A method and device for detecting the printing effect quality of a light-curing printing device

Abstract

The present invention discloses a method for detecting the printing effect quality of a light-curing printing device, which obtains the sliced model data corresponding to the printing model, divides the sliced model data into three main parts: the surface layer, the general layer, and the support layer. For any classified sliced layer, each layer includes corresponding 3D printing control parameters. Different light-curing forming schemes for different layers are obtained by controlling the printing control parameters at different positions; for different layers, the planar contour of the support layer printed is respectively detected to determine whether there is a discontinuous phenomenon and / or the surface connection area is uneven, and during the printing process, it is detected whether the step error of the general layer is stable. If it is detected that the step error is less than a preset threshold, the thickness of the general layer is increased to reduce the step error value; or when detecting, only determine whether the surface contour forming defect of the surface layer is obvious. If it is determined that the defect is obvious, the spot size of the laser device is reduced.

Description

Technical Field

[0001] The present invention relates to the technical field of 3D printing equipment, and in particular to a method and device for detecting the printing effect quality of a light-curing printing device. Background Art

[0002] The methods of part processing and forming can be generally divided into two categories in terms of the basic idea. One is the traditional method of gradually removing materials from the whole to finally obtain the finished part, such as traditional turning, milling, drilling, grinding, planing, etc.; the other is from the perspective of discrete addition, adding materials layer by layer to stack the required part, such as various rapid prototyping methods, SLS, LOM, FDM, etc. People have developed various new mechanical processing and forming equipment along these two ideas respectively, or by combining the two ideas, such as electric discharge machining, wire cutting technology, laser cutting, water jet cutting technology, etc. The modern 3D printing technology guided by the additive manufacturing concept has attracted extensive attention from all aspects of society. Different countries and regions have studied it from different angles and developed various 3D printers.

[0003] The light-curing additive manufacturing technology has a fast forming speed and high precision. Its principle is to initiate a cross-linking reaction in a specific area of the liquid photosensitive resin through light of a specific wavelength, complete the curing of the corresponding pattern, and realize the manufacturing of a three-dimensional structure through layer-by-layer stacking. According to the forming method of light curing, the main factors affecting its precision are the precision of the forming optical path system, control precision, and resin forming precision. Therefore, researching measures to improve the light-curing forming precision has become one of the hot topics in the additive manufacturing engineering. The existing research mainly focuses on the influence of the optical path structure on the overall forming precision. However, according to the light-curing forming principle, it is difficult to achieve high forming precision in large-scale forming.

[0004] Therefore, the quality supervision of light-curing printed products has become a top priority. However, the traditional supervision and detection methods require a large amount of manpower, resulting in the inability to meet the needs of a large number of prints. In the prior art, the SLA forming process strategy means that when forming a part, an appropriate forming process mode can be selected according to requirements such as printing precision, printing quality, or printing speed. Classifying it according to the type of process parameters, different process strategies set different default values of process parameter items, so as to obtain different process package contents. By selecting a suitable forming process package, parts with different printing qualities can be obtained.

[0005] At present, the setting items of the forming process parameters of other SLA forming equipment are relatively single. The values of the process parameters are obtained through a large number of experiments. The values of the forming process parameters can only be used on equipment of the same model, and the versatility of the process parameter values is poor, and the controllable adjustment of the forming accuracy cannot be achieved. In order to better meet customer needs and cost control, the SLA forming process parameters are now classified and studied, and different process strategies are formulated to meet the controllable adjustment of printing accuracy, printing speed and printing cost. Correspondingly, how to supervise and detect the printing effect during the controllable adjustment printing process is the problem to be solved by the present invention. Summary of the Invention

[0006] The present invention aims to solve at least one of the technical problems existing in the prior art. To this end, the present invention discloses a method for detecting the printing effect quality of a light-curing printing device, and the detection method includes the following steps:

[0007] S1, obtaining the sliced model data corresponding to the printed model, dividing the sliced model data into three main parts: a surface layer, a general layer and a support layer. For any classified sliced layer, each layer includes corresponding 3D printing control parameters, and different light-curing forming schemes for different layers are obtained by controlling the printing control parameters at different positions;

