Laser additive manufacturing system and method for in-situ self-adaptive regulation and control of component shape through temperature field and airflow field

Abstract

The invention discloses a laser additive manufacturing system and method for in-situ self-adaptive regulation and control of the component shape through a temperature field and an airflow field. The laser additive manufacturing system comprises a sealed protection cavity, a master control unit, a temperature field monitoring-control unit and an airflow field monitoring-control unit. The temperature field monitoring-control unit comprises an infrared thermometer, a thermocouple temperature measuring element and an induction heating coil; and the airflow field monitoring-control unit comprises a protective gas pipeline, an electromagnetic flow regulating valve, an oxygen content monitor and a vacuum air filter. The master control unit comprises a temperature field control module and an airflow field control module. The master control unit conducts in-situ self-adaptive regulation and control on the temperature field of laser additive manufacturing through the temperature field control module, distribution of the temperature field in the whole process of additive manufacturing is improved, the temperature gradient of a molten pool in the laser additive manufacturing process is reduced, the forming defect is improved, and the material performance is improved.

Description

Technical Field

[0001] The invention relates to a laser additive manufacturing system that adaptively regulates the shape of a component in situ through a temperature field and an airflow field, and belongs to the field of additive manufacturing. Background Art

[0002] Additive manufacturing is a manufacturing technology based on computer-aided design model data and realized by layer-by-layer accumulation of materials. Compared with traditional subtractive manufacturing, additive manufacturing is a "bottom-up" manufacturing technology that can effectively shorten the product development cycle, has huge application potential, and is developing rapidly. Additive manufacturing of metal components is an important application direction in this field. During the additive manufacturing process of metal components, the metal melt undergoes a cycle of repeated heating and cooling under the action of the laser beam, and heat will continue to be generated and diffused. Components of different shapes will have different heat accumulation effects during the forming process, resulting in inconsistent internal properties of the components, uneven organization, coarse organization, and serious component segregation, which increases the difficulty of regulating the organizational properties of the components and customized manufacturing of local performance. Specifically, before the start of additive manufacturing, if the surface temperature of the substrate is too low, it is very easy to cause defects in the forming of the formed part and affect the processing indicators; after the additive manufacturing process is completed, the surface of the component still maintains a high temperature. Without protection, it is very easy to be contaminated or oxidized by active components in the surrounding environment. The existing technology has a very limited effect on the control of component temperature. Therefore, a temperature field control device for components is needed so that the temperature of the printed part before processing can meet the requirements. After additive manufacturing printing, the surface temperature of the formed part can be maintained at a certain temperature, or gradually cooled in the form of a certain temperature step to achieve an effect similar to heat treatment. Summary of the invention

[0003] The purpose of the present invention is to provide a laser additive manufacturing system that can adaptively control the shape of components through temperature field and airflow field in situ. The system applies auxiliary thermal field and airflow field from a process perspective to the existing laser directional energy deposition technology, and controls temperature changes according to specific implementation requirements, thereby realizing the regulation of the temperature field in the entire additive manufacturing process, improving the distribution of the temperature field in the entire additive manufacturing process, reducing the temperature gradient of the molten pool in the laser additive manufacturing process, improving forming defects, and enhancing material properties.

[0004] In order to achieve the above technical objectives, the present invention will adopt the following technical solutions:

[0005] A laser additive manufacturing system for in-situ adaptively regulating the shape of a component through a temperature field and an airflow field comprises a sealed protection cavity, a general control unit, a temperature field monitoring-control unit and an airflow field monitoring-control unit; wherein:

[0006] The temperature field monitoring-control unit comprises an infrared thermometer, a thermocouple temperature measuring element and an induction heating coil; the infrared thermometer is installed through the sealed protection cavity, and is used to detect the temperature in the sealed protection cavity and can transmit the detected temperature information to the main control unit; the thermocouple temperature measuring element is installed on the substrate, and is used to detect the temperature of the substrate and can transmit the detected temperature information to the main control unit; the induction heating coil is placed in the sealed protection cavity and is arranged around the substrate;

[0007] The airflow field monitoring-control unit includes a protective gas pipeline, an electromagnetic flow regulating valve, an oxygen content monitor and a vacuum air filter; the protective gas pipeline is arranged in a sealed protective cavity, and the protective gas pipeline runs through the sealed protective cavity and is respectively provided with an external air inlet interface and an external air outlet interface, the external air inlet interface is connected to the air outlet of the protective gas cylinder through a protective gas output pipeline, and an electromagnetic flow regulating valve is installed on the external air inlet interface, and the external air outlet interface is connected to the air return port of the protective gas cylinder through a protective gas recovery pipeline, and a vacuum air filter and an oxygen content monitor are installed on the external air outlet interface according to the order of airflow direction;

[0008] An electromagnetic flow regulating valve is used to detect the flow of shielding gas in the shielding gas input pipeline and can transmit the detected shielding gas flow information to the main control unit;

[0009] An oxygen content monitor is used to detect the oxygen content of the shielding gas output by the shielding gas pipeline, and can transmit the detected oxygen content information of the shielding gas to the main control unit;

