阅读说明：本技术 基于sla快速成型构件的力学性能调控的制造方法 (Manufacturing method for regulating and controlling mechanical property of rapid forming component based on SLA ) 是由 刘浩锐 杨娜娜 赵磊 杨来东 贺立群 刘馨 于 2021-01-11 设计创作，主要内容包括：本发明提供一种于SLA快速成型构件的力学性能调控的制造方法,采用快速成型打印系统进行制造,所述快速成型打印系统包括3D打印设备、激光扫描系统、刮平装置、方位比较系统、基板驱动系统、控制系统以及远程传输模块；该方法包括打印前处理、3D打印模型、激光扫描固化、基板方位调整、激光扫描系统调整以及完成模型打印。该方法利用SLA快速成型技术制备构件,综合对打印过程中的拉伸强度、压缩强度、冲击强度等力学性能进行考虑,从而制备得到各项力学性能优异的快速成型构件。(The invention provides a manufacturing method for regulating and controlling mechanical properties of an SLA (service level agreement) rapid prototyping component, which is manufactured by adopting a rapid prototyping printing system, wherein the rapid prototyping printing system comprises 3D (three-dimensional) printing equipment, a laser scanning system, a strickling device, an orientation comparison system, a substrate driving system, a control system and a remote transmission module; the method comprises the steps of pre-printing, 3D model printing, laser scanning and curing, substrate orientation adjustment, laser scanning system adjustment and model printing completion. The method utilizes an SLA rapid prototyping technology to prepare the component, and comprehensively considers the mechanical properties such as tensile strength, compressive strength, impact strength and the like in the printing process, so that the rapid prototyping component with excellent mechanical properties is prepared.)

1. A manufacturing method for regulating and controlling mechanical properties of an SLA rapid prototyping component is characterized in that: manufacturing by adopting a rapid prototyping printing system, wherein the rapid prototyping printing system comprises 3D printing equipment, a laser scanning system, a strickle device, an orientation comparison system, a substrate driving system, a control system and a remote transmission module;

the method comprises the following specific steps:

a. pretreatment before printing: firstly, inputting a three-dimensional workpiece model to be printed in a control system, and then carrying out layering processing on the three-dimensional workpiece model to obtain information of each cross section layer of the workpiece; meanwhile, establishing an XYZ space rectangular coordinate system in the workpiece printing process by taking the workpiece printing platform as an XY surface, and presetting a printing optimal position (namely the position of each cross section layer and the XYZ space rectangular coordinate system) according to the mechanical property type required by the workpiece;

b. 3D printing the model: the control system transmits information of each section layer of the workpiece to the 3D printing equipment through the remote transmission module, and the 3D printing equipment prints each section layer from bottom to top, so that a resin layer with a certain thickness is formed on the substrate;

c. laser scanning and curing: after the 3D printing equipment prints one layer of cross-section layer, scanning and solidifying the printed cross-section layer by adopting a laser scanning system, and simultaneously sending the cross-section layer and the azimuth information of the substrate to an azimuth comparison system through a remote transmission module in the scanning process;

d. adjusting the orientation of the substrate: the azimuth comparison system compares the cross section layer and the substrate azimuth information acquired by the laser scanning system with an XYZ space rectangular coordinate system according to a preset optimal printing azimuth, and then controls the substrate to rotate through the substrate driving system to adjust the azimuth of the next cross section layer to be printed to the preset optimal azimuth;

e. laser scanning system adjustment: the substrate driving system is used for controlling the substrate to rotate and adjusting the position and the strategy of the laser scanning system at the same time, so that the parameters of each section layer scanned by the laser scanning system are the same;

f. and (3) completing model printing: and e, repeatedly circulating the steps b to e until the model printing is finished.

