CN116175730A - An improved method and device for a roller scraper in a light-cured ceramic 3D printing paving material - Google Patents

Abstract

The invention provides an improved method and device for a roller scraper in a photo-cured ceramic 3D printing spreading material. An improved method of a roller doctor blade in a photo-cured ceramic 3D printing blanket comprises: s1, establishing a fluid domain geometric model of a roller scraper in the process of photocuring ceramic 3D printing spreading; s2, obtaining technological parameters; s3, setting a physical field, setting boundary conditions, dividing grids and setting a solver for the geometric model of the fluid domain according to the process parameters; s4, changing structural parameters of the roller scraper in the fluid domain geometric model for multiple times, and calculating respectively to obtain pressure values before a plurality of scrapers; s5, determining structural parameters of the scraper corresponding to the pressure value before the minimum scraper according to the pressure values before the plurality of scrapers. The proper position of the roller relative to the scraper is determined through analysis, so that the pressure before the scraper is reduced, the deformation of the solid is reduced, the manufacturing precision and the printing success rate of the printed parts are improved, and the research and development efficiency and the improvement efficiency of the roller scraper spreading device are improved.

Description

An improved method and device for a roller scraper in a light-cured ceramic 3D printing paving material

technical field

The invention relates to the technical field of 3D printing of light-cured ceramics, in particular to an improved method and device for a roller scraper in 3D printing of light-cured ceramics.

Background technique

Most of the traditional ceramic molding technologies rely on molds to produce corresponding ceramic parts, but the design and production of molds takes a lot of time and cost, and cannot achieve convenient and flexible production goals. And for complex ceramic parts, such as parts with fine structure and internal pores, it is currently impossible to quickly design corresponding molds, which limits the production of complex ceramic parts. It can be seen that traditional ceramic molding methods have been unable to meet the growing demand for complex ceramic parts in the fields of biomedicine and aerospace. In order to solve the limitations of traditional ceramic molding methods, researchers have proposed ceramic additive manufacturing, and have used ceramic additive manufacturing technology to complete the production of various ceramic products with complex structures. Among many ceramic additive manufacturing technologies, light-curing 3D printing stands out because of its high precision, good mechanical properties, and high density of ceramic products.

The principle of ceramic light-curing 3D printing is as follows: first, by controlling the laser to emit laser light downwards, selectively irradiating the uppermost ceramic photosensitive slurry in the material tank to complete the single-layer curing of ceramic materials; The tool recoats a layer of ceramic material on the solid surface, and proceeds to the next curing; repeat the above curing process until the final solid model is obtained.

From the above light curing process, it can be seen that the use of coating tools to spread the ceramic slurry is essential and very important, and it is also one of the key steps that directly restrict the printing accuracy and printing success rate.

In the preparation of ceramic slurry before photocuring printing, researchers tend to prepare high-viscosity ceramic slurry, because high-viscosity ceramic slurry has a certain self-supporting property during the printing process, and the shrinkage rate during degreasing and sintering smaller. However, due to its low fluidity and high viscosity, high-viscosity ceramics will exert a large force on the solid (solidified layer) below during the laying process, sometimes causing deformation and damage to the printed parts, resulting in The printing process was interrupted.

In order to deal with the above problems, existing technicians have proposed a plan to improve the material spreading process: the past material spreading device mainly uses a scraper alone, and the existing material spreading improvement scheme is developed around the device, not only using a scraper, but also A roller/screw (hereinafter collectively referred to as a roller) is added to the front end of the scraper. Placing a rotating roller at the front of the scraper can increase the fluidity of the slurry in front of the scraper, reduce the pressure on the scraper edge, and make the interlayer bonding of the printed part stronger, meeting the needs for the use of different viscosities of ceramic slurry. But the technical staff did not further explain the rotating speed, turning direction, diameter size, and installation position relative to the scraper of the roller. Rolls that are not the right size, direction of rotation or installed in the wrong position can exacerbate the stress of the laying process and have a negative impact. In the process of designing the roller scraper, there is a lack of certain technical support, or the structural improvement is relatively large, resulting in higher costs.

