Aluminum alloy forming process based on 3D printing stamping die

Abstract

The invention provides an aluminum alloy forming process based on a 3D printing stamping die, and the aluminum alloy forming process comprises the following steps: step S1, the 3D printing stamping die is mounted on a stamping machine table, and a die waterway is communicated with cooling water; s2, the aluminum alloy plate blank is heated; s3, the aluminum alloy plate blank is moved to a stamping die to be subjected to stamping forming, and pressure maintaining is conducted after forming; s4, taking out the thermoforming part and carrying out overaging heat treatment; and S5, the aluminum alloy part is obtained through cooling. The aluminum alloy forming process based on the 3D printing stamping die has the advantages of being high in production efficiency, low in cost and good in comprehensive performance of manufactured aluminum alloy materials, the requirement for batch production can be met, manufactured aluminum alloy part materials have high strength and stress corrosion resistance, and the requirement of aircrafts for the comprehensive performance of the materials is met.

Description

Technical Field

[0001] This invention relates to the field of material forming technology, and more specifically, to an aluminum alloy forming process based on 3D printed stamping dies. Background Technology

[0002] With the development of the aviation and automotive industries, there are increasingly higher requirements for the reliability, strength, production efficiency, and cost of materials. 7075-T76 aluminum alloy sheet metal parts have high strength and good resistance to stress corrosion, and are widely used in aircraft structural components.

[0003] Traditional aerospace industry production of 7-series aluminum alloy sheet metal parts is characterized by low efficiency and high cost. The traditional aerospace industry's 7-series aluminum alloy forming process primarily employs cold stamping followed by solution and aging heat treatment. The solution and heat treatment process causes part deformation, requiring manual straightening to maintain dimensional accuracy, resulting in low manufacturing efficiency and high costs.

[0004] The automotive industry uses hot forming processes to manufacture 7075 aluminum alloy parts. However, due to the limitations of CNC (Computer Numerical Control) mold manufacturing processes, the cooling water channels are mostly straight pipes, which cannot be manufactured according to the shape and cannot be evenly distributed. This limits the effect of solution heat treatment of aluminum alloys and fails to maximize the performance advantages of aerospace 7-series aluminum alloys.

[0005] In view of this, the present invention is hereby proposed. Summary of the Invention

[0006] The purpose of this invention is to address the shortcomings of existing technologies by providing an aluminum alloy forming process based on 3D printing stamping dies. This process has the advantages of high production efficiency, low cost, and good comprehensive performance of the manufactured aluminum alloy materials. It can meet the needs of mass production, and the manufactured aluminum alloy parts have high strength and stress corrosion resistance, thus meeting the comprehensive performance requirements of aircraft materials.

[0007] In order to achieve the above-mentioned objectives of the present invention, the following technical solution is adopted: An aluminum alloy forming process based on 3D printed stamping dies includes the following steps: Step S1: Mount the 3D printed stamping mold onto the stamping machine, and connect the mold's water circuit to the cooling water supply. Step S2: Heat the aluminum alloy sheet blank; Step S3: Transfer the aluminum alloy sheet blank to the stamping die for stamping and forming, and hold the pressure after forming; Step S4: Remove the thermoformed part and perform an aging heat treatment; Step S5: Cooling to obtain aluminum alloy parts.

[0008] Furthermore, the 3D printing stamping die manufacturing method in step S1 includes: step S1.1, designing the three-dimensional configuration of the stamping die according to the shape of the aluminum alloy part; step S1.2, manufacturing the stamping die by metal 3D printing according to the three-dimensional configuration of the stamping die.

[0009] Furthermore, in step S1.1, the water channel of the stamping die is designed as a conformal water channel, the surface quality of the inner wall of the water channel reaches Ra12.5, and the cooling rate is >200℃ / S.

[0010] Furthermore, the thickness of the aluminum alloy sheet blank in step S2 is 0.5~3mm.

[0011] Further, in step S2, the aluminum alloy sheet blank is uniformly heated to 470~490°C for 10min~20min.

[0012] Furthermore, in step S3, the aluminum alloy sheet blank is taken out of the heating furnace and quickly transferred to the stamping die, with a time interval of <15s from exiting the furnace to stamping.

[0013] Furthermore, in step S3, the temperature of the aluminum alloy sheet blank when it moves above the stamping die is 450~490°C.

[0014] Furthermore, in step S3, the holding time after stamping is not less than 20 seconds.

