scholarly journals 3D Printing Improved Testicular Prostheses: Using Lattice Infill Structure to Modify Mechanical Properties

2021 ◽  
Vol 8 ◽  
Author(s):  
Jacob Skewes ◽  
Michael Y. Chen ◽  
David Forrestal ◽  
Nicholas J. Rukin ◽  
Maria A. Woodruff
Keyword(s):  
Mechanical Properties ◽  
3D Printing ◽  
3D Model ◽  
Patient Specific ◽  
Shore Hardness ◽  
Elastomeric Material ◽  
Hardness Tests ◽  
3D Printed ◽  
Manufacturing Methods ◽  
Materials Used

Patients often opt for implantation of testicular prostheses following orchidectomy for cancer or torsion. Recipients of testicular prostheses report issues regarding firmness, shape, size, and position, aspects of which relate to current limitations of silicone materials used and manufacturing methods for soft prostheses. We aim to create a 3D printable testicular prosthesis which mimics the natural shape and stiffness of a human testicle using a lattice infill structure. Porous testicular prostheses were engineered with relative densities from 0.1 to 0.9 using a repeating cubic unit cell lattice inside an anatomically accurate testicle 3D model. These models were printed using a multi-jetting process with an elastomeric material and compared with current market prostheses using shore hardness tests. Additionally, standard sized porous specimens were printed for compression testing to verify and match the stiffness to human testicle elastic modulus (E-modulus) values from literature. The resulting 3D printed testicular prosthesis of relative density between 0.3 and 0.4 successfully achieved a reduction of its bulk compressive E-modulus from 360 KPa to a human testicle at 28 Kpa. Additionally, this is the first study to quantitatively show that current commercial testicular prostheses are too firm compared to native tissue. 3D printing allows us to create metamaterials that match the properties of human tissue to create customisable patient specific prostheses. This method expands the use cases for existing biomaterials by tuning their properties and could be applied to other implants mimicking native tissues.

3D printing of biofiber-reinforced composites and their mechanical properties: a review

2020 ◽  
Vol 26 (6) ◽  
pp. 1113-1129
Author(s):  
Lai Jiang ◽  
Xiaobo Peng ◽  
Daniel Walczyk
Keyword(s):  
Mechanical Properties ◽  
3D Printing ◽  
Reinforced Composites ◽  
Research Directions ◽  
Content Type ◽  
Reinforced Composite ◽  
3D Printed ◽  
Materials Used ◽  
Printing Processes ◽  
Pure Resin

Purpose This paper aims to summarize the up-to-date research performed on combinations of various biofibers and resin systems used in different three-dimensional (3D) printing technologies, including powder-based, material extrusion, solid-sheet and liquid-based systems. Detailed information about each process, including materials used and process design, are described, with the resultant products’ mechanical properties compared with those of 3D-printed parts produced from pure resin or different material combinations. In most processes introduced in this paper, biofibers are beneficial in improving the mechanical properties of 3D-printed parts and the biodegradability of the parts made using these green materials is also greatly improved. However, research on 3D printing of biofiber-reinforced composites is still far from complete, and there are still many further studies and research areas that could be explored in the future. Design/methodology/approach The paper starts with an overview of the current scenario of the composite manufacturing industry and then the problems of advanced composite materials are pointed out, followed by an introduction of biocomposites. The main body of the paper covers literature reviews of recently emerged 3D printing technologies that were applied to biofiber-reinforced composite materials. This part is classified into subsections based on the form of the starting materials used in the 3D printing process. A comprehensive conclusion is drawn at the end of the paper summarizing the findings by the authors. Findings Most of the biofiber-reinforced 3D-printed products exhibited improved mechanical properties than products printed using pure resin, indicating that biofibers are good replacements for synthetic ones. However, synthetic fibers are far from being completely replaced by biofibers due to several of their disadvantages including higher moisture absorbance, lower thermal stability and mechanical properties. Many studies are being performed to solve these problems, yet there are still some 3D printing technologies in which research concerning biofiber-reinforced composite parts is quite limited. This paper unveils potential research directions that would further develop 3D printing in a sustainable manner. Originality/value This paper is a summary of attempts to use biofibers as reinforcements together with different resin systems as the starting material for 3D printing processes, and most of the currently available 3D printing techniques are included herein. All of these attempts are solutions to some principal problems with current 3D printing processes such as the limit in the variety of materials and the poor mechanical performance of 3D printed parts. Various types of biofibers are involved in these studies. This paper unveils potential research directions that would further widen the use of biofibers in 3D printing in a sustainable manner.

