Detection control method for high uniformity of oriented energy deposition layer

Abstract

The invention relates to a detection control method for high uniformity of a directional energy deposition layer. By executing the method for detecting and controlling the uniformity of the directional energy deposition layer, the area of a molten pool and the working power of a laser are accurately controlled in the printing process of the deposition layer, and the height of each deposition layer is accurately controlled by accurately controlling the area of the molten pool in the printing process of the deposition layer; the layer height consistency and uniformity of all the deposition layers are accurately controlled in the deposition printing process, so that the problems of unstable layer height and uneven surface of the deposition layers are solved, the probability of part defects and performance problems caused by layer height inconsistency and overlarge errors is reduced, and the production efficiency is improved. Therefore, the subsequent machining allowance and the rejection rate are reduced, the probability of manual correction intervention on the height of the deposition layer in the whole deposition printing process is reduced, and the deposition printing efficiency is improved.

Description

Technical Field

[0001] The present invention relates to the technical field of laser processing, and particularly to a method for detecting and controlling the uniformity of a directed energy deposition layer. Background Art

[0002] As an advanced manufacturing technology, the laser directed energy deposition additive manufacturing technology has the advantages of flexible material feeding mode, high forming efficiency and freedom, strong feasibility of multi-process combination, etc. It can solve the problems of high-efficiency, high-performance and high-precision manufacturing of large integral components, multi-material integration, complex curved surfaces, etc., and has been widely used in the fields of aerospace, automotive rail transit, energy and power, etc.

[0003] Currently, the existing technologies all collect the temperature at the center of the molten pool and the size of the molten pool, fit and establish the functional relationship between the temperature and size of the molten pool and the laser power, material feeding speed and scanning speed, and then control the height defect of the printed layer to improve the printing quality. However, this method of controlling the height defect of the printed layer by collecting the temperature at the center of the molten pool and the size of the molten pool and fitting and establishing the functional relationship of various printing parameters has the following problems: During the printing and deposition manufacturing process of metal parts, due to the influence of various factors, such as powder characteristics, wire characteristics (such as slight differences in wire diameter, tension fluctuations during wire feeding, non-uniformity of wire melting, changes in metal cooling and solidification conditions, stability of laser energy input, molten pool dynamics, and matching of acceleration and deceleration changes of the motion system with input energy), etc., the complexity of the influence makes it difficult for the printing system to accurately control the deposition printing height uniformity of each layer, and the height of a single deposition layer will show a wavy change. And a large height difference in the deposition layer will affect the dimensional accuracy, surface quality and internal structure integrity of the part. As the height error of the deposition layer accumulates too much, it will directly cause changes in the laser energy focus and the molten pool, resulting in changes in the positional relationship between the powder or wire and the laser energy beam, thus making the printing and deposition process unable to continue. Summary of the Invention

[0004] Based on this, it is necessary to provide a method for detecting and controlling the height uniformity of a directed energy deposition layer, which can accurately control the height uniformity of the deposition layer to improve the product accuracy and product quality of the deposition printing.

[0005] A method for detecting and controlling the height uniformity of a directed energy deposition layer includes the steps of: Providing a laser deposition printing system; the deposition printing system includes a molten pool visual monitoring device, an optical ranging device, a directed energy deposition printing head and a printing head driving mechanism; both the molten pool visual monitoring device and the optical ranging device are installed on the directed energy deposition printing head; Before starting to print the deposition layer of the current layer, use the optical ranging device to collect the distance between the deposition layer of the previous layer and the signal receiving end of the optical ranging device to obtain the deposition layer height before printing; Use the print head driving mechanism to drive the directed energy deposition print head to perform deposition printing on the deposition layer of the previous layer, and use the molten pool vision monitoring device to collect the molten pool area within a preset time period before the collection time point to obtain the standard molten pool area; Record the printing position corresponding to the collection time point to obtain the break point position; Use the print head driving mechanism to drive the directed energy deposition print head to continue deposition printing starting from the break point position, and use the molten pool vision monitoring device to collect the molten pool area in real time at a preset frequency to obtain the current molten pool area; While continuing deposition printing starting from the break point position, according to the standard molten pool area and the current molten pool area, perform real-time regulation on the working power of the laser that provides the printing laser beam for the directed energy deposition print head to stabilize the current molten pool area within a preset area range; Use the optical ranging device to collect the distance between the deposition layer of the current layer and the signal receiving end of the optical ranging device to obtain the current deposition layer height; Calculate the difference between the current deposition layer height and the deposition layer height before printing to obtain the actual layer height of the deposition layer of the current layer; When the average value of the actual layer height of the deposition layer of the current layer is greater than the preset layer height value, use the print head driving mechanism to drive the directed energy deposition print head to remelt the position on the deposition layer where the actual layer height is greater than the preset layer height value until the average value of the actual layer height of the remelted part is less than or equal to the preset layer height value; When the average value of the actual layer height of the deposition layer of the current layer is less than or equal to the preset layer height value, return to execute the step of obtaining the deposition layer height before printing to print the deposition layer of the next layer.

