3D Printing and Additive Manufacturing最新文献

With the development of science and technology, flexible sensors play an indispensable role in body monitoring. Rapid prototyping of high-performance flexible sensors has become an important method to develop flexible sensors. The purpose of this study was to develop a flexible resin with multi-walled carbon nanotubes (MWCNTs) for the rapid fabrication of flexible sensors using digital light processing additive manufacturing. In this study, MWCNTs were mixed in thermoplastic polyurethane (TPU) photosensitive resin to prepare polymer-matrix composites, and a flexible strain sensor was prepared using self-developed additive equipment. The results showed that the 1.2 wt% MWCNTs/TPU composite flexible sensor had high gauge factor of 9.988 with a linearity up to 45% strain and high mechanical durability (1000 cycles). Furthermore, the sensor could be used for gesture recognition and monitoring and has good performance. This method is expected to provide a new idea for the rapid personalized forming of flexible sensors.

This article investigates a laser-directed energy deposition additive manufacturing (AM) method, based on coaxial powder feeding, for preparing quartz glass. Through synergistic optimization of line deposition and plane deposition experiments, key parameters of laser coaxial powder feeding AM were identified. The corresponding mechanical properties, thermal properties, and microstructure of the bulk parts were analyzed. The maximum mechanical strength of the obtained quartz glass element reached 72.36 ± 5.98 MPa, which is ca. 95% that of quartz glass prepared by traditional methods. The thermal properties of the obtained quartz glass element were also close to those prepared by traditional methods. The present research indicates that one can use laser AM technology that is based on coaxial powder feeding to form quartz glass with high density and good thermodynamic properties. Such quartz glass has substantial potential in, for example, optics and biomedicine.

Three-dimensional (3D) concrete printing technology has been considered promising, attracting extensive attention in the engineering field. Multiwalled carbon nanotubes (MWCNTs) have been used as an additive to reinforce the cement-based material. However, the research on the 3D printed MWCNT-reinforced high-strength concrete is rare. This research is to study the mechanical properties and pore structure of MWCNT-reinforced reactive powder concrete (RPC) for 3D printing. In this research, the workability of the printed RPC mixture with MWCNTs was first tested to pass the criteria of 3D printing. Then, the enhancement effect of MWCNTs on the printed RPC was tested by mechanical properties after hardening. Meanwhile, strength-displacement curves were recorded. In addition, the pore structures of printed RPC were observed and analyzed by X-ray computed tomography (CT) images. The results show that 0.05 wt% MWCNTs have no effect on the workability of the printable RPC slurry. MWCNTs could enhance the mechanical properties of the printed RPC by filling the flaws inside the samples, increasing the viscosity of the RPC slurry and forming bridges between cracks. Besides, 0.05 wt% MWCNTs may cause the failure mode of the printed RPC from brittle failure to ductile failure. In addition, MWCNTs significantly reduced the porosity of the printed RPC by decreasing pores with a volume over 0.01 mm³. As CT images show, the interlayer zone (IZ) of the 3D printed RPC sample is prone to pores, and a higher volume fraction is evident. In particular, within the volume of IZs, the minimum volume fraction at the IZ of 3D printed RPC appears on sample with MWCNTs.