controlling the deformation of the polygonal thin-walled workpiece 3 during processing.

[0091] Furthermore, during the machining process in step 12, the second fixture 8 is first tightly connected to the connecting column 2 through its inner hole. At the same time, the thin-walled surface of the large end of the polygonal thin-walled workpiece 3 is flat against the end face of the second fixture 8. Then, four sets of fastening screws 6 are passed through the fastening holes on the polygonal thin-walled workpiece 3 to fix the polygonal thin-walled workpiece 3 to the second fixture 8, ensuring a coaxiality of Φ0.05mm. Next, the other end of the step surface of the second fixture 8 is clamped by a four-jaw chuck 5 connected to the CNC lathe for precision turning. During machining, the outer circle is aligned using a lever dial indicator to ensure that the runout of the end face is less than 0.02mm. Machining is performed using a YG8 carbide cutting tool 7. During machining, high-grade water-soluble cutting fluid Sakura Kaken S-12 is used to reduce the cutting temperature. The cutting speed is 45m / min, the feed rate is 0.1mm / r, and the depth of cut is 0.05mm.

[0092] In this invention, the second clamp 8 is a circular plate structure with an inner hole through the middle and a second clamp connecting hole around its periphery. The second clamp 8 is tightly connected to the connecting post 2 through the inner hole. At the same time, the thin wall surface of the large end of the polygonal thin-walled workpiece 3 is flat against the end face of the second clamp 8. The polygonal thin-walled workpiece 3 is fixed to the second clamp 8 by four sets of fastening screws 6 passing through the fastening holes on the polygonal thin-walled workpiece 3. This can avoid tool deflection when machining the outer steps, inner grooves and inner cavity thin walls, effectively control the flatness of the thin wall surface, and effectively control the deformation of the polygonal thin-walled workpiece 3 during machining.

[0093] In this invention, the inner hole of the second clamp 8 and the outer diameter of the connecting column 2 are matched and connected with each other as a precision reference, thereby effectively ensuring the coaxiality accuracy requirement of Φ0.05mm for the polygonal thin-walled workpiece 3. The clamping method combining the second clamp 8 and the four-jaw chuck 5 effectively improves the clamping accuracy and reduces the production cost.

[0094] Furthermore, in step 2, eliminating the residual internal stress of the blank in step 1 is achieved by placing the blank at room temperature into an artificial aging furnace, heating it to 185 to 195 degrees Celsius, maintaining it for 6 to 8 hours, and then cooling it to room temperature with the furnace after the heat treatment is completed.

[0095] In step 5, the residual internal stress of the polygonal thin-walled workpiece 3 in step 4 is eliminated by placing the aluminum alloy polygonal thin-walled workpiece 3 at room temperature into an artificial aging furnace, heating it to 220 degrees Celsius, holding it for 6 hours, and then cooling it to room temperature with the furnace after the holding period.

[0096] In step 7, the residual internal stress on the rough-machined polygonal thin-walled workpiece 3 in step 6 is eliminated by placing the rough-machined polygonal thin-walled workpiece 3 at room temperature into an artificial aging furnace, heating it to 220 degrees Celsius, maintaining it for 6 hours, and then cooling it to room temperature with the furnace after the heat treatment is completed.

[0097] In step 9, the residual internal stress on the semi-finished polygonal thin-walled workpiece 3 in step 8 is eliminated by placing the semi-finished polygonal thin-walled workpiece 3 at room temperature into an artificial aging furnace, heating it to 220 degrees Celsius, maintaining it for 6 hours, and then cooling it to room temperature with the furnace after the heat treatment is completed.

[0098] In this invention, eliminating residual internal stress can effectively reduce processing deformation.

[0099] In summary, a more specific embodiment of the present invention is as follows:

[0100] Before using the above-mentioned aluminum alloy polygonal thin-walled part machining process, it is necessary to manufacture and install it as a backup.