[0008] S2, for the support layer, perform three-dimensional printing according to the generated light-curing forming scheme. When the printing process reaches the first preset stage, detect the planar contour of the support layer printed, and judge whether there is a discontinuous phenomenon and / or the surface connection area is uneven (i.e., there are lines). If the judgment result is yes, correct the laser scanning speed in the printing control parameters, and ensure the printing effect of the support layer by reducing the laser scanning speed;

[0009] S3, after the printing of the support layer is completed, perform the printing of the general layer. The general layer is the main layer of the 3D printed product. During the printing process, detect whether the staircase error of the general layer is stable. If it is detected that the staircase error is less than the preset threshold, do not modify the printing parameters of the general layer. When the detection result is greater than, re-layer the sliced model data and increase the thickness of the general layer to reduce the staircase error value;

[0010] S4, after the printing of both the support layer and the general layer is completed, perform the printing detection of the surface layer, and cure the surface layer by using a fast-curing scheme, that is, when detecting, only judge whether the surface contour forming defect of the surface layer is obvious. If the defect is judged to be obvious, reduce the spot size of the laser device.

[0011] Furthermore, the 3D printing control parameters are filling parameters, laser parameters and working parameter contents.

[0012] Furthermore, to achieve the reuse of software interface elements, all parameters are classified. When different stereolithography (SLA) forming schemes are selected, the software control system completes the selection of printing schemes for different layers by loading different configuration files.

[0013] Furthermore, in the classification of SLA process parameters, the process parameters that affect the forming quality and printing time are grouped into one item. Different SLA forming schemes are obtained by formulating the content of filling parameters, laser parameters, and working parameters.

[0014] Furthermore, when performing inspections on different layers, edge detection and image processing of the SLA printed product are carried out by using a CCD camera. The grayscale processing of the captured image is performed by using the grayscale histogram equalization method to enhance the image clarity of different layers of the printed product. For the processed image, image noise points are removed by using Gaussian filtering, and the grayscale gradient amplitude and change direction of the image are analyzed through the Gaussian function to determine the position of the local gradient maximum value of the image; the image is processed by using a double-threshold algorithm. The high-threshold algorithm is used to detect the edges of the image, and the low-threshold algorithm is used to connect the edges of the image after high-threshold processing to complete the final image edge detection.

[0015] Furthermore, the local edge points of the image are compared to determine the edge points with the maximum grayscale value, and the rest are set to 0. The double-threshold algorithm is used to process the pseudo-edges contained in the image to identify the contour states of the images of different printed layers.

[0016] The present invention also discloses a printing effect quality detection system based on an SLA printing device. The system includes:

[0017] A layering and scheme selection module, which obtains the sliced model data corresponding to the printing model, divides the sliced model data into three main parts: a surface layer, a general layer, and a support layer. For any classified sliced layer, each layer includes corresponding 3D printing control parameters. Different SLA forming schemes for different layers are obtained by controlling the printing control parameters at different positions.

[0018] A support layer detection module. For the support layer, three-dimensional printing is carried out according to the generated SLA forming scheme. When the printing process reaches the first preset stage, the planar contour of the support layer printing is detected to determine whether there is a discontinuous phenomenon and / or unevenness in the surface connection area (i.e., there are lines). If the judgment result is yes, the laser scanning speed in the printing control parameters is corrected, and the laser scanning speed is reduced to ensure the printing effect of the support layer.

[0019] The general layer detection module performs the printing of the general layer after the printing of the support layer is completed. The general layer is the main layer of the 3D printed product. During the printing process, it detects whether the staircase error of the general layer is stable. If it detects that the staircase error is less than a preset threshold, the printing parameters of the general layer are not modified. When the detection result is greater than the threshold, the sliced model data is re-layered, and the thickness of the general layer is increased to reduce the staircase error value.

[0020] The surface layer detection module performs the printing detection of the surface layer after the printing of both the support layer and the general layer is completed. It cures the surface layer using a rapid curing solution, that is, when detecting, it only judges whether the surface profile forming defects of the surface layer are obvious. If it is judged that the defects are obvious, the spot size of the laser device is reduced.

