Prototyping Techniques Research Articles

A capacitive tactile force sensor with mutual fringe effect and parallel plate design for robot assisted surgery

This paper presents a unique design of a single-axis tactile force sensor by a mutual parallel plate and fringing effect of an electric field that is generated between stationary patterned electrodes in the sensor. The proposed sensor can measure the normal and shear forces with high sensitivity and linear response. The capacitive tactile sensor is fabricated by low-cost rapid prototyping techniques using conductive ink for electrode printing that is printed on a polyethylene terephthalate sheet by an inkjet printer. Ecoflex 00-30 and silicone rubber RTV-528 are used as the dielectric medium and dome for force application. A finite element method analysis is performed for deciding the dimensions of the sensor's stationary electrodes. The force measurement ranges of the sensor for the normal and shear axis are 4 N and 2 N, respectively. The proposed tactile sensor shows a highly linear response, which makes it a suitable match for force feedback in robotic surgery.

Evaluation of model precision and performance discrepancies in simulated vs. experimental testing of vertical axis wind turbines

The increasing global demand for clean and renewable energy has driven significant advancements in wind turbine technology. This paper explores innovative approaches to harnessing wind energy, with a particular focus on the deployment of vertical axis wind turbines (VAWTs) in urban environments and highways. By strategically positioning turbines along roadways, where wind generated by moving vehicles offers a reliable energy source, this study investigates the potential for integrating wind energy generation with existing infrastructure. The study compares the power generation of three VAWT designs—Giromill, Windside, and Helicoidal—through both physical prototypes and computational simulations. Utilizing 3D printing technology, scaled prototypes of each turbine were constructed and tested under controlled conditions in road separators to capture the wind generated by vehicular traffic. Computational Fluid Dynamics (CFD) software was used to simulate turbine performance under similar conditions. The primary objective is to evaluate the accuracy and error margin between physical tests and computational models, aiming to assess the feasibility of using CFD simulations as a predictive tool for real-world turbine performance. The results will contribute to bridging the knowledge gap in wind energy research, particularly in Colombia, by providing new insights into the comparative efficiency of experimental and simulated approaches. This work builds on previous studies related to wind turbine aerodynamics and 3D prototyping techniques, with a focus on urban wind energy harvesting solutions.

A high sensitivity, low cost and fully decoupled multi-axis capacitive tactile force sensor for robotic surgical systems.

This paper presents the design of a multi-axis capacitive tactile force sensor with a fully decoupled output response for input normal and shear forces. A patterned elastomer is used as a dielectric layer between capacitive electrodes of the sensor that allows to achieve relatively higher sensitivity. The sensor is fabricated utilizing a low-cost rapid prototyping technique and is characterized for normal and shear forces in the range of 0 ~ 10 N and 0 ~ 3.1 N respectively. The achieved force sensitivity for the normal axis is 2.03%/N and for shear axes is 1.67%/N. The difference between the estimated force from the sensor and actual force applied is negligible, which demonstrates the accuracy of the sensor. The reliability of the sensor is analysed by performing hysteresis and repeatability tests. The hysteresis error is found to be 4.94% and 4.69% for normal and shear forces respectively. The repeatability error of the sensor is less than 5%, which shows the stability of the sensor. The high sensitivity, linear output response, high force measurement range, reliability and low cost make the proposed tactile sensor suitable for the force feedback in the robotic surgical systems.

Transformative Biomaterials in Burn Care: Utilizing Scaffolds, Hydrogels, and Chitosan for Optimized Healing and Scar Reduction

With over a million patients per year in the USA alone, burns are among the most common injuries in the world. In addition to preventing difficulties during burn injuries, the growing impact of scaffolds, hydrogels, cell scaffolds, and cell sheets with healing boosting elements expedite triggers and strengthens re-epithelialization and wound healing, which limits the creation of scars. While superficial partial-thickness and superficial burns typically heal without surgery, severe burns require special care, including topical antimicrobial surgery or bandages. Usually composed of polymeric biomaterials, scaffolds offer the structural support needed for cell adhesion and the subsequent formation of tissue. The term "tissue engineering triad" often refers to cells, scaffolds, and growth-stimulating signals. This may be accomplished in several ways by combining different polymers. Simple (planar) 3D structures may be produced using conventional and rapid prototyping techniques, but complicated structures have been successfully produced by carefully controlling the Molds and processing parameters. For biomedical and tissue engineering applications, chitosan has been widely employed (skin, bone, cartilage, and vascular grafts to substrates for mammalian cell culture). Additionally, it is renewable, biocompatible, biodegradable, nonantigenic, bioactive, and nontoxic.

