scholarly journals Photoelastic Stress Response of Complex 3D-Printed Particle Shapes

2021 ◽  
Author(s):  
Negin Amini ◽  
Joshua Tuohey ◽  
John Long ◽  
Jun Zhang ◽  
David Morton ◽  
...  
Keyword(s):  
3D Printing ◽  
Particle Production ◽  
3 Dimensional ◽  
Complex Particle ◽  
Significant Difference ◽  
Photoelastic Analysis ◽  
3D Printed ◽  
X Ray Computed ◽  
Photoelastic Stress ◽  
Available Technology

Stress visualization within 3-dimensional particles undergoing dynamic processes can greatly advance our understanding of complex particle behaviors. Traditional photoelastic stress visualization methods suffer inherent limitations from lack of available technology for complex particle production. Recently, 3D-printing has created new possibilities for enhancing the scope of stress analysis within physically representative granules. Here, we investigate opportunities offered by 3D-printing a granular material with photoelastic properties. We report the results of X-ray computed tomography and 3D-printing, combined with traditional photoelastic analysis, to visualize strain exhibited within simple discs to reproduced coffee beans. We find that the choice of print layer orientation with respect to the force load affects the optical properties of the discs, without a significant difference in their mechanical properties. Furthermore, we present a first, semi-quantified, measurement of stresses within 3D-printed particles of complex shape. The promising data shows potential for applying this method to complex assemblies of 3-dimensional particles.

scholarly journals Influence of the Postcuring Process on Dimensional Accuracy and Seating of 3D-Printed Polymeric Fixed Prostheses

2020 ◽  
Vol 2020 ◽  
pp. 1-7
Author(s):  
Jaewon Kim ◽  
Du-Hyeong Lee
Keyword(s):  
3D Printing ◽  
Dimensional Accuracy ◽  
3 Dimensional ◽  
Fixed Dental Prosthesis ◽  
Dental Prostheses ◽  
Significant Difference ◽  
Implant Abutments ◽  
Prosthetic Implant ◽  
3D Printed ◽  
Internal Gap

The postcuring process is essential for 3-dimensional (3D) printing of photopolymer-based dental prostheses. However, the deformation of prostheses resulting from the postcuring process has not been fully investigated. The purpose of this study was to evaluate the effects of different postcuring methods on the fit and dimensional accuracy of 3D-printed full-arch polymeric fixed prostheses. A study stone model with four prosthetic implant abutments was prepared. A full-arch fixed dental prosthesis was designed, and the design was transferred to dental computer-aided manufacturing (CAM) software in which supports were designed to the surface of the prosthesis design for 3D printing. Using a biocompatible photopolymer and a stereolithography apparatus 3D printer, polymeric prostheses were produced ( N = 21 ). In postcuring, the printed prostheses were polymerized in three different ways: the prosthesis alone, the prosthesis with supports, or the prosthesis on a stone model. Geometric accuracy of 3D-printed prostheses, marginal gap, internal gap, and intermolar distance was evaluated using microscopy and digital techniques. Kruskal-Wallis and Mann-Whitney U tests with Bonferroni correction were used for the comparison of results among groups ( α = 0.05 ). In general, the mean marginal and internal gaps of cured prostheses were the smallest when the printed prostheses were cured with seating on the stone model ( P < 0.05 ). With regard to the adaptation accuracy, the presence of supports during the postcuring process did not make a significant difference. Error in the intermolar distance was significantly smaller in the model seating condition than in the other conditions ( P < 0.001 ). Seating 3D-printed prosthesis on the stone model reduces adverse deformation in the postcuring process, thereby enabling the fabrication of prostheses with favorable adaptation.