[0101] Example

[0102] The following explanation uses a polygonal thin-walled workpiece 3, which is applied to a functional component at a certain vibration frequency, as an example:

[0103] Step 1: Aluminum alloy blank bar stock, thin-walled part 1 Φ325mm×30mm; connecting column 2 Φ35mm×60mm;

[0104] Step 2: Eliminate the residual internal stress of the aluminum alloy blanks for thin-walled parts 1 and connecting column 2. Place the blanks at room temperature into an artificial aging furnace, heat them to 185 to 195 degrees Celsius, and maintain the temperature for 6 to 8 hours. After the holding period, cool them to room temperature with the furnace.

[0105] Step 3: The CNC lathe clamps the outer surfaces of the thin-walled part 1 and the connecting column 2 using a three-jaw self-centering chuck, and aligns the outer circles using a lever dial indicator to ensure runout is less than 0.3mm. Using a CNC program, a YG8 carbide cutting tool 7 is selected to machine the threaded hole of the thin-walled part and the external thread section of the connecting column. The cutting speed is 25m / min, the feed rate is 1.2mm / r, and the depth of cut is 1mm. Specifically, the thin-walled part 1 has an outer contour dimension of Φ325mm to Φ320mm, a step to Φ30mm, and an internal thread of M10mm with a depth of 10mm, and an internal chamfer of C10mm. The connecting column 2 has an outer contour dimension of Φ35mm to Φ30mm, an external thread of M10mm with a thread length of 10mm, and a chamfer of C10mm at the thread root.

[0106] Step 4: Screw the threaded end of the connecting post 2 into the threaded hole of the thin-walled part, and weld the connecting end of the connecting post 2 and the thin-walled part 1 to form the shape structure of the polygonal thin-walled workpiece 3.

[0107] Step 5: Place the aluminum alloy polygonal thin-walled workpiece 3, which is at room temperature, into an artificial aging furnace, heat it to 220 degrees Celsius, keep it at that temperature for 6 hours, and then cool it to room temperature with the furnace after the heat treatment is completed.

[0108] Step 6: The CNC lathe clamps the outer cylindrical surface of the thin-walled part 1 of the polygonal thin-walled workpiece 3 using a three-jaw self-centering chuck. The outer diameter is aligned using a lever dial indicator to ensure runout is less than 0.5mm. A YG8 carbide cutting tool 7 is used for machining at a cutting speed of 25m / min, a feed rate of 1.2mm / r, and a depth of cut of 1mm. Rough turning is performed on one side of the large end face of the thin-walled part 1 until it is smooth. The inner cavity is then bored. To a size of Φ230mm, depth of 12mm, boring inner groove To a dimension of Φ243mm, inner groove Φ250mm±0.05mm to a dimension of Φ249mm, depth 7mm; turn around, use a three-jaw self-centering chuck to support the inner cavity surface Φ230mm of the polygonal thin-walled workpiece 3, align the outer circle using a lever dial indicator to ensure runout is less than 0.5mm, rough turn one side of the thin-walled part 1 outer contour to Φ318mm, rough turn the stepped surface. To a dimension of Φ281.5mm, and rough-machine the outer contour on one side of the connecting cylinder. Up to dimension Φ26.5mm;

[0109] Step 7: Place the rough-machined polygonal thin-walled workpiece 3 at room temperature into an artificial aging furnace, heat it to 220 degrees Celsius, maintain it for 6 hours, and after the heat treatment is completed, cool it to room temperature with the furnace.

[0110] Step 8: Using a CNC lathe, the outer cylindrical surface of the thin-walled part 1 of the polygonal thin-walled workpiece 3 is clamped by a three-jaw self-centering chuck. The outer diameter is aligned using a lever dial indicator to ensure runout is less than 0.1mm. A YG8 carbide cutting tool 7 is selected for machining at a cutting speed of 40m / min, a feed rate of 0.7mm / r, and a depth of cut of 0.9mm. The large end face of one side of the thin-walled part 1 is semi-finished until it is smooth. The inner cavity is then bored. To a dimension of Φ230.5mm and a depth of 12.8mm, bore the inner groove. To a dimension of Φ242.5mm, the inner groove Φ250mm±0.05mm to a dimension of Φ249.5mm, with a depth of 7.5mm; turn around, and use a three-jaw self-centering chuck to support the inner cavity surface Φ231.5mm of the polygonal thin-walled workpiece 3. Align the outer circle using a lever dial indicator to ensure runout is less than 0.5mm. Semi-finish turn one side of the outer contour of the thin-walled part 1 to Φ316mm, and semi-finish turn the stepped surface. To a dimension of Φ280.5mm, and semi-finish machine the outer contour of the connecting cylindrical surface on one side. Up to dimension Φ25.5mm;

