WO2022007423A1

WO2022007423A1 - 3d printing method and 3d printing device

Info

Publication number: WO2022007423A1
Application number: PCT/CN2021/079728
Authority: WO
Inventors: 朱荣付; 刘振亮; 李厚民
Original assignee: 优你造科技(北京)有限公司
Priority date: 2020-07-06
Filing date: 2021-03-09
Publication date: 2022-01-13
Also published as: CN111745959A; CN111745959B

Abstract

The present application relates to a 3D printing method and a 3D printing device. The method comprises: identifying a contour of a model slice image, and dividing the image into a first type area and a second type area, the first type area being an area in the image within a preset range from the contour, and the second type area being an area in the image other than the first type area; and, according to a preset policy, exposing the first type area and the second type area, the exposure of the first type area being less than the exposure of the second type area. The solution provided in the present application can reduce the impact on the slice edge outer side during the 3D printing process.

Description

3D printing method and 3D printing device

technical field

The present application relates to the technical field of 3D printing, and in particular, to a 3D printing method and a 3D printing device.

Background technique

3D printing technology is a kind of rapid prototyping technology, which has important application value in aerospace, medicine, construction and other fields. Print the way to construct objects.

SLA (Stereo lithography Appearance, three-dimensional curing molding method) uses liquid photosensitive resin as raw material. During the printing process, the three-dimensional three-dimensional model will be sliced first, and then blue-violet or ultraviolet light of specific wavelength and intensity is used to irradiate the slices layer by layer, so that the The slices are solidified and cured. When the curing operation of one slice is completed, the lifting table moves the height of one slice in the vertical direction, and then solidifies another slice, so that the layers are superimposed to form a three-dimensional entity.

However, this technique has the following defects: due to the direction of the light and the slice not being completely perpendicular, and the refraction, scattering, and diffuse reflection of the light in the resin, the light will diffuse to the outside of the slice boundary, so that the cured size outside the slice edge increases, and the slice Internal dimensions are reduced.

SUMMARY OF THE INVENTION

In order to overcome the problems existing in the related art, the present application provides a 3D printing slice exposure method, device and equipment, which can reduce the influence of the printing process on the outside of the slice edge and improve the printing accuracy.

A 3D printing method, comprising: recognizing the outline of a model slice image, and dividing the image into a first type area and a second type area; wherein, the first type area is a distance preset from the outline in the image The area within the range; the second type area is the area outside the first type area in the image; the first type area and the second type area are exposed according to the preset strategy, the first type area The exposure amount is less than the exposure amount of the second type area.

The above method further includes: for the determined model slice thickness, preset at least one set of correspondences of the first type of area exposure parameter, the second type of area exposure parameter and the first distance value; and, according to the slice thickness, Determine the first type of area exposure parameter, the second type of area exposure parameter and the first distance value in a set of corresponding relationships to perform resin photocuring of the sliced pattern; wherein, the first type of area is the distance in the image from the The area within the first distance value of the contour.

Alternatively, the above method further includes: obtaining a set of first-type area exposure parameters, second-type area exposure parameters and first distance values input by the user, and performing resin photocuring; wherein the first-type area is the image The middle distance is the area within the first distance value of the contour.

In the above method, the exposure parameters include: exposure intensity and exposure duration; the exposure intensity and exposure duration obtain the exposure amount.

In the above method, the exposure strategy includes:

The first type of area and the second type of area start to be exposed at the same time;

Or, perform exposure of the second type of area after starting the exposure of the first type of area;

Alternatively, the exposure of the first type of area is performed after the exposure of the second type of area is started;

Or, after the exposure of the first type of area is completed, the exposure of the second type of area is performed;

Alternatively, the exposure of the first type of area is performed after the exposure of the second type of area is completed.

In the above method, the exposure intensity of the second type of area exposure is not less than the necessary exposure intensity required to complete the resin photocuring of the slice thickness; the exposure amount of the second type area exposure is not less than the necessary exposure required to complete the resin photocuring of the slice thickness. quantity.

In the above method, the exposure intensity of the first type of area exposure is not greater than the exposure intensity of the second type of area exposure, and is greater than the critical exposure intensity that can cause resin photocuring; the first type of area exposure Necessary exposure required for photocuring of the resin at the thickness of the slice.

Specifically, the exposure intensity of the second type area is the same as that of the first type area, and the exposure duration of the first type area is shorter than that of the second type area; or, the exposure time of the second type area and the first type area is The exposure time is the same, and the exposure intensity of the first type area is less than that of the second type area; or, the exposure time of the second type area is less than the exposure time of the first type area, and the exposure intensity of the first type area is less than that of the second type area. strength.

In the above method, the exposure duration of the first type of area exposure is zero, so that the first type of area is not exposed separately.

In the above method, the exposure light intensity of the first type of area exposure is zero, so that the first type of area is not exposed separately.

In the above method, the exposure amount for exposing the first type of region is less than the necessary exposure amount and not less than half of the necessary exposure amount.

In the above method, the exposure amount for exposing the first type of region is greater than zero and less than half of the necessary exposure amount.

The present invention also provides a 3D printing device, comprising:

an image processing unit, which identifies the contour of the model slice image, and divides the image into a first type area and a second type area; the first type area is an area in the image within a preset range from the contour; the first type area The second-class area is the area other than the first-class area in the image;

The exposure control unit controls the exposure unit to expose the first type area and the second type area respectively according to a preset strategy, and the exposure amount of the first type area is smaller than the exposure amount of the second type area ;

The exposure unit performs exposure under the control of the exposure control unit.

