Laser additive manufacturing system and method for in-situ adaptive control of component geometry by temperature field and airflow field

Abstract

The application discloses a kind of by temperature field and airflow field in situ adaptive control component shape laser additive manufacturing system and method thereof.Laser additive manufacturing system includes sealed protective cavity, total control unit, temperature field monitoring-control unit and airflow field monitoring-control unit.Temperature field monitoring-control unit includes infrared thermometer, thermocouple temperature measuring element and induction heating coil;Airflow field monitoring-control unit includes protective gas pipeline, electromagnetic flow regulating valve, oxygen content monitor and vacuum air filter.Total control unit includes temperature field control module and airflow field control module.Total control unit carries out in situ adaptive control to the temperature field of laser additive manufacturing by temperature field control module, improves the distribution of temperature field in the whole process of additive manufacturing, reduces the molten pool temperature gradient in the process of laser additive manufacturing, improves forming defect, and improves material performance.

Description

TECHNICAL FIELD

[0001] The present application relates to a laser additive manufacturing system for in-situ adaptive regulation of component shape by temperature field and airflow field, and belongs to the field of additive manufacturing. BACKGROUND

[0002] Additive manufacturing is a manufacturing technology based on computer-aided design model data, which is realized by layer-by-layer accumulation of materials. Compared with traditional subtractive manufacturing, additive manufacturing is a "bottom-up" manufacturing technology, which can effectively shorten the product development cycle and has great application potential. It is developing rapidly. Metal component additive manufacturing is an important application direction in the field. In the process of additive manufacturing of metal components, the metal melt undergoes a repeated heating and cooling cycle under the action of the laser beam. Heat is continuously generated and diffused. Different shaped components will have different heat accumulation effects during forming, resulting in inconsistent internal properties, uneven microstructure, coarse microstructure and serious composition segregation, etc. The difficulty of microstructure performance regulation and local performance customized manufacturing of the component is increased. Specifically, before the additive manufacturing of the component starts, if the surface temperature of the substrate is too low, it is easy to cause defects in the forming of the formed part, affecting the processing index. After the additive manufacturing forming process is completed, the surface of the component still maintains a high temperature, and in the absence of protection, it is easy to be contaminated or oxidized by active ingredients in the surrounding environment. The existing technology has very limited effect on the control of the temperature of the component. Therefore, a temperature field control device for the component is needed, so that the temperature of the printing site of the formed part before being processed can meet the requirements, and after additive manufacturing printing, the surface temperature of the formed part can be maintained at a certain temperature, or gradually reduced in the form of a certain temperature step, to achieve the effect of heat treatment. SUMMARY

[0003] The purpose of the present application is to provide a laser additive manufacturing system for in-situ adaptive regulation of component shape by temperature field and airflow field. The system applies auxiliary heat field and airflow field from the process point of view based on the existing laser directional energy deposition technology, controls temperature change according to specific implementation requirements, thereby realizing the regulation of temperature field in the whole process of additive manufacturing, improving the distribution of temperature field in the whole process of additive manufacturing, reducing the molten pool temperature gradient in the process of laser additive manufacturing, improving forming defects, and improving material performance.

[0004] To achieve the above technical purpose, the present application will adopt the following technical scheme:

[0005] A laser additive manufacturing system for in-situ adaptive regulation of component shape by temperature field and airflow field, comprising a sealed protective cavity, a total 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 temperature detector, a thermocouple temperature detecting element and an induction heating coil; the infrared temperature detector is installed through a sealed protection cavity, is used for detecting the temperature in the sealed protection cavity and can transmit the detected temperature information to the total control unit; the thermocouple temperature detecting element is installed on the substrate, is used for detecting the temperature of the substrate and can transmit the detected temperature information to the total control unit; the induction heating coil is placed in the sealed protection cavity and surrounds the substrate;

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

[0008] The electromagnetic flow regulating valve is used for detecting the protective gas flow in the input protective gas pipeline, and can transmit the detected protective gas flow information to the total control unit;

[0009] The oxygen content monitor is used for detecting the oxygen content of the protective gas output by the protective gas pipeline, and can transmit the detected protective gas oxygen content information to the total control unit;

[0010] The total control unit comprises a temperature field control module and a gas flow field control module;