Existing patent 1: "A scraper system for actively controlling the viscosity of 3D printing ceramic slurry" (CN202210662790.4, CN114986654A): the scraping device and the roller located in the direction of travel of the scraping device, the slurry directly below the roller passes through The movement direction generated by the rotation of the roller is consistent with the scraping direction of the scraping device. The viscosity of the high-viscosity ceramic slurry is reduced by the rotating motion of the roller, so that the 3D printing equipment is no longer affected by the viscosity of the ceramic slurry, thereby improving the success rate of printing and the dimensional accuracy of the printed part, and the structural design of patent 1 can reduce scraping The pressure of the knife edge makes the bond between the layers of the printed part stronger, meeting the needs for the use of ceramic pastes with different viscosities.

The content analysis of patent 1 is as follows:

The roller is located in the traveling direction of the scraping device, specifically in the traveling direction of the scraper, and the traveling direction of the scraper is the laying direction of the scraping device. Through the transmission belt, the roller and the first motor on the slide plate device are kept in synchronous rotation, and the first motor is actively controlled to realize various rotation speeds of the roller, so that the slurry that passes through the roller can be sheared and thinned. Reduce the viscosity of the slurry when it is spread by the scraper to meet the requirement that the device can print with different viscosities.

The high-speed rotating roller makes the slurry in the surrounding area fluid, and the movement direction of the slurry directly under the roller is the same as that of the scraping device after the roller rotates, which will reduce the occurrence of this phenomenon The resistance of the slurry to the scraper finally reduces the pressure of the scraper to the slurry, thereby reducing the risk of the printed part being pushed down by the scraper during the printing process, so that the slurry can be spread onto the printing surface more smoothly.

The role of the roller is to assist the scraper, and it is necessary to reserve enough slurry to cover the scraper, so the distance between the roller and the printing platform is greater than the distance between the scraper and the printing platform.

Disadvantages of Patent 1: 1. The direction of rotation speed at the bottom of the roller is the same as the moving direction of the scraper. At this time, the role of the roller is only shear thinning to reduce the viscosity of the slurry before the scraper, but it does not fundamentally resist the movement of the scraper. The pressure in front of the knife, if you want to resist the pressure in front of the knife generated by the scraper, you must make the direction of the resistance to the left (and the value is smaller than the pressure in front of the knife); 2. "So the distance between the roller and the printing platform is greater than the distance between the scraper and the printing platform The distance between the rollers is slightly higher to prevent the introduction of greater roller force, but if the position is higher, the slurry that is closer to the surface of the solidified layer cannot be driven, so the installation position of the rollers is very important. Patent No. 1 Indicate the relevant size parameters and installation parameters of the roller.

Existing Patent No. 2: "A Paving System for 3D Printing Equipment" (CN201910136735.X, CN109702854A): Patent No. 2 discloses a paving system for 3D printing equipment. The paving system includes a paving device and a driving paving device The driving device and the support platform for supporting the paving device; the paving device includes: a supporting part, including two oppositely arranged support seats, with a certain distance between the two support seats; the support seat is connected with the driving device through a conveyor belt to Make the supporting part move under the drive of the driving device; the scraping part, the scraping part is in the shape of "Π", the scraping part extends along the direction perpendicular to the running of the supporting part, the scraping part is set on the outer periphery of the supporting part, and the scraping part The two ends of the part in its extending direction are respectively hinged with the two supporting seats, so that the opposite sides of the scraping part in the moving direction of the supporting part move up and down alternately, so as to realize the two-way scraping of the scraping part. The advantages are: the design structure of double scrapers can realize multiple forward and reverse double scraping coatings to improve printing efficiency; the design of grooved rollers and screws can improve the quality of slurry paving.

In Patent No. 2, the technicians chose a Π-shaped scraper, and selected a roller and a screw as auxiliary tools for spreading materials. The screw is mainly used for stirring to reduce the viscosity of the slurry, and the main function of the roller is to reduce the pressure generated at the front end of the scraper. The device is relatively novel, but the whole is relatively complicated. In the actual application process, if the relevant parameters of the roller and scraper can be well controlled, only the roller can be used without installing the screw, which simplifies the installation operation. At the same time, the introduction of the screw will bring The spreading force generated by the screw is not friendly enough for the spreading of high-viscosity slurry.

Disadvantages of Patent No. 2: 1. The installation parameters or reference opinions of the roller and the scraper are not given. The relative position of the two has a great influence on the force of the solid during the high-viscosity spreading process. If the adjustment is not good, it will have a negative effect. 2. The screw is introduced into the device, which is equivalent to introducing an extra force, which will affect the solid during the material spreading process. And it is more complicated in terms of mechanical design, mechanical installation, control, etc.