The above equipment also includes:

The storage unit, for the determined model slice thickness, stores at least one set of correspondences of the first type of area exposure parameter, the second type of area exposure parameter and the first distance value; wherein, the first type of area is in the image. an area within a range of a first distance value from the contour;

as well as,

The obtaining unit obtains the user's instruction, and determines the first type of area exposure parameter, the second type of area exposure parameter and the first distance value in a set of corresponding relationships to perform resin photocuring of the sliced pattern; sending the first distance value To the image processing unit, the first type of area exposure parameters and the second type of area exposure parameters are sent to the exposure control unit.

Alternatively, the above equipment also includes:

an acquisition unit, configured to acquire a set of first-type area exposure parameters, second-type area exposure parameters and first distance values input by the user; and, sending the first distance value to an image processing unit, The class area exposure parameters and the second class area exposure parameters are sent to the exposure control unit.

In the above-mentioned equipment, the exposure control unit, the exposure intensity used for the second type of area exposure is not less than the necessary exposure intensity required to complete the resin photocuring of the slice thickness; the exposure amount of the second type area exposure is not less than the completed slice thickness. Necessary exposure for resin photocuring.

In the above equipment, the exposure control unit, the exposure intensity used for the first type of area is not greater than the exposure intensity of the second type of area exposure, and is greater than the critical exposure intensity that can induce photocuring of the resin; for the first type of area The exposure used was less than the exposure necessary to complete the photocuring of the resin at the thickness of the slice.

In the above device, the exposure control unit adopts zero exposure duration for the first type area or zero exposure light intensity for the first type area, that is, does not expose the first type area.

In the above device, the exposure amount of the exposure control unit for exposing the first type of area is less than the necessary exposure amount and not less than half of the necessary exposure amount.

In the above device, the exposure amount of the exposure control unit for exposing the first type of area is greater than zero and less than half of the necessary exposure amount.

In the above device, the exposure strategy of the exposure control unit includes simultaneously starting exposure to the first type area and the second type area at the same time; or, starting the exposure of the first type area and then performing the exposure of the second type area; or, starting After the exposure of the second type of area, the exposure of the first type of area is performed; or, after the exposure of the first type of area is completed, the exposure of the second type of area is performed; or, after the exposure of the second type of area is completed, the exposure of the first type of area is performed .

Embodiments of the present invention further provide a non-transitory machine-readable storage medium, on which executable codes are stored, and when the executable codes are executed by a processor of an electronic device, the processor is caused to execute the above method.

In this embodiment of the present application, the image is divided into two parts, an edge area and a center area. Wherein, the edge area is an area in the image within a preset range from the contour. The edge and center areas of the image are exposed separately, and the edge areas are exposed to a lower amount. When the light that excites the resin for photocuring cannot be completely irradiated vertically to the printing plane, although the light is refracted, scattered, and diffusely reflected in the resin, the light will diffuse to the outside of the slice boundary, but in this embodiment, the slice edge area is In the case of using a lower exposure amount, the light diffused to the outside of the sliced image is not enough to cause the curing of the resin outside the image range, which ensures the accuracy of image printing. Due to refraction, scattering, diffuse reflection, etc., the light exposed in the central area will enter the edge area, promoting the curing of the resin in the edge area.

The user sets printing parameters for the edge area and the center area, including exposure intensity and exposure duration, and obtains the exposure amount through the exposure intensity and exposure duration. The method of the invention performs exposure according to the printing parameters set by the user through preset strategies. The user can set the parameters by specifying the printing parameters by input, or by selecting one set of parameters from the preset multiple sets of printing parameters to execute the printing operation.

In the embodiment of the present invention, the exposure duration of the edge region is set to 0, that is, only the central region can be exposed, and the edge region is not exposed. When the second type area (ie the central area) is exposed, due to the existence of scattering and refraction, the resin overflowing to the first type area (ie the edge area) is cured, so the edge area does not need to be exposed separately. Therefore, the present embodiment also has the effect of high printing precision and improved printing efficiency when a better edge area size is obtained.

It is to be understood that both the foregoing general description and the following detailed description are exemplary and explanatory only and are not limiting of the present application.

Description of drawings

The above and other objects, features and advantages of the present application will become more apparent from the more detailed description of the exemplary embodiments of the present application in conjunction with the accompanying drawings, wherein the same reference numerals generally represent the exemplary embodiments of the present application. same parts.

Figure 1a is a schematic side view of photocuring under ideal conditions;

Figure 1b is a schematic side view of photocuring under actual conditions;

2 is a first schematic diagram of a sliced image area shown in the present application;

3 is another schematic diagram of the sliced image area shown in the present application;

FIG. 4 is a schematic structural diagram of the 3D printing device shown in this application.

detailed description

Preferred embodiments of the present application will be described in more detail below with reference to the accompanying drawings. While preferred embodiments of the present application are shown in the drawings, it should be understood that the present application may be embodied in various forms and should not be limited by the embodiments set forth herein. Rather, these embodiments are provided so that this application will be thorough and complete, and will fully convey the scope of this application to those skilled in the art.

The terminology used in this application is for the purpose of describing particular embodiments only and is not intended to limit the application. As used in this application and the appended claims, the singular forms "a," "the," and "the" are intended to include the plural forms as well, unless the context clearly dictates otherwise. It will also be understood that the term "and/or" as used herein refers to and includes any and all possible combinations of one or more of the associated listed items.

