WO2022000748A1 - 一种基于光固化材料吸光度性质的dlp打印控制方法 - Google Patents

一种基于光固化材料吸光度性质的dlp打印控制方法 Download PDF

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WO2022000748A1
WO2022000748A1 PCT/CN2020/112094 CN2020112094W WO2022000748A1 WO 2022000748 A1 WO2022000748 A1 WO 2022000748A1 CN 2020112094 W CN2020112094 W CN 2020112094W WO 2022000748 A1 WO2022000748 A1 WO 2022000748A1
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absorbance
solid
light
silo
liquid
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PCT/CN2020/112094
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English (en)
French (fr)
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尹俊
李洋
王一帆
茅棋江
傅建中
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浙江大学
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Priority to US17/762,361 priority Critical patent/US11597159B2/en
Publication of WO2022000748A1 publication Critical patent/WO2022000748A1/zh

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    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B29—WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
    • B29C—SHAPING OR JOINING OF PLASTICS; SHAPING OF MATERIAL IN A PLASTIC STATE, NOT OTHERWISE PROVIDED FOR; AFTER-TREATMENT OF THE SHAPED PRODUCTS, e.g. REPAIRING
    • B29C64/00—Additive manufacturing, i.e. manufacturing of three-dimensional [3D] objects by additive deposition, additive agglomeration or additive layering, e.g. by 3D printing, stereolithography or selective laser sintering
    • B29C64/30—Auxiliary operations or equipment
    • B29C64/386—Data acquisition or data processing for additive manufacturing
    • B29C64/393—Data acquisition or data processing for additive manufacturing for controlling or regulating additive manufacturing processes
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B29—WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
    • B29C—SHAPING OR JOINING OF PLASTICS; SHAPING OF MATERIAL IN A PLASTIC STATE, NOT OTHERWISE PROVIDED FOR; AFTER-TREATMENT OF THE SHAPED PRODUCTS, e.g. REPAIRING
    • B29C64/00—Additive manufacturing, i.e. manufacturing of three-dimensional [3D] objects by additive deposition, additive agglomeration or additive layering, e.g. by 3D printing, stereolithography or selective laser sintering
    • B29C64/10—Processes of additive manufacturing
    • B29C64/106—Processes of additive manufacturing using only liquids or viscous materials, e.g. depositing a continuous bead of viscous material
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B29—WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
    • B29C—SHAPING OR JOINING OF PLASTICS; SHAPING OF MATERIAL IN A PLASTIC STATE, NOT OTHERWISE PROVIDED FOR; AFTER-TREATMENT OF THE SHAPED PRODUCTS, e.g. REPAIRING
    • B29C64/00—Additive manufacturing, i.e. manufacturing of three-dimensional [3D] objects by additive deposition, additive agglomeration or additive layering, e.g. by 3D printing, stereolithography or selective laser sintering
    • B29C64/10—Processes of additive manufacturing
    • B29C64/106—Processes of additive manufacturing using only liquids or viscous materials, e.g. depositing a continuous bead of viscous material
    • B29C64/124—Processes of additive manufacturing using only liquids or viscous materials, e.g. depositing a continuous bead of viscous material using layers of liquid which are selectively solidified
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B29—WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
    • B29C—SHAPING OR JOINING OF PLASTICS; SHAPING OF MATERIAL IN A PLASTIC STATE, NOT OTHERWISE PROVIDED FOR; AFTER-TREATMENT OF THE SHAPED PRODUCTS, e.g. REPAIRING
    • B29C64/00—Additive manufacturing, i.e. manufacturing of three-dimensional [3D] objects by additive deposition, additive agglomeration or additive layering, e.g. by 3D printing, stereolithography or selective laser sintering
    • B29C64/10—Processes of additive manufacturing
    • B29C64/106—Processes of additive manufacturing using only liquids or viscous materials, e.g. depositing a continuous bead of viscous material
    • B29C64/124—Processes of additive manufacturing using only liquids or viscous materials, e.g. depositing a continuous bead of viscous material using layers of liquid which are selectively solidified
    • B29C64/129—Processes of additive manufacturing using only liquids or viscous materials, e.g. depositing a continuous bead of viscous material using layers of liquid which are selectively solidified characterised by the energy source therefor, e.g. by global irradiation combined with a mask
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B29—WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
    • B29C—SHAPING OR JOINING OF PLASTICS; SHAPING OF MATERIAL IN A PLASTIC STATE, NOT OTHERWISE PROVIDED FOR; AFTER-TREATMENT OF THE SHAPED PRODUCTS, e.g. REPAIRING
    • B29C64/00—Additive manufacturing, i.e. manufacturing of three-dimensional [3D] objects by additive deposition, additive agglomeration or additive layering, e.g. by 3D printing, stereolithography or selective laser sintering
    • B29C64/20—Apparatus for additive manufacturing; Details thereof or accessories therefor
    • B29C64/264—Arrangements for irradiation
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B29—WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
    • B29C—SHAPING OR JOINING OF PLASTICS; SHAPING OF MATERIAL IN A PLASTIC STATE, NOT OTHERWISE PROVIDED FOR; AFTER-TREATMENT OF THE SHAPED PRODUCTS, e.g. REPAIRING
    • B29C64/00—Additive manufacturing, i.e. manufacturing of three-dimensional [3D] objects by additive deposition, additive agglomeration or additive layering, e.g. by 3D printing, stereolithography or selective laser sintering
    • B29C64/30—Auxiliary operations or equipment
    • B29C64/386—Data acquisition or data processing for additive manufacturing
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B33—ADDITIVE MANUFACTURING TECHNOLOGY
    • B33Y—ADDITIVE MANUFACTURING, i.e. MANUFACTURING OF THREE-DIMENSIONAL [3-D] OBJECTS BY ADDITIVE DEPOSITION, ADDITIVE AGGLOMERATION OR ADDITIVE LAYERING, e.g. BY 3-D PRINTING, STEREOLITHOGRAPHY OR SELECTIVE LASER SINTERING
    • B33Y10/00—Processes of additive manufacturing
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B33—ADDITIVE MANUFACTURING TECHNOLOGY
    • B33Y—ADDITIVE MANUFACTURING, i.e. MANUFACTURING OF THREE-DIMENSIONAL [3-D] OBJECTS BY ADDITIVE DEPOSITION, ADDITIVE AGGLOMERATION OR ADDITIVE LAYERING, e.g. BY 3-D PRINTING, STEREOLITHOGRAPHY OR SELECTIVE LASER SINTERING
    • B33Y50/00—Data acquisition or data processing for additive manufacturing
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B33—ADDITIVE MANUFACTURING TECHNOLOGY
    • B33Y—ADDITIVE MANUFACTURING, i.e. MANUFACTURING OF THREE-DIMENSIONAL [3-D] OBJECTS BY ADDITIVE DEPOSITION, ADDITIVE AGGLOMERATION OR ADDITIVE LAYERING, e.g. BY 3-D PRINTING, STEREOLITHOGRAPHY OR SELECTIVE LASER SINTERING
    • B33Y50/00—Data acquisition or data processing for additive manufacturing
    • B33Y50/02—Data acquisition or data processing for additive manufacturing for controlling or regulating additive manufacturing processes

Definitions

  • the invention belongs to a printing control method in the technical field of additive manufacturing, and in particular relates to a method for obtaining DLP printing parameters of a photocurable material through the absorbance property of the photocurable material and then controlling the printing.