Metallographic and Fractographic Evaluation of 3D-Printed Titanium Samples to Eliminate Unsatisfactory Mechanical Properties

2017 ◽  
Vol 270 ◽  
pp. 212-217
Author(s):  
Michaela Fousová ◽  
Tereza Stejskalova ◽  
Dalibor Vojtěch
Keyword(s):  
Mechanical Properties ◽  
Titanium Alloy ◽  
3D Printing ◽  
Process Parameters ◽  
Patient Specific ◽  
Medical Implants ◽  
Laser Melting ◽  
Patient Specific Implants ◽  
3D Printed ◽  
Set Up

Czech company ProSpon spol. s r.o. has introduced 3D printing technology in its production in 2015. This company operates in the field of development, manufacture and distribution of medical implants and instruments for orthopedics, traumatology and surgery. Therefore, the current intention is to employ Selective Laser Melting (SLM) technology for production of complex and patient-specific implants from titanium alloy Ti-6Al-4V. Nevertheless, first series of produced test specimens suffered from very low plasticity insufficient for the intended application. The reduction in elongation was almost 7fold compared to conventionally used wrought standard. From that reason, specimens were subjected to fractographic evaluation of fracture surfaces, but also metallographic evaluation. The main cause of the identified problem turned out to be porosity originating from inappropriate set-up of the machine. After the adjustment of process parameters new series of specimens were prepared in which the porosity was already significantly lower. Consequently, mechanical properties reached higher and better values.

DLP 3D printing of Dexamethasoneincorporated PEGDA-based photopolymers: compressive properties and drug release

2020 ◽  
Vol 6 (3) ◽  
pp. 406-409
Author(s):  
Robert Mau ◽  
Thomas Reske ◽  
Thomas Eickner ◽  
Niels Grabow ◽  
Hermann Seitz
Keyword(s):  
Mechanical Properties ◽  
3D Printing ◽  
Drug Release ◽  
Drug Loading ◽  
Patient Specific ◽  
Burst Release ◽  
Compressive Properties ◽  
Drug Load ◽  
Polyethylene Glycol Diacrylate ◽  
3D Printed

AbstractPhotopolymerizing, high-resolution 3D printing methods such as Stereolithography (SLA) or Digital Light Processing (DLP) are very promising for the manufacturing of drug-incorporated, patient specific implants. However, a drug-load may be limited by adequately solubility of the active pharmaceutical ingredient (API) in the photopolymer. Furthermore, a drug-load may affect the mechanical properties of the material negatively. Here, we investigate the DLP 3D printing of drugincorporated photopolymers. Polyethylene glycol diacrylate (PEGDA, Mn = 700 g/mol) is used as matrix polymer and Dexamethasone (DEX) is used for drug-loading (10 g/L and 20 g/L). Compressive properties, drug release and drug stability of 3D printed test samples were analyzed. DEX was found to be sparingly soluble in the PEGDA-based photopolymer. Not all drug particles can be dissolved at a concentration of 20 g/L and a slurry-like suspension is formed. Drug-incorporated photopolymers of 10 g/L (solution) and 20 g/L (suspension) were processed successfully via DLP. The higher the drug-load, the lower the compressive strength. Mechanical properties can be improved via a post-curing in a UV light curing box. Drug-incorporated 3D printed test samples show burst-release of DEX. The post-curing process does not affect drug release. DEX degrades in 3D-printed test samples significantly (~ 30 %) over a several days time period.

scholarly journals Point-of-care 3D printing: a low-cost approach to teaching carotid artery stenting

2021 ◽  
Vol 7 (1) ◽  
Author(s):  
Pieter De Backer ◽  
Charlotte Allaeys ◽  
Charlotte Debbaut ◽  
Roel Beelen
Keyword(s):  
Patient Education ◽  
3D Printing ◽  
Carotid Artery ◽  
Carotid Artery Stenting ◽  
3D Model ◽  
Low Cost ◽  
Patient Specific ◽  
Stent Deployment ◽  
Invasive Approach ◽  
3D Printed

