Method and device for manufacturing copper and copper alloy through electric arc fuse additive material by dynamically regulating and controlling heat input in layer

Abstract

The invention relates to a method and a device for manufacturing copper and copper alloy through an electric arc fuse additive material by dynamically regulating and controlling heat input in a layer, which comprises the following steps: monitoring the temperature on line, monitoring the temperature of an arcing position at the beginning of each deposition, and starting the additive material manufacturing when the temperature is within a set range; in the arcing stage, large heat input is adopted to guarantee arcing, additional material interruption caused by the wire sticking fault is avoided, and after a molten pool is stably formed, heat input is gradually reduced; in the middle stable section of deposition, medium heat input is used, the stable size of a molten pool is maintained, and it is ensured that a deposition layer has enough melting width and a proper deposition angle; in the deposition arc quenching stage, electric arc heat input is rapidly reduced, and melting collapse of the deposition tail end caused by an overlarge molten pool formed by heat accumulation is avoided; depositing layer by layer to prepare copper and copper alloy components with good morphology; according to the method, the copper and copper alloy component which is provided with a flat deposition layer, free of collapse and good in stacking morphology can be prepared, the material utilization rate is increased, and the geometric accuracy of high-thermal-conductivity copper and copper alloy products is improved.

Description

Technical Field

[0001] The present invention belongs to the technical field of metal additive manufacturing, and specifically relates to a method and device for additive manufacturing of copper and copper alloys by arc fuses with dynamically controlled heat input within a layer. Background Art

[0002] Copper and copper alloys are widely used in railway transportation, aerospace, national defense and military industries due to their excellent electrical and thermal conductivity, good plasticity and corrosion resistance. With the increasing demand for copper and copper alloys in many fields, traditional methods of manufacturing copper and copper alloy components are facing problems such as high production costs and long manufacturing cycles. Metal additive manufacturing technology, as an advanced manufacturing method, based on the principle of "layer-by-layer stacking", can achieve the integrated manufacturing of complex structural parts that are difficult to manufacture with traditional processing methods. Arc fuse additive manufacturing, as a metal additive manufacturing technology, uses an arc heat source to melt metal wire and deposits metal along a predetermined trajectory to form a dense part. It has the characteristics of high deposition efficiency and low production cost, especially in the manufacture of large-size and complex structural components. It shows its unique advantages.

[0003] However, in practical applications, due to the high thermal conductivity of copper and copper alloys, especially materials such as pure copper (401W / (m·K)) and chromium zirconium copper (323W / (m·K)), arc fuse additive manufacturing faces certain challenges. The high thermal conductivity of the material makes the molten pool size very sensitive to heat accumulation. During the arc fuse additive manufacturing process, the arc heat source is constantly moving, the arc is frequently started and extinguished, and the heat accumulation state is constantly changing. Existing methods for arc-fuse additive manufacturing of copper and copper alloys ([1]: Poonam S. Deshmukh, Krishna Tomar, G. Dan Sathiaraj, et al. Optimum strength and ductility of pure copper fabricated by Wire Arc Additive Manufacturing[J]. Manufacturing Letters, 2022, 33: 24-28. https: / / doi.org / 10.1016 / j.mfglet.2022.06.005; [2]: Bunty Tomar, S. Shiva. Microstructural and mechanical properties examination of SS316L-Cu functionally graded material fabricated by wire arc additive manufacturing[J]. CIRP Journal of Manufacturing Science and Engineering Technology, 2024, 50: 26-39. https: / / doi.org / 10.1016 / j.cirpj.2024.02.002) maintains a constant heat input, which cannot adapt to the dynamic changes of heat accumulation, leading to defects such as poor stacking morphology, collapse and low material utilization.

[0004] Therefore, in the arc fuse additive manufacturing process, it is difficult to meet the additive needs of high thermal conductivity copper and copper alloys using a constant heat input mode. In order to ensure high-quality products, the heat input must be precisely controlled during the additive process. Due to the high thermal conductivity of the material, heat will be conducted rapidly, and the temperature of the deposited part will change continuously. It is necessary to dynamically adjust the heat input during the additive process to adapt to the temperature changes at the deposition position and achieve precise control of the molten pool size. Avoid unreasonable heat input leading to problems such as poor deposition morphology, collapse, and low material utilization. Therefore, exploring and studying additive strategies for dynamic control of heat input for high thermal conductivity copper and copper alloys is the key to improving manufacturing quality and reducing production costs. No relevant literature has been published yet. Summary of the invention

[0005] In order to overcome the shortcomings of the above-mentioned prior art, the purpose of the present invention is to provide a method and device for additively manufacturing copper and copper alloys by arc fuse with dynamic control of heat input within a layer, which can prepare copper and copper alloy components with a smooth deposition layer, no collapse and good deposition morphology, improve material utilization, and enhance the geometric accuracy of high thermal conductivity copper and copper alloy products.