[0011] The gas flow field control module judges whether the oxygen content in the sealed protection cavity reaches the safety range according to the protective gas oxygen content information fed back by the oxygen content monitor; when the judgment result shows that the oxygen content in the sealed protection cavity reaches the safety range, the electromagnetic flow regulating valve is closed, and the temperature field control module is triggered;

[0012] The temperature field control module comprises five temperature judgment submodules, which are 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 preserved according to the temperature information fed back by the thermocouple temperature detecting element; if the judgment result shows that the current temperature of the substrate needs to be preserved, the present condition is maintained unchanged, and the timing preservation module is triggered to start timing the duration of the substrate preservation, until the duration of the substrate preservation reaches the preset time length, the fifth temperature judgment submodule is triggered; otherwise, the second temperature judgment submodule is triggered;

[0014] The second temperature judging submodule is capable of judging whether the current temperature of the substrate needs to be rapidly cooled according to the temperature information fed back by the thermocouple temperature measuring element, and if the judging result indicates that the current temperature of the substrate needs to be rapidly 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 judging submodule; otherwise, the third temperature judging submodule is triggered.

[0015] The third temperature judging submodule is capable of judging whether the current temperature of the substrate needs to be heated according to the temperature information fed back by the thermocouple temperature measuring element, and if the judging result indicates 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 start the inductive coil heating, and the fourth temperature judging submodule is triggered; otherwise, a third execution instruction is sent to the temperature field monitoring-control unit to close the inductive coil, and the fourth temperature judging submodule is triggered.

[0016] The fourth temperature judging submodule is capable of judging 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, and if the judging result indicates that the current temperature of the substrate reaches the second preset temperature range, the fifth temperature judging submodule is triggered; otherwise, the first temperature judging submodule is triggered.

[0017] The fifth temperature judging submodule is used for judging whether the temperature information fed back by the infrared temperature measuring instrument reaches the first preset temperature range, and if the judging result indicates that the temperature information fed back by the infrared temperature measuring instrument is in the first preset temperature range, the temperature field of the whole process of the laser additive manufacturing is ended; otherwise, the first temperature judging submodule is triggered.

[0018] Preferably, the thermocouple temperature measuring elements include a plurality of thermocouple temperature measuring elements, one of which is arranged at the middle position of the substrate, and the rest of the thermocouple temperature measuring elements are uniformly arranged around the substrate.

[0019] Preferably, the laser additive manufacturing cladding head is arranged in the sealed protective cavity.

[0020] One end of the laser additive manufacturing cladding head is connected with the power output end of the mechanical arm, and the other end is inserted into the sealed protective cavity and is in sealed connection with the sealed protective 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 with the laser through a laser transmission optical fiber; the water cooling channel is in communication with the output end of the water cooler; and the powder feeding channel is in communication with the output end of the powder feeder.

[0022] Preferably, the sealing protection cavity comprises a cover plate, a transparent high-temperature-resistant protective film, a high-temperature-resistant glove, a viewing window, a sealing protection cavity body and a clamping fixture for the cladding head, wherein:

[0023] The sealing protection cavity body is placed on the workbench and clamped by the mechanical clamping fixture arranged on the workbench;

[0024] The high-temperature-resistant glove and the viewing window are fixed on the sealing protection cavity body with a pre-opened opening through a sealing flange;

[0025] The transparent high-temperature-resistant protective film is fixed on the sealing protection cavity body;

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

[0027] The infrared temperature measuring instrument is installed on the cover plate close to the viewing window, and the detection head of the infrared temperature measuring instrument can detect the temperature in the sealing protection cavity through the viewing window.

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

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

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

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

[0032] Step one, turn on the airflow field monitoring and control unit to input protective gas into the sealing protection cavity to realize the oxygen removal operation of the sealing protection cavity;

[0033] Step two, detecting the oxygen content in the sealed protection cavity by the oxygen content detector until the oxygen content detected by the oxygen content detector reaches the safety range, closing the electromagnetic flow regulating valve and stopping the input of the protective gas into the sealed protection cavity;

[0034] Step three, opening the temperature field monitoring-control unit to adaptively regulate and control the temperature field of the whole process of laser additive manufacturing in situ, specifically including the following steps:

[0035] Step 3.1, judging whether the current temperature of the substrate needs to be preserved 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 preserved, the current state is maintained unchanged, and the timing preservation module is started to time the duration of the substrate preservation state, and then step 3.5 is entered; otherwise, step 3.2 is entered;