[0015] Furthermore, the over-aging heat treatment in step S4 is a segmented over-aging heat treatment, including a first stage and a second stage. The first stage is held at 120~130°C for 3~6 hours, and the second stage is held at 160~170°C for 10~25 hours.

[0016] Further, in step S5, the aluminum alloy part is obtained by air cooling to room temperature.

[0017] Compared with the prior art, the beneficial effects of the present invention are as follows: 1. This invention relates to an aluminum alloy forming process based on 3D-printed stamping dies. It utilizes a high-efficiency conformal water-channel stamping die manufactured using 3D printing technology. The aluminum alloy sheet blank is heated and then transferred to the 3D-printed stamping die for forming. The forming and solution heat treatment processes are simultaneously completed within the stamping die, which features conformal water channels, significantly improving the formability and production efficiency of high-performance aluminum alloy materials. After hot forming, the parts undergo over-aging heat treatment. This combination of hot forming and over-aging heat treatment achieves a high strength and excellent corrosion resistance. The entire aluminum alloy forming process of this invention is characterized by high efficiency and low cost. The manufactured aluminum alloy parts possess high strength and resistance to stress corrosion, meeting the comprehensive material performance requirements of aircraft.

[0018] 2. This invention utilizes 3D printing technology to manufacture stamping dies. Based on this technology, complex conformal cooling water systems can be created. These conformal water channels can be evenly and widely distributed below the surface of the stamping die, improving its cooling efficiency. Heating the aluminum alloy sheet blank and rapidly transferring it to the stamping die significantly improves the formability of the aluminum alloy material. Simultaneously, the 3D-printed stamping die design with conformal water channels ensures sufficient cooling rate and uniformity. This improved cooling efficiency ensures thorough solution treatment of the aluminum alloy, resulting in better heat treatment effects and enhanced material properties of the final aluminum alloy parts. Further post-forming aging heat treatment yields superior overall material properties.

[0019] 3. The aluminum alloy forming process based on 3D printing stamping dies of this invention also has the advantages of high production efficiency, low cost and good comprehensive performance, which meets the needs of mass production. Attached Figure Description

[0020] To more clearly illustrate the specific embodiments of the present invention or the technical solutions in the prior art, the drawings used in the description of the specific embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of the present invention. For those skilled in the art, other drawings can be obtained from these drawings without creative effort.

[0021] Figure 1 This is a schematic diagram of the internal structure of a stamping die with conformal water channels for 3D printing according to the present invention. Detailed Implementation

[0022] The technical solution of the present invention will be clearly and completely described below with reference to specific embodiments. However, those skilled in the art will understand that the embodiments described below are some embodiments of the present invention, but not all embodiments, and are only used to illustrate the present invention, and should not be regarded as limiting the scope of the present invention. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention. Where specific conditions are not specified in the embodiments, conventional conditions or conditions recommended by the manufacturer shall be followed. Where the manufacturers of reagents or instruments are not specified, they are all conventional products that can be purchased commercially.

[0023] An aluminum alloy forming process based on 3D printed stamping dies includes the following steps: Step S1: Mount the 3D printed stamping mold onto the stamping machine, and connect the mold's water circuit to the cooling water supply. Step S2: Heat the aluminum alloy sheet blank; Step S3: Transfer the aluminum alloy sheet blank to the stamping die for stamping and forming, and hold the pressure for a period of time after forming; Step S4: Remove the thermoformed part and perform an aging heat treatment; Step S5: Cooling to obtain aluminum alloy parts.

[0024] Preferably, the 3D printing stamping die manufacturing method in step S1 includes: step S1.1, designing the three-dimensional configuration of the stamping die according to the shape of the aluminum alloy part; step S1.2, manufacturing the stamping die by metal 3D printing according to the three-dimensional configuration of the stamping die.

[0025] This invention manufactures thermoforming stamping dies with conformal water channels using 3D printing technology. Metal 3D printing technology provides a very high degree of freedom for die design, and complex die structures with conformal water channels can be designed according to the shape of the part through 3D printing.

[0026] Preferably, the water channel of the stamping die designed in step S1.1 is a conformal water channel, such as... Figure 1 As shown, cooling water channels are designed to follow the shape and be distributed below the forming surface of the part to ensure that the surface of each part has a uniform cooling efficiency. Under the premise of ensuring the strength requirements of the mold, the cooling water channels are made as close as possible to the surface of the mold cavity.