As shown in Figure 4 and Figure 5, only the scraper (inclined straight knife) will generate a large force at the front end of the scraper during the material spreading process. As shown in Figure 6, place a roller in front of the doctor blade. If the installation position and direction of the roller are not correct, the pressure in front of the blade will be increased (increased from 3500Pa to about 5500Pa).

The prior art does not give the structural parameters of the roller scraper. If the combined position of the roller scraper is unreasonable, it will have side effects on the material spreading process, increase the pressure in front of the knife, and increase the deformation of the solidified layer.

Contents of the invention

The technical problem to be solved by the present invention is to provide an improved method and device for a roller scraper in photo-cured ceramic 3D printing pavement for the deficiencies of the prior art.

The technical solution of the present invention to solve the above-mentioned technical problems is as follows: an improved method of roller scraper in 3D printing of light-cured ceramics, comprising:

S1. Establish the geometric model of the fluid domain of the roller scraper during the laying process of photocured ceramic 3D printing;

S2, obtaining process parameters;

S3. According to the process parameters, set the physical field, set the boundary conditions, divide the grid and set the solver for the geometric model of the fluid domain;

S4. Change the structural parameters of the roller scrapers in the geometric model of the fluid domain several times and calculate them respectively to obtain the pressure values before multiple scrapers;

S5. According to the multiple pressure values in front of the doctor blade, determine the structural parameter of the roller scraper corresponding to the smallest pressure value in front of the doctor blade.

The beneficial effect of adopting the technical solution of the present invention is: through analysis and determination of the appropriate position of the roller relative to the scraper, the roller scraper device is optimized according to the actual working conditions, so as to reduce the pressure in front of the knife, reduce the deformation of the solid, and improve the printing parts. Manufacturing accuracy and printing success rate can reduce research and development costs, save research and development time, and improve the efficiency of research and development and improvement of the roller scraper spreading device. It provides theoretical guidance for the structural design of the roller scraper, and simplifies the design process of the roller scraper device.

Further, the structural parameters of the roller and scraper in the geometric model of the fluid domain are the lateral distance between the roller and the scraper and the height between the roller and the solid.

The beneficial effect of adopting the above-mentioned further technical solution is that the structural parameters of the roller scraper are optimally designed from multiple angles, and the simulation accuracy is improved. Determine the proper position of the roller relative to the scraper through analysis, optimize the roller scraper device according to the actual working conditions, reduce the pressure in front of the knife, reduce the deformation of the solid, improve the manufacturing accuracy of the printed parts and the success rate of printing, and reduce the research and development Cost, save research and development time, improve the efficiency of research and development and improvement of roller scraper spreading device. It provides theoretical guidance for the structural design of the roller scraper, and simplifies the design process of the roller scraper device.

Further, the process parameters are the inclination angle of the scraper, the straight part of the scraper, the horizontal moving speed of the scraper, the height of the scraper from the solid, the viscosity of the ceramic material, the material density of the ceramic material, the contact angle of the ceramic material, the Surface tension, initial roller scraper structure parameters.

The beneficial effect of adopting the above further technical solution is that specific data can be set according to manufacturing requirements and process requirements. Set process parameters in many ways to improve simulation reliability and accuracy.

Further, the step of setting the physical field for the geometric model of the fluid domain is: selecting the phase field method, the laminar flow model method and the dynamic grid model method for the geometric model of the fluid domain to set the physical field.

The beneficial effect of adopting the above-mentioned further technical solution is: using the phase field method, laminar flow and moving grid equipment to restore the laying process of ceramic light-cured 3D printing, and the influence of the slurry before the knife is considered in the simulation model. Improve simulation reliability and improve accuracy.

Further, the laminar flow model method uses the N-S equation, and the phase field method is used to set the air domain and the slurry domain in the physical field.

The beneficial effects of adopting the above further technical solution are: improving simulation reliability and accuracy.

Further, the step of setting boundary conditions for the geometric model of the fluid domain is: setting the part in contact with the air as an open boundary, setting the scraper boundary as a moving mesh boundary, and setting the roller boundary as a wall moving.

The beneficial effect of adopting the above-mentioned further technical solution is that it is convenient to set boundary conditions for the geometric model of the fluid domain, improve simulation reliability and accuracy.

Further, dividing the grid for the geometric model of the fluid domain is automatically dividing the grid according to a preset maximum grid size, and the solver is a transient solver.

