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In this study, smart composite materials based on 4D printing technology were used to determine the grasping ability of four-claw gripper of soft robot. First, fused deposition modeling (FDM) is used to prepare polylactic acid (PLA) strips on the surface of a rectangular bamboo substrate to create a single-claw gripper for a smart composite soft robot, while using stimulus (heat) to deform and recover its original shape. Here, the authors first evaluate the deformation and recovery angle of the single-claw gripper of the smart composite soft robot, as well as various processing parameters such as heating temperature and time. This study then used FDM to print PLA ribbons on cross-shaped bamboo sheets to design the four-claw gripper of soft robot and its gripper technology was actuation type. Then, the four-claw gripper of soft robot was used to grab the table tennis ball to test its grasping ability. Finally, four processing parameters (width of claw, pitch of PLA ribbon, heating temperature, and heating time) were applied to determine the grasping ability of the four-claw gripper of soft robot. The optimal processing parameters for the grasping ability of the four-claw gripper of soft robot were width of claw of 20.2 mm, pitch of PLA ribbon of 1 mm, heating temperature of 200[degrees]C, and the heating time of 15 s. The authors also applied the operation window of two processing parameters to discuss the success of the grasping ability of the four-claw gripper of soft robot. The innovation of this study is the use of PLA/bamboo composite materials as the four-claw gripper of soft robot and these materials are cheap, easy to obtain, and can be recycled naturally. This study uses a simple thermal stimulus to enable the four-claw gripper of soft robot to easily grasp irregular objects. Highlights * The innovative composite material of polylactic acid and bamboo fabricated by 3D printing. * Width of claw and heating temperature are the key factors on grasping ability. * Operating window of grasping ability appears on four-claw gripper of soft robot. KEYWORDS 4D printing, grasp behavior, gripper of soft robot, processing parameter, smart composite material, 1 | INTRODUCTION Three-dimensional (3D) printing, also referred to as rapid prototyping (RP) or additive manufacturing (AM), can be applied to robotic, health care, aerospace, sensing and biomedicine fields, and [...]

In this study, polylactic acid (PLA) and thermoplastic polyurethane (TPU) were used to fabricate composite materials with different raster orientations by a 3D printing process. The idea of this study came from the fact that in nature, many plants have vertical or horizontal lines on their leaves or branches. The authors made use of the composite material of a material structure under a thermal effect to achieve the material concept. Finally, their characteristics were observed by applying a thermal effect, tensile tests (to evaluate toughness), and a dynamic mechanical analysis (tan [delta] to evaluate energy absorption). After a thermal effect (temperature) from a heat source was applied, it was found that the material exhibited negative Poisson's ratio (NPR) characteristic. A single material with two layers on 0[degrees] raster orientation of a material in this study had the maximum tan [delta] (energy absorption), an NPR, and toughness regardless of the kind of material. Among the composite materials, 0[degrees] raster orientation of them also had a larger NPR, and the absolute value of Poisson's ratio decreased as the temperature increased. Highlights * The innovative two-layer composite material fabricated by 3D printing. * The material characteristics with various raster orientations are discussed. * PLA0 has the largest tan [delta], toughness, and negative Poisson's ratio. KEYWORDS 3D printing, additive manufacturing, composite material, energy absorption, negative Poisson's ratio, raster orientation, thermal effect, 1 | INTRODUCTION Three-dimensional (3D) printing is a method of additive manufacturing (AM); it is also called rapid prototyping (RP) because it can quickly fabricate good finished products. The stereolithographic [...]

Background: Children with dental caries are treated with stainless steel metal crowns (SSC), but the aesthetics and precision still need to be improved. Currently, both 3D‐printed resin crowns (PRC) and computer‐aided design/computer‐aided manufacture (CAD/CAM) resin crowns (CRC) meet the clinical requirements for crown applications in terms of strength, production time, cost, and aesthetics. Aim: This study replaced SSC with customized resin crowns by 3D printing and CAD/CAM. Design: In this study, PRC, CRC, and SSC were used for incisor and molar restorations, and 60 crowns were made with 10 for each group. The fabrication efficiency, surface characteristics, marginal fit, and stability of the two different crowns were evaluated. Results: PRC and CRC show superior color and surface characteristics, though production times are longer (5.3–12.4 times and 3.3–9.1 times, respectively) than for SSC (p <.05). They, however, can be completed within 80 min. Edge gaps for PRC and CRC are significantly lower (13.0–19.2 times and 13.0–13.7 times) than for SSC (p <.05). All materials exhibit good stability. Conclusion: The 3D‐PRCs and CAD/CAM resin crowns may replace SSCs as a potential choice for clinical child caries. [ABSTRACT FROM AUTHOR]