  • DLP Digital light procession
  • UV ultraviolet light carrying graphic information converts the photosensitive resin in liquid state into a solid with a certain thickness, and repeats single-layer forming for many times to form a three-dimensional model. Determining an accurate exposure time and forming thickness relationship determines a good DLP photocuring technology forming result.
  • the traditional method to determine the relationship between exposure time and forming thickness is to expose the photocurable material for a series of times to obtain its corresponding cured thickness. Since the "Beer-Lambert" law is used to know the basic functional form of this relationship, it can be obtained. According to the multiple "time-layer thickness" data measured in the experiment, the relationship curve between exposure time and forming thickness is obtained by fitting, so as to obtain the exposure time corresponding to any desired cured layer thickness.
  • the model used to measure the layer thickness is difficult to form, it is difficult to accurately obtain the formed layer thickness, and the "time-layer thickness" data point cannot be accurately obtained, which affects the precise forming of softer materials. .
  • the present invention mainly provides a method for controlling DLP printing.
  • the solid absorbance per unit thickness, unit Thickness of liquid absorbance and curing threshold time, a new single-layer curing model based on energy accumulation was established, and the relationship between exposure time and forming thickness was obtained, and the actual forming thickness was calibrated by introducing the solid-liquid absorbance ratio as an evaluation standard.
  • theoretically predict the error of the forming thickness obtain an accurate working curve, avoid repeated forming experiments, avoid material waste, and improve the accuracy of the prediction of the relationship between exposure time and layer thickness, and then accurately control the printing process.
  • the present invention includes the following technical solutions:
  • the present invention realizes the control of DLP printing based on the absorbance property of the photocurable material in six steps:
  • the light absorber is added to the light-curing material, and then the light-curing material after adding the light absorber is used for light curing to perform DLP printing.
  • the printing process is processed in the following ways:
  • the light absorber concentration interval corresponding to the deviated actual solid-liquid absorbance ratio is selected as the selected concentration of the light absorber in the actual photocurable material
  • the curing threshold time t T of the photocurable material of the light absorber concentration is determined in the opto-rheology test and determination step 3;
  • the curing threshold time t T of the material is experimentally obtained by opto-rheological testing.
  • the curing threshold time is obtained by opto-rheological test
  • the solid absorbance per unit thickness and the liquid absorbance per unit thickness of the material are obtained by the method of the present invention, and these parameters are added to the theoretical numerical model proposed by the present invention to obtain the corresponding Printing parameters for DLP printing of the material.
  • t T represents the curing threshold time
  • H represents the curing thickness
  • e represents the natural constant
  • the curing thickness H required for printing is substituted into the single-layer curing model to obtain the exposure time t H , and the DLP printing control is realized according to the exposure time t H .
  • the single-layer curing model proposed in the present invention is a photo-curing model based on light energy, which includes the liquid absorbance and solid absorbance per unit thickness and the threshold value of curing energy.
  • the curing energy threshold is a critical value for the curing energy.
  • the depth represents the curing depth, and the liquid solidifies into a solid.
  • the cure energy threshold is obtained by multiplying the cure threshold time by the energy density.
  • R sl ' represents the theoretical prediction value of the solid-liquid absorbance ratio
  • a 1 represents the slope of the linear fitting data of the relationship between the solid absorbance per unit thickness and the concentration of the light absorber
  • a 2 represents the relationship between the liquid absorbance per unit thickness and the concentration of the light absorber
  • the slope of the linear fitting data b 1 represents the intercept of the linear fitting data of the relationship between the solid absorbance per unit thickness and the concentration of the light absorber
  • b 2 represents the linear fitting data of the relationship between the liquid absorbance per unit thickness and the concentration of the light absorber, respectively intercept
  • c d denotes a light absorber concentration.
  • a1, b1, a2, b2 are obtained by fitting the absorbance per unit thickness obtained by the test and the numerical point of the concentration of the light absorber.
  • changing the concentration of the light absorber in the photocurable material obtains a functional relationship between the ratio of the solid absorbance per unit thickness and the liquid absorbance per unit thickness compared to the concentration of the light absorber.
  • the present invention proposes the solid absorbance in the DLP light curing process for the first time.
  • the present invention uses the absorbance tester shown in FIG. 1 to test and obtain it.
