3D printing real-time monitoring system

Abstract

The invention relates to a 3D printing real-time monitoring system, and the system comprises a monitoring light source which is used for emitting a monitoring light beam; the light splitting assembly is used for receiving the monitoring light beam and splitting the monitoring light beam into reference light and monitoring light; the converging lens assembly is used for transmitting the monitoring light to the bottom of the trough, the monitoring light scattered from the bottom of the trough serves as information light and returns to the light splitting assembly along the original path, and the light splitting assembly reflects the information light so that the information light and the reference light can be propagated in the same direction and interfere with each other in front of a monitoring camera; and the monitoring camera is used for acquiring interference signals along the reference light and the information light and transmitting the acquired interference signals to a computer, and the computer analyzes the interference signals through an algorithm to obtain a monitoring result. By means of the 3D printing monitoring method and device, the problem that the monitoring effect is affected due to the fact that the 3D printing process cannot be effectively monitored due to the influence of the glare phenomenon is solved, and monitoring of the 3D printing object is achieved.

Description

Technical Field

[0001] The present application relates to the field of 3D printing technology, and in particular to a 3D printing real-time monitoring system. Background Art

[0002] Digital Light Processing (DLP) mainly uses a projector to solidify photosensitive polymer liquid layer by layer to create a 3D printed object. DLP-3D printing technology is based on a digital micromirror device chip. When a high-brightness projection light is incident on the bottom of the resin tank through the lens, the resin will solidify, but a light spot will also be generated. This light spot is called glare. However, the glare phenomenon will affect the monitoring of DLP-3D printers. The light spot will cover the information of the 3D printed object when monitoring the 3D printer, making it impossible to detect the 3D printing process.

[0003] At present, the monitoring method for DLP-3D printing system is to adjust the relative position of the monitoring camera and the projector in the printer to reduce glare. However, the projection light source of the DLP-3D printing system needs to be projected onto the resin surface through glass and release film, and the monitoring camera also needs to be projected through glass to obtain the resin molding surface, which is still affected by the glare reflected by the glass, so it is impossible to effectively monitor the DLP-3D printing process, thus affecting the monitoring effect. Summary of the invention

[0004] The embodiment of the present application provides a 3D printing real-time monitoring system to at least solve the problem of poor monitoring effect caused by glare in the related art.

[0005] In a first aspect, an embodiment of the present application provides a 3D printing real-time monitoring system, the monitoring system is used to cooperate with a 3D printing system, the 3D printing system includes a material tank and a curing light source, and the monitoring system includes:

[0006] A monitoring light source, used for emitting a monitoring light beam;

[0007] A beam splitting component, used for dividing the monitoring light beam into a reference light and a monitoring light;

[0008] The converging lens assembly is used to transmit the monitoring light to the bottom of the material tank and obtain the information light scattered by the 3D printing target part. The information light returns to the light splitting assembly along the original path so that the information light and the reference light propagate in the same direction.

[0009] The monitoring camera is used to obtain the interference signal of the reference light and the information light as the imaging data source of the monitoring image.

[0010] In one embodiment, the light splitting component includes: a first light splitting prism, a redirecting mirror set and a second light splitting prism:

[0011] The first beam splitter prism is arranged on the optical path of the monitoring beam, and is used to split the monitoring beam into an initial reference beam and a monitoring beam;

[0012] The redirecting mirror group is arranged on the optical path of the initial reference light, and is used to change the propagation direction of the initial reference light so as to transmit it to the second beam splitter prism;

[0013] The second beam splitter prism is arranged between the first beam splitter prism and the converging lens assembly, and is located on the optical path of the initial reference light, the monitoring light, and the reflected monitoring light, and is arranged corresponding to the monitoring camera. The second beam splitter prism is specifically configured as follows:

[0014] The monitoring light is transmitted to the converging lens assembly,

[0015] After the initial reference light is transmitted, the reference light directed to the monitoring camera is obtained.

[0016] The information light is reflected to obtain information light directed to the monitoring camera.

[0017] In one embodiment, the redirecting mirror assembly comprises: a first reflector and a second reflector,

[0018] a first reflecting mirror, used to change the propagation direction of the initial reference light so as to reflect the initial reference light to the second reflecting mirror,

[0019] The second reflecting mirror is used to change the propagation direction of the initial reference light and reflect the initial reference to the second beam splitter prism.

[0020] In one embodiment, the system further comprises:

[0021] A first collimating lens is disposed between the first beam splitter prism and the second beam splitter prism and is located on the optical path of the monitoring light; and / or

[0022] A second collimating lens is disposed between the first reflector and the second reflector and is located on the optical path of the initial reference light; and / or

[0023] The third collimating lens is arranged before the first beam splitter prism and toward the monitoring light source, and is used for collimating the monitoring light beam.

[0024] In one embodiment, the converging lens assembly comprises: a first condensing lens and a second condensing lens arranged in sequence along the propagation direction of the monitoring light,

[0025] A first condensing lens, used for receiving the monitoring light and expanding the monitoring light;

[0026] The second condenser lens is used to receive and converge the expanded monitoring light so that the converged monitoring light matches the size of the 3D printing target part, wherein the radius of the second condenser lens is greater than the radius of the first condenser lens.

[0027] In one embodiment, the converging lens assembly further comprises:

[0028] The first dichroic mirror is located on the optical paths of the monitoring light and the curing light beam emitted by the curing light source, so that the monitoring light is transmitted to the material slot, and the curing light beam is reflected and transmitted to the material slot.