[0006] The above-mentioned method for detecting and controlling high uniformity of directional energy deposition layer, during the printing process of each deposition layer, first obtains the standard molten pool area, then synchronously and real-time obtains the current molten pool area during the deposition printing process, and adjusts the working power of the laser in real-time according to the comparison result between the standard molten pool area and the current molten pool area, so as to stabilize the current molten pool area within the preset area range during the deposition printing process, and realizes the adaptive control of the molten pool area and the working power of the laser during the deposition layer printing process; obtains the actual layer height of the current deposition layer through the detected height of the deposition layer before printing (i.e., the height of the previous deposition layer) and the height of the current deposition layer, and thins the part of the current deposition layer with an actual layer height greater than the preset layer height value to an actual layer height less than or equal to the preset layer height value through the way of remelting processing, so as to realize the precise control of the layer height of each deposition layer. The implementation process of the above-mentioned method for detecting and controlling high uniformity of directional energy deposition layer has been completely automated, without the need for manual intervention and correction of the deposition layer height, molten pool area and the working power of the laser, reducing the risk of human intervention.

[0007] Therefore, the above-mentioned method for detecting and controlling high uniformity of directional energy deposition layer, through the precise control of the molten pool area and the working power of the laser during the deposition layer printing process, realizes the precise control of the layer height of each deposition layer through the precise control of the molten pool area during the deposition layer printing process, and through the precise control of the layer height consistency and uniformity of all deposition layers during the deposition printing process, solves the problems of unstable deposition layer height and uneven surface, reduces the probability of part defects and performance problems caused by inconsistent layer height and excessive error, thereby reducing the subsequent machining allowance and scrap rate, and reducing the probability of manual correction and intervention of the deposition layer height during the entire deposition printing process, improving the deposition printing efficiency. BRIEF DESCRIPTION OF THE DRAWINGS

[0008] Figure 1 It is a schematic flow chart of the method for detecting and controlling high uniformity of directional energy deposition layer in a preferred embodiment of the present invention; Figure 2 is Figure 1 a schematic structural diagram of the laser deposition printing system provided in step S10 in the method for detecting and controlling high uniformity of directional energy deposition layer shown; Figure 3 is Figure 1 a schematic flow chart of step S30 in the method for detecting and controlling high uniformity of directional energy deposition layer shown; Figure 4 is Figure 1 a schematic diagram of the molten pool pattern involved in step S33 in the method for detecting and controlling high uniformity of directional energy deposition layer shown; Figure 5 is Figure 1Flow chart of step S50 in the method for detecting and controlling high uniformity of the shown directed energy deposition layer; Figure 6 is Figure 1 Schematic diagram of the molten pool pattern involved in step S53 in the method for detecting and controlling high uniformity of the shown directed energy deposition layer; Figure 7 is Figure 1 Flow chart of step S60 in the method for detecting and controlling high uniformity of the shown directed energy deposition layer; Figure 8 is Figure 1 Flow chart of step S80 in the method for detecting and controlling high uniformity of the shown directed energy deposition layer; Figure 9 is Figure 1 Flow chart of step S90 in the method for detecting and controlling high uniformity of the shown directed energy deposition layer.

[0009] Explanation of the reference numerals in the drawings in the specific implementation manners: 100, laser deposition printing system; 110, molten pool vision monitoring device; 120, optical ranging device; 130, directed energy deposition print head; 140, print head driving mechanism; 160, workbench; 170, loading device; 180, computer control system. Specific implementation manners

[0010] For the convenience of understanding the present invention, the present invention will be described more comprehensively below with reference to the relevant drawings. Preferred embodiments of the present invention are shown in the drawings. However, the present invention can be implemented in many different forms and is not limited to the embodiments described herein. On the contrary, these embodiments are provided to make the understanding of the disclosure of the present invention more thorough and comprehensive.

