An integrated processing method for thin-walled metal parts

Abstract

The present invention relates to the field of metal sheet processing, and specifically relates to an integrated processing method for metal thin-walled parts. The processing of aluminum alloy thin-walled parts is difficult due to repeated positioning in multiple processes and the need for customized tooling, resulting in a long production cycle, high cost, and serious waste of resources for the parts. Based on a dual-robot structure, the present invention uses double-sided incremental forming, rolling surface treatment, and mirror milling process to complete the forming, surface treatment, and machining of the parts in one clamping at the same station without using a mold, reducing the processing procedures of the parts, avoiding customized molds and tooling processing, thereby reducing the manufacturing cost and cycle of metal thin-walled parts.

Description

Technical Field

[0001] The present invention relates to the field of metal sheet processing, and specifically relates to an integrated processing method for metal thin-walled parts. Background Art

[0002] Aluminum alloy thin-walled parts are usually used as the outer skin parts of products and are widely used in aviation, aerospace, automobiles, ships, etc. Aluminum alloy thin-walled parts usually use die forming methods such as stamping to form the shape of the parts; then, surface treatment processes such as shot peening are used to improve the fatigue, corrosion resistance and wear resistance of the materials; finally, processes such as chemical milling and machining are used to achieve local thinning, milling holes, trimming edges, etc. of the parts. Due to the difficulty of repeated positioning in multiple processes and the need for customized die tooling, the production cycle of the parts is long, the cost is high, and the resource waste is serious. Summary of the Invention

[0003] Based on the existing problems, the purpose of the present invention is to propose an integrated processing method for metal thin-walled parts to solve the problems of long production cycle and high cost of complex-shaped thin-walled parts.

[0004] Based on a dual-robot structure, the present invention uses double-sided incremental forming, rolling surface treatment and mirror milling processes. Without using a die, the forming, surface treatment and machining of the part can be completed in one clamping at the same station, reducing the part processing procedures, avoiding customized die and tooling processing, and thus reducing the manufacturing cost and cycle of metal thin-walled parts.

[0005] The present invention proposes an integrated processing method for metal thin-walled parts, and the forming, surface treatment and machining of the part can be completed in one clamping at the same station. The method includes the following steps:

[0006] S100 Fix the metal sheet to the frame fixture, and the frame fixture vacates the processing area of the metal sheet.

[0007] S200 Double-sided incremental forming of thin-walled parts

[0008] Install incremental forming tools on the robots on both sides of the metal sheet. According to the thickness and strength of the metal sheet, set the step depth, forming tool and forming trajectory of double-sided incremental forming. Through the robot, control the incremental forming tool to perform double-sided extrusion forming on the metal sheet under the predetermined temperature condition according to the forming trajectory and forming process parameters, so that the shape of the thin-walled part meets the predetermined requirements.

[0009] S300 Rolling surface treatment of thin-walled parts

[0010] Install a rolling tool on the robots on both sides, set the row spacing, rolling pressure and rolling trajectory for the rolling process, control the rolling tool through the robots, and perform rolling on both sides of the thin-walled part a set number of times according to the rolling trajectory (10) and rolling process parameters under the predetermined temperature condition, so as to improve the surface performance of the thin-walled part to meet the predetermined requirements;

[0011] S400 Mirror Milling of Thin-Walled Parts

[0012] Install a mirror milling combination tool on the robot, set the row spacing, feed rate and machining trajectory for mirror milling, and control the mirror milling tool through the robot to machine the thin-walled part, so that the thickness and dimensions of the part meet the predetermined requirements.

[0013] Advantageously, the frame fixture includes a front frame and a back frame, and clamps the metal sheet on both sides.

[0014] Advantageously, the incremental forming tool includes a fixed ball head forming tool, a rolling ball head forming tool and a disc forming tool, and the material of the incremental forming tool is cemented carbide, steel or ceramic.

[0015] Advantageously, the forming trajectory is a single-pass forming trajectory or a multi-pass forming trajectory.

[0016] Advantageously, the predetermined temperature condition during the incremental forming process includes: room temperature environment or a high temperature environment created by self-resistance heating of the incremental forming tool by a DC power supply.