2. The manufacturing method for regulating and controlling the mechanical property of the SLA rapid prototyping component as set forth in claim 1, is characterized in that: the step a of presetting the optimal printing position according to the mechanical property type required by the workpiece specifically comprises the following steps: if a workpiece with the best tensile strength is obtained, the workpiece is kept in an XY plane inner side in an XYZ space rectangular coordinate system and is printed with each layer of cross section at an angle of 45 degrees with an X axis or a Y axis; if a workpiece with the best impact strength is to be obtained, the workpiece is kept in an XY plane inner side placement state in an XYZ space rectangular coordinate system to print each layer of cross section layer; in order to obtain a workpiece having the best compressive strength, cross-sectional layers are printed on each layer while maintaining the entire axis of the workpiece model at 0 ° to the Y axis in the YZ plane in the XYZ spatial rectangular coordinate system.

3. The manufacturing method for regulating and controlling the mechanical property of the SLA rapid prototyping component as set forth in claim 1, is characterized in that: in the step b, the cross-section layer adopts photosensitive resin as a printing material, and the photosensitive resin comprises: epoxy resin, bifunctional acrylate monomer, trimethylolpropane triglycidyl ether, epoxy acrylate, polyether polyol, free radical photoinitiator, cationic photoinitiator and pigment.

4. The manufacturing method for regulating and controlling the mechanical property of the SLA rapid prototyping component as set forth in claim 1 or 3, characterized in that: the percentage contents of the epoxy resin, the bifunctional acrylate monomer, the trimethylolpropane triglycidyl ether, the epoxy acrylate, the polyether polyol, the free radical photoinitiator, the cationic photoinitiator and the pigment are respectively 38-42%, 18-22%, 12-14%, 9-11%, 9.5-10.5%, 1.8-2.2%, 3.9-4.1% and 0.8-1.2%.

5. The manufacturing method for regulating and controlling the mechanical property of the SLA rapid prototyping component as set forth in claim 1, is characterized in that: the parameters of laser scanning solidification in the step c are as follows: the laser wavelength can be 355nm, and the critical exposure (Ec) is 10mJ/cm²Transmission depth (Dp) 110 μm, laser power 200mW, scanning speed 5000 mm/s.

6. The manufacturing method for regulating and controlling the mechanical property of the SLA rapid prototyping component as set forth in claim 1, is characterized in that: the laser scanning system may employ an ultraviolet laser scanning system.

Technical Field

The invention relates to the technical field of photocuring rapid prototyping, in particular to a manufacturing method for regulating and controlling mechanical properties of an SLA rapid prototyping component.

Background

In recent years, additive manufacturing technology (i.e., 3D printing technology) has been rapidly developed on a global scale as an emerging rapid prototyping technology. The technology has the technical characteristics of rapid free forming without a die, full digitalization, high flexibility and the like, and can manufacture nearly infinite complex geometric structures. With the development of materials and equipment of the additive manufacturing technology, the technology has been widely applied in various fields, such as consumer electronics, automobiles, aerospace, biomedical, military industry, geographic information, artistic design and the like.

The photocuring rapid prototyping (SLA) technology is the earliest developed additive manufacturing technology, and is one of the most deeply researched, most mature and widely applied additive manufacturing technologies at present. SLA has been widely used in the industrial fields of automobiles, electronics, medical treatment, aviation and the like because of its high automation degree in the molding process, good surface quality of the manufactured prototype, high dimensional accuracy and the like; especially in the biomedical field, due to its printing precision and printing range on the micrometer scale and excellent mechanical properties, it has begun to be applied to organ model manufacturing and surgical analysis planning, personalized tissue engineering scaffold materials and prosthetic implant manufacturing. With the progress of SLA technology and the development of materials, the SLA technology is shifted from initial product prototype verification, sample fabrication to final functional product manufacturing, so SLA molded parts must ensure production repeatability, dimensional stability and performance stability. In addition to the performance characteristics of the material, the processing means and parameter changes in the SLA manufacturing process have important influences on the performance, especially the mechanical properties, of the material; the defects of holes, impurities, cracks and the like can be caused in the forming process due to different processing means and parameters, and meanwhile, the printing time can be influenced, so that the printing efficiency is reduced; and the mechanical property of the rapid prototyping component can generate anisotropy, and the function of the printing model in final practical application is influenced.