[0027] Preferably, in step S1.2, mold steel material is used to manufacture a stamping mold with conformal water channels by metal 3D printing. 3D printing can ensure that the surface quality of the inner wall of the water channel reaches Ra12.5, so as to ensure that the cooling water channel is unobstructed during the aluminum alloy forming process, the cooling rate is >200℃ / S, and sufficient cooling efficiency can be achieved to obtain good aluminum alloy parts material properties.

[0028] This invention improves the cooling efficiency of the forming process by 3D printing a stamping die with conformal water channels, ensuring more complete solid solution of the material, guaranteeing the performance of aluminum alloy materials, and improving material uniformity.

[0029] The conformal cooling water channels of the 3D printing stamping die of this invention can be evenly distributed below the entire surface of the part die. The improved cooling efficiency is beneficial to improving the strength of aluminum alloy materials. The high cooling efficiency provides the prerequisite for the full solid solution of aluminum alloy materials during the forming process, ensuring the material properties and uniformity of the final aluminum alloy parts.

[0030] Preferably, in step S1, the mold water circuit is connected to cooling water to control the mold temperature to ≤15℃, which meets the process requirements.

[0031] Preferably, the thickness of the aluminum alloy sheet blank in step S2 is 0.5~3mm, including but not limited to 0.5mm, 1mm, 1.5mm, 2mm, 2.5mm, and 3mm.

[0032] Preferably, in step S2, the aluminum alloy sheet blank is uniformly heated to 470~490℃, including but not limited to 470℃, 475℃, 480℃, 485℃, and 490℃. The aluminum alloy sheet blank of this invention is heated and then formed, and the part forming and solution heat treatment processes are simultaneously completed in a 3D printing stamping die equipped with conformal water channels, greatly improving the formability and production efficiency of high-performance aluminum alloy materials.

[0033] Preferably, the heating process of the aluminum alloy sheet billet in step S2 is as follows: the furnace temperature is raised to 470~490℃ (including but not limited to 470℃, 475℃, 480℃, 485℃, 490℃), the aluminum alloy sheet billet is placed in the furnace for heating, and the heating time is 10min~20min (including but not limited to 10min, 12min, 14min, 16min, 18min, 20min) to ensure that the aluminum alloy sheet billet reaches the target temperature range and is held at that temperature for a sufficient time, so that the surface and internal temperature of the aluminum alloy sheet billet are uniform.

[0034] Preferably, in step S3, a release agent is sprayed onto the mold for lubrication before stamping.

[0035] Preferably, in step S3, the aluminum alloy sheet blank is taken out from the heating furnace and quickly transferred to the stamping die. The time interval from exiting the furnace to stamping is <15s, so that the temperature of the aluminum alloy sheet blank when it moves above the stamping die is 450~490°C and the temperature drop is no more than 20°C.

[0036] Preferably, in step S3, the stamping process is performed rapidly, and the pressure holding time after stamping is not less than 20 seconds.

[0037] Preferably, the over-aging heat treatment in step S4 is a segmented over-aging heat treatment, including a first stage and a second stage. The first stage is to hold at 120~130℃ for 3~6h (including but not limited to 3h, 4h, 5h, 6h), and the second stage is to hold at 160~170℃ (including but not limited to 160℃, 161℃, 162℃, 163℃, 164℃, 165℃, 166℃, 167℃, 168℃, 169℃, 170℃) for 10~25h (including but not limited to 10h, 15h, 20h, 25h).

[0038] This invention simultaneously completes the thermoforming and solution heat treatment processes of parts within a 3D-printed stamping die with conformal water channels. Combined with a segmented over-aging heat treatment process, the aluminum alloy parts exhibit excellent comprehensive properties, possessing both high mechanical strength and corrosion resistance.

[0039] Preferably, the over-aging heat treatment in step S4 is an artificial over-aging heat treatment. In the first stage, the aging furnace is heated to 120~130℃ (including but not limited to 120℃, 121℃, 122℃, 123℃, 124℃, 125℃, 126℃, 127℃, 128℃, 129℃, and 130℃). After reaching the set temperature, the thermoformed part at room temperature is placed in the aging furnace for heating. Timing begins after the furnace temperature returns to the set temperature. Before the aging furnace reaches the set temperature, the temperature should be increased slowly to avoid localized overheating. The first stage of heat preservation time is 3~6 hours (including but not limited to 3 hours, 4 hours, 5 hours, and 6 hours); in the second stage, the aging furnace is heated to 160~170℃ (including but not limited to 160℃, 161℃, 162℃, 163℃, 164℃, 165℃, 166℃, 167℃, 168℃, 169℃, and 170℃). The temperature should be increased slowly to avoid local overheating or increased internal stress. Once the set temperature is reached, the timer starts, and the heat preservation time is 10~25 hours (including but not limited to 10 hours, 15 hours, 20 hours, and 25 hours).

