Molten pool radiation information acquisition device and laser powder bed melting equipment

Abstract

The utility model discloses a molten pool radiation information acquisition device and laser powder bed melting equipment. The molten pool radiation information collecting device comprises a space molten pool radiation collecting unit which is arranged on the upper top of the forming cavity and used for collecting space molten pool radiation information of one wave band or multiple wave bands of each machining layer; and the coaxial light path molten pool radiation acquisition unit is arranged in the laser processing light path and is used for acquiring coaxial light path molten pool radiation information of one wave band or multiple wave bands of each processing layer. According to the utility model, the space molten pool radiation acquisition unit and the coaxial light path molten pool radiation acquisition unit are used for respectively acquiring space molten pool radiation information and coaxial light path molten pool radiation information, so that the molten pool radiation information in the melting processing process of the laser powder bed can be more comprehensively acquired; the molten pool radiation information collected by the molten pool radiation information collection device is used as original data of laser powder bed melting quality analysis, and the effectiveness of part internal defect and forming performance prediction can be improved.

Description

Technical Field

[0001] This utility model relates to the field of additive manufacturing technology, and in particular to a molten pool radiation information acquisition device and a laser powder bed melting equipment. Background Technology

[0002] Laser powder bed melting (LPBF) is an additive manufacturing technology that uses a laser beam to melt and solidify metal powder layer by layer at extremely high speeds to form the desired parts. It has a wide range of materials and integrates design and manufacturing. It has significant advantages in the fine manufacturing of complex structures and has been widely used in the manufacturing process of complex components of various equipment.

[0003] During LPBF (Liquid Bed Burner) forming, the interaction between the laser and metal powder causes drastic changes in the molten pool temperature and phase composition. The forming process is highly complex and prone to random defects, which in turn affect the microstructure and overall properties of the parts. In recent years, monitoring and quality analysis methods for powder bed melting have received increasing attention. Utilizing LPBF process monitoring technology to perceive forming process information, combined with intelligent prediction methods to anticipate forming defects, allows for rapid preliminary quality assessment during the forming process, enabling timely process adjustments and ensuring forming quality.

[0004] Existing laser powder bed fusion (LPBF) quality analysis methods, when predicting internal defects and formability of parts based on molten pool radiation data, all employ supervised learning methods similar to convolutional neural networks. First, process data is collected, then manually labeled to create a dataset, and finally, a model is trained. The effectiveness of the model's predictions largely depends on the quality of the dataset; a decline in dataset quality significantly impacts prediction effectiveness. However, existing LPBF quality analysis methods typically use high-speed cameras to monitor the melting state of the metal powder during the LPBF process, observing spatter and powder erosion phenomena. Due to the prohibitive cost of high-speed cameras and other hardware, it is impossible to deploy as many high-speed cameras as possible, thus failing to comprehensively collect molten pool radiation information during the LPBF process. This ultimately leads to a decrease in the effectiveness of predicting internal defects and formability of parts. Summary of the Invention

[0005] The technical problem to be solved by this utility model is to provide a molten pool radiation information acquisition device and a laser powder bed melting equipment.

[0006] To solve the above-mentioned technical problems, the present invention adopts the following technical solution:

[0007] A molten pool radiation information acquisition device is used to acquire molten pool radiation information during laser powder bed melting processing. The molten pool radiation information acquisition device includes: a spatial molten pool radiation acquisition unit, which is disposed on the upper top of the forming chamber and is used to acquire spatial molten pool radiation information of one or more wavelengths of each processing layer; and a coaxial optical path molten pool radiation acquisition unit, which is disposed in the laser processing optical path and is used to acquire coaxial optical path molten pool radiation information of one or more wavelengths of each processing layer.

[0008] Preferably, the coaxial optical path molten pool radiation acquisition unit includes any one or any combination of a visible light radiation monitoring subunit, a near-infrared radiation monitoring subunit, a colorimetric thermometry subunit, a laser reflection monitoring subunit, and an infrared radiation monitoring subunit.

