Ho Chengyeh, Bao Jiali, Xu Jing
State Key Laboratory of Tribology, Department of Mechanical Engineering, Beijing Key Laboratory of Precision/Ultra-Precision Manufacturing Equipment Control, Tsinghua University, Beijing, China.
3D Print Addit Manuf. 2024 Oct 22;11(5):1799-1809. doi: 10.1089/3dp.2023.0126. eCollection 2024 Oct.
The use of deformable materials in 3D printing has allowed for the fabrication of intricate soft robotics prototypes. Polyjet technology, with its ability to print multiple materials in a single print, has been popular in creating such designs. Vero and Agilus, the commercial materials provided by Polyjet, possess shape memory properties, making Polyjet ideal for high-precision and transformable applications. Voxel printing, where users assign materials to voxels, has allowed for the further expansion of design possibilities by tuning the properties of the jetted material. This study aims to investigate how different compositions of uniformly distributed Vero and Agilus voxels affect the thermomechanical properties of the voxel-printed part. In addition, high stiffness Vero droplets surrounded by a soft matrix of Agilus resemble polymer composites, thus calling for the examination of percolation, which is an important phenomenon in polymer composites. The study explores the presence of percolation in voxel-printed mixtures of Vero and Agilus and its impact on mechanical properties. Using dynamic thermomechanical analysis and thermomechanical analysis, the study characterizes the glass transition temperature ( ), maximum allowable strain, and modulus of the voxel-printed material at different compositions. The study found a highly linear relationship between and maximum yield strain with composition, and maximum yield strain occurs at 7°C above . On the other hand, there is a nonlinear relationship between the modulus and composition, which suggested that the percolation phenomenon might have altered the load distribution, therefore causing this inconsistency. So, in this study we used light microscopy, Monte Carlo simulations, and provided mathematical proofs to reveal the percolation threshold in voxel-printed parts, where Vero droplets suddenly form a single network that spreads across the material, altering the load distribution. This study is the first to highlight the percolation phenomenon in Polyjet voxel-printed parts and provides a useful guide for researchers in selecting suitable materials for their specific applications.
在3D打印中使用可变形材料能够制造出复杂的软机器人原型。Polyjet技术能够在一次打印中打印多种材料，因此在创建此类设计时很受欢迎。Polyjet提供的商用材料Vero和Agilus具有形状记忆特性，这使得Polyjet非常适合高精度和可变形应用。体素打印允许用户将材料分配给体素，通过调整喷射材料的属性进一步扩展了设计可能性。本研究旨在探究均匀分布的Vero和Agilus体素的不同组成如何影响体素打印部件的热机械性能。此外，被柔软的Agilus基体包围的高刚度Vero液滴类似于聚合物复合材料，因此需要研究渗流现象，这是聚合物复合材料中的一个重要现象。该研究探索了Vero和Agilus体素打印混合物中渗流的存在及其对机械性能的影响。通过动态热机械分析和热机械分析，该研究表征了不同组成下体素打印材料的玻璃化转变温度（ ）、最大允许应变和模量。研究发现 与最大屈服应变之间与组成存在高度线性关系，且最大屈服应变发生在比 高7°C时。另一方面，模量与组成之间存在非线性关系，这表明渗流现象可能改变了载荷分布，从而导致这种不一致。因此，在本研究中，我们使用光学显微镜、蒙特卡罗模拟并提供数学证明来揭示体素打印部件中的渗流阈值，此时Vero液滴突然形成一个贯穿材料的单一网络，改变了载荷分布。本研究首次突出了Polyjet体素打印部件中的渗流现象，并为研究人员选择适合其特定应用的材料提供了有用的指导。