[0021] Furthermore, the support layer is the bottom layer that provides support for the printed product, and is divided according to the structure of the printed model or according to 20% of the overall layering of the printed model; the surface layer is the layer other than the general layer and the support layer that are the main body of the printed model.

[0022] The present invention also discloses an electronic system, including: a memory, a processor, and a computer program stored on the memory and executable on the processor. When the processor executes the computer program, it implements the steps in the printing effect quality detection method based on the stereolithography printing device.

[0023] The present invention also discloses a computer-readable storage medium, on which a computer program is stored. When the computer program is executed by a processor, it implements the steps in the printing effect quality detection method based on the stereolithography printing device.

[0024] Compared with the prior art, the beneficial effect of the present invention is that for the requirements of the stereolithography 3D printing device in different printing stages of different layers are different. The present invention detects the pain points of stereolithography for different layers, which can greatly improve the printing quality of the finished product and reduce the printing time and detection time. It is not necessary to detect all the detection points for each layer, but to detect the important problems for each layer. Description of the Drawings

[0025] The present invention can be further understood from the following description in conjunction with the drawings. The components in the drawings are not necessarily drawn to scale, but the focus is on showing the principles of the embodiments. In the drawings, the same reference numerals designate corresponding parts in different views.

[0026] Figure 1 is a flowchart of the printing effect quality detection method based on the stereolithography printing device of the present invention. Detailed Embodiments

[0027] The technical solution of the present invention will be described in more detail below in conjunction with the accompanying drawings and embodiments.

[0028] Now, mobile terminals implementing various embodiments of the present invention will be described with reference to the accompanying drawings. In the following description, suffixes such as "module", "component", or "unit" used to denote elements are only for facilitating the description of the present invention, and have no specific meaning in themselves. Therefore, "module" and "component" can be used interchangeably.

[0029] Mobile terminals can be implemented in various forms. For example, the terminals described in the present invention may include mobile terminals such as mobile phones, smart phones, laptop computers, digital broadcast receivers, PDAs (Personal Digital Assistants), PADs (Tablet Computers), PMPs (Portable Multimedia Players), navigation devices, etc., and fixed terminals such as digital TVs, desktop computers, etc. Hereinafter, it is assumed that the terminal is a mobile terminal. However, those skilled in the art will understand that, except for elements specifically for mobile purposes, the configuration according to the embodiments of the present invention can also be applied to fixed-type terminals.

[0030] As Figure 1 shown, a method for detecting the printing effect quality of a light-curing printing device, the detection method comprising the following steps:

[0031] S1. Obtain the sliced model data corresponding to the printing model, divide the sliced model data into three main parts: a surface layer, a general layer, and a support layer. For any classified sliced layer, each layer includes corresponding 3D printing control parameters, and different light-curing forming schemes for different layers are obtained by controlling the printing control parameters at different positions.

[0032] S2. For the support layer, perform three-dimensional printing according to the generated light-curing forming scheme. When the printing process reaches the first preset stage, detect the planar contour of the support layer printing, and determine whether there is a discontinuous phenomenon and / or unevenness in the surface connection area (i.e., there are lines). If the determination result is yes, correct the laser scanning speed in the printing control parameters, and ensure the printing effect of the support layer by reducing the laser scanning speed.

[0033] S3. After the printing of the support layer is completed, perform the printing of the general layer. The general layer is the main layer of the 3D printed product. During the printing process, detect whether the staircase error of the general layer is stable. If it is detected that the staircase error is less than the preset threshold, do not modify the printing parameters of the general layer. If the detection result is greater than, re-layer the sliced model data and increase the thickness of the general layer to reduce the staircase error value.

[0034] S4. After the printing of both the support layer and the general layer is completed, the printing inspection of the surface layer is carried out, and a rapid curing scheme is adopted to cure the surface layer, that is, when detecting, only judge whether the surface profile forming defects of the surface layer are obvious. If it is judged that the defects are obvious, the spot size of the laser device is reduced.