  • the liquid absorbance A l of the unit thickness in the described 1) and the solid absorbance A s of the unit thickness are obtained by using the absorbance testing instrument of the present invention;
  • the absorbance testing instrument comprises the transparent upper end cover of the silo, the silo wall, the silo
  • the transparent lower end cover, the transparent upper end cover of the silo and the transparent lower end cover of the silo are connected by the silo wall, so that the transparent upper end cover of the silo, the silo wall and the transparent lower end cover of the silo together form a sealed silo.
  • UV light is arranged above the transparent upper end cover, and a photometer is arranged below the silo, which is connected to the display screen.
  • the light-cured material is filled with the silo as the object to be tested.
  • test procedure for testing with an absorbance test instrument is as follows:
  • the silo When no substance is placed in the silo, the silo is empty, and the UV ultraviolet light is vertically injected into the silo from the upper part of the transparent upper end cover of the silo. After the ultraviolet light, the optical density displayed on the display screen of the photometer is taken as the incident optical density I i ;
  • the light-cured material to be tested in the bin After that, put the light-cured material to be tested in the bin, the light-cured material is filled with the bin as the object to be tested, and the UV light is vertically injected into the bin from the upper part of the transparent upper end cover of the bin, and the luminosity under the bin is
  • the meter receives the ultraviolet light after passing through the photocurable material at its own photosensitive position, and the optical density initially displayed on the display screen of the photometer is taken as the ultraviolet light through the thickness of the liquid exiting the light energy density I lo ;
  • the photocurable material in the silo changes from a liquid state to a solid state.
  • the photometer's The optical density displayed on the display screen is maintained at a stable value, and this value is taken as the solid output light energy density Iso after the ultraviolet light passes through the thickness of the photocured material to be measured, and h is the height inside the silo, that is, the photocured material is full.
  • h is the thickness of the photocurable material after filling the silo.
  • the liquid absorbance and solid absorbance of the material in the present invention are different parameters and need to be measured separately.
  • the curing energy threshold proposed by the present invention refers to: during the curing process, the process of liquid to solid transformation does not occur at the beginning of illumination, and there is a period of cross-linking degree gradually between the beginning of the material being exposed to ultraviolet light and the generation of solid.
  • the stage of increasing but no solid appears, and the energy required for this stage is called the solidification threshold energy.
  • the solidification threshold time When the energy accumulates to this threshold energy, the solid appears, and the time required to reach this solidification threshold energy is called the solidification threshold time.
  • the optical density gradually weakens with the depth, so the energy accumulation also gradually weakens with the depth.
  • the present invention proposes a new definition of solidification depth: when the accumulated energy from a certain depth from the forming plane reaches the solidification threshold energy, it indicates that the liquid at this depth begins to transform into a solid, and the liquid before this depth reaches the threshold energy before the depth reaches the threshold energy. has been cured, so the depth just reaching the curing threshold energy is the curing depth of the liquid at this time.
  • the present invention directly and accurately obtains the DLP photocuring printing parameters of the material by simply testing the properties of the substance itself, including the liquid absorbance per unit thickness of the photocurable material, the solid absorbance per unit thickness and the curing threshold time, and avoids complexity and repetition. Multiple forming experiment tests save material, and the obtained working curve is more accurate than the working curve obtained by the traditional method.
  • the DLP printing parameters of the photocurable material can also be obtained through a simple test when the material composition changes, eliminating the need for repeated forming experiments. And because it does not depend on the mechanical properties of the material and other characteristics related to the properties after forming, for materials with weak mechanical properties and difficult to form, the method of the present invention can also be used to obtain accurate printing parameters, and then perform printing control.
  • Fig. 1 is the schematic diagram of light-cured material absorbance testing instrument in the present invention
  • Fig. 1 (a) is the external perspective view of the photocurable material absorbance testing instrument in the present invention
  • Fig. 1(b) is a half-section perspective view of a light-curing material absorbance testing instrument in the present invention
  • FIG. 2 is a schematic diagram of the light-curing material absorbance test process in the present invention.
  • Fig. 2 (a) is the schematic diagram of incident optical density test of the present invention.
  • Figure 2 (b) is a schematic diagram of the liquid exit optical density test of the present invention.
  • Figure 2 (c) is a schematic diagram of the solid output optical density test of the present invention.
  • FIG. 3 shows the data to be measured in the method for obtaining DLP photocuring printing parameters and the selection method of the preferred concentration range of the light absorber.
  • the serial number in the picture 1. UV ultraviolet light; 2. The transparent upper end cover of the silo; 3. The silo wall; 4. The transparent lower end cover of the silo; 5. The photometer measuring head; 6. The photometer test surface; Empty state; 8. The silo is filled with the light-cured liquid to be tested; 9. The silo is filled with the solid state of the light-cured liquid to be tested; 10. The photometer display screen;
  • Figure 3(a) Schematic diagram of the results of opto-rheological testing and the method for obtaining the curing threshold time by opto-rheological testing; Figure 3(b).
  • UV ultraviolet light 1, silo transparent upper end cover 2, silo wall 3, silo transparent lower end cover 4, photometer measuring head 5.
  • the incident optical density I i test first make the airtight silo composed of the transparent upper end cover 2 of the silo, the silo wall 3, and the transparent lower end cover 4 of the silo to be in an empty state 7, Then, the UV ultraviolet light 1 is vertically injected into the transparent upper end cover 2 of the silo, passes through the enclosed space of the silo wall 3, passes through the transparent lower end cover 4 of the silo, and reaches the photometer test surface 6 of the photometer measuring head 5, where the photometer The reading read out by the display screen 10 is recorded as the incident optical density I i ;
  • the liquid exit optical density I lo test adding the photocurable material in the liquid state to be tested is composed of the transparent upper end cover 2 of the silo, the wall 3 of the silo, and the transparent lower end cover 4 of the silo.
  • the closed silo make it in the state where the silo is filled with the light-cured liquid to be measured 8, and then make the UV ultraviolet light 1 vertically enter the transparent upper end cover 2 of the silo, and pass through the light in the liquid state surrounded by the silo wall 3.