[0111] Step 9: Place the rough-machined polygonal thin-walled workpiece 3 at room temperature into an artificial aging furnace, heat it to 220 degrees Celsius, maintain it for 6 hours, and after the heat treatment is completed, cool it to room temperature with the furnace.

[0112] Step 10: Using a CNC milling machine and its paired three-jaw self-centering chuck, the inner cavity of the polygonal thin-walled workpiece 3 (Φ230.5mm) is supported. The outer circle is aligned using a lever dial indicator, with runout less than 0.02mm. A carbide end mill is used for machining, milling the 10-sided contour in the top view, ensuring a dimension of 300mm. In the same coordinate system, four Φ6.5mm holes and a flat-bottomed hole of Φ12mm on the Φ264mm pitch circle are machined to a depth of 9mm. Small square steps of 15mm and Φ10mm are milled, controlling the dimension to 15mm. During machining, high-grade water-soluble cutting fluid Sakura Kaken S-12 is used to reduce the cutting temperature. The spindle speed is 8500r / min, the cutting depth is 1mm, and the cutting parameters are 0.05mm.

[0113] Step 11: First, the boss of the first fixture 4 is tightly fitted to the inner cavity Φ230.5mm of the polygonal thin-walled workpiece 3. Then, four sets of fastening screws 6 are passed through the fastening holes 4×Φ6.5mm on the polygonal thin-walled workpiece 3 to fix the workpiece 3 to the first fixture 4, ensuring a coaxiality of Φ0.05mm. Next, the other end of the first fixture 4 is securely connected by a four-jaw chuck 5 connected to the CNC lathe for precision turning. The outer circle is aligned using a lever dial indicator, with the large end face runout less than 0.02mm. The workpiece is then machined using a YG8 carbide cutting tool 7, finishing the small end face on one side of the connecting column and the outer contour on the connecting column side. Car steps During machining, use high-grade water-soluble cutting fluid Sakura Kaken S-12 to reduce cutting temperature, with a cutting speed of 45m / min, a feed rate of 0.1mm / r, and a depth of cut of 0.05mm.

[0114] Step 12: First, the inner hole of the second fixture 8 is tightly connected to the connecting column 2. Simultaneously, the thin-walled surface of the large end of the polygonal thin-walled workpiece 3 is flush with the end face of the second fixture 8. Then, four sets of fastening screws 6 are passed through the fastening holes on the polygonal thin-walled workpiece 3 to fix it to the second fixture 8, ensuring a coaxiality of Φ0.05mm. Next, the stepped surface of the other end of the second fixture 8 is clamped by a four-jaw chuck 5 connected to the CNC lathe for precision turning. During machining, a dial indicator is used to align the outer circle, ensuring the runout of the end face is less than 0.02mm. Machining is then performed using a YG8 carbide cutting tool 7, with an offset length of 15mm, boring the inner cavity. Control the wall thickness to 1.6mm ± 0.05mm, and bore the inner groove. From Φ250mm±0.05mm to size Φ249mm, depth 8mm, use high-grade water-soluble cutting fluid Sakura Kaken S-12 to reduce cutting temperature during machining, cutting speed 45m / min, feed rate 0.1mm / r, depth of cut 0.05mm.