[0010] The general control unit includes a temperature field control module and an air flow field control module;

[0011] The airflow field control module determines whether the oxygen content in the sealed protection cavity has reached a safe range based on the oxygen content information of the protective gas fed back by the oxygen content monitor. When the judgment result shows that the oxygen content in the sealed protection cavity has reached a safe range, the electromagnetic flow regulating valve is closed and the temperature field control module is triggered;

[0012] The temperature field control module includes five temperature judgment submodules, corresponding to the first to fifth temperature judgment submodules;

[0013] The first temperature judgment submodule can judge whether the current temperature of the substrate needs to be kept warm according to the temperature information fed back by the thermocouple temperature measuring element. If the judgment result shows that the current temperature of the substrate needs to be kept warm, the current situation is maintained unchanged, and the timing and keeping warm module is triggered to start timing the duration of the substrate keeping warm until the duration of the substrate keeping warm reaches a preset time, thereby triggering the fifth temperature judgment submodule; otherwise, the second temperature judgment submodule is triggered;

[0014] The second temperature judgment submodule can judge whether the current temperature of the substrate needs to be quickly cooled according to the temperature information fed back by the thermocouple temperature measuring element. If the judgment result shows that the current temperature of the substrate needs to be quickly cooled, a first execution instruction is sent to the airflow field monitoring-control unit to open the electromagnetic flow regulating valve, input the protective gas into the sealed protective cavity, and trigger the fourth temperature judgment submodule; otherwise, the third temperature judgment submodule is triggered;

[0015] The third temperature judgment submodule can judge whether the current temperature of the substrate needs to be heated according to the temperature information fed back by the thermocouple temperature measuring element. If the judgment result shows that the current temperature of the substrate needs to be inductively heated, a second execution instruction is sent to the temperature field monitoring-control unit to turn on the induction coil heating and trigger the fourth temperature judgment submodule; otherwise, a third execution instruction is sent to the temperature field monitoring-control unit to turn off the induction coil and trigger the fourth temperature judgment submodule.

[0016] The fourth temperature judgment submodule can judge whether the current temperature of the substrate reaches the second preset temperature range according to the temperature information fed back by the thermocouple temperature measuring element. If the judgment result shows that the current temperature of the substrate reaches the second preset temperature range, the fifth temperature judgment submodule is triggered; otherwise, the first temperature judgment submodule is triggered.

[0017] The fifth temperature judgment submodule is used to judge whether the temperature information fed back by the infrared thermometer reaches the first preset temperature range. If the judgment result shows that the temperature information fed back by the infrared thermometer is within the first preset temperature range, the temperature field of the entire laser additive manufacturing process is controlled; otherwise, the first temperature judgment submodule is triggered.

[0018] Preferably, the thermocouple temperature measuring elements include several thermocouple temperature measuring elements, one of which is arranged at the middle position of the substrate, and the remaining thermocouple temperature measuring elements are evenly arranged around the substrate.

[0019] Preferably, it comprises a laser directed energy deposition system, which comprises a robotic arm, a laser, a powder feeder, a water cooler and a laser additive manufacturing cladding head;

[0020] One end of the laser additive manufacturing cladding head is connected to the power output end of the robot arm, and the other end extends into the sealed protection cavity and is sealedly connected to the sealed protection cavity;

[0021] The laser additive manufacturing cladding head is provided with a powder feeding channel, a water cooling channel and a laser light channel; the laser light channel is connected to the laser through a laser transmission optical fiber; the water cooling channel is connected to the output end of the water cooler; and the powder feeding channel is connected to the output end of the powder feeder.

[0022] Preferably, the sealed protection cavity comprises a cover plate, a transparent high temperature resistant protective film, high temperature resistant gloves, an inspection window, a sealed protection cavity body and a fixing fixture for a cladding head, wherein:

[0023] The sealing protection cavity body is placed on a working platform and clamped by a mechanical fixing fixture provided on the working platform;

[0024] The high temperature resistant gloves and the inspection window are fixed to the pre-opened sealing protection cavity body through a sealing flange connection;

[0025] The transparent high temperature resistant protective film is fixed on the main body of the sealed protective cavity;

[0026] The cover plate is arranged above the transparent high temperature resistant protective film and is clamped by a spring pre-tightening buckle and a sealing protective cavity body;

[0027] The infrared thermometer is installed on the cover plate close to the inspection window, and the detection head of the infrared thermometer can detect the temperature in the sealed protection cavity through the inspection window.

[0028] Preferably, the transparent high-temperature resistant protective film is designed into a regular hexagon according to the movement requirements of the laser additive manufacturing cladding head, and is folded into a pyramid-shaped quadrangular pyramid during installation; the top of the transparent high-temperature resistant protective film is reserved with an opening that can just pass through the laser additive manufacturing cladding head, and is fixed to the laser additive manufacturing cladding head by a cladding head fixing fixture, the cladding head fixing fixture includes eight completely identical clamping bodies that are clamped in pairs, and adjacent clamping bodies are connected by bolts. At the same time, rubber sealing gaskets that just pass through the laser additive manufacturing cladding head are placed between adjacent clamping bodies, and a circular opening for passing a powder feeder pipeline and a water cooling pipeline is pre-opened on the surface of the cladding head fixing fixture according to actual working requirements.

