3D-printed magnetic response artificial muscle, manufacturing method and application of 3D-printed magnetic response artificial muscle

Abstract

The invention discloses a 3D-printed magnetic response artificial muscle and a manufacturing method and application thereof, and belongs to the field of 3D printing materials.The manufacturing method of the 3D-printed magnetic response artificial muscle comprises the following steps that polydimethylsiloxane, a curing agent and Ecoflex-0020 are mixed and stirred, and a material substrate is obtained; mixing and stirring the neodymium iron boron magnetic powder and the fumed silica powder; magnetic slurry is obtained; printing the magnetic slurry to obtain an artificial muscle sample; drying and curing the artificial muscle sample to obtain a cured artificial muscle sample; magnetizing and magnetizing the solidified artificial muscle sample to obtain a magnetic response artificial muscle; the magnetic field driving deformation is applied to the artificial muscle for the first time, so that the artificial muscle has relatively large deformation, can realize relatively high-frequency driving and has relatively large bandwidth; artificial muscles of various sizes can be manufactured through the slurry direct-writing printing technology.

Description

Technical Field

[0001] The present invention belongs to the field of 3D printing materials, and in particular relates to a 3D printed magnetic response artificial muscle, a manufacturing method and an application thereof. Background Art

[0002] Artificial muscle is a general term for a class of materials and equipment that contracts, expands or bends within a component due to external stimuli such as temperature, humidity, current, voltage, light, etc. Artificial muscles are inspired by the single-component nature and low weight of natural muscles, while being able to cover a wider range of specific power. These characteristics overcome the limitations of traditional actuators and provide a powerful, lightweight and portable solution. Compared with traditional mechanical actuators and actuation structures, artificial muscles are smaller, lighter and easier to carry, and are suitable for emerging fields such as soft robots and intelligent equipment. At present, common artificial muscles include liquid crystal elastomers, hydrogels, electroactive polymers, curled artificial muscles, shape memory alloys / polymers, etc.

[0003] With the development of science and technology, the current artificial muscles cannot meet the existing needs due to their defects. For example, temperature-driven artificial muscles are limited by thermal conductivity. Even if they are cooled by water or air, they cannot quickly recover after shrinking in a high-temperature environment. They cannot achieve fast, high-frequency driving, and high-temperature driving is difficult to apply to the human body. Voltage-driven electroactive polymers can achieve rapid contraction and relaxation under the action of high-frequency voltage. The disadvantage is that the driving strain is small and the driving voltage is as high as 4 kilovolts, which is very dangerous and difficult to apply. Humidity-responsive polymer fibers are often used in the field of smart fabrics because of their large strain. They can respond in environments with different humidity, but the shortcomings of slow response speed and difficulty in rapid recovery when the fabric is thick are always difficult to solve. Summary of the invention

[0004] In view of the deficiencies in the prior art, the present invention proposes a 3D-printed magnetic-responsive artificial muscle, a manufacturing method and applications thereof.

[0005] A method for manufacturing a magnetically responsive artificial muscle by 3D printing, comprising the following steps:

[0006] Mixing polydimethylsiloxane, a curing agent and a polyester elastomer, stirring to obtain a material base;

[0007] Mixing and stirring NdFeB magnetic powder and fumed silica powder to obtain magnetic slurry;

[0008] The magnetic slurry is 3D printed to obtain an artificial muscle sample;

[0009] drying and solidifying the artificial muscle sample to obtain a solidified artificial muscle sample;

[0010] The solidified artificial muscle sample is magnetized to obtain a magnetically responsive artificial muscle.

[0011] Preferably, the mass ratio of polydimethylsiloxane:curing agent:polyester elastomer is 2:0.2:3.

[0012] Preferably, the curing temperature is 120°C.

[0013] Preferably, the curing agent comprises a prepolymer having vinyl side chains.

[0014] Preferably, the magnetization intensity is 3T.