[0011] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by those skilled in the technical field to which the present invention belongs. The terms used in the description of the present invention in this specification are only for the purpose of describing specific embodiments and are not intended to limit the present invention. The term "and / or" used herein includes any and all combinations of one or more of the related listed items.

[0012] When describing the positional relationship, unless otherwise specified, when an element is referred to as being "on" another element, it can be directly on the other element or there can also be an intermediate element. It can also be understood that when an element is referred to as being "between" two elements, it can be the only one between the two elements or there can also be one or more intermediate elements.

[0013] In the case of using "comprising", "having", and "including" described in this text, unless explicit limiting terms are used, such as "only", "consisting of", etc., another component can also be added. Unless otherwise mentioned, terms in the singular form can include the plural form and should not be understood as having a quantity of one.

[0014] Please refer to Figure 1 , the method for detecting and controlling the height of the directed energy deposition layer in the preferred embodiment of the present invention includes steps S10 to S100.

[0015] Please also refer to Figure 2 , step S10, provide a laser deposition printing system 100. The deposition printing system includes a molten pool vision monitoring device 110, an optical ranging device 120, a directed energy deposition print head 130, and a print head driving mechanism 140. The molten pool vision monitoring device 110 and the optical ranging device 120 are both installed on the directed energy deposition print head 130. The directed energy deposition print head 130 is used to emit a printing laser beam emitted by a laser to a workbench 160.

[0016] In order to ensure the measurement accuracy of the optical ranging device 120, specifically in one embodiment, the detection laser beam emitted by the optical ranging device 120 is perpendicular to the surface of the deposition layer or the workbench 160 in the laser deposition printing system 100.

[0017] Of course, in other embodiments, the detection laser beam emitted by the optical ranging device 120 can also be obliquely incident on the deposition layer or the surface of the workbench 160.

[0018] Step S20, before starting to print the deposition layer of the current layer, use the optical ranging device 120 to collect the distance between the deposition layer of the previous layer and the signal receiving end of the optical ranging device 120 to obtain the height of the deposition layer before printing.

[0019] Specifically, before starting to print the deposition layer of the current layer, use the optical ranging device 120 to collect the distance between the surface of the workbench 160 in the laser deposition printing system 100 and the signal receiving end of the optical ranging device 120 to obtain the height of the deposition layer before printing.

[0020] Step S30, use the print head driving mechanism 140 to drive the directed energy deposition print head 130 to perform deposition printing on the deposition layer of the previous layer, and use the molten pool vision monitoring device 110 to collect the molten pool area within a preset time period before the collection time point to obtain the standard molten pool area.

[0021] Specifically, within a preset time period before the acquisition time point, the molten pool vision monitoring device 110 can obtain multiple sets of detection data, and by calculating the mean of the multiple sets of detection data, the standard molten pool area can be obtained.

[0022] When performing step S30, if the deposited layer of the current layer is the first deposited layer, the print head driving mechanism 140 is used to drive the directed energy deposition print head 130 to perform deposition printing on the tabletop of the workbench 160, and the molten pool vision monitoring device 110 is used to collect the molten pool area within a preset time period before the acquisition time point to obtain the standard molten pool area.

[0023] Step S40, record the printing position corresponding to the acquisition time point to obtain the break point position.

[0024] Among them, the printing position is the position where the printing laser beam emitted by the directed energy deposition print head 130 irradiates on the deposited layer at the acquisition time point, and the printing work of the deposited layer is briefly interrupted here to provide time for data processing of the collected data. By performing step S40, the position coordinates of the break point position are recorded.

[0025] Step S50, use the print head driving mechanism 140 to drive the directed energy deposition print head 130 to continue deposition printing starting from the break point position, and use the molten pool vision monitoring device 110 to collect the molten pool area in real time at a preset frequency to obtain the current molten pool area.

[0026] Step S60, while performing step S50, according to the standard molten pool area and the current molten pool area, the working power of the laser that provides the printing laser beam for the directed energy deposition print head 130 is adjusted in real time to stabilize the current molten pool area within a preset area range.

