Directly Printable Flexible Strain Sensors for Bending and Contact Feedback of Soft Actuators

This paper presents a fully printable sensorized bending actuator that can be calibrated to provide reliable bending feedback and simple contact detection. A soft bending actuator following a pleated morphology, as well as a flexible resistive strain sensor, were directly 3D printed using easily accessible FDM printer hardware with a dual-extrusion tool head. The flexible sensor was directly welded to the bending actuator’s body and systematically tested to characterize and evaluate its response under variable input pressure. A signal conditioning circuit was developed to enhance the quality of the sensory feedback, and flexible conductive threads were used for wiring. The sensorized actuator’s response was then calibrated using a vision system to convert the sensory readings to real bending angle values. The empirical relationship was derived using linear regression and validated at untrained input conditions to evaluate its accuracy. Furthermore, the sensorized actuator was tested in a constrained setup that prevents bending, to evaluate the potential of using the same sensor for simple contact detection by comparing the constrained and free-bending responses at the same input pressures. The results of this work demonstrated how a dual-extrusion FDM printing process can be tuned to directly print highly customizable flexible strain sensors that were able to provide reliable bending feedback and basic contact detection. The addition of such sensing capability to bending actuators enhances their functionality and reliability for applications such as controlled soft grasping, flexible wearables, and haptic devices

Geopolymer vs ordinary portland cement: review of the 3-d printing of concrete

Due to the need of the construction industry to implement structures with special and complex designs, mass customization with the lowest cost, especially reducing the labor cost as well as the amount of waste and materials used, the use of concrete 3D printing can be the appropriate solution to these requirements fulfill these options. As a result, a comprehensive and practical study of the major 3D printing methods and their development in the construction industry was carried out in this study. In addition, the use of OPC-based materials and geopolymer-based materials was reviewed and compared due to the development of the materials industry and the advantages and disadvantages of using different types of cementitious materials in the 3D printing of concrete

A Review on the Application of 3D Printing Technology in Pavement Maintenance

To examine the application and significance of 3D printing technology in pavement maintenance engineering, a review of the current developments in principles, types, materials, and equipment for 3D printing was conducted. A comparison and analysis of traditional methods and 3D printing for asphalt pavement maintenance led to an investigation of 3D asphalt printing technologies and equipment. As a result, the following suggestions and conclusions are proposed: 3D printing technology can increase the level of automation and standardization of pavement maintenance engineering, leading to effective improvements in worker safety, climate adaptability, repair accuracy, etc. For on-site repair of cracks and minor potholes, utilizing material extrusion technology a mobile 3D asphalt printing robot with a screw extrusion device can be used for accuracy and flexibility. For efficient repair of varying cracks, material jetting technology with a UAV equipped with a 3D printing air-feeding device can be employed

Process Parameter Optimization of FFF 3D Printed Parts

This work aimed to create a Metal Additive Manufacturing technique, namely Fused Filament Fabrication (FFF), to find the ideal parameters for the printing of 316L stainless steel. The work consisted of adapting and developing the process parameters of FFF to produce tensile specimens. These parameters included the infill pattern, density, printing angle and support structures. In addition, several tests were done, like tensile, surface roughness, and microscopic analysis, to validate the imposed parameters. After gathering the best parameters, a part from the automotive industry was printed to optimise the parameters, and cost analysis was compared with SLM technology. Thus, in this dissertation, the process parameter optimization of the FFF technology was made