It should be understood that although the terms "first", "second", "third", etc. may be used in this application to describe various information, such information should not be limited by these terms. These terms are only used to distinguish the same type of information from each other. For example, the first information may also be referred to as the second information, and similarly, the second information may also be referred to as the first information without departing from the scope of the present application. Thus, a feature defined as "first" or "second" may expressly or implicitly include one or more of that feature. In the description of the present application, "plurality" means two or more, unless otherwise expressly and specifically defined.

The 3D printing technology based on SLA (Stereo lithography Appearance) uses liquid photosensitive resin as raw material, uses the rapid polymerization of photosensitive resin under blue-violet light or ultraviolet light irradiation, and controls the illumination range, layer-by-layer curing, and orderly molding, and finally generates a three-dimensional three-dimensional member.

The SLA printing process is to first slice the three-dimensional model to obtain a cross-sectional image of each slice, and use blue-violet light or ultraviolet light to cure the resin according to the cross-sectional image of the slice. After curing a slice, the lift table moves in the vertical direction. The height of one slice is determined, and then the resin is cured according to the image of the next slice to complete the curing of the next slice, so that the layers are superimposed to form a three-dimensional entity.

During this process, precise control of light is key to the accuracy of 3D printing.

The prior art attempts to make the light rays strike the resin parallel and perpendicular to each other using various methods. For example, the outgoing light of the light source at the focal position is changed into parallel light by using a reflective bowl or a lens, and the light source is changed into a surface light source by using a light-emitting matrix instead of a point light source, and so on. However, in practice, the direction of all light cannot be completely perpendicular to the printing plane, and objectively, there are still some rays that cannot be perpendicular to the printing plane. Therefore, due to the refraction, scattering, and diffuse reflection of light in the resin, the light will diffuse to the outside of the slice boundary and solidify the outside of the slice edge.

Figures 1a and 1b are schematic side views of photocuring. As shown in Figure 1a, ideally, the light is perpendicular to the liquid resin, and the liquid resin is cured only in the light range, and its size is consistent with the size of the light range. Figure 1b shows the actual situation where the light cannot be completely perpendicular to the liquid resin, which causes the model to deviate from the theoretical size on the surface in the XY direction. As shown in Figure 1b, the actual printed size of the model will be slightly larger than the designed size of the model. The reason is that on the illumination boundary, the resin outside the edge of the sliced image is also affected by the refracted light, scattered light and other light that overflows the image range. cured.

In order to improve the influence brought by the above-mentioned edge transmission curing effect, the embodiment of the present invention provides a slice subregional exposure processing method, which divides the slice image into two parts, a center area and an edge area, and reduces the edge exposure time, exposure intensity or no exposure to cure. edge, to reduce resin curing outside the edge of the slice, thereby improving the printing accuracy of SLA technology.

The embodiments of the present application provide a 3D printing exposure method as follows.

First, the outline of the model slice image is identified, and the image is divided into the first type area and the second type area;

Wherein, the first type area is an area in the image within a preset range of the contour; and the second type area is an area other than the first type area in the image.

FIG. 2 is a first schematic diagram of a sliced image area shown in an embodiment of the present application.

Referring to FIG. 2 , in this example, the processor first identifies the closed contour 201 of the edge in the sliced image, and the area enclosed by the closed contour 201 is the image area.

The processor may match the closed contour 201 with its corresponding preset extension mode, and obtain a closed extension contour 203 generated by extending the closed contour 201 toward the inner side of the image area according to the corresponding preset extension mode.

The preset extending manner may be extending according to a preset extending distance. The processor can divide the image area into an edge exposure area 202 surrounded by the closed contour 201 and the closed extension contour 203, that is, the first type of area described in this application, and a central exposure area 204 located in the inner direction of the edge exposure area 202, that is, The second type of area described in this application.

FIG. 3 is another schematic diagram of a sliced image area shown in an embodiment of the present application.

Referring to FIG. 3 , the cross section of the object to be printed is annular. Unlike the image shown in the first schematic diagram, the image shown in this example has both an outer contour and an inner contour.

The processor slices the closed contour 301 and the closed contour 307 at the edge of the image area, and the area enclosed by the closed contour 301 and the closed contour 307 is the image area.

The processor matches the corresponding preset extension mode for the closed contour 301 , matches the corresponding preset extension mode for the closed contour 307 , and obtains a closed extension contour generated by extending the closed contour 301 to the inner direction of the slice area according to the corresponding preset extension mode. 303 , acquiring a closed extension contour 305 generated by extending the closed contour 307 toward the inner side of the slice region according to a preset extension manner corresponding to the closed contour 307 .

The image area enclosed by the closed outline 301 and the closed outline 307 is divided into: a first edge exposure area 302 enclosed by the closed outline 301 and the closed extension outline 303, and a second edge enclosed by the closed outline 307 and the closed extension outline 305. The exposure area 306 , and the central exposure area 304 located in the inner direction of the edge exposure area 302 and the edge exposure area 306 . The first edge exposure area 302 and the second edge exposure area 306 are the first type of areas described in the present application, and the central exposure area 304 is the second type of areas described in the present application.

In addition to the image shapes shown in Figures 2 and 3, the application does not limit the shape of the image to be printed. For example, the contour of the image is an irregular curve, or the sliced image has multiple inner contours due to multiple hollows inside the model. Wait.

In the present application, the first type of area is an area with a preset width inward according to the outline of the graphic. The width can be set according to printing needs, and the unit is a length unit such as micrometers or millimeters, or the number of pixels.

Also, the present application does not limit the method of dividing the image into a plurality of regions. In the above embodiment, an extended contour extending a certain distance from the image contour is obtained based on the image contour, and then the first type of exposure area enclosed by the image contour and the extended contour is obtained.