[0006] In order to achieve the above objectives, the present invention adopts the following technical solutions:

[0007] A method for additively manufacturing copper and copper alloys by arc fuse with dynamically controlled heat input within a layer. The method monitors the temperature online and monitors the temperature of the arc starting position at the beginning of each deposition. When the temperature is within the set range, additive manufacturing begins. In the arc starting stage, large heat input is used to ensure arc starting to avoid "wire sticking failure" that causes interruption of additive manufacturing. After the molten pool is stably formed, the heat input is gradually reduced. In the middle stable section of deposition, medium heat input is used to maintain a stable molten pool size to ensure that the deposited layer has sufficient molten width and a suitable cladding angle. In the arc extinguishing stage of deposition, the arc heat input is quickly reduced to avoid heat accumulation to form an excessively large molten pool, which causes melting collapse at the end of deposition. Copper and copper alloy components with good morphology are prepared by deposition layer by layer.

[0008] A method for additively manufacturing copper and copper alloys with arc fuses with dynamic control of heat input within a layer, comprising the following steps:

[0009] Step 1: Use a heating plate to preheat the substrate until the surface temperature of the substrate reaches above 130°C, then stop preheating;

[0010] Step 2: Use an infrared pyrometer to monitor the temperature of the arc starting position online. When the temperature is within the range of 120°C-130°C, start additive manufacturing; when the temperature is lower than 120°C, use a hot air gun to heat the arc starting position;

[0011] Step 3: Under the constant heat input mode, multiple groups of single-pass additive experiments are carried out, and the heat input power corresponding to the group with the best weld bead morphology is selected and set as the standard power;

[0012] Step 4: Dynamically adjust the heat input during the deposition process, select the heat input adjustment variable during the additive process, and change the adjustment variable during the deposition process to control the heat input according to the corresponding relationship between the adjustment variable and the heat input power; in the arc starting stage, use high heat input (more than 110% of the standard power) to start the arc, and gradually reduce the heat input after the molten pool is stably formed; when entering the intermediate stable stage, use medium heat input (105% to 95% of the standard power), and control the heat input during the deposition process according to the set program, so that the deposited layer has sufficient melt width and suitable deposition angle; in the arc extinguishing stage, quickly reduce the heat input (less than 80% of the standard power) to avoid collapse caused by excessive molten pool, and thus complete one additive deposition;

[0013] Step 5, repeating steps 2 and 4 in sequence, adding material layer by layer, and finally forming a deposited part;

[0014] Step 5: Remove the deposited part, cut the additively formed part from the substrate using an electric spark discharge cutting machine, and observe and evaluate the formed morphology.

[0015] The adjustment variables in step 4 include wire feeding speed, deposition moving speed or CMT / P balance coefficient, and a single variable or multiple variables are selected to coordinately realize dynamic regulation of heat input.

[0016] The step 4 dynamically adjusts the heat input during the deposition process throughout each additive deposition process from arc starting to arc extinction.

[0017] A device used in an arc fuse additive manufacturing method for copper and copper alloys with dynamically controlled heat input within a layer, comprising an additive platform 9, a heating plate 8 placed on the additive platform 9, the heating plate 8 connected to a temperature controller 7, a substrate 1 placed on the heating plate 8, a deposited formed part 2 on the substrate 1, a welding gun 3 provided above the deposited formed part 2, the welding gun 3 connected to a welding machine 10 and an argon gas bottle 11; an infrared pyrometer 4 is provided next to the deposited formed part 2, the signal output of the infrared pyrometer 4 is connected to a signal input end of a computer 5, the signal output end of the computer 5 is connected to a signal input end of a control box 6, and the output end of the control box 6 is connected to the control end of the additive platform 9 and the welding machine 10.

[0018] Compared with the prior art, the present invention has the following beneficial effects:

[0019] (A) The present invention monitors the temperature of the arc starting position of each deposition process online and starts additive manufacturing when the temperature is within a preset temperature range. Compared with the traditional cooling method that adopts a fixed interlayer cooling time, the present invention can ensure the consistency of the interlayer temperature during each additive manufacturing process and avoid the influence of the interlayer temperature as an experimental variable on the experimental results.

