阅读说明：本技术 一种微尺度磁性作动器的4d打印系统与方法 (4D printing system and method of microscale magnetic actuator ) 是由 张宪民 陈耕潮 杨倬波 詹振辉 何振亚 于 2020-11-25 设计创作，主要内容包括：本发明公开一种微尺度磁性作动器的4D打印系统与方法,该4D打印系统包括计算机控制终端、微液滴打印装置和三维操作平台；微液滴打印装置包括微液滴生成模块和磁控模块；三维操作平台设置在微液滴生成模块的正下方；计算机控制终端按照预设打印模型控制磁控模块改变微液滴生成模块中的打印材料的磁极和磁矩,并控制微液滴生成模块打印微液滴在三维操作平台的透明基板上,经过层层打印,最终透明基板上的微液滴经过融合形成磁性作动器。本发明实现打印微尺度磁驱动器的同时编辑各打印纤维的磁化方向,调节灵活,为微尺度驱动器和软体机器人的制造提供了一种简单且高效的方法。(The invention discloses a 4D printing system and a method of a microscale magnetic actuator, wherein the 4D printing system comprises a computer control terminal, a microdroplet printing device and a three-dimensional operating platform; the micro-droplet printing device comprises a micro-droplet generation module and a magnetic control module; the three-dimensional operation platform is arranged right below the micro-droplet generation module; and the computer control terminal controls the magnetic control module to change the magnetic poles and magnetic moments of printing materials in the micro-droplet generation module according to a preset printing model, controls the micro-droplet generation module to print micro-droplets on a transparent substrate of the three-dimensional operation platform, and finally forms the magnetic actuator by fusing the micro-droplets on the transparent substrate through layer-by-layer printing. The invention realizes the printing of the micro-scale magnetic driver and the editing of the magnetization direction of each printing fiber, has flexible adjustment, and provides a simple and efficient method for manufacturing the micro-scale driver and the soft robot.)

1. The utility model provides a 4D printing system of microscale magnetic actuator which characterized in that: the micro-droplet printing device comprises a computer control terminal, a micro-droplet printing device and a three-dimensional operation platform;

the micro-droplet printing device comprises a micro-droplet generation module and a magnetic control module; the three-dimensional operation platform is arranged right below the micro-droplet generation module; and the computer control terminal controls the magnetic control module to change the magnetic poles and magnetic moments of printing materials in the micro-droplet generation module according to a preset printing model, controls the micro-droplet generation module to print micro-droplets on a transparent substrate of the three-dimensional operation platform, and finally forms the magnetic actuator by fusing the micro-droplets on the transparent substrate through layer-by-layer printing.

2. The 4D printing system of claim 1, wherein the micro-droplet generation module comprises an air pump, an injection cartridge, a heating jacket, a feed controller, a replaceable printing needle; the magnetic control module comprises an electromagnetic coil and a magnetic shielding plate;

the air pump is connected with 2 injection charging barrels, the heating sleeve is wrapped outside the injection charging barrels, the tail end of each injection charging barrel is connected with a replaceable printing needle head, the feeding controller is connected with the injection charging barrels, the electromagnetic coils are arranged around the printing needle heads, and the bottoms of the electromagnetic coils are provided with magnetic shielding plates for shielding; the heating sleeve, the feeding controller and the electromagnetic coil are all connected with the computer control terminal.

3. The 4D printing system of claim 1, wherein the three-dimensional operating platform comprises: the device comprises a transparent substrate, an XYZ moving platform, a light shielding cover, an inverted microscope and a shockproof support platform; the transparent substrate, the XYZ moving platform, the inverted microscope and the shockproof support platform are all arranged in the light shielding cover; a blue light LED is arranged on the inverted microscope;

the XYZ moving platform and the inverted microscope are both arranged on the shockproof supporting table, the transparent substrate is arranged on the XYZ moving platform and serves as a printing area, the inverted microscope is located below the transparent substrate, and the XYZ moving platform and the inverted microscope are both connected with the computer control terminal.

4. The 4D printing system of claim 2, wherein the air pump has an air pressure ranging from-800 mbar to 1000mbar, and the air pump is connected to the 2 injection material barrels through three-way transparent hoses, respectively.