In another way, the processor does not need to calculate the extended contour position according to the image contour according to the above embodiment, but according to the image contour, the processor obtains the pixel points within the preset distance range from the pixel points on the image contour as the first type of exposure area. In the calculation of the distance, the distance calculation may be performed according to the x-axis and the y-axis of the image pixel coordinate system, and may also be implemented by other existing methods, which is not limited in the present invention.

Next, the first type of area and the second type of area are exposed according to preset exposure parameters, and the exposure amount of the first type of area is smaller than the exposure amount of the second type of area.

Taking the image shown in FIG. 2 as an example, the edge exposure area 202 and the central exposure area 204 are exposed, so that the photosensitive resin in the corresponding area is cured. The exposure amount of the edge exposure area 202 is smaller than the exposure amount of the central exposure area 204 .

Taking the image shown in FIG. 3 as an example, the edge exposure area 302 , the edge exposure area 306 and the center exposure area 304 are exposed.

The exposure amount of the edge exposure area 302 and the exposure amount of the edge exposure area 306 are both smaller than the exposure amount of the center exposure area 304 .

The exposure amounts of the edge exposure area 302 and the edge exposure area 306 may or may not be equal. In addition, the magnitude relationship between the exposure amounts of the edge exposure area 302 and the edge exposure area 306 can be set as required, which is not limited in this application.

Exposure parameters include exposure intensity and exposure duration. Exposure is the product of exposure intensity and exposure duration. In order to realize that the exposure amount of the edge exposure area (ie, the first type of exposure area) shown in FIG. 2 and FIG. 3 is smaller than that of the center exposure area (and the second type of exposure area). Exposure parameters can be set as follows.

Define the following concepts of critical light intensity, necessary light intensity, necessary duration, and necessary exposure.

Critical light intensity: The photocuring reaction must be initiated under a specific light intensity higher than that, and it will not cure below this specific light intensity. The specific light intensity is defined as the critical light intensity.

Necessary light intensity: The 3D model slice has a thickness, and the light will attenuate when it passes through the resin. To make the resin in the deepest part of the slice light-curing, it is necessary to increase the light intensity, which is defined as the necessary light intensity.

The necessary light intensity is obtained using the following calculation method:

I=I ₀ ×exp(-a×d)

in:

d is the light penetration depth,

a is the resin absorption coefficient,

I ₀ is the initial light intensity.

Necessary time: The slice has a thickness, so it takes a certain time to fully cure based on the necessary light intensity, and this time is the necessary time.

Based on the above definitions, the exposure required to fully cure one layer of slices is the necessary exposure.

Necessary exposure = Necessary light intensity × Necessary time.

Therefore, the exposure parameters of the first type area and the second type area in the present invention are related to the material of the photosensitive resin used, the slice thickness; and further related to the width of the first type area.

Assuming that the resin material remains unchanged, for slices with different thicknesses, there are preset at least one set of correspondence between the first type of area exposure parameters, the second type of area exposure parameters and the first distance value. The first type of area is an area in the image within a range of a first distance value from the contour. That is to establish the corresponding relationship of multiple sets of parameter values, or the corresponding relationship of multiple sets of parameter value ranges, which is used to determine the exposure intensity and exposure time of the first type area required for photocuring printing, and the exposure intensity and exposure time of the second type area. duration, and the width value of the first category area.

The user determines the parameters in the preset corresponding relationship of multiple sets of parameters for performing the resin light curing of the slice pattern. The way for the user to determine the parameters can be: for the determined slice thickness, the system provides at least one parameter group, and the user selects one of the parameters for the photocuring of the slice; The value range may be affected by the value range of one or more other parameters. The user confirms the parameters used for photocuring of this layer slice within the parameter value range, for example, including the exposure of the first type of area described above. Intensity, Exposure Duration, Exposure Intensity and Exposure Duration for Type 2 Areas, and Width Values for Type 1 Areas.

In another method of determining parameters in the embodiment of the present invention, the user inputs the parameters required for photocuring of the slice, and then, according to a set of first-type area exposure parameters, second-type area exposure parameters, and first distance values input by the user , and perform resin photocuring. The first type of area is an area in the image within a range of a first distance value from the contour. Those skilled in the art can use the method of the above embodiment to determine specific parameters according to the shape characteristics of different printed parts, and the present application does not limit the specific values.

In the embodiment of the present invention, the exposure intensity of the second type of area exposure is not less than the necessary exposure intensity required to complete the resin photocuring of the slice thickness; necessary exposure. Based on this, the following example illustrates the value relationship between parameters.

Ic represents the exposure intensity of the central exposure area shown in FIGS. 2 and 3 , and Tc represents the exposure duration of the central exposure area. Ie represents the exposure intensity of the edge exposure area, and Te represents the exposure duration of the edge exposure area. Then the exposure parameters can be set in the following ways:

In the first implementation manner, the central exposure area and the edge exposure area use the same exposure intensity and use different exposure durations.

That is, Ic is the same as Ie, and is equal to or greater than the necessary light intensity.

Tc is greater than or equal to the necessary duration, and Te is less than the necessary duration, but greater than 1/2 of the necessary duration. The exposure of the central exposure area is relatively large, which will partially cure the resin in the edge exposure area. Therefore, by reducing the exposure time of the edge exposure area, the exposure time of the light radiating outside the image is not enough to complete the resin curing.

In the second method, the central exposure area and the edge exposure area use different exposure intensities and use the same exposure duration.

Ic is greater than or equal to the necessary light intensity, and Ie is less than the necessary light intensity, but greater than the critical light intensity.

Tc is the same as Te, and both are greater than or equal to the necessary duration.