[0020] (B) The present invention monitors the temperature of the arc starting position in real time and dynamically adjusts the interlayer waiting time. Compared with the cooling method that adopts a fixed interlayer cooling time, it avoids unnecessary waiting time and effectively improves the efficiency of arc fuse additive manufacturing.

[0021] (C) The present invention adopts a deposition strategy of dynamically controlling heat input, accurately controlling the heat input in each deposition process, and adjusting the heat accumulation state. Compared with the traditional constant heat input additive method, it can effectively avoid the generation of morphological defects and prepare copper and copper alloy components with good morphology.

[0022] (D) The deposition method for dynamically controlling heat input proposed in the present invention has strong scalability and can be used as a reference for arc fuse additive manufacturing of other high thermal conductivity materials. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] Figure 1 Schematic diagram of the device used in the method for additively manufacturing copper and copper alloys using arc fuses with dynamically controlling heat input within a layer in Example 1.

[0024] Figure 2 This is the single-pass additive deposition experiment with constant heat input in Example 1.

[0025] Figure 3 Schematic diagram of the heat input adjustment change curve in Example 1.

[0026] Figure 4 Comparison of deposition morphologies of chromium-zirconium-copper in additive manufacturing with different heat input modes; (a) is the constant heat input mode of the additive process - insufficient heat input; (b) is the constant heat input mode of the additive process - excessive heat input; (c) is the dynamic heat input adjustment mode of the additive process in Example 1.

[0027] Figure 5 This is the morphology of pure copper deposition produced by additive manufacturing in Example 2.

[0028] In the figure: 1 is a substrate; 2 is a deposited part; 3 is a welding gun; 4 is an infrared pyrometer; 5 is a computer; 6 is a control box; 7 is a temperature controller; 8 is a heating plate; 9 is an additive platform; 10 is a welding machine; and 11 is an argon gas bottle. DETAILED DESCRIPTION

[0029] The present invention is described in detail below in conjunction with embodiments and drawings.

[0030] Example 1: Figure 1As shown, a device used in an arc fuse additive manufacturing method for copper and copper alloys with dynamically controlled heat input within a layer includes an additive platform 9, a heating plate 8 is placed on the additive platform 9, the heating plate 8 is connected to a temperature controller 7, a substrate 1 is placed on the heating plate 8, a deposited formed part 2 is placed on the substrate 1, a welding gun 3 is arranged above the deposited formed part 2, the welding gun 3 is connected to a welding machine 10 and an argon gas bottle 11; an infrared pyrometer 4 is arranged next to the deposited formed part 2, the signal output of the infrared pyrometer 4 is connected to the signal input end of a computer 5, the signal output end of the computer 5 is connected to the signal input end of a control box 6, and the output end of the control box 6 is connected to the control end of the additive platform 9 and the welding machine 10.

[0031] A method for manufacturing copper and copper alloys by adding arc fuses with dynamic control of heat input within a layer, comprising the following steps:

[0032] (1) Select a Q235 steel substrate, and use a clamp to fix the substrate 1 on the additive platform 9; use a grinder to grind the surface of the substrate 1, and use alcohol to clean the surface to remove oil stains, and then dry the surface; select a 1.2 mm diameter chromium-zirconium-copper (CuCrZr) alloy welding wire as a deposition material;

[0033] (2) Set the parameters related to arc fuse additive:

[0034] Open the 99.99% pure argon gas channel and set the flow rate to 20L / min; select the CMT+P mode of the unified welding mode for additive mode, set the wire feeding speed to 7m / min, and the welding moving speed to 0.4m / min;

[0035] Prepare a single wall with dimensions of 120 mm long and 80 mm high, using a reciprocating alternating deposition path, and input the path program code into the arc additive robot control panel;

[0036] The CMT / P balance coefficient is selected as the variable for adjusting the heat input in the additive process, and a curve is set for its change over time. The program controls the variable to change according to the curve. The arc starts when the deposition is started, and the arc ends when the deposition is stopped.