5. The 4D printing system of claim 2, wherein 2 injection cartridges are provided on either side of the feed controller, one of the injection cartridges being used to carry magnetic actuator printing material and the other injection cartridge being used to carry printing support material.

6. The 4D printing system of claim 3, wherein the transparent substrate is fixed on the XYZ moving platform by a vacuum chuck, the transparent substrate is a glass substrate, a transparent film material is spin-coated on the glass substrate, the film material is coated with glass powder, and the film material is polyimide or TiO₂、SiO₂SiO and ZrO₂At least one of the above, the powder thickness is 5-15 um.

7. A4D printing method of a microscale magnetic actuator is characterized by comprising the following steps:

s1, preparing a printing material and a supporting material;

and S2, magnetizing the prepared printing material and the support material in a pulse field until the printing material and the support material are saturated, respectively filling the magnetized printing material and the magnetized support material into the cleaned injection charging barrel, installing the printing needle heads with the corresponding models, and setting the working temperature of the charging barrel.

S3, fixing the prepared transparent substrate on an XYZ moving platform, after the working temperature is stable, controlling an air pump, an electromagnetic coil and the XYZ moving platform by a computer control terminal according to a preset printing module, and printing layer by layer on the transparent substrate to obtain a magnetic actuator model;

and S4, carrying out photo-thermal curing on the magnetic actuator model, and stripping and releasing the model after curing.

8. The 4D printing method of claim 7, wherein preparing the printed material comprises:

placing 55-65% of photosensitive resin, 10% of fumed silica particles with the diameter of 20-30nm, 5% of cross-linking agent and catalyst in a high-speed mixer, mixing for 2 minutes at the rotating speed of 1500r.p.m, and uniformly mixing;

adding unmagnetized rubidium, iron and boron particles with volume fraction of 20-30% and diameter of 5 μm into the uniform mixed solution in the high-speed mixer, and mixing at 2000 r.p.m.speed for 3 min in the high-speed mixer; taking out the uniform mixed liquid in the high-speed mixer, putting the uniform mixed liquid into a defoaming machine, defoaming for 1 minute at the speed of 2200r.p.m, and removing redundant bubbles in the uniform mixed liquid to finish the preparation of the printing material;

the preparation of the support material comprises the following steps: the platinum-containing silicone curing catalyst and fumed silica particles having a diameter of 20-30nm were uniformly mixed in a mass ratio of 5: 1.

9. The 4D printing method of claim 7, wherein purging the injection cartridge comprises: placing the injection charging barrel and the printing needle head to be used in an isopropanol environment into an ultrasonic cleaning machine, cleaning for 5 minutes at the power of 800W, and drying by using nitrogen;

preparing the transparent substrate includes: and spin-coating a transparent film material on the cleaned transparent substrate, and spin-coating fine glass powder with the average diameter of 5-10 mu m on the transparent film material.

10. The 4D printing method according to claim 7, wherein the step S4 includes: pre-baking the printed magnetic actuator model on a hot plate at 100 ℃ for 5 minutes in a yellow light chamber, and then curing for 20 minutes at a distance of 10cm under a high-pressure mercury lamp with the ultraviolet power of 125W to finish the curing operation; and (4) placing the magnetic actuator model into a track vibrator to remove the supporting material for stripping and releasing the model.

Technical Field

The invention relates to the technical field of printing, in particular to a 4D printing system and method of a micro-scale driver and a core component of a soft robot, namely a micro-scale response actuator.

Background

In the fields of flexible electronics, soft robots, biomedicine and the like, attention is paid to intelligent soft materials which can respond to stimulation such as external light, heat, electric fields, magnetic fields and the like and deform. Where biomedical applications typically require remote actuation in confined and confined spaces, magnetic fields provide a safe and effective method of operation. The magnetic actuator is one of the core components of the functional robot, and the performance of the magnetic actuator is directly related to the working quality of the functional robot. Meanwhile, with the continuous reduction of research scale, the preparation of microscale magnetic actuators becomes a research difficulty.

