Detection and control method for high uniformity of directed energy deposition layer

Abstract

The present invention relates to a method for detecting and controlling the uniformity of the height of a directed energy deposition layer. By executing the above-mentioned method for detecting and controlling the uniformity of the directed energy deposition layer, precise control of the molten pool area and the operating power of the laser can be achieved during the deposition layer printing process. Precise control of the molten pool area during the deposition layer printing process can also achieve precise control of the height of each deposition layer. By precisely controlling the consistency and uniformity of the height of all deposition layers during the deposition printing process, the problems of unstable deposition layer height and uneven surface are solved, and the probability of part defects and performance problems caused by inconsistent layer height and excessive errors is reduced, thereby reducing subsequent processing allowances and scrap rates, and reducing the probability of human intervention in the deposition layer height correction during the entire deposition printing process, thereby improving deposition printing efficiency.

Description

Technical Field

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

[0002] As an advanced manufacturing technology, laser directed energy deposition additive manufacturing technology has the advantages of flexible material feeding methods, high molding efficiency and degree of freedom, and strong feasibility of multi-process composite. It can solve the problems of high-efficiency, high-performance and high-precision manufacturing of large-scale integrated equipment, multi-material integration, complex surfaces and other components. It has been widely used in aerospace, navigation, automobile and rail transportation, energy and power and other fields.

[0003] Currently, existing technologies all rely on collecting the center temperature and size of the melt pool to establish a functional relationship between the melt pool temperature and laser power, material feed speed, and scanning speed, thereby controlling print layer height defects and improving print quality. However, this method of controlling print layer height defects by collecting the center temperature and size of the melt pool and establishing a functional relationship between various printing parameters has the following problems:

[0004] During the printing and deposition manufacturing process of metal parts, due to the influence of multiple factors, such as powder properties, wire properties (such as slight differences in wire diameter, tension fluctuations during wire feeding, uneven wire melting, changes in metal cooling and solidification conditions, laser energy input stability, molten pool dynamics, and the matching of acceleration and deceleration changes of the motion system with input energy), etc., the printing system is difficult to accurately control the uniformity of the deposition printing height of each layer, and a single deposition layer will show a wave-like height change. The large height difference of the deposition layer will affect the dimensional accuracy, surface quality and internal structural integrity of the part. As the layer height error of the deposition layer accumulates too large, it will directly cause changes in the laser energy focus and the molten pool, causing changes in the positional relationship between the powder or wire and the laser energy beam, making it impossible to continue the printing and deposition process. Summary of the Invention

[0005] Based on this, it is necessary to provide a detection and control method for the high uniformity of the directed energy deposition layer that can achieve precise control of the high uniformity of the deposition layer to improve the accuracy and quality of the deposition-printed products.

[0006] A method for detecting and controlling the high uniformity of a directed energy deposition layer, comprising the steps of:

[0007] A laser deposition printing system is provided; the deposition printing system includes a molten pool visual monitoring device, an optical ranging device, a directed energy deposition print head, and a print head drive mechanism; the molten pool visual monitoring device and the optical ranging device are both installed on the directed energy deposition print head;

[0008] Before starting to print the current deposition layer, using the optical distance measuring device to collect the distance between the previous deposition layer and the signal receiving end of the optical distance measuring device to obtain the height of the deposition layer before printing;

[0009] Using the print head drive mechanism to drive the directed energy deposition print head to perform deposition printing on the previous deposition layer, and using the molten pool visual monitoring device to collect the molten pool area within a preset time period before the collection time point to obtain a standard molten pool area;

[0010] Recording the printing position corresponding to the acquisition time point to obtain the breakpoint position;

[0011] Using the print head drive mechanism to drive the directed energy deposition print head to continue deposition printing from the breakpoint position, and using the molten pool visual monitoring device to collect the molten pool area in real time at a preset frequency to obtain the current molten pool area;

[0012] While continuing deposition printing from the breakpoint position, the operating power of a laser providing a printing laser beam to the directed energy deposition print head is controlled in real time according to the standard melt pool area and the current melt pool area, so as to stabilize the current melt pool area within a preset area range;