  • the solidified material reaches the photometer test surface 6 of the photometer measuring head 5 after passing through the transparent lower end cover 4 of the silo, and the reading read out on the photometer display screen 10 is recorded as the liquid exit optical density Ilo ;
  • the solid exit optical density Iso test this step is carried out in step 3, and the UV ultraviolet light 1 irradiates the photocurable material in the liquid state so that the photocurable material in the liquid state changes from the liquid state to the solid state. The state changes, and finally reaches the solid state 9 in which the bin is filled with the light-cured liquid to be tested and solidified.
  • the reading on the photometer display screen 10 is stable, the reading is recorded as the solid exit optical density Iso .
  • the thickness of the silo wall is h, and the thickness of the light-cured material in the liquid state that fills the silo is h, which is also the thickness of the light-cured material in the solid state.
  • the data for accurate prediction of the actual forming layer thickness can be obtained by adjusting the concentration of the light absorber.
  • R sl ' represents the theoretically predicted value of the solid-liquid absorbance ratio
  • a 1 represents the slope of the linear fit data of solid absorbance per unit thickness and light absorber concentration
  • a 2 represents the linear fit of liquid absorbance per unit thickness and light absorber concentration Slope of the data
  • b 1 represents the intercept of the linear fit data representing solid absorbance per unit thickness and light absorber concentration
  • b 2 represents the intercept of the linear fit data representing liquid absorbance per unit thickness and light absorber concentration, respectively
  • c d Indicates the light absorber concentration.
  • the number of measurement points of the solid-liquid absorbance ratio can be increased. Since only the equipment shown in Figure 1 needs to be used for feeding and irradiation, the experimental amount is much smaller than that of the forming experiment, and the amount of material is also much smaller than the traditional forming experiment.
  • the photocurable material to be tested is prepared according to the preferred concentration range of the light absorber, and an opto-rheological test is carried out. It should be noted that the optical density on the opto-rheology test platform and the optical density on the forming surface of the DLP photo-curing platform should be adjusted to the same level before the test.
  • the results of the opto-rheological test are shown in Fig. 3(a), as the exposure time of the material to UV light increases, the storage modulus of the material appears as a continuous line in Fig. 3(a). The sudden rise of , and the dissipative modulus are crossed by the dotted line in Fig. 3(a).
  • intersection point corresponds to the gel point of the material, that is, the starting point for the photocurable material to transition from a liquid state to a solid state
  • the corresponding exposure time is the time when the material accumulates energy and begins to transition from liquid to solid, that is Cure threshold time t T .
  • step 1 the preferred concentration range of the light absorbing agent in the material is confirmed and the corresponding solid absorbance A s per unit thickness and liquid absorbance A l per unit thickness are measured, and the curing threshold time t of the material is measured in step 2 T , this three values are introduced into the theoretical model of the present invention:
  • t H is the exposure time corresponding to the cured H thickness and e is the natural logarithm.
  • the required printing curing thickness H is substituted into the single-layer curing model to obtain the exposure time t H , so as to realize DLP printing control.
  • the traditional method to determine the control parameters of DLP printing adopts the method of forming experiment, which needs to consume a lot of material to obtain the solidified thickness at a certain forming time, and uses discrete data points to fit the relationship between exposure time and forming thickness.
  • This method Relying on material shaping to have an accurately measurable structure, and the degree of accuracy depends on a large number of discrete data points, such a test method wastes material and is not straightforward enough.
  • the invention adds the liquid absorbance per unit thickness of the material itself, the solid absorbance per unit thickness and the curing threshold time to obtain the relationship between the exposure time and the curing thickness, which can obtain a more accurate relationship and save materials.
  • the error between the actual forming results and the theoretical prediction results is eliminated by adding a light absorbing agent, and the preferred concentration range of the light absorbing agent is obtained by comparing the change trend of the measured value of the solid-liquid absorbance ratio with the theoretical predicted value, which also improves the acquisition rate.
  • the accuracy of the parameters that control DLP printing saves materials and improves efficiency.
  • the material property parameters involved in the present invention have nothing to do with the mechanical properties of the material, which is not easy for the mechanical properties to be poor, and the forming is not easy, and the soft materials that cannot obtain the relationship between exposure time and forming thickness by forming experiments can also use the method of the present invention. Obtain precise exposure time versus forming thickness.

