Academic literature on the topic 'Pre-assembled 3D printed gears'

We report on the fabrication of a syringe-based platform for automation of a colorimetric malaria-Ab assay. We assembled this platform from inexpensive disposable plastic syringes, plastic tubing, easily-obtainable servomotors, and an Arduino microcontroller chip, which allowed for system automation. The automated system can also be fabricated using stereolithography (SLA) to print elastomeric reservoirs (used instead of syringes), while platform framework, including rack and gears, can be printed with fused deposition modeling (FDM). We report on the optimization of FDM and SLA print parameters, as well as post-production processes. A malaria-Ab colorimetric test was successfully run on the automated platform, with most of the assay reagents dispensed from syringes. Wash solution was dispensed from an SLA-printed elastomeric reservoir to demonstrate the feasibility of both syringe and elastomeric reservoir-based approaches. We tested the platform using a commercially available malaria-Ab colorimetric assay originally designed for spectroscopic plate readers. Unaided visual inspection of the assay solution color change was sufficient for qualitative detection of positive and negative samples. A smart phone application can also be used for quantitative measurement of the assay color change.

Aims This aim of this study was to assess the feasibility of designing and introducing generic 3D-printed instrumentation for routine use in total knee arthroplasty. Materials and Methods Instruments were designed to take advantage of 3D-printing technology, particularly ensuring that all parts were pre-assembled, to theoretically reduce the time and skill required during surgery. Concerning functionality, ranges of resection angle and distance were restricted within a safe zone, while accommodating either mechanical or anatomical alignment goals. To identify the most suitable biocompatible materials, typical instrument shapes and mating parts, such as dovetails and screws, were designed and produced. Results Before and after steam sterilization, dimensional analysis showed that acrylonitrile butadiene styrene could not withstand the temperatures without dimensional changes. Oscillating saw tests with slotted cutting blocks produced debris, fractures, or further dimensional changes in the shape of Nylon-12 and polymethylmethacrylate (MED610), but polyetherimide ULTEM 1010 was least affected. Conclusion The study showed that 3D-printed instrumentation was technically feasible and had some advantages. However, other factors, such as whether all procedural steps can be accomplished with a set of 3D-printed instruments, the logistics of delivery, and the economic aspects, require further study. Cite this article: Bone Joint J 2019;101-B(7 Supple C):115–120

Effective and reliable interconnections are crucial for microfluidics to connect with the macro world. Current microfluidic interfaces are still bulky, expensive, or with issues of clogging and material limitation. In this study, a novel ultraviolet (UV)-assisted coaxial three-dimensional (3D) printing approach was proposed to fabricate hollow microfluidic connectors with advantages of rapid prototyping, fixture-free, and materials compatible. An assembled coaxial nozzle was designed to enable co-flow extrusion, where the inner flow (water) served as the sacrificial layer and the outer flow (adhesive) was cured for shell formation. Furthermore, a converged UV-LED light source was attached to the coaxial nozzle for UV curing of adhesives. UV rheological characterizations were performed to study the UV curing kinematics, and the gelation time was employed to describe the state transition behaviors of UV curable adhesives used in the study. To explore requirements for successful hollow connectors direct printing, processing criteria such as co-flow regime and pre-cure time were investigated. The hollow connectors with an inner channel diameter of ~150 μ m and a height of 5 mm were successfully printed on polymethyl methacrylate (PMMA) and glass substrate. The integration feasibility of the proposed method was also demonstrated by the presented microfluidic device with printed hollow connectors.

This work reports the design, fabrication, and characterization of a centimetre-scale autonomous robot with locomotion based on in-plane piezoelectric resonators and 3D-printed inclined legs. The robot consists of a pair of cooperative piezoelectric motors, an electronic power circuit and a battery-powered microcontroller. The piezoelectric motors feature a lead zirconate titanate (PZT) plate of dimensions 20 mm × 3 mm × 0.2 mm vibrating on its first extensional resonant mode at around 70 kHz. A particular position of 3D-printed inclined legs allowed the conversion of the in-plane movement into an effective forward thrust. To enable arbitrary trajectories of the robot on a surface, two parallel piezoelectric plate motors were arranged in a differential drive scheme. The signals to excite these plates were generated by the microcontroller and adapted by a supplementary electronic circuit to increase the effective voltage supplied by the onboard battery. The fully assembled robot had a size of 27 mm × 15 mm and a weight of 7 grams and reached a linear speed of approximately 15 mm/s and a rotational speed of up to 50 deg./s. Finally, the autonomous robot demonstrated the ability to follow pre-programmed paths.

Heart sounds and heart rate (pulse) are the most common physiological signals used in the diagnosis of cardiovascular diseases. Measuring these signals using a device and analyzing their interrelationships simultaneously can improve the accuracy of existing methods and propose new approaches for the diagnosis of cardiovascular diseases. In this study, we have presented a novel smart stethoscope based on multimodal physiological signal measurement technology for personal cardiovascular health monitoring. The proposed device is designed in the shape of a compact personal computer mouse for easy grasping and attachment to the surface of the chest using only one hand. A digital microphone and photoplehysmogram sensor are installed on the bottom and top surfaces of the device, respectively, to measure heart sound and pulse from the user’s chest and finger simultaneously. In addition, a high-performance Bluetooth Low Energy System-on-Chip ARM microprocessor is used for pre-processing of measured data and communication with the smartphone. The prototype is assembled on a manufactured printed circuit board and 3D-printed shell to conduct an in vivo experiment to test the performance of physiological signal measurement and usability by observing users’ muscle fatigue variation.