Investigation of three-dimensional printing materials for printing aorta model replicating Type B aortic dissection

2021 ◽  
Vol 17 ◽  
Author(s):  
Chia-An Wu ◽  
Andrew Squelch ◽  
Zhonghua Sun
Keyword(s):  
3D Printing ◽  
Aortic Dissection ◽  
Three Dimensional ◽  
Ct Images ◽  
Patient Specific ◽  
Type B ◽  
Type B Aortic Dissection ◽  
Ct Attenuation ◽  
Significant Difference ◽  
3D Printed

Aim: To determine a printing material that has both elastic property and radiology equivalence close to real aorta for simulation of endovascular stent graft repair of aortic dissection. Background: With the rapid development of three-dimensional (3D) printing technology, a patient-specific 3D printed model is able to help surgeons to make better treatment plan for Type B aortic dissection patients. However, the radiological properties of most 3D printing materials have not been well characterized. This study aims to investigate the appropriate materials for printing human aorta with mechanical and radiological properties similar to the real aortic computed tomography (CT) attenuation. Objective: Quantitative assessment of CT attenuation of different materials used in 3D printed models of aortic dissection for developing patient-specific 3D printed aorta models to simulate type B aortic dissection. Method: A 25-mm length of aorta model was segmented from a patient’s image dataset with diagnosis of type B aortic dissection. Four different elastic commercial 3D printing materials, namely Agilus A40 and A50, Visijet CE-NT A30 and A70 were selected and printed with different hardness. Totally four models were printed out and conducted CT scanned twice on a 192-slice CT scanner using the standard aortic CT angiography protocol, with and without contrast inside the lumen.Five reference points with region of interest (ROI) of 1.77 mm2 were selected at the aortic wall and intimal flap and their Hounsfield units (HU) were measured and compared with the CT attenuation of original CT images. The comparison between the patient’s aorta and models was performed through a paired-sample t-test to determine if there is any significant difference. Result: The mean CT attenuation of aortic wall of the original CT images was 80.7 HU. Analysis of images without using contrast medium showed that the material of Agilus A50 produced the mean CT attenuation of 82.6 HU, which is similar to that of original CT images. The CT attenuation measured at images acquired with other three materials was significantly lower than that of original images (p<0.05). After adding contrast medium, Visijet CE-NT A30 had an average CT attenuation of 90.6 HU, which is close to that of the original images with statistically significant difference (p>0.05). In contrast, the CT attenuation measured at images acquired with other three materials (Agilus A40, A50 and Visiject CE-NT A70) was 129 HU, 135 HU and 129.6 HU, respectively, which is significantly higher than that of original CT images (p<0.05). Conclusion: Both Visijet CE-NT and Agilus have tensile strength and elongation close to real patient’s tissue properties producing similar CT attenuation. Visijet CE-NT A30 is considered the appropriate material for printing aorta to simulate contrast-enhanced CT imaging of type B aortic dissection. Due to lack of body phantom in the experiments, further research with simulation of realistic anatomical body environment should be conducted.

scholarly journals Development of Soft sEMG Sensing Structures Using 3D-Printing Technologies

Sensors ◽  
2020 ◽  
Vol 20 (15) ◽  
pp. 4292
Author(s):  
Gerjan Wolterink ◽  
Pedro Dias ◽  
Remco G. P. Sanders ◽  
Frodo Muijzer ◽  
Bert-Jan van Beijnum ◽  
...  
Keyword(s):  
3D Printing ◽  
Biceps Brachii ◽  
Low Cost ◽  
Recognition Algorithm ◽  
Practical Applications ◽  
Variable Level ◽  
Processing Step ◽  
Significant Difference ◽  
3D Printed ◽  
Emg Electrodes

3D printing of soft EMG sensing structures enables the creation of personalized sensing structures that can be potentially integrated in prosthetic, assistive and other devices. We developed and characterized flexible carbon-black doped TPU-based sEMG sensing structures. The structures are directly 3D-printed without the need for an additional post-processing step using a low-cost, consumer grade multi-material FDM printer. A comparison between the gold standard Ag/AgCl gel electrodes and the 3D-printed EMG electrodes with a comparable contact area shows that there is no significant difference in the EMG signals’ amplitude. The sensors are capable of distinguishing a variable level of muscle activity of the biceps brachii. Furthermore, as a proof of principle, sEMG data of a 3D-printed 8-electrode band are analyzed using a patten recognition algorithm to recognize hand gestures. This work shows that 3D-printed sEMG electrodes have great potential in practical applications.