[0017] Advantageously, the rolling tool includes a fixed ball head rolling tool and a rolling ball head rolling tool.

[0018] Advantageously, the rolling tool realizes the set output rolling pressure through a pneumatic system, a hydraulic system or an electric system.

[0019] Advantageously, the predetermined temperature condition during the rolling process includes: room temperature environment or a low temperature environment created by spraying liquid nitrogen from a liquid nitrogen nozzle.

[0020] Advantageously, the mirror milling combination tool includes an electric spindle installed on one side robot and a support disk installed on the other side robot. A milling cutter is installed on the electric spindle for machining from one side, and a support disk is installed on the other side robot for support.

[0021] Advantageously, mirror milling includes machining of metal thin-walled parts, including: local thinning, trimming or hole making.

[0022] The beneficial effects of the present invention compared with the prior art are:

[0023] 1. In a single set of equipment, through one-time material clamping, the present invention can achieve all process operations such as the forming, surface treatment, and machining of metal thin-walled parts. Compared with the traditional multi-process, due to the transfer of parts between different equipment in the traditional multi-process, the development of customized fixtures and part positioning are effectively reduced, and the development cycle of parts is effectively shortened.

[0024] 2. Through flexible manufacturing processes such as double-sided incremental forming, rolling surface treatment, and mirror milling, the present invention effectively reduces the development cycle and cost of parts compared with the need to process customized molds in the manufacturing process of traditional thin-walled parts.

[0025] 3. The present invention uses a robot as the manufacturing equipment for thin-walled parts, effectively reducing the cost and cycle of the research and development of special equipment compared with the special equipment used in traditional manufacturing. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] In order to more clearly illustrate the technical solutions in the present invention, the following will briefly introduce the drawings required for use in the description of the embodiments or the prior art. Obviously, the following drawings are only some embodiments of the present invention. For those of ordinary skill in the art, without creative efforts, other drawings can be obtained based on these drawings.

[0027] Figure 1 It is a process flow chart of an integrated processing method taking an aluminum alloy plate as an example;

[0028] Figure 2 It is a schematic diagram of the clamping and processing of the sheet material in Example 1;

[0029] Figure 3 It is a schematic diagram of the clamping of the sheet material in Example 1;

[0030] Figure 4 It is a schematic diagram of incremental forming in Example 1;

[0031] Figure 5 It is a schematic diagram of incremental forming in Example 2;

[0032] Figure 6 It is a schematic diagram of incremental forming in Example 3;

[0033] Figure 7 It is a schematic diagram of incremental forming in Example 4;

[0034] Figure 8 It is a schematic diagram of rolling in Example 1;

[0035] Figure 9 It is a schematic diagram of rolling in Example 3;

[0036] Figure 10 It is a schematic diagram of mirror milling in Example 1;

[0037] Figure 11 It is a schematic diagram of mirror milling holes;

[0038] Figure 12 It is a schematic diagram of mirror milling cut edges.

[0039] Among them, 1. Frame fixture; 2. Fixed ball head forming tool; 3. Aluminum alloy sheet; 4. Forming trajectory; 5. Rolling ball head forming tool; 6. Disk forming tool; 7. DC power supply; 8. Fixed ball head rolling tool; 9. Rolling trajectory; 10. Rolling pressure; 11. Rolling ball head rolling tool; 12. Liquid nitrogen nozzle; 13. Electric spindle; 14. Support disk Specific implementation manners

[0040] In the following description, for the purpose of illustration rather than limitation, specific details such as specific system structures and technologies are put forward in order to thoroughly understand the embodiments of the present invention. However, those skilled in the art should clearly understand that the present invention can also be implemented in other embodiments without these specific details. In other cases, detailed descriptions of well-known systems, devices, circuits and methods are omitted so as not to impede the description of the present invention with unnecessary details.

[0041] The following will specifically describe the one-piece processing method of aluminum alloy thin-walled parts according to the present invention with reference to the accompanying drawings.

[0042] Figure 1 It is a process flow chart of the one-piece processing method taking an aluminum alloy sheet as an example according to the present invention. As Figure 1 shown, the method includes:

[0043] S100 Fix the aluminum alloy sheet to the frame fixture.