The beneficial effects of adopting the above-mentioned further technical solution are: improving automation, improving simulation reliability, and improving accuracy.

Further, step S3 includes:

S31. According to the process parameters, set the physical field, set the boundary conditions, divide the grid, and set the solver for the geometric model of the fluid domain to generate a calculation model;

S32. Perform fluid simulation calculation on the calculation model to obtain a simulation result;

S33. Judging whether the simulation result is converged;

S34. When the simulation result converges, execute step S3.

The beneficial effect of adopting the above-mentioned further technical solution is: setting the geometric model of the fluid domain and judging whether the simulation result converges, and performing subsequent steps when the convergence occurs, so as to improve the reliability and accuracy of the simulation.

Further, step S33 includes:

Get preset tolerances as well as actual results;

Calculate the relative error with the actual result according to the simulation result;

Judging whether the relative error is smaller than the preset allowable error;

When the relative error is smaller than the preset allowable error, it is judged that the simulation result converges.

The beneficial effect of adopting the above-mentioned further technical solution is: select the transient solver to solve, and when the final relative error is less than the allowable error, it is judged as convergent, and the pressure value generated under this model is recorded.

In addition, the present invention also provides an improved device for roller scrapers in photocured ceramic 3D printing materials, including: acquisition equipment and processing equipment, the acquisition equipment is connected to the processing equipment,

The processing equipment is used to establish the fluid domain geometric model of the roller scraper in the process of photocuring ceramic 3D printing material laying;

The acquisition device is used to acquire process parameters;

The processing equipment is also used to set the physical field, set the boundary conditions, divide the grid and set the solver for the geometric model of the fluid domain according to the process parameters;

The processing equipment is also used to change the structural parameters of the roller scrapers in the geometric model of the fluid domain multiple times and calculate them separately to obtain the pressure values before multiple scrapers;

The processing device is further configured to determine, according to the plurality of pressure values before the doctor blade, the structural parameter of the roller doctor blade corresponding to the minimum pressure value before the doctor blade.

The beneficial effect of adopting the technical solution of the present invention is: through analysis and determination of the appropriate position of the roller relative to the scraper, the roller scraper device is optimized according to the actual working conditions, so as to reduce the pressure in front of the knife, reduce the deformation of the solid, and improve the printing parts. Manufacturing accuracy and printing success rate can reduce research and development costs, save research and development time, and improve the efficiency of research and development and improvement of the roller scraper spreading device. It provides theoretical guidance for the structural design of the roller scraper, and simplifies the design process of the roller scraper device.

Advantages of additional aspects of the invention will be set forth in the description which follows, and in part will be obvious from the description, or may be learned by practice of the invention.

Description of drawings

Fig. 1 is one of the schematic flowcharts of the method for improving the roller scraper in the photocured ceramic 3D printing pavement provided by the embodiment of the present invention.

Fig. 2 is the second schematic flow chart of the improvement method of the roller scraper in the photocured ceramic 3D printing pavement provided by the embodiment of the present invention.

Fig. 3 is a schematic structural diagram of an improved device for a roller scraper in a photocurable ceramic 3D printing pavement provided by an embodiment of the present invention.

Fig. 4 is one of the fluid volume distribution diagrams during the laying process provided by the embodiment of the present invention.

Fig. 5 is one of the pressure distribution diagrams during the laying process provided by the embodiment of the present invention.

Fig. 6 is the second pressure distribution diagram during the laying process provided by the embodiment of the present invention.

Fig. 7 is the second diagram of the fluid volume distribution during the laying process provided by the embodiment of the present invention.

Fig. 8 is a schematic diagram of the relative position relationship of the roller scrapers provided by the embodiment of the present invention.

Fig. 9 is the third pressure distribution diagram during the material laying process provided by the embodiment of the present invention.

Explanation of reference numerals in the accompanying drawings: 1. Obtaining equipment; 2. Processing equipment; 3. Scraper; 4. Slurry; 5. Solidified; 6. Roller.

Detailed ways

The principles and features of the present invention are described below in conjunction with the accompanying drawings, and the examples given are only used to explain the present invention, and are not intended to limit the scope of the present invention.

