Extended multi-mode cooling system for additive manufacturing and thermal stress suppression method

Abstract

The invention discloses an extended multi-mode cooling system for additive manufacturing and a thermal stress suppression method, the cooling system mainly comprises a bottom partition cooling device and an interlayer cooling device, a partition fractal water-cooling cooling platform is designed according to a bottom partition cooling basic mode, redundant heat in the bottom layer additive manufacturing process can be balanced according to the position of a substrate, and the cooling efficiency is improved. The substrate is fixedly installed on the heat-conducting runner plate, the heat-conducting runner plate is hollow and used for being filled with a cooling medium, the inside and the outside of the heat-conducting runner plate are connected through a pipeline, and the outside is connected with a pressure pump to enable the internal cooling medium to complete flowing circulation; aiming at an interlayer cooling dynamic mode, a splicable thermoelectric refrigerating unit is designed based on the Peltier effect, a welding gun is subjected to material adding in the middle, real-time cooling is achieved, and a splicable dynamic module can be autonomously adjusted and installed aiming at complex machining paths such as curves, arcs or corners. And self-adaption of the cooling strength during high-layer material adding is achieved by adjusting a regulation and control module for layout temperature control of the device.

Description

Technical Field

[0001] The present invention belongs to the field of additive manufacturing welding quality control, and particularly relates to an extended multi-modal additive manufacturing cooling system and a thermal stress suppression method. Background Art

[0002] Additive manufacturing (AM) is an advanced forming technology based on the principle of discrete accumulation. Driven by three-dimensional model data, it realizes the layer-by-layer cumulative manufacturing of materials, breaking through the dependence on tools in traditional subtractive manufacturing. This technology has advantages such as low cost, short cycle, and multi-material composite processing. Especially in the manufacturing of small-batch products in high-value-added industries such as automobiles, ships, and aerospace, it shows significant application prospects. With the increase in the geometric complexity and material cost of components, the technical advantages of additive manufacturing in forming efficiency and resource utilization are exponentially amplified. However, there are still technical bottlenecks in the thermal management and cooling system during the additive manufacturing process, which limit the forming quality of complex-shaped components. The existing integrated cooling devices for welding robots generally have inherent defects such as a single structural mode and limited heat exchange area, and it is difficult to meet the requirements of gradient heat dissipation for complex-shaped components.

[0003] Currently, in the cooling methods during the additive manufacturing process, various shielding gas conduits and nozzle mechanisms that move with the welding torch are commonly used, such as liquid nitrogen cooling. The characteristic of this type of solution is that it can directly spray liquid nitrogen on the high-temperature component that has just been deposited from the outside. Secondly, the overall cooling is achieved by building a forming chamber environment. This solution mainly cools down by reducing the overall temperature of the forming chamber where the component is located. There are also forced air cooling, semi-immersion cooling, water-cooled backing plate cooling, etc.

[0004] Although using liquid nitrogen in the above cooling methods can achieve rapid cooling, it is easy to cause the problem of uneven surface temperature of the component, and water condensate beads adhere to the surface of the conduit and nozzle, which are easy to drip onto the surface of the high-temperature deposited metal, causing oxidation and porosity defects. Secondly, it is also difficult to finely control the cooling flow rate from liquid nitrogen to the surface of the object. If the flow rate is too large, it will significantly reduce the arc heat, resulting in lack of fusion defects. If the flow rate is too low, it is difficult to achieve an effective forced cooling effect. Building a forming chamber environment is easily restricted when manufacturing large-sized components or special-shaped components, and it mainly cools the entire forming chamber, not the local high-temperature area, so the cooling economy and efficiency are low. Forced air cooling may cause rapid surface solidification due to rapid cooling, unable to effectively prevent the retention of gas in the molten pool, thus increasing the porosity.

[0005] During the process of process implementation, the existing water-cooled backing plates can only form a uniform temperature field, and have weak temperature control ability for high-layer continuous welding. As the number of additive layers increases, the heat dissipation path of the component is blocked, resulting in an intensified heat accumulation effect. On the one hand, the liquid residence time of the molten pool is prolonged, and the fluidity of the molten metal is abnormal, leading to the instability of the molten pool and a significant decrease in the surface forming accuracy. On the other hand, the thermodynamic conditions during the solidification process deteriorate, causing the coarsening of the microstructure and the formation of columnar crystal structures that penetrate multiple layers of deposition, thereby resulting in a decrease in the mechanical properties such as the fatigue resistance of the component. More seriously, continuous heat accumulation will trigger a non-uniform thermal stress field, leading to irreversible deformation of the component and even fatal defects such as macroscopic cracks. Summary of the Invention

[0006] The influence of the present invention on the layer height and path during the cooling additive manufacturing process can be achieved through a simple device, which can cool complex manufacturing links such as high-layer stacking and corner surfaces, avoid overheating and collapse during the additive process, and achieve high-efficiency and high-quality additive manufacturing with rapid refrigeration and no pollution to the arc.

[0007] The purpose of the present invention is to make up for the unsatisfactory cooling effect of semi-immersion liquid cooling and water-cooled backing plate cooling for high-layer stacking. A cooling system and a thermal stress suppression method for extended multi-modal additive manufacturing are proposed. A substrate is fixedly installed on the bottom platform, and interlayer cooling devices are placed on both sides of the additive path, and the interlayer cooling devices are offset and spliced according to the path shape and the expected additive height. This method can address the additive quality problems caused by the difficult cooling of complex paths such as curved surfaces and corners and the low cooling effect after high-layer stacking, achieve the cooling effect during the manufacturing process of complex paths and when the layer stack is relatively high, and improve the additive qualification rate and manufacturing efficiency.