[0029] In one embodiment, an OCT detection device may be added to the 3D printing real-time monitoring system to improve the real-time monitoring function, including:

[0030] An OCT light source is arranged toward the first beam splitter prism and is used to emit an OCT detection beam toward the first beam splitter prism, so that the OCT detection beam is divided into an OCT initial reference light and a detection light, the OCT initial reference light is in the same direction as the initial reference light, and the detection light is in the same direction as the monitoring light;

[0031] A reference arm assembly is disposed between the first beam splitter prism and the second beam splitter prism and is placed along the optical path of the OCT initial reference light, and is used to reflect the OCT initial reference light transmitted by the first beam splitter prism to obtain the OCT reference light, and return the OCT reference light to the first beam splitter prism, and is also used to adjust the optical path of the OCT initial reference light and the OCT reference light;

[0032] The sample arm assembly is located between the second beam splitter prism and the material tank, and is used to transmit the detection light to the 3D printed target part, and return the OCT information light scattered by the 3D printed target part to the first beam splitter prism, and the OCT information light and the OCT reference light interfere with each other in the first beam splitter prism;

[0033] The spectrometer is used to obtain interference signals along the OCT reference light and the OCT information light to serve as the imaging data source of the three-dimensional monitoring image.

[0034] In one embodiment, the reference arm assembly includes: a third condenser lens, a reference dichroic mirror, and a fourth condenser lens;

[0035] The third condenser lens is used to converge the OCT reference light;

[0036] The reference dichroic mirror is used to reflect the converged OCT reference light and transmit the initial reference light to the second beam splitter prism;

[0037] The fourth condensing lens is arranged on a side of the reference dichroic mirror opposite to the third condensing lens, and is used for converging the initial reference light and transmitting the initial reference light to the second beam splitting prism.

[0038] In one embodiment, the sample arm assembly comprises:

[0039] Scanning component, the scanning component includes a two-dimensional galvanometer and a liquid lens. The liquid lens determines the target layer of the 3D object to be scanned by changing the focal length, and the two-dimensional galvanometer scans the target layer with detection light by rotating;

[0040] Redirection assembly, the redirection assembly includes:

[0041] The second dichroic mirror is used to reflect the detection light to the scanning component and transmit the monitoring light to the converging lens component.

[0042] The third dichroic mirror is used to receive the detection light transmitted by the scanning component, reflect the detection light to the material tank, and transmit the monitoring light to the converging lens component.

[0043] In one embodiment, verifying the monitoring effectiveness of the 3D printing real-time monitoring system includes:

[0044] Based on the light field of the 3D printing real-time monitoring system, a physical model of a single-layer 3D printing target part is constructed;

[0045] Based on the physical model and the fast Fourier algorithm, the ideal interference image of the physical model in the ideal scene and the defect interference image in the scene with the preset defect are obtained;

[0046] Based on the ideal interference image and the defect interference image, the defect hologram and the ideal hologram are obtained through a preset algorithm, and the defect hologram and the ideal hologram are subtracted to obtain a subtraction result. If the subtraction result includes image information, it indicates that the 3D printing real-time monitoring system is effective.

[0047] A 3D printing real-time monitoring system provided by an embodiment of the present application has at least the following technical effects.

[0048] The monitoring light beam is split by the beam splitter component to obtain reference light and monitoring light. The monitoring light is further emitted to the 3D printing system through the converging lens component, and reflects the information light carrying the 3D printing target part. The information light is then transmitted to the beam splitter component through the converging lens component for beam splitting to obtain information light consistent with the propagation direction of the reference light, so that the information light and the reference light interfere with each other, and the monitoring camera obtains the phase information of the light in the interference image, thereby avoiding the collection of the amplitude information of the light, so that the monitoring camera will not produce glare when monitoring the 3D printing target part, and can obtain complete information of the 3D printing target part.

[0049] Details of one or more embodiments of the present application are set forth in the following drawings and description to make other features, objects, and advantages of the present application more readily apparent. BRIEF DESCRIPTION OF THE DRAWINGS

[0050] The drawings described herein are used to provide a further understanding of the present application and constitute a part of the present application. The illustrative embodiments of the present application and their descriptions are used to explain the present application and do not constitute an improper limitation on the present application. In the drawings:

[0051] Figure 1is a schematic diagram of a 3D printing real-time monitoring system according to an exemplary embodiment;

[0052] Figure 2 is a schematic diagram of a light splitting component of a 3D printing real-time monitoring system according to an exemplary embodiment;

[0053] Figure 3 is a schematic diagram of a light splitting component of a 3D printing real-time monitoring system according to another exemplary embodiment;

[0054] Figure 4 is a schematic diagram of a 3D printing real-time monitoring system according to another exemplary embodiment;

[0055] Figure 5 is a schematic diagram of a physical model of a single-layer 3D printing target part according to an exemplary embodiment;

[0056] Figure 6 is a schematic diagram of an ideal interference image of a single-layer 3D printing target part according to an exemplary embodiment;

[0057] Figure 7 is a schematic diagram of an unprinted single-layer 3D printing target part according to an exemplary embodiment;

[0058] Figure 8 is a schematic diagram of a single-layer 3D printing target part with printing defects according to an exemplary embodiment;

[0059] Fig. 9 is a schematic diagram of a first defect image of an unprinted single-layer 3D printing target part according to an exemplary embodiment;

[0060] Fig.10 is a schematic diagram of a second defect image of a single-layer 3D printing target part according to an exemplary embodiment;

[0061] Fig.11 is a schematic diagram showing a third defect image according to an exemplary embodiment.

[0062] In the above drawings, the meanings of the reference numerals are as follows:

[0063] 101. 3D printing system, 1011. curing light source, 1012. printing platform, 1013. material tank;

[0064] 102, monitoring light source; 103, monitoring camera; 104, first beam splitter prism; 105, second beam splitter prism; 106, second collimating lens; 107, first collimating lens; 108, first reflector; 109, second reflector; 110, first condensing lens; 111, second condensing lens; 112, first dichroic mirror;

[0065] 201, OTC light source; 202, spectrometer; 203, fifth condenser lens;

[0066] 204, reference arm assembly, 2041, third condenser lens, 2042, reference dichroic mirror, 2043, fourth condenser lens;

[0067] 205, a second dichroic mirror; 206, a third reflecting mirror;

[0068] 207, scanning assembly, 2071, liquid lens, 2072, two-dimensional galvanometer; 208, third dichroic mirror; 209, fourth dichroic mirror; 210, third collimating lens; 211, third beam splitter prism;

[0069] 301, light splitting assembly, 3011, redirecting mirror assembly; 302, converging lens assembly; 303, sample arm assembly; 304, redirecting assembly;

[0070] 400, monitoring beam, 401, initial reference light, 402, reference light, 403, monitoring light, 404, information light;

[0071] 500, OCT detection beam, 501, OCT initial reference light, 502, OCT reference light, 503 detection light, 504, OCT information light;

[0072] 800, defects due to uncured light; 900, defects due to undercured light. DETAILED DESCRIPTION

[0073] In order to make the purpose, technical solutions and advantages of the present application clearer, the present application is described and illustrated below in conjunction with the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present application and are not intended to limit the present application. Based on the embodiments provided in the present application, all other embodiments obtained by ordinary technicians in the field without making creative work are within the scope of protection of the present application.