[0027] Step S70, use the optical ranging device 120 to collect the distance between the deposited layer of the current layer and the signal receiving end of the optical ranging device 120 to obtain the current deposited layer height.

[0028] It should be noted that the current deposited layer height is actually the distance height of the deposited layer of the current layer relative to the signal receiving end of the optical ranging device. Of course, in some other embodiments, the current deposited layer height can also be understood as the actual height of the deposited layer of the current layer with reference to the tabletop of the workbench, and this actual height is obtained by converting the distance between the deposited layer of the current layer and the signal receiving end of the optical ranging device.

[0029] Step S80, calculate the difference between the current deposited layer height and the deposited layer height before printing to obtain the actual layer height of the deposited layer of the current layer.

[0030] Step S90, when the average value of the actual layer height of the current layer deposition layer is greater than the preset layer height value, use the print head driving mechanism 140 to drive the directed energy deposition print head 130 to remelt the positions on the deposition layer where the actual layer height is greater than the preset layer height value until the average value of the actual layer height of the remelted part is less than or equal to the preset layer height value.

[0031] Step S100, when the average value of the actual layer height of the current layer deposition layer is less than or equal to the preset layer height value, return to repeat steps S20 to S90 to print the next layer of the deposition layer until the precision manufacturing part is obtained by layer-by-layer printing.

[0032] It should be noted that during the remelting process, the feeding device 170 is controlled to stop working to stop transporting metal powder or metal wire to the workbench 160. At the same time, the print head driving mechanism 140 drives the directed energy deposition print head 130 to perform laser scanning on the parts of the current layer deposition layer where the actual layer height is greater than the preset layer height value to thin the parts with too high layer height on the upper layer of the current layer deposition layer.

[0033] It should also be noted that all data processing in steps S20 to S100 and the automatic operation of each part in the laser deposition printing system 100 are respectively realized by the data processing module and the control module in the computer control system 180.

[0034] By executing steps S30 to S60, a standard molten pool area that can be used as a reference value is obtained in the early stage of printing the current layer deposition layer. The current molten pool area is obtained in real time in the middle and late stages of printing the current layer deposition layer, and these current molten pool areas are compared with the standard molten pool area. Then, the working power of the laser is adjusted in real time according to the comparison result to ensure that the current molten pool area can be stabilized within the preset area range, so as to realize the adaptive adjustment of the molten pool area and the working power of the laser during the deposition layer printing process.

[0035] During the printing process of each layer of the deposition layer, stabilizing the molten pool area within the preset area range can avoid problems such as poor surface quality of the deposition layer and easy generation of wavy surfaces due to too large a molten pool area, and can also avoid problems such as incomplete fusion of metal powder or metal wire due to too small a molten pool area, which may lead to the generation of pores and incomplete melting areas inside the part, effectively improving the surface quality of the deposition layer and the product quality of the deposited printing parts. Moreover, through the real-time adjustment of the working power of the laser, not only can the molten pool area be stabilized, but also the layer height of the deposition layer can be stabilized within a specific layer height range.

[0036] By performing step S20, step S70 to step S100, first obtaining the height of the deposition layer before printing (i.e., the height of the deposition layer of the previous layer) before printing the deposition layer, obtaining the height of the current deposition layer after the current deposition layer printing is completed, and calculating the actual layer height of the current layer deposition layer through the height of the deposition layer before printing and the height of the current deposition layer, and thinning the part of the current layer deposition layer with an actual layer height greater than the preset layer height value to an actual layer height less than or equal to the preset layer height value by means of remelting processing, so as to achieve precise control of the layer height of each deposition layer.

[0037] During the execution of step S10 to step S100, the optical ranging device 120, the molten pool vision monitoring device 110 and the print head driving mechanism 140 cooperate with each other to realize the full automation of the entire execution process of the above-mentioned detection and control method for the height uniformity of directional energy deposition. The whole process does not require manual intervention and correction of the deposition layer height, the molten pool area and the working power of the laser, reducing the risk of human intervention.

[0038] Therefore, the above-mentioned detection and control method for the height uniformity of directional energy deposition, through precise control of the molten pool area and the working power of the laser during the deposition layer printing process, realizes precise control of the layer height of each deposition layer through precise control of the molten pool area during the deposition layer printing process, and through precise control of the layer height consistency and uniformity of all deposition layers during the deposition printing process, solves the problems of unstable deposition layer height and uneven surface, reduces the probability of part defects and performance problems caused by inconsistent layer height and excessive error, thereby reducing the subsequent machining allowance and scrap rate, and reducing the probability of manual correction and intervention of the deposition layer height during the whole deposition printing process, improving the deposition printing efficiency.