[0013] Using the optical distance measuring device to collect the distance between the current sediment layer and the signal receiving end of the optical distance measuring device to obtain the current sediment layer height;

[0014] Calculating the difference between the current deposition layer height and the deposition layer height before printing to obtain the actual layer height of the current deposition layer;

[0015] When the average value of the actual layer height of the current deposited layer is greater than the preset layer height value, the print head driving mechanism drives the directed energy deposition print head to perform remelting processing on the position of the deposited 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 portion is less than or equal to the preset layer height value;

[0016] When the average value of the actual layer height of the current deposition layer is less than or equal to the preset layer height value, the process returns to the step of obtaining the height of the deposition layer before printing to print the next deposition layer.

[0017] The above-mentioned method for detecting and controlling the layer height uniformity of directed energy deposition first obtains a standard melt pool area during the printing process of each deposition layer, then simultaneously obtains the current melt pool area in real time during the deposition printing process, and adjusts the laser operating power in real time based on the comparison result between the standard melt pool area and the current melt pool area, so as to stabilize the current melt pool area within a preset area range during the deposition printing process, thereby achieving adaptive control of the melt pool area and laser operating power during the deposition layer printing process; the actual layer height of the current deposition layer is obtained by detecting the pre-printing deposition layer height (i.e., the height of the previous deposition layer) and the current deposition layer height, and the portion of the current deposition layer with an actual layer height greater than the preset layer height value is thinned to an actual layer height less than or equal to the preset layer height value through remelting processing, thereby achieving precise control of the layer height of each deposition layer. The implementation process of the above-mentioned method for detecting and controlling the layer height uniformity of directed energy deposition is fully automated, eliminating the need for human intervention and correction of the deposition layer height, melt pool area, and laser operating power, thereby reducing the risk of human intervention.

[0018] Therefore, the above-mentioned detection and control method for the uniformity of the height of the directed energy deposition layer achieves precise control of the height of each deposition layer by precisely controlling the molten pool area and the laser working power during the deposition layer printing process, and precisely controls the layer height consistency and uniformity of all deposition layers during the deposition printing process, thereby solving the problems of unstable layer height and uneven surface of the deposition layer, reducing the probability of part defects and performance problems caused by inconsistent layer height and excessive errors, thereby reducing subsequent processing allowances and scrap rates, and reducing the probability of human correction and intervention in the deposition layer height during the entire deposition printing process, thereby improving the deposition printing efficiency. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] Figure 1 Schematic diagram of the flow of a method for detecting and controlling the high uniformity of a directed energy deposition layer in a preferred embodiment of the present invention;

[0020] Figure 2 for Figure 1 A schematic structural diagram of the laser deposition printing system provided in step S10 of the method for detecting and controlling high uniformity of a directed energy deposition layer shown;

[0021] Figure 3 for Figure 1 Schematic diagram of the process of step S30 in the method for detecting and controlling the high uniformity of the directed energy deposition layer;

[0022] Figure 4 for Figure 1 A schematic diagram of a molten pool diagram involved in step S33 of the method for detecting and controlling high uniformity of a directed energy deposition layer is shown;

[0023] Figure 5 for Figure 1 Schematic diagram of the flow of step S50 in the method for detecting and controlling the high uniformity of the directed energy deposition layer;

[0024] Figure 6 for Figure 1 A schematic diagram of a molten pool diagram involved in step S53 of the method for detecting and controlling high uniformity of a directed energy deposition layer is shown;

[0025] Figure 7 for Figure 1 Schematic diagram of the process of step S60 in the method for detecting and controlling the high uniformity of the directed energy deposition layer;

[0026] Figure 8 for Figure 1 Schematic diagram of the flow of step S80 in the method for detecting and controlling the high uniformity of a directed energy deposition layer;

[0027] Figure 9 for Figure 1 FIG. 1 is a flow chart of step S90 in the method for detecting and controlling the high uniformity of a directed energy deposition layer.

