Interlayer rapid cooling electric arc additive manufacturing device and method

Abstract

The invention belongs to the technical field of electric arc additive manufacturing, and discloses an interlayer rapid cooling electric arc additive manufacturing device and method.The interlayer rapid cooling electric arc additive manufacturing device comprises electric arc additive equipment, a cooling cylinder, a base, a heat insulation layer, a heating device, a lifting device and a temperature control system; the cooling cylinder is located below the base and used for containing cooling liquid. The heat insulation layer is arranged at the bottom of the base, the heating device is used for heating the base and an additive workpiece, and the lifting device is connected with the base and used for adjusting the height of the base; a telescopic blocking layer is arranged between the bottom of the heat insulation layer and the bottom face of the cooling cylinder to prevent cooling liquid from entering the position below the heat insulation layer. Cooling liquid serves as a cooling medium, the height of a workpiece is adjusted through the lifting columns, the workpiece enters the cooling liquid to be cooled, welding and cooling are conducted in turn, interlayer rapid cooling is achieved, excessive heat generated in the material adding process is conducted out in time, the workpiece is prevented from being overheated, and the welding quality of the workpiece is improved. And therefore, high-quality and high-efficiency additive manufacturing is realized.

Description

Technical Field

[0001] The present invention relates to the technical field of arc additive manufacturing, and particularly to an apparatus and method for interlayer rapid cooling arc additive manufacturing. Background Art

[0002] Arc Additive Manufacturing (WAAM for short) is a typical process in additive manufacturing technology. By combining welding technology with computer technology, the three-dimensional model of the workpiece to be printed is imported into the arc additive software, sliced and an additive path is generated. The welding robot prints the workpiece according to the additive path. During the process, the welding wire is melted by the arc and then solidified into shape, and deposited layer by layer until the workpiece printing is completed. Arc additive manufacturing technology has the advantages of high material utilization rate and high forming efficiency. However, due to the layer-by-layer stacking characteristics of WAAM, serious heat accumulation, rough microstructure and insufficient mechanical properties often occur during the manufacturing process of components.

[0003] By optimizing welding parameters, shielding gas and wire composition, etc., the stability of the additive process and the mechanical properties of the workpiece are enhanced. However, the interlayer treatment process during the additive process is also crucial. A reasonable interlayer treatment process can significantly improve the microstructure and mechanical properties of WAAM components. However, the issues of time and process cost also need to be considered. By adopting interlayer rapid cooling, while ensuring the overall efficiency of component production, the interlayer heat accumulation is reduced. By controlling the interlayer temperature, the solidification rate and heat treatment history of the material can be adjusted, thereby affecting the microstructure, such as grain size, phase composition and grain boundary characteristics, etc., which is crucial for the mechanical properties of the additive workpiece.

[0004] Currently, the research on controlling the additive manufacturing process by adjusting the interlayer temperature is relatively lacking. In addition, due to the heat accumulation effect in additive manufacturing, it is difficult to accurately control the interlayer temperature in current research, which may lead to unpredictable risks in workpiece quality. Therefore, how to achieve interlayer rapid cooling during the arc additive manufacturing process has become a technical problem that needs to be urgently solved by those skilled in the art. Summary of the Invention

[0005] The purpose of the present invention is to provide an apparatus and method for interlayer rapid cooling arc additive manufacturing, using coolant as the cooling medium, flexibly switching the arc additive manufacturing process and the cooling state through a lifting column, cooling while welding, achieving interlayer rapid cooling, and timely discharging the excessive heat generated during the additive process, avoiding overheating of the formed part, thereby realizing high-quality and efficient additive manufacturing.

[0006] To achieve the above object, the present invention provides the following solutions:

[0007] An arc additive manufacturing device with rapid interlayer cooling, characterized in that it includes an arc additive manufacturing equipment, a cooling cylinder, a base, a heat insulation layer, a heating device, a lifting device, and a temperature control system;

[0008] The cooling cylinder has an upward opening and is located below the base, and is used to contain coolant; a liquid inlet valve and a liquid discharge valve are arranged on the cooling cylinder; the heat insulation layer is arranged at the bottom of the base, and the heating device is used to heat the base and the additive workpiece,

[0009] The lifting device is connected to the base and is used to adjust the relative height between the base and the cooling cylinder;

[0010] A telescopic partition layer is arranged between the bottom of the heat insulation layer and the bottom surface of the cooling cylinder to prevent the coolant from entering below the heat insulation layer;

[0011] The temperature control system includes a first temperature sensor arranged in the cooling cylinder, a second temperature sensor for detecting the temperature of the additive workpiece, and a controller; the controller is respectively connected to the arc additive manufacturing equipment, the lifting device, the liquid inlet valve, the liquid discharge valve, the first temperature sensor, the second temperature sensor, and the heating device, and is used to monitor the temperature of the coolant and the additive workpiece, as well as control the lifting device, the coolant circulation, and the heating power of the heating device.

