Abstract Four-dimensional (4D) printing is an advanced application of 3D printing with the additional shapes changes over time. For appropriate shape changes, 4D printing has been developed using shape memory materials or multi-material structures with different deformation behaviors in response to an external stimulus. In this study, an efficient 4D printing method was developed using a material extrusion (ME) type 3D printer and a single thermoplastic polymer without a shape memory function. To impose different deformation behaviors in a single thermoplastic material, the printing paths were programmed intentionally, and the resulting anisotropy was used to generate a unique thermal deformation in response to a thermal stimulus. The anisotropic thermal deformations of the longitudinally and transversely printed parts were investigated by analyzing the directional size changes of homogeneously laminated bars. This anisotropy was then used to enable 4D printing by applying heterogeneous lamination in which the transverse and longitudinal printing paths were used consecutively. This heterogeneous lamination showed bending deformation after heat treatment, and the effect of lamination strategy on the order of bending was investigated experimentally. The proposed 4D printing method was further applied to induce localized bending deformation by laminating isotropic and anisotropic regions selectively, which enabled a self-assembly function.

中文翻译：

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使用 3D 打印热塑性部件的各向异性热变形进行 4D 打印

摘要 四维 (4D) 打印是 3D 打印的高级应用，其附加形状随时间而变化。对于适当的形状变化，4D 打印已经开发使用形状记忆材料或具有不同变形行为的多材料结构来响应外部刺激。在这项研究中，使用材料挤出 (ME) 型 3D 打印机和没有形状记忆功能的单一热塑性聚合物开发了一种有效的 4D 打印方法。为了在单一热塑性材料中施加不同的变形行为，故意对打印路径进行编程，并使用由此产生的各向异性来响应热刺激产生独特的热变形。通过分析均匀层压钢筋的方向尺寸变化，研究了纵向和横向打印部件的各向异性热变形。然后，通过应用连续使用横向和纵向打印路径的异质层压，这种各向异性被用于实现 4D 打印。这种异质层压在热处理后表现出弯曲变形，并通过实验研究了层压策略对弯曲顺序的影响。通过选择性地层压各向同性和各向异性区域，进一步应用所提出的 4D 打印方法来诱导局部弯曲变形，从而实现自组装功能。然后，通过应用连续使用横向和纵向打印路径的异质层压，这种各向异性被用于实现 4D 打印。这种异质层压在热处理后表现出弯曲变形，并通过实验研究了层压策略对弯曲顺序的影响。通过选择性地层压各向同性和各向异性区域，进一步应用所提出的 4D 打印方法来诱导局部弯曲变形，从而实现自组装功能。然后，通过应用连续使用横向和纵向打印路径的异质层压，这种各向异性被用于实现 4D 打印。这种异质层压在热处理后表现出弯曲变形，并通过实验研究了层压策略对弯曲顺序的影响。通过选择性地层压各向同性和各向异性区域，进一步应用所提出的 4D 打印方法来诱导局部弯曲变形，从而实现自组装功能。