The objective of this case report was to describe the clinical sequence for occlusal vertical dimension (OVD) recovering with the manufacture of removable partial dentures (RPD) produced by computer-aided design and rapid prototyping. The patient presented to the Dentistry Department of the Federal University of Rio Grande do Norte reporting dissatisfaction with the superior RPD. At clinical investigation, a fracture in the minor connector and support at the region of tooth 15 was observed, in addition to severe OVD loss. In this case, after obtaining correct OVD, four more sessions were necessary for RPD fabrication. In the first appointment, intraoral scanning was performed to generate STL files used for path of insertion determination in the CAD software. The need for a guide plane on tooth 15 was observed, thus a preparation guide was designed and 3Dprinted to aid axial tooth reduction. At the second visit, after mouth preparation, another intraoral scanning was performed to acquire virtual working models. The RPD framework was designed and 3D printed in a castable resin pattern and invested for cobalt-chromium alloy melting. In the third visit, clinical evaluation of the framework and teeth and artificial gingiva colors selection were performed. The articulated models were then 3D printed, enabling pre-fabricated teeth to be assembled and acrylized. On the fourth appointment, RPD was installed and the patient received routine instructions. In this sense, the use of CAD/CAM technologies presented as a valuable tool to enhance restoration of OVD by the manufacturing of RPD.

Aim: Patient-specific fluid dynamic simulation of pulmonary arteries can be a valuable tool in pre-procedural planning. Materials & methods: For three patients, soft, deformable models of the pulmonary arteries were 3D printed from cardiac magnetic resonance data. In vitro hemodynamics were replicated using a gear flow pump, 40% glycerol solution and a physical Windkessel module. The pulmonary pressures were compared with patient cardiac catheterization pressure. Results: The pulmonary artery pressures and flow volumes had an adequate goodness of fit except for pulmonary pressures in patient 2. Conclusion: Cardiac magnetic resonance angiogram and flow volume data can be leveraged to generate a patient-specific 3D model and reproduce in vivo hemodynamics by means of in vitro simulation.

A robotic arm is one of the most sophisticated components of a humanoid, due to its complexity in multi-degree-of-freedom actuation and sensing, size and weight constraints, and requirement for object manipulation. This paper talks about the design, development, and verification of a low-cost, light-weight robotic manipulator that can achieve anthropomorphic movements. The 5 degree-of-freedom robotic arm has a fully extended length of 31 – inches and weight of 7 - pounds. The joints of the arm were fabricated using mainly 3D printed parts using Polylactic Acid and Nylon and linked with carbon fiber tubing. The arm is actuated by 2 servo motors at the distal joint and 3 brushless DC motors at the proximal joints. All joints of the arm perform at zero backlash through harmonic gear boxes, which are also assembled mainly from 3D printed parts. The robotic arm has demonstrated a comparable performance to similar robotic arms on the market with significantly reduced cost.

Abstract As part of Milwaukee School of Engineering’s (MSOE) 2019 Senior Design program, a design team has worked with Old World Wisconsin (OWW) — a museum in Waukesha County — to incorporate STEM education into their historical platform. This involved introducing methods to teach STEM concepts to visitors, most of which are school children in the K-12 system. Background research on current Science, Technology, Engineering and Mathematics (STEM) methods for K-12 audiences show that there is an overall lack of STEM introduction for students in the United States, and as such, students in the U.S. fail to meet averages for international testing standards for STEM concepts. Research shows that young students require hands on programs in which they can form hypotheses, test hypotheses, and question how these concepts can be applied to real life scenarios. The physical designs in this project consist of stations which relate to OWW’s current exhibits, and introduce statics and dynamics concepts, such as the concepts of mechanical advantage. These concepts are introduced through physical mechanisms that visitors to OWW can interact with in a safe manner, without the need of close supervision. With the guidance of facilitators, school children on field trips will learn mechanics concepts in a tactile and visual manner while being taught key points by the facilitator. The physical designs in this project exist in OWW’s Bicycle Shop, Peterson Wagon Shop, and Loomer Barn. The bicycle shop station consists of a sprocket and chain setup in which visitors can drive a sprocket using a handle, to discover how gear ratios can affect output speeds and torque for a given input speed and torque. The station in the wagon shop has a table with multiple tracks on which a scale wheel can be rolled, to show the relationships between translational and rotational dynamics. In the Loomer Barn, there is a lever station which shows the concepts of moments and moment arms, as well as mechanical advantage, which visitors can solve problems with to understand the relationship between moment arms, and the applied forces required to balance a lever. Also in the barn, a pulley station explores the use of multiple pulleys to make lifting require less force, while increasing the required pulling distances. Each station is accompanied by worksheets that can be distributed to teachers and other visitors via e-mail, which will serve as further supplementary learning tools to enhance visitors’ understanding of the subject material. Design specifications are defined for the size, weight, and types of components to be allowed in the wagon and sprocket modules. These design specifications are met by the finalized designs. The separate stations have undergone some revision over time through different design prototype phases. In the prototype phases, 3D printing was the main means of design, but since these devices are meant to be large and sturdy to offer permanent visual cues to young students, these prototypes were not only temporary solutions, but impossible to 3D print or manufacture within a reasonable cost and time frame. Because of this, the use of externally sourced parts from McMaster-Carr and Menards was decided upon to fulfill the goals of this project. This project was feasible in that it was accomplished by meeting standards related to the background research on STEM education, as well as falling within the realm of historical relevance to OWW’s exhibits. The project was assembled and distributed to OWW within the desired time-frame of both MSOE, and OWW.