[0074] Obviously, the drawings described below are only some examples or embodiments of the present application. For ordinary technicians in this field, the present application can also be applied to other similar scenarios based on these drawings without creative work. In addition, it can also be understood that although the efforts made in this development process may be complicated and lengthy, for ordinary technicians in this field related to the content disclosed in this application, some changes in design, manufacturing or production based on the technical content disclosed in this application are just conventional technical means, and should not be understood as insufficient content disclosed in this application.

[0075] Reference to "embodiments" in this application means that a particular feature, structure, or characteristic described in conjunction with the embodiments may be included in at least one embodiment of the present application. The appearance of the phrase in various locations in the specification does not necessarily refer to the same embodiment, nor is it an independent or alternative embodiment that is mutually exclusive with other embodiments. It is explicitly and implicitly understood by those of ordinary skill in the art that the embodiments described in this application may be combined with other embodiments without conflict.

[0076] Unless otherwise defined, the technical terms or scientific terms involved in this application should be understood by people with ordinary skills in the technical field to which this application belongs. The words "one", "a", "a", "the" and the like involved in this application do not indicate a quantitative limitation, and may represent the singular or plural. The terms "include", "comprise", "have" and any of their variations involved in this application are intended to cover non-exclusive inclusions; for example, a process, method, system, product or device that includes a series of steps or modules (units) is not limited to the listed steps or units, but may also include steps or units that are not listed, or may also include other steps or units inherent to these processes, methods, products or devices. The words "connect", "connected", "coupled" and the like involved in this application are not limited to physical or mechanical connections, but may include electrical connections, whether direct or indirect. The "multiple" involved in this application refers to two or more. "And / or" describes the association relationship of associated objects, indicating that there may be three relationships, for example, "A and / or B" can represent: A exists alone, A and B exist at the same time, and B exists alone. The character " / " generally indicates that the objects before and after are in an "or" relationship. The terms "first", "second", "third", etc. involved in this application are only used to distinguish similar objects and do not represent a specific ordering of the objects.

[0077] In the top-pull 3D printing system, taking the DLP-3D printing system as an example, the DLP-3D printing system includes a material tank that can hold resin, which is used to hold resin that can be cured after being irradiated with ultraviolet light of a specific wavelength. The DLP imaging system is placed below the material tank, and its imaging surface is located at the bottom of the material tank. Through energy and graphic control, a thin layer of resin with a certain thickness and shape can be cured each time. The cross-sectional shape of this layer of resin is exactly the same as that of the printed three-dimensional entity. A lifting mechanism is set above the material tank. After each cross-sectional exposure is completed, it is lifted up to a certain height, and the height is consistent with the layer thickness, so that the solid resin that has been cured is separated from the bottom of the material tank and bonded to the lifting plate or the last formed resin layer, and a three-dimensional entity is generated by exposing and lifting layer by layer.

[0078] In the process of forming a three-dimensional entity, the entire formation process needs to be monitored to ensure the accuracy of the three-dimensional entity. However, in the process of monitoring the 3D printing system, there will be a light spot when the monitoring light is projected on the material tank, that is, the glare phenomenon, which easily hinders the monitoring of 3D printing and cannot monitor the target object of 3D printing in real time.

[0079] Based on the above situation, an embodiment of the present application provides a 3D printing real-time monitoring system.

[0080] In a first aspect, the present application provides a 3D printing real-time monitoring system. Figure 1 is a schematic diagram of a 3D printing real-time monitoring system according to an exemplary embodiment. Figure 1 As shown, the 3D printing real-time monitoring system includes: a monitoring light source 102 , a light splitting component 301 , a converging lens component 302 and a monitoring camera 103 .

[0081] The monitoring light source 102 is used to emit a monitoring light beam 400. Preferably, the monitoring light source 102 is a laser light source. The laser light source is combined with other components in the system and can realize the collection of sample information based on the principle of light interference.

[0082] The light splitting component 301 is used to split the monitoring light beam 400 into a reference light 402 and a monitoring light 403 .

[0083] The converging lens assembly 302 is used to transmit the monitoring light 403 to the bottom of the material tank 1013, and obtain the information light 404 scattered by the 3D printing target part and return it to the light splitting assembly 301 along the original path, so that the information light 404 and the reference light 402 propagate in the same direction and interfere with each other in front of the monitoring camera 103;

[0084] The monitoring camera 103 is used to obtain the interference signal of the reference light 402 and the information light 404, and transmit the interference signal to the computer as the data source of the monitoring image imaging. Based on the principle of light interference, the reference light 402 and the information light 404 interfere with each other at the second beam splitter prism 105, and the monitoring camera 103 collects the interference signal. The monitoring camera 103 transmits the collected interference signal to the computer, and the computer analyzes the interference signal through an algorithm to obtain the monitoring result for evaluating the printing effect of the 3D printing target part.

[0085] In this way, the monitoring light beam 400 is split by the light splitting component 301 to obtain the reference light 402 and the monitoring light 403 with the same frequency, light intensity and phase difference. The monitoring light 403 is transmitted to the printing platform 1012 in the 3D printing system through the converging lens component 302 to obtain the information light 404 carrying the scattered 3D printing target part. The information light 404 is then transmitted to the light splitting component 301 through the converging lens component 302 to obtain the information light 404 with the same propagation direction as the reference light 402, so that the information light 404 and the reference light 402 are optically interfered, and the phase information of the information light 404 is obtained, thereby avoiding the collection of the amplitude information of the light, so that the monitoring camera 103 will not produce glare when monitoring the 3D printing target part, and the complete information of the 3D printing target part can be obtained.