[0015] Preferably, the volume fraction of the NdFeB magnetic powder is 35% of the total volume of the NdFeB magnetic powder and the fumed silica powder.

[0016] Preferably, the mass fraction of the fumed silicon dioxide powder is 3% of the material base.

[0017] A 3D-printed magnetically responsive artificial muscle device comprises a mesh contraction structure and small magnetic blocks; the small magnetic blocks are arranged below and on both sides of the mesh contraction structure; the mesh contraction structure is in the shape of a rhombus with an obtuse angle of 150°.

[0018] The application of the above-mentioned magnetic responsive artificial muscle device or the magnetic responsive artificial muscle manufactured by the above-mentioned manufacturing method in manufacturing robots and intelligent equipment.

[0019] The beneficial effects of the present invention include:

[0020] 1. For the first time, magnetic field driven deformation is applied to artificial muscles, which enables them to achieve high frequency drive while having a relatively large deformation amount and a relatively large bandwidth.

[0021] 2. Slurry direct writing printing technology can produce artificial muscles of various sizes to meet different usage scenarios. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, for ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative work.

[0023] Figure 1 An unmagnetized magnetically responsive artificial muscle printed by slurry direct writing;

[0024] Figure 2It is a magnetically responsive artificial muscle after magnetization. Because the soft material matrix is ​​relatively soft, it is in a contracted state under the interaction of the attractive force of the magnetic particles in the matrix.

[0025] Figure 3 Schematic diagram of a magnetically responsive artificial muscle lifting a 20g load within 0.15s under the action of a magnetic field;

[0026] Figure 4 It is a schematic diagram of the magnetization of magnetically driven deformation and the deformation principle after magnetization;

[0027] Figure 5 is a schematic diagram of different driving strains at different frequencies;

[0028] Figure 6 This is one actuation cycle of the hydrogel artificial muscle;

[0029] Figure 7 This is one actuation cycle of the shape memory alloy coil artificial muscle. DETAILED DESCRIPTION

[0030] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0031] Comparative Example 1

[0032] There are two types of hydrogel artificial muscles: the lower critical solution temperature and the upper critical solution temperature. When the temperature is below the lower critical solution temperature, the hydrophilic interaction with water is dominant, and the hydrogel with a combination of hydrophobic and hydrophilic segments in the polymer chain expands, while when the temperature is above the lower critical solution temperature, the hydrogen bonds of water are broken, and the hydrophobic interactions between polymer chains are dominant, resulting in the swelling of the hydrogel. Another type is that when the temperature is below the upper critical solution temperature, strong hydrogen bonds will produce a complex structure, but as the temperature rises to the critical solution temperature, the hydrogen bonds break and the hydrogel begins to expand, such as Figure 6 .

[0033] Compared with magnetic response artificial muscles, hydrogel artificial muscles have a slow response speed and a slow recovery speed. They cannot be driven at high frequencies and their working environment is also relatively limited. The following is an example of the entire response time process of one of the hydrogel artificial muscles.

[0034] Shape memory alloy artificial muscles usually make shape memory alloys into coils to cause large deformations, and provide Joule heat as a stimulus to drive the shape memory alloy coils. During this period, the shape memory effect of the heated shape memory alloy triggers contraction by increasing stiffness and generates corresponding driving force, such as Figure 7 Then, after the shape memory alloy coil begins to cool, it loses force and its stiffness decreases to its initial state, ready for the next heating. Due to the slow cooling, the low bandwidth and slow actuation speeds of SMAs have long been troublesome, limiting possible applications.

[0035] Example 1

[0036] 1. Preparation of magnetic slurry

[0037] Weigh PDMS and its curing agent, and put them into a ball mill with the B component of Ecoflex-0020, with a mass ratio of PDMS: curing agent: Ecoflex = 2:0.2:3, and stir manually for 5 minutes to obtain a soft material substrate. Weigh 35% volume fraction (of the total volume) of NdFeB magnetic powder and 3% fumed silica powder relative to the mass of the soft material substrate, put them into a ball mill, and stir manually for 5 minutes. The mass ratio of magnetic slurry to small balls is 1:1, and mix them in a planetary ball mill at a speed of 600r / min for 20 to 30 minutes.