[0028] Description of the accompanying drawings in the specific implementation manner: 100, laser deposition printing system; 110, molten pool visual monitoring device; 120, optical ranging device; 130, directed energy deposition print head; 140, print head drive mechanism; 160, workbench; 170, loading device; 180, computer control system. DETAILED DESCRIPTION

[0029] To facilitate understanding of the present invention, the present invention will be described more fully below with reference to the accompanying drawings. Preferred embodiments of the present invention are shown in the accompanying drawings. However, the present invention may be implemented in many different forms and is not limited to the embodiments described herein. Rather, these embodiments are provided to provide a more thorough and comprehensive understanding of the present disclosure.

[0030] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one skilled in the art to which this invention pertains. The terms used in this specification of the present invention are for the purpose of describing specific embodiments only and are not intended to limit the present invention. The term "and / or" as used herein includes any and all combinations of one or more of the associated listed items.

[0031] When describing positional relationships, unless otherwise specified, when an element is referred to as being "on" another element, it can be directly on the other element or intervening elements may also exist. It is also understood that when an element is referred to as being "between" two elements, it can be the only one between the two elements, or one or more intervening elements may also exist.

[0032] In the case of using “including,” “having,” and “comprising” described herein, another component may be added unless a clear limiting term such as “only,” “consisting of,” etc. is used. Unless mentioned otherwise, a term in the singular form may include a plural form and should not be understood as having one number.

[0033] See also Figure 1 The method for detecting and controlling the height of a directed energy deposition layer in a preferred embodiment of the present invention includes steps S10 to S100.

[0034] Please also refer to Figure 2 In step S10, a laser deposition printing system 100 is provided. The deposition printing system includes a melt pool visual monitoring device 110, an optical distance measuring device 120, a directed energy deposition print head 130, and a print head drive mechanism 140. The melt pool visual monitoring device 110 and the optical distance measuring device 120 are both mounted 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 onto a workbench 160.

[0035] To ensure the measurement accuracy of the optical distance measuring device 120 , in one embodiment, the detection laser beam emitted by the optical distance measuring device 120 is perpendicular to the deposition layer or the table surface of the workbench 160 in the laser deposition printing system 100 .

[0036] Of course, in other embodiments, the detection laser beam emitted by the optical distance measuring device 120 may also be incident obliquely onto the deposition layer or the surface of the workbench 160 .

[0037] Step S20 , before starting to print the current deposition layer, the optical distance measuring device 120 is used to collect the distance between the previous deposition layer and the signal receiving end of the optical distance measuring device 120 to obtain the height of the deposition layer before printing.

[0038] Specifically, before starting to print the current deposition layer, the optical distance measuring device 120 is used to collect the distance between the table surface of the workbench 160 in the laser deposition printing system 100 and the signal receiving end of the optical distance measuring device 120 to obtain the height of the deposition layer before printing.

[0039] In step S30, the print head driving mechanism 140 drives the directed energy deposition print head 130 to perform deposition printing on the previous deposition layer, and the molten pool visual monitoring device 110 is used to collect the molten pool area within a preset time period before the collection time point to obtain a standard molten pool area.

[0040] Specifically, within a preset time period before the collection time point, the molten pool visual monitoring device 110 can obtain multiple sets of detection data, and obtain the guaranteed molten pool area by performing mean calculation on the multiple sets of detection data.

[0041] When executing step S30, if the current deposition layer is the first deposition layer, the print head driving mechanism 140 is used to drive the directed energy deposition print head 130 to perform deposition printing on the table surface of the workbench 160, and the molten pool visual monitoring device 110 is used to collect the molten pool area within a preset time period before the collection time point to obtain the standard molten pool area.

[0042] Step S40 , recording the printing position corresponding to the acquisition time point to obtain the breakpoint position.

[0043] The printing position is the location where the printing laser beam emitted by the directed energy deposition print head 130 impinges on the deposited layer at the acquisition time point, and the printing of the deposited layer is briefly interrupted at this location to provide time for data processing of the acquired data. By executing step S40, the position coordinates of the breakpoint location are recorded.

[0044] In step S50 , the print head driving mechanism 140 is used to drive the directed energy deposition print head 130 to continue deposition printing from the breakpoint position, and the molten pool visual monitoring device 110 is used to collect the molten pool area in real time at a preset frequency to obtain the current molten pool area.