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Abstract

本发明公开了一种基于光固化材料吸光度性质的DLP打印控制方法。将光吸收剂加入到光固化材料中进行DLP打印，测试光固化材料在不同光吸收剂浓度情况下的单位厚度的液体和固体吸光度，求比值作为实际的固液吸光度比，并和固液吸光度比的理论预测值进行比较，获得实际的光固化材料中光吸收剂所选浓度；测定光固化材料的固化阈值时间，将光固化材料的单位厚度的固体吸光度、单位厚度的液体吸光度和固化阈值时间带入单层固化模型中，处理获得曝光时间tT和固化厚度H的关系；对于待测情况，输入固化厚度获得曝光时间进行DLP打印控制。本发明能准确获得材料的DLP光固化打印参数，避免了复杂且重复多次的成形实验测试，节省材料更精确。

Description

一种基于光固化材料吸光度性质的DLP打印控制方法 技术领域
本发明属于增材制造技术领域的一种打印控制方法，具体涉及一种通过光固化材料的吸光度性质获得光固化材料的DLP打印参数进而控制打印的方法。
背景技术
DLP(Digital light procession)全称是“数字光处理”技术。基于DMD芯片反射紫外光的成像原理，以光敏树脂为原料，携带有图形信息的UV紫外光将处于液体状态的光敏树脂转变为具有一定厚度的固体，重复多次单层成形从而形成立体模型。确定一个准确的曝光时间和成形厚度的关系决定了一个好的DLP光固化技术成形结果。
传统的确定曝光时间和成形厚度的关系的方法，是通过对光固化材料曝光一系列时间，获得其对应的固化厚度，由于使用“Beer-Lambert”定律可知这一关系的基本函数形式，则可根据实验测得的多个“时间—层厚”数据拟合得到曝光时间和成形厚度的关系曲线，从而获得任意希望固化层厚所对应的曝光时间。
这一方法存在明显不足，主要体现在几个方面：
1.精确的数据拟合需要较多的“时间—层厚”数据点，则需要消耗较多材料用于成形实验进行测试，对于材料有较多浪费，且还伴随对成形结构的测量及计算，不直接也步骤较多。
2.材料组分发生变化，成形实验就需要重新测试，成形实验的数据结果没有可扩展性，增加材料的浪费。
3.对于机械性质较软的材料，用于测量层厚的模型较难成形，很难精确获得成形层厚，无法准确获得“时间——层厚”数据点，影响了较软材料的精确成形。
发明内容
针对现有技术中的问题，为了解决背景技术中存在的问题，本发明主要提供一种控制DLP打印的方法，根据光固化材料本身的性质，引入了光固化材料的单位厚度的固体吸光度、单位厚度的液体吸光度和固化阈值时间，建立了一种全新的基于能量积累的单层固化模型，据此获得曝光时间和成形厚度的关系，并通过引入固液吸光度比作为评价标准，校准实际成形厚度和理论预测成形厚度的误差，获得准确的工作曲线，避免重复多次成形实验测试，避免材料的浪 费，并且提升曝光时间与层厚关系预测的准确性，进而精确控制打印过程。
为了实现上述目的，本发明包括以下技术方案：
本发明基于光固化材料吸光度性质对DLP打印进行控制分六步进行实现：
将光吸收剂加入到光固化材料中，再利用加入光吸收剂后的光固化材料进行光照固化进行DLP打印，打印过程中采用以下方式进行处理：
1)测试光固化材料在加入光吸收剂后、且改变不同光吸收剂浓度情况下的单位厚度的液体吸光度A l和单位厚度的固体吸光度A s；改变光吸收剂浓度，光固化材料透光度改变，光固化材料厚度会改变。
2)求得随光吸收剂浓度改变对应的单位厚度的液体吸光度A l和单位厚度固体吸光度A s之间的比值作为实际的固液吸光度比R sl：
R sl＝A s/A l
3)然后将实际的固液吸光度比和固液吸光度比的理论预测值进行比较：
若实际的固液吸光度比与固液吸光度比的理论预测值的差值达到固液吸光度比的理论预测值的10％以上，则认为实际的固液吸光度偏离固液吸光度比的理论预测，将偏离的实际的固液吸光度比对应的光吸收剂浓度区间选为实际的光固化材料中光吸收剂所选浓度；
4)光流变学测试测定步骤3中确定了光吸收剂浓度的光固化材料的固化阈值时间t T；
具体的，材料的固化阈值时间t T采用光流变学测试进行试验获得。
具体的，通过光流变测试获得固化阈值时间，采用本发明所述的方法获得材料的单位厚度固体吸光度和单位厚度液体吸光度，将这些参数加入本发明提出的理论数值模型中，即可获得对应材料的DLP打印的打印参数。
5)将光固化材料的单位厚度的固体吸光度、单位厚度的液体吸光度和对应的固化阈值时间带入本发明提出的以下建立的单层固化模型中，处理获得曝光时间t H和固化厚度H的关系：
Figure PCTCN2020112094-appb-000001
其中，t T表示固化阈值时间，H表示固化厚度，e表示自然常数；
6)在实际打印中，将所需打印的固化厚度H代入单层固化模型中处理获得曝光时间t H，按照曝光时间t H实现DLP打印控制。
本发明提出的单层固化模型是一种基于光能量光固化模型，包含了单位厚度的液体吸光度和固体吸光度和固化能量阈值。
固化能量阈值为固化的能量存在临界值，光照到固定的固化深度的光能量积累达到固化能量阈值时，该深度表示的就是固化的深度，液体固化为固体。随着深度的增加，光能量密度减少，能量积累减少。固化能量阈值为固化阈值时间乘以能量密度获得。
所述3)中的固液吸光度比的理论预测值R sl'采用以下公式计算：
Figure PCTCN2020112094-appb-000002
其中，R sl'表示固液吸光度比的理论预测值，a 1表示单位厚度的固体吸光度和光吸收剂浓度关系的线性拟合数据的斜率，a 2表示单位厚度的液体吸光度和光吸收剂浓度关系的线性拟合数据的斜率，b 1表示单位厚度的固体吸光度和光吸收剂浓度关系的线性拟合数据的截距、b 2分别表示表示单位厚度的液体吸光度和光吸收剂浓度关系的线性拟合数据的截距，c d表示光吸收剂浓度。具体实施中，a1,b1,a2,b2根据测试所得的单位厚度吸光度与光吸收剂浓度的数值点拟合得到。
具体的，改变光固化材料中光吸收剂浓度获得单位厚度固体吸光度和单位厚度液体吸光度的比值相较于光吸收剂浓度的函数关系。
本发明首次在DLP光固化过程中提出固体吸光度，针对本发明方法，首先本发明使用图1所示的吸光度测试仪进行测试获得。