[0029] Preferably, the thickness of the transparent high temperature resistant protective film is 0.3 mm.

[0030] Preferably, a scraper is installed in the center of the inspection window, and the scraper is mechanically connected to a handle on the outside of the inspection window.

[0031] Another technical purpose of the present invention is to provide a laser additive manufacturing method for in-situ adaptively regulating the shape of a component by temperature field and airflow field, which is realized based on the above-mentioned laser additive manufacturing system for in-situ adaptively regulating the shape of a component by temperature field and airflow field, and comprises the following steps:

[0032] Step 1: Turn on the airflow field monitoring-control unit to input protective gas into the sealed protective cavity to achieve deoxygenation operation of the sealed protective cavity;

[0033] Step 2: Detect the oxygen content in the sealed protection cavity by an oxygen content detector until the oxygen content in the sealed protection cavity detected by the oxygen content detector reaches a safe range, close the electromagnetic flow regulating valve, and stop inputting protective gas into the sealed protection cavity;

[0034] Step 3: Turn on the temperature field monitoring-control unit to adaptively control the temperature field of the entire laser additive manufacturing process in situ, which specifically includes the following steps:

[0035] Step 3.1, judging whether the current temperature of the substrate needs to be kept warm according to the temperature information detected by the thermocouple temperature measuring element; when the judgment result shows that the current temperature of the substrate needs to be kept warm, the current state is maintained unchanged, and the timing and heat preservation module is started to time the duration of the substrate heat preservation state, and step 3.5 is entered at the same time; otherwise, step 3.2 is entered;

[0036] Step 3.2, judging whether the current temperature of the substrate needs to be quickly cooled; when the judgment result shows that the current temperature of the substrate needs to be quickly cooled, turning on the airflow field monitoring-control unit, opening the electromagnetic flow regulating valve, so as to input the protective gas into the sealed protective cavity, and then entering step 3.4; otherwise, entering step 3.3;

[0037] Step 3.3, judging whether the current temperature of the substrate needs to be heated; when the judgment result shows that the current temperature of the substrate needs to be heated, the induction heating coil is turned on to induction heat the substrate, and then the process proceeds to step 3.4; otherwise, the induction heating coil is turned off and the process proceeds to step 3.4;

[0038] Step 3.4, judging in real time whether the current temperature of the substrate reaches the program setting temperature; when the judgment result shows that the current temperature of the substrate reaches the program setting temperature, proceed to step 3.5, otherwise, return to step 3.1;

[0039] Step 3.5: Determine in real time whether the temperature in the sealed protective cavity has reached the preset temperature path end point; when the judgment result shows that the temperature in the sealed protective cavity has reached the preset temperature path end point, the temperature field control of the entire laser additive manufacturing process is terminated; otherwise, return to step 3.1.

[0040] Based on the above technical objectives, the present invention has the following advantages over the prior art:

[0041] 1. The laser additive manufacturing system for in-situ adaptive regulation of component shape by temperature field described in the present invention can monitor the temperature of the box and the forming material in real time by two means at the same time, realize temperature field monitoring of the whole process of additive manufacturing, and feed back the results to the system in real time and present them intuitively through visualization software. According to the monitoring results, the system will autonomously adjust and control the temperature of the substrate to stabilize within a limited range, and adaptive temperature control can be achieved without direct operation, thereby reducing labor costs and reducing safety hazards.

[0042] 2. The laser additive manufacturing system for in-situ adaptive regulation of component shape by temperature field described in the present invention can change the temperature of the substrate and the inside of the box in a direction and quickly according to the needs of material forming. Starting from actual needs, by planning the temperature change path in advance, it can realize multiple functions such as preheating, heat preservation, heat treatment, and rapid cooling of the substrate, reduce the temperature difference between the printed component and the substrate, reduce the phenomenon of uneven structure, coarse structure and component segregation caused by excessive temperature difference, avoid the change of material shape caused by the influence of temperature field, thereby greatly improving the material forming quality, and providing a new idea for solving the problem of unstable material shape in laser directional energy deposition.

[0043] 3. The laser additive manufacturing system for in-situ adaptive regulation of component shape by temperature field described in the present invention can quickly cool the component through the airflow field of cooling gas after the printing process is completed, thereby reducing the oxidation caused by the surrounding atmosphere due to high temperature, thereby improving the surface quality of the formed component.