[0008] Based on a cooling system and a thermal stress suppression method for extended multi-modal additive manufacturing, the principle of the present invention is that during the additive process, the cooling channels arranged in cooperation with the heat conduction flow channel plate in the base platform at the bottom of the substrate take away the excess heat. When continuously adding materials in the vertical direction, interlayer cooling devices are used, and the thermoelectric coolers placed on both sides of the path spliced according to the path take away the heat generated during the stacking process. The splicing and placement positions of the devices are adjusted according to the required shape and height to achieve a rapid and arc-pollution-free refrigeration effect between layers.

[0009] To achieve the above object, the present invention adopts the following technical solutions: An extended multi-modal additive manufacturing cooling system, including a partition cooling device, the partition cooling device is a basic mode built by a base platform and a heat conduction runner plate, the heat conduction runner plate is arranged on the base platform, and there is a connected cooling runner inside the heat conduction runner plate. Nodes are formed at the intersections inside the cooling runner, and adjustable and controllable solenoid valves are provided at the node positions. A pressure pump and a transition water tank are also provided on the base platform. One end of the pressure pump is provided with a connecting conduction pipe connecting to the transition water tank, and the other end is provided with a cooling pipeline connecting to the cooling runner. The other end of the cooling runner accesses the return liquid of the transition water tank. The transition water tank forms a cooling water cycle with the cooling runner inside the heat conduction runner plate through the pressure pump, the cooling pipeline, and the conduction pipe; an interlayer cooling device, the interlayer cooling device is an assembled dynamic mode, including a cuboid vertical and spliceable square structure with an embedded thermoelectric cooler in the middle. Trapezoidal groove splicing interfaces are provided on the adjacent sides of the square structure, and corresponding trapezoidal convex splicing interfaces are provided on the opposite sides of the adjacent sides of the square structure. The adjacent sides of the interlayer cooling device are spliced and combined to form interlayer cooling along the manufacturing path.

[0010] As a further setting of the above solution, the cooling runners arranged inside the heat conduction runner plate are connected in a crosswise and longitudinal intersection. Nodes are formed at the intersections of the vertical and horizontal directions. A controllable solenoid valve for regulating the flow direction of the cooling water in the runner is arranged at the node position. Mounting holes are also provided on the heat conduction runner plate for fixing and placing the manufacturing substrate. The heat during the manufacturing process is conducted from the substrate to the heat conduction runner plate, and then the heat is dispersed by the internal cooling runner of the heat conduction runner plate to cool the heat conduction runner plate.

[0011] As a further setting of the above solution, the controllable solenoid valve arranged on the heat conduction runner plate has four valve ports to control the flow direction of the water inside the cooling runner. The controllable solenoid valve is used to adjust the opening according to the fixed position of the substrate, so that a complete closed cooling runner is formed inside the heat conduction runner plate below the substrate. The valve ports of the controllable solenoid valves around the substrate facing away from the substrate direction are all closed, and the valve ports facing the substrate direction are selectively opened according to the designed cooling runner path, so as to realize the partitioned and fractal adjustable basic mode cooling function.

[0012] As a further setting of the above solution, an installation frame is also arranged inside the base platform. The pressure pump is fixed on the installation frame. The cooling pipeline connected to one side of the pressure pump and the conduction pipe on the other side are connected to the transition water tank. By driving the pressure pump, the cooling water is pumped out from the transition water tank and brought into the heat conduction runner plate through the cooling pipeline, and then brought back to the transition water tank through the cooling pipeline at the other side of the heat conduction runner plate to realize circulating cooling.

[0013] As a further setting of the above solution, the thermoelectric cooler adopts the Peltier effect. By setting an external DC power supply, a cooling end face and a heating end face are formed. The outside of the cooling end face is wrapped with high thermal conductivity silica gel, and a heat sink is assembled outside the heating end face.

[0014] As a further setting of the above solution, the interlayer cooling device further includes a thermoelectric cooling component housing covering the outside of the thermoelectric cooler. The high thermal conductivity silica gel and the heat sink are arranged on two side faces of the thermoelectric cooling component housing. The high thermal conductivity silica gel is in direct contact with the cooling end face, and the heat sink is spaced from the heating end face and fixed on the thermoelectric cooling component housing.

[0015] As a further setting of the above solution, the thermoelectric cooling component housing is provided with opposite side grooves, side protrusions, top protrusions and bottom grooves. It is installed in a vertical position. The thermoelectric cooler is symmetrically placed on both sides of the manufacturing path on the manufacturing substrate through the side grooves, side protrusions, top protrusions and bottom grooves. A manufacturing path is reserved in the middle of the cooling end face for the arc welding torch to travel. The manufacturing path is used to adjust the placement position of the thermoelectric cooler for local precise cooling of complex paths.

[0016] As a further setting of the above solution, both the top protrusion and the side protrusion are provided with rotating shafts. When the interlayer cooling device is assembled, the rotating shafts are used to adjust the swing angle between two adjacent thermoelectric coolers along the horizontal and vertical directions to fit the manufacturing path.