[0039] In some embodiments, the sampling time interval of the optical ranging device 120 is . Among them, is the minimum linear distance in the scanning path, is the scanning speed of the laser deposition printing system 100.

[0040] The total time taken for the laser deposition printing system 100 to print a deposition layer is . Among them, is the total path length of the directional energy deposition print head 130 to print a deposition layer.

[0041] The number of sampling times of the optical ranging device 120 on a deposition layer is: .

[0042] Thus, the data acquisition frequency of the optical ranging device 120 is Periodic data acquisition can be performed. Given the scanning speed of the known laser deposition printing system 100, the minimum linear distance of the scanning path corresponding to each deposition layer, and the total length of the scanning path corresponding to each deposition layer, it is very easy to obtain the acquisition time interval of the optical ranging device 120 and the number of acquisitions required to complete one deposition layer, facilitating the recording of the acquisition data for each deposition layer and subsequent calculations.

[0043] Therefore, when performing step S20, the optical ranging device 120 acquires the distance between the deposition layer of the previous layer and the signal receiving end of the optical ranging device 120 to obtain multiple acquisition data, and obtains the height of the deposition layer before printing based on the multiple acquisition data. Similarly, when performing step S70, the optical ranging device 120 also obtains multiple acquisition data through periodic data acquisition, and then obtains the height of the current deposition layer based on these acquisition data to improve the measurement accuracy of the deposition layer height.

[0044] In some embodiments, the optical ranging device 120 is configured such that the laser beam emitted by it is perpendicularly incident on the deposition layer or the surface of the workbench 160 to ensure the accuracy of the measurement data of the optical ranging device 120.

[0045] Please refer to Figure 3 simultaneously. In some embodiments, step S30 includes steps S31 to S34.

[0046] Step S31, using the print head driving mechanism 140 to drive the directed energy deposition print head 130 to perform deposition printing on the deposition layer of the previous layer.

[0047] Of course, when the deposition layer of the current layer is the first deposition layer during the deposition printing process, when performing step S31, the directed energy deposition print head 130 performs deposition printing on the surface of the workbench 160.

[0048] Step S32, while performing step S31, using the molten pool vision monitoring device 110 to acquire the area of the molten pool within a preset time period before the acquisition time point to obtain a set of area image data.

[0049] Please refer to Figure 4 simultaneously. Step S33, extracting data features from the area image data and calculating the molten pool area in the th area image data according to the formula . Among them, is the longest side of the molten pool image in the th area image data, The shortest side of the molten pool image in the area image data.

[0050] By performing step S33, data feature extraction is carried out on the area image data, so as to obtain the longest side and the shortest side of the molten pool image in each area image data, and according to the area calculation formula of the approximate ellipse, the area of the molten pool image is calculated by using the longest side and the shortest side of the molten pool image.

[0051] Step S34, according to the formula For The molten pool areas of the sampling points Perform a mean calculation to obtain the standard molten pool area .

[0052] By performing steps S31 to S33, obtain In the preset time period before the sampling time point Zhang area image data, and calculate the molten pool area corresponding to each area image data according to the area calculation formula of the approximate ellipse. By performing step S34, perform a mean calculation on the

[0053] Please refer to Figure 5 together. In some embodiments, step S50 includes steps S51 to S53.

[0054] Step S51, use the print head driving mechanism 140 to drive the directed energy deposition print head 130 to continue deposition printing starting from the breakpoint position.

[0055] Step S52, while performing step S51, use the molten pool vision monitoring device 110 to collect the molten pool area to obtain the current area image.

[0056] Please refer to Figure 6 together. Step S53, perform data feature extraction on the current area image, and calculate the current molten pool area according to the following formula : .

[0057] Wherein, Is the longest side of the molten pool image in the current area image, Is the shortest side of the molten pool image in the current area image.

[0058] By performing step S51, the printing of the deposition layer starts from the breakpoint position, which can avoid repeated laser scanning or the situation where metal powder or wire is not melted, and further ensure the printing quality of the deposition printing. By performing steps S52 and S53, image acquisition, extraction of data features of the acquired images, and calculation of the data of the extracted features are realized to obtain the current molten pool area. Therefore, by performing steps S51 to S53, the real-time acquisition of the current molten pool area is realized on the premise of ensuring the printing quality of the deposition layer.