[0086] Regarding the implementation of the light splitting component 301, continue to refer to Figure 1 The beam splitting component 301 includes a first beam splitting prism 104, a redirecting lens group 3011 and a second beam splitting prism 105. The first beam splitting prism 104 is disposed on the optical path of the monitoring beam 400, and is used to split the monitoring beam 400 into an initial reference beam 401 and a monitoring beam 403.

[0087] Redirection mirror group 3011 is arranged on the optical path of initial reference light 401, and is used to change the propagation direction of initial reference light 401, and passes through second beam splitter prism 105, wherein redirection mirror group 3011 includes first reflector 108 and second reflector 109. Initial reference light 401 is reflected by first reflector 108 to change the propagation direction of initial reference light 401 once, and then reflected by second reflector 109 for the second time to change the propagation direction of initial reference light 401. At this time, the propagation direction of initial reference light 401 reflected by second reflector 109 is the propagation direction of reference light 402.

[0088] The second beam splitter prism 105 is disposed between the first beam splitter prism 104 and the converging lens assembly 302, located on the optical paths of the initial reference light 401, the monitoring light 403 and the information light 404, and is disposed corresponding to the monitoring camera 103. The second beam splitter prism 105 is specifically configured as follows:

[0089] The monitoring light 403 is transmitted through the second beam splitter prism 105 and the converging component 302 to the printing platform 1012, and then returns to the second beam splitter prism 105 along the original path carrying the information light 404 scattered by the printing target part, propagates in the same direction as the reference light 402 transmitted through the second beam splitter prism 105 by the initial reference light 401, and interferes at the second beam splitter prism 105, and the interference signal is received by the monitoring camera 103.

[0090] The monitoring light beam 400 is divided into an initial reference light 401 and a monitoring light 403 by the first beam splitter prism 104 in the beam splitter assembly 301. The initial reference light 401 is reflected by the first reflector 108 and the second reflector 109 to change the propagation direction, and becomes the reference light 402 after passing through the second beam splitter prism 105; the monitoring light 403 is transmitted through the second beam splitter prism 105 and the converging lens assembly 302 to the material slot 1013 of the 3D printing system 101, and the information light 404 carrying the scattered 3D printing target part is obtained. The information light 404 returns to the second beam splitter prism 105 along the original path, so that the information light 404 and the reference light 402 propagate in the same direction and interfere at the second beam splitter prism 105, and the interference signal is obtained by the monitoring camera 103. Since the information light 404 and the reference light 402 have the same frequency, vibration direction, and phase difference, the two interfere with each other, so that the monitoring camera 103 obtains the interference signal of the light.

[0091] The above-mentioned light splitting component 301 further includes a first collimating lens 107, a second collimating lens 106 and a third collimating lens 210, which satisfy the following configuration:

[0092] The first collimating lens 107 is disposed between the first beam splitter prism 104 and the second beam splitter prism 105 and is located on the optical path of the monitoring light 403. And / or

[0093] The second collimating lens 106 is disposed between the first reflecting mirror 108 and the second reflecting mirror 109 and is located on the optical path of the initial reference light 401. And / or

[0094] The third collimating lens 210 is disposed before the first beam splitter prism 104 and toward the monitoring light source 102 , and is used for collimating the monitoring light beam 400 .

[0095] The first collimating lens 107, the second collimating lens 106 and the third collimating lens 210 can be set according to specific applications. Through the above collimating lenses, the light diffused by refraction, reflection, etc. can be collimated again to prevent the light from being too dispersed to affect subsequent signal collection.

[0096] Regarding the implementation of the converging lens assembly 302, optionally, a first condensing lens 110 and a second condensing lens 111 are sequentially arranged along the propagation direction of the monitoring light 403. The first condensing lens 110 is used to receive the monitoring light 403 and expand the monitoring light 403. The second condensing lens 111 is used to receive and converge the expanded monitoring light 403 so that the converged monitoring light 403 is the same size as the 3D printing target part, wherein the radius of the second condensing lens 111 is greater than the radius of the first condensing lens 110.

[0097] In addition, the converging lens assembly 302 further includes a first dichroic mirror 112. The first dichroic mirror 112 is located on the optical paths of the monitoring light 403 and the curing light beam emitted by the curing light source 1011, so that the monitoring light 403 is transmitted to the material tank 1013 and the curing light beam is reflected to the material tank 1013.

[0098] By utilizing the principle that the first dichroic mirror 112 can transmit and reflect light of different wavelengths, the monitoring light 403 is transmitted to the material tank 1013 , while the curing light beam is reflected to the material tank 1013 .

[0099] In the embodiment of the present application, the specific positional relationship between the monitoring camera 103 and the light splitting component 301 is not specifically limited, except that Figure 1 The following are two optional examples.

[0100] In one example, Figure 2 is a schematic diagram of a light splitting component of a 3D printing real-time monitoring system according to an exemplary embodiment. Figure 2 As shown, the monitoring camera 103 is located on the left side of the monitoring optical path (different from Figure 1 As shown, the monitoring camera 103 is located on the right side of the monitoring optical path), and the second beam splitter prism 105 is used to reflect the information light 404 to obtain the information light 404 in the direction of the monitoring camera, which is different from Figure 1 The information light 404 of the monitoring camera 103 on the right side of the monitoring optical path shown. A first reflector 108 is provided to change the propagation direction of the initial reference light 401. A third beam splitter prism 211 is provided in front of the monitoring camera 103, and the third beam splitter prism 211 is used to transmit the information light 404 and reflect the initial reference light 401 to obtain the reference light 402 in the same direction as the information light 404. Therefore, the information light 404 is reflected by the second beam splitter prism 105 and interferes with the reference light 402 at the third beam splitter prism 211, so that the monitoring camera 103 collects the interference signal.