scholarly journals Comparison of Intaglio Surface Trueness of Interim Dental Crowns Fabricated with SLA 3D Printing, DLP 3D Printing, and Milling Technologies

Healthcare ◽  
2021 ◽  
Vol 9 (8) ◽  
pp. 983
Author(s):  
Keunbada Son ◽  
Jung-Ho Lee ◽  
Kyu-Bok Lee
Keyword(s):  
3D Printing ◽  
Computer Aided Design ◽  
Reference Model ◽  
Digital Light Processing ◽  
3 Dimensional ◽  
Dental Crowns ◽  
Test Models ◽  
Significant Difference ◽  
Manufacturing Accuracy ◽  
Aided Design

This study aimed to evaluate the intaglio surface trueness of interim dental crowns fabricated with three 3-dimensional (3D) printing and milling technologies. Dental crown was designated and assigned as a computer-aided design (CAD) reference model (CRM). Interim dental crowns were fabricated based on CRM using two types of 3D printer technologies (stereolithography apparatus and digital light processing) and one type of milling machine (n = 15 per technology). The fabricated interim dental crowns were obtained via 3D modeling of the intaglio surface using a laboratory scanner and designated as CAD test models (CTMs). The alignment and 3D comparison of CRM and CTM were performed based on the intaglio surface using a 3D inspection software program (Geomagic Control X). Statistical analysis was validated using one-way analysis of variance and Tukey HSD test (α = 0.05). There were significant differences in intaglio surface trueness between the three different fabrication technologies, and high trueness values were observed in the milling group (p < 0.05). In the milling group, there was a significant difference in trueness according to the location of the intaglio surface (p < 0.001). In the manufacturing process of interim dental crowns, 3D printing technologies showed superior and uniform manufacturing accuracy than milling technology.

scholarly journals Data driven design: An investigation into the fit between the individuality of people and the uniformity of mass manufactured items

2021 ◽  
Author(s):  
◽  
Alex Svend Christensen
Keyword(s):  
3D Printing ◽  
3D Scanning ◽  
Digital Data ◽  
Human Form ◽  
3 Dimensional ◽  
Manufacturing Efficiency ◽  
3D Printed ◽  
Body Shapes ◽  
The Individual ◽  
Motorcycle Rider

<p>Due to the economic advantage of mass manufacturing technology humans have designed a world of products built for the average body size and shape. This conformity of diverse body shapes to fixed 3 dimensional forms raises the question for this research; how can 3D scanning and additive manufacturing (AM) create a personal fit between an individual’s body and a product?  This question challenges a tool driven standardised approach to manufacture by exploring the interface between a person and a mass produced product, in this case a motorcycle rider and a motorcycle. By taking advantage of digital data and the tool-less build process of 3D printing, every object produced can be different, tailoring it to the customer’s individual aesthetic or physical fit.  This investigation into the space between the motorcycle and the human has produced a custom 3D printed seat designed for and inspired by the unique physicality of the individual rider. The following methods are employed. 3D scanning is used to obtain the geometry of the human form and motorcycle, 3D modelling and 3D printing to generate and evaluate ideas and concepts, and a pressure measurement system to evaluate the riders comfort and fit.  This new relationship between body and object, rarely seen in mass produced products, questions the way we design and make products with consideration towards digital personalisation and manufacturing efficiency.</p>

scholarly journals Development of a 3-dimensional printed tube thoracostomy task trainer: An improved methodology

2021 ◽  
Vol 6 (1) ◽  
pp. 109-113
Author(s):  
Wen Hao Chen ◽  
Shairah Radzi ◽  
Li Qi Chiu ◽  
Wai Yee Yeong ◽  
Sreenivasulu Reddy Mogali
Keyword(s):  
3D Printing ◽  
Chest Tube ◽  
Fused Deposition Modelling ◽  
3 Dimensional ◽  
Fused Deposition ◽  
Simulation Based ◽  
3D Printed ◽  
Medical Educators ◽  
Based Instruction ◽  
Training Modalities