Disclosure of Invention

Aiming at the problems in the prior art, the invention aims to provide a manufacturing method for regulating and controlling the mechanical properties of an SLA (sheet metal structure) based quick forming component.

The purpose of the invention is realized by the following technical scheme:

a manufacturing method for regulating and controlling mechanical properties of an SLA rapid prototyping component is characterized in that: manufacturing by adopting a rapid prototyping printing system, wherein the rapid prototyping printing system comprises 3D printing equipment, a laser scanning system, a strickle device, an orientation comparison system, a substrate driving system, a control system and a remote transmission module;

the method comprises the following specific steps:

a. pretreatment before printing: firstly, inputting a three-dimensional workpiece model to be printed in a control system, and then carrying out layering processing on the three-dimensional workpiece model to obtain information of each cross section layer of the workpiece; meanwhile, establishing an XYZ space rectangular coordinate system in the workpiece printing process by taking the workpiece printing platform as an XY surface, and presetting a printing optimal position (namely the position of each cross section layer and the XYZ space rectangular coordinate system) according to the mechanical property type required by the workpiece;

b. 3D printing the model: the control system transmits information of each section layer of the workpiece to the 3D printing equipment through the remote transmission module, and the 3D printing equipment prints each section layer from bottom to top, so that a resin layer with a certain thickness is formed on the substrate;

c. laser scanning and curing: after the 3D printing equipment prints one layer of cross-section layer, scanning and solidifying the printed cross-section layer by adopting a laser scanning system, and simultaneously sending the cross-section layer and the azimuth information of the substrate to an azimuth comparison system through a remote transmission module in the scanning process;

d. adjusting the orientation of the substrate: the azimuth comparison system compares the cross section layer and the substrate azimuth information acquired by the laser scanning system with an XYZ space rectangular coordinate system according to a preset optimal printing azimuth, and then controls the substrate to rotate through the substrate driving system to adjust the azimuth of the next cross section layer to be printed to the preset optimal azimuth;

e. laser scanning system adjustment: the substrate driving system is used for controlling the substrate to rotate and adjusting the position and the strategy of the laser scanning system at the same time, so that the parameters of each section layer scanned by the laser scanning system are the same;

f. and (3) completing model printing: and e, repeatedly circulating the steps b to e until the model printing is finished.

And c, further optimizing, wherein the initial position of the substrate in the step a is coplanar with the printing platform, and the substrate is provided with a device for supporting and fixing the printing model.

And c, further optimizing, wherein the step a of presetting the optimal printing position according to the mechanical property type required by the workpiece specifically comprises the following steps: if a workpiece with the best tensile strength is obtained, the workpiece is kept in an XY plane inner side in an XYZ space rectangular coordinate system and is printed with each layer of cross section at an angle of 45 degrees with an X axis or a Y axis; if a workpiece with the best impact strength is to be obtained, the workpiece is kept in an XY plane inner side placement state in an XYZ space rectangular coordinate system to print each layer of cross section layer; in order to obtain a workpiece having the best compressive strength, cross-sectional layers are printed on each layer while maintaining the entire axis of the workpiece model at 0 ° to the Y axis in the YZ plane in the XYZ spatial rectangular coordinate system.

For further optimization, in the step b, the cross-section layer adopts photosensitive resin as a printing material, and the photosensitive resin comprises: epoxy resin, bifunctional acrylate monomer, trimethylolpropane triglycidyl ether, epoxy acrylate, polyether polyol, free radical photoinitiator, cationic photoinitiator and pigment.

The weight percentage of the epoxy resin, the bifunctional acrylate monomer, the trimethylolpropane triglycidyl ether, the epoxy acrylate, the polyether polyol, the free radical photoinitiator, the cationic photoinitiator and the pigment are respectively 38-42%, 18-22%, 12-14%, 9-11%, 9.5-10.5%, 1.8-2.2%, 3.9-4.1% and 0.8-1.2%.