[0044] S200 Double-sided incremental forming process of the thin-walled part: Install incremental forming tools on the robots on both sides. According to the thickness and strength of the material, set the step depth, forming tools and forming trajectories of the double-sided incremental forming. Control the forming tools through the robots, and form the aluminum alloy sheet according to the forming trajectories and forming process parameters under the predetermined temperature conditions, so that the shape of the thin-walled part meets the predetermined requirements.

[0045] In step S200, the incremental forming tools can be fixed ball head forming tools, rolling ball head forming tools and disk forming tools, and the tool materials are cemented carbide, steel or ceramic.

[0046] In step S200, the robots on both sides achieve the linkage of the robotic arms through parallel connection at the underlying operating system level, ensuring that the robots can reach the specified positions simultaneously under the set trajectory. During the forming process, a forming trajectory is generated by trajectory software based on the contour of the part. Among them, by setting the relative distance between the two incremental forming tools, the set relative positions of the forming tools on both sides are maintained during the forming process.

[0047] In step S200, the forming trajectory can be a single-pass forming trajectory or a multi-pass forming trajectory.

[0048] In step S200, the predetermined temperature conditions include: room temperature environment, high-temperature environment created by self-resistance heating when powered on.

[0049] S300 Process of rolling surface treatment for thin-walled parts: Install rolling tools on the robots on both sides, set the row spacing, rolling pressure, and rolling direction of the rolling treatment, and control the rolling tools through the robots to perform a set number of rolls on the thin-walled parts according to the rolling trajectory and rolling process parameters under the predetermined temperature conditions, so as to improve the surface performance of the thin-walled parts to meet the predetermined requirements.

[0050] In step S300, the rolling tool is a fixed ball-head rolling tool or a rolling ball-head rolling tool.

[0051] In step S300, the rolling tool realizes the set output rolling pressure through a pneumatic system, a hydraulic system, or an electric system.

[0052] In step S300, the robots on both sides need to reach the specified positions simultaneously. During the surface treatment process, a forming trajectory is generated by trajectory software based on the contour of the part. At any trajectory position, the centerlines of the two rolling tools are in the normal direction of the part surface.

[0053] In step S300, the predetermined temperature conditions include: room temperature environment, low-temperature environment created by liquid nitrogen.

[0054] In step S300, during the process of performing a set number of rolls on the thin-walled parts, the rolling tools are processed by using the same trajectory process parameters or different adjusted trajectory process parameters.

[0055] S400 Process of mirror milling for thin-walled parts: Install a mirror milling combination tool on the robot, set the row spacing, feed rate, and machining trajectory of the mirror milling, and control the mirror milling tool through the robot to perform machining on the thin-walled parts so that the thickness and dimensions of the parts meet the predetermined requirements.

[0056] In step S400, the mirror milling combination tool is an electric spindle and a support disk. The electric spindle is installed on the robot on the machining side, and the material is locally machined by the milling cutter on the electric spindle; the support disk is installed on the robot on the support side and contacts the material during the machining process to offset the cutting force and ensure that the material does not deform during the cutting process.

[0057] In step S400, the machining of the thin-walled part includes: local thinning, trimming, and hole making.

[0058] Through the above methods of double-sided incremental forming, rolling surface treatment, and mirror milling of the metal sheet, the part shape is formed, the material properties of the part are improved, and the material thickness distribution is controlled to meet the predetermined requirements.

[0059] The following further describes the integrated machining method of the aluminum alloy thin-walled part of the present invention in conjunction with embodiments.

[0060] Embodiment 1

[0061] Figures 2 - 4 、 Figure 8 and Figure 10 are machining embodiments of the aluminum alloy thin-walled part. It is planned to use a 2.0 mm 2024-O aluminum alloy sheet as the material to illustrate the specific implementation steps of the present invention:

[0062] Step 1: Fix the aluminum alloy sheet 3 in the frame fixture 1, and two 500 kg industrial robots are located on both sides of the sheet.