[0101] In one example, Figure 3 is a schematic diagram of a light splitting component of a 3D printing real-time monitoring system according to another exemplary embodiment. Figure 3 As shown, the monitoring camera 103 is located on the left side of the monitoring optical path and above the third beam splitter prism 211, which is different from Figure 1 As shown, the monitoring camera 103 is located on the right side of the monitoring optical path. The second beam splitter prism 105 is used to reflect the information light 404 to the left side of the monitoring optical path. Figure 1The second beam splitter prism 105 shown is used to reflect the information light 404 to the monitoring camera 103 on the right side of the monitoring optical path. A first reflector 108 is provided to change the propagation direction of the initial reference light 401. A third beam splitter prism 211 is provided in front of the monitoring camera 103. The third beam splitter prism 211 is used to reflect the information light 404 and transmit the initial reference light 401 to obtain the information light 404 with the same direction as the reference light 402, which is different from Figure 2 The third beam splitter prism 211 is shown. Therefore, the information light 404 is reflected by the second beam splitter prism 105 and interferes with the reference light 402 at the third beam splitter prism 211, so that the monitoring camera collects the interference signal.

[0102] The monitoring light source 102 can only collect single-layer information for the 3D printing target part, but cannot collect multi-layer information. Therefore, only single-layer information can be displayed on the monitoring camera 103. For example, the 3D printing system 101 has printed four layers of the 3D printing target part, and the monitoring light 403 emitted by the monitoring light source 102 can only collect the current layer information as required. Since the target part printed by the 3D printing system 101 is a 3D object, the target part will be stretched as the height is continuously stacked, but the monitoring camera 103 cannot monitor the stretching phenomenon of the 3D printing target part, resulting in a deviation between the monitored information and the actual object. In another embodiment, an OCT device is introduced to solve this problem.

[0103] Figure 4 is a schematic diagram of a 3D printing real-time monitoring system according to another exemplary embodiment. Figure 4 As shown, the 3D printing real-time monitoring system also includes an OCT detection device. The OCT detection device includes: an OCT light source 201, a reference arm assembly 204, a sample arm assembly 303 and a spectrometer 202.

[0104] The OCT light source 201 is disposed toward the first beam splitter prism 104, and is used to emit an OCT detection beam 500 toward the first beam splitter prism 104. The first beam splitter prism 104 splits the OCT detection beam 500 into an OCT initial reference light 501 and a detection light 503. The OCT initial reference light 501 is in the same direction as the initial reference light 401, and the detection light 503 is in the same direction as the monitoring light 403. It should be noted that the OCT light source 201 is a broadband light source.

[0105] The detection beam 500 is focused on the first beam splitter prism 104 by the fifth condenser lens 203 , and the first beam splitter prism 104 splits the OCT detection beam 500 into an OCT initial reference beam 501 and a detection beam 503 .

[0106] The reference arm assembly 204 is disposed between the first beam splitter prism 104 and the second beam splitter prism 105 and is placed along the optical path of the reference light 402. It is used to reflect the OCT initial reference light 501 to form the OCT reference light 502, and reflect the OCT reference light 502 to the spectrometer 202. The optical path of the OCT reference light 502 and the OCT initial reference light 501 can be adjusted.

[0107] The reference arm assembly 204 includes a third condensing lens 2041 and a reference dichroic mirror 2042. The third condensing lens 2041 is used to condense the OCT initial reference light 501. The reference dichroic mirror 2042 is used to reflect the condensed OCT initial reference light 501 and transmit the initial reference light 401 to the second beam splitter prism 105.

[0108] Optionally, the reference arm assembly 204 is adjusted in an automatic and manual manner. That is, by moving left and right according to the monitoring signal in the spectrometer 202 and based on the operator's experience, the sum of the optical paths of the OCT initial reference light 501 and the OCT reference light 502 is adjusted, so that after the OCT detection beam 500 is split by the first beam splitter prism 104, the sum of the optical paths of the OCT initial reference light 501 and the OCT reference light 502, and the sum of the optical paths of the detection light 503 and the OCT information light 504 remain consistent. Alternatively, the reference arm assembly 204 is automatically adjusted through an algorithm to achieve the sum of the optical paths of the OCT initial reference light 501 and the OCT reference light 502, and the sum of the optical paths of the detection light 503 and the OCT information light 504, and the two optical paths remain consistent.

[0109] It should be noted that after the OCT initial reference light 501 is reflected by the reference dichroic mirror 2042, the OCT reference light 502 is obtained. After the OCT reference light 502 is reflected by the second reflector 109 and the first reflector 108, the propagation direction is changed and transmitted to the first beam splitter prism 104, so that the propagation direction of the OCT reference light 502 is consistent with that of the OCT information light 504, and the OCT reference light 502 and the OCT information light 504 perform optical interference at the first beam splitter prism 104.

[0110] In addition, the reference arm assembly 204 further includes a fourth condensing lens 2043. The initial reference light 401 is transmitted to the second beam splitter prism 105 via the reference dichroic mirror 2042 and the fourth condensing lens 2043 to better interfere with the light.

[0111] Although reference arm assembly 204 can move left and right to control the optical path of OCT reference light 502 and OCT initial reference light 501 , initial reference light 401 is transmitted to second beam splitter prism 105 via reference dichroic mirror 2042 . Therefore, reference arm assembly 204 does not affect the optical path of initial reference light 401 .

[0112] The sample arm assembly 303 is located between the second beam splitter prism 105 and the material trough 1013. The detection light 503 passes through the sample arm assembly 303 to the 3D printing target part, and the OCT information light 504 scattered by the sample arm assembly 303 and the second beam splitter prism 105 returns to the first beam splitter prism 104. The OCT information light 504 propagates in the same direction as the OCT reference light 502 and interferes at the first beam splitter prism 104.