The higher exposure in the center exposure area will partially cure the resin in the edge exposure areas. By reducing the edge exposure intensity, the degree of curing of the resin outside the edge by the transmitted light is reduced.

In the third method, the central exposure area and the edge exposure area use different exposure intensities and different exposure durations.

Specifically, Ic is greater than or equal to the necessary light intensity; Ie is less than the necessary light intensity, but greater than the critical light intensity.

Tc is greater than or equal to the necessary duration.

Te is less than the necessary duration and greater than 1/2 of the necessary duration, and the exposure amount (Ie×Te) of the edge exposure area should be greater than 1/2 of the necessary exposure amount.

In the fourth manner, the exposure amount of the edge area exposure is greater than zero and less than half of the necessary exposure amount.

Specifically, the exposure amount (Ie×Te) of the edge exposure area should be less than 1/2 of the necessary exposure amount.

The higher exposure in the center exposure area will partially cure the resin in the edge exposure areas. By reducing the edge exposure intensity and exposure time, the curing of the resin outside the edge by the transmitted light is reduced.

In addition to the above implementation manners, any implementation manner in which the exposure amount of the edge exposure area is smaller than the exposure amount of the central exposure area can achieve the purpose of the present invention. Based on the relationship that the exposure amount is the product of the exposure intensity and the exposure duration, the exposure intensity and exposure duration of different exposure areas may be specifically set.

In the fifth way, the central area is exposed and the edge area is not exposed.

Specifically, Ic is greater than or equal to the necessary light intensity; Tc is greater than or equal to the necessary duration; Te is equal to zero; or Ie is equal to zero, so that the edge area is not actually exposed.

Taking the example shown in FIG. 2 , the relationship between the exposure parameters of the edge exposure area and the exposure parameters of the central exposure area may be as follows.

The exposure duration of the edge exposure area 202 is shorter than the exposure duration of the central exposure area 204; the exposure intensity of the edge exposure area 202 is smaller than the exposure intensity of the central exposure area 204;

Alternatively, the exposure duration of the edge exposure area 202 is equal to the exposure duration of the central exposure area 204, and the exposure intensity of the edge exposure area 202 is smaller than the exposure intensity of the central exposure area 204;

Alternatively, the exposure duration of the edge exposure area 202 is less than the exposure duration of the central exposure area 204, and the exposure intensity of the edge exposure area 202 is equal to the exposure intensity of the central exposure area 204;

Alternatively, the exposure duration of the edge exposure area 202 is shorter than the exposure duration of the central exposure area 204 , and the exposure intensity of the edge exposure area 202 is smaller than the exposure intensity of the central exposure area 204 .

When the above relationship is satisfied, the exposure light intensity of the edge exposure area should be greater than the critical light intensity; and, the exposure intensity of the central exposure area is greater than or equal to the necessary light intensity, and the exposure duration of the central exposure area is greater than or equal to the necessary duration.

Alternatively, the exposure duration of the edge exposure area 202 is 0; the exposure amount of the central exposure area is greater than or equal to the necessary exposure amount.

In another embodiment of the present invention, the exposure amount of the edge exposure area should be greater than half of the necessary exposure amount.

In addition to the above selection methods of exposure parameters, on the premise that the exposure amount of the edge exposure area is less than the exposure amount of the center exposure area, the present invention does not exclude that one of the parameters of the exposure intensity or exposure duration of the edge exposure area is greater than the corresponding one of the center exposure area. How the parameter is implemented.

According to the selection of the above exposure intensity and exposure duration parameters, the exposure of each slice of the 3D model can be performed, and the light curing operation of each slice of the 3D model can be repeatedly performed until the printing of the 3D model is completed.

It can be seen from the above description that in the case of using a certain photosensitive resin, the exposure parameter and the slice thickness have a certain corresponding relationship. In some 3D printing methods, according to different printing speed and precision requirements, when slicing a 3D model, there are cases where different thicknesses are used to slice different parts of the model. In this case, based on the method described above, the processor can determine the necessary intensity, necessary duration and other parameters of the required exposure corresponding to slices of different thicknesses, and with the layer-by-layer printing of the 3D model slices, dynamic Adjust the parameter range.

And, the selection range of the exposure parameters and the relationship between the parameters of different exposure areas are described above. Those skilled in the art can determine the specific parameters according to the shape characteristics of different prints using the method of the above-mentioned embodiment, and the application does not limit the specific parameters. value of .

On the basis of determining the exposure parameters above, according to the exposure intensity and exposure duration of the edge exposure area and the center exposure area, the edge exposure area and the center exposure area have multiple exposure sequences, such as the following.

In the first way, a 2D vector polygon slice is obtained, and the edge exposure area and the center exposure area are obtained respectively. The edge exposure area and the central exposure area use the same exposure intensity I, which is greater than or equal to the necessary light intensity. The exposure duration Tc of the central exposure area is greater than or equal to the necessary duration; the exposure duration Te of the edge exposure area is less than the necessary duration and greater than 1/2 of the necessary duration.

The edge exposure area and the central exposure area of the sliced image simultaneously begin to use the exposure intensity I to carry out resin curing. Since Te is less than Tc, the slice edge exposure area ends exposure prior to the central exposure area.

The second way is to obtain 2D vector polygon slices, and obtain the edge exposure area and the center exposure area respectively. Using the same parameters as the first method.

The central exposure area of the slice is firstly exposed with the light intensity I, and the edge exposure area of the slice is exposed with the same light intensity I after the Tc-Te time. The edge exposure area and the central exposure area end exposure at the same time.