The current digital dentistry workflow has streamlined dental restoration production, but the effectiveness of digital virtual design and 3D printing for restorations still needs evaluation. This study explores the impact of model-free digital design and 3D-printing placement angles on restorations, including single crowns and long bridges produced with and without casts. The restorations are 3D printed using resin at placement angles of 0°, 60°, and 90°. Each group of samples was replicated ten times, resulting in a total of 120 restorations. The Root Mean Square Error (RMSE) value was used to evaluate the surface integrity of the restoration. In addition, the contact space, edge gap, and occlusal space of restorations produced by different processes were recorded. The results indicate that there was no significant difference in the RMSE value of the crown group (p > 0.05). Changing the bridge restoration angle from 0° to 90° resulted in RMSE values increasing by 2.02 times (without casts) and 2.39 times (with casts). Furthermore, the marginal gaps in the crown group were all less than 60 μm, indicating good adaptation. In contrast, the bridge group showed a significant increase in marginal gaps at higher placement angles (p > 0.05). Based on the findings, virtual fabrication without casts does not compromise the accuracy of dental restorations. When the position of the long bridge exceeds 60 degrees, the error will increase. Therefore, designs without casts and parallel placement result in higher accuracy for dental restorations. [ABSTRACT FROM AUTHOR]

Porous scaffolds fabricated from biodegradable polymers have been widely used and play a vital role in tissue engineering and in situ tissue reconstruction. This study presents a novel fabrication technique involving injection molding and conventional particulate leaching (IM/PL) to obtain the L-shaped nasal scaffold for rhinoplasty. The results indicate that the porous nasal scaffold made by the IM/PL method shows the acceptable biocompatibility and degradation. The nasal scaffold may degrade well after surgery and the cartilage tissue may grow well in it. This IM/PL technique may replace the traditional artificial silicone filler and reduce the surgery cost. POLYM. ENG. SCI., 53:762-769, 2013. © 2012 Society of Plastics Engineers, INTRODUCTION A nose is an important organ of a human body because it is part of a respiratory pathway. Nevertheless, it is necessary to take a rhinoplastic operation when a [...]

This study photo-etches micropatterns on mold inserts and manufactures a light guide plate with microstructures using microinjection molding. The single parameter method is used to investigate flatness and replication with different process parameters for microinjection molding. Mold temperature is the most important factor for plate flatness and microstructure replication of a light guide plate fabricated by microinjection molding. Low mold temperature increases the flatness of light guide plates, whereas a high mold temperature improves height replication of the microstructure of light guide plates. Optimal mold temperature to maintain flatness and increase microstructure replication of light guide plates is 60°C. POLYM. ENG. SCI., 53:212-218, 2013. ©2012 Society of Plastics Engineers, INTRODUCTION A light guide plate is an important component in liquid crystal displays (LCDs) as plates transfer light from a cold cathode fluorescent lamp to the face of a liquid [...]

This work reports a novel and effective procedure for manufacturing the mold insert of microlens arrays. First, the microlens arrays master is formed using room-temperature imprint lithography and photoresist reflow process. Next, electroforming is carried out to fabriccate the metal mold insert from the master. Finally, microinjection molding is used to replicate the molded microlens arrays. The 200 x 200 arrays of molded microlens, with a diameter of 150 µm, a pitch of 200 µm, and a sag height of 11.29 µm for polycarbonate (PC) material and 11.24 µm for polymethylmethacrylate (PMMA) material have been successfully fabricated. The moldability for PMMA material is better than PC material on molded microlens arrays. The average surface roughness of the molded microlen arrays is 4.53 nm for PMMA material and 4.81 nm for PC material. The mold temperature is the most important processing factor for the focal length and sag height of molded microlens arrays. POLYM. ENG. SCI., 51:391-402, 2011. [C]2010 Society of Plastics Engineers, INTRODUCTION In the recent years, microlens arrays have become an important optical component used in many applications such as flat panel display, optical fiber, optical data storage, and optical communication. [...]