[0115] In step 12 above, to effectively control the deformation of the polygonal thin-walled workpiece 3 during machining, the inner hole of the second fixture 8 is tightly fitted with the step ΦⅢ of the polygonal thin-walled workpiece 3. At the same time, the thin-walled surface of the large end of the polygonal thin-walled workpiece 3 is flat against the end face of the second fixture 8. Four sets of fastening screws 6 are used to fix the polygonal thin-walled workpiece 3 to the second fixture 8, avoiding tool deflection when machining the outer step, inner groove, and inner cavity thin-walled surface, effectively controlling the flatness of the thin-walled surface, and ensuring coaxiality Φ0.05mm. A universal four-jaw chuck 5 is used to clamp the other end of the step surface of the second fixture 8. A lever dial indicator is used to calibrate the outer circle and end face runout to within 0.02mm. A cemented carbide YG8 turning tool 7 is selected for machining. During machining, high-grade water-soluble cutting fluid Sakura Kaken S-12 is used to reduce the cutting temperature. The cutting speed is 45m / min, the feed rate is 0.1mm / r, and the depth of cut is 0.05mm. This step is to machine the outer steps, inner cavities, and inner grooves of the polygonal thin-walled workpiece 3 in the precision turning process, so that the dimensions of the machined part meet the technical requirements of the drawing, while the form and position tolerance and coaxiality are Φ0.05mm.

[0116] The polygonal thin-walled finished part 9, which is processed as described above, is applied to a certain vibration frequency functional component. The requirements for its wall thickness dimensional accuracy, parallelism, and coaxiality will affect the function of the component. Through theoretical calculation and experimental analysis, the dimensional accuracy of the wall thickness will directly affect the vibration frequency, amplitude, period, and other parameter values ​​of the component. Therefore, the control of the process method is the key to whether the polygonal thin-walled part 3 to be processed can meet the function of the component.

[0117] Finally, it should be noted that the above description is merely a preferred embodiment of the present invention and is not intended to limit the present invention in any other way. Any person skilled in the art may make changes or modifications to the above-disclosed technical content to create equivalent embodiments. However, any simple modifications, equivalent changes, and modifications made to the above embodiments based on the technical essence of the present invention without departing from the scope of the present invention shall still fall within the protection scope of the present invention.

Claims

1. A machining process for thin-walled polygonal aluminum alloy parts, characterized in that, Includes the following steps: Step 1: Blank aluminum alloy plates are cut using a horizontal band saw. Step 2: Eliminate the residual internal stress in the blank plate from Step 1; Step 3: The blank in Step 2 is processed by a CNC lathe to obtain a thin-walled part (1) and a connecting column (2), with an overall allowance of 2mm to 2.5mm. The thin-walled part screw hole is machined in the middle of the thin-walled part (1) and the external thread section of the connecting column (2) is machined at one end. Step 4: Screw the threaded end of the connecting post (2) into the threaded hole of the thin-walled part, and weld the connecting end of the connecting post (2) and the thin-walled part (1) to form the shape structure of the polygonal thin-walled workpiece (3); Step 5: Eliminate the residual internal stress in the shape structure of the polygonal thin-walled workpiece (3) from Step 4; Step 6: Roughly machine the outer contour and inner cavity of the polygonal thin-walled workpiece (3) using a CNC lathe, leaving an overall allowance of 0.8mm to 1.2mm; Step 7: Eliminate the residual internal stress on the polygonal thin-walled workpiece (3) that was rough-machined in Step 6; Step 8: The outer contour and inner cavity of the polygonal thin-walled workpiece (3) are machined by semi-finish turning on a CNC lathe, with an overall allowance of 0.3mm to 0.5mm. Step 9: Eliminate the residual internal stress on the semi-finished polygonal thin-walled workpiece (3) from Step 8; Step 10: Mill the target structure of the polygonal thin-walled workpiece (3) using a CNC milling machine according to the dimensions of the target structure; Step 11: The target structure is precision machined using a CNC lathe to a depth of 0.1 mm. Step 12: Control the CNC lathe tool (7) to turn around and perform machining, while ensuring that all dimensional tolerances and geometric tolerances meet the dimensions of the target structural drawing. After machining, an aluminum alloy polygonal thin-walled finished part (9) is obtained.