The third way is to obtain 2D vector polygon slices, and obtain the edge exposure area and the center exposure area respectively. Using the same parameters as the first method.

The exposure area of the center of the slice is firstly exposed with the light intensity I, and the edge of the slice is exposed and cured with the same light intensity after the time T, where T<(Tc-Te). After the edge exposure area is exposed to Tc-Te-T, the exposure of the center exposure area ends.

The fourth way is to obtain 2D vector polygon slices, and obtain the edge exposure area and the center exposure area respectively.

The edge exposure area and the central exposure area use the same exposure duration, which is greater than or equal to the necessary duration. The exposure intensity Ic is used for the central exposure area, and the exposure intensity Ie is used for the edge exposure area to start exposure at the same time, and end exposure at the same time.

The fifth way is to obtain 2D vector polygon slices, and obtain the edge exposure area and the center exposure area respectively.

The exposure intensity of the central exposure area is Ic, which is greater than or equal to the necessary light intensity; the exposure intensity of the edge exposure area is Ie, which is less than the necessary light intensity and greater than the critical light intensity. The exposure time of the central exposure area is Tc, which is greater than or equal to the necessary time; the exposure time of the edge exposure area is Te, which is less than the necessary time and greater than 1/2 of the necessary time.

The exposure amount Ie×Te of the edge exposure area is greater than 1/2 of the necessary exposure amount, the light intensity Ic is used in the central exposure area of the slice, and the light intensity Ie is used at the edge of the slice, and the exposure is started at the same time. Since Te is smaller than Tc, the exposure area at the edge of the slice ends the exposure first.

The sixth way is to obtain 2D vector polygon slices, and obtain the edge exposure area and the center exposure area respectively.

The central exposure area is exposed at the exposure intensity Ic, and after the Tc-Te time, the exposure area at the edge of the slice is exposed at the exposure intensity Ie. The central exposure area and the edge exposure area end exposure at the same time.

In the seventh method, obtain 2D vector polygon slices, and obtain the edge exposure area and the center exposure area respectively. Use the parameter settings in the sixth method above.

The exposure intensity Ic is used to start exposure in the central exposure area of the slice, and after the duration T, the exposure intensity Ie is used in the exposure area at the edge of the slice, where T<(Tc-Te. The exposure of the exposure area ends.

Including the above examples, various exposure strategies can be adopted in the embodiment of the present invention, including: starting the exposure of the first type area and the second type area at the same time; or, performing the exposure of the second type area after starting the exposure of the first type area; Or, the exposure of the first type of area is performed after the exposure of the second type of area is started; or, the exposure of the second type of area is performed after the exposure of the first type of area is completed; or, the first type of area is performed after the exposure of the second type of area is completed. area exposure.

In addition to the above embodiments, exposure can also be done region by region.

For example, taking the example shown in FIG. 2 , the exposure of the area 202 may be performed after the exposure of the area 204 is completed. Alternatively, the exposure of the area 204 is performed after the exposure of the area 202 is completed.

For example, taking FIG. 3 as an example, the edge exposure area 302 and the edge exposure area 306 that belong to the first type of exposure area can be exposed first, and after the exposure is completed, the exposure of the central exposure area 304 can be performed. . Alternatively, the exposure of the two

edge exposure areas

302 and 304 is performed after the exposure of the central exposure area 304 is completed.

Also referring to FIG. 3 , the processor can also complete the exposure of the three

regions

302 , 304 , and 306 one by one in a certain order, and the specific exposure order of the three regions is not limited in the present invention.

According to the above description, the refraction of light after passing through the liquid crystal screen, the refraction, scattering, and reflection of light in the resin cause the light to radiate out of the image area, causing the resin at the edge of the image to cure. In the prior art, the exposure amount used is greater than or equal to the necessary exposure amount, and when the light intensity radiated outside the image area is greater than the critical light intensity, the resin outside the edge of the slice is cured. In order to reduce the influence of transmitted light intensity on the area outside the slice, the present application provides a mode of partition exposure, which divides the slice image into a first type of exposure area in the edge area and a second type of exposure area outside the first type of area. part. And different exposure parameters are used for exposure and curing, the exposure amount used in the center of the slice is greater than or equal to the necessary exposure amount, and the exposure amount is reduced by reducing the exposure intensity or exposure time at the edge of the slice. It is difficult to cause the curing of the resin outside the slice, thereby improving the accuracy of 3D printing.

In another embodiment of the 3D printing method provided by the present invention. The central exposure area is normally exposed and cured, and the edge area is cured with zero exposure, that is, no exposure. Taking the image shown in FIG. 2 as an example, the central exposure area 204 is exposed, so that the photosensitive resin in the corresponding area is cured. The edge exposed regions 202 are not exposed to cure. Taking the image shown in FIG. 3 as an example, the exposure amount of the edge exposure area 302 and the edge exposure area 306 is zero, that is, the edge exposure area 302 and the edge exposure area 306 are not exposed and cured. In this method, the curing of the resin corresponding to the edge region is realized by utilizing the light entering the edge region by means of scattering, refraction, etc. during the exposure of the central region. The method includes:

Identify the contour of the model sliced image, and divide the image into a first type area (ie edge area) and a second type area (ie central area);

Wherein, the first type of area is an area in the image that is within a preset range of the contour; the second type of area is an area outside the first type of area in the image;

Expose the second type of area with an exposure intensity not less than the necessary exposure intensity required to complete the photocuring of the resin for the thickness of the model slice; .