Lower Limb Rehabilitation Exoskeleton Robots, A review

Using a lower limb exoskeleton for rehabilitation (LLE) Lower limb exoskeleton rehabilitation robots (LER) are designed to assist patients with daily duties and help them regain their ability to walk. Even though a substantial portion of them is capable of doing both, they have not yet succeeded in conducting agile and intelligent joint movement between humans and machines, which is their ultimate goal. The typical LLE products, rapid prototyping, and cutting-edge techniques are covered in this review. Restoring a patient's athletic prowess to its pr-accident level is the aim of rehabilitation treatment. The core of research on lower limb exoskeleton rehabilitation robots is the understanding of human gait. The performance of common prototypes might be used to match wearable robot shapes to human limbs. To imitate a normal stride, robot-assisted treatment needs to be able to control the movement of the robot at each joint and move the patient's limb.

Classification of melt pool states for defect detection in laser directed energy deposition using FixConvNeXt model

Abstract Laser directed energy deposition (L-DED) has emerged as a promising technique for rapid prototyping due to its cost-effectiveness and efficiency. However, the intricate and multi-scale physics of the process hinder its widespread application. This paper addresses the challenge by focusing on real-time identification of melt pool states to detect defects early and minimize resource wastage. To achieve this, a FixConvNeXt model was developed for fast and accurate monitoring of melt pool states. This model was trained using 5000 melt pool images captured during the printing of single-track deposits from a charge-coupled device. To evaluate its performance, FixConvNeXt was compared with other models using various metrics. Experimental results demonstrated that FixConvNeXt achieved superior performance in accurately identifying melt pool states with 99.1% accuracy, while also reducing computation burden and processing time. The mechanism of classification by FixConvNeXt was explained using gradient-weighted class activation mapping. The research findings highlight the potential application of online process monitoring in L-DED. This study lays the foundation for future development of an efficient deep learning network for automatic defect detection and feedback control.

Comparison of the Torsional Strength of Material Samples Made Using Selected Rapid Prototyping Methods

In recent years, there has been a marked increase in the use of rapid prototyping techniques that support industrial processes. The analysis of studies on strength tests of parts manufactured using additive techniques from model materials and hybrid composites usually includes tests of material and strength parameters based on uniaxial tension, bending, and compression tests. For elements manufactured from polymeric materials using traditional methods (e.g. injection moulding), data obtained from these tests are sufficient to determine the strength of the material and to apply the results in the product design process. In the case of the layered extrusion method, due to the model construction process, strength data based on standard samples do not have a direct transposition on the strength of machine parts operating under various load ranges, especially torsional loads. The publication presents the results of tests on the torsional strength of cylindrical samples with splines produced by layered extrusion, vacuum casting technology, and hybrid technology, which combines both technologies. The test samples were made using a Prusa i3 MK3 3D printer and the plasticised plastic modelling (fused filament fabrication, FFF) method, while PolyJet technology was used to create a reference model. The findings indicate that hybrid technology, in which a thin-walled mould is filled with a chemically hardened polymer, achieves the desired strength for the manufactured parts while maintaining dimensional accuracy and shape. The research results show that producing rotating elements using the hybrid technology reduces the sample core’s ability to undergo plastic deformation due to the adhesion between the materials and the occurrence of notches resulting from the model production process using the layered extrusion method.