2. The machining process for thin-walled polygonal aluminum alloy parts according to claim 1, characterized in that, In step 3, the CNC lathe clamps the outer surfaces of the thin-walled part (1) and the connecting column (2) using a three-jaw self-centering chuck, and uses a lever dial indicator to align the outer circles to ensure that the runout is less than 0.3 mm. The CNC lathe uses a YG8 carbide cutting tool (7) to machine the threaded holes of the thin-walled part and the external threaded section of the connecting column. The cutting speed is 25 m / min, the feed rate is 1.2 mm / r, and the depth of cut is 1 mm. The overall allowance for the outer contour dimensions of the thin-walled part (1) and the connecting column (2) is 2 mm to 2.5 mm to eliminate the influence of the deformation generated during the welding process in the next step on the semi-finishing and finishing processes.

3. The machining process for thin-walled polygonal aluminum alloy parts according to claim 1, characterized in that, The polygonal thin-walled workpiece (3) to be processed in step 4 includes: A thin-walled part (1) is fixedly connected to the middle of the thin-walled part (1), and a screw hole for the thin-walled part is opened in the middle of the non-fixed end of the fixing part (11). The connecting column (2) has an external thread section (21) at one end of its body that is compatible with the internal thread of the thin-walled part, and a square column (22) is connected to the other end of its body. The square column (22) also has a through hole. Among them, the non-fixed end of the fastener (11) is provided with a fastener circumferential welding part that is easy to weld, and the connection end of the connecting column body and the connecting column external thread section (21) is provided with a connecting column body circumferential welding part that is easy to weld with the fastener circumferential welding part.

4. The machining process for thin-walled polygonal aluminum alloy parts according to claim 1, characterized in that, In the welding process of step 4, argon arc welding is used for welding, and the weld seam is a V-type welding method. The circumferential welding part of the fastener and the circumferential welding part of the connecting column body are welded and fixed together, thereby welding the thin-walled part (1) and the connecting column (2) into the shape structure of the polygonal thin-walled workpiece (3).

5. The machining process for thin-walled polygonal aluminum alloy parts according to claim 1, characterized in that, In step 6, the CNC lathe clamps the outer surface of the thin-walled part (1) of the polygonal thin-walled workpiece (3) with a three-jaw self-centering chuck. The outer circle is aligned with a lever dial indicator to ensure that the runout is less than 0.5 mm. A YG8 carbide cutting tool (7) is used for machining. The cutting speed is 25 m / min, the feed rate is 1.2 mm / r, and the depth of cut is 1 mm. The large end face of one side of the thin-walled part (1) is rough-turned until it is smooth, and the inner cavity surface and inner groove are bored. The lathe is turned around, and the inner cavity surface of the polygonal thin-walled workpiece (3) is supported by the three-jaw self-centering chuck. The outer circle is aligned with a lever dial indicator to ensure that the runout is less than 0.5 mm. The outer contour and step surface of one side of the thin-walled part (1) are rough-turned, and the outer contour of the connecting cylindrical side is also rough-turned.

6. The machining process for a thin-walled polygonal aluminum alloy part according to claim 1, characterized in that, In step 8, a CNC lathe is used to clamp the outer surface of the thin-walled part (1) of the polygonal thin-walled workpiece (3) with a three-jaw self-centering chuck. The outer circle is aligned with a lever dial indicator to ensure that the runout is less than 0.1 mm. A carbide YG8 cutting tool (7) is used for machining. The cutting speed is 40 m / min, the feed rate is 0.7 mm / r, and the depth of cut is 0.9 mm. The large end face of one side of the thin-walled part (1) is semi-finished until it is smooth, and the inner cavity surface and inner groove are bored. The lathe is turned around, and the inner cavity surface of the polygonal thin-walled workpiece (3) is supported by the three-jaw self-centering chuck. The outer circle is aligned with a lever dial indicator to ensure that the runout is less than 0.1 mm. The outer contour and step surface of one side of the thin-walled part (1) are rough-machined, and the outer contour of the connecting cylindrical side is also rough-machined.