[0113] The sample arm assembly 303 includes a scanning assembly 207 and a redirection assembly 304, and the two components satisfy the following configuration: the scanning assembly 207 includes a two-dimensional galvanometer 2072 and a liquid lens 2071, the liquid lens 2071 determines the target layer of the 3D object to be scanned by changing the focal length, and the two-dimensional galvanometer 2072 rotates to allow the detection light 503 to scan the target layer.

[0114] The specific steps for deep scanning of 3D printed target parts include:

[0115] The curvature of the lens in the liquid lens 2071 is adjusted by voltage, thereby adjusting the focal length. When the detection light 503 passes through the liquid lens 2071, the detection light 503 will obtain optical information on the printed layers at different depths based on different focal lengths. The two-dimensional galvanometer 2072 can rotate and vibrate around its axis, thereby achieving two-dimensional scanning of the printed layer in the X-axis and Y-axis directions with the printed layer of the 3D printed target part as the horizontal plane.

[0116] That is, when the detection light 503 passes through the liquid lens 2071, the focus of the detection light 503 on the 3D printed target part will be changed. The printed layer where the focus is located is the target layer that the two-dimensional galvanometer 2072 needs to scan. The two-dimensional galvanometer 2072 obtains the optical information of the target layer by scanning the target layer. Since the change of the focal length of the liquid lens 2071 causes the two-dimensional galvanometer 2072 to scan target layers of different depths, the light of different depths scattered back by the 3D printed target part forms the OCT information light 504, thereby completing the depth scanning of the 3D printed target part.

[0117] The redirection assembly 304 includes:

[0118] The second dichroic mirror 205 is used to reflect the detection light 503 to the scanning assembly 207 and transmit the monitoring light 403 to the first condensing lens 110 in the converging lens assembly 302 .

[0119] The third dichroic mirror 208 is used for receiving the detection light 503 transmitted by the scanning assembly 207 and reflecting it to the material tank 1013 , and transmitting the monitoring light 403 to the second condensing lens 111 in the converging lens assembly 302 .

[0120] Both the monitoring light 403 and the detection light 503 need to be irradiated on the material tank 1013 in the end to obtain the information light 404 and the OCT information light 504 carrying the information of the 3D printing target part. The OCT device is arranged along the optical path of the monitoring light 403. In order to prevent the detection light 503 from affecting the monitoring light 403, after the detection light 503 passes through the light splitting component 301, the propagation direction of the detection light 503 needs to be changed so that the detection light 503 is transmitted to the material tank 1013 through the sample arm component 303. Therefore, the second dichroic mirror 205 is used to change the propagation direction of the detection light 503 so that it is different from the propagation direction of the monitoring light 403, and the third dichroic mirror 208 is used to reflect the detection light 503 to the material tank 1013.

[0121] Therefore, the second dichroic mirror 205 and the third dichroic mirror 208 are sequentially placed along the propagation direction of the monitoring light 403. After the detection light 503 changes its propagation direction through the second dichroic mirror 205, a third reflector 206 is placed to reflect the detection light 503 to the sample arm assembly 303. The detection light 503 passes through the sample arm assembly 303 and the third dichroic mirror 208, and is transmitted to the material tank 1013.

[0122] The spectrometer 202 is used to obtain interference signals along the OCT reference light 502 and the OCT information light 504. The spectrometer 202 transmits the collected interference signals to the computer, and the computer obtains a three-dimensional image of the 3D printing target part through an algorithm and uses it as a three-dimensional monitoring image.

[0123] In addition, the fourth dichroic mirror 209 is disposed between the spectrometer 202 and the first beam splitter prism 104 , and is disposed along the propagation direction of the OCT information light 504 and the OCT reference light 502 , so that the OCT information light 504 and the OCT reference light 502 are transmitted to the spectrometer 202 , and reflects the monitoring beam 400 to the first beam splitter prism 104 .

[0124] The OCT reference light 502 and the OCT information light 504 perform optical interference at the first beam splitter prism 104 and are transmitted to the spectrometer 202 via the fourth dichroic mirror 209 to obtain an optical interference signal.

[0125] It should be noted that the interference signal of the single layer displayed on the monitoring camera 103 and the interference signal displayed on the spectrometer 202 are displayed synchronously, that is, the 3D printed target part is printing the third layer. At this time, the monitoring camera 103 captures the information of the third layer, and the spectrometer 202 captures the information of the first to third layers of the 3D printed target part.

[0126] In summary, the 3D printing real-time monitoring system provided in the embodiment of the present application, through interference between reference light and information light, and obtaining light phase information based on the interference signal of light, thereby avoiding glare phenomenon and realizing real-time monitoring of the target layer of the 3D printed target part. Based on the OCT device, the problem of only being able to monitor a single layer in real time is further solved. The 3D printed target part is deeply scanned based on the scanning component, and the interference signal of the OCT reference light and the OCT information light is obtained and transmitted to the computer. The computer analyzes the interference signal through an algorithm to obtain a three-dimensional monitoring image of the 3D printed target part, thereby realizing three-dimensional monitoring of the 3D printed target part.

[0127] Based on the above 3D printing real-time monitoring system, a method for verifying the feasibility of the 3D printing real-time monitoring system is provided. The method for verifying the feasibility of the 3D printing real-time monitoring system includes the following steps:

[0128] Step S101: construct a physical model of a single-layer 3D printing target part based on the light field of the 3D printing real-time monitoring system.

[0129] Figure 5 is a schematic diagram of a physical model of a single-layer 3D printing target part according to an exemplary embodiment. Figure 5 As shown, before printing, the 3D printing system slices the 3D model of the object to be printed into hundreds of thin layers, and then the 3D printing system prints the thin layers layer by layer and stacks these thin layers to print the desired object. Therefore, a physical model of a single-layer 3D target part is constructed by matlab, wherein the constructed physical model includes the shape of the single layer and the thickness of the single layer. It should be noted that the thickness of the single layer is determined by the intensity of the curing light source, and the greater the intensity of the curing light source, the greater the thickness.