As shown in Figure 1, an embodiment of the present invention provides an improved method for a roller scraper in photocured ceramic 3D printing materials, including:

S1. Establish the geometric model of the fluid domain of the roller scraper during the laying process of photocured ceramic 3D printing;

S2, obtaining process parameters;

S3. According to the process parameters, set the physical field, set the boundary conditions, divide the grid and set the solver for the geometric model of the fluid domain;

S4. Change the structural parameters of the roller scrapers in the geometric model of the fluid domain several times and calculate them respectively to obtain the pressure values before multiple scrapers;

S5. According to the multiple pressure values in front of the doctor blade, determine the structural parameter of the roller scraper corresponding to the smallest pressure value in front of the doctor blade.

The beneficial effect of adopting the technical solution of the present invention is: through analysis and determination of the appropriate position of the roller relative to the scraper, the roller scraper device is optimized according to the actual working conditions, so as to reduce the pressure in front of the knife, reduce the deformation of the solid, and improve the printing parts. Manufacturing accuracy and printing success rate can reduce research and development costs, save research and development time, and improve the efficiency of research and development and improvement of the roller scraper spreading device. It provides theoretical guidance for the structural design of the roller scraper, and simplifies the design process of the roller scraper device.

As shown in Figure 2, 1. Establish the geometric model of ceramic light-cured 3D printing materials; 2. Set physical parameters, boundary conditions, meshing, and set solvers according to manufacturing requirements and process parameters; 3. Change rollers and scrapers The lateral distance between the rollers and the distance between the solidified layer (solidified) and recalculate the simulation model; 4. Obtain the pressure value in front of the knife, find the law, and determine the better structural parameters.

Further, the structural parameters of the roller and scraper in the geometric model of the fluid domain are the lateral distance between the roller and the scraper and the height between the roller and the solid.

The beneficial effect of adopting the above-mentioned further technical solution is that the structural parameters of the roller scraper are optimally designed from multiple angles, and the simulation accuracy is improved. Determine the proper position of the roller relative to the scraper through analysis, optimize the roller scraper device according to the actual working conditions, reduce the pressure in front of the knife, reduce the deformation of the solid, improve the manufacturing accuracy of the printed parts and the success rate of printing, and reduce the research and development Cost, save research and development time, improve the efficiency of research and development and improvement of roller scraper spreading device. It provides theoretical guidance for the structural design of the roller scraper, and simplifies the design process of the roller scraper device.

Further, the process parameters are the inclination angle of the scraper, the straight part of the scraper, the horizontal moving speed of the scraper, the height of the scraper from the solid, the viscosity of the ceramic material, the material density of the ceramic material, the contact angle of the ceramic material, the Surface tension, initial roller scraper structure parameters.

The beneficial effect of adopting the above further technical solution is that specific data can be set according to manufacturing requirements and process requirements. Set process parameters in many ways to improve simulation reliability and accuracy.

Further, the step of setting the physical field for the geometric model of the fluid domain is: selecting the phase field method, the laminar flow model method and the dynamic grid model method for the geometric model of the fluid domain to set the physical field.

The beneficial effect of adopting the above-mentioned further technical solution is: using the phase field method, laminar flow and moving grid equipment to restore the laying process of ceramic light-cured 3D printing, and the influence of the slurry before the knife is considered in the simulation model. Improve simulation reliability and improve accuracy.

Further, the laminar flow model method uses the N-S equation, and the phase field method is used to set the air domain and the slurry domain in the physical field.

The beneficial effects of adopting the above further technical solution are: improving simulation reliability and accuracy.

Further, the step of setting boundary conditions for the geometric model of the fluid domain is: setting the part in contact with the air as an open boundary, setting the scraper boundary as a moving mesh boundary, and setting the roller boundary as a wall moving.

The beneficial effect of adopting the above-mentioned further technical solution is that it is convenient to set boundary conditions for the geometric model of the fluid domain, improve simulation reliability and accuracy.

Further, dividing the grid for the geometric model of the fluid domain is automatically dividing the grid according to a preset maximum grid size, and the solver is a transient solver.

The beneficial effects of adopting the above-mentioned further technical solution are: improving automation, improving simulation reliability, and improving accuracy.

Further, step S3 includes:

S31. According to the process parameters, set the physical field, set the boundary conditions, divide the grid, and set the solver for the geometric model of the fluid domain to generate a calculation model;

S32. Perform fluid simulation calculation on the calculation model to obtain a simulation result;

S33. Judging whether the simulation result is converged;

S34. When the simulation result converges, execute step S3.

The beneficial effect of adopting the above-mentioned further technical solution is: setting the geometric model of the fluid domain and judging whether the simulation result converges, and performing subsequent steps when the convergence occurs, so as to improve the reliability and accuracy of the simulation.