[0017] Through the above structural settings, the scalable multi-modal arc additive manufacturing cooling system of the present invention includes a base platform, a welding torch, a pressure pump, a conduction pipe, a transition water tank, an interlayer cooling device, a thermoelectric cooler, and an external DC power supply. A substrate is also provided and fixed on a heat conduction flow channel plate at the top of the base platform. Multiple cooling flow channels are arranged inside the heat conduction flow channel plate. A controllable solenoid valve is provided at the intersection node of the cooling flow channels to ensure that the flow channels inside the heat conduction flow channel plate build a basic mode to achieve the function of zone cooling. The welding torch moves empty to simulate the additive path, and the interlayer cooling device is placed according to the path. The placement position is along both sides of the manufacturing path, and the cooling end faces of the thermoelectric coolers on both sides are placed towards the manufacturing path direction to ensure that the thermoelectric cooler will not interfere with the progress of the welding torch during the additive process, and to ensure that the dynamic mode can be formed at startup to effectively cool the product interlayer; after the substrate is preheated during the additive process, when starting the manufacturing, the zone cooling device inside the base platform is started to circulate and cool the bottom area of the substrate. When continuing the manufacturing, the interlayer cooling device is started, and the thermoelectric cooler is powered by the external DC power supply to cool the product. If the additive process reaches the expected set height, by constructing a control mode, the interlayer cooling device is spliced upward based on the modal weight distribution of the path curvature, and the angle of the interlayer cooling device is adjusted according to the product shape to continuously cool the product and control the product temperature within the manufacturing range; this composite device cools the arc additive manufacturing.

[0018] The present invention also provides a stress suppression method for a cooling system for extended multi-modal additive manufacturing, including the following steps:

[0019] a Fix the substrate on the heat conduction flow channel plate in advance and plan to simulate the additive path;

[0020] b Additive preparation work. First, prepare the manufacturing consumables and adjust the welding torch nozzle; connect the ion gas and shielding gas required by the welding torch according to the conventional method; the welding torch moves along the path empty and records the path;

[0021] c Adjust the controllable solenoid valve according to the fixed position of the substrate so that a closed loop is formed between the cooling flow channels in the bottom area of the substrate and the transition water tank. Start the pressure pump to bring the cooling water in the transition water tank into the heat conduction flow channel plate through the cooling pipeline to cool the bottom layer of the additive from below. Multiple closed loops are set according to the stacking height of the additive, and the density of the closed loops is proportional to the number of stacking layers to keep the temperature of the additive workpiece evenly balanced;

[0022] After the additive height exceeds the cooling range of the bottom layer, outside the lower layer of the material that has been additively manufactured, an interlayer cooling device is placed outside the lower workpiece. During installation, it is set by rotating the rotating shaft to control the swing fine-tuning between two adjacent thermoelectric coolers. The cooling end face of the thermoelectric cooler is placed along the manufacturing path and in contact with the surface of the semi-finished workpiece that has completed additive manufacturing, so that the highly thermally conductive silicone on the cooling end face directly contacts the additively manufactured workpiece for nearby heat conduction and cooling. According to the simulated path, the thermoelectric coolers are spliced in multiple segments according to the additive length and height to be carried out next to ensure the manufacturing effect;

[0023] e Manufacturing process: First, preheat the substrate. According to the pre-set manufacturing path, control the welding torch to reach the specified position to start additive manufacturing. At the same time, start the pressure pump, and the partition cooling device starts to work to cool the bottom layer product of the substrate for additive manufacturing;

[0024] f When the additive height exceeds the height of a single interlayer cooling device, assemble and start the interlayer cooling device in the manner of step d, and cool it through the thermoelectric cooler attached to the lower workpiece. When the additive height exceeds the single-layer cooling range of the single interlayer cooling device, continue to splice upward through the top convex groove and the bottom concave groove to increase the cooling range and maintain cooling;

[0025] g In step f, according to the partition cooling device 1 and after assembling the interlayer cooling devices above the second layer, those that do not play a role in cooling and temperature reduction can be turned off.

[0026] An extended multi-modal additive manufacturing cooling system and thermal stress suppression method of the present invention are used for cooling at corners and curved paths during the additive manufacturing process and sustainable cooling as the number of layers increases during the additive manufacturing process. The whole method includes a base platform, a transition water tank, a partition cooling device, an interlayer cooling device, an external DC power supply, etc. According to the basic mode: the partition cooling device cools the substrate, solves the bottom layer additive product, and provides a temperature buffer for the upper layer cooling. Then, through the dynamic mode: the splicable interlayer cooling device according to path following solves the local precise cooling of complex paths, forms a thermal field gradient in the additive height direction with water cooling, and realizes high-quality cooling of arc additive manufacturing. This method can optimize problems such as complex paths and low cooling efficiency at high layers, realize efficient and pollution-free cooling of arc additive manufacturing, and improve the additive quality.

[0027] Compared with the prior art, the advantages of the method of the present invention are as follows:

[0028] 1. Compared with liquid nitrogen cooling, the present invention can achieve no pollution on the surface of the manufactured product, no pores and oxidation phenomena; through the recycling device, the material consumption is significantly reduced, and the cheap and good-cooling-effect cooling water is used to achieve the cooling purpose.

[0029] 2. Compared with water-cooled backing plate refrigeration, and compared with uniform refrigeration in a local area, the present invention can achieve uninterrupted refrigeration during a continuous manufacturing process and after the layer height increases; through a controllable solenoid valve controlled according to the temperature requirements of the additive layer materials, multiple closed loops with different heat dissipation capabilities are formed, so as to achieve uniform temperature control of the additive materials above, form a splicing composite cooling function, overcome the cooling equality caused by refrigeration for a single-direction path, resulting in non-uniformity due to the self-heating temperature of the materials, and solve problems such as the inability of the backing plate refrigeration to effectively refrigerate high-layer products through a dynamic cooling structure.

[0030] 3. In the expandable multi-modal arc additive manufacturing cooling system and thermal stress suppression method of the present invention, the substrate is fixed to the heat conduction flow channel plate on the base platform. The controllable solenoid valve inside the heat conduction flow channel plate adjusts the partition cooling flow channel for the fixed position of the substrate, completes the construction of the basic mode and solves the bottom-layer basic heat dissipation; determines the placement position of the interlayer cooler through the empty running path of the welding torch, starts the partition cooling device of the base platform for cooling during the additive process, turns on the external power supply to supply power to the thermoelectric cooler to achieve interlayer cooling, completes the construction of the dynamic mode and performs local precise cooling for complex paths; finally, realizes the construction of the regulation mode through the temperature control reconstruction of the device layout to effectively solve the cooling intensity adaptability during high-layer additive manufacturing, and suppresses thermal stress by changing the heat conduction path through spatial reconstruction. Brief Description of the Drawings

[0031] Figure 1 It is a schematic structural diagram of the cooling system of the present invention.