7. The machining process for thin-walled polygonal aluminum alloy parts according to claim 1, characterized in that, In the processing of step 10, according to the size of the target structure, a CNC milling machine is used to clamp the inner cavity structure of the polygonal thin-walled workpiece (3) with a three-jaw self-centering chuck that is matched with it. The outer circle is aligned by lever dial indicator, and the runout is less than 0.02mm. The target structure is then machined by carbide milling cutter. During the machining, high-grade water-soluble cutting fluid (Sakura Kaken S-12) is used to reduce the cutting temperature. The spindle speed is 8500r / min, the cutting depth is 1mm, and the cutting amount is 0.05mm. The target structure is to mill a 10-sided profile, a flat-bottomed hole, and several fastening holes on the non-connecting column end of the thin-walled part (1), wherein the fastening holes penetrate the front and back of the thin-walled part (1); and to mill a square small step structure and an inner hole on the connecting column end of the thin-walled part (1).

8. The machining process for thin-walled polygonal aluminum alloy parts according to claim 1, characterized in that, In step 11, the first fixture (4) is tightly fitted with the inner cavity of the polygonal thin-walled workpiece (3) by the boss of the first fixture (4). Then, four sets of fastening screws (6) are passed through the fastening holes on the polygonal thin-walled workpiece (3) to fix the polygonal thin-walled workpiece (3) to the first fixture (4) together, while ensuring coaxiality Φ0.05mm. Then, the other end of the first fixture (4) is firmly connected by a four-jaw chuck (5) connected to the CNC lathe for precision turning. During the precision machining, the outer circle is aligned by a lever dial indicator, and the runout of the large end face is less than 0.02mm. The machining is carried out by a turning tool (7) made of cemented carbide YG8 material. During the machining, a high-grade water-soluble cutting fluid (Sakura Kaken S-12) is used to reduce the cutting temperature. The cutting speed is 45m / min, the feed rate is 0.1mm / r, and the depth of cut is 0.05mm.

9. The machining process for a thin-walled polygonal aluminum alloy part according to claim 1, characterized in that, In step 12, the inner hole of the second fixture (8) is first tightly connected to the connecting column (2), and the thin wall surface of the large end of the polygonal thin-walled workpiece (3) is flat against the end face of the second fixture (8). Then, four sets of fastening screws (6) are passed through the fastening holes on the polygonal thin-walled workpiece (3) to fix the polygonal thin-walled workpiece (3) to the second fixture (8) together, while ensuring coaxiality Φ0.05mm. Then, the step surface of the other end of the second fixture (8) is clamped by the four-jaw chuck (5) connected to the CNC lathe for precision turning. During machining, the outer circle is aligned by lever dial indicator to ensure that the runout of the end face is less than 0.02mm. Machining is performed by a turning tool (7) made of cemented carbide YG8 material. During machining, high-grade water-soluble cutting fluid (Sakura Kaken S-12) is used to reduce the cutting temperature. The cutting speed is 45m / min, the feed rate is 0.1mm / r, and the depth of cut is 0.05mm.

10. The machining process for a thin-walled polygonal aluminum alloy part according to claim 1, characterized in that, In step 2, the residual internal stress of the blank in step 1 is eliminated by placing the blank at room temperature into an artificial aging furnace, heating it to 185 to 195 degrees Celsius, maintaining it for 6 to 8 hours, and then cooling it to room temperature with the furnace after the holding period. In step 5, the residual internal stress of the polygonal thin-walled workpiece (3) in step 4 is eliminated by placing the aluminum alloy polygonal thin-walled workpiece (3) at room temperature into an artificial aging furnace, heating it to 220 degrees Celsius, holding it for 6 hours, and then cooling it to room temperature with the furnace after the heat treatment is completed. In step 7, the residual internal stress on the rough-machined polygonal thin-walled workpiece (3) in step 6 is eliminated by placing the rough-machined polygonal thin-walled workpiece (3) at room temperature into an artificial aging furnace, heating it to 220 degrees Celsius, maintaining it for 6 hours, and then cooling it to room temperature with the furnace after the heat preservation is completed. In step 9, the residual internal stress on the semi-finished polygonal thin-walled workpiece (3) in step 8 is eliminated by placing the semi-finished polygonal thin-walled workpiece (3) at room temperature into an artificial aging furnace, heating it to 220 degrees Celsius, maintaining it for 6 hours, and then cooling it to room temperature with the furnace after the heat preservation is completed.

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