[0044] 4. The laser additive manufacturing system for in-situ adaptive regulation of component shape by temperature field described in the present invention can reduce the oxygen concentration of the entire environment to a reasonable range in a short time. The customized sealing fixture can be used to prevent leakage of protective gas, so that the device can effectively prevent the escape of protective gas, and the oxygen content is maintained at the same level for a long time. At the same time, the volume of the protection cavity is greatly reduced compared to the cabin used in the common laser directed energy deposition technology without hindering the movement of the mechanism, which greatly saves the material forming time and the amount of protective gas used, and reduces safety hazards. BRIEF DESCRIPTION OF THE DRAWINGS

[0045] Figure 1 It is a schematic diagram of the overall structure of the laser additive manufacturing system for in-situ adaptively regulating the shape of a component through a temperature field and an airflow field according to the present invention;

[0046] In the figure: 1. Laser directed energy deposition system; 2. Sealed protection chamber; 3. Temperature field monitoring-control unit; 4. Air flow field monitoring-control unit; 5. General control unit; 1.1. KUKA robot; 1.3. Powder feeder; 1.5. Laser additive manufacturing cladding head.

[0047] Figure 2 Schematic diagram of the laser additive manufacturing cladding head and the installation method of the transparent heat-resistant film;

[0048] In the figure: 2.2, transparent high temperature resistant protective film; 2.6, fixing fixture for cladding head; 1.5, laser additive manufacturing cladding head.

[0049] Figure 3 It is a schematic diagram of the internal structure of the sealing protection cavity;

[0050] In the figure: 2.1, cover plate; 2.2, transparent high temperature resistant protective film; 2.3, high temperature resistant gloves and flange; 2.4, inspection window; 2.5, sealed protective chamber body; 2.6, fixing fixture for cladding head; 3.1, infrared thermometer; 3.3, induction heating coil; 4.1 protective gas pipeline; 4.2, electromagnetic flow control valve; 4.3, oxygen content monitor; 4.4, air filter; 5.1, substrate for laser additive manufacturing; 5.2, magnetic fixing fixture;

[0051] Figure 4 Program flowchart of temperature field and temperature field control system. DETAILED DESCRIPTION

[0052] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, rather than all the embodiments. The following description of at least one exemplary embodiment is actually only illustrative and is by no means any limitation to the present invention and its application or use. Based on the embodiments in the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention. Unless otherwise specified, the relative arrangement, expressions and numerical values ​​of the components and steps described in these embodiments do not limit the scope of the present invention. The techniques, methods and equipment known to ordinary technicians in the relevant fields may not be discussed in detail, but in appropriate cases, the techniques, methods and equipment should be regarded as part of the specification. In all examples shown and discussed here, any specific value should be interpreted as merely exemplary, rather than as a limitation. Therefore, other examples of the exemplary embodiments may have different values.

[0053] For ease of description, spatially relative terms such as "above", "above", "on the upper surface of", "above", etc. may be used here to describe the spatial positional relationship between a device or feature and other devices or features as shown in the figure. It should be understood that spatially relative terms are intended to include different orientations of the device in use or operation in addition to the orientation described in the figure. For example, if the device in the accompanying drawings is inverted, the device described as "above other devices or structures" or "above other devices or structures" will be positioned as "below other devices or structures" or "below other devices or structures". Thus, the exemplary term "above" can include both "above" and "below". The device can also be positioned in other different ways (rotated 90 degrees or in other orientations).

[0054] like Figure 1 As shown, the laser additive manufacturing system for in-situ adaptive regulation of component shape by temperature field of the present invention comprises: a laser directed energy deposition system, a sealed protection cavity, a temperature field monitoring-control unit, an airflow field monitoring-control unit and a general control unit, wherein:

[0055] The laser directed energy deposition system described in the present invention comprises a robotic arm (the present invention uses a KUKA robot), a laser, a powder feeder, a water cooling mechanism and a laser additive manufacturing cladding head. The laser additive manufacturing cladding head is fixed to the front end of the KUKA robot. The laser generated by the laser is output to the laser additive manufacturing cladding head through a laser transmission optical fiber. The high temperature of the laser is used to melt the powder. The KUKA robot moves along a set path to deposit the molten metal powder layer by layer onto a special substrate for additive manufacturing. The water cooling mechanism provides cooling for the laser additive manufacturing cladding head to prevent overheating and damage to the cladding head.

[0056] The sealing protection cavity is made of stainless steel. Figure 3As shown, it includes a sealed protection chamber body, a cover plate, a transparent high-temperature resistant protective film, high-temperature resistant gloves, an inspection window, a temperature field monitoring-control unit, and an airflow field monitoring-control unit. The sealed protection chamber body is made of stainless steel, and holes are opened on the surface for installing other components; the high-temperature resistant gloves are fixed to the sealed protection chamber body through a flange, and the movable range of the high-temperature resistant gloves is greater than or equal to the length of the long side of the inner wall of the sealed protection chamber body; the inspection window is fixed to the sealed protection chamber body through a flange, and the glass used for the inspection window is a special material that can reduce interference with infrared light and improve the accuracy of the temperature measurement system. A scraper that can rotate along the axis is installed in the center of the inspection window to prevent smoke and dust generated during the additive manufacturing process from obstructing observation; the protective gas pipeline in the airflow field monitoring-control unit passes the protective gas flow from the protective chamber body through the holes reserved on the sealed protection chamber body. The gas cylinder is conducted to the main body of the sealed protection chamber, the protective gas pipeline is fixed on the main body of the sealed protection chamber, and the oxygen content monitor is suspended on the surface of the main body of the sealed protection chamber. It can be moved by hand according to the use requirements to observe the changes in oxygen content; the thermocouple temperature measuring element used to monitor the temperature of the substrate in the temperature field monitoring-control unit needs to be adjusted according to the position of the substrate, and is fixed to the center and around the substrate by a clamp. At the same time, the infrared detector for monitoring the temperature of the closed protection cavity is fixed at the key position of the cavity and does not need to be moved frequently; the induction heating unit is fixed in the main body of the sealed protection chamber and does not contact the surface of the main body of the sealed protection chamber. The wires are connected to the main control unit through the reserved holes on the surface of the main body of the sealed protection chamber.