[0032] Figure 2 It is a schematic structural diagram of the partition cooling device of the cooling system of the present invention.

[0033] Figure 3 It is a schematic diagram of the flow channel line of the internal heat conduction flow channel plate in the cooling system example of the present invention.

[0034] Figure 4 It is a schematic structural diagram of the heat generation end face of the thermoelectric cooler of the present invention.

[0035] Figure 5 It is a schematic structural diagram of the refrigeration end face of the thermoelectric cooler of the present invention.

[0036] Figure 6 It is a schematic structural diagram of the shaft connection of the thermoelectric cooler of the present invention.

[0037] Figure 7 It is a schematic diagram of the installation state of the interlayer cooling device of the present invention

[0038] Figure 8 It is a schematic diagram of the state where the interlayer cooling device fits the product of the present invention.

[0039] Figure 9This is a schematic diagram of the dynamic adjustment of the interlayer cooling device of the present invention.

[0040] Description of the reference numerals: 1. Partition cooling device; 101. Base platform; 102. Heat conduction flow channel plate; 103. Pressure pump; 104. Cooling pipeline; 105. Platform water outlet; 106. Platform water inlet; 107. Conducting pipe; 108. Mounting frame; 109. Transition water tank; 110. Cooling flow channel; 112. Water changing port; 113. Controllable solenoid valve; 2. Interlayer cooling device; 201. Thermoelectric cooler; 202. Top convex groove; 203. Side groove; 204. Side convex groove; 205. Bottom groove; 206. Rotating shaft; 207. Refrigerating end face; 208. Heating end face; 209. External DC power supply; 210. Heat dissipation plate; 211. High thermal conductivity silicone; 212. Thermoelectric refrigeration module housing; 301. Welding torch; 302. Substrate; 303. Additive component; 304. Plate fixing device. Detailed implementation manners

[0041] The following combines the drawings and embodiments to further describe in detail the specific implementation manners of the present invention. The following embodiments are used to illustrate the present invention, but are not used to limit the scope of the present invention.

[0042] Referring to Figures 1-9 As shown, an extended multi-modal additive manufacturing cooling system of the present invention includes a partition cooling device 1. The partition cooling device 1 is a basic mode built by a base platform 101 and a heat conduction flow channel plate 102. The heat conduction flow channel plate 102 is arranged on the base platform 101. A communicating cooling flow channel 110 is provided inside the heat conduction flow channel plate 102. Nodes are formed at the intersection inside the cooling flow channel 110, and a controllable solenoid valve 113 is provided at the node position. A pressure pump 103 and a transition water tank 109 are further provided on the base platform 101. One end of the pressure pump 103 is provided with a connecting conducting pipe 107 to connect to the transition water tank 109, and the other end is provided with a cooling pipeline 104 to connect to the cooling flow channel 110. The other end of the cooling flow channel 110 accesses the transition water tank 109 for liquid return. The transition water tank 109 forms a cooling water cycle with the cooling flow channel 110 inside the heat conduction flow channel plate 102 by relying on the pressure pump 103, the cooling pipeline 104, and the conducting pipe 107;

[0043] An interlayer cooling device 2. The interlayer cooling device 2 is an assembled dynamic mode, including a cuboid vertical and spliceable square structure with an embedded thermoelectric cooler 201 in the middle. Trapezoidal groove splicing interfaces are provided on the adjacent sides of the square structure, and corresponding trapezoidal convex splicing interfaces are provided on the opposite sides of the adjacent sides of the square structure. The adjacent sides of the interlayer cooling device 2 are spliced and combined to form interlayer cooling along the manufacturing path.

[0044] As a further setting of the above solution, the cooling channels 110 provided in the heat-conducting runner plate 102 are connected in a crosswise and longitudinal intersection, where nodes are formed at the intersection. A controllable solenoid valve 113 for regulating the flow direction of the cooling water in the channels is arranged at the node position. The heat-conducting runner plate 102 is also provided with mounting holes for fixedly placing the manufacturing substrate 302. The heat generated during the manufacturing process is conducted from the substrate 302 to the heat-conducting runner plate 102, and then the heat is dissipated through the internal cooling channels 110 of the heat-conducting runner plate 102 to cool the heat-conducting runner plate 102. The controllable solenoid valve 113 provided on the heat-conducting runner plate 102 is provided with four valve ports to control the flow direction of the water inside the cooling channels 110. The controllable solenoid valve 113 is used to adjust the opening according to the fixed position of the substrate 302, so that a complete closed cooling channel 110 is formed inside the heat-conducting runner plate 102 below the substrate 302. The valve ports of the controllable solenoid valve 113 facing away from the substrate 302 around the substrate 302 are all closed, and the valve ports facing the substrate 302 are selectively opened according to the designed path of the cooling channels 110, so as to realize the basic mode cooling function of zoning and fractal adjustable cooling.

[0045] As a further setting of the above solution, an installation frame 108 is also arranged inside the base platform 101. The pressure pump 103 is fixed on the installation frame 108. The cooling pipeline 104 connected to one side of the pressure pump 103 and the conduction pipe 107 on the other side are connected to the transition water tank 109. By driving the pressure pump 103, the cooling water is pumped out from the transition water tank 109, brought into the heat-conducting runner plate 102 through the cooling pipeline 104, and then brought back to the transition water tank 109 through the cooling pipeline 104 at the other side of the heat-conducting runner plate 102, so as to realize circulating cooling.