[0037] (3) Preheating the substrate 1, starting the temperature controller 7 to energize the heating plate 8 for heating, and when the surface temperature of the substrate 1 reaches above 130° C., turning off the temperature controller 7 to stop heating;

[0038] (4) Using an infrared pyrometer 4 to monitor the temperature of the arc starting position, when the temperature is within the range of 120°C-130°C, start the additive manufacturing; when the temperature is lower than 120°C, use a hot air gun to heat the arc starting position until the temperature rises to the set range;

[0039] (5) Under the constant heat input mode, multiple groups of single-pass additive experiments are carried out, and the heat input power corresponding to the group with the best weld bead morphology is selected and set as the standard power; Figure 2 As shown; observing the morphology of single-pass forming, the weld bead with a heat input power of 4239W is evenly spread, there is no obvious collapse at the arc extinguishing point, and the morphology is optimal, so 4239W is selected as the standard power;

[0040] (6) Dynamically adjust the heat input during the deposition process, select the heat input adjustment variable (wire feeding speed, deposition moving speed or CMT / P balance coefficient, etc.) during the additive process, and change the adjustment variable to control the heat input during the deposition process according to the corresponding relationship between the adjustment variable and the heat input power; in the arc starting stage, use high heat input (more than 110% of the standard power) to start the arc, and gradually reduce the heat input after the molten pool is stably formed; when entering the intermediate stable stage, use medium heat input (105% to 95% of the standard power), and control the heat input during the deposition process according to the set program, so that the deposited layer has sufficient melt width and appropriate deposition angle; in the arc extinction stage, quickly reduce the heat input (less than 80% of the standard power) to avoid collapse caused by excessive molten pool;

[0041] In this embodiment, the standard power is set according to step (5), the heat input power is 5086W when the arc is started, the heat input in the middle section is reduced from 4451W to 4027W, and the heat input is 2967W when the arc is extinguished; the CMT / P balance coefficient is selected as the heat input adjustment variable in the additive process. According to the corresponding relationship between power and CMT / P balance coefficient, the CMT / P balance coefficient changes with time during the deposition process. The corresponding heat input adjustment change curve is as follows: Figure 3 As shown;

[0042] (7) Additive manufacturing is performed. According to a predetermined program, the arc starting and heat input control program of the welding gun 3 are started simultaneously. During the deposition process, the welding gun 3 moves along a set trajectory to deposit metal, and adjusts the heat input according to the heat input adjustment curve. When the arc is extinguished, the arc is extinguished and the heat input control program of the welding gun 3 is terminated simultaneously, thereby completing an additive deposition.

[0043] (8) Repeating steps (4) and (7) sequentially, performing additive deposition layer by layer, until the entire deposited formed part 2 is manufactured;

[0044] (9) The deposited formed part 2 is cut from the substrate 1 using an electric spark discharge cutting machine, and the formed morphology is observed and analyzed, and compared with the deposition result of the fixed heat input mode.

[0045] Reference Figure 4 , Figure 4 Comparison of deposition morphologies of chromium-zirconium-copper additively manufactured under different heat input modes; Figure 4(a) is the deposition result of low heat input in constant heat input mode. When the arc is started, due to the high thermal conductivity of chromium-zirconium copper, the heat will diffuse rapidly, and the molten pool is difficult to form and maintain stably. Frequent "wire sticking failure" errors occur, resulting in the inability of additive manufacturing to proceed normally. Observing the forming morphology, the effective width of a single wall is 5mm, the wetting angle between the upper and lower layers is greater than 90°, and the surface roughness of the side wall is large. It is worth noting that even if the heat input is small, the arc extinction position still collapses, and the height of the two ends of the wall is lower than the middle section. This is caused by the high thermal conductivity of the material and heat accumulation.

[0046] Figure 4 (b) is the deposition result of high heat input in constant heat input mode. Using high heat input can ensure smooth arc starting and avoid "wire sticking" phenomenon; however, high heat input will cause the remelting layer to be too thick and the molten pool to be too large during the deposition process, resulting in the collapse of the overall height of the wall, and the height of the additive material is difficult to achieve the expected height. Due to the lack of support for the molten pool and the deterioration of heat dissipation conditions at the arc extinguishing position, serious collapse and molten pool flow will occur, which will eventually make additive material impossible.

[0047] Depend on Figure 4 (a) Figure 4 (b) It can be seen that the additive process using a constant heat input mode cannot produce chromium-zirconium-copper structural parts with good morphology and high dimensional accuracy.

[0048] Figure 4 (c) is a wall manufactured by the heat input dynamic adjustment method proposed in the present invention in Example 1. During the additive process, the heat input changes with the heat accumulation state, realizing precise control of the molten pool. The formed morphology is observed. There is no obvious collapse of the whole wall. The upper surface of the deposited layer is flat. The effective width of the wall is 8mm. The upper and lower layers fit tightly. The surface roughness of the side wall of the wall is low. The chromium-zirconium-copper additive component manufactured by the method of the present invention can obtain good formed morphology and dimensional accuracy, and improve material utilization.