所述1)中的单位厚度的液体吸光度A l和单位厚度的固体吸光度A s使用本发明的吸光度测试仪器进行测试获得；所述吸光度测试仪器包括料仓透明上端盖、料仓壁、料仓透明下端盖，料仓透明上端盖和料仓透明下端盖之间通过料仓壁连接，由此料仓透明上端盖、料仓壁和料仓透明下端盖共同组成一个密封的料仓，料仓透明上端盖上方设有UV紫外光，料仓下方设有光度计，光度计和显示屏连接。在测试的时候，光固化材料充满料仓作为待测物。
使用吸光度测试仪器进行测试的测试过程如下：
在料仓中不放置物质时，料仓为空仓，UV紫外光从料仓透明上端盖上方上部垂直射入料仓内，料仓之下的光度计在自身的感光位置接受透过空料仓之后的紫外光，在光度计的显示屏上显示的光密度作为入射光密度I i；
之后，将料仓中放入待测的光固化材料，光固化材料充满料仓作为待测物，UV紫外光从料仓透明上端盖上方上部垂直射入料仓内，料仓之下的光度计在自身的感光位置接受透过光固化材料之后的紫外光，在光度计的显示屏上初始显示的光密度作为紫外光经过厚度液体出射光能量密度I lo；
接着，在UV紫外光发出的紫外光不断照射开始之后，由于光固化材料开 始从液体向固体转变，在料仓中的光固化材料从液体状态转变到固体状态，随着时间推移，光度计的显示屏显示的光密度稳定保持在一个数值，此时该数值作为紫外光经过厚度的待测光固化材料后的固体出射光能量密度I so，h为料仓内部的高度，即光固化材料充满料仓后的厚度；
最后根据以下公式处理获得单位厚度的液体吸光度A l和单位厚度的固体吸光度A s：
Figure PCTCN2020112094-appb-000003
Figure PCTCN2020112094-appb-000004
其中，h为光固化材料充满料仓后的厚度。
本发明中材料的液体吸光度和固体吸光度是不同的参数，需要分别测量。
具体的，本发明提出的固化能量阈值是指：在固化过程中，液体向固体转变的过程并不是在光照开始时发生，材料从开始被紫外光照到产生固体之间是有一段交联度逐渐增加但不出现固体的阶段，而这个阶段所需的能量称为固化阈值能量，当能量积累到这个阈值能量时固体出现，到达这个固化阈值能量所需的时间称为固化阈值时间。
具体的，根据“Beer-Lambert”定律，光密度随深度逐渐减弱，所以能量积累也是随深度逐渐减弱。本发明提出全新的对固化深度的定义：当从成形平面开始的某深度积累的能量达到固化阈值能量，表明这个深度的液体开始转变成固体，而该深度前的液体在该深度达到阈值能量前已固化，所以刚达到固化阈值能量的深度就是此时液体的固化深度。
本发明的有益效果是：
本发明通过简单的物质本身性质的测试，包括光固化材料的单位厚度的液体吸光度和单位厚度的固体吸光度以及固化阈值时间，直接且准确的获得材料的DLP光固化打印参数，避免了复杂且重复多次的成形实验测试，节省材料，且得到的工作曲线较传统方法所得的工作曲线更精确。
由于基于材料本身的吸光度和光能量性质，在材料组分发生改变的情况下，也可以通过简单的测试获知光固化材料的DLP打印参数而省去了重复多次的成形实验。且由于并不依赖于材料的力学性质等和成形后的性质相关的特征，对于力学性质较弱的，不易成形的材料也可以采用本发明的方法获得精确的打印参数，进而进行打印控制。
附图说明
图1为本发明中光固化材料吸光度测试仪器示意图；
图1(a)为本发明中光固化材料吸光度测试仪器外部立体图；
图1(b)为本发明中光固化材料吸光度测试仪器半剖立体图；
图2为本发明中光固化材料吸光度测试过程示意图；
图2(a)为本发明入射光密度测试示意图；
图2(b)为本发明液体出射光密度测试示意图；
图2(c)为本发明固体出射光密度测试示意图；
图3为获得DLP光固化打印参数的方法中需要测量的数据及光吸收剂优选浓度区间的选择方式。
图中序号：1.UV紫外光；2.料仓透明上端盖；3.料仓壁；4料仓透明下端盖；5.光度计测量头；6.光度计测试面；7.料仓为空的状态；8.料仓中充满被测光固化液体状态；9.料仓中充满被测光固化液体固化后的固体状态；10.光度计显示屏；
图3(a).光流变测试的结果示意图以及通过光流变测试获得固化阈值时间的方法；图3(b).基于固液吸光度比的选择光吸收剂优选浓度区间的方法的示意图。
具体实施方式
为使本发明所提到的技术、设备的目的、优点等更加清楚，以下结合实施例及附图对本发明的技术、设备做进一步说明。
结合具体实施方法及附图，详细介绍实行该方法的具体步骤：
所述的单位厚度的吸光度，包括单位厚度的液体吸光度A l和单位厚度的固体吸光度A s的测试方法，结合附图实施的具体步骤：
1、根据图1所示的顺序安排放置，从上至下分别是UV紫外光1、料仓透明上端盖2、料仓壁3、料仓透明下端盖4、光度计测量头5。
2、如图2(a)所示，入射光密度I i测试：首先使得由料仓透明上端盖2、料仓壁3、料仓透明下端盖4组成的密闭的料仓处于空仓状态7，之后使得UV紫外光1垂直射入料仓透明上端盖2，穿过料仓壁3包围空间，透过料仓透明下端盖4后到达光度计测量头5的光度计测试面6，在光度计显示屏10读出的读数，记做入射光密度I i；
3、如图2(b)所示，液体出射光密度I lo测试：将待测的液体状态的光固化材料加入由料仓透明上端盖2、料仓壁3、料仓透明下端盖4组成的密闭的料仓中，使其处于料仓中充满被测光固化液体状态8，之后使得UV紫外光1垂直 射入料仓透明上端盖2，穿过料仓壁3包围的液体状态的光固化材料，透过料仓透明下端盖4后到达光度计测量头5的光度计测试面6，在光度计显示屏10读出的读数，记做液体出射光密度I lo；
4、如图2(9)所示，固体出射光密度I so测试：该步骤接步骤3进行，UV紫外光1照射液体状态的光固化材料会使得液体状态的光固化材料由液体状态向固体状态转变，最终达到料仓中充满被测光固化液体固化后的固体状态9，待光度计显示屏10上读数稳定，此时读数记做固体出射光密度I so。
5、使用如下公式计算这一待测光固化材料的单位厚度的液体吸光度Al和单位厚度的固体吸光度As：
Figure PCTCN2020112094-appb-000005
Figure PCTCN2020112094-appb-000006
其中料仓壁的厚度是h，充满料仓的液体状态的光固化材料的厚度就是h，也是固体状态的光固化材料的厚度。