[0057] The sealed protection chamber body should be assembled in a fixed order before use: first use a level to calibrate the position of the sealed protection chamber body, and use a mechanical positioning fixture to fix the sealed protection chamber body on the work surface; open the hatch, adjust the position of the magnetic suction fixture according to the size of the special substrate for additive manufacturing used, and reserve appropriate space to prevent the substrate from being deformed due to heat, making it difficult to remove the substrate; adjust the position of the thermocouple temperature measuring element, and place it at the center and around the lower surface of the special substrate for additive manufacturing, and adjust the position of the induction heating element to avoid contact with the substrate to reduce safety hazards; place the transparent high-temperature resistant protective film according to Figure 2 The high temperature resistant protective film is folded in the order shown, and the high temperature resistant protective film is fixed with sealing tape around the main body of the sealing protection cavity, and the upper cover is installed and the metal pre-tightening buckles around it are closed; an opening is provided in the center of the high temperature resistant protective film to just accommodate the laser additive manufacturing cladding head, and the open end is fixed to the laser additive manufacturing cladding head by a cladding head fixing fixture, and the cladding head fixing fixture is composed of eight completely identical clamping splits, and there are non-standard sealing gaskets between the clamping splits that just pass through the laser additive manufacturing cladding head, and the adjacent clamping splits are connected by bolts. The installation structure of the cladding head fixing fixture is as shown in Figure 2 As shown, finally, the powder delivery pipe and the water cooling pipe are passed through the reserved holes on the surface of the cladding head fixing fixture; the cladding head is adjusted to a preset height and the hatch is tightly closed after ensuring that the installation sequence is correct.

[0058] The airflow field monitoring-control unit includes a protective gas pipeline, an electromagnetic flow control valve, an oxygen content detector, and an air filter. After the pre-processing is completed, the protective gas is manually turned on to start deoxygenation. The oxygen content monitor is located at the protective gas output end. When deoxygenation starts, the oxygen content monitor returns a signal to the master control system. If the oxygen content reaches a reasonable range, the electromagnetic flow control valve is automatically closed, and the temperature adjustment link is started to automatically adjust the oxygen content in the main body of the sealed protection cavity. When the oxygen content reaches the target value, the temperature change path is set according to the requirements of additive manufacturing. At the same time, when the surface temperature of the main body of the sealed protection cavity exceeds the safe temperature, the system will automatically start the cooling program, and quickly pass a large amount of protective gas whose temperature is far lower than the temperature in the main body of the sealed protection cavity to achieve safety protection.

[0059] The control system consists of three parts: real-time feedback from temperature sensors, system autonomous judgment and output of control instructions, and automatic closing and opening of mechanical elements according to instructions. According to the set temperature change path, adaptive control of the temperature field of the entire additive manufacturing printing process is achieved.

[0060] The temperature field monitoring-control unit is composed of an infrared thermometer, a thermocouple temperature measuring element, and an induction heating coil. The infrared thermometer is located outside the inspection window. When observing, it is necessary to manually adjust the scraper to scrape off the dust on the surface of the inspection window to prevent interference with the observation results. The results of the infrared thermometer are fed back to the general control system and intuitively reflected through the visualization software; the thermocouple temperature measuring elements located in the center and around the substrate feed back electrical signals to the general control system. When the control system determines that the temperature needs to be heated, the induction heating element is turned on to quickly heat the component and the substrate, and the next temperature control step is performed after the set temperature is reached; when the control system determines that the temperature needs to be cooled quickly, the airflow field control unit is turned on, and a protective gas far lower than the temperature in the cavity is quickly introduced into the cavity in a short time to quickly cool down; when the control system determines that the temperature reaches the program set temperature value, it enters the timing insulation module, and realizes the timing insulation function according to the set temperature path; the temperature change path of the system only needs to start setting the temperature change path throughout the process, so that the temperature field of the entire process of additive manufacturing printing can be adaptively controlled, so that the formed component can maintain a certain temperature for a long time, or gradually increase or decrease the temperature in the form of a certain temperature step, so as to achieve a similar effect of preheating or heat treatment.

