Method for eliminating photocuring layer lines

Abstract

The invention provides a method for eliminating photocuring layer lines. The method comprises the following steps that a workpiece model is established through three-dimensional modeling software; according to the material requirement of a workpiece, adaptive light-cured high-precision resin is prepared; the three-dimensional model of the workpiece is imported into photocuring slicing software, 3D printing parameters are adjusted by changing the slicing process, and a model rough blank is prepared through photocuring high-precision resin additive; the surface of the rough model blank is cleaned, the rough model blank is placed on a spin coater, the rough model blank is evenly and rotationally coated with a layer of light-cured resin in the layer grain direction, and the film forming thickness is controlled by controlling the technological parameters of the spin coater; the formed part is placed in a curing box, and the model rough blank and the light-cured resin spin-coated on the model rough blank are subjected to secondary curing at the same time; and the formed part is subjected to trimming treatment. According to the method for eliminating the light-cured layer grains, the light-cured resin with a certain thickness is spin-coated on the layer grain surface, so that gaps of the layer grains are filled with the resin, and the spin-coating layer and the rough blank are tightly combined through a subsequent secondary curing process, so that the light-cured layer grains on the surface of the formed part can be eliminated.

Description

Technical Field

[0001] The invention relates to the technical field of photocuring additive manufacturing, and in particular to a method for eliminating photocuring layer lines. Background Art

[0002] Stereolithography 3D printing is a relatively mature additive manufacturing technology. By converting the three-dimensional model into different two-dimensional images, different materials such as photocurable resins, powdered resin ceramics, etc. are used as raw materials to finally form the required workpiece layer by layer. However, since the accuracy of the photocuring technology itself in the Z-axis direction is only a few microns to tens of microns, for those workpieces with large surface curvature, the accuracy of the photocuring equipment on the Z-axis often leaves "step"-like layer patterns on the workpiece surface, which greatly hinders the application of photocuring technology in the field of precision manufacturing. Therefore, it is of great significance to develop a new method to eliminate photocuring layer patterns. Summary of the invention

[0003] The technical problem to be solved by the present invention is to provide a method for eliminating photocuring layer lines. A certain thickness of photocuring resin is spin-coated on the layer line surface so that the resin fills the gaps between the layer lines. A subsequent secondary curing process is then performed to achieve a close bond between the spin-coated layer and the rough blank. This can eliminate the photocuring layer lines on the surface of the molded part, and effectively solve the application limitations of photocuring technology caused by the layer lines.

[0004] The technical solution of the present invention is as follows:

[0005] A method for eliminating light-cured layer lines comprises the following steps:

[0006] Step S1, establishing a workpiece model through three-dimensional modeling software;

[0007] Step S2, configuring an appropriate light-curable high-precision resin according to the material requirements of the workpiece;

[0008] Step S3, importing the three-dimensional model of the workpiece into the light-curing slicing software, adjusting the 3D printing parameters by changing the slicing process, and using the light-curing high-precision resin additive manufacturing in step S2 to prepare the three-dimensional model established in step S1 to obtain a rough model;

[0009] Step S4, cleaning the surface of the rough model, placing it on a spin coater, and evenly rotating and coating a layer of light-curing resin on the rough model along the layer direction, and controlling the film thickness by controlling the process parameters of the spin coater to achieve full coverage, no steps and no bubbles;

[0010] Step S5, placing the molded part obtained in step S4 in a curing box, so that the rough model and the light-curing resin spin-coated thereon are simultaneously subjected to secondary curing;

[0011] Step S6, trimming the molded part obtained in step S5.

[0012] Furthermore, in step S2, the light-curable high-precision resin includes the following components in parts by weight:

[0013] 60-80 parts of prepolymer, 10-20 parts of active diluent, 2-8 parts of photoinitiator, and 1-2 parts of auxiliary agent.

[0014] Furthermore, in step S3, the 3D printing parameters include exposure time, layer height and lifting rate.

[0015] Furthermore, in step S4, the light-curable resin spin-coated on the rough model has the same or similar composition as the light-curable high-precision resin used to prepare the rough model.

[0016] Furthermore, the spin coating speed is 500-9500 rpm, and the coating time is controlled at 3-60 s.

[0017] Furthermore, in step S5, the wavelength of ultraviolet light for secondary curing is 350-410 μm, and the curing time is 8-24 hours.

[0018] Furthermore, the secondary curing is divided into two stages. The first stage is the solidification process of the spin-coating liquid from liquid to solid, which lasts for 0.5-2 hours; the second stage is the process of eliminating the internal stress of the spin-coating liquid and the rough model.

[0019] Furthermore, the method further comprises step S7 of performing vacuum ion plating on the surface of the molded part after the trimming treatment.

[0020] Furthermore, in the vacuum ion plating process, the vacuum degree is controlled to be below 0.01 MPa.