For further optimization, the thickness of each cross section layer printed in the step b is 50-100 μm.

And further optimizing, after the step of 3D model printing, before the step of laser scanning and curing, a strickling device is adopted to strickle the liquid level of the interface layer after printing, so that the problems of bubbles generated on the section layer and uneven thickness are avoided.

For further optimization, the parameters of laser scanning curing in the step c are as follows: the laser wavelength was 355nm, and the critical exposure (Ec) was 10mJ/cm²Transmission depth (Dp) 110 μm, laser power 200mW, scanning speed 5000 mm/s.

For further optimization, the laser scanning system adopts an ultraviolet laser scanning system.

And (f) further optimizing, after the mould is printed in the step f, cleaning the mould with ethanol, then taking down the workpiece, carrying out secondary curing, and polishing away the supporting traces on the surface of the workpiece.

The invention has the following technical effects:

according to the invention, the printing direction and the printing process are adjusted in real time in the printing process, so that the mechanical property of the printed workpiece is controlled, and the excellent mechanical properties of high tensile strength, high compressive strength and high impact strength of the workpiece are ensured, so that the prepared workpiece can adapt to different fields according to different requirements, and the defects of holes, impurities, cracks and the like of the printed workpiece in the photocuring rapid forming process are effectively avoided. The method has the advantages of high forming speed, low cost, excellent mechanical property and the like, and can be widely applied to the field of rapid forming.

Drawings

FIG. 1 is a schematic diagram of the best anisotropic orientation of tensile strength performance during printing according to an embodiment of the present invention.

FIG. 2 is a schematic diagram of an optimal anisotropic aspect of impact strength performance during printing according to an embodiment of the present invention.

FIG. 3 is a schematic diagram of an anisotropic process for optimizing compressive strength performance during printing according to an embodiment of the present invention.

Fig. 4 is a schematic structural diagram of a flat-laid printing workpiece (i.e., a conventional printing method) according to an embodiment of the present invention.

Fig. 5 is a schematic structural diagram of a side-mounted printing workpiece (i.e., the printing method of the present invention) in an embodiment of the present invention.

FIG. 6 is a cross-sectional profile of a side-mounted printed workpiece (i.e., a printing method of the present invention) in an embodiment of the present invention; wherein, fig. 6a is a side-release printing workpiece fracture side surface; FIG. 6b is a side view of the crack source and mirror area of the printed workpiece; FIG. 6c is a transition area of the fogging area and the roughening area of the side-positioned printed workpiece; FIG. 6d is a room temperature crack propagation region of a side-mounted printed workpiece; fig. 6e shows the roughened area with the crack propagation termination of the printed workpiece laid on the side.

FIG. 7 is a cross-sectional profile of a flat-laid print workpiece (i.e., a conventional printing process) in an embodiment of the present invention; wherein, fig. 7a shows the fracture side of the flat printed workpiece; FIG. 7b shows a crack source and mirror area of a flat-laid printed workpiece; FIG. 7c is a transition area between the mist area and the rough area of the flat-laid printing workpiece; FIG. 7d is a room temperature crack propagation region of a flat-laid print workpiece; fig. 7e is a rough area of the crack propagation termination of a flat printed workpiece.

Detailed Description

The technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the drawings in the embodiments of the present invention, and it is obvious that the described embodiments are only a part of the embodiments of the present invention, and not all of the embodiments. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present invention.