[0036] Step 3.2, judging whether the current temperature of the substrate needs to be rapidly cooled; when the judgment result shows that the current temperature of the substrate needs to be rapidly cooled, the gas flow field monitoring-control unit is opened, the electromagnetic flow regulating valve is opened to input the protective gas into the sealed protection cavity, and then step 3.4 is entered; otherwise, step 3.3 is entered;

[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 opened to inductively heat the substrate, and then step 3.4 is entered; otherwise, the induction heating coil is closed, and step 3.4 is entered;

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

[0039] Step 3.5, judging whether the temperature in the sealed protection cavity reaches the preset temperature path end point in real time; when the judgment result shows that the temperature in the sealed protection cavity reaches the preset temperature path end point, the temperature field regulation and control of the whole process of laser additive manufacturing is ended; otherwise, step 3.1 is returned to.

[0040] Based on the above technical purposes, compared with the prior art, the present application has the following advantages:

[0041] 1. The laser additive manufacturing system for in-situ adaptive regulation of component shape by temperature field can simultaneously monitor the temperature of the box and the forming material in real time through two means, realize the temperature field monitoring of the whole additive manufacturing process, and intuitively present the results to the system through the visual software, and the system will automatically adjust and control the substrate temperature to be stable within a limited range, without direct operation to realize adaptive temperature control, thereby reducing labor cost and reducing safety hazards.

[0042] 2. The laser additive manufacturing system for in-situ adaptive regulation of component shape by temperature field can quickly change the temperature of the substrate and the box according to the material forming needs, and realize the functions of preheating, heat preservation, heat treatment and rapid cooling of the substrate by planning the temperature change path in advance, so as to reduce the temperature difference between the printed component and the substrate, reduce the phenomena of uneven organization, coarse organization and composition segregation caused by too large temperature difference, avoid the material shape change caused by temperature field, and greatly improve the material forming quality, thereby providing a new idea for solving the material shape instability problem in laser directional energy deposition.

[0043] 3. The laser additive manufacturing system for in-situ adaptive regulation of component shape by temperature field can quickly cool the component through the flow field of cooling gas after the printing process is completed, so as to reduce the oxidation of the component in the 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 can reduce the oxygen concentration of the whole environment to a reasonable range in a short time, avoid the leakage of protective gas by customizing a sealing clamp, so that the device can effectively avoid the escape of protective gas, and the oxygen content is maintained at the same level for a long time. Compared with the chamber used in common laser directional energy deposition technology, the volume of the protective cavity is greatly reduced without hindering the movement of the mechanism, which greatly saves the material forming time and the amount of protective gas, and reduces the safety hazards. BRIEF DESCRIPTION OF DRAWINGS

[0045] Figure 1 It is the overall structure schematic diagram of the laser additive manufacturing system for in-situ adaptive regulation of component shape by temperature field and airflow field.

[0046] In the figure: 1, laser directional energy deposition system; 2, sealed protective cavity; 3, temperature field monitoring-control unit; 4, airflow field monitoring-control unit; 5, total control unit; 1.1, KUKA robot; 1.3, powder feeder; 1.5, laser additive manufacturing cladding head.

[0047] Figure 2 It is a schematic diagram of the installation mode of the laser additive manufacturing cladding head and the transparent heat-resistant film.

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

[0049] Figure 3 Schematic diagram of internal structure for 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, viewing window; 2.5, sealing protection cavity main body; 2.6, fixing clamp for cladding head; 3.1, infrared temperature measuring instrument; 3.3, induction heating coil; 4.1, protective gas pipeline; 4.2, electromagnetic flow regulating valve; 4.3, oxygen content monitor; 4.4, air filter; 5.1, substrate for laser additive manufacturing; 5.2, magnetic attraction fixing clamp;

[0051] Figure 4 Temperature field and temperature field control system program block diagram. DETAILED DESCRIPTION

[0052] The technical solutions in the embodiments of the present application will be described clearly and completely below in conjunction with the drawings in the embodiments of the present application. Obviously, the described embodiments are only part of the embodiments of the present application, rather than all the embodiments. The description of the at least one exemplary embodiment is actually only illustrative, but not as any limitation on the present application and its application or use. Based on the embodiments in the present application, all other embodiments obtained by those of ordinary skill in the art without making creative efforts fall within the scope of protection of the present application. Unless otherwise specified, the relative arrangement, expression and numerical value of the components and steps set forth in these embodiments do not limit the scope of the present application. The technology, method and equipment known to those of ordinary skill in the related art can not be discussed in detail, but should be regarded as part of the specification under appropriate circumstances. 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 exemplary embodiments can have different values.