[0046] As a further setting of the above solution, the thermoelectric cooler 201 adopts the Peltier effect. By setting an external DC power supply 209, a refrigerating end face 207 and a heating end face 208 are formed. The outside of the refrigerating end face 207 is wrapped with high thermal conductivity silica gel 211, and a heat sink 210 is assembled outside the heating end face 208. The interlayer cooling device 2 further includes a thermoelectric cooling component housing 212 covering the outside of the thermoelectric cooler 201. The high thermal conductivity silica gel 211 and the heat sink 210 are arranged on two side faces of the thermoelectric cooling component housing 212. The high thermal conductivity silica gel 211 is in direct contact with the refrigerating end face 207, and the heat sink 210 is spaced from the heating end face 208 and fixed on the thermoelectric cooling component housing 212. The thermoelectric cooling component housing 212 is provided with opposite side grooves 203 and side protrusions 204, top protrusions 202 and bottom grooves 205. It is installed in a vertical placement. The thermoelectric cooler 201 is symmetrically placed on the manufacturing substrate 302 along both sides of the manufacturing path through the side grooves 203 and side protrusions 204, top protrusions 202 and bottom grooves 205. A manufacturing path is reserved in the middle of the refrigerating end face 207 for the arc welding torch 301 to travel. The manufacturing path is used to adjust the placement position of the thermoelectric cooler 201 for local precise cooling of complex paths.

[0047] The present invention also provides a stress suppression method for a cooling system of an extended multi-modal additive manufacturing, including the following steps:

[0048] a. Fix the substrate 302 on the heat conduction runner plate 102 in advance, plan and simulate the additive path, analyze the path according to the additive shape, and use software to form a cooling requirement based on the number of additive layers, path length, etc.

[0049] b. Additive preparation work. First, prepare the manufacturing consumables and place them into the welding torch 301 assembly, and then adjust the nozzle of the welding torch 301. Subsequently, connect the required ion gas and shielding gas of the welding torch 301 according to the conventional method, and form and record the manufacturing path and the idle running path of the welding torch 301 according to step a.

[0050] c. Adjust the controllable solenoid valve 113 according to the fixed position of the substrate 302, so that a closed loop is formed between the inner cooling runner 110 and the transition water tank 109 in the bottom area of the substrate 302. Start the pressure pump 103 to bring the cooling water in the transition water tank 109 into the heat conduction runner plate 102 through the cooling pipeline 104 to cool the bottom layer of the additive from below. It should be noted that the closed loop formed by the controllable solenoid valve 113 includes multiple closed loops set according to the stacking height of the additive, and the density between the multiple closed loops is proportional to the stacking layers, which is used to keep the temperature of the additive workpiece evenly balanced.

[0051] After the additive height exceeds the cooling range of the bottom layer, outside the lower layer of material that has been additively manufactured, place the interlayer cooling device 2 outside the lower workpiece. When setting it, set it based on the rotation of the rotating shaft 206, control the swing fine-tuning between adjacent two thermoelectric coolers 201, and place the cooling end face 207 of the thermoelectric cooler 201 along the manufacturing path and close to the surface of the semi-finished workpiece that has completed additive manufacturing, so that the high thermal conductivity silicone rubber 211 on the cooling end face 207 directly contacts the additively manufactured workpiece for precise heat conduction and cooling nearby. And according to the simulated path, splice the thermoelectric cooler 201 in multiple sections for the additive length and height to be carried out next to ensure the manufacturing effect;

[0052] e Manufacturing process: First, preheat the substrate 302. According to the pre-set manufacturing path, control the welding torch 301 to reach the specified position to start additive manufacturing; Subsequently, while the welding torch 301 is operating, start the pressure pump 103 so that the partition cooling device 1 starts to work to cool the bottom layer product of the additive manufacturing on the substrate 302;

[0053] f When the additive height exceeds the height of a single interlayer cooling device 2, assemble and start the interlayer cooling device 2 in the manner of step d, and cool it through the thermoelectric cooler 201 attached to the lower workpiece. When the additive height exceeds the single-layer cooling range of the single interlayer cooling device 2, continue to splice upward through the top convex groove 202 and the bottom groove 205 provided on the thermoelectric cooler 201 to increase the cooling range, maintain cooling, and as described above, when the side convex groove 204 and the side groove 203 and the top convex groove 202 and the bottom groove 205 are spliced with each other; also according to the formed shape contour of the workpiece, swing the top convex groove 202 and the side convex groove 204 at an angle with the thermoelectric cooler 201 based on the rotating shaft 206, so that it fits the processing path of the workpiece better, and then cooperate with the high thermal conductivity silicone rubber 211 to fit on the surface of the workpiece to improve contact, so as to obtain a more precise and better heat conduction and heat dissipation cooling effect;

[0054] g In step f, according to the partition cooling device 1 and after assembling the interlayer cooling device 2 above the second layer, turn off those that do not play a role in cooling and temperature reduction.

[0055] Reference Figures 1-2An extended multi-modal additive manufacturing cooling system shown in the figure includes a partition cooling device 1 and an interlayer cooling device 2, and an external DC power supply 209 is provided to supply energy. The partition cooling device 1 includes a heat-conducting flow channel plate 102, a base platform 101, and a transition water tank 109. A substrate 302 and a plate fixing device 304 for installing the substrate 302 are fixed on the heat-conducting flow channel plate 102. There are vertically and horizontally intersecting cooling channels 110 inside the heat-conducting flow channel plate 102, and controllable solenoid valves 113 are installed at the flow channel intersection nodes. The partition cooling device 1 includes a cooling pipeline 104, a pressure pump 103 installed at the platform water inlet 106 and the platform water outlet 105, and a conduction pipe 107 connected between the pressure pump 103 and the transition water tank 109. A water change port 112 is arranged on the end face of the transition water tank 109.