[0045] Step S60, while executing step S50, the laser operating power that provides the printing laser beam to the directed energy deposition print head 130 is adjusted in real time according to the standard melt pool area and the current melt pool area to stabilize the current melt pool area within a preset area range.

[0046] In step S70 , the optical distance measuring device 120 is used to collect the distance between the current deposition layer and the signal receiving end of the optical distance measuring device 120 to obtain the height of the current deposition layer.

[0047] It should be noted that the current deposition layer height is actually the distance between the current deposition layer and the signal receiving end of the optical ranging device. Of course, in other embodiments, the current deposition layer height can also be understood as the actual height of the current deposition layer with the workbench surface as a reference. This actual height is calculated by converting the distance between the current deposition layer and the signal receiving end of the optical ranging device.

[0048] Step S80 , calculating the difference between the current deposition layer height and the deposition layer height before printing to obtain the actual layer height of the current deposition layer.

[0049] Step S90, when the average value of the actual layer height of the current deposition layer is greater than the preset layer height value, the print head drive mechanism 140 is used to drive the directed energy deposition print head 130 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 portion is less than or equal to the preset layer height value.

[0050] In step S100, when the average actual layer height of the current deposition layer is less than or equal to the preset layer height value, the process returns to and repeats steps S20 to S90 to print the next deposition layer until a precision-manufactured part is obtained by stacking printing.

[0051] It should be noted that during the remelting process, the loading device 170 is controlled to stop working to stop conveying metal powder or metal wire to the workbench 160. At the same time, the print head drive mechanism 140 drives the directed energy deposition print head 130 to perform laser scanning on the part of the current deposition layer where the actual layer height is greater than the preset layer height value, so as to thin the part of the current deposition layer where the layer height is too high.

[0052] It should also be noted that all data processing in steps S20 to S100 and the automated operation of each part of the laser deposition printing system 100 are respectively implemented by the data processing module and the control module in the computer control system 180.

[0053] 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 deposition layer of the current layer, and the current molten pool area is obtained in real time in the middle and late stages of printing the deposition layer of the current layer. These current molten pool areas are compared with the standard molten pool areas, and the working power of the laser is then adjusted in real time according to the comparison structure to ensure that the current molten pool area can be stabilized within the preset area range, thereby realizing adaptive adjustment of the molten pool area and the laser working power during the deposition layer printing process.

[0054] During the printing process of each deposition layer, stabilizing the melt pool area within a preset area range can avoid problems such as poor surface quality of the deposited layer due to an excessively large melt pool area, which can easily produce wavy surfaces. It can also avoid problems such as incomplete fusion of metal powder or metal wire due to an excessively small melt pool area, which can lead to pores and incompletely melted areas within the part. This effectively improves the surface quality of the deposited layer and the product quality of the deposited printed parts. Moreover, through real-time regulation of the laser operating power, not only can the melt pool area be stabilized, but the height of the deposited layer can also be stabilized within a specific layer height range.

[0055] By executing step S20, step S70 to step S100, the height of the deposition layer before printing (i.e., the height of the deposition layer of the previous layer) is obtained before the deposition layer is printed, the current deposition layer height is obtained after the current deposition layer is printed, and the actual layer height of the current deposition layer is calculated by the height of the deposition layer before printing and the current deposition layer height. The part of the current deposition layer whose actual layer height is greater than the preset layer height value is thinned to an actual layer height less than or equal to the preset layer height value by remelting processing, so as to achieve precise control of the layer height of each deposition layer.

[0056] During the execution of steps S10 to S100, the optical ranging device 120, the molten pool visual monitoring device 110 and the print head drive mechanism 140 cooperate with each other to realize the full automation of the entire execution process of the above-mentioned directional energy deposition layer height uniformity detection and control method. The entire process does not require human intervention and correction of the deposition layer height, molten pool area and laser working power, reducing the risk of human intervention.