DIPHORM: An Innovative DIgital PHOtogrammetRic Monitoring Technique for Detecting Surficial Displacements of Landslides

Monitoring surface displacements of landslides is essential for evaluating their evolution and the effectiveness of mitigation works. Traditional methods like robotic total stations (RTSs) and GNSS provide high-accuracy measurements but are limited to discrete points, potentially missing the broader landslide’s behavior. On the contrary, laser scanner surveys offer accurate 3D representations of slopes and the possibility of inferring their movements, but they are often limited to infrequent, high-cost surveys. Monitoring techniques based on ground-based digital photogrammetry may represent a new, robust, and cost-effective alternative. This study demonstrates the use of multi-temporal images from fixed and calibrated cameras to achieve the 3D reconstruction of landslide displacements. The method presented offers the important benefit of obtaining spatially dense displacement data across the entire camera view and quasi-continuous temporal measurement. This paper outlines the framework for this prototyping technique, along with a description of the necessary hardware and procedural steps. Furthermore, strengths and weaknesses are discussed based on the activities carried out in a landslide case study in northeastern Italy. The results from the photo-monitoring are reported, discussed, and compared with traditional topographical data, validating the reliability of this new approach in monitoring the time evolution of surface displacements across the entire landslide area.

Optimizing the Performance of Nickel Electrocatalysts with Regular Arrays of Linear Ridge-like Features for Enhancing the Oxygen Evolution Reaction

The oxygen evolution reaction (OER) represents a major source of inefficiency in the production of green hydrogen via electrocatalytic water splitting. At high overpotentials relevant to industrial rates of gas production, bubbles can contribute substantially to these inefficiencies by inhibiting the mass transport of electrolyte and partially obstructing the electrochemically active surface area (Aecsa) of an electrode.1 Arrays of microscale features have been shown to improve the efficiency of gas evolving reactions, including the OER. The performance of electrodes modified with linear ridge-like surface features has been previously observed to increase with the spacing between the ridges with a separation of up to 200 µm, but it was not known whether this trend continues indefinitely.2 The present study utilizes rapid prototyping techniques, including microscope projection photolithography and electrodeposition, to determine whether an optimal ridge separation exists between 200 and 450 µm. At a relatively high overpotential of 1.8 V (vs Hg/HgO) in an alkaline electrolyte, the performance of these ridges was observed to increase up to a critical separation, after which the performance decreased to a level comparable to a planar electrode at a wider separation between the ridges. Chronoamperometry measurements indicated that ridges with this optimal spacing attained a current response nearly 3× that of a planar electrode when normalized to (Aecsa). A better understanding of the reasons for this observed trend was pursued using high speed imaging. Direct observations of bubble production on the surfaces of the electrodes provided a deeper understanding of how the distribution of gas bubbles on an electrode affects performance.

Preventing bacterial adhesion on scaffolds for bone tissue engineering

Bone implant infection constitutes a major sanitary concern which is associated to high morbidity and health costs. This manuscript focused on overviewing the main research efforts committed up to date to develop innovative alternatives to conventional treatments, such as those with antibiotics. These strategies mainly rely on chemical modifications of the surface of biomaterials, such as providing it of zwitterionic nature, and tailoring the nanostructure surface of metal implants. These surface modifications have successfully allowed inhibition of bacterial adhesion, which is the first step to implant infection, and preventing long-term biofilm formation compared to pristine materials. These strategies could be easily applied to provide three-dimensional (3D) scaffolds based on bioceramics and metals, of which its manufacture using rapid prototyping techniques was reviewed. This opens the gates for the design and development of advanced 3D scaffolds for bone tissue engineering to prevent bone implant infections.

Sensitive detection of CaMV35S based on exponential rolling circle amplification reaction and CRISPR/Cas12a using a portable 3D-printed visualizer