[0009] Preferably, the visible light radiation monitoring subunit includes a first semi-transparent mirror, a first focusing filter group, and a visible light radiation sensor. The first semi-transparent mirror can reflect radiation in the 400nm-750nm band and transmit radiation in other bands. The first focusing filter group is used to focus and combine the radiation in the 400nm-750nm band and transmit it to the visible light radiation sensor. The visible light radiation sensor is used to collect radiation in the 400nm-750nm band.

[0010] Preferably, the near-infrared radiation monitoring subunit includes a second semi-transparent mirror, a second focusing filter group, and a near-infrared radiation sensor. The second semi-transparent mirror can reflect radiation in the 750nm-900nm band and transmit radiation in other bands. The second focusing filter group is used to focus and combine the radiation in the 750nm-900nm band and transmit it to the near-infrared radiation sensor. The near-infrared radiation sensor is used to collect radiation in the 750nm-900nm band.

[0011] Preferably, the colorimetric temperature measurement subunit includes a third semi-transparent mirror, a third focusing filter group, and a colorimetric temperature measurement sensor. The third semi-transparent mirror can reflect radiation in the 900nm-950nm band and transmit radiation in other bands. The third focusing filter group is used to focus and combine the radiation in the 900nm-950nm band and transmit it to the colorimetric temperature measurement sensor. The colorimetric temperature measurement sensor is used to collect radiation in the 900nm-950nm band.

[0012] Preferably, the laser reflection monitoring subunit includes a fourth semi-transparent mirror, a fourth focusing filter group, and a laser reflection light sensor. The fourth semi-transparent mirror can reflect radiation in the 1030nm-1080nm band and transmit radiation in other bands. The fourth focusing filter group is used to focus and combine the radiation in the 1030nm-1080nm band and transmit it to the laser reflection light sensor. The laser reflection light sensor is used to collect radiation in the 1030nm-1080nm band.

[0013] Preferably, the infrared radiation monitoring subunit includes a reflector, a fifth focusing filter group, and an infrared radiation sensor. The reflector can reflect radiation in the 1200nm band or higher. The fifth focusing filter group is used to focus and combine the radiation in the 1200nm band or higher and transmit it to the infrared radiation sensor. The infrared radiation sensor is used to collect radiation in the 1200nm band or higher.

[0014] Preferably, the spatial molten pool radiation acquisition unit and the coaxial optical path molten pool radiation acquisition unit are respectively connected to the computer via signal acquisition cards.

[0015] Preferably, the space molten pool radiation acquisition unit includes any one or any combination of visible light radiation sensor, near-infrared radiation sensor, colorimetric temperature sensor, laser reflection light sensor, and infrared radiation sensor.

[0016] A laser powder bed melting device includes the aforementioned molten pool radiation information acquisition device.

[0017] The beneficial technical effects of this utility model are as follows: The above-mentioned molten pool radiation information acquisition device includes a spatial molten pool radiation acquisition unit and a coaxial optical path molten pool radiation acquisition unit. By using the spatial molten pool radiation acquisition unit and the coaxial optical path molten pool radiation acquisition unit, spatial molten pool radiation information transmitted through the internal space of the forming cavity and coaxial optical path molten pool radiation information transmitted in the opposite direction through the laser processing optical path can be acquired respectively. This allows for a more comprehensive acquisition of molten pool radiation information during the laser powder bed melting process. Using the molten pool radiation information acquired by the molten pool radiation information acquisition device as the raw data for laser powder bed melting quality analysis can improve the effectiveness of predicting internal defects and forming performance of parts. Attached Figure Description

[0018] Figure 1 This is a schematic diagram of the structure of the laser powder bed melting equipment of this utility model;

[0019] Figure 2 This is a schematic diagram of the process for analyzing the melting quality of laser powder bed based on the molten pool radiation information collected by the molten pool radiation information acquisition device according to this utility model.