[0059] Please refer to Figure 7 together. In some embodiments, step S60 includes steps S61 to S63.

[0060] Step S61, compare the current molten pool area with the standard molten pool area.

[0061] Step S62, if the current molten pool area is smaller than the standard molten pool area, increase the working power of the laser that provides the printing laser beam for the directed energy deposition print head 130 until the current molten pool area is adjusted in real time to within the preset area range.

[0062] Step S63, if the current molten pool area is larger than the standard molten pool area, reduce the working power of the laser that provides the laser beam for the directed energy deposition print head 130 until the current molten pool area is adjusted in real time to within the preset area range.

[0063] By performing steps S61 to S62, during the continuous printing of the deposition layer, the currently acquired current molten pool area is compared with the previously acquired standard molten pool area. Once it is found that the current molten pool area is larger than the standard molten pool area, immediately reduce the working power of the laser. Once it is found that the current molten pool area is smaller than the standard molten pool area, immediately increase the working power of the laser, realizing the dynamic regulation of the working power of the laser to ensure that the current molten pool area can always be maintained at the same level as the standard molten pool area during the continuous printing of the deposition layer. Therefore, the preset area range is actually a small range of fluctuating areas of the standard molten pool area.

[0064] In some embodiments, step S20: Before starting to print the current layer of the deposition layer, use the optical ranging device 120 to collect the distance between the previous layer of the deposition layer and the signal receiving end of the optical ranging device 120 at a preset frequency to obtain the height of the deposition layer before printing , .

[0065] Thus, before starting to print the deposition layer of the current layer, the laser stops working. The print head driving mechanism 140 is used to drive the directed energy deposition print head 130 to drive the optical ranging device 120 to move along the scanning path, and a plurality of pre-print deposition layer heights are acquired during the movement. .

[0066] Further, in some embodiments, step S70 is: using the optical ranging device 120 to collect the distance between the deposition layer of the current layer and the signal receiving end of the optical ranging device 120 at a preset frequency to obtain the current deposition layer height. , .

[0067] Thus, after the deposition layer of the current layer is printed, the laser stops working. The print head driving mechanism 140 is used to drive the directed energy deposition print head 130 to drive the optical ranging device 120 to move above the deposition layer of the current layer along the scanning path, and a plurality of current deposition layer heights are acquired by using the optical ranging device 120 during the movement. .

[0068] Please refer to Figure 8 together. Further, in some embodiments, step S80 includes step S81 and step S82.

[0069] Step S81, perform a difference calculation on and to obtain the height difference of the deposition layer of the current layer. , .

[0070] Specifically, according to the formula calculate the height difference of the current layer . That is to say , , ……, . Therefore, the height difference of the deposition layer of the current layer is and the absolute value of the difference between them.

[0071] Step S82 uses the formula , perform an average calculation on the height difference of the deposition layer of the current layer to obtain the average value of the actual layer height of the deposition layer of the current layer .

[0072] Please refer to Figure 9 together. Step S90 includes steps S91 to S94.

[0073] Step S91, when the average value of the actual layer height of the deposition layer of the current layer Greater than the preset layer height value When it is, record the height difference of the current layer deposition layer Greater than the preset layer height value Position segment coordinates of.

[0074] Step S92, use the print head driving mechanism 140 to drive the directed energy deposition print head 130 to process the height difference of the current layer deposition layer Greater than the preset layer height value The position segment of is remelted.

[0075] Step S93, use the optical ranging device 120 to collect the distance between the remelted processing part and the signal receiving end of the optical ranging device 120 to obtain the average value of the actual layer height of the remelted processing part .

[0076] Step S94, when the average value of the actual layer height of the remelted processing part Greater than the preset layer height value When it is, return to repeat steps S91 to S93 until the average value of the actual layer height of the remelted processing part Is less than the preset layer height value.

[0077] In step S94, when the actual layer height of the remelted processing part Greater than the preset layer height value When it is, return to repeat steps S91 to S93 one or more times until the actual layer height of the remelted processing part When it is less than the preset layer height value, execute step S100.