Introduction: Simulation-based training has become a popular tool for chest tube training, but existing training modalities face inherent limitations. Cadaveric and animal models are limited by access and cost, while commercial models are often too costly for widespread use. Hence, medical educators seek a new modality for simulation-based instruction. 3D printing has seen growing applications in medicine, owing to its advantages in recreating anatomical detail using readily available medical images. Methods: Anonymised computer tomography data of a patient’s thorax was processed using modelling software to create a printable model. Compared to a previous study, 3D printing was applied extensively to this task trainer. A mixture of fused deposition modelling and material jetting technology allowed us to introduce superior haptics while keeping costs low. Given material limitations, the chest wall thickness was reduced to preserve the ease of incision and dissection. Results: The complete thoracostomy task trainer costs approximately SGD$130 (or USD$97), which is significantly cheaper compared to the average commercial task trainer. It requires approximately 118 hours of print time. The complete task trainer simulates the consistencies of ribs, intercostal muscles and skin. Conclusion: By utilising multiple 3D printing technologies, this paper aims to outline an improved methodology to produce a 3D printed chest tube simulator. An accurate evaluation can only be carried out after we improve on the anatomical fidelity of this prototype. A 3D printed task trainer has great potential to provide sustainable simulation-based education in the future.

scholarly journals 3D Printing Custom Bioactive and Absorbable Surgical Screws, Pins, and Bone Plates for Localized Drug Delivery

2019 ◽  
Vol 10 (2) ◽  
pp. 17 ◽  
Author(s):  
Karthik Tappa ◽  
Udayabhanu Jammalamadaka ◽  
Jeffery Weisman ◽  
David Ballard ◽  
Dallas Wolford ◽  
...  
Keyword(s):  
Drug Delivery ◽  
3D Printing ◽  
Flexural Strength ◽  
Bone Plates ◽  
Patient Specific ◽  
Fixation Devices ◽  
Significant Difference ◽  
3D Printed ◽  
Localized Drug Delivery ◽  
Orthopedic Applications

Additive manufacturing has great potential for personalized medicine in osseous fixation surgery, including maxillofacial and orthopedic applications. The purpose of this study was to demonstrate 3D printing methods for the fabrication of patient-specific fixation implants that allow for localized drug delivery. 3D printing was used to fabricate gentamicin (GS) and methotrexate (MTX)-loaded fixation devices, including screws, pins, and bone plates. Scaffolds with different infill ratios of polylactic acid (PLA), both without drugs and impregnated with GS and MTX, were printed into cylindrical and rectangular-shaped constructs for compressive and flexural strength mechanical testing, respectively. Bland PLA constructs showed significantly higher flexural strength when printed in a Y axis at 100% infill compared to other axes and infill ratios; however, there was no significant difference in flexural strength between other axes and infill ratios. GS and MTX-impregnated constructs had significantly lower flexural and compressive strength as compared to the bland PLA constructs. GS-impregnated implants demonstrated bacterial inhibition in plate cultures. Similarly, MTX-impregnated implants demonstrated a cytotoxic effect in osteosarcoma assays. This proof of concept work shows the potential of developing 3D printed screws and plating materials with the requisite mechanical properties and orientations. Drug-impregnated implants were technically successful and had an anti-bacterial and chemotherapeutic effect, but drug addition significantly decreased the flexural and compressive strengths of the custom implants.

scholarly journals Development of Smartphone-Controlled Hand and Arm Exoskeleton for Persons with Disability

2020 ◽  
Vol 11 (1) ◽  
pp. 161-170
Author(s):  
J-R. R. Diego ◽  
Dan William C. Martinez ◽  
Gerald S. Robles ◽  
John Ryan C. Dizon
Keyword(s):  
3D Printing ◽  
Low Cost ◽  
Three Dimensional ◽  
Prosthetic Device ◽  
Three Dimensional Printing ◽  
Plastic Materials ◽  
3D Printed ◽  
Available Technology ◽  
Electronic Parts ◽  
Dimensional Printing