Further, step S33 includes:

Get preset tolerances as well as actual results;

Calculate the relative error with the actual result according to the simulation result;

Judging whether the relative error is smaller than the preset allowable error;

When the relative error is smaller than the preset allowable error, it is judged that the simulation result converges.

The beneficial effect of adopting the above-mentioned further technical solution is: select the transient solver to solve, and when the final relative error is less than the allowable error, it is judged as convergent, and the pressure value generated under this model is recorded.

The parameters such as the proper position and rotational speed of the roller relative to the scraper can be determined through analysis, which provides theoretical guidance for the structural design of the roller scraper and simplifies the design process of the roller scraper device. Only using rollers and scrapers to complete light-cured paving can reduce the pressure in front of the knife, reduce the deformation of solids, and improve the success rate of printing.

The improved method of the roller scraper in a light-cured ceramic 3D printing pavement provided by the present invention can be an improved method of a roller scraper device in a light-cured ceramic 3D print pavement based on CFD (computational fluid dynamics, computational fluid dynamics) technology, including : The first step: establish the geometric model of the fluid domain of the roller scraper during the material spreading process; the second step: set the boundary conditions and physical fields according to the material data and tool data obtained from the actual measurement, and divide the grid, and select the solution The device performs fluid simulation calculation on the established calculation model, enters the simulation analysis, and judges the convergence of the simulation results; the third step: changing the geometric parameters or process parameters in the model, mainly manifested in changing the lateral distance between the roller scraper roller and the scraper, The height between the roller and the solid, repeat the simulation calculation and analysis, and calculate the pressure data result of the target point; the fourth step: according to the data result, take the structural parameters when the pressure is minimum, including the lateral distance between the roller and the scraper, the roller and the solid height between solids.

It should be noted that parameter substitution: the simulation of the embodiment of the present invention is to optimize the distance between the roller and the scraper and the distance between the roller and the solid layer when other process and manufacturing parameters do not change. It can also optimize parameters such as the rotational speed of the roller and the diameter of the roller.

Specifically, 1. SolidWorks software can be used to establish a geometric model of the roller scraper laying process in ceramic light-curing 3D printing laying, and it can be imported into Comsol (COMSOL Multiphysics, multi-physics simulation software) for analysis.

It should be noted that from the perspective of software: Solidworks can be replaced by any 3D/2D software, and Comsol simulation software can be replaced by any other software that can simulate fluids. It is also possible to divide the mesh in the special meshing software instead of using Comsol's own meshing function.

2. Measure the selected scraper speed, size, and material in the actual paving process to modify the geometric model, set boundary conditions, and physical fields. For example, the parameters of the following experiments are: the scraper 3 is an oblique straight-faced blade (75° inclination, 0.4 mm straight face part, 20 mm/s horizontal movement speed, 0.5 mm height between the scraper and the solid), high-viscosity ceramic material (slurry 4) Power-law model, when the shear rate is 20s ^-1 , the viscosity is 30pa·s, the material density is 2740kg/m ³ , the contact angle is 60°, the surface tension is 0.03N/m, the diameter of the roller 6 is 7mm, the scraper and The roller gap is 7mm, and the height of the roller 6 from the solid 5 is 1.5mm. In actual application, specific data can be set according to manufacturing requirements and process requirements.

3. The physical field uses phase field method, laminar flow, and moving mesh, and the laminar flow model method uses N-S equation (Navier-Stokes, Navier-Stokes), including gravity. In the phase field method, the air domain and In the slurry domain, the interface thickness parameter is 0.1 mm, and the mobility adjustment parameter is 1.

4. In the boundary conditions, the part in contact with the air is selected as an open boundary. The boundary of the scraper is set as the boundary of the moving grid, and the speed is set to be horizontal at 20mm/s. The boundary of the roller is set to move at the wall, and the speed is set to 20mm/s. The rotation speed in the direction of the bottom is opposite to that of the scraper.

5. The maximum grid size of the grid design is 0.2mm, and the automatic grid division function is turned on.

6. Select a transient solver to solve, and when the final relative error is less than the allowable error, it is judged to be converged.

7. Record the pressure values generated under this model.

8. As shown in Figure 7 and Figure 8, change the geometric model, including the lateral distance between the roller and the scraper (7mm, 6mm, 5mm, 4mm, no stick), the height between the roller and the solid (1.5mm, 0.5mm, No roller), repeat the above steps, and select the parameter with the smallest pressure value.