In this method, firstly, the exposure intensity and exposure amount of the central area are related to the thickness of the model slice; secondly, this method utilizes the light entering the edge area through scattering and refraction during the exposure process of the central area to cure the resin corresponding to the edge area. Therefore, the width value of the edge region can be determined according to the slice thickness through the preset corresponding relationship. An area in the image within the range of the width value from the outline is determined as an edge area.

The preset correspondence described in this paper can store the selection of values, and establish a one-to-many or one-to-one correspondence, that is, one slice thickness can correspond to one width value or multiple width values; therefore, different Slice thickness may also correspond to the same width value. The preset corresponding relationship described in this paper can also be calculated by a function, taking the slice thickness as a variable, and calculating the required width value of the edge region. The present invention does not limit the method for determining the size of the edge region by those skilled in the art using other methods.

It can be expected that, in this embodiment, the value of the width value is suitable for a smaller value. The unit is usually a unit of length such as microns, or the number of pixels.

In addition, according to a preset model, the exposure intensity of the central area is determined according to the slice thickness. The exposure intensity must be greater than the exposure intensity necessary to complete the photocuring of the resin for this slice thickness. However, since exposure of the center area partially cures the resin in the edge exposed areas, the exposure intensity of the center area is also related to the width of the edge area. Therefore, according to the preset model, according to the slice thickness, the combination of the exposure intensity of the central region and the width value of the edge region is determined. That is, with the same slice thickness, a larger exposure intensity can correspond to a relatively larger edge area width. On the other hand, when the exposure amount required for the same resin material is the same, a larger exposure intensity can be used to have a shorter exposure time. Therefore, those skilled in the art can establish a corresponding function according to the characteristics of the resin used, or obtain one or more sets of numerical combinations of exposure intensity and edge region width under a certain slice thickness through experiments.

In the embodiment of the present invention, the exposure amount of the central exposure area is relatively large, and the resin in the edge exposure area will be partially cured. By not exposing the cured edges, the curing of the resin outside the edges by transmitted light is reduced.

The embodiment of the present invention also provides a 3D printing device to realize the 3D printing method described above. The 3D printing equipment includes:

The image processing unit 41 recognizes the outline of the model slice image, and divides the image into a first type area and a second type area; the first type area is an area with a preset width extending from the outline to the inside of the image; the The second type of area is the area other than the first type of area in the image;

The exposure control unit 42 controls the exposure unit to expose the first type area and the second type area respectively according to preset exposure parameters, and the exposure amount of the first type area is smaller than that of the second type area. exposure;

The exposure unit 43 completes photocuring of the resin by exposure.

In the above device, the exposure control unit 42 starts exposing the first type area and the second type area at the same time; or, according to a preset sequence, respectively completes the exposure of the first type area and the second type area.

In the above device, the image processing unit is also used for slicing the model;

The exposure control unit obtains the thickness of the slice of the current image to be exposed, obtains the necessary exposure intensity required to complete the photocuring of the resin with the slice thickness, and uses the necessary exposure intensity to complete the necessary exposure duration for curing the resin; and,

The exposure control unit controls the exposure unit so that the exposure intensity of the second type area is not less than the necessary exposure intensity, and the exposure duration of the second type area is not less than the necessary exposure duration;

The exposure control unit controls the exposure unit so that the exposure intensity of the first type of area is not greater than the exposure intensity of the second type of area, and is greater than the critical exposure intensity that can induce photocuring of the resin, and the exposure intensity used for the first type of area is The exposure amount is less than the necessary exposure amount required to complete the resin photocuring of the slice thickness;

Alternatively, the exposure duration used for the first type area is zero or the exposure light intensity used for the first type area is zero, so that the first type area is not actually exposed; or, the exposure intensity of the first type area and the first type area are The exposure amount obtained by long exposure for the exposure time of the class area is less than the necessary exposure amount determined by the necessary exposure intensity and the necessary exposure duration, and not less than half of the necessary exposure amount; or, the exposure amount for the first class area exposure greater than zero and less than half of the necessary exposure.

For the values of the first type of area exposure parameter, the second type of area exposure parameter, and the value of the first type of area range value, please refer to the description of the above method.

The device according to an embodiment of the present invention further includes: a storage unit that stores, for the determined model slice thickness, at least one set of correspondences between the first type of area exposure parameters, the second type of area exposure parameters, and the first distance value; wherein, The first type of area is an area in the image within a range of a first distance value from the contour;

as well as,

The device according to an embodiment of the present invention further includes: an acquisition unit configured to acquire a set of first-type area exposure parameters, second-type area exposure parameters, and a first distance value input by a user; Send to the image processing unit, and send the first type of area exposure parameters and the second type of area exposure parameters to the exposure control unit.

An embodiment of the present invention further provides a non-transitory machine-readable storage medium on which executable codes are stored, wherein when the executable codes are executed by a processor of an electronic device, the processor is caused to execute method described above.

Regarding the apparatus in the above-mentioned embodiment, the specific manner in which each module performs the operation has been described in detail in the embodiment of the method, and will not be described in detail here.

Those skilled in the art will also appreciate that the various exemplary logical blocks, modules, circuits, and algorithm steps described in connection with the applications herein may be implemented as electronic hardware, computer software, or combinations of both.

Various embodiments of the present application have been described above, and the foregoing descriptions are exemplary, not exhaustive, and not limiting of the disclosed embodiments. Numerous modifications and variations will be apparent to those of ordinary skill in the art without departing from the scope and spirit of the described embodiments. The terminology used herein was chosen to best explain the principles of the various embodiments, the practical application or improvement over the technology in the marketplace, or to enable others of ordinary skill in the art to understand the various embodiments disclosed herein.