[0035] Furthermore, the 3D printing control parameters are filling parameters, laser parameters and working parameter contents.

[0036] Furthermore, to achieve the reuse of software interface elements, all parameters are classified. When different stereolithography forming schemes are selected, the software control system completes the selection of printing schemes for different layers by loading different configuration files.

[0037] Furthermore, in the classification of stereolithography process parameters, the process parameters that affect the forming quality and printing time are grouped into one item, and different stereolithography forming schemes are obtained by formulating the contents of filling parameters, laser parameters and working parameters.

[0038] Furthermore, when detecting different layers, edge detection and image processing of the stereolithography printed product are carried out by using a CCD camera. The grayscale processing of the captured image is carried out by using the grayscale histogram equalization method to enhance the image clarity of different layers of the printed product. For the processed image, the image noise points are removed by using Gauss filtering, and the grayscale gradient amplitude and change direction of the image are analyzed through the Gauss function to determine the position of the local gradient maximum value of the image; the image is processed by using the double-threshold algorithm, the high-threshold algorithm is used to detect the edge of the image, and the low-threshold algorithm is used to connect the edges of the image after high-threshold processing to complete the final image edge detection.

[0039] Furthermore, the local edge points of the image are compared with each other, and the edge points with the maximum grayscale value are determined, and the rest are set to 0 values. The double-threshold algorithm is used to process the pseudo-edges contained in the image to identify the contour state of the images of different printing layers.

[0040] In this embodiment, the laser power is one of the important factors affecting the printing forming. If the laser power is too small, the laser energy absorbed by the photosensitive resin per unit time cannot meet the basic requirements of curing. Therefore, serious defects such as layer misalignment and layer breakage will occur between adjacent layers of the formed part, resulting in forming failure. If the laser power is too large, after the laser energy absorbed by the photosensitive resin per unit time reaches the curing requirement, the excess laser energy will cause the resin around the spot to cure, increasing the curing area, resulting in a significant decrease in the forming accuracy of the surface of the formed part; in addition, the cured layer absorbs too much laser energy, which is prone to stress and strain, resulting in warping and deformation of the formed layer, affecting the scraping operation of the doctor blade, and even damaging the part.

[0041] Appropriate laser power is the key to printing. The setting of laser power should be determined according to process parameters such as layer thickness and scanning speed. After the model is sliced, the layer thickness has been determined. According to the working principle of the laser scanning system, the laser scanning speed can be adjusted within a certain range, so the laser power is also within a certain range.

[0042] In this embodiment, the conditions that need to be considered to affect the printing effect also include: the laser scanning speed is one of the direct factors that determine the molding efficiency. The higher the scanning speed, the higher the molding efficiency. However, when the laser scanning speed is too high, the time for the laser to act on the surface of the photosensitive resin is too short, which reduces the resin curing effect, and the scanning contour of the slice layer is prone to intermittent phenomenon. Between the scanning lines, the solidified connection area becomes smaller, causing concave stripes to appear in the surface connection area, and more obvious lines to appear in the acute angle area, which leads to a significant decrease in the surface quality of the molded part; at the same time, the switching time of the laser at the jump point is reduced, the output stability is reduced, and the service life of the laser is reduced. If the laser scanning speed is too low, the molding efficiency will be greatly reduced.

[0043] The third point is the influence of layer thickness. When the layer thickness is too small, the step error produced by part slicing is smaller, but the cumulative error produced in the molding direction increases, and the molding time of the part will increase exponentially; the thickness of the laser solidified layer is small, and the scraper is easy to scrape the part when performing the scraping action, causing the part support to deform, resulting in the inability to form the primary layer, thus causing printing failure. When the layer thickness is too large, the step error produced by part slicing is more significant, and the surface roughness of the molded part is greater. Therefore, appropriate layer thickness can both improve molding accuracy and shorten printing time.