[0012] Further, the lifting device is a plurality of telescopic lifting columns, and the lifting columns are located in the closed space surrounded by the partition layer, the heat insulation layer, and the bottom surface of the cooling cylinder.

[0013] Further, the second temperature sensor is a non-contact temperature sensor.

[0014] Further, there are four telescopic columns, which are evenly arranged in the circumferential direction.

[0015] Further, the heating device is a heating column arranged below the base and penetrating the heat insulation layer to abut against the base.

[0016] Further, the arc additive manufacturing equipment includes a welding torch, a welding wire, a wire feeding device, and a shielding gas nozzle, and the welding torch, the welding wire, the wire feeding device, and the shielding gas nozzle are all located directly above the base.

[0017] An arc additive manufacturing method based on the arc additive manufacturing device with rapid interlayer cooling, characterized in that it includes the following steps:

[0018] S1. Using the arc as the welding heat source, the wire feeding device sends the welding wire as the consumable electrode out of the welding torch. The welding torch is located above the substrate, and there is a shielding gas nozzle outside the welding torch. Fix the substrate of the additive workpiece on the base;

[0019] S2. Adjust the height of the base to 2 / 3 of the height of the cooling cylinder through the lifting device, and inject coolant into the cooling cylinder;

[0020] S3. Adjust the lifting device again to place the base 1 - 2 cm above the coolant. Select the arc starting and extinguishing positions on the substrate, set the shielding gas nozzle to start jetting gas 0.5 s before arc starting during welding, and preheat the substrate and / or the additive workpiece to the process - required temperature through the heating device;

[0021] S4. After completing the first weld bead, turn off the welding torch, continue supplying shielding gas for 3 - 5 s, then raise the welding torch by 2 - 3 cm, move it to an appropriate position, adjust the lifting device to make the surface of the substrate and / or the additive workpiece on the base 5 - 10 mm below the coolant for cooling;

[0022] S5. After cooling is completed, adjust the lifting device to make the surface of the substrate and / or the additive workpiece on the base 5 - 10 mm above the coolant, dry the additive workpiece, and repeat steps S3 and S4 until the manufacturing of the additive workpiece is completed.

[0023] Further, in steps S3 and S4, the surfacing layer contains multiple weld beads. After completing the previous weld bead, move the welding torch 1 - 2 cm for the next surfacing.

[0024] Further, the flow rate of the shielding gas ejected by the shielding gas nozzle is 15 - 25 L / min, and the shielding gas is a mixed shielding gas of one or two of pure argon and pure helium.

[0025] Further, the diameter of the welding wire is 0.8 mm - 2.4 mm, and the dry extension length of the welding wire is 10 - 15 times the diameter of the welding wire.

[0026] According to the specific embodiments provided by the present invention, the following technical effects are disclosed:

[0027] The arc additive manufacturing device and method with rapid interlayer cooling provided by the present invention uses coolant as the cooling medium, adjusts the height position of the additive workpiece through the telescopic column, and the heating column can preheat the substrate. During the arc additive manufacturing process, after each weld bead is completed, the workpiece is moved below the coolant to achieve rapid interlayer cooling, solving the problem of serious heat accumulation during the arc additive manufacturing process, effectively avoiding the problem of collapse of low - melting - point alloys during additive manufacturing, and at the same time solving the disadvantages of coarse and unevenly distributed grains caused by heat accumulation, making the welding stable during the additive manufacturing process, with good forming quality and increased process reliability; in addition, since the temperature of the substrate is at room temperature when arc additive manufacturing is carried out on the substrate, preheating the substrate can improve the welding quality of the first layer, thereby improving the efficiency of arc additive manufacturing workpieces. Description of the Drawings

[0028] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the following will briefly introduce the drawings required for use in the embodiments. Obviously, the drawings described below are only some embodiments of the present invention. For those of ordinary skill in the art, without creative efforts, other drawings can also be obtained based on these drawings.