[0056] Reference Figures 4-6 As shown in the figure, the interlayer cooling device 2 includes a thermoelectric cooler 201, a heat dissipation plate 210, and high thermal conductivity silicone 211. The thermoelectric cooler 201 is arranged in a thermoelectric cooling component housing 212. The thermoelectric cooling component housing 212 wraps the peripheral position except the working end face of the thermoelectric cooler 201, and a top convex groove 202, a bottom concave groove 205, a side convex groove 204, and a side concave groove 203 are provided. The thermoelectric cooler 201 includes a refrigeration end face 207 and a heating end face 208. The outside of the refrigeration end face 207 is wrapped with high thermal conductivity silicone 211, and the heat dissipation plate 210 is installed outside the heating end face 208. The thermoelectric cooler 201 is provided with an interface for an external DC power supply 209.

[0057] Reference Figures 1-3In the above structure, the heat conduction channel plate 102 in the partition cooling device 1 is a rectangular parallelepiped with a plurality of connecting holes on the front and rear end faces and the left and right end faces for setting the cooling channel 110. The number of connecting holes and the radius size can be determined according to the specific situation of the heat conduction channel plate 102. The present invention adopts copper material, which has good thermal conductivity and can effectively conduct the heat of the substrate 302 during the material addition process to the cooling water inside the cooling channel 110. The connecting holes in the heat conduction channel plate 102 intersect vertically and horizontally to form nodes, and the node parts are installed There is a controllable solenoid valve 113, which can partially block and circulate the internal passage of the cooling channel 110 according to the relative position of the substrate 302 and the heat conduction channel plate 102. Fixed through holes arranged in different numbers are arranged on the upper and lower end faces of the heat conduction channel plate 102, and the number is determined by the actual situation. The connecting holes on the front and rear end faces and the left and right end faces are arranged in a grid shape inside the heat conduction channel plate 102, and can intersect to form nodes. The through holes on the upper and lower end faces are opened in the middle of the grid area and cannot intersect with the channel, thereby realizing the cooling and fixing functions of the substrate 302 respectively. The pipes connected to the platform water outlet of the heat conduction runner plate 102 are all cooling pipes 104. The diameter of the pipe can be determined according to the diameter of the platform water outlet. The wall thickness is 2mm and the material is copper. The length can be determined by the relative position of the pressure pump 103 and the platform water outlet to prevent the cooling water inside the heat conduction runner plate 102 from bringing out too much heat and affecting the pipe during material addition. The other end of the cooling pipe 104 is connected to the pressure pump 103. The pressure pump 103 and the transition water tank 109 are connected by the conducting pipe 107. The water replacement port 112 provided on the end face of the transition water tank 109 can be replaced according to the degree of cooling water usage.

[0058] In this embodiment, Figure 3 The heat conduction channel plate 102 shown in the figure is provided with crisscross cooling channels 110, and an adjustable controllable solenoid valve 113 is installed at the intersection of the channels. By adjusting the controllable solenoid valve 113, the water flow in the corresponding four directions of the channel at the intersection is achieved, and the targeted zoning and shaping cooling channel 110 is adjusted. The valve ports of the corresponding controllable solenoid valve 113 at the bottom of the substrate 302 are all opened to ensure the cooling of the cooling channel 110. The controllable solenoid valve 113 of the cooling channel 110 adjacent to the substrate 302 is opened toward the substrate 302, and closed in the opposite direction, thereby achieving effective cooling of the bottom area of ​​the substrate 302 of different shapes and sizes, realizing the zoning and shaping cooling function in the basic mode, and providing temperature buffer for the upper cooling. The schematic diagram of the cooling water flow in the cooling channel 110 according to the placement position of the substrate 302 in the example is shown as follows Figure 3 As shown by the dashed line with an arrow; further, refer to Figure 3Two sets of circuits are formed. The circuit in the lower left corner can be used to cool workpieces with a relatively low stacking height, while the one on the right is suitable for workpieces with a better stacking height. The purpose is that the stacking method of the additive manufacturing process is layer-by-layer stacking. For the lower-layer workpieces, each time a layer is stacked, they need to be heated again relative to the lower layer. When encountering an integrated workpiece with different layer heights, the temperatures of the workpieces in the lower-layer area and the higher-layer area are different. The locally partitioned and independently coordinated heat dissipation method adopted in the present invention can reduce the overall temperature difference of the workpiece, so that the temperature of the workpiece is uniform during the processing, avoiding the problem of performance differences between regions of the same workpiece due to temperature differences. In addition, the present invention adopts a controllable solenoid valve 113 device. Therefore, during the processing, according to the program control, the circuit can also be changed. For example, in the signal fed back by the sensor, if the temperature of some areas of the workpiece is too high, this requires a dense circuit to accelerate the temperature cooling to improve the cooling effect, that is, by sending a command through the program to control the controllable solenoid valve 113 to adjust the circuit, which can be changed and switched at any time to meet the processing requirements.

[0059] Figures 4-9 In the interlayer cooling device 2 of the above-mentioned structure, the thermoelectric cooler 201 is made by arranging two different metals in a certain way and then energizing them using the Peltier effect. After being energized, the thermoelectric cooler 201 will form a refrigerating end face and a heating end face. The thermoelectric cooler 201 is embedded in the thermoelectric cooling component housing 212 except for the periphery of the working surface. See Figures 6-7 At the top and side of the thermoelectric cooling component housing 212 of the present invention, a rotating shaft 206 is assembled to drive the top groove and the side groove to rotate, so that the groove can be spliced with the groove to realize the adjustable function of the interlayer cooling device. The splicing quantity and adjustment angle of the splicable and adjustable interlayer cooling device 2 will be determined according to specific conditions. The dynamic module will splice and place the single interlayer cooling device 2 on both sides of the path in a path-following manner to realize local precise cooling of complex paths. The adjustable interlayer cooling device 2 for the curved path is connected and assembled by using Figures 4-6 the structure.