[0057] Therefore, the above-mentioned detection and control method for the uniformity of the height of the directed energy deposition layer achieves precise control of the height of each deposition layer by precisely controlling the molten pool area and the laser working power during the deposition layer printing process, and precisely controls the layer height consistency and uniformity of all deposition layers during the deposition printing process, thereby solving the problems of unstable layer height and uneven surface of the deposition layer, reducing the probability of part defects and performance problems caused by inconsistent layer height and excessive errors, thereby reducing subsequent processing allowances and scrap rates, and reducing the probability of human correction and intervention in the deposition layer height during the entire deposition printing process, thereby improving the deposition printing efficiency.

[0058] In some embodiments, the sampling time interval of the optical distance measuring device 120 is for .in, is the minimum linear distance in the scan path, is the scanning speed of the laser deposition printing system 100 .

[0059] The total time it takes for the laser deposition printing system 100 to print a deposition layer for .in, The total path length for the directed energy deposition print head 130 to print one deposition layer.

[0060] The number of sampling times of the optical distance measuring device 120 on a sediment layer for: .

[0061] Therefore, the data acquisition frequency of the optical distance measuring device 120 is , periodic data collection can be performed. When the scanning speed of the 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 are known, the collection time interval of the optical distance measuring device 120 and the number of collection times required to complete a deposition layer can be easily obtained, so as to facilitate the recording of the collection data for each deposition layer and subsequent calculations.

[0062] Therefore, when executing step S20, the optical distance measuring device 120 collects the distance between the previous deposition layer and the signal receiving end of the optical distance measuring device 120 to obtain multiple data points, and then calculates the height of the deposition layer before printing based on the multiple data points. Similarly, when executing step S70, the optical distance measuring device 120 also obtains multiple data points through periodic data collection, and then calculates the current deposition layer height based on these data points to improve the accuracy of deposition layer height measurement.

[0063] In some embodiments, the optical distance measuring device 120 is configured to allow the laser beam emitted by it to be vertically irradiated on the deposition layer or the surface of the workbench 160 to ensure the accuracy of the measurement data of the optical distance measuring device 120.

[0064] Please also refer to Figure 3 In some embodiments, step S30 includes steps S31 to S34.

[0065] In step S31 , the print head driving mechanism 140 is used to drive the directed energy deposition print head 130 to perform deposition printing on the previous deposition layer.

[0066] Of course, when the current deposition layer is the first deposition layer in the deposition printing process, when executing step S31 , the directed energy deposition print head 130 performs deposition printing on the table surface of the workbench 160 .

[0067] Step S32: While executing step S31, the molten pool visual monitoring device 110 is used to collect the molten pool area within a preset time period before the collection time point to obtain Area image data.

[0068] Please also refer to Figure 4 , step S33, extracting data features from the area image data, and using the formula Calculate the first The melt pool area in the area image data .in, For the The longest side of the melt pool image in the area image data, For the The shortest side of the melt pool image in the area image data.

[0069] By executing step S33, data features are extracted from the area image data to obtain the longest side and the shortest side of the molten pool image in each surface image data, and the area of ​​the molten pool image is calculated using the longest side and the shortest side of the molten pool image according to the area calculation formula of the approximate ellipse.

[0070] Step S34, according to the formula right The molten pool area of ​​each sampling point Perform mean calculation to obtain the standard melt pool area .

[0071] By executing steps S31 to S33, the The area image data of each area image data is obtained, and the molten pool area corresponding to each area image data is calculated according to the area calculation formula of the approximate ellipse. By executing step S34, the area image data obtained in the preset time period before the sampling time period is calculated. The average of the molten pool areas is calculated to obtain a more accurate standard molten pool area, which provides strong support for the precise real-time control of the subsequent laser working power.

[0072] Please also refer to Figure 5 In some embodiments, step S50 includes steps S51 to S53.

[0073] In step S51 , the print head driving mechanism 140 is used to drive the directed energy deposition print head 130 to continue deposition printing from the breakpoint position.

[0074] Step S52: While executing step S51, the molten pool area is collected using the molten pool visual monitoring device 110 to obtain a current area image.

[0075] Please also refer to Figure 6 In step S53, data features are extracted from the current area image, and the current molten pool area is calculated according to the following formula: : .