[0020] Explanation of reference numerals in the attached figures:

[0021] 1-Forming chamber, 2-Powder, 3-Powder spreading mechanism, 4-Feeding mechanism, 5-Forming platform, 6-Forming part, 7-Laser, 8-Laser beam, 9-Dialect mirror, 10-Laser deflection and focusing system, 11-Coaxial optical path molten pool radiation, 12-Space molten pool radiation, 13-Space molten pool radiation acquisition unit, 14-Signal acquisition card, 15-Computer, 100-Coaxial optical path molten pool radiation acquisition unit, 201-First semi-transparent and semi-reflective mirror, 202-First focusing filter Mirror group, 203-visible light radiation sensor, 301-second semi-transparent mirror, 302-second focusing filter group, 303-near-infrared radiation sensor, 401-third semi-transparent mirror, 402-third focusing filter group, 403-colorimetric temperature sensor, 501-fourth semi-transparent mirror, 502-fourth focusing filter group, 503-laser reflected light sensor, 601-reflector, 6021-fifth focusing filter group, 603-infrared radiation sensor. Detailed Implementation

[0022] To enable those skilled in the art to more clearly understand the purpose, technical solution and advantages of this utility model, the present utility model will be further described below in conjunction with the accompanying drawings and embodiments.

[0023] This invention provides a laser powder bed melting device, which includes a melt pool radiation information acquisition device for collecting melt pool radiation information during the laser powder bed melting process.

[0024] like Figure 1 As shown, in one embodiment of this utility model, the molten pool radiation information acquisition device includes a spatial molten pool radiation acquisition unit 13 and a coaxial optical path molten pool radiation acquisition unit 100. The spatial molten pool radiation acquisition unit 13 is disposed on the upper top of the forming chamber 1 and is used to acquire spatial molten pool radiation information of one or more wavelengths of each processing layer. The coaxial optical path molten pool radiation acquisition unit 100 is disposed in the laser processing optical path and is used to acquire coaxial optical path molten pool radiation information of one or more wavelengths of each processing layer. The spatial molten pool radiation acquisition unit 13 and the coaxial optical path molten pool radiation acquisition unit 100 are respectively connected to a computer 15 through a signal acquisition card 14 to communicate and upload the acquired spatial molten pool radiation information and coaxial optical path molten pool radiation information to the computer 15.

[0025] In this embodiment, the coaxial optical path molten pool radiation acquisition unit 100 includes a visible light radiation monitoring subunit, a near-infrared radiation monitoring subunit, a colorimetric thermometry subunit, a laser reflection monitoring subunit, and an infrared radiation monitoring subunit. In other embodiments, the coaxial optical path molten pool radiation acquisition unit 100 may also include any one or any combination of the visible light radiation monitoring subunit, near-infrared radiation monitoring subunit, colorimetric thermometry subunit, laser reflection monitoring subunit, and infrared radiation monitoring subunit.

[0026] The visible light radiation monitoring subunit includes a first semi-transparent mirror 201, a first focusing filter group 202, and a visible light radiation sensor 203. The first semi-transparent mirror 201 can reflect radiation in the 400nm-750nm band and transmit radiation in other bands. The first focusing filter group 202 is used to focus and combine the radiation in the 400nm-750nm band and transmit it to the visible light radiation sensor 203. The visible light radiation sensor 203 is used to collect the radiation in the 400nm-750nm band for in-situ monitoring of the state information of the metal plume and plasma cloud generated during the laser powder bed melting process.

[0027] The near-infrared radiation monitoring subunit includes a second semi-transparent mirror 301, a second focusing filter group 302, and a near-infrared radiation sensor 303. The second semi-transparent mirror 301 can reflect radiation in the 750nm-900nm band and transmit radiation in other bands. The second focusing filter group 302 is used to focus and combine the radiation in the 750nm-900nm band and transmit it to the near-infrared radiation sensor 303. The near-infrared radiation sensor 303 is used to collect radiation in the 750nm-900nm band for in-situ monitoring of the state information of plasma cloud and molten pool thermal radiation generated during laser powder bed melting process, and can also be used to reflect the melting depth.