Wherein, the arrow in Fig. 7 represents the rotation direction of the roller, and the inclination angle of the scraper can be 75 degrees.

The following results are obtained,

Table 1:

The correctness of the model can be verified by experiment number 9, and it is tested without adding rollers in the laboratory.

From the above results, it can be seen that when the roller height is 1.5mm, when the lateral distance is less than about 6mm, there will be a "squeeze effect" on the knife edge, that is, the lateral distance between the roller and the scraper should not be too close, otherwise the extrusion phenomenon will be obvious and will increase. If the pressure in front of the knife is a little far away, the rollers will be independent and cannot affect the pressure at the front end of the scraper.

In the case of a roller height of 1.5mm, when the lateral distance is less than about 5mm, there will be a "squeeze effect" on the knife edge; in the case of a roller height of 0.5mm, when the lateral distance is less than about 4mm, there will be a "squeeze effect" on the knife edge ", that is, the height of the roller should not be too high, otherwise it will not be able to reduce the pressure.

As shown in Figure 9, Figure 9 shows the pressure distribution when the distance between the scraper and the roller is 6 mm, and the distance between the roller and the solid layer is 0.5 mm. The material spreading direction is to the right, and the circle in the figure is the pressure area.

To sum up, in the case of certain other process parameters, such as the data of experiment No. 4 in Table 1, it is most appropriate to select the mechanism parameters with the distance between the scraper and the roller being 6mm and the distance between the roller and the solid layer being 0.5mm. The pressure at the front end of the scraper can be reduced from 3500Pa to 791Pa, and the pressure is reduced by 77.4%.

1. As mentioned above, according to the pressure in front of the knife calculated by simulation, the relative position and size relationship of the improved roller scraper 3 is obtained, which greatly improves the material spreading effect of the roller scraper and reduces the deformation of the solidified layer. Based on the specific The case shows that the optimized roller scraper can reduce the pressure in front of the knife by 77.4%.

2. Moreover, based on CFD technology, the improvement design cycle is greatly shortened, the design cost and experiment cost are reduced, and the pressure distribution in front of the knife is effectively improved without making major changes to the device structure.

3. In addition, CFD technology can be used to model the laying process of ceramic photocuring 3D printing. The error between the simulation calculation results and the measured data without rollers is controlled within 20%, which verifies the rationality of the model.

In a word, the present invention optimizes the parameter values of each dimension of the roller scraper, and has the advantages of little structural change and easy implementation.

The method of using CFD technology to optimize the roller scraper device is analyzed from a quantitative point of view. The phase field method, laminar flow and moving grid equipment are used to restore the laying process of ceramic photocuring 3D printing, and the influence of the slurry before the knife is considered in the simulation model. Using CFD to guide the design of the laying device for ceramic photo-curing 3D printing, it is convenient and fast to reduce the time for debugging and experimentation.

As shown in Figure 3, in addition, the present invention also provides an improved device for a roller scraper in a light-cured ceramic 3D printing pavement, including: an acquisition device 1 and a processing device 2, the acquisition device 1 and the processing device 2 connect,

The processing equipment is used to establish the fluid domain geometric model of the roller scraper in the process of photocuring ceramic 3D printing material laying;

The acquisition device is used to acquire process parameters;

The processing equipment is also used to set the physical field, set the boundary conditions, divide the grid and set the solver for the geometric model of the fluid domain according to the process parameters;

The processing equipment is also used to change the structural parameters of the roller scrapers in the geometric model of the fluid domain multiple times and calculate them separately to obtain the pressure values before multiple scrapers;

The processing device is further configured to determine, according to the plurality of pressure values before the doctor blade, the structural parameter of the roller doctor blade corresponding to the minimum pressure value before the doctor blade.

The beneficial effect of adopting the technical solution of the present invention is: through analysis and determination of the appropriate position of the roller relative to the scraper, the roller scraper device is optimized according to the actual working conditions, so as to reduce the pressure in front of the knife, reduce the deformation of the solid, and improve the printing parts. Manufacturing accuracy and printing success rate can reduce research and development costs, save research and development time, and improve the efficiency of research and development and improvement of the roller scraper spreading device. It provides theoretical guidance for the structural design of the roller scraper, and simplifies the design process of the roller scraper device.