[0076] in, is the longest side of the melt pool image in the current area image, It is the shortest side of the melt pool image in the current area image.

[0077] By executing step S51, the printing of the deposition layer begins at the breakpoint, avoiding repeated laser scanning or unmelted metal powder or wire, further ensuring the quality of the deposition printing. By executing steps S52 and S53, image acquisition, data feature extraction of the acquired image, and data calculation of the extracted features are achieved to obtain the current melt pool area. Therefore, by executing steps S51 to S53, the current melt pool area can be obtained in real time while ensuring the printing quality of the deposition layer.

[0078] Please also refer to Figure 7 In some embodiments, step S60 includes steps S61 to S63.

[0079] Step S61: compare the current molten pool area with the standard molten pool area.

[0080] In step S62 , if the current molten pool area is smaller than the standard molten pool area, the operating power of the laser providing the printing laser beam to the directed energy deposition print head 130 is increased until the current molten pool area is adjusted in real time to be within the preset area range.

[0081] In step S63 , if the current molten pool area is larger than the standard molten pool area, the operating power of the laser providing the laser beam to the directed energy deposition print head 130 is reduced until the current molten pool area is adjusted in real time to be within the preset area range.

[0082] By executing steps S61 to S62, the current molten pool area obtained in real time is compared with the standard molten pool area obtained in the early stage during the continued printing of the deposition layer. Once it is found that the current molten pool area is larger than the standard molten pool area, the laser working power is immediately reduced. Once it is found that the current molten pool area is smaller than the standard molten pool area, the laser working power is immediately increased to achieve dynamic regulation of the laser working power to ensure that the current molten pool area can always be maintained at a level consistent with the standard molten pool area during the continued printing of the deposition layer. Therefore, the preset area range is actually a small range of fluctuation area of ​​the standard molten pool area.

[0083] In some embodiments, step S20: before starting to print the current deposition layer, the optical distance measuring device 120 is used to collect the distance between the previous deposition layer and the signal receiving end of the optical distance measuring device 120 at a preset frequency to obtain the height of the deposition layer before printing. , .

[0084] In this way, before starting to print the current deposition layer, the laser stops working, and the print head drive mechanism 140 drives the directed energy deposition print head 130 to drive the optical distance measuring device 120 to move along the scanning path, and collects and obtains the height of multiple deposition layers before printing during the movement. .

[0085] Furthermore, in some embodiments, step S70 is: using the optical distance measuring device 120 to collect the distance between the current sediment layer and the signal receiving end of the optical distance measuring device 120 at a preset frequency to obtain the current sediment layer height , .

[0086] In this way, after the current deposition layer is printed, the laser stops working, and the print head drive mechanism 140 drives the directed energy deposition print head 130 to drive the optical distance measuring device 120 to move above the current deposition layer according to the scanning path, and during the movement, the optical distance measuring device 120 is used to collect and obtain multiple current deposition layer heights. .

[0087] Please also refer to Figure 8 Furthermore, in some embodiments, step S80 includes step S81 and step S82.

[0088] Step S81: and Perform difference calculation to obtain the height difference of the current sediment layer , .

[0089] Specifically, according to the formula Calculate the height difference of the current layer That is to say , ,……, Therefore, the height difference of the current sedimentary layer for and The absolute value of the difference between .

[0090] Step S82 uses the formula , the height difference of the current sedimentary layer Perform mean calculation to obtain the mean of the actual layer height of the current deposition layer .

[0091] Please also refer to Figure 9 , step S90 includes steps S91 to S94.

[0092] Step S91: When the average actual layer height of the current deposition layer is Greater than the preset layer height value When the height difference of the current sediment layer is recorded Greater than the preset layer height value The position segment coordinates.

[0093] Step S92: Use the print head drive mechanism 140 to drive the directed energy deposition print head 130 to deposit the height difference of the current layer. Greater than the preset layer height value The position segment is remelted.

[0094] Step S93: Use the optical distance measuring device 120 to collect the distance between the remelting processing part and the signal receiving end of the optical distance measuring device 120 to obtain the average value of the actual layer height of the remelting processing part. .