Abstract Background Carotid Artery Stenting (CAS) is increasingly being used in selected patients as a minimal invasive approach to carotid endarterectomy. Despite the long standing tradition of endovascular treatments, visual feedback during stent-deployment is impossible to obtain as deployment is performed under fluoroscopic imaging. Furthermore, the concept of stent-placement is often still unclear to patients. 3D Printing allows to replicate patient-specific anatomies and deploy stents inside them to simulate procedures. As such these models are being used for endovascular training as well as patient education. Purpose To our knowledge, this study reports the first use of a low-cost patient-specific 3D printed model for teaching CAS deployment under direct visualization, without fluoroscopy. Methodology A CT-angiogram was segmented and converted to STL format using Mimics inPrint™ software. The carotid arteries were bilaterally truncated to fit the whole model on a Formlabs 2 printer without omitting the internal vessel diameter. Next, this model was offset using a 1 mm margin. A ridge was modelled on the original vessel anatomy which was subsequently subtracted from the offset model in order to obtain a deroofed 3D model. All vessels were truncated to facilitate post-processing, flow and guide wire placement. Results Carotid artery stents were successfully deployed inside the vessel. The deroofing allows for clear visualization of the bottlenecks and characteristics of CAS deployment and positioning, including stent foreshortening, tapering and recoil. This low-cost 3D model provides visual insights in stent deployment and positioning, and can allow for patient-specific procedure planning. Conclusions The presented approach demonstrates the use of low-cost 3D Printed CAS models in teaching complex stent behavior as observed during deployment. Two main findings are illustrated. On one hand, the feasibility of low-cost in-hospital model production is shown. On the other hand, the teaching of CAS deployment bottlenecks at the carotid level without the need for fluoroscopic guidance, is illustrated. The observed stent characteristics as shown during deployment are difficult to assess in radiologic models. Furthermore, printing patient-specific 3D models preoperatively could possibly assist in accurate patient selection, preoperative planning, case-specific training and patient education.

scholarly journals Design of thermoformable three dimensional-printed PLA cast for fractured wrist

2022 ◽  
Vol 1217 (1) ◽  
pp. 012002
Author(s):  
N P Sorimpuk ◽  
W H Choong ◽  
B L Chua
Keyword(s):  
Mechanical Properties ◽  
3D Printing ◽  
Three Dimensional ◽  
Maximum Load ◽  
Production Method ◽  
Patient Specific ◽  
Element Analysis ◽  
Plaster Of Paris ◽  
3D Printed ◽  
Printing Method

Abstract Patient specific plastic cast for broken limbs has been developed recently in pharmaceutical field through three-dimensional (3D) printing method. However, the production of a 3D printed cast through normal 3D printing method is time consuming compared to conventional plaster casting. In this study, a design of ventilated structured thermoformable 3D-printed polylactic acid (PLA) cast was produced as an alternative for the 3D printed cast production method. This design was initially printed in a flat shape and then transformed into a cast which can be fitted to the user’s arm by using heat and external force. Finite Element Analysis (FEA) method was used to assess the mechanical properties of the proposed cast. In this analysis, thethermoformable design was exerted with a distributed force of 400 N, which is larger than the loading conditions encountered by human in their daily life. The mechanical properties of the thermoformable PLA cast such as local displacement under a specific load, maximum load, and stress were evaluated. Results were compared with the mechanical properties of Plaster of Paris cast. The results obtained from the FEA indicates that at the same layer thickness, the thermoformable 3D-printed PLA cast is stronger than the Plaster of Paris cast.

scholarly journals Mechanical Properties and Biocompatibility of Urethane Acrylate-Based 3D-Printed Denture Base Resin

Polymers ◽  
2021 ◽  
Vol 13 (5) ◽  
pp. 822
Author(s):  
Jy-Jiunn Tzeng ◽  
Tzu-Sen Yang ◽  
Wei-Fang Lee ◽  
Hsuan Chen ◽  
Hung-Ming Chang
Keyword(s):  
Mechanical Properties ◽  
3D Printing ◽  
Flexural Modulus ◽  
Measurement Data ◽  
Uv Exposure ◽  
Control Group ◽  
Urethane Acrylate ◽  
Shore Hardness ◽  
Digital Light Processing ◽  
Denture Base