[0040] Preferably, in step S5, the aluminum alloy part is obtained by air cooling to room temperature.

[0041] Example 1 An aluminum alloy forming process based on 3D printed stamping dies, the process route is: blanking—heating of sheet metal blank—stamping—aging heat treatment, specifically including the following steps: 1. Mount the 3D printed stamping mold onto the stamping machine, and connect the mold's water passage to the cooling water supply. 2. Place the 2.0mm thick 7075 aluminum alloy sheet blank into the furnace and heat it to 480℃ for 15 minutes; 3. Transfer the aluminum alloy sheet blank to the stamping die for stamping and forming, and hold the pressure for 30 seconds after forming; 4. Remove the thermoformed parts and perform segmented aging heat treatment. The first stage is held at 120℃ for 4 hours, and the second stage is held at 165℃ for 21 hours. 5. Cooling yields aluminum alloy parts.

[0042] Example 2 An aluminum alloy forming process based on 3D printed stamping dies, the process route is: blanking—heating of sheet metal blank—stamping—aging heat treatment, specifically including the following steps: 1. Mount the 3D printed stamping mold onto the stamping machine, and connect the mold's water passage to the cooling water supply. 2. Place a 1mm thick 7075 aluminum alloy sheet blank into the furnace and heat it to 470℃ for 10 minutes; 3. Transfer the aluminum alloy sheet blank to the stamping die for stamping and forming, and hold the pressure for 20 seconds after forming; 4. Remove the thermoformed parts and perform segmented aging heat treatment. The first stage is held at 120℃ for 3 hours, and the second stage is held at 160℃ for 20 hours. 5. Cooling yields aluminum alloy parts.

[0043] Example 3 An aluminum alloy forming process based on 3D printed stamping dies, the process route is: blanking—heating of sheet metal blank—stamping—aging heat treatment, specifically including the following steps: 1. Mount the 3D printed stamping mold onto the stamping machine, and connect the mold's water passage to the cooling water supply. 2. Place a 3mm thick 7075 aluminum alloy sheet blank into the furnace and heat it to 490℃ for 20 minutes; 3. Transfer the aluminum alloy sheet blank to the stamping die for stamping and forming, and hold the pressure for 30 seconds after forming; 4. Remove the thermoformed parts and perform segmented aging heat treatment. The first stage is held at 120℃ for 6 hours, and the second stage is held at 170℃ for 15 hours. 5. Cooling yields aluminum alloy parts.

[0044] Comparative Example 1 An aluminum alloy forming process based on stamping dies, the process route is: blanking—heating of sheet metal blank—stamping—aging heat treatment, specifically including the following steps: 1. Install the traditional stamping die on the stamping machine, and connect the die water channel to the cooling water. 2. Place the 2.0mm thick 7075 aluminum alloy sheet blank into the furnace and heat it to 480℃ for 15 minutes; 3. Transfer the aluminum alloy sheet blank to the stamping die for stamping and forming, and hold the pressure for 30 seconds after forming; 4. Remove the thermoformed parts and perform segmented aging heat treatment. The first stage is held at 120℃ for 4 hours, and the second stage is held at 165℃ for 21 hours. 5. Cooling yields aluminum alloy parts.

[0045] Comparative Example 2 An aluminum alloy forming process based on 3D printed stamping dies, the process route is: blanking—heating of sheet metal blank—stamping—aging heat treatment, specifically including the following steps: 1. Mount the 3D printed stamping mold onto the stamping machine, and connect the mold's water passage to the cooling water supply. 2. Place the 2.0mm thick 7075 aluminum alloy sheet blank into the furnace and heat it to 480℃ for 15 minutes; 3. Transfer the aluminum alloy sheet blank to the stamping die for stamping and forming, and hold the pressure for 30 seconds after forming; 4. Remove the thermoformed parts and perform an aging heat treatment, holding at 130℃ for 18 hours; 5. Cooling yields aluminum alloy parts.