Medical Applications of Materials Manufactured by the AM Process

The use of 3D printing for manufacturing parts has made it possible to produce components with complex geometries according to drawings made on the computer. 3D printing offers many advantages in the manufacture of polymers and composites, including high precision, low cost, and custom geometry. Several techniques are used in 3D printing, the ones discussed in this monograph are the main ones for polymers. These are: fused deposition modeling (FDM), Injection 3D printing (3DP), Stereolithography (SLA), and finally selective laser sintering (SLS). The 3D printing technique has several applications, however, the focus in this project is to analyze the various medical applications and the main advantages and disadvantages associated with it. Some of the main applications of this type of technology that will be described throughout the project are: - Bioprinting of tissues and organs - Customized Implants and Protheses - Anatomical Models for Surgical Application - Pharmaceutical Application The main objective will be to analyze, for these procedures, what are the advantages associated with the use of 3D technology and what are the goals for the future in this field. In addition, it will be important to mention the advantages and disadvantages of this combination (3D printing and medicine) in a more general overview, identifying numerous advantages but also potential risks that need to be taken into account. In order to deepen the analysis further, two practical cases will be studied, ensuring their contextualization for the project and also a verification of the improvements and processes facilitated by the application of 3D technology in these fields

Medical Applications of Materials Manufactured by the AM Process

The use of 3D printing for manufacturing parts has made it possible to produce components with complex geometries according to drawings made on the computer. 3D printing offers many advantages in the manufacture of polymers and composites, including high precision, low cost, and custom geometry. Several techniques are used in 3D printing, the ones discussed in this monograph are the main ones for polymers. These are: fused deposition modeling (FDM), Injection 3D printing (3DP), Stereolithography (SLA), and finally selective laser sintering (SLS). The 3D printing technique has several applications, however, the focus in this project is to analyze the various medical applications and the main advantages and disadvantages associated with it. Some of the main applications of this type of technology that will be described throughout the project are: - Bioprinting of tissues and organs - Customized Implants and Protheses - Anatomical Models for Surgical Application - Pharmaceutical Application The main objective will be to analyze, for these procedures, what are the advantages associated with the use of 3D technology and what are the goals for the future in this field. In addition, it will be important to mention the advantages and disadvantages of this combination (3D printing and medicine) in a more general overview, identifying numerous advantages but also potential risks that need to be taken into account. In order to deepen the analysis further, two practical cases will be studied, ensuring their contextualization for the project and also a verification of the improvements and processes facilitated by the application of 3D technology in these fields.IncomingObjectius de Desenvolupament Sostenible::9 - Indústria, Innovació i Infraestructur

3D printed pneumatic soft actuators and sensors: their modeling, performance quantification, control and applications in soft robotic systems

Continued technological progress in robotic systems has led to more applications where robots and humans operate in close proximity and even physical contact in some cases. Soft robots, which are primarily made of highly compliant and deformable materials, provide inherently safe features, unlike conventional robots that are made of stiff and rigid components. These robots are ideal for interacting safely with humans and operating in highly dynamic environments. Soft robotics is a rapidly developing field exploiting biomimetic design principles, novel sensor and actuation concepts, and advanced manufacturing techniques. This work presents novel soft pneumatic actuators and sensors that are directly 3D printed in one manufacturing step without requiring postprocessing and support materials using low-cost and open-source fused deposition modeling (FDM) 3D printers that employ an off-the-shelf commercially available soft thermoplastic poly(urethane) (TPU). The performance of the soft actuators and sensors developed is optimized and predicted using finite element modeling (FEM) analytical models in some cases. A hyperelastic material model is developed for the TPU based on its experimental stress-strain data for use in FEM analysis. The novel soft vacuum bending (SOVA) and linear (LSOVA) actuators reported can be used in diverse robotic applications including locomotion robots, adaptive grippers, parallel manipulators, artificial muscles, modular robots, prosthetic hands, and prosthetic fingers. Also, the novel soft pneumatic sensing chambers (SPSC) developed can be used in diverse interactive human-machine interfaces including wearable gloves for virtual reality applications and controllers for soft adaptive grippers, soft push buttons for science, technology, engineering, and mathematics (STEM) education platforms, haptic feedback devices for rehabilitation, game controllers and throttle controllers for gaming and bending sensors for soft prosthetic hands. These SPSCs are directly 3D printed and embedded in a monolithic soft robotic finger as position and touch sensors for real-time position and force control. One of the aims of soft robotics is to design and fabricate robotic systems with a monolithic topology embedded with its actuators and sensors such that they can safely interact with their immediate physical environment. The results and conclusions of this thesis have significantly contributed to the realization of this aim