[0028] The colorimetric temperature measurement subunit includes a third semi-transparent mirror 401, a third focusing filter group 402, and a colorimetric temperature sensor 403. The third semi-transparent mirror 401 can reflect radiation in the 900nm-950nm band and transmit radiation in other bands. The third focusing filter group 402 is used to focus and combine the radiation in the 900nm-950nm band and transmit it to the colorimetric temperature sensor. The colorimetric temperature sensor 403 is used to collect radiation in the 900nm-950nm band for in-situ measurement of the temperature change of the molten pool during laser powder bed melting processing.

[0029] The laser reflection monitoring subunit includes a fourth semi-transparent mirror 501, a fourth focusing filter group 502, and a laser reflection light sensor 503. The fourth semi-transparent mirror 501 can reflect radiation in the 1030nm-1080nm band and transmit radiation in other bands. The fourth focusing filter group 502 is used to focus and combine the radiation in the 1030nm-1080nm band and transmit it to the laser reflection light sensor 503. The laser reflection light sensor 503 is used to collect radiation in the 1030nm-1080nm band to monitor the reflected laser formed by the unabsorbed laser when the laser interacts with the powder, thereby reflecting the laser defocusing state and the changes in roughness and thickness of the processed surface during the laser powder bed melting process.

[0030] The infrared radiation monitoring subunit includes a reflector 601, a fifth focusing filter group 602, and an infrared radiation sensor 603. The reflector 601 can reflect radiation in the wavelength band greater than or equal to 1200nm. The fifth focusing filter group 602 is used to focus and combine the radiation in the wavelength band greater than or equal to 1200nm and transmit it to the infrared radiation sensor 603. The infrared radiation sensor 603 is used to collect radiation in the wavelength band greater than or equal to 1200nm to monitor the thermal information of the molten pool surface and surrounding area, such as molten pool, plume, and spatter, during the laser powder bed melting process.

[0031] The space molten pool radiation acquisition unit 13 includes any one or any combination of visible light radiation sensors, near-infrared radiation sensors, colorimetric temperature sensors, laser reflection sensors, and infrared radiation sensors. In specific implementations, if it is necessary to monitor the space molten pool radiation of a certain wavelength band, one of the following sensors can be selected and installed on the top of the forming chamber 1; if it is necessary to monitor the space molten pool radiation of several wavelength bands, several of the following sensors can be selected and distributed on the top of the forming chamber 1.

[0032] The laser powder bed melting equipment of this invention utilizes a melt pool radiation information acquisition device to collect melt pool radiation information during the laser powder bed melting process. The specific process is as follows:

[0033] During the printing process, the forming platform 5 in the forming chamber 1 descends by one layer thickness. The feeding mechanism 4 provides one layer thickness of powder 2, and then the powder spreading mechanism 3 provides one layer thickness of powder to the forming platform through movement. Then, the laser 7 emits a laser beam 8, which passes through the dichroic mirror 9 and the laser deflection and focusing system 10 to reach the focal plane of the forming platform 5, i.e., the surface of the formed part 6. The laser interacts with the powder to form a molten pool, which generates molten pool radiation. The molten pool radiation information acquisition device can collect molten pool radiation information through two pathways: one is that the spatial molten pool radiation 12 generated by the molten pool is freely transmitted to the spatial molten pool radiation acquisition unit 13, and is collected by the sensor inside the spatial molten pool radiation acquisition unit 13; the other is that the coaxial optical path molten pool radiation 11 generated by the molten pool is continuously reflected by the laser deflection and focusing system 10 and the dichroic mirror 9 and transmitted to each subunit of the coaxial optical path molten pool radiation acquisition unit 100, and is collected by each subunit of the coaxial optical path molten pool radiation acquisition unit 100. When collecting molten pool radiation information, the spatial molten pool radiation acquisition unit 13 and the coaxial optical path molten pool radiation acquisition unit 100 are used simultaneously to collect spatial molten pool radiation information of one or more bands and coaxial optical path molten pool radiation information of one or more bands.