[0060] In this embodiment, as Figure 5In the interlayer cooling device 2 shown, the high thermal conductivity silicone 211 is wrapped outside the cooling end face 207 of the thermoelectric cooler 201 and is in direct contact with the additive component 303 for cooling. The heat dissipation plate 210 is fixedly assembled on the heating end face 208 but not in contact with the end face. The high thermal conductivity silicone 211 directly takes away the heat inside the additive component 303, and the heat is consumed by contacting the cooling end face 207. During the energization process, the heat generated on the heating end face 208 will be discharged into the air with the assistance of the heat dissipation plate 210, realizing an environmentally friendly cooling method that is pollution-free to the arc and pollution-free to the air. The thermoelectric coolers 201 are connected in parallel to the external DC power supply 209, enabling each thermoelectric cooler 201 to cool independently; the heat dissipation plates 210 at the hot ends of the thermoelectric coolers 201 are powered by independent power supplies. The rated input voltage of the thermoelectric cooler is 12V, the rated cooling power is 180W, and the maximum temperature difference between the cooling end face and the hot end face is 63°C; the convex groove contains a rotating shaft 206 inside, and the rotating shaft 206 adjusts the angle of the convex groove to adjust the angular deflection of the thermoelectric cooler 201 to achieve the purpose of corner and curved surface cooling.

[0061] In the description of the present invention, it should be noted that the terms "vertical", "horizontal", "upper", "lower", "front", "rear", "left", "right", "top", "bottom", etc. indicating the orientation or positional relationship are based on the orientation or positional relationship shown in the drawings. 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 or operated in a specific orientation, so it cannot be understood as a limitation to the present invention. In addition, the terms "first", "second", "third" are only used for descriptive purposes and cannot be understood as indicating or implying relative importance.

[0062] In the description of the present invention, it should be noted that unless otherwise clearly specified and limited, the terms "installed", "connected", "connected" 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 mechanical connection or an electrical connection; it can be a direct connection or an indirect connection through an intermediate medium, and it can be the communication inside two elements. 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. In addition, in the description of the present invention, unless otherwise stated, the meaning of "multiple" is two or more.

[0063] All technicians should note that although the present invention has been described according to the above specific embodiments, the inventive concept of the present invention is not limited to this invention. Any modification using the inventive concept of the present invention will be included in the scope of protection of the patent right of this patent.

[0064] The above are only the preferred embodiments of the present invention, and the protection scope of the present invention is not limited to the above embodiments. All technical solutions falling within the concept of the present invention belong to the protection scope of the present invention. It should be noted that for those of ordinary skill in the art, several improvements and refinements made without departing from the principle of the present invention should also be regarded as within the protection scope of the present invention.

Claims

1. A cooling system for extended multi-modal additive manufacturing, characterized in that: include: A partitioned cooling device (1), the partitioned cooling device (1) being a basic mode constructed by a base platform (101) and a heat conduction channel plate (102), the heat conduction channel plate (102) being arranged on the base platform (101), a connected cooling channel (110) being arranged inside the heat conduction channel plate (102), a node being formed at the intersection of the cooling channel (110), an adjustable and controllable electromagnetic valve (113) being arranged at the node position, and a pressure pump (103) being arranged on the base platform (101) to control the pressure of the cooling channel (110). and a transition water tank (109); one end of the pressure pump (103) is provided with a connecting pipe (107) connected to the transition water tank (109); the other end is provided with a cooling pipe (104) connected to the cooling channel (110); the other end of the cooling channel (110) is connected to the transition water tank (109) for liquid return; the transition water tank (109) forms a cooling water circulation by relying on the pressure pump (103), the cooling pipe (104), the connecting pipe (107) and the cooling channel (110) in the heat conduction channel plate (102); An interlayer cooling device (2) is an assembled dynamic mode, comprising a rectangular vertically connectable square structure with an embedded thermoelectric cooler (201) in the middle, the adjacent sides of the square structure being provided with trapezoidal groove splicing interfaces, and the adjacent sides of the square structure being provided with corresponding trapezoidal convex splicing interfaces, and the adjacent side splicing combination of the interlayer cooling device (2) is used to form interlayer cooling along a manufacturing path.

2. The cooling system for extended multi-modal additive manufacturing according to claim 1, characterized in that: The cooling channels (110) arranged in the heat-conducting channel plate (102) are interconnected in a cross-shaped manner, wherein a node is formed at the intersection of the two directions. A controllable electromagnetic valve (113) for regulating the flow direction of cooling water in the channel is arranged at the node position. The heat-conducting channel plate (102) is also provided with a mounting hole for fixing a manufacturing substrate (302). Heat in the manufacturing process is conducted from the substrate (302) to the heat-conducting channel plate (102), and then the heat is dispersed through the cooling channel (110) inside the heat-conducting channel plate (102) to cool the heat-conducting channel plate (102).

3. The cooling system for extended multi-modal additive manufacturing according to claim 2, characterized in that: The controllable electromagnetic valve (113) arranged on the heat conduction channel plate (102) is provided with four valve ports to control the flow direction of water inside the cooling channel (110). The controllable electromagnetic valve (113) is used to adjust the opening according to the fixed position of the substrate (302), so that the heat conduction channel plate (102) forms a completely closed cooling channel (110) inside the position below the substrate (302). The valve ports of the controllable electromagnetic valve (113) located around the substrate (302) facing away from the substrate (302) are all closed, and the valve ports facing the substrate (302) are selectively opened according to the designed cooling channel (110) path, thereby realizing a basic modal cooling function with zoned and shaped adjustment.