In this study, five urethane acrylates (UAs), namely aliphatic urethane hexa-acrylate (87A), aromatic urethane hexa-acrylate (88A), aliphatic UA (588), aliphatic urethane triacrylate diluted in 15% HDD (594), and high-functional aliphatic UA (5812), were selected to formulate five UA-based photopolymer resins for digital light processing (DLP)-based 3D printing. Each UA (40 wt%) was added and blended homogenously with ethoxylated pentaerythritol tetraacrylate (40 wt%), isobornyl acrylate (12 wt%), diphenyl (2,4,6-trimethylbenzoyl) phosphine oxide (3 wt%), and a pink acrylic (5 wt%). Each UA-based resin specimen was designed using CAD software and fabricated using a DLP 3D printer to specific dimensions. Characteristics, mechanical properties, and cytotoxicity levels of these designed UA-based resins were investigated and compared with a commercial 3D printing denture base acrylic resin (BB base) control group at different UV exposure times. Shore hardness-measurement data and MTT assays were analyzed using a one-way analysis of variance with Bonferroni’s post hoc test, whereas viscosity, maximum strength, and modulus were analyzed using the Kruskal–Wallis test (α = 0.05). UA-based photopolymer resins with tunable mechanical properties were successfully prepared by replacing the UA materials and the UV exposure times. After 15 min of UV exposure, the 5812 and 594 groups exhibited higher viscosities, whereas the 88A and 87A groups exhibited lower viscosities compared with the BB base group. Maximum flexural strength, flexural modulus, and Shore hardness values also revealed significant differences among materials (p < 0.001). Based on MTT assay results, the UA-based photopolymer resins were nontoxic. In the present study, mechanical properties of the designed photopolymer resins could be adjusted by changing the UA or UV exposure time, suggesting that aliphatic urethane acrylate has good potential for use in the design of printable resins for DLP-type 3D printing in dental applications.

Mechanical Properties of 3D-Printed Wood-Plastic Composites

2018 ◽  
Vol 777 ◽  
pp. 499-507 ◽  
Author(s):  
Ossi Martikka ◽  
Timo Kärki ◽  
Qing Ling Wu
Keyword(s):  
Mechanical Properties ◽  
Composite Materials ◽  
3D Printing ◽  
Impact Strength ◽  
Polylactic Acid ◽  
Wood Plastic Composite ◽  
Wood Plastic Composites ◽  
Plastic Composite ◽  
Plastic Composites ◽  
3D Printed

3D printing has rapidly become popular in both industry and private use. Especially fused deposition modeling has increased its popularity due to its relatively low cost. The purpose of this study is to increase knowledge in the mechanical properties of parts made of wood-plastic composite materials by using 3D printing. The tensile properties and impact strength of two 3D-printed commercial wood-plastic composite materials are studied and compared to those made of pure polylactic acid. Relative to weight –mechanical properties and the effect of the amount of fill on the properties are also determined. The results indicate that parts made of wood-plastic composites have notably lower tensile strength and impact strength that those made of pure polylactic acid. The mechanical properties can be considered sufficient for low-stress applications, such as visualization of prototypes and models or decorative items.

Algorithm to Reduce Leading and Lagging in Conformal Direct-Print

2018 ◽  
Vol 140 (10) ◽  
Author(s):  
Morteza Vatani ◽  
Faez Alkadi ◽  
Jae-Won Choi
Keyword(s):  
Additive Manufacturing ◽  
3D Printing ◽  
3D Model ◽  
Three Dimensional ◽  
Motion Direction ◽  
B Spline ◽  
And Topology ◽  
Printing System ◽  
3D Printed ◽  
Printed Patterns