[0053] For ease of description, spatial relative terms such as "above," "over," "on the upper surface of," "above," etc., are used here to describe the spatial positional relationship of a device or feature as shown in the figure with other devices or features. It should be understood that spatial relative terms are intended to encompass different orientations in use or operation besides the orientation of the device as described in the figure. For example, if the device in the figure is inverted, a device described as "above" or "above" other devices or structures would subsequently be positioned as "below" or "under" other devices or structures. Thus, the exemplary term "above" can include both "above" and "below." The device may 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 temperature field control of component shape according to the present invention includes: a laser directional energy deposition system, a sealed protective cavity, a temperature field monitoring and control unit, an airflow field monitoring and control unit, and a main control unit, wherein:

[0055] The laser-directed energy deposition system of the present invention includes 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 at 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 fiber. The high temperature of the laser melts the powder. The KUKA robot moves along a set path and deposits the molten metal powder layer by layer onto a special additive manufacturing substrate. The water-cooling mechanism provides cooling for the laser additive manufacturing cladding head to prevent overheating damage to the cladding head.

[0056] The sealed protective cavity is made of stainless steel, such as Figure 3As shown, the system comprises a sealed protective cavity body, a cover plate, a transparent high-temperature resistant protective film, high-temperature resistant gloves, an inspection window, a temperature field monitoring and control unit, and an airflow field monitoring and control unit. The sealed protective cavity body is made of stainless steel with openings on its surface for mounting other components. The high-temperature resistant gloves are fixed to the sealed protective cavity body via flanges, and their range of motion is greater than or equal to the length of the long side of the inner wall of the sealed protective cavity body. The inspection window is mounted and fixed to the sealed protective cavity body via flanges. The glass used in the inspection window is made of a special material to reduce interference with infrared light and improve the accuracy of the temperature measurement system. A scraper that can rotate along an axis is installed in the center of the inspection window to prevent smoke and dust generated during additive manufacturing from obstructing observation. The protective gas pipeline in the airflow field monitoring and control unit flows protective gas through pre-drilled holes in the sealed protective cavity body. The gas cylinder conducts gas to the sealed protective cavity body, and the protective gas pipeline is fixed to the sealed protective cavity body. The oxygen content monitor is suspended on the surface of the sealed protective cavity body and can be moved by hand as needed to observe changes in oxygen content. The thermocouple temperature measuring element in the temperature field monitoring and control unit, which monitors the substrate temperature, needs to be adjusted according to the substrate position and is fixed to the center and around the substrate by clamps. At the same time, the infrared detector that monitors the temperature of the sealed protective cavity is fixed in a key position in the cavity and does not need to be moved frequently. The induction heating unit is fixed inside the sealed protective cavity body and does not contact the surface of the sealed protective cavity body. The wires are connected to the main control unit through the reserved holes on the surface of the sealed protective cavity body.

[0057] Before use, the sealed protective cavity body should be assembled in a fixed sequence: First, use a level to calibrate the position of the sealed protective cavity body, and then use a mechanical positioning clamp to fix the sealed protective cavity body on the workbench; open the hatch, adjust the position of the magnetic clamp according to the size of the additive manufacturing substrate used, and leave appropriate space to prevent the substrate from deforming due to heat, making it difficult to remove; adjust the position of the thermocouple temperature sensing element, placing it in the center and around the lower surface of the additive manufacturing substrate, and adjust the position of the induction heating element to avoid contact with the substrate and reduce safety hazards; place the transparent high-temperature resistant protective film according to... Figure 2 Fold in the order shown. The high-temperature resistant protective film is fixed around the perimeter of the sealed protective cavity body with sealing tape. Install the top cover and close the surrounding metal pre-tightening buckles. The high-temperature resistant protective film has an opening at its center that perfectly accommodates the laser additive manufacturing cladding head. The opening is fixed to the laser additive manufacturing cladding head by a cladding head fixing clamp. The cladding head fixing clamp consists of eight identical clamping parts, with non-standard sealing gaskets between them that allow the laser additive manufacturing cladding head to pass through. Adjacent clamping parts are connected by bolts. The installation structure of the cladding head fixing clamp is as follows: Figure 2 As shown, finally, the powder feeding pipe and water cooling pipe are passed through the reserved holes on the surface of the cladding head fixing fixture; after adjusting the cladding head to the preset height and ensuring the correct installation sequence, the hatch is closed tightly.