由于预测成形层厚和实际成形层厚存在偏差，通过调整光吸收剂浓度来得到对实际成形层厚准确预测的数据，而作为优选的光吸收剂浓度范围选择方法结合附图实施的具体步骤：
调整待测光固化材料中添加的光吸收剂的浓度，按照上述单位厚度吸光度测试方法测量不同浓度光吸收剂下，材料的单位厚度的液体吸光度A l和单位厚度的固体吸光度A s，得到一系列“吸光度—光吸收剂浓度”的关系的数据点。使用Origin数学处理软件对单位厚度的液体吸光度A l和光吸收剂浓度c d的数据以及单位厚度的固体吸光度A s和光吸收剂浓度c d分别进行线性拟合，将拟合的关系式做比：
Figure PCTCN2020112094-appb-000007
其中R sl'表示固液吸光度比的理论预测值，a 1表示单位厚度的固体吸光度和光吸收剂浓度的线性拟合数据的斜率，a 2表示单位厚度的液体吸光度和光吸收剂浓度的线性拟合数据的斜率，b 1表示单位厚度的固体吸光度和光吸收剂浓度的线性拟合数据的截距，b 2分别表示表示单位厚度的液体吸光度和光吸收剂浓度的线性拟合数据的截距，c d表示光吸收剂浓度。据此求得固液吸光度比的理论预测值，如图3(b)中曲线所示。将根据实际的测量值所得的固液吸光度比的数 值点与理论预测值对比，如图3(b)所示，会有一部分的实际的固液吸光度比的数值偏离固液吸光度比的理论预测值，若实际的固液吸光度比与固液吸光度比的理论预测值的差值达到固液吸光度比的理论预测值的10％以上，则认为实际的固液吸光度比的数值偏离固液吸光度比的理论预测值，将偏离的实际的固液吸光度比对应的光吸收剂浓度区间选为实际的光固化材料中光吸收剂的优选浓度区间。为了得到更为精确的浓度优选区间，可增加固液吸光度比的测量点数，由于只需要使用图1中设备进行加料并照射，实验量远小于成形实验，材料用量也远小于传统的成形实验。
在确定了图3(b)中的光吸收剂优选浓度区间后，根据光吸收剂浓度优选区间制备需要测试的光固化材料，进行光流变学测试。需要注意的是，测试前应该将光流变学测试平台上的光密度与DLP光固化平台成形面处的光密度调整至统一。光流变学测试的结果如图3(a)所示，随着UV紫外光对材料的曝光时间增加，材料的储能模量如图3(a)中的连续线所示会出现模量的突然升高，并和耗散模量如图3(a)中虚线所示进行交叉。交叉点所对应的就是材料的凝胶点，也就是光固化材料从液体状态开始向固体状态转变的起始点，其所对应的曝光时间就是材料积累能量开始出现液体向固体转变的时间，也就是固化阈值时间t T。
在步骤1中确认了材料中光吸收剂的优选浓度区间并测得其对应的单位厚度的固体吸光度A s及单位厚度的液体吸光度A l，以及步骤2中测得该材料的固化阈值时间t T，将此三值引入本发明的理论模型中：
Figure PCTCN2020112094-appb-000008
其中t H是固化H厚度对应的曝光时间，e是自然对数。
在实际打印中，将所需打印的固化厚度H代入单层固化模型中处理获得曝光时间t H，以此实现DLP打印控制。
传统方法确定DLP打印的控制参数采用成形实验的方法，需要消耗很多材料来在确定的成形时间下的固化厚度，并使用离散的数据点来拟合获得曝光时间和成形厚度的关系，这一方法依赖材料成形具有准确的可测量的结构，且精确程度依赖于较多的离散数据点，这样的测试方法浪费材料也不够直接。
本发明加入了材料本身性质的单位厚度的液体吸光度，单位厚度的固体吸光度及固化阈值时间求得曝光时间和固化厚度的关系，能够获得更准确的关系，并节省材料。通过加入光吸收剂消除实际成形结果和理论预测结果之间的误差，而且通过比较固液吸光度比的实测值和理论预测值的变化趋势，求得光吸收剂 的优选浓度区间，也提高了获得的控制DLP打印的参数的准确性，节省了材料，提高了效率。
且本发明所涉及的物质性质参数和材料的力学性质无关，这对于力学性质较差，成形比较不容易，不能使用成形实验获得曝光时间和成形厚度关系的软材料也可以使用本发明的方法来获得精确的曝光时间和成形厚度的关系。

Claims (4)

  1. 一种基于光固化材料吸光度性质的DLP打印控制方法，其特征在于：将光吸收剂加入到光固化材料中，再利用加入光吸收剂后的光固化材料进行光照固化进行DLP打印，打印过程中采用以下方式进行处理：
    1)测试光固化材料在加入光吸收剂后、且改变不同光吸收剂浓度情况下的单位厚度的液体吸光度A l和单位厚度的固体吸光度A s；
    2)求得随光吸收剂浓度改变对应的单位厚度的液体吸光度A l和单位厚度固体吸光度A s之间的比值作为实际的固液吸光度比R sl：
    R sl＝A s/A l
    3)然后将实际的固液吸光度比和固液吸光度比的理论预测值进行比较：
    若实际的固液吸光度比与固液吸光度比的理论预测值的差值达到固液吸光度比的理论预测值的10％以上，则认为实际的固液吸光度偏离固液吸光度比的理论预测，将偏离的实际的固液吸光度比对应的光吸收剂浓度区间选为实际的光固化材料中光吸收剂所选浓度；
    4)光流变学测试测定步骤3中确定了光吸收剂浓度的光固化材料的固化阈值时间t T；
    5)将光固化材料的单位厚度的固体吸光度、单位厚度的液体吸光度和固化阈值时间带入以下建立的单层固化模型中，处理获得曝光时间t H和固化厚度H的关系：
    Figure PCTCN2020112094-appb-100001
    其中，t T表示固化阈值时间，H表示固化厚度，e表示自然常数；
    6)在实际打印中，将所需打印的固化厚度H代入单层固化模型中处理获得曝光时间t H，按照曝光时间t H实现DLP打印控制。
  2. 根据权利要求1所述的一种基于光固化材料吸光度性质的DLP打印控制方法，其特征在于：
    所述3)中的固液吸光度比的理论预测值R sl'采用以下公式计算：
    Figure PCTCN2020112094-appb-100002
    其中，R sl'表示固液吸光度比的理论预测值，a 1表示单位厚度的固体吸光度和光吸收剂浓度关系的线性拟合数据的斜率，a 2表示单位厚度的液体吸光度和 光吸收剂浓度关系的线性拟合数据的斜率，b 1表示单位厚度的固体吸光度和光吸收剂浓度关系的线性拟合数据的截距、b 2分别表示表示单位厚度的液体吸光度和光吸收剂浓度关系的线性拟合数据的截距，c d表示光吸收剂浓度。