The Skylar tips of the university of Massachusetts in 2013 show a 4D printing technology for the first time, the 4D printing technology means that a structure printed by a 3D technology can change in structure or some attributes under the stimulation of an external environment, and the appearance of the 4D printing technology provides a new way and a new method for preparing a micro-scale magnetic actuator. In 2014, Eric dialer and MetinSitti et al applied programmable and dynamically magnetized flexible materials to prepare magnetic micro-gripper robots. 2016, researchers of Guo Zhan Luma and the like propose a programmable magnetic soft material theoretical formula, calculate strategies and prepare the bionic jellyfish robot.

Other varieties of magnetic actuators are constantly being developed. With the progress of magnetic field control, the magnetic response soft material is also developed from embedding discrete magnetic materials to a composite material mixing magnetic particles into various intelligent soft materials, meanwhile, the human beings continuously deepen and understand the micro world, and the size of the magnetic actuator is developed from millimeter level to micron level. However, currently 4D printing techniques that can be programmable at the microscale for the magnetic polarity of the regions of magnetically soft composite materials are still lacking.

Disclosure of Invention

The invention provides a 4D printing system and a method facing a micro-scale driver and a core part of a soft robot, namely a micro-scale magnetic response actuator. Meanwhile, the 4D printing method can be used for efficiently and conveniently preparing the microscale magnetic response actuator, and the prepared microscale magnetic response actuator has the characteristics of easiness in driving, good biocompatibility and the like, and provides a powerful means for expanding the application of the fields of biomedicine and the like.

In order to achieve the purpose, the invention adopts the following technical solutions:

A4D printing system of a microscale magnetic actuator comprises a computer control terminal, a microdroplet printing device and a three-dimensional operating platform; the micro-droplet printing device comprises a micro-droplet generation module and a magnetic control module; the three-dimensional operation platform is arranged right below the micro-droplet generation module; and the computer control terminal controls the magnetic control module to change the magnetic poles and magnetic moments of printing materials in the micro-droplet generation module according to a preset printing model, controls the micro-droplet generation module to print micro-droplets on a transparent substrate of the three-dimensional operation platform, and finally forms the magnetic actuator by fusing the micro-droplets on the transparent substrate through layer-by-layer printing.

Preferably, the micro-droplet generation module comprises an air pump, an injection material cylinder, a heating sleeve, a feeding controller and a replaceable printing needle head; the magnetic control module comprises an electromagnetic coil and a magnetic shielding plate; the air pump is connected with 2 injection charging barrels, the heating sleeve is wrapped outside the injection charging barrels, the tail end of each injection charging barrel is connected with a replaceable printing needle head, the feeding controller is connected with the injection charging barrels, the electromagnetic coils are arranged around the printing needle heads, and the bottoms of the electromagnetic coils are provided with magnetic shielding plates for shielding; the heating sleeve, the feeding controller and the electromagnetic coil are all connected with the computer control terminal.

Preferably, the three-dimensional operation platform comprises: the device comprises a transparent substrate, an XYZ moving platform, a light shielding cover, an inverted microscope and a shockproof support platform; the transparent substrate, the XYZ moving platform, the inverted microscope and the shockproof support platform are all arranged in the light shielding cover; a blue light LED is arranged on the inverted microscope; the XYZ moving platform and the inverted microscope are both arranged on the shockproof supporting table, the transparent substrate is arranged on the XYZ moving platform and serves as a printing area, the inverted microscope is located below the transparent substrate, and the XYZ moving platform and the inverted microscope are both connected with the computer control terminal.

Preferably, the air pressure range of the air pump is-800 mbar to 1000mbar, and the air pump is respectively connected with the 2 injection material cylinders through three-way transparent hoses.

Preferably, 2 injection cartridges are provided on either side of the feed controller, one of the injection cartridges being used to carry the magnetic actuator printing material and the other injection cartridge being used to carry the print support material.

Preferably, the transparent substrate is fixed on an XYZ moving platform through a vacuum chuck, the transparent substrate is a glass substrate, a transparent film material is spin-coated on the glass substrate, glass powder is coated on the film material, and the film material is polyimide or TiO₂、SiO₂SiO and ZrO₂At least one of the above, the powder thickness is 5-15 um.