[0038] 2. Printing artificial muscle samples

[0039] The prepared slurry was loaded into a syringe and printed using a conical needle with an inner diameter of 260 μm. The metal slurry was extruded at a pressure of 1.5 to 1.7 MPa. The printing extrusion parameters were: layer height 0.20 to 0.23 mm, and printing speed 10 to 12 mm / s.

[0040] 3. Artificial Muscle Sample Solidification

[0041] The artificial muscle sample was placed in a drying oven, and the curing temperature was 120°C and the curing time was 2 hours to obtain an unmagnetized artificial muscle sample; Figure 1 .

[0042] 4. Magnetization of Artificial Muscle Samples

[0043] Example 2

[0044] The solidified artificial muscle sample was placed vertically and contracted, and placed in a magnetizer with a magnetization intensity of 3T to obtain a magnetically responsive artificial muscle; Figure 2 .

[0045] The contraction structure adopts a mesh structure, which has better contraction than the fiber structure and can achieve greater strain. Small blocks are added below and on both sides of the rhombus at an obtuse angle of 150° to enhance the deformation and driving ability of the structure, so that the magnetic artificial muscle can achieve faster and more powerful driving. When the artificial muscle is magnetized in the contracted state, the NdFeB magnetic particles in the matrix are oriented in the direction of N at the top and S at the bottom. When the magnet approaches the magnetic response artificial muscle from above, the magnetic field strength is enhanced, and the magnetic particles in the matrix will generate a certain force under the action of the magnetic field. The magnetic small blocks on both sides and below are attracted, and the rhombus structure of the artificial muscle shrinks to a flat shape, lifting the suspended weight.

[0046] The magnetization method adopts the template magnetization method, which is to fix the manufactured sample according to the pre-conceived shape, and then put it into the magnetizer for magnetization. When the sample is in the magnetic field of the same direction again, it will be deformed into the pre-set shape. Compared with path magnetization, the magnetization effect of template magnetization is better for magnetizing magnetic particles during printing, which is 1.5 times the intensity of path magnetization, and can achieve greater deformation and generate greater force. NdFeB is selected because its magnetization effect is better than other magnetic particles, with higher remanence and magnetic coercive force, which can better deform and output greater force, such as Figure 4 .

[0047] Example 3

[0048] Magnetic field driven deformation is to embed magnetic particles into a soft material matrix and mix them, and then produce samples of a certain shape through templates or 3D printing. The magnetic particles in the matrix are oriented by path magnetization or template magnetization. Then, under the action of the driving magnetic field, the sample can change according to the pre-set shape. Compared with traditional driven deformation, magnetic field driven deformation can not only perform relatively large deformation, but also quickly deform and recover, and achieve high-frequency driving; in addition, the magnetic field can also remotely drive the deformed sample, and it is harmless to the human body and can be applied to various aspects of human medical treatment.

[0049] Slurry direct writing printing technology is a versatile and low-cost 3D printing technology. It refers to the process of extruding a paste or "ink" through a small nozzle at ambient temperature to create objects to produce printed parts with suspended and unsupported fibers. Compared with traditional mold forming methods, slurry direct writing printing methods can achieve more complex structures through modeling or path programming. Slurry direct writing printing has been widely used in the manufacture of magnetic field-driven deformation specimens. It can be customized to manufacture specimens of the desired shape, and can also be combined with origami, paper cutting and other technologies to manufacture magnetic field-driven deformation specimens with different deformation modes.

[0050] Example 4

[0051] The magnetic responsive artificial muscle lifts a load of 20g under the action of a magnetic field. The permanent magnet approaches from above. The time used in the lifting process is 0.15s. The response speed is very fast, and the strain is 40.44%. The response effect is as follows Figure 3 .