[0061] Specifically, the general control unit of the present invention includes a temperature field control module and an air flow field control module;

[0062] The airflow field control module determines whether the oxygen content in the sealed protection cavity has reached a safe range based on the oxygen content information of the protective gas fed back by the oxygen content monitor. When the judgment result shows that the oxygen content in the sealed protection cavity has reached a safe range, the electromagnetic flow regulating valve is closed and the temperature field control module is triggered;

[0063] The temperature field control module includes five temperature judgment submodules, corresponding to the first to fifth temperature judgment submodules;

[0064] The first temperature judgment submodule can judge whether the current temperature of the substrate needs to be kept warm according to the temperature information fed back by the thermocouple temperature measuring element. If the judgment result shows that the current temperature of the substrate needs to be kept warm, the current situation is maintained unchanged, and the timing and keeping warm module is triggered to start timing the duration of the substrate keeping warm until the duration of the substrate keeping warm reaches a preset time, thereby triggering the fifth temperature judgment submodule; otherwise, the second temperature judgment submodule is triggered;

[0065] The second temperature judgment submodule can judge whether the current temperature of the substrate needs to be quickly cooled according to the temperature information fed back by the thermocouple temperature measuring element. If the judgment result shows that the current temperature of the substrate needs to be quickly cooled, a first execution instruction is sent to the airflow field monitoring-control unit to open the electromagnetic flow regulating valve, input the protective gas into the sealed protective cavity, and trigger the fourth temperature judgment submodule; otherwise, the third temperature judgment submodule is triggered;

[0066] The third temperature judgment submodule can judge whether the current temperature of the substrate needs to be heated according to the temperature information fed back by the thermocouple temperature measuring element. If the judgment result shows that the current temperature of the substrate needs to be inductively heated, a second execution instruction is sent to the temperature field monitoring-control unit to turn on the induction coil heating and trigger the fourth temperature judgment submodule; otherwise, a third execution instruction is sent to the temperature field monitoring-control unit to turn off the induction coil and trigger the fourth temperature judgment submodule.

[0067] The fourth temperature judgment submodule can judge whether the current temperature of the substrate reaches the second preset temperature range according to the temperature information fed back by the thermocouple temperature measuring element. If the judgment result shows that the current temperature of the substrate reaches the second preset temperature range, the fifth temperature judgment submodule is triggered; otherwise, the first temperature judgment submodule is triggered.

[0068] The fifth temperature judgment submodule is used to judge whether the temperature information fed back by the infrared thermometer reaches the first preset temperature range. If the judgment result shows that the temperature information fed back by the infrared thermometer is within the first preset temperature range, the temperature field of the entire laser additive manufacturing process is controlled; otherwise, the first temperature judgment submodule is triggered.

[0069] like Figure 3 As shown, the present invention discloses a laser additive manufacturing method for in-situ adaptively regulating the shape of a component through a temperature field and an airflow field, comprising the following steps:

[0070] Step 1: Turn on the airflow field monitoring-control unit to input protective gas into the sealed protective cavity to achieve deoxygenation operation of the sealed protective cavity;

[0071] Step 2: Detect the oxygen content in the sealed protection cavity by an oxygen content detector until the oxygen content in the sealed protection cavity detected by the oxygen content detector reaches a safe range, close the electromagnetic flow regulating valve, and stop inputting protective gas into the sealed protection cavity;

[0072] Step 3: Turn on the temperature field monitoring-control unit to adaptively control the temperature field of the entire laser additive manufacturing process in situ, which specifically includes the following steps:

[0073] Step 3.1, judging whether the current temperature of the substrate needs to be kept warm according to the temperature information detected by the thermocouple temperature measuring element; when the judgment result shows that the current temperature of the substrate needs to be kept warm, the current state is maintained unchanged, and the timing and heat preservation module is started to time the duration of the substrate heat preservation state, and step 3.5 is entered at the same time; otherwise, step 3.2 is entered;

[0074] Step 3.2, judging whether the current temperature of the substrate needs to be quickly cooled; when the judgment result shows that the current temperature of the substrate needs to be quickly cooled, turning on the airflow field monitoring-control unit, opening the electromagnetic flow regulating valve, so as to input the protective gas into the sealed protective cavity, and then entering step 3.4; otherwise, entering step 3.3;

[0075] Step 3.3, judging whether the current temperature of the substrate needs to be heated; when the judgment result shows that the current temperature of the substrate needs to be heated, the induction heating coil is turned on to induction heat the substrate, and then the process proceeds to step 3.4; otherwise, the induction heating coil is turned off and the process proceeds to step 3.4;

[0076] Step 3.4, judging in real time whether the current temperature of the substrate reaches the program setting temperature (the program setting temperature refers to the second preset temperature range); when the judgment result shows that the current temperature of the substrate reaches the program setting temperature, proceed to step 3.5, otherwise, return to step 3.1;

[0077] Step 3.5, determine in real time whether the temperature in the sealed protection cavity has reached the preset temperature path end point (the preset temperature path end point refers to the first preset temperature range); when the judgment result shows that the temperature in the sealed protection cavity has reached the preset temperature path end point, the temperature field control of the entire laser additive manufacturing process is ended, otherwise, return to step 3.1.

[0078] Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the present invention are included in the protection scope of the present invention.