[0063] Step 2: Install a fixed ball head forming tool 2 with a radius of 15 mm at the end of the industrial robots on both sides. The material of the fixed ball head forming tool 2 is cemented carbide, and the material grade is YG15. The relative distance between the two fixed ball head forming tools 2 is set to 26 mm to ensure that the outer tool supports the inner tool. At room temperature, a forming trajectory 4 with a step depth of 0.5 mm and a single pass is used to form the part, and the part is formed by the double-sided incremental forming method;

[0064] Step 3: Replace the tool at the end of the industrial robot with a fixed ball head rolling tool 8 with a radius of 3 mm. The material of this tool is cemented carbide, and the material grade is YG15. Apply a rolling pressure of 300 N with a pneumatic system, the row spacing of the rolling trajectory 9 is 0.05 mm, and the material surface is treated by the rolling surface treatment method 10 times;

[0065] Step 4: Replace the tool at the end of the industrial robot with a mirror milling combination tool. Install a ball mill with an R5 on the electric spindle 13. The support disk 14 has a diameter of 80 mm and is made of acetal. Machine the surface of the material with a line spacing of 0.1 mm, a feed rate of 0.05 mm, and a feed speed of 5000 mm / min. Machine the surface of the material by the mirror milling method and machine the material thickness to 1.2 mm.

[0066] The results show that the material strength is increased from the initial 74 MPa of the sheet to 350 MPa, an increase of 373%. The thickness deviation of the part is 0.05 mm, and the machining time of the part is 3 hours. The part shape forming and part forming can be quickly realized on a single set of equipment, and the material mechanical properties and thickness distribution of the part meet the design specifications.

[0067] Example 2

[0068] Figure 5 It is a progressive forming schematic diagram of Example 2 of the one-piece machining method of the metal thin-walled part of the present invention.

[0069] It is planned to use a 1.5-mm 7050-T6 aluminum alloy sheet as the material to illustrate the specific implementation steps of the present invention:

[0070] Step 1: Fix the aluminum alloy sheet 3 on the frame fixture 1. Two 1000-kg industrial robots are located on both sides of the aluminum alloy sheet 3.

[0071] Step 2: Install a rolling ball head forming tool 5 with a radius of 20 mm at the end of the industrial robot. The material of this tool is ceramic. At room temperature, set the relative distance between the rolling ball head forming tools on both sides to 27 mm. Adopt a forming trajectory 4 with a step depth of 1 mm and a single pass, and form the part by the double-sided progressive forming method;

[0072] Step 3: Replace the tool at the end of the industrial robot with a fixed ball head rolling tool 8 with a radius of 4 mm. The material of this tool is cemented carbide, and the material grade is YG15. Apply a rolling pressure of 500 N with a hydraulic system. The line spacing of the rolling trajectory 9 is 0.1 mm. Treat the surface of the material by the rolling surface treatment method, treat the surface 2 times, and treat the surface 3 times with the rolling process parameters of a rolling pressure of 800 N and a line spacing of 0.05 mm;

[0073] Step 4: Replace the tool at the end of the industrial robot with a mirror milling combination tool. Install a ball mill with an R10 on the electric spindle 13. The support disk 14 has a diameter of 100 mm and is made of acetal. Machine the surface of the material with a line spacing of 0.2 mm, a feed rate of 0.05 mm, and a feed speed of 5000 mm / min, and machine the material thickness to 1.0 mm by the mirror milling method.

[0074] The results show that the material strength is increased from 450 MPa of the initial sheet to 550 MPa, and the thickness deviation of the part is 0.08 mm. During the double-sided incremental forming process, using a ceramic rolling ball head forming tool to form the part surface can improve the surface quality of the material. The surface roughness of the material is 1.2 μm, which is better than 3.1 μm of the cemented carbide fixed ball head forming tool.

[0075] Example 3

[0076] It is planned to use a 2024-O aluminum alloy sheet 3 with a thickness of 2 mm as the material, combined with Figure 2 , Figure 3 , Figure 6 , Figure 8 , Figure 10 , Figure 11 and Figure 12 to illustrate the specific implementation steps of the present invention:

[0077] Step 1: Fix the aluminum alloy sheet 3 on the frame fixture 1, and two 1000 kg industrial robots are located on both sides of the aluminum alloy sheet 3.

