The Chinese Academy of Sciences (CAS) first proposed a liquid metal suspension 3D printing method. And research and development of equipment
Recently, Chinese Technical Institute of physics and medical cryobiology laboratory first proposed "liquid metal suspension 3D print" concept and method at room temperature rapid manufacturing three-dimensional flexible metal with complex shape and structure of deformable body, and used to assemble three-dimensional stretchable electronic devices. The relevant research results were published on the Advanced Materials Technologies as the cover article.
In the 3D Printing of Liquid entitled Suspension Metal into Self-healing Hydrogel in the study group, will the nature between solid and liquid and self recovery properties of the hydrogel are introduced as transparent support medium, create and confirm the forming method of liquid metal 3D printing suspension (Figure 1), to overcome the surface tension of liquid metal ink, high viscosity low flow, gravity brings technical challenges. In the whole manufacturing process, hydrogel can convert between liquefaction yield and rapid solidification of metal droplets, the viscous force is extremely high, with the relative movement between the print head and the gel, liquid metal extrusion nozzle will immediately drop by necking behavior and nozzle separation, and then support package, viscous gel and fixed.
Figure 1. the cover story of the Journal of advanced materials and technology and the principle and forming process of the suspended 3D printing
Through the stacking of metal microspheres along the planning path, we can finally form the expected three-dimensional structure (Figure 2), and print accuracy can be regulated by needle size, printing speed and gel environment. Both the gel and the liquid metal are flexible materials, and the resulting stereoscopic electronic devices can be stretched and deformed. This research breaks through the traditional rigid structure forming mode and 3D printing category, and has important value in the form of flexible electronic devices, intelligent system rapid manufacturing, and deformable 4D printing.
Figure 2. the twelve zodiac head and stereoscopic circuit of Old Summer Palace based on the principle of liquid metal suspension 3D printing
The research team published in Materials & Design, Printing for Functional Electronics entitled 3D by Injection and Package of Liquid Metals into Channels of Mechanical Structures study, researchers established a mixed processing method for manufacturing three-dimensional flexible electronic structure: first using 3D printing process to fabricate flexible matrix containing hollow micro channel, then to flow in the filling of liquid metal, thus building a flexible electronic device (Figure 3). A series of experiments have revealed the influence of key technological parameters on the forming quality of the device. This work realizes the direct printing and encapsulation of functional electronic devices, which is helpful to the popularization and application of flexible electrons.
Figure 3. principle and application of flexible electronic devices with 3D printing and liquid metal filling
The team previously published in Rapid Prototyping on Journal 3D Printing of Low entitled Direct Melting Point Alloy via Adhesion Mechanism in the paper, through the introduction of metal droplet adhesion forming mechanism, display method using desktop 3D printer direct manufacturing of low melting point metal components at room temperature (Figure 4). Through the comparison with the mechanical and electrical properties of the cast parts, the advantages of the low melting point metal 3D printing parts in the mechanical and electrical behavior are revealed. In the future, the technology can be extended to metal and nonmetal composite printing technology based on multiple sprinklers to realize integrated forming and encapsulation of 3D stereoscopic circuits.
Figure 4. principle of direct 3D printing with low melting point metal adhesion, forming structure and its electrical properties
The platform construction and testing of the above work are supported by the technical support and support of Beijing dream Ink Technology Co., Ltd. Recently, the two sides based on the accumulation of cooperation, developed the world's first commercial mixed liquid metal 3D printing device (Figure 5), the metal / metal hybrid integration of three-dimensional modeling, to increase timber manufacturing technology from manufacturing to manufacturing function has taken a big step, the corresponding equipment has wide application value in the field of 3D electronic devices, intelligent machines, RF communication, scientific research and teaching.
Figure 5. global first liquid metal multi material mixed 3D printer equipment
The above series of novel 3D printing method and original hardware equipment development work, once again demonstrates the advanced liquid metal materials in the rapid manufacturing of flexible functional electronic devices with unique advantages and universal value, is to increase timber manufacturing technology and development of new concept of important leather. The research was supported by the CAS frontier science and Education Bureau and the Beijing Municipal Science and Technology Commission project.