Claims

1. A laser additive manufacturing system for in-situ adaptively regulating the shape of a component through a temperature field and an airflow field, comprising a sealed protective cavity and a general control unit, characterized in that: It also includes a temperature field monitoring-control unit and an airflow field monitoring-control unit; wherein: The temperature field monitoring-control unit comprises an infrared thermometer, a thermocouple temperature measuring element and an induction heating coil; the infrared thermometer is installed through the sealed protection cavity, and is used to detect the temperature in the sealed protection cavity and can transmit the detected temperature information to the main control unit; the thermocouple temperature measuring element is installed on the substrate, and is used to detect the temperature of the substrate and can transmit the detected temperature information to the main control unit; the induction heating coil is placed in the sealed protection cavity and is arranged around the substrate; The airflow field monitoring-control unit includes a protective gas pipeline, an electromagnetic flow regulating valve, an oxygen content monitor and a vacuum air filter; the protective gas pipeline is arranged in a sealed protective cavity, and the protective gas pipeline runs through the sealed protective cavity and is respectively provided with an external air inlet interface and an external air outlet interface, the external air inlet interface is connected to the air outlet of the protective gas cylinder through a protective gas output pipeline, and an electromagnetic flow regulating valve is installed on the external air inlet interface, and the external air outlet interface is connected to the air return port of the protective gas cylinder through a protective gas recovery pipeline, and a vacuum air filter and an oxygen content monitor are installed on the external air outlet interface according to the order of airflow direction; An electromagnetic flow regulating valve is used to detect the flow of shielding gas in the shielding gas input pipeline and can transmit the detected shielding gas flow information to the main control unit; An oxygen content monitor is used to detect the oxygen content of the shielding gas output by the shielding gas pipeline, and can transmit the detected oxygen content information of the shielding gas to the main control unit; The general control unit includes a temperature field control module and an air flow field control module; The airflow field control module determines whether the oxygen content in the sealed protection cavity has reached a safe range based on the oxygen content information of the protective gas fed back by the oxygen content monitor. When the judgment result shows that the oxygen content in the sealed protection cavity has reached a safe range, the electromagnetic flow regulating valve is closed and the temperature field control module is triggered; The temperature field control module includes five temperature judgment submodules, corresponding to the first to fifth temperature judgment submodules; The first temperature judgment submodule can judge whether the current temperature of the substrate needs to be kept warm according to the temperature information fed back by the thermocouple temperature measuring element. If the judgment result shows that the current temperature of the substrate needs to be kept warm, the current situation is maintained unchanged, and the timing and keeping warm module is triggered to start timing the duration of the substrate keeping warm until the duration of the substrate keeping warm reaches a preset time, thereby triggering the fifth temperature judgment submodule; otherwise, the second temperature judgment submodule is triggered; The second temperature judgment submodule can judge whether the current temperature of the substrate needs to be quickly cooled according to the temperature information fed back by the thermocouple temperature measuring element. If the judgment result shows that the current temperature of the substrate needs to be quickly cooled, a first execution instruction is sent to the airflow field monitoring-control unit to open the electromagnetic flow regulating valve, input the protective gas into the sealed protective cavity, and trigger the fourth temperature judgment submodule; otherwise, the third temperature judgment submodule is triggered; The third temperature judgment submodule can judge whether the current temperature of the substrate needs to be heated according to the temperature information fed back by the thermocouple temperature measuring element. If the judgment result shows that the current temperature of the substrate needs to be inductively heated, a second execution instruction is sent to the temperature field monitoring-control unit to turn on the induction coil heating and trigger the fourth temperature judgment submodule; otherwise, a third execution instruction is sent to the temperature field monitoring-control unit to turn off the induction coil and trigger the fourth temperature judgment submodule. The fourth temperature judgment submodule can judge whether the current temperature of the substrate reaches the second preset temperature range according to the temperature information fed back by the thermocouple temperature measuring element. If the judgment result shows that the current temperature of the substrate reaches the second preset temperature range, the fifth temperature judgment submodule is triggered; otherwise, the first temperature judgment submodule is triggered. The fifth temperature judgment submodule is used to judge whether the temperature information fed back by the infrared thermometer reaches the first preset temperature range. If the judgment result shows that the temperature information fed back by the infrared thermometer is within the first preset temperature range, the temperature field of the entire laser additive manufacturing process is controlled; otherwise, the first temperature judgment submodule is triggered.

2. The laser additive manufacturing system for in-situ adaptively controlling component shape through temperature field and airflow field according to claim 1, characterized in that: The thermocouple temperature measuring elements include several thermocouple temperature measuring elements, one of which is arranged at the middle position of the substrate, and the other thermocouple temperature measuring elements are evenly arranged around the substrate.