[0029] Figure 1 It is a schematic structural diagram of the device for rapid interlayer cooling in arc additive manufacturing of the present invention.

[0030] Figure 2 It is a sectional view of the front view of the device for rapid interlayer cooling in arc additive manufacturing of the present invention.

[0031] Figure 3 It is a schematic diagram of the main structure of the device for rapid interlayer cooling in arc additive manufacturing of the present invention.

[0032] Figure 4 It is a schematic diagram of the welding process of the device for rapid interlayer cooling in arc additive manufacturing of the present invention.

[0033] Explanation of reference numerals:

[0034] 1. Welding torch; 2. Welding wire; 3. Additive workpiece; 4. Substrate; 5. Base; 6. Thermal insulation layer; 7. Partition layer; 8. Lifting column; 9. Heating column; 10. Cooling cylinder; 11. Drain valve. Detailed implementation manners

[0035] The following will clearly and completely describe the technical solutions in the embodiments of the present invention with reference to the drawings in the embodiments of the present invention. Obviously, the described embodiments are only some embodiments of the present invention, rather than all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative efforts belong to the scope of protection of the present invention.

[0036] In the description of the present invention, if there are terms such as "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", etc. indicating the orientation or position relationship, it is based on the actual orientation or position relationship shown. It is only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation. Therefore, the terms used to describe the orientation or position relationship in the present invention are only for illustrative purposes and cannot be understood as a limitation of the present invention. For those of ordinary skill in the art, the specific meanings of the above terms can be understood in combination with the embodiments and according to the specific circumstances.

[0037] Unless otherwise clearly defined and limited, in the present invention, if there are terms such as "arranged", "connected" and "coupled", they should be understood in a broad sense. For example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a direct connection, or an indirect connection through an intermediate medium, and it can be the communication inside two components. For those of ordinary skill in the art, the specific meanings of the above terms in the present invention can be understood according to specific situations.

[0038] The purpose of the present invention is to provide a device and method for rapid interlayer cooling in arc additive manufacturing. Since the cooling medium has strong heat conduction ability, excessive heat generated during the additive manufacturing process can be timely exported, avoiding overheating of the formed parts, thereby realizing high-quality and efficient additive manufacturing.

[0039] In order to make the above objects, features and advantages of the present invention more obvious and understandable, the present invention will be further described in detail below with reference to the accompanying drawings and specific embodiments.

[0040] As Figure 1 shown, the device for rapid interlayer cooling in arc additive manufacturing provided by the present invention includes an arc additive manufacturing device, a cooling cylinder 10, a base 5, a heat insulation layer 6, a heating device, a lifting device and a temperature control system. The arc additive manufacturing device includes a welding torch 1, a welding wire 2, a wire feeding device and a shielding gas nozzle, and the welding torch 1, the welding wire 2, the wire feeding device and the shielding gas nozzle are all located directly above the base 5.

[0041] The cooling cylinder 10 has an upward opening and is located below the base 5 for containing a coolant; an inlet valve and a drain valve 11 are provided on the cooling cylinder 10 to realize the injection and discharge of the coolant in the cooling cylinder 10. The heat insulation layer 6 is arranged at the bottom of the base 5, and the heating device is used to heat the base 5 and the additive workpiece 3. Specifically, the lifting device is four telescopic lifting columns 8, which are connected to the base 5 and are evenly arranged in the circumferential direction for adjusting the relative height between the base 5 and the cooling cylinder 4. The heating device is a heating column 9 arranged below the base 5 and penetrating through the heat insulation layer 6 to abut against the base 5.

[0042] A telescopic partition layer 7 is arranged between the bottom of the heat insulation layer 6 and the bottom surface of the cooling cylinder 10 to prevent the coolant from entering below the heat insulation layer 6; the lifting columns 8 and the heating columns 9 are located in the enclosed space formed by the partition layer 7, the heat insulation layer 6 and the bottom surface of the cooling cylinder 4.

[0043] The temperature control system includes a first temperature sensor disposed in the cooling cylinder 4, a second temperature sensor for detecting the temperature of the additive manufactured workpiece 3, and a controller. The second temperature sensor is a non-contact temperature sensor, such as an infrared temperature sensor. The controller is respectively connected to the arc additive manufacturing device, the lifting device, the liquid inlet valve, the liquid discharge valve 11, the first temperature sensor, the second temperature sensor and the heating device, and is used for monitoring the temperatures of the coolant and the additive manufactured workpiece 3, and controlling the lifting device, the coolant circulation and the heating power of the heating device.