[0058] The gas flow field monitoring-control unit comprises a protective gas pipeline, an electromagnetic flow regulating valve, an oxygen content detector and an air filter, after the current sequence processing is completed, the protective gas is manually started to remove oxygen, the oxygen content detector is located at the output end of the protective gas, when the oxygen removal is started, the oxygen content detector returns a signal to the total control system, if the oxygen content reaches a reasonable range, the electromagnetic flow regulating valve is automatically closed, the temperature adjusting link is started, and the oxygen content in the main body of the sealed protective cavity is automatically adjusted.

[0059] The control system comprises three parts of real-time feedback by a temperature sensor, self-determination of the system to output a control instruction and automatic opening and closing of mechanical elements according to the instruction, so as to realize adaptive regulation and control of the temperature field in the whole process of additive manufacturing printing according to the set temperature change path.

[0060] The temperature field monitoring-control unit is composed of an infrared temperature detector, a thermocouple temperature measuring element and an induction heating coil, the infrared temperature detector is located outside the viewing window, and the dust on the surface of the viewing window is scraped off by a scraper during observation to prevent interference with the observation results, the result of the infrared temperature detector is fed back to the total control system, and the visual software is directly reflected; the thermocouple temperature measuring elements located at the center and around the substrate feed back electric signals to the total control system, when the control system judges that the temperature needs to be heated, the induction heating element is started to quickly heat the components and the substrate, and the next temperature control step is performed after the monitoring reaches the set temperature; when the control system judges that the temperature needs to be quickly cooled, the gas flow field control unit is started, and the protective gas far lower than the temperature in the cavity is quickly introduced into the cavity for rapid cooling; when the control system judges that the temperature reaches the program set temperature value, the timing heat preservation module is entered, and the timing heat preservation function is realized according to the set temperature path; the temperature change path of the system only needs to start the set temperature change path, so that the temperature field in the whole process of additive manufacturing printing can be adaptively regulated and controlled, the formed components can be kept at a certain temperature for a long time, or gradually heated or cooled in the form of a certain temperature step, and the effects of preheating or heat treatment are realized.

[0061] Specifically, the total control unit comprises a temperature field control module and a gas flow field control module.

[0062] The gas flow field control module judges whether the oxygen content in the sealed protective cavity reaches a safe range according to the protective gas oxygen content information fed back by the oxygen content detector, when the judgment result shows that the oxygen content in the sealed protective cavity reaches the safe range, the electromagnetic flow regulating valve is closed, and the temperature field control module is triggered.

[0063] The temperature field control module comprises five temperature judgment sub-modules, which are the first to fifth temperature judgment sub-modules;

[0064] The first temperature judgment sub-module 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 status quo is maintained unchanged, and the timing keeping warm module is triggered to start timing the duration of keeping the substrate warm until the duration of keeping the substrate warm reaches the preset time length, and the fifth temperature judgment sub-module is triggered. Otherwise, the second temperature judgment sub-module is triggered.

[0065] The second temperature judgment sub-module can judge whether the current temperature of the substrate needs to be rapidly 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 rapidly cooled, a first execution instruction is sent to the airflow field monitoring-control unit to open the electromagnetic flow regulating valve to input protective gas into the sealed protection cavity, and the fourth temperature judgment sub-module is triggered. Otherwise, the third temperature judgment sub-module is triggered.

[0066] The third temperature judgment sub-module 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 start inductive coil heating, and the fourth temperature judgment sub-module is triggered. Otherwise, a third execution instruction is sent to the temperature field monitoring-control unit to close the inductive coil, and the fourth temperature judgment sub-module is triggered.

[0067] The fourth temperature judgment sub-module can judge whether the current temperature of the substrate reaches a 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 sub-module is triggered. Otherwise, the first temperature judgment sub-module is triggered.