[0021] Compared with the prior art, the method for eliminating light-cured layer lines provided by the present invention has the following beneficial effects:

[0022] In the traditional photocuring process, due to the limitation of layer height, visible layer lines will be left on the curved surface of the molded part. These step-shaped layer lines greatly hinder the application of photocuring technology in the field of precision manufacturing. The method for eliminating photocuring layer lines provided by the present invention is to spin-coat a certain thickness of photocuring resin on the layer line surface so that the resin fills the gaps between the layer lines, and then achieve a close combination between the spin-coated layer and the rough blank through a subsequent secondary curing process, thereby eliminating the photocuring layer lines on the surface of the molded part, and effectively solving the application limitations of photocuring technology caused by the layer lines. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] In order to more clearly illustrate the technical solutions in the embodiments of the present invention, the following briefly introduces the drawings required for use in the description of the embodiments. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without creative work.

[0024] Figure 1 It is a surface appearance diagram of the sample before and after spin coating of the photocurable resin in the method of the present invention. DETAILED DESCRIPTION

[0025] In order to enable those skilled in the art to better understand the technical solutions in the embodiments of the present invention and to make the above-mentioned objects, features and advantages of the present invention more obvious and understandable, the specific implementation modes of the present invention are further described below.

[0026] The endpoints and any values ​​of the ranges disclosed in this article are not limited to the precise ranges or values, and these ranges or values ​​should be understood to include close to these ranges or values. For numerical ranges, the endpoint values ​​of each range, the endpoint values ​​of each range and the individual point values, and the individual point values ​​can be combined with each other to obtain one or more new numerical ranges, which should be considered as specifically disclosed in this article.

[0027] This embodiment takes 3D printed lenses as an example to explain in detail the method for eliminating photocuring layer lines provided by the present invention.

[0028] A method for eliminating light-cured layer lines comprises the following steps:

[0029] Step S1, establishing a workpiece model through three-dimensional modeling software;

[0030] Specifically, according to the parameters of the eyeglass lens, such as the power, refractive index, and Abbe number, and considering the different process requirements in the actual production process, the required lens model is established through 3D modeling software. Generally speaking, the higher the refractive index, the smaller the Abbe number of the lens.

[0031] Step S2, configuring an appropriate light-curable high-precision resin according to the material requirements of the workpiece;

[0032] The photocurable high-precision resin includes the following components by weight: 60-80 parts of prepolymer, 10-20 parts of active diluent, 2-8 parts of photoinitiator, and 1-2 parts of additive. Specifically, based on the material requirements of the final lens, the factors affecting the precision of the resin are considered in terms of inherent shrinkage and thermal expansion and contraction during the curing process, and different types, components and ratios of prepolymers are selected to prepare high-precision resins suitable for photocurable additive manufacturing of lenses.

[0033] In this embodiment, the light-curable high-precision resin used to make lenses requires that the prepolymer has a small shrinkage rate during the curing process, and the prepolymer monomer is selected from one or more of methacrylate or polyurethane acrylate, the reactive diluent is selected from tripropylene glycol diacrylate or cyclotrihydroxypropane formal acrylate, the photoinitiator is selected from one of diacylphosphine oxide 819 or 2,4,6-trimethylbenzoyl-diphenylphosphine oxide, and the auxiliary agent is at least one of a defoamer, an inhibitor, a leveling agent or a dispersant. Specifically, the light-curable high-precision resin includes the following components by weight: 65 parts of prepolymer, 20 parts of reactive diluent, 6 parts of photoinitiator, and 2 parts of auxiliary agent.

[0034] Step S3, importing the established three-dimensional model of the lens into a light-curing slicing software such as CHITUBOX and TANGO, adjusting 3D printing parameters such as exposure time, layer height and lifting rate by changing the slicing process, and using the light-curing high-precision resin additive manufacturing in step S2 to prepare the three-dimensional model established in step S1 to obtain a rough model; when preparing the rough model, the accuracy in the Z-axis direction is 50-500um;

[0035] Step S4, cleaning the surface of the rough model, placing it on a spin coater, and evenly rotating and coating a layer of light-curing resin on the rough model along the layer direction to eliminate the step-like layer pattern, and controlling the film thickness by controlling the process parameters such as the rotation speed, time, and dripping amount of the spin coater to achieve the standard of full coverage, no steps, and no bubbles;

[0036] The light-curing resin spin-coated on the rough model has the same or similar composition as the light-curing high-precision resin used to prepare the rough model, which can ensure that the spin-coated layer has good interface contact with the mirror layer surface. In the spin-coating process, the spin-coating speed is 500-9500 rpm, and the coating time is controlled at 3-60s.