[0095] Step S94: when the average actual layer height of the remelting processing part is Greater than the preset layer height value When the actual layer height of the remelting part is 0, the process returns to step S91 to step S93 and repeats until the average layer height of the remelting part is 0. Smaller than the preset layer height value.

[0096] In step S94, when the actual layer height of the remelting processing part Greater than the preset layer height value When the actual layer height of the remelting part is When the height is less than the preset floor height value, step S100 is executed.

[0097] By executing steps S91 to S94, it is ensured that the parts of the current deposition layer whose actual layer height is 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, and that before printing the next deposition layer, the average actual layer height of the current 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 height of all deposition layers is uniform.

[0098] The technical features of the above-mentioned embodiments can be combined arbitrarily. In order to make the description concise, not all possible combinations of the technical features in the above-mentioned embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0099] The above-described embodiments merely illustrate several implementations of the present invention, and while their descriptions are relatively specific and detailed, they should not be construed as limiting the scope of the patent. It should be noted that a person skilled in the art would be able to make numerous variations and improvements without departing from the spirit of the present invention, all of which fall within the scope of protection of the present invention. Therefore, the scope of protection of the patent for this invention shall be determined by the appended claims.

Claims

1. A method for detecting and controlling the high uniformity of a directed energy deposition layer, characterized in that: Including steps: A laser deposition printing system is provided; the deposition printing system includes a molten pool visual monitoring device, an optical ranging device, a directed energy deposition print head, and a print head drive mechanism; the molten pool visual monitoring device and the optical ranging device are both installed on the directed energy deposition print head; Before starting to print the current deposition layer, using the optical distance measuring device to collect the distance between the previous deposition layer and the signal receiving end of the optical distance measuring device to obtain the height of the deposition layer before printing; Using the print head drive mechanism to drive the directed energy deposition print head to perform deposition printing on the previous deposition layer, and using the molten pool visual monitoring device to collect the molten pool area within a preset time period before the collection time point to obtain a standard molten pool area; Recording the printing position corresponding to the acquisition time point to obtain the breakpoint position; Using the print head drive mechanism to drive the directed energy deposition print head to continue deposition printing from the breakpoint position, and using the molten pool visual 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 from the breakpoint position, the operating power of a laser providing a printing laser beam to the directed energy deposition print head is controlled in real time according to the standard melt pool area and the current melt pool area, so as to stabilize the current melt pool area within a preset area range; Using the optical distance measuring device to collect the distance between the current sediment layer and the signal receiving end of the optical distance measuring device to obtain the current sediment layer height; Calculating the difference between the current deposition layer height and the deposition layer height before printing to obtain the actual layer height of the current deposition layer; When the average value of the actual layer height of the current deposited layer is greater than the preset layer height value, the print head driving mechanism drives the directed energy deposition print head to perform remelting processing on the position of the deposited 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 portion is less than or equal to the preset layer height value; When the average value of the actual layer height of the current deposition layer is less than or equal to the preset layer height value, the process returns to the step of obtaining the height of the deposition layer before printing to print the next deposition layer.

2. The method for detecting and controlling the high uniformity of a directed energy deposition layer according to claim 1, characterized in that: The sampling time interval of the optical distance measuring device for ;in, is the minimum linear distance in the scan path, is the scanning speed of the laser deposition printing system; The total time taken by the laser deposition printing system to print a deposition layer for ;in, The total path length for a directed energy deposition printhead to print one deposition layer; The number of sampling times of the optical distance measuring device on a sediment layer for .

3. The method for detecting and controlling the high uniformity of a directed energy deposition layer according to claim 1, characterized in that: The optical distance measuring device is configured to emit a laser beam that is vertically irradiated on the deposition layer or the surface of the workbench.