[0049] Example 2: The difference from Example 1 is that the welding wire in step (1) is changed to a pure copper welding wire with a diameter of 1.2 mm; the deposition wall size in step (2) is changed to a single-pass thin-walled component with a length of 80 mm and a height of 50 mm; the heat input adjustment variable in step (6) is changed to the wire feeding speed to regulate the heat input in the additive process.

[0050] This embodiment uses a heat input dynamic adjustment strategy to manufacture a pure copper thin-walled part such as Figure 5 As shown, the wall has no collapse, the formed morphology is good, the side wall is flat, and the forming accuracy is good.

[0051] The above description is only for expressing the embodiments of the method proposed by the present invention, and does not limit the present invention in any form. Any simple modification, equivalent changes and modifications made to the above embodiments based on the technical essence of the present invention are within the scope of the technical solution of the present invention.

Claims

1. A method for additively manufacturing copper and copper alloys by arc fuse with dynamic control of heat input within a layer, characterized in that: By monitoring the temperature online, the temperature of the arc starting position is monitored at the beginning of each deposition. When the temperature is within the set range, additive manufacturing begins. In the arc starting stage, large heat input is used to ensure arc starting to avoid "wire sticking failure" that causes interruption of additive manufacturing. After the molten pool is stably formed, the heat input is gradually reduced. In the middle stable section of deposition, medium heat input is used to maintain a stable molten pool size to ensure that the deposited layer has sufficient molten width and a suitable deposition angle. In the arc extinction stage of deposition, the arc heat input is quickly reduced to avoid heat accumulation to form an excessively large molten pool, which leads to melting collapse at the end of deposition. Layer by layer deposition is performed to prepare copper and copper alloy components with good morphology.

2. According to claim 1, a method for manufacturing copper and copper alloys by arc fuse additive with dynamic control of heat input within a layer, characterized in that: The following steps are involved: Step 1: Use a heating plate to preheat the substrate until the surface temperature of the substrate reaches above 130°C, then stop preheating; Step 2: Use an infrared pyrometer to monitor the temperature of the arc starting position online. When the temperature is within the range of 120°C-130°C, start additive manufacturing; when the temperature is lower than 120°C, use a hot air gun to heat the arc starting position; Step 3: Under the constant heat input mode, multiple groups of single-pass additive experiments are carried out, and the heat input power corresponding to the group with the best weld bead morphology is selected and set as the standard power; Step 4: Dynamically adjust the heat input during the deposition process. Select the heat input adjustment variable during the additive process. The adjustment variable includes the wire feeding speed, the deposition moving speed or the CMT / P balance coefficient. According to the corresponding relationship between the adjustment variable and the heat input power, change the adjustment variable during the deposition process to control the heat input. In the arc starting stage, use a high heat input of more than 110% of the standard power to start the arc, and gradually reduce the heat input after the molten pool is stably formed. When entering the intermediate stable stage, use medium heat input of 105% to 95% of the standard power, and control the heat input during the deposition process according to the set program to ensure that the deposited layer has sufficient molten width and appropriate cladding angle; in the arc extinction stage, quickly reduce the heat input to less than 80% of the standard power to avoid collapse caused by excessive molten pool, thus completing one layer of additive deposition; Step 5, repeating steps 2 and 4 in sequence, adding material layer by layer, and finally forming a deposited part; Step 6: Remove the deposited part, cut the additively formed part from the substrate using an electric spark discharge cutting machine, and observe and evaluate the formed morphology.

3. The method according to claim 2, characterized in that: The adjustment variables in step 4 include wire feeding speed, deposition moving speed or CMT / P balance coefficient, and a single variable or multiple variables are selected to coordinately realize dynamic regulation of heat input.

4. The method according to claim 2, characterized in that: The step 4 dynamically adjusts the heat input during the deposition process throughout each additive deposition process from arc starting to arc extinction.

5. The device used in the method for manufacturing copper and copper alloys by arc fuse additive manufacturing with dynamic control of heat input within a layer as claimed in any one of claims 1 to 4, characterized in that: The invention comprises an additive platform (9), a heating plate (8) is placed on the additive platform (9), the heating plate (8) is connected to a temperature controller (7), a substrate (1) is placed on the heating plate (8), a deposited formed part (2) is placed on the substrate (1), a welding gun (3) is arranged above the deposited formed part (2), the welding gun (3) is connected to a welding machine (10) and an argon gas bottle (11); an infrared pyrometer (4) is arranged next to the deposited formed part (2), the signal output of the infrared pyrometer (4) is connected to the signal input end of a computer (5), the signal output end of the computer (5) is connected to the signal input end of a control box (6), and the output end of the control box (6) is connected to the additive platform (9) and the control end of the welding machine (10).

Images