The invention also provides a 4D printing method of the microscale magnetic actuator, which comprises the following steps:

s1, preparing a printing material and a supporting material;

and S2, magnetizing the prepared printing material and the support material in a pulse field until the printing material and the support material are saturated, respectively filling the magnetized printing material and the magnetized support material into the cleaned injection charging barrel, installing the printing needle heads with the corresponding models, and setting the working temperature of the charging barrel.

S3, fixing the prepared transparent substrate on an XYZ moving platform, after the working temperature is stable, controlling an air pump, an electromagnetic coil and the XYZ moving platform by a computer control terminal according to a preset printing module, and printing layer by layer on the transparent substrate to obtain a magnetic actuator model;

and S4, carrying out photo-thermal curing on the magnetic actuator model, and stripping and releasing the model after curing.

Preferably, preparing the printed material comprises: placing 55-65% of photosensitive resin, 10% of fumed silica particles with the diameter of 20-30nm, 5% of cross-linking agent and catalyst in a high-speed mixer, mixing for 2 minutes at the rotating speed of 1500r.p.m, and uniformly mixing; adding unmagnetized rubidium, iron and boron particles with volume fraction of 20-30% and diameter of 5 μm into the uniform mixed solution in the high-speed mixer, and mixing at 2000 r.p.m.speed for 3 min in the high-speed mixer; taking out the uniform mixed liquid in the high-speed mixer, putting the uniform mixed liquid into a defoaming machine, defoaming for 1 minute at the speed of 2200r.p.m, and removing redundant bubbles in the uniform mixed liquid to finish the preparation of the printing material;

the preparation of the support material comprises the following steps: the platinum-containing silicone curing catalyst and fumed silica particles having a diameter of 20-30nm were uniformly mixed in a mass ratio of 5: 1.

Preferably, purging the injection cartridge comprises: placing the injection charging barrel and the printing needle head to be used in an isopropanol environment into an ultrasonic cleaning machine, cleaning for 5 minutes at the power of 800W, and drying by using nitrogen;

preparing the transparent substrate includes: and spin-coating a transparent film material on the cleaned transparent substrate, and spin-coating fine glass powder with the average diameter of 5-10 mu m on the transparent film material.

Preferably, step S4 includes: pre-baking the printed magnetic actuator model on a hot plate at 100 ℃ for 5 minutes in a yellow light chamber, and then curing for 20 minutes at a distance of 10cm under a high-pressure mercury lamp with the ultraviolet power of 125W to finish the curing operation; and (4) placing the magnetic actuator model into a track vibrator to remove the supporting material for stripping and releasing the model.

Compared with the prior art, the invention has the following beneficial effects:

(1) the invention controls the feeding amount of the printing material and the supporting material through the high-precision air pump, accurately controls the generation position through the XYZ moving platform, and provides guarantee for the high-precision printing of the micro-scale magnetic actuator.

(2) The invention utilizes the magnetization of the permanent magnet or the electromagnet to flexibly control the magnetization direction of each printing fiber of the printing magnetic actuator, thereby ensuring the flexibility of the magnetic polarity of the printing model area and the variability of the function.

(3) The invention provides a new choice for the multi-material compounding of the magnetic actuator by adopting the double charging barrels and the feeding controller. The printing material is formed by mixing photosensitive resin and NdFeB particles, so that the curing time is effectively shortened, and the printing efficiency is improved.

(4) The invention builds a manufacturing platform, and can be expanded to a plurality of composite printing materials using different types of elastomers, hydrogel matrices and magnetic particles. The introduction of shape programmable soft materials in the design and manufacture offers new possibilities for applications in flexible electronics, biomedical devices and other fields. Meanwhile, the method is consistent with the existing commercial printing process and has strong expansibility.

Drawings

FIG. 1 is a schematic diagram of a 4D printing system for a microscale magnetic actuator of the present invention;

FIG. 2 is a schematic view of the magnetic field distribution near the printing tip of the present invention;

fig. 3 is a schematic diagram of a process for generating micro-droplets in the 4D printing process of the micro-scale magnetic actuator according to the present invention.