[0034] The molten pool radiation information collected by the molten pool radiation information acquisition device is transmitted to the signal acquisition card 14, and then uploaded to the computer 15 through the signal acquisition card 14, which is then used as the raw data for the subsequent laser powder bed melt quality analysis.

[0035] like Figure 2 As shown, in one embodiment of this utility model, the computer 15 performs laser powder bed melting quality analysis based on the molten pool radiation information collected by the molten pool radiation information acquisition device, including steps S10 to S40:

[0036] S10. Obtain the molten pool radiation information corresponding to the target processing layer and perform filtering and noise reduction processing.

[0037] Laser powder bed fusion printing typically processes thousands of layers into a single part. For rapid evaluation, a target processing layer can be selected, and the molten pool radiation information corresponding to that layer can be used as raw data for in-situ calculation and analysis. The target processing layer can be selected using the following strategies: randomly selecting any n processing layers as the target processing layer; or using the processing risk layer determined through evaluation as the target processing layer, where the processing risk layer is obtained through technical evaluation (including personnel experience evaluation or computational simulation evaluation). Of course, in some embodiments where the timeliness of the evaluation is not critical, all processing layers of the part can also be used as the target processing layer.

[0038] After selecting the target processing layer, the molten pool radiation information corresponding to the target processing layer is obtained from the collected molten pool radiation information of each processing layer and then filtered and denoised. The filtering and denoising methods used include, but are not limited to, time-domain filtering and denoising methods, frequency-domain filtering and denoising methods, time-frequency domain integrated filtering and denoising methods, and machine learning denoising methods.

[0039] S20. Extract the time / frequency domain features of the molten pool radiation information corresponding to the target processing layer one melt channel at a time.

[0040] First, the molten pool radiation information corresponding to each target processing layer after filtering and noise reduction is segmented and numbered using feature process identifiers, laser switches, and position vectors to form an index relationship of "number - feature - molten pool - intensity signal".

[0041] Then, for the molten pool radiation information corresponding to each target processing layer after segmentation and numbering, the time / frequency domain features corresponding to each molten channel are extracted one by one. In this embodiment of the present invention, the time / frequency domain features extracted in this step include 16 time domain features p1-p16 and 12 frequency domain features p17-p28, as shown in Table 1. Among them, the 16 time domain features include 10 dimensional features and 6 dimensionless features. The 10 dimensional features are mean, maximum, minimum, peak-to-peak value, median, variance, standard deviation, mean absolute deviation, root mean square, and root mean square amplitude, which mainly reflect the changes in the signal amplitude and energy of the molten pool radiation. The 6 dimensionless features are skewness, kurtosis, peak factor, waveform factor, impulse factor, and margin factor, which mainly reflect the distribution of the molten pool radiation signal in the time domain. Frequency domain feature p17 reflects the magnitude of the radiant energy of the molten pool in the frequency domain. Frequency domain features p18-p20, p22, and p26-p28 characterize the degree of dispersion or concentration of the spectrum. Frequency domain features p21 and p23-p25 reflect the changes in the position of the main frequency band.

[0042]

[0043]

[0044] Table 1: Definitions of time-domain features and frequency-domain features extracted by this utility model

[0045] Where x(n) is the time-domain signal, n = 1, 2, ..., N; N is the total number of samples of any radiated signal on each melting channel. s(k) is the signal spectrum, k = 1, 2, ..., K; K is the number of spectral lines of any radiated signal on each melting channel. k It is the frequency value of the kth spectral line.

[0046] S30. Based on the extracted time / frequency domain features, different unsupervised learning anomaly detection algorithms are used to analyze and solve whether anomalies have occurred in the melt channel.

[0047] Because the causes and manifestations of abnormal melt channels during the LPBF process are often very complex, and single algorithm models all have a certain degree of singularity, with different algorithms having their own advantages and disadvantages, no single algorithm can provide the optimal solution to the problem. Existing research has shown that multi-classifier combinations perform better than single classifiers, and multi-classifier combinations have been used in computer vision and fault diagnosis of rotating machinery.