[0130] Based on the shape of the 3D printing target part and the intensity of the curing light source in the light field of the 3D printing real-time monitoring system, a physical model of a single-layer 3D printing target part is constructed, which simulates the object printed in the 3D printing system. It is also the object to be monitored by the 3D printing real-time monitoring system.

[0131] Step S102: Based on the physical model and the fast Fourier algorithm, an ideal interference image of the physical model in an ideal scene and a defect interference image in a scene with a preset defect are obtained.

[0132] Figure 6 is a schematic diagram of a schematic diagram of an ideal interference image of a single-layer 3D printing target part according to an exemplary embodiment, such as Figure 6 As shown, in matlab, according to a single-layer 3D printed target part, an interference image of the single-layer 3D printed target part is obtained based on the D-FFT algorithm.

[0133] The scenarios of preset defects include single-layer 3D printing target parts that are not printed and single-layer 3D printing target parts that are printed with defects, where defects include uncured defects and undercured defects. Uncured defects are when the curing light source in the 3D printing system is irradiated to the material tank, the corresponding solid structure is not formed. Undercured defects are when the curing light source in the 3D printing system is irradiated to the material tank, the solid structure formed does not reach the target thickness.

[0134] Figure 7 is a schematic diagram of an unprinted single-layer 3D printing target part according to an exemplary embodiment. Figure 7 As shown, in matlab, according to the unprinted single-layer 3D printing target part, the interference image of the unprinted single-layer 3D printing target part is obtained based on the D-FFT algorithm.

[0135] Figure 8 is a schematic diagram of a single-layer 3D printing target part with printing defects according to an exemplary embodiment. Figure 8 As shown, if a single-layer 3D printed target part has a defect 800 of not being photocured, a gap will appear, thereby presenting a color consistent with the background. If a single-layer 3D printed target part has a defect 900 of under-photocuring, a gap will appear, but the color presented is different from the background, but not the same as the background color. In matlab, based on the printing of a single-layer 3D printed target part with defects, an interference image of the defects of the printed single-layer 3D printed target part is obtained based on the D-FFT algorithm.

[0136] Step S103, based on the ideal interference image and the defect interference image, a defect hologram and an ideal hologram are obtained by a preset algorithm, and the defect hologram and the ideal hologram are subtracted to obtain a subtraction result. If the subtraction result includes image information, it indicates that the 3D printing real-time monitoring system is effective.

[0137] Based on the ideal interference image and S-FFT algorithm, an ideal hologram of a single-layer 3D printed target part is obtained, wherein the ideal hologram is a hologram of a single-layer 3D printed target part completely printed by a 3D printing system. The ideal hologram includes amplitude and phase information about the single-layer 3D printed target part.

[0138] Based on the interference image of the unprinted single-layer 3D printing target part and the S-FFT algorithm, the first defect hologram of the unprinted single-layer 3D printing is obtained. That is, it simulates the situation that when a single-layer 3D printing target part is printed during the printing process of the 3D printing system, the layer is not printed successfully.

[0139] Based on the interference image of the defective single-layer 3D printing target part and the S-FFT algorithm, a second defect hologram about the defective single-layer 3D printing is obtained. That is, it simulates the situation in which the single-layer 3D printing target part is printed unsuccessfully or only partially printed during the printing process of the 3D printing system.

[0140] Fig. 9 is a schematic diagram of a first defect image of an unprinted single-layer 3D printing target part according to an exemplary embodiment. Fig. 9 As shown, the first defect hologram is subtracted from the ideal hologram to obtain the first defect image. There are interference fringes in the first defect image, wherein the interference fringes represent the change in the morphology of the 3D printing target part. If interference fringes appear, it means that there is a defect at the position corresponding to the interference fringes. Among them, the darker the color of the interference fringes, the greater the deviation between the actual printing result and the ideal printing result, which indicates that the 3D printing real-time monitoring system is effective.

[0141] Fig.10 is a schematic diagram of a second defect image of a single-layer 3D printing target part according to an exemplary embodiment. Fig.10 As shown, the second defect hologram is subtracted from the ideal hologram to obtain the second defect image. In the second interference image, the interference fringe images of the corresponding uncured defects and undercured defects can be obtained, but the corresponding defects cannot be clearly seen in the second interference image. Therefore, the second defect image is divided from the ideal hologram to obtain the third defect image. Fig.11 is a schematic diagram of a third defect image according to an exemplary embodiment. Fig.11 As shown in the figure, a clear defect can be obtained. That is, by observing the position of the defect in the figure, the position of the defect on the 3D printing target part can be determined. According to the position of the defect on the 3D printing target part, it is shown that the 3D printing real-time monitoring system is effective.

[0142] The first defect image, the second defect image and the third defect image in the above description simulate the process of the monitoring camera obtaining the monitoring image in the 3D printing real-time monitoring system. The monitoring image can be used to directly observe whether there are defects in the 3D printing target part, so as to complete the monitoring of the 3D printing target part, thereby demonstrating the effectiveness of the 3D printing real-time monitoring system.

[0143] Through the above-mentioned simulation of the monitoring process in the 3D printing real-time monitoring system based on MATLAB, the corresponding first defect image, second defect image and third defect image are obtained based on the existence of defects, and the corresponding defects can be monitored, thereby verifying the feasibility of the 3D printing real-time monitoring system.

[0144] The technical features of the above-described embodiments may be arbitrarily combined. To make the description concise, not all possible combinations of the technical features in the above-described 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.

[0145] The above-mentioned embodiments only express several implementation methods of the present application, and the descriptions thereof are relatively specific and detailed, but they cannot be understood as limiting the scope of the invention patent. It should be pointed out that, for a person of ordinary skill in the art, several variations and improvements can be made without departing from the concept of the present application, and these all belong to the protection scope of the present application. Therefore, the protection scope of the patent of the present application shall be subject to the attached claims.