Example (b):

a manufacturing method for regulating and controlling mechanical properties of an SLA-based rapid prototyping component is characterized in that: manufacturing by adopting a rapid prototyping printing system, wherein the rapid prototyping printing system comprises 3D printing equipment, a laser scanning system, a strickle device, an orientation comparison system, a substrate driving system, a control system and a remote transmission module;

the method comprises the following specific steps:

a. pretreatment before printing: firstly, inputting a three-dimensional workpiece model to be printed in a control system, and then carrying out layering processing on the three-dimensional workpiece model to obtain information of each cross section layer of the workpiece; meanwhile, establishing an XYZ space rectangular coordinate system in the workpiece printing process by taking the workpiece printing platform as an XY surface, and presetting a printing optimal position (namely the position of each cross section layer and the XYZ space rectangular coordinate system) according to the mechanical property type required by the workpiece;

the initial position of the substrate is coplanar with the printing platform, and a device for supporting and fixing the printing model is arranged on the substrate;

the method for presetting the optimal printing direction of the mechanical property type required by the workpiece comprises the following steps: if a workpiece with the best tensile strength is to be obtained, the workpiece is kept in an XY plane inner side in an XYZ space rectangular coordinate system and is printed in each cross section layer at 45 degrees with an X axis or a Y axis (as shown in FIG. 1); if a workpiece with the best impact strength is to be obtained, printing of each layer of cross section is carried out by keeping the workpiece in a state of being placed on the inner side of an XY plane in an XYZ space rectangular coordinate system (as shown in FIG. 2); in order to obtain a workpiece having the best compressive strength, the workpiece model entire axis is printed for each layer of cross-sectional layer while being held at 0 ° to the Y axis in the YZ plane in the XYZ spatial rectangular coordinate system (as shown in fig. 3).

It should be noted that: the side-on-side state in the XY plane is a state in which the side surface is coplanar with the XY plane, and the side surface is a surface having a relatively small area of the workpiece model (see the comparison in fig. 4 and 5).

b. 3D printing the model: the control system transmits information of each section layer of the workpiece to the 3D printing equipment through the remote transmission module, and the 3D printing equipment prints each section layer from bottom to top, so that a resin layer with a certain thickness is formed on the substrate;

the cross-sectional layer uses a photosensitive resin as a printing material, the photosensitive resin including: 38-42%, preferably 40%, of an epoxy resin, 18-22%, preferably 20%, of a difunctional acrylate monomer, 12-14%, preferably 13%, of trimethylolpropane triglycidyl ether, 9-11%, preferably 10%, of an epoxy acrylate, 9.5-10.5%, preferably 10%, of a polyether polyol, 1.8-2.2%, preferably 2%, of a free radical photoinitiator, 3.9-4.1%, preferably 4%, of a cationic photoinitiator and 0.8-1.2%, preferably 1%, of a pigment;

the thickness of each cross-sectional layer is 50 μm to 100 μm, preferably 60 μm, 75 μm, 80 μm.

After each layer of cross-section layer is printed, the interface layer liquid level after printing is strickled by adopting a strickle device, so that the problems of bubbles generated on the cross-section layer and uneven thickness are avoided.

c. Laser scanning and curing: after the 3D printing equipment prints a layer of cross section layer and is strickled by the strickle device, an ultraviolet laser scanning system is adopted to scan and solidify the printed cross section layer, and the azimuth information of the cross section layer and the substrate is sent to an azimuth comparison system through a remote transmission module during the scanning process;

the parameters of the ultraviolet laser scanning system for scanning and curing are as follows: the laser wavelength was 355nm, and the critical exposure (Ec) was 10mJ/cm²Transmission depth (Dp) 110 μm, laser power 200mW, scanning speed 5000 mm/s.

d. Adjusting the orientation of the substrate: the azimuth comparison system compares the cross section layer and the substrate azimuth information acquired by the laser scanning system with an XYZ space rectangular coordinate system according to a preset optimal printing azimuth, and then controls the substrate to rotate through the substrate driving system to adjust the azimuth of the next cross section layer to be printed to the preset optimal azimuth;

e. laser scanning system adjustment: the substrate driving system is used for controlling the substrate to rotate and adjusting the position and the strategy of the laser scanning system at the same time, so that the parameters of each section layer scanned by the laser scanning system are the same;

f. and (3) completing model printing: repeating the step b to the step e until the model printing is finished; and cleaning the model with ethanol after printing, then taking down the workpiece, carrying out secondary laser scanning solidification (directly scanning the whole workpiece model), and polishing away the supporting traces on the surface of the workpiece.