Claims

A 3D printing method, comprising:

Identify the contour of the model slice image, and divide the image into a first-type area and a second-type area;

Wherein, the first type of area is an area in the image within a preset range of the contour;

The second type of area is an area other than the first type of area in the image;

The first type area and the second type area are exposed according to a preset strategy, and the exposure amount of the first type area is smaller than the exposure amount of the second type area.
The method of claim 1, wherein:

For the determined model slice thickness, at least one set of correspondences of the first type of area exposure parameter, the second type of area exposure parameter and the first distance value are preset;

And, according to the thickness of the slice, determine the first type of area exposure parameter, the second type of area exposure parameter and the first distance value in a set of correspondence to perform the resin photocuring of the sliced pattern;

The first type of area is an area in the image within a range of a first distance value from the contour.
The method of claim 1, wherein:

Obtain a set of first-type area exposure parameters, second-type area exposure parameters and first distance values input by the user, and perform resin photocuring;

The first type of area is an area in the image within a range of a first distance value from the contour.
The method according to one of claims 1 to 3, characterized in that:

The exposure parameters include: exposure intensity and exposure duration;

The exposure intensity and exposure duration are used to obtain the exposure amount.
The method according to any one of claims 4, wherein the preset exposure strategy comprises:

The first type of area and the second type of area start to be exposed at the same time;

Or, perform exposure of the second type of area after starting the exposure of the first type of area;

Alternatively, the exposure of the first type of area is performed after the exposure of the second type of area is started;

Or, after the exposure of the first type of area is completed, the exposure of the second type of area is performed;

Alternatively, the exposure of the first type of area is performed after the exposure of the second type of area is completed.
The method of claim 5, further comprising:

Obtain the exposure parameters of the second type of area;

Wherein, the exposure intensity of the second type of area exposure is not less than the necessary exposure intensity required to complete the resin photocuring of the slice thickness;

The exposure of the second type of area exposure is not less than the necessary exposure to complete the photocuring of the resin for the thickness of the slice.
The method according to claim 6, wherein:

The exposure intensity of the first type of area exposure is not greater than the exposure intensity of the second type of area exposure, and is greater than the critical exposure intensity capable of causing photocuring of the resin;

The exposure of the first type of area exposure is less than the exposure necessary to complete the photocuring of the resin through the thickness of the slice.
The method according to claim 7, wherein:

The exposure intensity of the second type area is the same as that of the first type area, and the exposure duration of the first type area is shorter than that of the second type area;

Alternatively, the exposure duration of the second type area is the same as that of the first type area, and the exposure intensity of the first type area is lower than that of the second type area;

Alternatively, the exposure duration of the first type area is shorter than the exposure duration of the second type area, and the exposure intensity of the first type area is smaller than the exposure intensity of the second type area.
The method of claim 6, wherein:

The exposure duration of the first type of area exposure is zero;

Alternatively, the exposure intensity of the first type of area exposure is zero.
The method according to claim 6, wherein:

The exposure amount for exposing the first type of area is less than the necessary exposure amount and not less than half of the necessary exposure amount.
The method according to claim 6, wherein:

The exposure amount for exposing the first type of region is greater than zero and less than half of the necessary exposure amount.
A 3D printing device, characterized in that it includes:

an image processing unit, which identifies the contour of the model slice image, and divides the image into a first type area and a second type area; the first type area is an area in the image within a preset range from the contour; the first type area The second-class area is the area other than the first-class area in the image;

The exposure control unit controls the exposure unit to expose the first type area and the second type area respectively according to a preset strategy, and the exposure amount of the first type area is smaller than the exposure amount of the second type area ;

The exposure unit performs exposure under the control of the exposure control unit.
The device of claim 12, further comprising:

The storage unit, for the determined model slice thickness, stores at least one set of correspondences of the first type of area exposure parameter, the second type of area exposure parameter and the first distance value; wherein, the first type of area is in the image. an area within a range of a first distance value from the contour;

as well as,

The obtaining unit obtains the user's instruction, and determines the first type of area exposure parameter, the second type of area exposure parameter and the first distance value in a set of corresponding relationships to perform resin photocuring of the sliced pattern; sending the first distance value To the image processing unit, the first type of area exposure parameters and the second type of area exposure parameters are sent to the exposure control unit.
The device of claim 12, further comprising:

an acquisition unit, configured to acquire a set of first-type area exposure parameters, second-type area exposure parameters and first distance values input by the user; and, sending the first distance value to an image processing unit, The class area exposure parameters and the second class area exposure parameters are sent to the exposure control unit.
The device according to any one of claims 12 to 14, characterized in that:

In the exposure control unit, the exposure intensity used for the exposure of the second type of area is not less than the necessary exposure intensity required to complete the resin photocuring of the slice thickness; necessary exposure.
The device of claim 15, wherein:

In the exposure control unit, the exposure intensity used for the first type of area is not greater than the exposure intensity of the second type of area exposure, and is greater than the critical exposure intensity capable of causing photocuring of the resin;

The exposure used for the first type of area is less than the exposure necessary to complete the photocuring of the resin through the slice thickness.
The device of claim 15, wherein:

The exposure control unit adopts zero exposure duration for the first type of area;

Or the exposure control unit adopts zero exposure intensity for the first type of area.
The device of claim 15, wherein:

the exposure control unit starts exposing the first type area and the second type area at the same time;

Or, perform exposure of the second type of area after starting the exposure of the first type of area;

Or, after the exposure of the second type of area is started, the exposure of the first type of area is performed; or, after the exposure of the first type of area is completed, the exposure of the second type of area is performed;

Alternatively, the exposure of the first type of area is performed after the exposure of the second type of area is completed.