The biosafety of genetically modified organisms (GMOs) is still a subject of debate among the public, so developing practical and accurate GMOs detection techniques is crucial. However, the existing testing methodologies for GMOs products do not possess the requisite sensitivity and flexibility necessary for effective GMOs surveillance. In this study, our exponential rolling cycle amplification with the CRISPR/Cas12a assay (E-RCA-CRISPR/Cas12a) has successfully enhanced the limit of detection (LOD) for the CaMV35S fragment to 10 aM in a total of 100 min. Rolling cycle amplification can be initiated by the target CaMV35S sequence, utilizing Nb.BbvCI endonuclease nicking activity for the exponential rolling cycle amplification and the trans-cleavage activity of Cas12a for the detection and signal amplification. Our research greatly improves the amplification efficiency through this cyclic process. To reduce the reliance on signal reading devices, we also build a custom 3D-printed visualization vessel and combine a color-reading app on the smartphone to read the fluorescent signals through for sample visualization and analysis. Under ideal circumstances, the limits of detection of our convenient device is 1 fM. We also integrate the exponential rolling circle amplification (E-RCA-CRISPR/Cas12a) assay with the lateral flow strip (LFA) to achieve reading device-free detection with the LOD of 50 fM. Testing the plant and soy sauce samples successfully demonstrated the method’s applicability. The sensing platform thus offers a prototype technique for quick detection of various nucleic acid targets and has optimum sensitivity, specificity, and on-site detection capability.

A New Automatic Process Based on Generative Design for CAD Modeling and Manufacturing of Customized Orthosis

As is widely recognized, advancements in new design and rapid prototyping techniques such as CAD modeling and 3D printing are pioneering individualized medicine, facilitating the implementation of new methodologies for creating customized orthoses. The aim of this paper is to develop a new automatic technique for producing personalized orthoses in a straightforward manner, eliminating the necessity for doctors to collaborate directly with technicians. A novel design method for creating customized wrist orthoses has been implemented, notably featuring a generative algorithm for the parametric modeling of the orthosis. To assess the efficacy of the developed algorithm, a case study was conducted involving the design and rapid prototyping of a wrist orthosis using Fused Deposition Modeling (FDM) technology. Subsequently, the developed algorithm was tested by clinicians and patients. The results obtained indicate that the implemented algorithm is user-friendly and could potentially enable non-expert users to design customized orthoses. These results introduce innovative elements of originality within the CAD modeling, offering promising solutions to the challenges associated with the design and production of customized orthoses. Future developments could consist of a better investigation regarding the parameters that influence the accuracy of the scanning and of the printing processes.

Microfluidic system for generating a three-dimensional (3D) vascularized islet-on-a-chip model

Diabetes is a disease associated with the insufficiency of pancreatic endocrine part, consisting mainly of pancreatic islets. Currently, diabetes is considered the fastest growing civilization disease. Globally, over 440 million people suffer from diabetes, and it is estimated that this number will increase to 700 million by 2045. Pancreatic islets are complex, highly vascularized mini-organs, and only the development of a fully functional vascularized pancreatic islet model could lead to the progress of knowledge about diabetes evolution, new therapeutic strategies, and the islet generation for applications in regenerative medicine. Therefore, the main goal of our study was to develop a microfluidic system for the simultaneous culture of two three-dimensional (3D) research models. The device presented in this article was used to simultaneously culture a model of a blood vessel composed of endothelial cells (HUVEC) developed using the Viscous Finger Patterning (VFP) technique and a model of the pancreatic islet, which was developed using a co-culture of α and β cells. During the research, device production method was optimized, and for this purpose, the most precise micro-milling technique was compared with the rapid prototyping technique - 3D printing. The spatial arrangement of cells in the developed models, their morphology, and viability were visualized using fluorescence staining and confocal microscopy analysis. This article presents preliminary research to develop a long-term culture of a complex model imitating the connection between the microvessel and the pancreatic islet, which in the future will be used to develop new therapeutic strategies or generate fully functional islets.

Aptasensor platform based on electrochemical Paper-Based analytical device for histamine detection

This paper outlines a simple, affordable, and highly flexible rapid prototyping technique for creating electrochemical paper-based analytical devices (ePADs). The craft cutter printer used for ePAD fabrication offers high flexibility and simplicity, eliminating the need for specialized equipment such as a wax printer by generating both electrode patterns and hydrophilic barriers. The ePAD was utilized to construct an aptasensor for the determination of histamine, which is essential for several physiological functions, including gastric secretion, narcolepsy, cell differentiation, cell growth, neurotransmission, and neuromodulation. Following the preparation of an ePAD with a unique design specific to this work, surface characterization was conducted using scanning electron microscopy (SEM), energy-dispersive X-ray spectroscopy (EDX), cyclic voltammetry (CV), and electrochemical impedance spectroscopy (EIS). A single-use aptasensor was created by immobilizing histamine-specific aptamer onto the working electrode surface of the ePAD. By optimizing all experimental parameters, histamine detection was successfully performed using the differential pulse voltammetry (DPV) technique. The reproducibility and selectivity of the aptasensor were examined, and its potential applicability to real samples was tested in an artificial saliva. These findings suggest that the ePAD-based aptasensor provides a cost-effective and reliable method for histamine detection, with potential applications in various bioanalytical contexts.