[0044] During the working process, a plurality of layers of additive manufactured workpieces 3 are prepared on the base 5, and the arc additive manufacturing device prints out the additive manufactured workpieces 3 layer by layer in a stacked manner. The welding torch 1 can be a GMAW welding torch or a CMT welding torch.

[0045] The present invention applies the interlayer rapid cooling technology to the additive manufacturing process, and the additive manufacturing technology based on surfacing has different process requirements and characteristics from those of the ordinary workpiece welding technology. Welding mainly realizes the connection of different workpieces or surface treatment; while additive manufacturing needs to complete a product with certain performance, shape and size requirements through the superposition of multiple layers of surfacing metals, that is, a shaped part product composed of surfacing layer metals; the requirements for the shape and size after the superposition of the surfacing layers are relatively harsh, and there are many weld layers and welding paths during additive manufacturing, the thermal process is more complex, and the material performance and structure are more difficult to control. Therefore, the welding heat accumulation is controlled during the surfacing process of additive manufacturing.

[0046] A method for interlayer rapid cooling arc additive manufacturing provided by the present invention is applied to the above-mentioned interlayer rapid cooling arc additive manufacturing device, and includes the following steps:

[0047] S1, Using the arc as the welding heat source, the welding wire as the consumable electrode is sent out by the welding torch. The welding torch is located above the substrate. A shielding gas nozzle is arranged outside the welding torch. The substrate used for additive manufacturing is fixed on the base and restricted by a fixture to limit its degrees of freedom;

[0048] S2, Adjust the lifting column 8 until the height of the base 5 is at 2 / 3 of the height of the cooling cylinder, and inject coolant into the cooling cylinder 10; in the specific additive manufacturing process, different components of coolant can be used as the cooling medium to control the cooling rate.

[0049] S3, Adjust the lifting column 8 again until the base 5 is 1-2 cm above the coolant. Select the starting and ending arc positions on the substrate, and set the shielding gas nozzle to start jetting 0.5 s before the welding arc is started. Heat the substrate to the process required temperature through the base 5;

[0050] S4. After completing the first weld bead, turn off the welding torch. The shielding gas continues to be supplied for 3 - 5 s, then raise the welding torch by 2 - 3 cm, move it to an appropriate position, and adjust the lifting column 8 so that the upper surface of the base 5 or the additive workpiece 3 is 5 - 10 mm below the coolant.

[0051] S5. After cooling is completed, adjust the lifting device so that the surface of the substrate and / or the additive workpiece 3 on the base 5 is 5 - 10 mm above the coolant, dry the additive workpiece 3, and repeat steps S3 and S4 until the manufacturing of the additive workpiece is completed.

[0052] S6. On the basis of the first weld bead, perform the operations as described in steps S3 - S4 to complete the second weld bead.

[0053] S7. On the basis of the second weld bead, perform the operations as described in steps S3 - S4 until the manufacturing of the additive workpiece is completed.

[0054] S8. After the additive workpiece cools to room temperature, open the drain valve at the bottom of the cooling cylinder. After recovering the coolant, adjust the height of the telescopic column so that the base is at 2 / 3 of the height of the cooling cylinder, remove the fixture, and take out the additive workpiece.

[0055] Specifically, in steps S3 and S4, the surfacing layer contains multiple weld beads. After completing the previous weld bead, the welding torch is moved 1 - 2 cm for the next surfacing.

[0056] The flow rate of the shielding gas ejected from the shielding gas nozzle is 15 - 25 L / min. The shielding gas is pure argon, pure helium, or a mixed shielding gas of different types.

[0057] The diameter of the welding wire is 0.8 mm - 2.4 mm. The dry elongation length of the welding wire is 10 - 15 times the diameter of the welding wire.

[0058] In this article, specific examples are used to elaborate on the principle and implementation mode of the present invention. The description of the above embodiments is only used to help understand the method of the present invention and its core idea; at the same time, for those of ordinary skill in the art, according to the idea of the present invention, there will be changes in the specific implementation mode and application scope. In summary, the content of this specification should not be construed as a limitation of the present invention.