AbstractThis study addresses the need for assistive technology of people who lost control of their upper limbs as well as people who are undergoing rehabilitation. Loss of upper limb control causes lack of functionality and social acceptability especially for many people in developing countries with fewer available technology. The study develops a modern but low-cost prosthetic device that can be controlled by users using a smartphone and can be rapidly manufactured using three-dimensional printing (3D printing) of plastic materials. The development of the prosthetic device includes designing the mechanical and electronic parts, programming the Arduino board and Android application for control, simulation and analysis of 3D printed parts most subjected to stress, and 3D printing the parts under different settings. The device was tested in terms of time spent and capacity of lifting varying loads when not worn and when worn by users. The device can effectively lift 500 grams of load in one second for a person weighing between 50 to 60 kilograms.

scholarly journals Innovative design of 3D-printed nasopharyngeal pediatric swab for COVID-19 detection

2021 ◽  
Vol 7 (1) ◽  
Author(s):  
Ameerah Alazemi ◽  
Ghadeer AbdulHussain ◽  
Abdullah Alawwam ◽  
Ali Al-Shatti ◽  
Mohammad Alghounaim ◽  
...  
Keyword(s):  
3D Printing ◽  
Nasopharyngeal Swab ◽  
High Demand ◽  
Innovative Design ◽  
Clinical Specimens ◽  
3 Dimensional ◽  
3D Printing Technology ◽  
Nasal Swabs ◽  
3D Printed ◽  
Upper Respiratory

Abstract3-dimensional (3D) printing technology provides a solution to meet the high demand for producing adult nasal swabs. A smaller, more flexible nasopharyngeal swab needs to be developed for children and infants suspected of having coronavirus. The information shared here presents a novel 3D-printed pediatric swab for the purpose of collecting upper respiratory clinical specimens.

scholarly journals Flexural Strength of 3D-Printing Resin Materials for Provisional Fixed Dental Prostheses

Materials ◽  
2020 ◽  
Vol 13 (18) ◽  
pp. 3970
Author(s):  
Sang-Mo Park ◽  
Ji-Man Park ◽  
Seong-Kyun Kim ◽  
Seong-Joo Heo ◽  
Jai-Young Koak
Keyword(s):  
3D Printing ◽  
Flexural Strength ◽  
Computer Aided Design ◽  
Testing Machine ◽  
Fused Deposition ◽  
Fixed Dental Prosthesis ◽  
Dental Prostheses ◽  
Significant Difference ◽  
Fixed Dental Prostheses ◽  
3D Printed

The clinical application of 3D-printed provisional restorations is increasing due to expansion of intraoral scanners, easy dental computer-aided design (CAD) software, and improved 3D printing speed. This study compared flexural strength of 3D-printed three-unit fixed dental prostheses with that of conventionally fabricated and milled restorations. A metal jig of two abutments and pontic space and an indenter for flexural strength measurement were fabricated. A three-unit fixed dental prosthesis was designed and manufactured using three additive manufacturing technologies, with subtractive manufacturing and a conventional method as controls. Digital light processing (DLP) group specimens were prepared from a polymethyl methacrylate (PMMA)-based resin and printed with a DLP printer. Stereolithography (SLA) group specimens were prepared from PMMA-based resin and printed with an SLA printer, and fused deposition modeling (FDM) group specimens were from a polylactic acid-based resin and printed with an FDM printer. Flexural strength was investigated using a universal testing machine, and the results were statistically analyzed. DLP and SLA groups had significantly higher flexural strength than the conventional group (p < 0.001). No significant difference was observed in flexural strength between DLP and SLA groups. The FDM group showed only dents but no fracture. The results of this study suggest that provisional restorations fabricated by DLP and SLA technologies provide adequate flexural strength for dental use.

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