Biomechanical design optimization and experimental verification of Bezier curve based two-sectional cervical pillow with variable-density cellular structure

The fundamental function of an optimal cervical pillow is to provide sufficient support to maintain normal spinal alignment and minimize biological stress on the contact surface throughout sleep. The recent advancements in cervical pillows have mainly focused on the subjective and objective evaluations of support comfort, as well as the relationship between pillow height and cervical vertebrae posture. However, only a few studies have addressed shape design guidelines and mechanical performances of the pillows themselves. In this study, a two-sectional contour cervical pillow comprising an arc and a Bezier curve is designed to support the head and neck. The design of the arc-shaped neck section incorporates the Cobb’s angle and Borden value from healthy individuals to reflect the consistency of normal cervical anatomical features. The Bezier curve-based head section takes the head length and neck depth into account as significant individual differences. Static analysis and lattice optimization are performed in ANSYS Workbench to develop a variable-density cellular structure, aimed at improving air permeability and reducing the risk of pressure ulcers associated with the cervical pillow. The rapid prototyping technique fused deposition modeling (FDM) and thermoplastic material polylactic acid (PLA) are employed for fabricating different cellular structures. The results demonstrate that the neck section experiences less stress and greater deformation in comparison to the head section, indicating good comfort and support provided by the designed cervical pillow. Additionally, the compressive, bending, and cushion properties of the 3D-printed cervical pillow with variable-density cellular structure are experimentally validated, further confirming its effectiveness.

SIPUKET (SISTEM INFORMASI PELAYANAN UMUM PEMBUATAN SURAT KETERANGAN) BERBASIS WEB PADA KELURAHAN TEGALMUNJUL

People in the Tegalmunjul sub-district are forced to travel home to retrieve personal files or documents that do not meet the requirements for making a certificate because the system is still operated manually. Examples of these documents include incomplete KTP, KK, or other personal documents that are required for making a certificate. People typically have to wait a very long period to receive a certificate. Time is lost waiting for the letter to be written, making this less efficient and effective. For all system requirements to be satisfied, a system or software must be in place that allows individuals to simply pick up the completed letter, initials, and stamp subdistrict. In this study, correspondence software is developed using the prototype technique in the hopes of improving the effectiveness of correspondence activities for the community.

Materials Characterization of Stereolithography 3D Printed Polymer to Develop a Self-Driven Microfluidic Device for Bioanalytical Applications.

Stereolithography (SLA) 3D printing is a rapid prototyping technique and reproducible manufacturing platform, which makes it a useful tool to develop advanced microfluidic devices for bioanalytical applications. However, limited information exists regarding the physical, chemical, and biological properties of the photocured polymers printed with SLA. This study demonstrates the characterization of a commercially available SLA 3D printed polymer to evaluate the potential presence of any time-dependent changes in material properties that may affect its ability to produce functional, capillary-action microfluidic devices. The printed polymer was analyzed with Fourier transform infrared-attenuated total reflectance, contact angle measurements, tensile test, impact test, scanning electron microscopy, and fluid flow analysis. Polymer biocompatibility was assessed with propidium iodide flow cytometry and an MTT assay for cell viability. The material characterization and biocompatibility results were then implemented to design and fabricate a self-driven capillary action microfluidic device for future use as a bioanalytical assay. This study demonstrates temporally stable mechanical properties and biocompatibility of the SLA polymer. However, surface characterization through contact angle measurements shows the polymer's wettability changes over time which indicates there is a limited postprinting period when the polymer can be used for capillary-based fluid flow. Overall, this study demonstrates the feasibility of implementing SLA as a high-throughput manufacturing method for capillary action microfluidic devices.