[0078] Step 2: Install a rolling disc forming tool 6 with a radius of 10 mm at the end of the industrial robot. Its material is 45 steel. At room temperature, set the relative distance of the rolling disc forming tool 6 to 26 mm, adopt a step depth of 1 mm, a multi-pass forming trajectory 4, and the number of passes is five. Form the part by the double-sided incremental forming method;

[0079] Step 3: Replace the tool at the end of the industrial robot with a rolling ball head rolling tool 11 with a radius of 4 mm. Its material is cemented carbide, and the material grade is YG16. Apply a rolling pressure of 300 N with an electric system. The row spacing of the rolling trajectory 9 is 0.05 mm. Treat the material surface by the rolling surface treatment method, and treat the surface 10 times. At the same time of treatment, spray liquid nitrogen on the part surface through the liquid nitrogen nozzle 12 to keep the surface at a temperature of -200 K;

[0080] Step 4: Replace the tool at the end of the industrial robot with a mirror milling tool combination. Install a ball end mill with an R5 on the electric spindle 13. The diameter of the support disc 14 is 80 mm, and the material is acetal. Machine the material surface with a row spacing of 0.1 mm, a feed rate of 0.05 mm and a feed speed of 5000 mm / min by the mirror milling method, and machine the material thickness to 1.2 mm. Replace the flat end mill with a diameter of 8 mm, drill holes in the part at a feed speed of 500 mm / min, and trim the part at a feed speed of 300 mm / min.

[0081] The results show that the material strength is increased from 74 MPa of the initial sheet to 390 MPa, which significantly improves the material loudness compared with the rolling surface treatment at room temperature. This is because the low-temperature environment created by liquid nitrogen effectively inhibits recrystallization, resulting in smaller grain size and higher material strength under the same load conditions. By thinning, punching, and trimming the parts, the parts reach the final use state.

[0082] Example 4

[0083] Figure 7 It is a progressive forming schematic diagram of Example 4 of the integral processing method of the metal thin-walled parts of the present invention.

[0084] It is planned to use a 1.5-mm 7050-T6 aluminum alloy sheet 3 as the material, combined with Figure 2 , Figure 3 , Figure 7 , Figure 8 and Figure 10 to illustrate the specific implementation steps of the present invention:

[0085] Step 1: Fix the aluminum alloy sheet 3 on the frame fixture 1, and two 500-kg industrial robots are located on both sides of the sheet.

[0086] Step 2: Install a fixed ball head forming tool 2 with a radius of 15 mm at the end of the industrial robot. Its material is cemented carbide with the material grade YG15. The two fixed ball head forming tools 2 are respectively connected to the positive and negative poles of the DC power supply 7. Using a voltage of 36 V and a current of 115 A, the sheet is heated by the heat generated by its own resistance. The temperature at the position where the tool contacts the sheet reaches 250°C. Set the relative distance of the fixed ball head forming tool 2 to 27 mm, adopt a step depth of 1 mm, a single-pass forming trajectory, and form the part by the double-sided progressive forming method;

[0087] Step 3: Replace the tool at the end of the industrial robot with a fixed ball head rolling tool 8 with a radius of 4 mm. Its material is cemented carbide with the material grade YG15. At room temperature, apply a rolling pressure of 500 N with a hydraulic system. The row spacing of the rolling trajectory 9 is 0.1 mm. Treat the material surface by the rolling surface treatment method for 2 times, and treat the surface 3 times with the rolling process parameters of a rolling pressure of 800 N and a row spacing of 0.05 mm;

[0088] Step 4: Replace the tool at the end of the industrial robot with a mirror milling tool combination. Install a ball nose milling cutter with R10 on the electric spindle 13. The diameter of the support disk 14 is 100 mm, and its material is acetal. Adopt a row spacing of 0.2 mm, a feed rate of 0.05 mm, and a feed speed of 5000 mm / min. Machine the material surface by the mirror milling method and machine the material thickness to 1.0 mm.

[0089] The results show that the forming force can be significantly reduced by the double-sided incremental forming method with self-resistance heating, but the material strength of the part will be decreased. The material strength is increased from 450 MPa of the initial sheet to 500 MPa, which is less than that of the formed part at room temperature. This is because the heat generated by self-resistance heating will eliminate dislocations and cause recrystallization of the material, thus inhibiting the strain hardening effect of the material.