[0078] By executing steps S91 to S94, it is ensured that the parts in the current layer deposition layer with an actual layer height greater than the preset layer height value are thinned to a degree where the actual layer height is less than or equal to the preset layer height value, ensuring that before printing the next layer deposition layer, the average value of the actual layer height of the current layer deposition layer is less than the preset layer height value, thereby achieving precise control of the layer height of all deposition layers and ensuring that the layer heights of all deposition layers are uniform.

[0079] The technical features of the above-described embodiments can be combined arbitrarily. For the sake of brevity of description, not all possible combinations of the technical features in the above embodiments are described. However, as long as there is no contradiction in the combination of these technical features, it should be considered to be within the scope described in this specification.

[0080] The above-described embodiments merely represent several implementation manners of the present invention. The description thereof is relatively specific and detailed, but it should not be construed as a limitation on the scope of the invention patent. It should be noted that for those of ordinary skill in the art, without departing from the concept of the present invention, several modifications and improvements can still be made, and these all fall within the protection scope of the present invention. Therefore, the protection scope of the present invention patent shall be subject to the appended claims.

Claims

1. A detection and control method for high uniformity of directed energy deposition, characterized in that Including the steps: Providing a laser deposition printing system; the deposition printing system includes a molten pool vision monitoring device, an optical ranging device, a directed energy deposition printing head, and a printing head driving mechanism; both the molten pool vision monitoring device and the optical ranging device are installed on the directed energy deposition printing head; Before starting to print the deposition layer of the current layer, using the optical ranging device to collect the distance between the deposition layer of the previous layer and the signal receiving end of the optical ranging device to obtain the height of the deposition layer before printing; Using the printing head driving mechanism to drive the directed energy deposition printing head to perform deposition printing on the deposition layer of the previous layer, and using the molten pool vision monitoring device to collect the molten pool area within a preset time period before the collection time point to obtain the standard molten pool area; Recording the printing position corresponding to the collection time point to obtain the break point position; Using the printing head driving mechanism to drive the directed energy deposition printing head to continue deposition printing starting from the break point position, and using the molten pool vision monitoring device to collect the molten pool area in real time at a preset frequency to obtain the current molten pool area; While continuing deposition printing starting from the break point position, according to the standard molten pool area and the current molten pool area, performing real-time regulation on the working power of the laser that provides the printing laser beam for the directed energy deposition printing head to stabilize the current molten pool area within a preset area range; Using the optical ranging device to collect the distance between the deposition layer of the current layer and the signal receiving end of the optical ranging device to obtain the height of the current deposition layer; Calculating the difference between the height of the current deposition layer and the height of the deposition layer before printing to obtain the actual layer height of the deposition layer of the current layer; When the average value of the actual layer height of the deposition layer of the current layer is greater than the preset layer height value, using the printing head driving mechanism to drive the directed energy deposition printing head to remelt the position on the deposition layer where the actual layer height is greater than the preset layer height value until the average value of the actual layer height of the remelted part is less than or equal to the preset layer height value; When the average value of the actual layer height of the deposition layer of the current layer is less than or equal to the preset layer height value, then return to execute the step of obtaining the height of the deposition layer before printing to print the deposition layer of the next layer.

2. The detection and control method for high uniformity of the directed energy deposition layer according to claim 1, wherein The sampling time interval of the optical ranging device is ; where is the minimum linear distance in the scanning path, is the scanning speed of the laser deposition printing system; The total time taken for the laser deposition printing system to complete printing one deposition layer is ; where is the total path length of the directed energy deposition print head to complete printing one deposition layer; The number of sampling times of the optical ranging device on a deposition layer is .

3. The detection and control method for high uniformity of the directed energy deposition layer according to claim 1, characterized in that The optical ranging device is configured such that the laser beam emitted can be vertically incident on the deposition layer or the tabletop of the workbench.

4. The detection and control method for high uniformity of the directed energy deposition layer according to claim 1, wherein The step of using the printing head driving mechanism to drive the directed energy deposition printing head to perform deposition printing on the deposition layer of the previous layer, and using the molten pool vision monitoring device to collect the molten pool area within a preset time period before the collection time point to obtain the standard molten pool area includes: Using the printing head driving mechanism to drive the directed energy deposition printing head to perform deposition printing on the deposition layer of the previous layer; While depositing and printing, the molten pool vision monitoring device is used to collect the molten pool area within a preset time period before the acquisition time point to obtain a set of area image data; Extract data features from the area image data and calculate according to the formula to obtain the molten pool area in the th area image data ; where is the longest side of the molten pool image in the th area image data, and is the shortest side of the molten pool image in the th area image data; According to the formula for the molten pool areas of a number of sampling points, perform mean calculation to obtain the standard molten pool area .