A New Approach to Carbon Nanotube Filament Nanostructuring for Additive Manufacturing.

A new technique of additive prototyping filament volumetric nanostructuring based on the high-speed mechanical mixing of acrylonitrile-butadiene-styrene (ABS) copolymer granules and single-walled carbon nanotube (CNT) powder (without prior dispersion in solvents) is considered. The morphological spectra of scanning electron microscopy (SEM) images of nanostructured filament slice surfaces were obtained and characterized with the original mathematical simulation. The relations of structural changes in the "ingredient-matrix" polymer system with dielectric and mechanical properties of the ABS-based filaments were established. The supplementation of 1.5 mass.% of CNT powder to the ABS filament composition leads to the tensile strength increasing from 36 ± 2 to 42 ± 2 MPa. It is shown that the greater the average biharmonic amplitude and the morphological spectrum localization radius of the slice surfaces' SEM images, the lower the electrical resistance of the corresponding nanostructured filaments. The possibility of carbon nanotube-modified filament functional layers forming using the extrusion additive prototyping technique (FFF) on the surface of plasma-chemically modified PET substrates (for the creation of load cell elements) is experimentally demonstrated.

The Process of Digital Data Flow in RE/CAD/RP/CAI Systems Concerning Planning Surgical Procedures in the Craniofacial Area

This paper presents the process of digital data flow in RE/CAD/RP/CAI systems to develop models for planning surgical procedures in the craniofacial area. At the first RE modeling stage, digital data processing, segmentation, and the reconstruction of the geometry of the anatomical structures were performed. During the CAD modeling stage, three different concepts were utilized. The first concept was used to create a tool that could mold the geometry of the cranial vault. The second concept was created to prepare a prototype implant that would complement the anterior part of the mandibular geometry. And finally, the third concept was used to design a customized prototype surgical plate that would match the mandibular geometry accurately. Physical models were made using a rapid prototyping technique. A Bambu Lab X1 3D printer was used for this purpose. The process of geometric accuracy evaluation was carried out on manufactured prototypes of surgical plates made of ABS+, CPE, PLA+, and PETG material. In the geometric accuracy evaluation process, the smallest deviation values were obtained for the ABS plus material, within a tolerance of ±0.1 mm, and the largest were obtained for CPE (±0.2 mm) and PLA plus (±0.18 mm). In terms of the surface roughness evaluation, the highest value of the Sa parameter was obtained for the PLA plus material, which was 4.15 µm, and the lowest was obtained for the CPE material, equal to 3.62 µm. The knowledge of the flow of digital data and the identification of factors determining the accuracy of mapping the geometry of anatomical structures allowed for the development of a procedure that improves the modeling and manufacturing of anatomical structures within the craniofacial region.

Tensile, flexural, and mode-I cracking behavior of interpenetrating phase composites (IPC), developed using additively manufactured PLA-based structures with different infill densities and epoxy resin polymer as matrix

Interpenetrating phase composites (IPC) materials are designed to combine the advantages of made-from materials or develop an intended behavior. Recently, the use of 3D printed structures has received attention due to advantages, such as the rapid and cheap prototyping techniques of complex structures. However, most materials, such as polylactic acid (PLA) used for conventional 3D printing, have low strength and insignificant durability. To overcome these issues, the excellent characteristics of polymer adhesives, such as epoxy resin, can be used to increase their strength and durability. In this paper, PLA-based 3D printed samples and epoxy resin adhesive were merged to develop an interpenetrating phase composite. The samples were printed with 25, 50, 75, and 100 infill percentages and tested in direct tensile, bending, and mode-I fracture. From the results, it can be seen that reducing the infill percentage to 75, 50, and 25 % reduces the tensile strength to 16, 9, and 3 MPa (−40 %, −66 %, and −90 % compared to the sample with 100 % infill with 26 MPa strength), adding epoxy resin to develop an IPC, results in 24, 29 and 32 MPa tensile strength. Compared to 3D-printed parts with the same infill percentages, the IPCs have 150, 320, and 1140 % higher tensile strengths, respectively. Also, the failed samples were reviewed by scanning electron microscope.