[0052] Example 5

[0053] The magnetic response artificial muscle is fixed to one end of the bracket through a plastic rod. A permanent magnet is fixed on the upper part of the magnetic response artificial muscle. The crank rocker mechanism is used to achieve the up and down movement of the permanent magnet, thereby controlling the change in the size of the magnetic field. The crank rocker mechanism achieves movement through a small electric shock, and by controlling the speed of the motor, it can achieve different frequency drives, thereby achieving response effects at different frequencies, such as Figure 5 At 0.1Hz-3Hz, due to inertia and self-absorption of small blocks on both sides, the strain of the magnetic response artificial muscle shows an increasing trend. At a higher frequency of 3Hz-8Hz, because the permanent magnet stays at the bottom for a shorter time, the driving magnetic field driving time is also shorter. Although the magnetic response artificial muscle has a fast response speed, it still leads to a decrease in strain.

[0054] In the range of 0.1Hz-3Hz, the strain shows an upward trend, but as the frequency increases (3Hz-8Hz), the strain gradually decreases.

[0055] In the description of this specification, the description with reference to the terms "one embodiment", "example", "specific example", etc. means that the specific features, structures, materials or characteristics described in conjunction with the embodiment or example are included in at least one embodiment or example of the present invention. In this specification, the schematic representation of the above terms does not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials or characteristics described can be combined in any one or more embodiments or examples in a suitable manner.

[0056] The above shows and describes the basic principles, main features and advantages of the present invention. Those skilled in the art should understand that the present invention is not limited to the above embodiments, and the above embodiments and descriptions are only for explaining the principles of the present invention. Without departing from the spirit and scope of the present invention, the present invention may have various changes and improvements, and these changes and improvements all fall within the scope of the present invention to be protected.

Claims

1. A method for manufacturing a magnetically responsive artificial muscle by 3D printing, characterized in that: The following steps are involved: The polydimethylsiloxane, curing agent and polyester elastomer are mixed and stirred to obtain a material base; the NdFeB magnetic powder and fumed silica powder are mixed and stirred to obtain a magnetic slurry; The magnetic slurry is 3D printed to obtain an artificial muscle sample; drying and solidifying the artificial muscle sample to obtain a solidified artificial muscle sample; The solidified artificial muscle sample is magnetized to obtain a magnetically responsive artificial muscle.

2. The method for manufacturing a magnetically responsive artificial muscle by 3D printing according to claim 1, characterized in that: The mass ratio of the polydimethylsiloxane:curing agent:polyester elastomer is 2:0.2:

3.

3. The method for manufacturing a magnetically responsive artificial muscle by 3D printing according to claim 1, characterized in that: The curing temperature is 120°C.

4. The method for manufacturing a magnetically responsive artificial muscle by 3D printing according to claim 1, characterized in that: The curing agent includes a prepolymer having vinyl side chains.

5. The method for manufacturing a magnetically responsive artificial muscle by 3D printing according to claim 1, characterized in that: The magnetization intensity is 3T.

6. The method for manufacturing a magnetically responsive artificial muscle by 3D printing according to claim 1, characterized in that: The volume fraction of the NdFeB magnetic powder is 35% of the total volume of the NdFeB magnetic powder and the fumed silicon dioxide powder.

7. The method for manufacturing a magnetically responsive artificial muscle by 3D printing according to claim 1, characterized in that: The mass fraction of the fumed silicon dioxide powder is 3% of the material base.

8. A 3D printed magnetically responsive artificial muscle device, characterized in that: It comprises a mesh contraction structure and magnetic small pieces; the magnetic small pieces are arranged below and on both sides of the mesh contraction structure; the mesh contraction structure is in the shape of a rhombus with an obtuse angle of 150 degrees.

9. Use of the magnetic responsive artificial muscle device according to claim 8 or the magnetic responsive artificial muscle manufactured by the manufacturing method according to any one of claims 1 to 7 in manufacturing robots and intelligent equipment.

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