[0044] At the same time, the spot size directly affects the precision of part molding. When the spot size is too large, the smaller the angle between the contour lines of the scanning trajectory, the more obvious the surface contour molding defects, and the worse the surface quality of the molded parts; when the spot size is too small, the molding effect is better in the acute angle area of ​​the part surface contour scanning line, but the number of spot contour scanning lines increases, the laser scanning time increases, and too many scans at the fine structure of the part can easily cause stress deformation of the part. The spot size has a great influence on the surface quality of the molded parts. Therefore, a variable spot mechanism is configured in the existing SLA molding equipment. In actual molding, the outer contour of the part is usually scanned with a small spot, and the internal contour is filled with a large spot. While improving the molding efficiency, the surface accuracy of the part is guaranteed.

[0045] In this embodiment, in the classification of the process parameters of photocuring, the process parameters that affect the forming quality and printing time are grouped into one item, and different process strategies are obtained by formulating the content of the filling parameters, laser parameters, and working parameters. The formulated process strategies are divided into three types: quality mode, speed mode, and balance mode. Among them, the quality mode mainly focuses on improving the forming accuracy of parts and is suitable for printing parts with fine structures; the speed mode mainly shortens the printing time and is suitable for occasions where the strength requirements of parts are not high; the balance mode is to set multiple process parameters while considering both the forming accuracy and the forming speed. This mode requires a higher level of operation for the forming equipment operators and is mainly applied in the printing of large parts. Considering both the forming accuracy and the forming speed can reduce the processing cost of parts.

[0046] It should also be noted that the term "comprising", "including" or any other variant thereof is intended to cover a non-exclusive inclusion, such that a process, method, commodity or device comprising a series of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such process, method, commodity or device. Without further limitation, an element defined by the statement "comprising an..." does not exclude the presence of additional identical elements in the process, method, commodity or device comprising the said element.

[0047] Those skilled in the art should understand that the embodiments of the present application can be provided as a method, system, or computer program product. Therefore, the present application can take the form of a complete hardware embodiment, a complete software embodiment, or an embodiment combining software and hardware aspects. Moreover, the present application can take the form of a computer program product implemented on one or more computer-usable storage media (including but not limited to disk storage, CD-ROM, optical storage, etc.) containing computer-usable program code.

[0048] Although the present invention has been described above with reference to various embodiments, it should be understood that many changes and modifications can be made without departing from the scope of the present invention. Therefore, it is intended that the above detailed description be considered illustrative rather than restrictive, and it should be understood that the following claims (including all equivalents) are intended to define the spirit and scope of the present invention. These embodiments should be understood as only illustrative of the present invention and not limiting the scope of protection of the present invention. After reading the content described in the present invention, those skilled in the art can make various changes or modifications to the present invention, and these equivalent changes and modifications also fall within the scope defined by the claims of the present invention.

Claims

1. A printing effect quality detection method based on a light-curing printing device, characterized in that, The detection method includes the following steps: S1. Obtain the sliced model data corresponding to the printed model. Divide the sliced model data into three main parts: the surface layer, the general layer, and the support layer. For any classified sliced layer, each layer includes corresponding 3D printing control parameters. By controlling the printing control parameters at different positions, different stereolithography forming schemes for different layers are obtained; S2. For the support layer, perform three-dimensional printing according to the generated stereolithography forming scheme. When the printing process reaches the first preset stage, detect the planar contour of the printed support layer, and determine whether there is a discontinuous phenomenon and / or unevenness in the surface connection area. If the determination result is yes, correct the laser scanning speed in the printing control parameters, and ensure the printing effect of the support layer by reducing the laser scanning speed; S3. After the printing of the support layer is completed, execute the printing of the general layer. The general layer is the main layer of the 3D printed product. During the printing process, detect whether the staircase error of the general layer is stable. If it is detected that the staircase error is less than the preset threshold, do not modify the printing parameters of the general layer. If the detection result is greater, re-layer the sliced model data and increase the thickness of the general layer to reduce the staircase error value; S4. After the printing of both the support layer and the general layer is completed, perform the printing detection of the surface layer. Adopt a rapid curing scheme to cure the surface layer, that is, when detecting, only determine whether the surface contour forming defects of the surface layer are obvious. If the determined defects are obvious, reduce the spot size of the laser device.