  3. 根据权利要求1所述的一种基于光固化材料吸光度性质的DLP打印控制方法，其特征在于：所述1)中的单位厚度的液体吸光度A l和单位厚度的固体吸光度A s使用吸光度测试仪器进行测试获得；所述吸光度测试仪器包括料仓透明上端盖(2)、料仓壁(3)、料仓透明下端盖(4)，料仓透明上端盖(2)和料仓透明下端盖(4)之间通过料仓壁(3)连接，由此料仓透明上端盖(2)、料仓壁(3)和料仓透明下端盖(4)共同组成一个密封的料仓，料仓透明上端盖(2)上方设有UV紫外光(1)，料仓下方设有光度计(5)，光度计(5)和显示屏(10)连接。
  4. 根据权利要求3所述的一种基于光固化材料吸光度性质的DLP打印控制方法，其特征在于：使用吸光度测试仪器进行测试的测试过程如下：
    在料仓中不放置物质时，料仓为空仓(7)，UV紫外光(1)从料仓透明上端盖(2)上方上部垂直射入料仓内，料仓之下的光度计(5)在自身的感光位置(6)接受透过空料仓之后的紫外光(1)，在光度计(5)的显示屏(10)上显示的光密度作为入射光密度I i；
    之后，将料仓中放入待测的光固化材料(8)，光固化材料(8)充满料仓作为待测物，UV紫外光(1)从料仓透明上端盖(2)上方上部垂直射入料仓内，料仓之下的光度计(5)在自身的感光位置(6)接受透过光固化材料(8)之后的紫外光(1)，在光度计(5)的显示屏(10)上初始显示的光密度作为紫外光经过厚度(h)液体出射光能量密度I lo；
    接着，在UV紫外光(1)发出的紫外光不断照射开始之后，由于光固化材料(8)开始从液体向固体转变，随着时间推移，光度计(5)的显示屏(10)显示的光密度稳定保持在一个数值，此时该数值作为紫外光经过厚度(h)的待测光固化材料(8)后的固体出射光能量密度I so；
    最后根据以下公式处理获得单位厚度的液体吸光度A l和单位厚度的固体吸光度A s：
    Figure PCTCN2020112094-appb-100003
    Figure PCTCN2020112094-appb-100004
    其中，h为光固化材料(8)充满料仓后的厚度。
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Citations (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP2006227221A (ja) * 2005-02-16 2006-08-31 Fuji Photo Film Co Ltd パターン形成材料、及びパターン形成装置並びにパターン形成方法
CN110370625A (zh) * 2019-07-12 2019-10-25 浙江大学 一种提升dlp光固化增材制造效率的方法

Family Cites Families (11)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DK2083992T3 (en) * 2006-11-10 2016-09-12 Envisiontec Gmbh Continuous, generative method and apparatus for the manufacture of a three-dimensional object
EP3479933A1 (en) * 2009-09-17 2019-05-08 Sciaky Inc. Electron beam layer manufacturing apparatus
CN102253400A (zh) * 2011-04-08 2011-11-23 李�雨 基于全波谱原理化学辐射剂量计及其检测方法
CN105082536B (zh) * 2015-06-26 2017-04-19 北京金达雷科技有限公司 一种光固化3d打印方法
US11101396B2 (en) * 2015-11-30 2021-08-24 The Regents Of The University Of California Complementary conjugated polyelectrolyte complexes as electronic energy relays
US10987856B2 (en) * 2015-12-21 2021-04-27 Wacker Chemie Ag Method and device for producing an object by using a 3D printing device
CN105943406B (zh) * 2016-05-19 2019-11-05 深圳长朗智能科技有限公司 口腔修复用3d打印复合材料及其制备和使用方法
CN106346775A (zh) * 2016-10-10 2017-01-25 西安科技大学 一种彩色dlp光固化3d打印系统及方法
CN107283825A (zh) * 2017-06-23 2017-10-24 壹千零壹号泰州自动化科技有限公司 一种基于dlp光固化的大幅面快速3d打印方法以及打印设备
US10597289B1 (en) * 2017-07-17 2020-03-24 Adam Woolley 3D printer, resin, and interconnect
CN111186133A (zh) * 2019-12-26 2020-05-22 杭州乐一新材料科技有限公司 一种sla与dlp结合的3d打印方法及打印装置

Patent Citations (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP2006227221A (ja) * 2005-02-16 2006-08-31 Fuji Photo Film Co Ltd パターン形成材料、及びパターン形成装置並びにパターン形成方法
CN110370625A (zh) * 2019-07-12 2019-10-25 浙江大学 一种提升dlp光固化增材制造效率的方法

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