[0068] The fifth temperature judgment sub-module is used to judge whether the temperature information fed back by the infrared temperature measuring instrument reaches a first preset temperature range. If the judgment result shows that the temperature information fed back by the infrared temperature measuring instrument is in the first preset temperature range, the temperature field of the whole process of laser additive manufacturing is ended. Otherwise, the first temperature judgment sub-module is triggered.

[0069] As shown in Figure 3 The present application discloses a laser additive manufacturing method for in-situ adaptive regulation and control of component morphology through temperature field and airflow field, comprising the following steps:

[0070] Step one, start the airflow field monitoring-control unit to input protective gas into the sealed protection cavity to realize the oxygen removal operation of the sealed protection cavity;

[0071] Step two, detecting the oxygen content in the sealed protection cavity by the oxygen content detector until the oxygen content detected by the oxygen content detector reaches the safety range, closing the electromagnetic flow regulating valve and stopping the input of the protective gas into the sealed protection cavity;

[0072] Step three, starting the temperature field monitoring-control unit to in-situ self-adaptively regulate and control the temperature field of the whole process of laser additive manufacturing, specifically including 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, a timing keeping warm module is started to time the duration of the keeping warm state of the substrate, and step 3.5 is entered; otherwise, step 3.2 is entered;

[0074] Step 3.2, judging whether the current temperature of the substrate needs to be rapidly cooled; when the judgment result shows that the current temperature of the substrate needs to be rapidly cooled, the gas flow field monitoring-control unit is started, the electromagnetic flow regulating valve is opened to input the protective gas into the sealed protection cavity, and then step 3.4 is entered; otherwise, step 3.3 is entered;

[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 started to inductively heat the substrate, and then step 3.4 is entered; otherwise, the induction heating coil is closed, and step 3.4 is entered;

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

[0077] Step 3.5, judging whether the temperature in the sealed protection cavity reaches the preset temperature path endpoint (the preset temperature path endpoint refers to the first preset temperature range) in real time; when the judgment result shows that the temperature in the sealed protection cavity reaches the preset temperature path endpoint, the regulation and control of the temperature field of the whole process of laser additive manufacturing is ended; otherwise, step 3.1 is returned to.

[0078] Any modification, equivalent replacement, improvement, etc. made within the spirit and principles of the present application is included in the protection scope of the present application.

