On 20 December, 2018, Professor Yanlin Song from Institute of Chemistry, Chinese Academy of Sciences and Professor Nicholas Xuanlai Fang from Massachusetts Institute of Technology collaborated to propose a universal high-speed, high-precision 3D printing strategy. The paper has been published in Research as the cover paper with the title of "Bioinspired Ultra-Low Adhesive Energy Interface for Continuous 3D Printing".(Research. 2018 Article ID: 4795604 DOI: 10.1155/2018/4795604) https://spj.sciencemag.org/research/2018/4795604/.
3D printing is a rapid prototyping technology that constructs three-dimensional structures by means of additive manufacturing, which can significantly improve production efficiency and reduce waste of materials. However, the current 3D printing technology, which uses layer-by-layer or point-by-point printing, is greatly limited in printing speed and accuracy. Although the continuous liquid interface production (CLIP) 3D printing technology reported in 2015 can achieve continuous and high-speed printing, the basic principle limits its wide applications. It is based on the inhibition of free radical polymerization by oxygen which contributes to a continuous liquid film for continuous printing, thus the universality of the printing materials is limited, i.e., it is only suitable for the resin system based on free radical polymerization. At the same time, the introduction of oxygen will cause defects and reduce printing accuracy.
Recently, the research team of Prof. Yanlin Song from Institute of Chemistry, Chinese Academy of Sciences and Prof. Nicholas Xuanlai Fang from Massachusetts Institute of Technology have cooperated to design and prepare surfaces with ultra-low adhesive property by mimicking the ultra-lubricating property of the pitcher plant. The method overcomes the adhesion problem between the printing sample and the curing interface which occurs in traditional 3D printing process. The printing sample can be continuously and rapidly formed with high-precision and high-speed, thereby achieving continuous 3D printing. Meanwhile, the method overcomes the limitation of resin materials and has wide universality. This strategy of controlling the formation of three-dimensional structures through two-dimensional surface properties provides new ideas for the development of 3D printing.
The schematic diagram of the 3D printing system is shown in Fig. 1. The key of the 3D printing strategy is the ultra-low adhesive surface, which is critical to achieve high-speed, high-precision and universality. By using a lubricated surface prepared by mimicking the property of pitcher plant as the curing interface (Figure 1(a)-(c)), the liquid lubricating layer fixed by the surface greatly reduces the interfacial adhesion during curing induced separation. In addition, the liquid resin refilling speed after separation is significantly improved, thus enabling continuous and high-speed 3D printing. The printing time is only related to the printing height (Figure 1(d)).
Figure 1 (a) Scheme of the low adhesive property of the peristome surface of pitcher plant; (b-c) Scheme of reducing adhesion through lubricant; (d) Optical images of printed samples, the printing time is only related to printing height.
By using a 3D printing system that employs an ultra-low adhesive surface as the curing interface, it is easy to continuously and quickly print a block structure and a suspended structure, as shown in Figure 2. The surface is universal for printing materials based on different photopolymerization mechanism, and can be used as the curing interface of current commercial 3D printers to improve the printing accuracy and service life. Therefore, it is anticipated to develop into a promising and universal commercial 3D printing technology.
Figure 2 (a-c) Optical images of bulk structures including (a) the bulk ear structure with contact area of ~ 7 cm × 3 cm; (b) the gate of Heavenly structure; (c) the Roman Colosseum structure. (d) Optical image of the 3D structure composed of freestanding hollow tubes. (e) Optical image of the bird's nest structure with freestanding inner top edge. (f) Optical image of the 3D structure composed of connecting lines.
Tag: Emerging materials research