[0046] Test case Five samples were taken from different locations on the surface of the aluminum alloy parts manufactured in Examples 1-3 and Comparative Examples 1-2, and tensile and electrical conductivity tests were performed. The test results are shown in Tables 1-5.

[0047] Table 1 Performance test results of aluminum alloy parts manufactured in Example 1

[0048] Table 2 Performance test results of aluminum alloy parts manufactured in Example 2

[0049] Table 3 Performance test results of aluminum alloy parts manufactured in Example 3

[0050] Table 4 Performance test results of aluminum alloy parts manufactured in Comparative Example 1

[0051] Table 5 Performance test results of aluminum alloy parts manufactured in Comparative Example 2

[0052] As shown in Tables 1-5, the aluminum alloy parts manufactured in Examples 1-3 using the 3D printing stamping die-based aluminum alloy forming process of this invention achieved high mechanical properties, and the electrical conductivity (%IACS) was greater than 38, indicating that the manufactured 7075 aluminum alloy parts had reached the T76 state and had good stress corrosion resistance. The final manufactured 7075 aluminum alloy parts had good overall performance, with minimal performance differences between different locations and good uniformity. In Comparative Example 1, due to the use of traditional stamping dies, the cooling rate and uniformity were insufficient, resulting in a decrease in the mechanical properties of the manufactured 7075 aluminum alloy parts, a large performance difference between different locations, and poor uniformity. In Comparative Example 2, due to the use of a single-stage over-aging treatment, the single temperature resulted in incomplete precipitation or slow kinetics, affecting the precipitation of supersaturated alloying elements from the aluminum matrix, deteriorating the electrical conductivity and mechanical properties of the aluminum alloy parts, and reducing overall performance.

Claims

1. An aluminum alloy forming process based on 3D printed stamping dies, characterized in that, Includes the following steps: Step S1: Mount the 3D printed stamping mold onto the stamping machine, and connect the mold's water circuit to the cooling water supply. Step S2: Heat the aluminum alloy sheet blank; Step S3: Transfer the aluminum alloy sheet blank to the stamping die for stamping and forming, and hold the pressure after forming; Step S4: Remove the thermoformed part and perform an aging heat treatment; Step S5: Cooling to obtain aluminum alloy parts.

2. The aluminum alloy forming process based on 3D printed stamping dies according to claim 1, characterized in that, The 3D printing stamping die manufacturing method in step S1 includes: step S1.1, designing the three-dimensional configuration of the stamping die according to the shape of the aluminum alloy part; step S1.2, manufacturing the stamping die by metal 3D printing according to the three-dimensional configuration of the stamping die.

3. The aluminum alloy forming process based on 3D printed stamping dies according to claim 2, characterized in that, In step S1.1, the water channel of the stamping die is designed as a conformal water channel, the surface quality of the inner wall of the water channel reaches Ra12.5, and the cooling rate is >200℃ / S.

4. The aluminum alloy forming process based on 3D printed stamping dies according to claim 1, characterized in that, The thickness of the aluminum alloy sheet blank in step S2 is 0.5~3mm.

5. The aluminum alloy forming process based on 3D printed stamping dies according to claim 4, characterized in that, In step S2, the aluminum alloy sheet blank is uniformly heated to 470~490°C for 10min~20min.

6. The aluminum alloy forming process based on 3D printed stamping dies according to claim 1, characterized in that, In step S3, the aluminum alloy sheet blank is taken out of the heating furnace and quickly transferred to the stamping die, with a time interval of <15s from exiting the furnace to stamping.

7. The aluminum alloy forming process based on 3D printed stamping dies according to claim 5, characterized in that, In step S3, the temperature of the aluminum alloy sheet blank when it moves above the stamping die is 450~490°C.

8. The aluminum alloy forming process based on 3D printed stamping dies according to claim 6 or 7, characterized in that, In step S3, the holding time after stamping is not less than 20 seconds.

9. The aluminum alloy forming process based on 3D printed stamping dies according to claim 1, characterized in that, The over-aging heat treatment in step S4 is a segmented over-aging heat treatment, including a first stage and a second stage. The first stage is held at 120~130°C for 3~6 hours, and the second stage is held at 160~170°C for 10~25 hours.

10. The aluminum alloy forming process based on 3D printed stamping dies according to claim 1, characterized in that, In step S5, the aluminum alloy part is obtained by air cooling to room temperature.

Images