2. The printing effect quality detection method based on a light-curing printing device according to claim 1, wherein The 3D printing control parameters are filling parameters, laser parameters, and working parameter contents.

3. The printing effect quality detection method based on a light-curing printing device according to claim 2, characterized in that, To realize the reuse of software interface elements, all parameters are classified. When selecting different stereolithography forming schemes, the software control system completes the selection of the printing schemes for different layers by loading different configuration files.

4. The printing effect quality detection method based on a light-curing printing device according to claim 3, wherein In the classification of the process parameters of stereolithography, the process parameters that affect the forming quality and printing time are grouped into one item, and different stereolithography forming schemes are obtained by formulating the contents of the filling parameters, laser parameters, and working parameters.

5. The printing effect quality detection method based on a photocuring printing device according to claim 1, wherein, When performing the detection of different layers, edge detection and image processing of the stereolithography printed product are carried out by using a CCD camera. The gray processing of the captured image is carried out by using the gray histogram equalization method to enhance the image clarity of different layers of the printed product. For the processed image, the image noise points are removed by using Gaussian filtering, and the gray gradient amplitude and change direction of the image are analyzed through the Gaussian function to determine the position of the local gradient maximum value of the image; the image is processed by using the double-threshold algorithm, the high-threshold algorithm is used to detect the edge of the image, and the low-threshold algorithm is used to connect the edge of the image processed by the high-threshold algorithm to complete the final image edge detection.

6. The printing effect quality detection method based on a light curing printing device according to claim 5, characterized in that Compare the local edge points of the image, determine the edge points with the maximum gray value, and set the rest to 0. The pseudo-edges contained in the image are processed by the double-threshold algorithm to identify the contour state of the images of different printed layers.

7. A printing effect quality detection system based on a light-curing printing device, characterized in that The system includes: Layering and scheme selection module, which obtains the sliced model data corresponding to the printing model, divides the sliced model data into three main parts: the surface layer, the general layer, and the support layer. For any classified sliced layer, each layer includes corresponding 3D printing control parameters, and different stereolithography forming schemes for different layers are obtained by controlling the printing control parameters at different positions; Support layer detection module. For the support layer, three-dimensional printing is performed according to the generated stereolithography forming scheme. When the printing process reaches the first preset stage, the planar contour of the support layer printing is detected to determine whether there is a discontinuous phenomenon and / or the surface connection area is uneven. If the judgment result is yes, the laser scanning speed in the printing control parameters is corrected, and the printing effect of the support layer is ensured by reducing the laser scanning speed; General layer detection module. After the support layer printing is completed, the printing of the general layer is executed. The general layer is the main layer of the 3D printing product. During the printing process, it is detected whether the staircase error of the general layer is stable. If it is detected that the staircase error is less than the preset threshold, the printing parameters of the general layer are not modified. When the detection result is greater than, the sliced model data is re-layered, and the general layer thickness is increased to reduce the staircase error value; Surface layer detection module. After the support layer and the general layer are both printed, the printing detection of the surface layer is performed. The surface layer is cured by using a rapid curing scheme, that is, when detecting, it is only judged whether the surface contour forming defect of the surface layer is obvious. If the defect is judged to be obvious, the spot size of the laser device is reduced.

8. The printing effect quality detection system based on a stereolithography printing device according to claim 7, wherein The support layer is the bottom layer that provides support for the printed product, and is divided according to the structure of the printing model or according to 20% of the overall layering of the printing model; the surface layer is the layer other than the general layer and the support layer that serves as the main body of the printing model.

9. An electronic system, characterized in that, Including: A memory, a processor, and a computer program stored on the memory and executable on the processor. When the processor executes the computer program, the steps in the printing effect quality detection method based on a stereolithography printing device as described in any one of claims 1 to 6 are implemented.

10. A computer-readable storage medium, characterized in that, A computer program is stored on the computer-readable storage medium. When the computer program is executed by the processor, the steps in the printing effect quality detection method based on a stereolithography printing device as described in any one of claims 1 to 6 are implemented.

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