Test verification:

after the preparation is finished, sequentially carrying out a tensile test, an impact test, a compression test, an SEM analysis and an optical microscopic analysis on the printed workpiece (namely the workpiece printed layer by layer according to a flat state) which is normally placed and is printed by a conventional printing means and the printed workpiece in the embodiment of the invention;

wherein:

the tensile test is carried out according to GB/T1040.1-2006, a proper tensile rate (the tensile rate is 5mm/min in the embodiment) is selected, and the shape and the size of the tensile sample refer to a 1A type sample in the GB/T1040.2-2006 standard;

the impact test is carried out according to GB/T1043-2008, the pendulum energy is 2J, a proper V-shaped notch sample is selected, and the notch size of the sample is according to GB/T1043.1/1eA^b；

The compression test is carried out according to GB/T1448-2005, and the correct compression rate (the compression rate is 2mm/min in the embodiment) and the proper size of the compressed sample are selected;

SEM analysis: cutting the fractured sample into a proper size, placing the sample on a copper table for gold spraying treatment and observing;

optical microscopic analysis: the surface of the sample near the fracture was wiped clean with alcohol and placed on a microscope stage for observation.

SEM analysis was performed with the workpiece of tensile strength laid and laid flat along the XY plane side, as shown in FIGS. 6 and 7 (FIGS. 6a and 7a are optical photographs; FIGS. 6b to 6e and FIGS. 7b to 7e are SEM photographs). As can be seen from fig. 6b and 7b, the crack of the side-lying workpiece (i.e., the printed workpiece of the present invention) originates from a crack inside the workpiece, and the crack of the flat-lying workpiece (i.e., the printed workpiece of the prior art) originates from a defect at a corner of the workpiece; as can be seen from fig. 6c and 7c, defects such as holes are found in the transition area of the cross section of the flat-laid workpiece (i.e., the prior art printed workpiece); it can be seen from fig. 6d and 7d, and fig. 6e and 7e that the crack surface of the flat-laid workpiece (i.e., the printed workpiece in the prior art) is changed stepwise during the crack propagation process, while the fracture surface of the side-laid workpiece (i.e., the printed workpiece in the present invention) is not changed significantly, and the cross section of the side-laid workpiece (i.e., the printed workpiece in the present invention) before fracture is rougher.

The roughness of the fracture surface can indirectly reflect the rate of crack propagation (the smaller the roughness of the fracture surface, the higher the crack propagation speed), so that a flat workpiece (i.e., a prior art printed workpiece) has a relatively high crack propagation speed. As can be seen from fig. 6a and 7a, the side-lying workpiece (i.e., the printed workpiece of the present invention) is broken into a positive fracture, and the crack of the flat-lying workpiece (i.e., the printed workpiece of the prior art) is split when the crack propagates, which indicates that the flat-lying workpiece (i.e., the printed workpiece of the prior art) is more likely to generate non-uniformity or defects such as holes, inclusions, cracks, and the like during the printing process; therefore, it can be inferred that for a brittle photosensitive resin workpiece, the processing orientation affects the crack propagation process to further cause different mechanical properties, the area of the layer interface of the flat-placed workpiece (i.e. the printing workpiece in the prior art) is large and the number of the layer interface is small, the cracks are sparse and long, and the area of the layer section of the side-placed workpiece (i.e. the printing workpiece in the invention) is small and the number of the layer interface is large, so that the interface has a barrier effect on the crack propagation, and further excellent mechanical properties are ensured.

Although embodiments of the present invention have been shown and described, it will be appreciated by those skilled in the art that changes, modifications, substitutions and alterations can be made in these embodiments without departing from the principles and spirit of the invention, the scope of which is defined in the appended claims and their equivalents.