Detailed Description

The following description of the embodiments of the present invention is provided with reference to the accompanying drawings. In the following description, for purposes of simplicity and clarity, well-known functions or constructions are not described in detail to avoid obscuring the advantages and features of the invention.

Example 1

As shown in fig. 1, the present embodiment provides a 4D printing system of a micro-scale magnetic actuator, which includes three modules: computer control terminal 1, little liquid drop printing device and three-dimensional operation platform. The computer control terminal 1 mainly drives a control block micro-droplet printing device and a three-dimensional operation platform. The micro-droplet printing device is used for controlling the generation of printing materials, the working temperature and the magnetic polarity of the materials. The three-dimensional operation platform controls the printing position and structure.

Specifically, the micro-droplet printing device comprises a high-precision air pump 2, an injection charging barrel 3, a heating jacket 5, a feeding controller 4, a printing needle 6, an electromagnetic coil 7 and a magnetic shielding plate 8. The high-precision air pump 2 is respectively connected with the 2 injection material cylinders 3 through a three-way transparent hose, the temperature of the injection material cylinders 3 is controlled in real time by the heating sleeve 5 wrapped outside the injection material cylinders 3, the injection material cylinders 3 are connected with the feeding controller 4, the feeding of the corresponding injection material cylinders 3 is controlled by the feeding controller 4, and the tail parts of the injection material cylinders 3 are connected with the replaceable printing needle heads 6.

As shown in figure 2, the electromagnetic coil 7 is positioned around the printing needle 6, the magnetic field pattern and magnetization intensity of the electromagnetic coil 7 are changed during printing to change the magnetic field polarity and magnetization intensity of the printing material in the printing needle 6, the magnetic field induction lines are distributed as shown in figure 2, and the magnetic shielding plate 8 is arranged at the bottom of the electromagnetic coil 7 to shield the magnetic field from influencing the printed material.

The three-dimensional operating platform mainly comprises a transparent substrate 10, an XYZ moving platform 11, an inverted microscope 12 with a blue LED illumination light source, a shockproof support table 13 and a light shielding cover 14, wherein the transparent substrate 10 is fixed through a vacuum chuck on the XYZ moving platform 11. The XYZ moving platform 11 is fixed on an operation platform of an inverted microscope 12 containing a blue light LED illumination light source, the operation platform is integrally arranged on a shockproof support platform 13, the influence of environmental vibration on an operation environment is reduced, and the whole operation space is covered by a light shielding cover 14.

The air pressure range of the high-precision air pump 2 is-800 mbar-1000 mbar. The high-precision air pump 2 is respectively connected with the 2 injection charging barrels 3 through a three-way transparent hose, and the sealing performance of the connection part is improved by adopting an airtight gasket. The double injection barrels 3 are arranged on the side of the feeding controller 4, one of the double injection barrels is used for loading the magnetic actuator printing material, and the other double injection barrel is used for loading the printing support material. The heating sleeve 5 is respectively wrapped outside, the heat range is room temperature to 80 ℃, the feeding of the injection charging barrel 3 and the heating temperature of each charging barrel are controlled by the computer control terminal 1, and the injection charging barrel can be detached. Printing syringe needle 6 adopts airtight packing ring and injection feed cylinder 3 to be connected, and printing syringe needle diameter is adjustable, and the scope is followed 10um ~ 500um, and printing syringe needle 6 can be dismantled. The XYZ three-dimensional moving platform 11 has submicron-level positioning accuracy, is fixed at the shockproof support platform 13, and accurately controls the printing position through the computer control terminal 1. The inverted microscope 12 with the blue light LED illuminating light source has the wavelength of 460nm, the inverted microscope 12 is integrally placed on the shockproof platform 13, and the integral printing area is covered by the light shielding cover to isolate the influence of an external light source on materials. 9 is a hanging droplet.

The transparent substrate 10 is fixed by a vacuum chuck of an XYZ moving platform 11, the transparent substrate 10 is a glass substrate, a transparent film material is spin-coated on the glass substrate, and the film material is polyimide and TiO₂、SiO₂、SiO、ZrO₂And coating glass powder on the film, wherein the average size of the powder is 5-15 um, and the friction influence between a printed sample and a substrate is reduced.