4. The cooling system for extended multi-modal additive manufacturing according to claim 1, characterized in that: A mounting frame (108) is also provided inside the base platform (101), and the pressure pump (103) is fixed on the mounting frame (108). The cooling pipe (104) connected to one side of the pressure pump (103) and the conducting pipe (107) on the other side are connected to a transition water tank (109). By driving the pressure pump (103), cooling water is drawn out from the transition water tank (109) and brought into the heat conduction channel plate (102) through the cooling pipe (104), and then brought back to the transition water tank (109) through the cooling pipe (104) at the opposite heat conduction channel plate (102), thereby realizing circulating cooling.

5. The cooling system for extended multi-modal additive manufacturing according to claim 1, characterized in that: The thermoelectric cooler (201) adopts the Peltier effect and forms a cooling end surface (207) and a heating end surface (208) by providing an external DC power supply (209); the outer side of the cooling end surface (207) is wrapped with a high thermal conductivity silica gel (211), and the outer side of the heating end surface (208) is equipped with a heat sink (210).

6. The cooling system for extended multi-modal additive manufacturing according to claim 5, characterized in that: The interlayer cooling device (2) also includes a thermoelectric cooling component housing (212) covering the outside of the thermoelectric cooling device (201); the high thermal conductivity silicone rubber (211) and the heat sink (210) are arranged on two side surfaces of the thermoelectric cooling component housing (212); the high thermal conductivity silicone rubber (211) directly contacts the cooling end surface (207); and the heat sink (210) is arranged and fixed on the thermoelectric cooling component housing (212) at a distance from the heating end surface (208).

7. The cooling system for extended multi-modal additive manufacturing according to claim 6, characterized in that: The thermoelectric cooling component housing (212) is provided with opposite side grooves (203) and side convex grooves (204) and top convex grooves (202) and bottom grooves (205), and is installed in a vertical position. The thermoelectric cooler (201) is symmetrically placed on the manufacturing substrate (302) along the two sides of the manufacturing path through the side grooves (203) and side convex grooves (204) and top convex grooves (202) and bottom grooves (205). The manufacturing path is reserved in the middle of the cooling end surface (207) for the arc welding gun (301) to move. The manufacturing path is used to adjust the placement position of the thermoelectric cooler (201) to achieve local precise cooling of complex paths.

8. The cooling system for extended multi-modal additive manufacturing according to claim 7, characterized in that: The top convex groove (202) and the side convex groove (204) are both provided with a rotating shaft (206), and the rotating shaft (206) is used to adjust the swing angle between two adjacent thermoelectric coolers (201) in the horizontal and vertical directions to fit the manufacturing path by rotating the rotating shaft (206) when the interlayer cooling device (2) is assembled.

9. A method for suppressing stress in a cooling system for extended multi-modal additive manufacturing, characterized in that: The following steps are involved: a. fixing the substrate (302) on the heat conduction channel plate (102) in advance and planning a simulated material addition path; b Additive material preparation, first, prepare the manufacturing consumables and adjust the welding gun (301) conductive nozzle; The ion gas and shielding gas required by the welding gun (301) are connected according to conventional methods; the welding gun (301) travels an empty path and the path is recorded; c. adjusting the controllable electromagnetic valve (113) according to the fixed position of the substrate (302) so that a closed loop is formed between the cooling channel (110) and the transition water tank (109) in the bottom area of ​​the substrate (302), and starting the pressure pump (103) to bring the cooling water of the transition water tank (109) into the heat conduction channel plate (102) through the cooling pipe (104), so as to cool the additive material at the bottom layer from below; d. After the height of the additive material exceeds the cooling range of the bottom layer, an interlayer cooling device (2) is placed outside the lower layer material that has been additively added and outside the lower layer workpiece. During the setting, the rotation of the rotating shaft (206) is used to control the swing fine adjustment between two adjacent thermoelectric coolers (201). The cooling end surface (207) of the thermoelectric cooler (201) is placed along the manufacturing path and in close contact with the surface of the semi-finished workpiece after the additive material is completed, so that the high thermal conductivity silicone rubber (211) of the cooling end surface (207) directly contacts the additive workpiece for heat conduction and cooling nearby. The thermoelectric cooler (201) is spliced ​​in multiple sections according to the length and height of the additive material to be performed next according to the simulation path to ensure the manufacturing effect. e. Manufacturing process: First, the substrate (302) is preheated. According to the preset manufacturing path, the welding gun (301) is controlled to reach the specified position to start additive material. At the same time, the pressure pump (103) is started, and the partition cooling device (1) starts to work to cool the bottom product of the additive material of the substrate (302); f. When the height of the added material exceeds the height of the single-layer interlayer cooling device (2), the interlayer cooling device (2) is assembled and started to work in accordance with the method of step d, and cooling is performed by the thermoelectric cooler (201) attached to the lower workpiece. When the height of the added material exceeds the single-layer cooling range of the single-layer interlayer cooling device (2), the top convex groove (202) and the bottom surface groove (205) are continued to be spliced ​​upward to increase the cooling range and maintain the cooling; g. In step f, according to the partitioned cooling device (1) and after assembling the interlayer cooling device (2) above the second layer, the cooling device that does not play a cooling role can be closed.

10. The stress suppression method of a cooling system for extended multi-modal additive manufacturing according to claim 9, characterized in that: The closed loop in step c is formed by setting a plurality of closed loops according to the stacking height of the additive material, and the density of the closed loops is proportional to the number of stacking layers, so as to maintain a uniform and balanced temperature of the additive workpiece.

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