[0048] This invention analyzes and solves the problem of whether anomalies have occurred in the melt flow by using different unsupervised learning anomaly detection algorithms based on the extracted time / frequency domain features. Then, the solutions of different algorithms are merged according to certain principles to obtain the optimal solution to the problem.

[0049] This invention can employ different unsupervised learning-based anomaly detection algorithms to analyze and solve the problem of whether anomalies have occurred in the melt flow. As shown in Table 2, the main unsupervised learning-based anomaly detection algorithms include: ABOD and COPOD based on probabilistic models, PCA based on linear models, KNN, HBOS, LOF, and CBLOF based on nearest neighbor models, IFOres, FB, and LODA based on ensemble methods, and AutoEncoder and VAE based on neural networks.

[0050]

[0051] Table 2: Anomaly Detection Algorithms Based on Unsupervised Learning

[0052] S40. Merge the solution results of different unsupervised learning anomaly detection algorithms, calculate the performance index, and use the performance index to quantitatively evaluate the processing quality.

[0053] After step S30, n different solutions can be obtained, denoted as O. n (X), O n (X) is the solution result of the nth anomaly detection algorithm model, representing the number of abnormal melt channels predicted by the nth anomaly detection algorithm model, where n = 1, 2, 3, ... n. X is the input analysis data, representing the time / frequency domain characteristics of each melt channel within the target processing layer.

[0054] This invention utilizes n different anomaly detection algorithm models to predict the number of abnormal melt channels in the target processing layer, obtaining n different prediction results (solution results). Then, the solution results from different algorithms are merged according to certain principles to obtain the final number of abnormal melt channels, MCOT. Since the averaging method is the simplest and most efficient multi-classifier combination strategy, this embodiment of the invention chooses the averaging method as the merging strategy for the solution results of multiple different anomaly detection algorithms. That is, the mean of the solution results from each different anomaly detection algorithm is taken to obtain the final number of abnormal melt channels, MCOT.

[0055] MCOT=Mean(O1(X),O2(X),O3(X),…,O n (X)).

[0056] In other embodiments of this utility model, extreme value method, weighted average method, weighted extreme value method, etc. can also be used as a merging strategy for the solution results of multiple different anomaly detection algorithms, so as to calculate the final number of abnormal melt channels (MCOT).

[0057] It is known that the more normal melt channels there are, the better the printing quality, and vice versa. Based on this principle, this invention proposes a method for calculating a performance index to measure quality. Furthermore, since more abnormal melt channels result in worse quality, the performance index pp should be expressed as the reciprocal of MCOT. Therefore, the performance index pp can be calculated using the following formula:

[0058]

[0059] The molten pool radiation information acquisition device of this invention includes a spatial molten pool radiation acquisition unit and a coaxial optical path molten pool radiation acquisition unit. By utilizing the spatial molten pool radiation acquisition unit and the coaxial optical path molten pool radiation acquisition unit, spatial molten pool radiation information transmitted through the internal space of the forming cavity and coaxial optical path molten pool radiation information transmitted in the reverse direction through the laser processing optical path can be acquired respectively. This allows for more comprehensive acquisition of molten pool radiation information during the laser powder bed melting process. Using the molten pool radiation information acquired by the molten pool radiation information acquisition device as the raw data for laser powder bed melting quality analysis can improve the effectiveness of predicting internal defects and forming performance of parts.

[0060] The above description is merely a preferred embodiment of the present utility model and is not intended to limit the present utility model in any way. Those skilled in the art can make various equivalent changes and improvements based on the above embodiments. All equivalent changes or modifications made within the scope of the claims should fall within the protection scope of the present utility model.