Claims

1. A 3D printing real-time monitoring system, characterized in that: The monitoring system is used to cooperate with a 3D printing system, the 3D printing system includes a material tank and a curing light source, and the monitoring system includes: A monitoring light source, used for emitting a monitoring light beam; A light splitting component, used for splitting the monitoring light beam into a reference light and a monitoring light; A converging lens assembly is used to transmit the monitoring light to the bottom of the material tank and obtain information light scattered by the 3D printing target part, and the information light returns to the light splitting assembly along the original path, so that the information light and the reference light propagate in the same direction; The monitoring camera is used to obtain the interference signal between the reference light and the information light as an imaging data source of the monitoring image.

2. The 3D printing real-time monitoring system according to claim 1, characterized in that: The light splitting component comprises: a first light splitting prism, a redirecting mirror set and a second light splitting prism: The first beam splitter prism is arranged on the optical path of the monitoring light beam, and is used to split the monitoring light beam into an initial reference light and the monitoring light; The redirecting mirror group is arranged on the optical path of the initial reference light, and is used to change the propagation direction of the initial reference light so as to transmit to the second beam splitter prism; The second beam splitter prism is disposed between the first beam splitter prism and the converging lens assembly, is located on the optical path of the initial reference light, the monitoring light and the reflected monitoring light, and is disposed corresponding to the monitoring camera. The second beam splitter prism is specifically configured as follows: The monitoring light is transmitted to the converging lens assembly, The reference light emitted to the monitoring camera is obtained after the initial reference light is transmitted. The information light is reflected to obtain the information light directed toward the monitoring camera.

3. The 3D printing real-time monitoring system according to claim 2, characterized in that: The redirecting mirror assembly comprises: a first reflector and a second reflector, The first reflector is used to change the propagation direction of the initial reference light to reflect the initial reference light to the second reflector, The second reflector is used to change the propagation direction of the initial reference light and reflect the initial reference light to the second beam splitter prism.

4. The 3D printing real-time monitoring system according to claim 3, characterized in that: The system further comprises: A first collimating lens is disposed between the first beam splitter prism and the second beam splitter prism and is located on the optical path of the monitoring light; and / or A second collimating lens is disposed between the first reflector and the second reflector and is located on the optical path of the initial reference light; and / or The third collimating lens is arranged before the first beam splitter prism and toward the monitoring light source, and is used for collimating the monitoring light beam.

5. The 3D printing real-time monitoring system according to claim 1, characterized in that: The converging lens assembly comprises: a first condensing lens and a second condensing lens arranged in sequence along the propagation direction of the monitoring light, The first condenser lens is used to receive the monitoring light and expand the monitoring light; The second condenser lens is used to receive and converge the expanded monitoring light so that the converged monitoring light matches the size of the 3D printing target part, wherein the radius of the second condenser lens is greater than the radius of the first condenser lens.

6. The 3D printing real-time monitoring system according to claim 4, characterized in that: The converging lens assembly also includes: The first dichroic mirror is located on the optical paths of the monitoring light and the curing light beam emitted by the curing light source, so that the monitoring light is transmitted to the material slot, and the curing light beam is reflected and transmitted to the material slot.

7. The 3D printing real-time monitoring system according to claim 2, characterized in that: An OCT detection device can be added to the system to improve real-time monitoring functions, including: An OCT light source is arranged toward the first beam splitter prism, and is used to emit an OCT detection beam toward the first beam splitter prism, so that the OCT detection beam is divided into an OCT initial reference light and a detection light, the OCT initial reference light is in the same direction as the initial reference light, and the detection light is in the same direction as the monitoring light; a reference arm assembly, disposed between the first beam splitter prism and the second beam splitter prism and placed along the optical path of the OCT initial reference light, for reflecting the OCT initial reference light transmitted by the first beam splitter prism to obtain OCT reference light, and returning the OCT reference light to the first beam splitter prism, and for adjusting the optical path lengths of the OCT initial reference light and the OCT reference light; a sample arm assembly, located between the second beam splitter prism and the material tank, for transmitting the detection light to the 3D printing target part, and returning the OCT information light scattered by the 3D printing target part to the first beam splitter prism, so that the OCT information light and the OCT reference light interfere with each other at the first beam splitter prism; A spectrometer is used to obtain interference signals along the OCT reference light and the OCT information light to serve as an imaging data source for a three-dimensional monitoring image.

8. The 3D printing real-time monitoring system according to claim 6, characterized in that: The reference arm assembly includes: a third condenser lens, a reference dichroic mirror and a fourth condenser lens; The third condensing lens is used to converge the OCT reference light; The reference dichroic mirror is used to reflect the converged OCT reference light and transmit the initial reference light to the second beam splitter prism; The fourth condensing lens is disposed on a side of the reference dichroic mirror opposite to the third condensing lens, and is used for converging the initial reference light and transmitting the initial reference light to the second beam splitting prism.

9. The 3D printing real-time monitoring system according to claim 7, characterized in that: The sample arm assembly comprises: A scanning component, the scanning component includes a two-dimensional galvanometer and a liquid lens, the liquid lens determines the target layer of the 3D object to be scanned by changing the focal length, and the two-dimensional galvanometer rotates to allow the detection light to scan the target layer; A redirection component, the redirection component comprising: a second dichroic mirror, for reflecting the detection light to the scanning assembly and transmitting the monitoring light to the converging lens assembly, The third dichroic mirror is used to receive the detection light transmitted by the scanning component, reflect the detection light to the material tank, and transmit the monitoring light to the converging lens component.

10. A verification method for real-time monitoring of 3D printing, characterized in that: Used to verify the monitoring effectiveness of the 3D printing real-time monitoring system according to any one of claims 1 to 9, comprising: Based on the light field of the 3D printing real-time monitoring system, a physical model of a single-layer 3D printing target part is constructed; Based on the physical model and the fast Fourier algorithm, an ideal interference image of the physical model in an ideal scene and a defect interference image in a scene with a preset defect are obtained; Based on the ideal interference image and the defect interference image, a defect hologram and the ideal hologram are obtained by a preset algorithm, and the defect hologram and the ideal hologram are subtracted to obtain a subtraction result. If the subtraction result includes image information, it indicates that the 3D printing real-time monitoring system is effective.

Images