4. The method for detecting and controlling the high uniformity of a directed energy deposition layer according to claim 1, characterized in that: The step of using the print head driving mechanism to drive the directed energy deposition print head to perform deposition printing on the previous deposition layer, and using the molten pool visual monitoring device to collect the molten pool area within a preset time period before the collection time point to obtain a standard molten pool area includes: Using the print head drive mechanism to drive the directed energy deposition print head to perform deposition printing on the previous deposition layer; During deposition printing, the molten pool visual monitoring device is used to collect the molten pool area within a preset time period before the collection time point to obtain Area image data; Extract data features from the area image data and calculate the feature according to the formula Calculate the first The melt pool area in the area image data ;in, For the The longest side of the melt pool image in the area image data, For the The shortest side of the melt pool image in the area image data; According to the formula right The molten pool area of ​​each sampling point Perform mean calculation to obtain the standard molten pool area .

5. The method for detecting and controlling the high uniformity of a directed energy deposition layer according to claim 1, characterized in that: The steps of using the print head driving mechanism to drive the directed energy deposition print head to continue deposition printing from the breakpoint position, and using the molten pool visual monitoring device to collect the molten pool area in real time to obtain the current molten pool area include: using the print head driving mechanism to drive the directed energy deposition print head to continue deposition printing from the breakpoint position; While continuing deposition printing, the molten pool area is collected in real time using the molten pool visual monitoring device to obtain a current area image; Data features are extracted from the current area image, and the current molten pool area is calculated according to the following formula: : ; in, is the longest side of the melt pool image in the current area image, It is the shortest side of the melt pool image in the current area image.

6. The method for detecting and controlling the high uniformity of a directed energy deposition layer according to claim 1, characterized in that: The step of regulating in real time the operating power of a laser that provides a printing laser beam to the directed energy deposition print head according to the standard melt pool area and the current melt pool area comprises: 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, the operating power of the laser providing the printing laser beam to the directed energy deposition print head is increased until the current molten pool area is adjusted in real time to be within a preset area range; If the current molten pool area is larger than the standard molten pool area, the operating power of the laser that provides the printing laser beam to the directed energy deposition print head will be reduced until the current molten pool area is adjusted in real time to be within a preset area range.

7. The method for detecting and controlling the high uniformity of a directed energy deposition layer according to claim 1, characterized in that: When the current deposition layer is the first deposition layer, the step of obtaining the height of the deposition layer before printing is: before starting to print the current deposition layer, using the optical ranging device to collect the distance between the table surface 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 deposition layer before printing.

8. The method for detecting and controlling the high uniformity of a directed energy deposition layer according to claim 1, characterized in that: The step of obtaining the height of the deposition layer before printing comprises: before starting to print the deposition layer of the current layer, using the optical distance measuring device to collect the distance between the deposition layer of the previous layer and the signal receiving end of the optical distance measuring device at a preset frequency to obtain the height of the deposition layer before printing. , .

9. The method for detecting and controlling the high uniformity of a directed energy deposition layer according to claim 8, characterized in that: The steps of using the optical distance measuring device to collect the distance between the current sediment layer and the signal receiving end of the optical distance measuring device to obtain the height of the current sediment layer are: The optical distance measuring device is used to collect the distance between the current sediment layer and the signal receiving end of the optical distance measuring device at the preset frequency to obtain the sediment layer height. , .

10. The method for detecting and controlling the high uniformity of a directed energy deposition layer according to claim 9, characterized in that: The step of calculating the difference between the heights of all deposited layers and the deposited layer before printing to obtain the actual layer height of the current deposited layer includes: right and Perform difference calculation to obtain the height difference of the current sediment layer , ; Using the formula , the height difference of the current sedimentary layer Perform mean calculation to obtain the mean of the actual layer height of the current deposition layer ; When the average value of the actual layer height of the current deposited 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 comprises: When the average actual layer height of the current deposition layer Greater than the preset floor height value When the height difference of the current sediment layer is recorded Greater than the preset floor height value The position segment coordinates of The height difference of the current layer deposited by the directional energy deposition print head is driven by the print head driving mechanism. Greater than the preset floor height value The position segment is remelted; The optical distance measuring device is used to collect the distance between the remelting processing part and the signal receiving end of the optical distance measuring device to obtain the average value of the actual layer height of the remelting processing part. ; When the average actual layer height of the remelting processing part Greater than the preset layer height value When the height difference of the current sediment layer is recorded, it returns to execute Greater than the preset floor height value The position segment coordinates of the step.

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