Claims

1. A laser additive manufacturing system for in-situ adaptive regulation of component geometry by temperature field and gas flow field, comprising a sealed protective cavity and a general control unit, characterized in that, Further comprising a temperature field monitoring-control unit and a gas flow field monitoring-control unit; wherein: The temperature field monitoring-control unit comprises an infrared temperature detector, a thermocouple temperature detecting element and an induction heating coil; the infrared temperature detector is installed through a sealed protection cavity, used for detecting the temperature in the sealed protection cavity and capable of transmitting the detected temperature information to the total control unit; the thermocouple temperature detecting element is installed on the substrate, used for detecting the temperature of the substrate and capable of transmitting the detected temperature information to the total control unit; the induction heating coil is placed in the sealed protection cavity and arranged around the substrate; The gas flow field monitoring-control unit comprises 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 the sealed protection cavity, and the protective gas pipeline is provided with an external air inlet interface and an external air outlet interface through the sealed protection cavity; the external air inlet interface is connected with the air outlet of the protective gas cylinder through a protective gas output pipeline, and the electromagnetic flow regulating valve is installed on the external air inlet interface; the external air outlet interface is connected with the air inlet of the protective gas cylinder through a protective gas recovery pipeline, and the vacuum air filter and the oxygen content monitor are installed on the external air outlet interface in sequence according to the gas flow direction; The electromagnetic flow regulating valve is used for detecting the protective gas flow in the input protective gas pipeline, and capable of transmitting the detected protective gas flow information to the total control unit; The oxygen content monitor is used for detecting the oxygen content of the protective gas output by the protective gas pipeline, and capable of transmitting the detected protective gas oxygen content information to the total control unit; The total control unit comprises a temperature field control module and a gas flow field control module; The gas flow field control module judges whether the oxygen content in the sealed protection cavity reaches the safety range according to the protective gas oxygen content information fed back by the oxygen content monitor; when the judgment result shows that the oxygen content in the sealed protection cavity reaches the safety range, the electromagnetic flow regulating valve is closed, and the temperature field control module is triggered; The temperature field control module comprises five temperature judgment sub-modules, which are the first to fifth temperature judgment sub-modules; The first temperature judgment sub-module 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 detecting element; if the judgment result shows that the current temperature of the substrate needs to be kept warm, the present condition is maintained unchanged, and the timing keeping warm module is triggered to start timing the duration of the substrate keeping warm, until the duration of the substrate keeping warm reaches the preset time length, the fifth temperature judgment sub-module is triggered; otherwise, the second temperature judgment sub-module is triggered; The second temperature judgment sub-module can judge whether the current temperature of the substrate needs to be rapidly cooled according to the temperature information fed back by the thermocouple temperature detecting element; if the judgment result shows that the current temperature of the substrate needs to be rapidly cooled, the first execution instruction is sent to the gas flow field monitoring-control unit to open the electromagnetic flow regulating valve to input the protective gas into the sealed protection cavity, and the fourth temperature judgment sub-module is triggered; otherwise, the third temperature judgment sub-module is triggered; The third temperature judgment sub-module can judge whether the current temperature of the substrate needs to be slowly cooled according to the temperature information fed back by the thermocouple temperature detecting element; if the judgment result shows that the current temperature of the substrate needs to be slowly cooled, the second execution instruction is sent to the gas flow field monitoring-control unit to close the electromagnetic flow regulating valve to stop the input of the protective gas into the sealed protection cavity, and the fifth temperature judgment sub-module is triggered; otherwise, the fourth temperature judgment sub-module is triggered; The fourth temperature judgment sub-module 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 detecting element; if the judgment result shows that the current temperature of the substrate needs to be kept warm, the third execution instruction is sent to the gas flow field monitoring-control unit to open the electromagnetic flow regulating valve to input the protective gas into the sealed protection cavity, and the fifth temperature judgment sub-module is triggered; otherwise, the fifth temperature judgment sub-module is triggered; The fifth temperature judgment sub-module can judge whether the current temperature of the substrate needs to be rapidly cooled according to the temperature information fed back by the thermocouple temperature detecting element; if the judgment result shows that the current temperature of the substrate needs to be rapidly cooled, the fourth execution instruction is sent to the gas flow field monitoring-control unit to open the electromagnetic flow regulating valve to input the protective gas into the sealed protection cavity, and the first temperature judgment sub-module is triggered; otherwise, the first temperature judgment sub-module is triggered. The third temperature judging 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, and 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 start the inductive coil heating and trigger the fourth temperature judging submodule; otherwise, a third execution instruction is sent to the temperature field monitoring-control unit to close the inductive coil and trigger the fourth temperature judging submodule. The fourth temperature judging 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, and if the judgment result shows that the current temperature of the substrate reaches the second preset temperature range, the fifth temperature judging submodule is triggered; otherwise, the first temperature judging submodule is triggered. The fifth temperature judging submodule is used to judge whether the temperature information fed back by the infrared temperature measuring instrument reaches the first preset temperature range, and if the judgment result shows that the temperature information fed back by the infrared temperature measuring instrument is in the first preset temperature range, the temperature field of the whole process of the laser additive manufacturing is ended; otherwise, the first temperature judging submodule is triggered.

2. The laser additive manufacturing system for in-situ adaptive tuning of the geometry of the build by the temperature field and the gas flow field according to claim 1, wherein, The thermocouple temperature measuring elements include a plurality of thermocouple temperature measuring elements, one of which is arranged at the middle position of the substrate, and the rest of the thermocouple temperature measuring elements are uniformly arranged around the substrate.

3. The laser additive manufacturing system for in-situ adaptive tuning of the geometry of the build by the temperature field and the gas flow field according to claim 1, wherein, The laser directed energy deposition system includes a mechanical 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 with the power output end of the mechanical arm, and the other end extends into the sealed protection cavity and is sealingly connected with 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 with the laser through a laser transmission optical fiber; the water cooling channel is in communication with the output end of the water cooler; and the powder feeding channel is in communication with the output end of the powder feeder.