5. The detection and control method for high uniformity of the directed energy deposition layer according to claim 1, characterized in that, Using the print head driving mechanism to drive the directed energy deposition print head to continue deposition printing starting from the breakpoint position, and using the molten pool vision monitoring device to collect the molten pool area in real time to obtain the current molten pool area, the steps include: using the print head driving mechanism to drive the directed energy deposition print head to continue deposition printing starting from the breakpoint position; While continuing deposition printing, using the molten pool vision monitoring device to collect the molten pool area in real time to obtain the current area image; Extract data features from the current area image and calculate the current molten pool area according to the following formula :[[]] ; Among them, is the longest side of the molten pool image in the current area image, is the shortest side of the molten pool image in the current area image.

6. The detection and control method for high uniformity of the directed energy deposition layer according to claim 1, characterized in that, According to the standard molten pool area and the current molten pool area, the steps of performing real-time regulation on the working power of the laser that provides the printing laser beam for the directed energy deposition print head include: Comparing the current molten pool area with the standard molten pool area; If the current molten pool area is smaller than the standard molten pool area, increasing the working power of the laser that provides the printing laser beam for the directed energy deposition print head until the current molten pool area is regulated in real time to within the preset area range; If the current molten pool area is larger than the standard molten pool area, then reducing the working power of the laser that provides the printing laser beam for the directed energy deposition print head until the current molten pool area is regulated in real time to within the preset area range.

7. The detection and control method for high uniformity of the directed energy deposition layer according to claim 1, characterized in that When the deposited layer of the current layer is the first deposited layer, the step of obtaining the height of the deposited layer before printing is: before starting to print the deposited layer of the current layer, using the optical ranging device to collect the distance between the tabletop of the workbench in the laser deposition printing system and the signal receiving end of the optical ranging device to obtain the height of the deposited layer before printing.

8. The detection and control method for high uniformity of the directed energy deposition layer according to claim 1, characterized in that The steps for obtaining the height of the deposited layer before printing include: before starting to print the deposited layer of the current layer, using the optical ranging device to collect the distance between the deposited layer of the previous layer and the signal receiving end of the optical ranging device at a preset frequency, so as to obtain the height of the deposited layer before printing , .

9. The detection and control method for high uniformity of the directed energy deposition layer according to claim 8, characterized in that, The step of using the optical ranging device to collect the distance between the deposited layer of the current layer and the signal receiving end of the optical ranging device to obtain the current deposited layer height is: The optical ranging device is used to collect the distance between the deposited layer of the current layer and the signal receiving end of the optical ranging device at the preset frequency, so as to obtain the height of the deposited layer , .

10. The detection and control method for high uniformity of the directed energy deposition layer according to claim 9, characterized in that The steps of calculating the difference between all the deposited layer heights and the deposited layer before printing to obtain the actual layer height of the deposited layer of the current layer include: Pair and Perform a difference calculation to obtain the height difference of the deposition layer of the current layer , ; Using the formula , calculate the mean value of the height difference of the current layer deposition layer to obtain the mean value of the actual layer height of the current layer deposition layer; When the average value of the actual layer height of the deposited layer of the current layer is greater than the preset layer height value, the step of using the print head driving mechanism to drive the directed energy deposition print head to remelt the position on the deposited layer where the actual layer height is greater than the preset layer height value includes: When the mean value of the actual layer height of the current deposited layer is greater than the preset layer height value record the position segment coordinates where the height difference of the current deposited layer is greater than the preset layer height value ; Use the print head driving mechanism to drive the directed energy deposition print head to remelt and process the position segment where the height difference of the current layer deposition layer is greater than the preset layer height value ; The distance between the remelting processing part and the signal receiving end of the optical ranging device is collected by using the optical ranging device, so as to obtain the average value of the actual layer height of the remelting processing part ; When the mean value of the actual layer height of the remelting and processing part is greater than the preset layer height value , return the step of executing the record of the height difference of the deposition layer of the current layer greater than the preset layer height value of the position segment coordinates.

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