The generation process of micro-droplets in the 4D printing process of the micro-scale magnetic actuator is shown in fig. 3, after checking each working parameter, the high-precision air pump 2 is controlled to feed, that is, an inverted suspended semi-finished micro-droplet 15 is generated at the pinhole of the printing needle 6, the XYZ moving platform 11 is controlled to move upwards until the transparent substrate 10 contacts with the inverted suspended semi-finished micro-droplet 15, and thus a stable bridge structure is formed between the transparent substrate 10 and the printing needle 6. The XYZ moving platform 11 is controlled to move downwards to make the transparent substrate move downwards rapidly, and after the bridge structure is broken, a formed micro-droplet 16 is formed on the transparent substrate. Similarly, the pressure of the high-precision air pump 2 is precisely controlled, the contact time of the transparent substrate 10 and the printing needle tip 6 controls the size of the generated printing liquid drop, and the printing fiber can be formed by plane-moving the XYZ moving platform 11 after the transparent substrate 10 and the printing needle tip 6 are contacted.

The micro-droplet printing device prints micro-droplets according to a preset program, prints the micro-droplets for multiple times, and fuses the micro-droplets to obtain the micro-scale magnetic actuator.

The embodiment also provides a 4D printing method of the micro-scale magnetic actuator of the 4D printing system suitable for the micro-scale magnetic actuator, which includes the following steps:

firstly, 55-65% of photosensitive resin, 10% of fumed silica particles with the diameter of 20-30nm and 5% of cross-linking agent and catalyst are mixed in a high-speed mixer for 2 minutes at the rotating speed of 1500 r.p.m., and the mixture is uniformly mixed.

Adding 20-30% volume fraction of 5 μm diameter unmagnetized rubidium iron boron (NdFeB) particles into the above uniform mixture, and mixing in high speed mixer at 2000r.p.m for 3 min. And then taking out the mixture and placing the mixture into a defoaming machine for defoaming for 1 minute according to the speed of 2200r.p.m, and removing redundant bubbles in the mixed solution to finish the preparation of the printing material. Similarly, a platinum-containing silicone curing catalyst and fumed silica particles having a diameter of 20-30nm were mixed in a mass ratio of 5:1 to complete the support material.

The defoamed printing material is subsequently magnetized to saturation in a pulse magnetizer, the magnetization being 3T. And (3) placing the injection material cylinder and the printing needle head to be used in an isopropanol environment into an ultrasonic cleaning machine, cleaning for 5 minutes at the power of 800W, and drying by using nitrogen. Respectively loading the magnetized printing material and the support material into corresponding injection material barrels after cleaning and blow-drying, installing printing needle heads with the diameter of 50 mu m, and placing and fixing the material barrels and the needle heads at two ends of a feeding controller. The working temperature of the heating sleeve of the charging barrel is set to 30 ℃ and is stabilized for 10 minutes.

And after the working temperature is stable, fixing the prepared transparent substrate by a vacuum chuck on an XYZ moving platform. After the working temperature of the charging barrel is stable, the computer module controls the high-precision air pump, the electromagnetic coil and the XYZ moving platform to print layer by layer on the transparent substrate according to the computer printing model. Wherein preparing the transparent substrate comprises: and spin-coating a transparent film material on the cleaned transparent substrate, and spin-coating fine glass powder with the average diameter of 5-10 mu m on the transparent film material.

In the layer-by-layer printing process, the computer control terminal can alternately control the double injection material cylinders 3 according to a preset printing model, and alternately uses printing materials and supporting materials for printing.

The printed magnetic actuator model was pre-baked on a hot plate at 100 ℃ for 5 minutes in a yellow room, and then cured under a high-pressure mercury lamp with an ultraviolet power of 125W for 20 minutes at a distance of 10cm to complete the curing operation. And placing the model into an orbital shaker to remove the support material for model stripping and release.

The above-mentioned embodiments are preferred embodiments of the present invention, and the present invention is not limited thereto, and any other modifications or equivalent substitutions that do not depart from the technical spirit of the present invention are included in the scope of the present invention.