[0090] For the above-mentioned all optional technical solutions of the fixed ball head forming tool disc, any combination can be adopted to form the optional embodiments of the present application, which will not be elaborated one by one here.

[0091] It should be understood that the magnitudes of the sequence numbers of the steps in the above embodiments do not mean the order of execution. The order of execution of each process should be determined by its function and internal logic, and should not constitute any limitation to the implementation process of the embodiments of the present invention.

[0092] The above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit them; although the present invention has been described in detail with reference to the foregoing embodiments, those of ordinary skill in the art should understand that: they can still modify the technical solutions recorded in the foregoing embodiments, or perform equivalent replacements on some of the technical features; and these modifications or replacements do not make the essence of the corresponding technical solutions deviate from the spirit and scope of the technical solutions of the embodiments of the present invention, and should all be included in the protection scope of the present invention.

Claims

1. An integrated processing method for a thin-walled metal part, which can complete the forming, surface treatment and machining of the part through one clamping at the same station, is characterized in that, The method comprises the following steps: S100 Fix the metal sheet to the frame fixture (1), and the frame fixture (1) clears the processing area of the metal sheet; S200 Double-sided incremental forming of thin-walled parts Install incremental forming tools on the robots on both sides of the metal sheet. According to the thickness and strength of the metal sheet, set the step depth, forming tools and forming trajectory (4) of double-sided incremental forming. Through the robots, control the incremental forming tools to perform double-sided extrusion forming on the metal sheet according to the forming trajectory (4) and forming process parameters under the predetermined temperature condition, so that the shape of the thin-walled part conforms to the predetermined requirements; S300 Rolling surface treatment of thin-walled parts Install rolling tools on the robots on both sides, set the row spacing, rolling pressure (10) and rolling trajectory (9) of the rolling treatment. Through the robots, control the rolling tools to roll the two sides of the thin-walled part a set number of times according to the rolling trajectory (9) and rolling process parameters under the predetermined temperature condition, so as to improve the surface performance of the thin-walled part to meet the predetermined requirements; S400 Mirror milling of thin-walled parts Install a mirror milling combination tool on the robot, set the row spacing, feed rate and machining trajectory of the mirror milling. Through the robot, control the mirror milling tool to machine the thin-walled part, so that the thickness and size of the part meet the predetermined requirements.

2. The one-piece machining method according to claim 1, characterized in that: The frame fixture (1) includes a front frame and a back frame, and clamps the metal sheet on both sides thereof.

3. The one-piece processing method according to claim 1, characterized in that: The incremental forming tools include a fixed ball head forming tool (2), a rolling ball head forming tool (5) and a disc forming tool (6), and the material of the incremental forming tools is cemented carbide, steel or ceramic.

4. The one-piece processing method according to claim 1, characterized in that: The forming trajectory (4) is a single-pass forming trajectory or a multi-pass forming trajectory.

5. The one-piece machining method according to claim 1, wherein: The predetermined temperature condition in the incremental forming process includes: room temperature environment or a high temperature environment created by self-resistance heating of the incremental forming tools by a DC power supply (7).

6. The one-piece processing method according to claim 1, wherein: The rolling tools include a fixed ball head rolling tool (8) and a rolling ball head rolling tool (11).

7. The integrated processing method according to claim 1, characterized in that: The rolling tools achieve the set output rolling pressure (10) through a pneumatic system, a hydraulic system or an electric system.

8. The one-piece processing method according to claim 1, characterized in that: The predetermined temperature condition in the rolling process includes: room temperature environment or a low temperature environment created by spraying liquid nitrogen from a liquid nitrogen nozzle (12).

9. The integrated processing method according to claim 1, wherein: The mirror milling combination tool includes a motorized spindle (13) installed on one side robot and a support disk (14) installed on the other side robot. A milling cutter is installed on the motorized spindle to machine from one side, and the support disk is installed on the other side robot for support.

10. The one-piece processing method according to claim 1, wherein: Mirror milling includes machining of the metal thin-walled part, including: local thinning, trimming or hole making.

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