[0037] Step S5, placing the molded part obtained in step S4 in a curing box, so that the rough model and the light-curing resin spin-coated thereon are simultaneously subjected to secondary curing;

[0038] Specifically, the wavelength of the secondary curing ultraviolet light is 350-410μm, and the curing time is 8-24h. The curing process is mainly divided into two stages. The first stage is mainly the solidification process of the spin-coating liquid from liquid to solid, which takes 0.5-2h. The second stage is the process of eliminating the internal stress of the spin-coating liquid and the lens substrate. The second stage takes a relatively long time, and the curing time varies depending on the composition of the matrix resin. If the force inside the lens is uneven, it may cause a certain deformation of the lens, or cause edge collapse during the lens assembly process.

[0039] Step S6, trimming the molded part obtained in step S5 to trim the burrs of the lens so that the edge of the lens is smooth and beautiful;

[0040] Step S7, vacuum ion plating is performed on the surface of the molded part to meet the surface properties required by the lens. The vacuum degree is controlled below 0.01MPa, and the coating thickness is 100nm-50um. The coating thickness can control the light transmittance and reflectivity. The reflectivity determines the color of the reflection, and then determines the color of the film layer of the lens. The color of the lens after plating is the color reflected by the film layer. Therefore, the specific coating thickness is adjusted according to the actual needs of the lens.

[0041] See also Figure 1 , is a surface appearance diagram of a sample before and after spin coating of a photocurable resin in the method of the present invention, wherein Figure 1 a represents before spin coating of photocurable resin, Figure 1 b represents after spin coating of photocurable resin. Figure 1 It can be seen that the surface of the molded part after spin coating with photocurable resin is filled with resin and has a smoother surface than the sample without spin coating.

[0042] The method for eliminating photocuring layer lines provided by the present invention comprises the following steps: spin-coating a certain thickness of photocuring resin on the layer line surface so that the resin fills the gaps between the layer lines, and then a subsequent secondary curing process is used to achieve a close bond between the spin-coated layer and the rough blank, thereby eliminating the photocuring layer lines on the surface of the molded part, and effectively solving the application limitations of the photocuring technology caused by the layer lines.

[0043] The embodiments of the present invention are described in detail above, but the present invention is not limited to the described embodiments. For those skilled in the art, various changes, modifications, substitutions and variations made to these embodiments without departing from the principles and spirit of the present invention are still within the protection scope of the present invention.

Claims

1. A method for eliminating light-cured layer lines, characterized in that: The steps include: Step S1, establishing a workpiece model through three-dimensional modeling software; Step S2, configuring an appropriate light-curable high-precision resin according to the material requirements of the workpiece; Step S3, importing the three-dimensional model of the workpiece into the light-curing slicing software, adjusting the 3D printing parameters by changing the slicing process, and using the light-curing high-precision resin additive manufacturing in step S2 to prepare the three-dimensional model established in step S1 to obtain a rough model; Step S4, cleaning the surface of the rough model, placing it on a spin coater, and evenly rotating and coating a layer of light-curing resin on the rough model along the layer direction, and controlling the film thickness by controlling the process parameters of the spin coater to achieve full coverage, no steps and no bubbles; Step S5, placing the molded part obtained in step S4 in a curing box, so that the rough model and the light-curing resin spin-coated thereon are simultaneously subjected to secondary curing; Step S6, trimming the molded part obtained in step S5.

2. The method for eliminating light-cured layer lines according to claim 1, characterized in that: In step S2, the light-curable high-precision resin includes the following components in parts by weight: 60-80 parts of prepolymer, 10-20 parts of active diluent, 2-8 parts of photoinitiator, and 1-2 parts of auxiliary agent.

3. The method for eliminating light-cured layer lines according to claim 1, characterized in that: In step S3, the 3D printing parameters include exposure time, layer height and lifting rate.

4. The method for eliminating light-cured layer lines according to claim 1, characterized in that: In step S4, the light-curable resin spin-coated on the rough model has the same or similar composition as the light-curable high-precision resin used to prepare the rough model.

5. The method for eliminating light-cured layer lines according to claim 4, characterized in that: The spin coating speed is 500-9500 rpm, and the coating time is controlled at 3-60s.

6. The method for eliminating light-cured layer lines according to claim 1, characterized in that: In step S5, the wavelength of ultraviolet light for secondary curing is 350-410 μm, and the curing time is 8-24 hours.

7. The method for eliminating light-cured layer lines according to claim 6, characterized in that: The secondary curing is divided into two stages. The first stage is the solidification process of the spin-coating liquid from liquid to solid, which lasts for 0.5-2 hours. The second stage is the process of eliminating the internal stress of the spin-coating liquid and the rough model.

8. The method for eliminating light-cured layer lines according to any one of claims 1 to 7, characterized in that: The method further comprises step S7 of performing vacuum ion plating on the surface of the molded part after the trimming treatment.

9. The method for eliminating light-cured layer lines according to claim 8, characterized in that: In the vacuum ion plating process, the vacuum degree is controlled below 0.01MPa.

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