3. The laser additive manufacturing system for in-situ adaptively controlling component shape through temperature field and airflow field according to claim 1, characterized in that: It includes a laser directed energy deposition system, which includes a robotic arm, a laser, a powder feeder, a water cooler, and a laser additive manufacturing cladding head; One end of the laser additive manufacturing cladding head is connected to the power output end of the robot arm, and the other end extends into the sealed protection cavity and is sealedly connected to the sealed protection cavity; The laser additive manufacturing cladding head is provided with a powder feeding channel, a water cooling channel and a laser light channel; the laser light channel is connected to the laser through a laser transmission optical fiber; the water cooling channel is connected to the output end of the water cooler; and the powder feeding channel is connected to the output end of the powder feeder.

4. The laser additive manufacturing system for in-situ adaptively regulating component shape through temperature field and airflow field according to claim 3, characterized in that: The sealed protection cavity comprises a cover plate, a transparent high temperature resistant protective film, high temperature resistant gloves, an inspection window, a sealed protection cavity body and a fixing fixture for a cladding head, wherein: The sealing protection cavity body is placed on a working platform and clamped by a mechanical fixing fixture provided on the working platform; The high temperature resistant gloves and the inspection window are fixed to the pre-opened sealing protection cavity body through a sealing flange connection; The transparent high temperature resistant protective film is fixed on the main body of the sealed protective cavity; The cover plate is arranged above the transparent high temperature resistant protective film and is clamped with the sealed protective cavity body by means of a spring pre-tightening buckle; the infrared thermometer is installed on the cover plate close to the inspection window, and the detection head of the infrared thermometer can detect the temperature inside the sealed protective cavity through the inspection window.

5. The laser additive manufacturing system for in-situ adaptively regulating component shape through temperature field and airflow field according to claim 4, characterized in that: The transparent high-temperature resistant protective film is designed into a regular hexagon according to the movement requirements of the laser additive manufacturing cladding head, and is folded into a pyramid-shaped quadrangular pyramid during installation; the top of the transparent high-temperature resistant protective film is reserved with an opening that can just pass through the laser additive manufacturing cladding head, and is fixed to the laser additive manufacturing cladding head through a cladding head fixing fixture, the cladding head fixing fixture includes eight completely identical clamping bodies that are clamped in pairs, and adjacent clamping bodies are connected by bolts. At the same time, rubber sealing gaskets that just pass through the laser additive manufacturing cladding head are placed between adjacent clamping bodies. According to actual working requirements, a circular opening for passing a powder feeder pipeline and a water cooling pipeline is pre-opened on the surface of the cladding head fixing fixture.

6. The laser additive manufacturing system for in-situ adaptively regulating component shape through temperature field and airflow field according to claim 5, characterized in that: The thickness of the transparent high temperature resistant protective film is 0.3mm.

7. The laser additive manufacturing system for in-situ adaptively regulating component shape through temperature field and airflow field according to claim 5, characterized in that: A scraper is installed in the center of the inspection window, and the scraper is mechanically connected to a handle on the outside of the inspection window.

8. A laser additive manufacturing method for in-situ adaptively regulating the shape of a component by temperature field and airflow field, which is realized based on the laser additive manufacturing system for in-situ adaptively regulating the shape of a component by temperature field and airflow field according to claim 1, characterized in that: The steps include: Step 1: Turn on the airflow field monitoring-control unit to input protective gas into the sealed protective cavity to achieve deoxygenation operation of the sealed protective cavity; Step 2: Detect the oxygen content in the sealed protection cavity by an oxygen content detector until the oxygen content in the sealed protection cavity detected by the oxygen content detector reaches a safe range, close the electromagnetic flow regulating valve, and stop inputting protective gas into the sealed protection cavity; Step 3: Turn on the temperature field monitoring-control unit to adaptively control the temperature field of the entire laser additive manufacturing process in situ, which specifically includes the following steps: Step 3.1, judging whether the current temperature of the substrate needs to be kept warm according to the temperature information detected by the thermocouple temperature measuring element; when the judgment result shows that the current temperature of the substrate needs to be kept warm, the current state is maintained unchanged, and after the duration of the substrate warm state reaches a preset time, step 3.5 is entered; otherwise, step 3.2 is entered; Step 3.2, judging whether the current temperature of the substrate needs to be quickly cooled; when the judgment result shows that the current temperature of the substrate needs to be quickly cooled, turning on the airflow field monitoring-control unit, opening the electromagnetic flow regulating valve, so as to input the protective gas into the sealed protective cavity, and then entering step 3.4; otherwise, entering step 3.3; Step 3.3, judging whether the current temperature of the substrate needs to be heated; when the judgment result shows that the current temperature of the substrate needs to be heated, turning on the induction heating coil to induction heat the substrate, and then entering step 3.4; Otherwise, turn off the induction heating coil and go to step 3.4; Step 3.4, judging in real time whether the current temperature of the substrate reaches the program setting temperature; when the judgment result shows that the current temperature of the substrate reaches the program setting temperature, proceed to step 3.5, otherwise, return to step 3.1; Step 3.5, determining in real time whether the temperature in the sealed protection cavity has reached a preset temperature path end point; When the judgment result shows that the temperature in the sealed protection cavity reaches the preset temperature path end point, the temperature field control of the entire laser additive manufacturing process is terminated. Otherwise, return to step 3.1.

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