Claims

1. An arc additive manufacturing device with rapid interlayer cooling, characterized in that: It comprises an arc material adding device, a cooling cylinder (10), a base (5), a heat insulating layer (6), a heating device, a lifting device and a temperature control system; The cooling cylinder (10) opens upward and is located below the base (5), and is used to contain cooling liquid; a liquid inlet valve and a liquid outlet valve (11) are provided on the cooling cylinder (10); a heat insulating layer (6) is provided at the bottom of the base (5), and a heating device is used to heat the base (5) and the additive workpiece (3); The lifting device is connected to the base (5) and is used to adjust the relative height between the base (5) and the cooling cylinder (10); A retractable barrier layer (7) is provided between the bottom of the heat insulating layer (6) and the bottom surface of the cooling cylinder (10) to prevent the coolant from entering below the heat insulating layer (6); The temperature control system comprises a first temperature sensor arranged in a cooling cylinder (10), a second temperature sensor for detecting the temperature of an additive workpiece (3), and a controller; the controller is respectively connected to the arc additive device, the lifting device, the liquid inlet valve and the liquid outlet valve (11), the first temperature sensor, the second temperature sensor and the heating device, and is used to monitor the temperature of the coolant and the additive workpiece (3), and to control the lifting column, the coolant circulation and the heating power of the heating device.

2. The arc additive manufacturing device with rapid interlayer cooling according to claim 1, characterized in that: The lifting device is a plurality of retractable lifting columns (8), and the lifting columns (8) are located in a closed space surrounded by the barrier layer (7), the heat insulation layer (6) and the bottom surface of the cooling cylinder (10).

3. The arc additive manufacturing device with rapid interlayer cooling according to claim 1, characterized in that: The second temperature sensor is a non-contact temperature sensor.

4. The arc additive manufacturing device with rapid interlayer cooling according to claim 1, characterized in that: There are four lifting columns (8), which are evenly arranged in the circumferential direction.

5. The arc additive manufacturing device with rapid interlayer cooling according to claim 1, characterized in that: The heating device is a heating column (9) which is arranged below the base (5) and penetrates the heat insulating layer (6) to abut against the base (5).

6. The device for interlayer rapid cooling arc additive manufacturing according to claim 1, characterized in that: The arc material adding equipment comprises a welding gun (1), a welding wire (2), a wire feeding device, and a shielding gas nozzle, wherein the welding gun (1), the welding wire (2), the wire feeding device, and the shielding gas nozzle are all located directly above a base (5).

7. An arc additive manufacturing method based on the arc additive manufacturing device with interlayer rapid cooling according to any one of claims 1 to 6, characterized in that: The following steps are involved: S1. An electric arc is used as a welding heat source, and a wire feeding device feeds a welding wire (2) as a melting electrode from a welding gun (1). The welding wire (2) of the welding gun is located above a substrate (4). A protective gas nozzle is provided outside the welding gun (1), and the substrate (4) of the workpiece is fixed on a base (5); S2. The height of the base is adjusted by the lifting device to 2 / 3 of the height of the cooling cylinder (10), and the coolant is injected into the cooling cylinder (10); S3. Adjust the lifting device again so that the base (5) is located 1 to 2 cm above the coolant, select the arc starting and extinguishing position on the substrate (5), set the shielding gas nozzle to start jetting 0.5 seconds before the welding arc starts, and preheat the substrate and / or the additive workpiece (3) to the process required temperature through the heating device; S4. After the first weld pass is completed, the welding gun is turned off, the shielding gas is continuously supplied for 3 to 5 seconds, and then the welding gun is raised by 2 to 3 cm, moved to an appropriate position, and the lifting device is adjusted so that the substrate and / or the surface of the additive workpiece (3) on the base (5) is 5 to 10 mm below the coolant for cooling; S5. After cooling is completed, the lifting device is adjusted so that the surface of the substrate and / or the additive workpiece (3) on the base (5) is 5 to 10 mm above the coolant, the additive workpiece (3) is dried, and steps S3 and S4 are repeated until the manufacturing of the additive workpiece is completed.

8. The method for interlayer rapid cooling arc additive manufacturing according to claim 7, characterized in that: In the steps S3 and S4, the cladding layer includes multiple welds. After the previous weld is completed, the welding gun is moved 1 to 2 cm to perform the next cladding.

9. The method for interlayer rapid cooling arc additive manufacturing according to claim 7, characterized in that: The flow rate of the protective gas sprayed from the protective gas nozzle is 15-25 L / min, and the protective gas is pure argon, pure helium, or a mixed protective gas of the two.

10. The method for interlayer rapid cooling arc additive manufacturing according to claim 7, characterized in that: The diameter of the welding wire is 0.8 mm to 2.4 mm, and the dry extension length of the welding wire is 10 to 15 times the diameter of the welding wire.

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