4. The laser additive manufacturing system for in-situ adaptive tuning of the geometry of the build by the temperature field and the gas flow field according to claim 3, wherein, The sealed protection cavity includes a cover plate, a transparent high-temperature-resistant protective film, a high-temperature-resistant glove, a viewing window, a sealed protection cavity body and a cladding head fixing clamp, wherein: The sealed protection cavity body is placed on the working platform and clamped by the mechanical fixing clamp arranged on the working platform; The high-temperature-resistant glove and the viewing window are fixed on the sealed protection cavity body with a pre-opening through a sealing flange; The transparent high-temperature-resistant protective film is fixed on the sealed protection cavity body; The cover plate is arranged above the transparent high-temperature-resistant protective film and clamped by the spring pre-tightening buckle and the sealed protection cavity body; the infrared temperature measuring instrument is installed on the cover plate close to the viewing window, and the detection head of the infrared temperature measuring instrument can detect the temperature in the sealed protection cavity through the viewing window.

5. The laser additive manufacturing system for in-situ adaptive tuning of the geometry of the build by the temperature field and the gas flow field according to claim 4, wherein, The transparent high-temperature-resistant protective film is designed into a regular hexagon according to the movement requirement of a laser additive manufacturing cladding head, and is folded into a pyramid-shaped quadrangular pyramid when installed; the top end of the transparent high-temperature-resistant protective film is reserved with an opening just capable of passing through the laser additive manufacturing cladding head, and is fixed on the laser additive manufacturing cladding head through a cladding head fixing clamp; the cladding head fixing clamp comprises eight identical clamping bodies which are arranged in pairs to form a pair of clamping bodies, the adjacent clamping bodies are connected through bolts, and a rubber sealing gasket just capable of passing through the laser additive manufacturing cladding head is arranged between the adjacent clamping bodies; and a circular opening for passing through a powder feeder pipeline and a water cooling pipeline is pre-opened on the surface of the cladding head fixing clamp according to actual working requirements.

6. The laser additive manufacturing system for in-situ adaptive tuning of the geometry of the build by the temperature field and the gas flow field according to claim 5, wherein, The thickness of the transparent high-temperature-resistant protective film is 0.3 mm.

7. The laser additive manufacturing system for in-situ adaptive tuning of the geometry of the build by the temperature field and the gas flow field according to claim 5, wherein, A scraper is installed at the center of the inspection window, and the scraper is mechanically connected to the handle outside the inspection window.

8. A laser additive manufacturing method for in-situ adaptive control of component geometry by temperature field and gas flow field, based on the laser additive manufacturing system for in-situ adaptive control of component geometry by temperature field and gas flow field according to claim 1, characterized in that, The method comprises the following steps: Step 1, turn on the airflow field monitoring and control unit to input protective gas into the sealed protective cavity to realize oxygen removal operation of the sealed protective cavity; Step 2, detect the oxygen content in the sealed protective cavity through an oxygen content detector until the oxygen content in the sealed protective cavity detected by the oxygen content detector reaches a safe range, then close the electromagnetic flow regulating valve to stop inputting protective gas into the sealed protective cavity; Step 3, turn on the temperature field monitoring and control unit to adaptively regulate the temperature field of the whole laser additive manufacturing process in situ, which comprises the following steps: Step 3.1, according to the temperature information detected by the thermocouple temperature measuring element, determine whether the current temperature of the substrate needs to be kept; when the determination result shows that the current temperature of the substrate needs to be kept, the current state is maintained unchanged, and after the duration of the substrate keeping state reaches the preset time length, step 3.5 is entered; otherwise, step 3.2 is entered; Step 3.2, determine whether the current temperature of the substrate needs to be rapidly cooled; when the determination result shows that the current temperature of the substrate needs to be rapidly cooled, turn on the airflow field monitoring and control unit to open the electromagnetic flow regulating valve to input protective gas into the sealed protective cavity, and then enter step 3.4; otherwise, enter step 3.3; Step 3.3, determine whether the current temperature of the substrate needs to be heated; when the determination result shows that the current temperature of the substrate needs to be heated, turn on the induction heating coil to heat the substrate, and then enter step 3.4; otherwise, turn off the induction heating coil and enter step 3.4; Step 3.4, determine whether the current temperature of the substrate reaches the program set temperature in real time; when the determination result shows that the current temperature of the substrate reaches the program set temperature, enter step 3.5; otherwise, return to step 3.1; Step 3.5, determine whether the temperature in the sealed protective cavity reaches the preset temperature path endpoint in real time; When the determination result shows that the temperature in the sealed protective cavity reaches the preset temperature path endpoint, the temperature field regulation of the whole laser additive manufacturing process is ended; otherwise, return to step 3.

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