Claims

1. A molten pool radiation information acquisition device for acquiring molten pool radiation information in a laser powder bed fusion process, characterized in that, The molten pool radiation information acquisition device comprises: a spatial molten pool radiation acquisition unit arranged at the upper top of the forming chamber and used for acquiring spatial molten pool radiation information of multiple wave bands of each processing layer; a coaxial light path molten pool radiation acquisition unit arranged in a laser processing light path and used for acquiring coaxial light path molten pool radiation information of multiple wave bands of each processing layer; The coaxial light path molten pool radiation acquisition unit comprises any combination of a visible light radiation monitoring subunit, a near-infrared radiation monitoring subunit, a colorimetric temperature measurement subunit, a laser reflection monitoring subunit, and an infrared radiation monitoring subunit.

2. The molten bath radiant information acquisition device of claim 1, wherein, The visible light radiation monitoring subunit comprises a first semi-transparent half mirror, a first focusing filter lens group, and a visible light radiation sensor, the first semi-transparent half mirror can reflect radiation of 400-750 nm wave band and transmit radiation of other wave bands, the first focusing filter lens group is used for focusing and combining the radiation of 400-750 nm wave band and transmitting it to the visible light radiation sensor, and the visible light radiation sensor is used for acquiring the radiation of 400-750 nm wave band.

3. The molten bath radiant information acquisition device of claim 2, wherein, The near-infrared radiation monitoring subunit comprises a second semi-transparent half mirror, a second focusing filter lens group, and a near-infrared radiation sensor, the second semi-transparent half mirror can reflect radiation of 750-900 nm wave band and transmit radiation of other wave bands, the second focusing filter lens group is used for focusing and combining the radiation of 750-900 nm wave band and transmitting it to the near-infrared radiation sensor, and the near-infrared radiation sensor is used for acquiring the radiation of 750-900 nm wave band.

4. The molten bath radiant information acquisition device of claim 3, wherein, The colorimetric temperature measurement subunit comprises a third semi-transparent half mirror, a third focusing filter lens group, and a colorimetric temperature measurement sensor, the third semi-transparent half mirror can reflect radiation of 900-950 nm wave band and transmit radiation of other wave bands, the third focusing filter lens group is used for focusing and combining the radiation of 900-950 nm wave band and transmitting it to the colorimetric temperature measurement sensor, and the colorimetric temperature measurement sensor is used for acquiring the radiation of 900-950 nm wave band.

5. The molten bath radiant information acquisition device of claim 4, wherein, The laser reflection monitoring subunit comprises a fourth semi-transparent half mirror, a fourth focusing filter lens group, and a laser reflection light sensor, the fourth semi-transparent half mirror can reflect radiation of 1030-1080 nm wave band and transmit radiation of other wave bands, the fourth focusing filter lens group is used for focusing and combining the radiation of 1030-1080 nm wave band and transmitting it to the laser reflection light sensor, and the laser reflection light sensor is used for acquiring the radiation of 1030-1080 nm wave band.

6. The molten bath radiant information acquisition device of claim 5, wherein, The infrared radiation monitoring subunit comprises a mirror, a fifth focusing filter lens set and an infrared radiation sensor, the mirror is capable of reflecting radiation of a wavelength of 1200nm or above, the fifth focusing filter lens set is used for focusing and combining processing of radiation of a wavelength of 1200nm or above and transmitting the radiation to the infrared radiation sensor, and the infrared radiation sensor is used for collecting radiation of a wavelength of 1200nm or above.

7. The molten bath radiant information acquisition device of claim 1, wherein, The space molten pool radiation acquisition unit and the coaxial light path molten pool radiation acquisition unit are connected to a computer through signal acquisition cards for communication.

8. The molten bath radiation information acquisition apparatus according to any one of claims 1 to 7, wherein The space molten pool radiation acquisition unit comprises any combination of a visible light radiation sensor, a near-infrared radiation sensor, a colorimetric temperature sensor, a laser reflected light sensor and an infrared radiation sensor.

9. A laser powder bed fusion apparatus, characterized in that, The molten pool radiation information acquisition device comprises the molten pool radiation information acquisition device according to any one of claims 1-8.

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