Selective laser sintering (SLS) is a desirable method for fabricating human motion detecting sensors as it can produce a complex shape with different materials that are machinable to specific applications. The bottleneck in the SLS processing of sensors is the preparation of a material that is both flexible and conductive. In this study, carbon nanotubes (CNTs) were selected as a conductive nanofiller and dispersed into a flexible thermoplastic polyurethane (TPU) polymer matrix to prepare TPU/CNT composites for SLS processing pressure sensors. CNTs were first oxidized to prevent them from aggregating in the TPU matrix. TPU/CNT composites were prepared via solution blending and ball milling methods, and the dispersion of the CNTs in the composites was observed by scanning electron microscopy. The thermal properties of TPU/CNT composites with different CNT content were measured, and processing parameters used in the SLS were determined based on differential scanning calorimetry measurements. SLS-processed TPU/CNT composites were prepared with different conductivity and piezoresistive properties. Percolation theory and piezoresistive performance results proved that a 0.25 wt% CNT-containing TPU/CNT composite showed the best pressure sensing ability, and it was successfully used as a sensor to detect plantar pressure distribution in a human foot.

Conductive polymer composites (CPCs) combining with specific microstructures (micropores, microcracks, etc.) can exhibit unique resistance response changes, which can be widely regarded as an effective way to improve sensing performance. This study takes advantage of the characteristics of the formation of tiny pores between crystal grains during selective laser sintering (SLS) processing to introduce a microporous structure into the thermoplastic polyurethane (TPU)/carbon nanotube (CNT) sensing element to prepare a three-dimensional porous conductive structure. The effect of the SLS process on sensing sensitivity, accuracy, and density was studied, and its sensing and forming mechanism were discussed. By adjusting SLS process parameters to control the performance of porous structure sensor elements, a final TPU/CNT sensor element with a wide pressure detection range, high sensitivity, a fast response time, and good stability and durability was developed. Finally, the optimal performance of the developed flexible pressure sensor was successfully used to detect the pressure distribution of the human foot. This study provided a simple and effective research method to develop high-performance flexible pressure sensors.

Aiming at the issues of complex manufacturing processes and unstable bonding after individual manufacturing in current soft manipulator forming methods, this study investigated the mechanical characteristics of a pneumatically driven soft-picking manipulator formed by the stereolithography (SLA) process and evaluated its application in grasping fruits and vegetables. The soft-picking manipulator mainly consists of three soft actuators designed in an integrated folded structure to simplify the manufacturing process compared to a conventional one. A finite element model (FEM) of the actuator was created to analyze the bending deformation capability under different pressures, and the simulated results match well with the experimental ones. Under the 60 kPa pressure, the maximum grasping force for fingertip- and envelope-grasping is 3.94 N and 8.87 N, respectively. The grasping tests of several fruits and vegetables of different weights and sizes by the soft manipulator were examined, and the results showed that the manipulator has strong adaptability. For spherical and elongated fruits and vegetables, the completion time for grasping is approximately 8.59 ± 1.26 s and 10.99 ± 1.79 s, respectively, and for irregularly shaped ones, the pressure is increased accordingly to the increased grasping stability. This study may provide a basis for the development of a soft manipulator for sorting and picking fruits and vegetables.

In response to the urgent demand for sustainable materials and manufacturing, this study explores a high-value pathway for converting forestry waste into functional products. This study systematically optimized the binder jetting 3D printing process for wood–plastic composite materials using poplar powder, a renewable and abundantly available forestry waste, as the raw material. Compared with traditional methods, this additive manufacturing approach minimizes material waste and energy consumption, significantly enhancing both material and energy utilization efficiency, thereby providing technical support for green manufacturing. Using the response surface methodology, the optimal combination of process parameters was determined as follows: adhesive saturation of 62.4%, layer thickness of 62.7 μm, printing speed of 58.6 mm/s, and curing time of 49.9 min. Under these conditions, the cured specimen achieved a density of 0.64 g/cm³, a flexural strength of 0.80 MPa, and a tensile strength of 0.69 MPa, demonstrating excellent mechanical performance. The established robust predictive model further validates the feasibility of wood–plastic composites that offer both superior performance and environmental benefits. This study presents a breakthrough solution for the high-value utilization of wood waste, strongly promoting the advancement of sustainable material science and the circular economy.