Finally, it should be noted that: the above embodiments are only used to illustrate the technical solutions of the present invention, rather than limiting them; although the present invention has been described in detail with reference to the foregoing embodiments, those of ordinary skill in the art should understand that: It is still possible to modify the technical solutions described in the foregoing embodiments, or perform equivalent replacements for some or all of the technical features; and these modifications or replacements do not make the essence of the corresponding technical solutions deviate from the technical solutions of the various embodiments of the present invention. scope.

Claims (10)

1. An improved method for a roller scraper in a light-cured ceramic 3D printing pavement, characterized in that it comprises: S1. Establish the geometric model of the fluid domain of the roller scraper during the laying process of photocured ceramic 3D printing; S2, obtaining process parameters; S3. According to the process parameters, set the physical field, set the boundary conditions, divide the grid and set the solver for the geometric model of the fluid domain; S4. Change the structural parameters of the roller scrapers in the geometric model of the fluid domain several times and calculate them respectively to obtain the pressure values before multiple scrapers; S5. According to the multiple pressure values in front of the doctor blade, determine the structural parameter of the roller scraper corresponding to the smallest pressure value in front of the doctor blade. 2. The improved method of the roller scraper in a kind of light curing ceramic 3D printing material according to claim 1, characterized in that, the roller scraper structural parameters in the geometric model of the fluid domain are the lateral distance between the roller and the scraper and the roller scraper. and the height between already solid. 3. The improved method of a roller scraper in a light-cured ceramic 3D printing pavement according to claim 1, wherein the process parameters are the inclination angle of the scraper, the straight part of the scraper, the horizontal moving speed of the scraper, and the scraper The height from the solid, the viscosity of the ceramic material, the material density of the ceramic material, the contact angle of the ceramic material, the surface tension of the ceramic material, and the structural parameters of the initial roller scraper. 4. The improved method of a roller scraper in a light-cured ceramic 3D printing pavement according to claim 1, wherein the step of setting the physical field for the geometric model of the fluid domain is: The model adopts the phase field method, the laminar flow model method and the dynamic grid model method to set the physical field. 5. the improved method of the roller scraper in a kind of light-cured ceramic 3D printing paving material according to claim 4, it is characterized in that, described laminar flow mode method selects N-S equation for use, selects the air in the physical field to set by phase field method domain and slurry domain. 6. The improved method of a roller scraper in a light-cured ceramic 3D printing pavement according to claim 1, characterized in that the step of setting boundary conditions for the geometric model of the fluid domain is: the part that will be in contact with the air Set as Open Boundary, set Scraper Boundary as Moving Mesh Boundary, and set Roller Boundary as Wall Moving. 7. The improved method of a roller scraper in a light-cured ceramic 3D printing paving material according to claim 1, characterized in that, the geometric model of the fluid domain is divided into grids automatically according to the preset maximum grid size lattice, the solver is a transient solver. 8. The improved method of a roller scraper in a light-cured ceramic 3D printing paving material according to claim 1, wherein step S3 comprises: S31. According to the process parameters, set the physical field, set the boundary conditions, divide the grid, and set the solver for the geometric model of the fluid domain to generate a calculation model; S32. Perform fluid simulation calculation on the calculation model to obtain a simulation result; S33. Judging whether the simulation result is converged; S34. When the simulation result converges, execute step S3. 9. The method for improving the roller scraper in a light-cured ceramic 3D printing material according to claim 8, wherein step S33 comprises: Get preset tolerances as well as actual results; Calculate the relative error with the actual result according to the simulation result; Judging whether the relative error is smaller than the preset allowable error; When the relative error is smaller than the preset allowable error, it is judged that the simulation result converges. 10. An improved device for roller scrapers in photocured ceramic 3D printing materials, characterized in that it includes: acquisition equipment and processing equipment, the acquisition equipment is connected to the processing equipment, and the processing equipment is used to establish rollers The fluid domain geometric model of the scraper in the process of photocuring ceramic 3D printing material; The acquisition device is used to acquire process parameters; The processing equipment is also used to set the physical field, set the boundary conditions, divide the grid and set the solver for the geometric model of the fluid domain according to the process parameters; The processing equipment is also used to change the structural parameters of the roller scrapers in the geometric model of the fluid domain multiple times and calculate them separately to obtain the pressure values before multiple scrapers; The processing device is further configured to determine, according to the plurality of pressure values before the doctor blade, the structural parameter of the roller doctor blade corresponding to the minimum pressure value before the doctor blade.

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