A novel additive manufacturing algorithm was developed to increase the consistency of three-dimensional (3D) printed curvilinear or conformal patterns on freeform surfaces. The algorithm dynamically and locally compensates the nozzle location with respect to the pattern geometry, motion direction, and topology of the substrate to minimize lagging or leading during conformal printing. The printing algorithm was implemented in an existing 3D printing system that consists of an extrusion-based dispensing module and an XYZ-stage. A dispensing head is fixed on a Z-axis and moves vertically, while the substrate is installed on an XY-stage and moves in the x–y plane. The printing algorithm approximates the printed pattern using nonuniform rational B-spline (NURBS) curves translated directly from a 3D model. Results showed that the proposed printing algorithm increases the consistency in the width of the printed patterns. It is envisioned that the proposed algorithm can facilitate nonplanar 3D printing using common and commercially available Cartesian-type 3D printing systems.

scholarly journals Effect of temperature on the mechanical properties of 3D-printed PLA tensile specimens

2018 ◽  
Vol 24 (8) ◽  
pp. 1337-1346 ◽  
Author(s):  
Marzio Grasso ◽  
Lyes Azzouz ◽  
Paula Ruiz-Hincapie ◽  
Mauro Zarrelli ◽  
Guogang Ren
Keyword(s):  
Mechanical Properties ◽  
3D Printing ◽  
Mechanical Test ◽  
Optical Microscope ◽  
Middle Part ◽  
Gauge Length ◽  
Effect Of Temperature ◽  
Content Type ◽  
Relevant Effect ◽  
3D Printed

Purpose Recent advancements of 3D printing technology have brought forward the interest for this technique in many engineering fields. This study aims to focus on mechanical properties of the polylactic acid (PLA) feeding material under different thermal conditions for a typical fusion deposition of 3D printer system. Design/methodology/approach Specimens were tested under static loading within the range 20ºC to 60ºC considering different infill orientations. The combined effect of temperature and filament orientation is investigated in terms of constitutive material parameters and final failure mechanisms. The difference between feeding system before and post-3D printing was also assessed by mechanical test on feeding filament to verify the thermal profile during the deposition phase. Findings The results in terms of Young’s modulus, ultimate tensile strength (UTS), strain at failure (εf) and stress at failure (σf) are presented and discussed to study the influence of process settings over the final deposited material. Fracture surfaces have been investigated using an optical microscope to link the phenomenological interpretation of the failure with the micro-mechanical behaviour. Experimental results show a strong correlation between stiffness and strength with the infill orientation and the temperature values. Moreover, a relevant effect is related to deformed geometry of the filament approaching glass transition region of the polymer according to the deposition orientation. Research limitations/implications The developed method can be applied to optimise the stiffness and strength of any 3D-printed composite according to the infill orientation. Practical implications To avoid the failure of specimens outside the gauge length, a previously proposed modification to the geometry was adopted. The geometry has a parabolic profile with a curvature of 1,000 mm tangent to the middle part of the specimen. Originality/value Several authors have reported the stiffness and strength of 3D-printed parts under static and ambient temperature for different build parameters. However, there is a lack of literature on the combination of the latter with the temperature effects on the mechanical properties which this paper covers.

scholarly journals DESIGN OF A 3D-PRINTED THREE-CLAW ROBOTIC GRIPPER END-EFFECTOR

2021 ◽  
Vol 11 (4) ◽  
pp. 70-79
Author(s):  
Dino Dominic Forte Ligutan ◽  
Argel Alejandro Bandala ◽  
Jason Limon Española ◽  
Richard Josiah Calayag Tan Ai ◽  
Ryan Rhay Ponce Vicerra ◽  
...  
Keyword(s):  
3D Printing ◽  
Polylactic Acid ◽  
Grip Force ◽  
Thermoplastic Polyurethane ◽  
Robotic Arm ◽  
End Effector ◽  
Design Considerations ◽  
3D Printed ◽  
Materials Used ◽  
Metal Work

The development of a novel 3D-printed three-claw robotic gripper shall be described in this paper with the goal of incorporating various design considerations. Such considerations include the grip reliability and stability, grip force maximization, wide object grasping capability. Modularization of its components is another consideration that allows its parts to be easily machined and reusable. The design was realized by 3D printing using a combination of tough polylactic acid (PLA) material and thermoplastic polyurethane (TPU) material. In practice, additional tolerances were also considered for 3D printing of materials to compensate for possible expansion or shrinkage of the materials used to achieve the required functionality. The aim of the study is to explore the design and eventually deploy the three-claw robotic gripper to an actual robotic arm once its metal work fabrication is finished.

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