A comparative analysis of the compression characteristics of a thermoplastic polyurethane 3D printed in four infill patterns for comfort applications

Purpose Most support surfaces in comfort applications and sporting equipment are made from pressure-relieving foam such as viscoelastic polyurethane. However, for some users, foam is not the best material as it acts as a thermal insulator and it may not offer adequate postural support. The additive manufacturing of such surfaces and equipment may alleviate these issues, but material and design investigation is needed to optimize the printing parameters for use in pressure relief applications. This study aims to assess the ability of an additive manufactured flexible polymer to perform similarly to a viscoelastic foam for use in comfort applications. Design/methodology/approach Three-dimensional (3D) printed samples of thermoplastic polyurethane (TPU) are tested in uniaxial compression with four different infill patterns and varying infill percentage. The behaviours of the samples are compared to a viscoelastic polyurethane foam used in various comfort applications. Findings Results indicate that TPU experiences an increase in strength with an increasing infill percentage. Findings from the study suggest that infill pattern impacts the compressive response of 3D printed material, with two-dimensional patterns inducing an elasto-plastic buckling of the cell walls in TPU depending on infill percentage. Such buckling may not be a beneficial property for comfort applications. Based on the results, the authors suggest printing from TPU with a low-density 3D infill, such as 5% gyroid. Originality/value Several common infill patterns are characterised in compression in this work, suggesting the importance of infill choices when 3D printing end-use products and design for manufacturing.

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A review on the role of 3D printing in the fight against COVID-19: safety and challenges

Rapid Prototyping Journal ◽

10.1108/rpj-08-2020-0198 ◽

2021 ◽

Vol ahead-of-print (ahead-of-print) ◽

Author(s):

Sapam Ningthemba Singh ◽

Vavilada Satya Swamy Venkatesh ◽

Ashish Bhalchandra Deoghare

Keyword(s):

Supply Chain ◽

3D Printing ◽

Three Dimensional ◽

Content Type ◽

Medical Supplies ◽

Future Challenges ◽

Safety And Reliability ◽

3D Printed ◽

Comprehensive Study

Purpose During the COVID-19 pandemic, the three-dimensional (3D) printing community is actively participating to address the supply chain gap of essential medical supplies such as face masks, face shields, door adapters, test swabs and ventilator valves. This paper aims to present a comprehensive study on the role of 3D printing during the coronavirus (COVID-19) pandemic, its safety and its challenges. Design/methodology/approach This review paper focuses on the applications of 3D printing in the fight against COVID-19 along with the safety and challenges associated with 3D printing to fight COVID-19. The literature presented in this paper is collected from the journal indexing engines including Scopus, Google Scholar, ResearchGate, PubMed, Web of Science, etc. The main keywords used for searches were 3D printing COVID-19, Safety of 3D printed parts, Sustainability of 3D printing, etc. Further possible iterations of the keywords were used to collect the literature. Findings The applications of 3D printing in the fight against COVID-19 are 3D printed face masks, shields, ventilator valves, test swabs, drug deliveries and hands-free door adapters. As most of these measures are implemented hastily, the safety and reliability of these parts often lacked approval. The safety concerns include the safety of the printed parts, operators and secondary personnel such as the workers in material preparation and transportation. The future challenges include sustainability of the process, long term supply chain, intellectual property and royalty-free models, etc. Originality/value This paper presents a comprehensive study on the applications of 3D printing in the fight against COVID-19 with emphasis on the safety and challenges in it.

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What we have achieved in the design of 3D printed metal implants for application in orthopedics? Personal experience and review

Rapid Prototyping Journal ◽

10.1108/rpj-10-2017-0205 ◽

2018 ◽

Vol 24 (8) ◽

pp. 1365-1379 ◽

Cited By ~ 3

Author(s):

Zuhao Li ◽

Chenyu Wang ◽

Chen Li ◽

Zhonghan Wang ◽

Fan Yang ◽

...

Keyword(s):

Personal Experience ◽

Three Dimensional ◽

High Patient Satisfaction ◽

Functional Rehabilitation ◽

Content Type ◽

Metal Implants ◽

Potential Development ◽

3D Printed ◽

Future Potential

PurposeThis paper aims to review the latest applications in terms of three-dimensional printed (3DP) metal implants in orthopedics, and, importantly, the design of 3DP metal implants through a series of cases operated at The Second Hospital of Jilin University were presented.Design/methodology/approachThis paper is available to practitioners who are use 3DP implants in orthopedics. This review began with the deficiency of traditional prostheses and basic concepts of 3DP implants. Then, representative 3DP clinical cases were summarized and compared, and the experiences using customized prostheses and directions for future potential development are also shown.FindingsThe results obtained from the follow-up of clinical applications of 3DP implants show that the 3D designed and printed metal implants could exhibit good bone defect matching, quick and safe joint functional rehabilitation as well as saving time in surgery, which achieved high patient satisfaction collectively.Originality/valueSingle center experiences of 3DP metal implants design were shared and the detailed technical points between various regions were compared and analyzed. In conclusion, the 3DP technology is infusive and will present huge potential to reform future orthopedic practice.

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Retracted Article: 3D printed highly flexible strain sensor based on TPU–graphene composite for feedback from high speed robotic applications

Journal of Materials Chemistry C ◽

10.1039/c8tc03423k ◽

2019 ◽

Vol 7 (16) ◽

pp. 4692-4701 ◽

Cited By ~ 13

Author(s):

Jahan Zeb Gul ◽

Memoon Sajid ◽

Kyung Hyun Choi

Keyword(s):

High Speed ◽

Thermoplastic Polyurethane ◽

Three Dimensional ◽

Strain Sensor ◽

Graphene Composite ◽

Retracted Article ◽

3D Printed ◽

Resistive Type ◽

Flexible Strain Sensor ◽

Robotic Applications

A novel, highly flexible and electrically resistive-type strain sensor with a special three-dimensional conductive network was 3D printed using a composite of conductive graphene pellets and flexible thermoplastic polyurethane (TPU) pellets.

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3D Printed Acetabular Cups for Total Hip Arthroplasty: A Review Article

Metals ◽

10.3390/met9070729 ◽

2019 ◽

Vol 9 (7) ◽

pp. 729 ◽

Cited By ~ 17

Author(s):

Dall’Ava ◽

Hothi ◽

Di Laura ◽

Henckel ◽

Hart

Keyword(s):

3D Printing ◽

Total Hip Arthroplasty ◽

Clinical Outcomes ◽

Hip Arthroplasty ◽

Three Dimensional ◽

Total Hip ◽

3D Printed ◽

Key Variables ◽

End Use ◽

Acetabular Components

Three-dimensional (3D) printed titanium orthopaedic implants have recently revolutionized the treatment of massive bone defects in the pelvis, and we are on the verge of a change from conventional to 3D printed manufacture for the mass production of millions of off-the-shelf (non-personalized) implants. The process of 3D printing has many adjustable variables, which taken together with the possible variation in designs that can be printed, has created even more possible variables in the final product that must be understood if we are to predict the performance and safety of 3D printed implants. We critically reviewed the clinical use of 3D printing in orthopaedics, focusing on cementless acetabular components used in total hip arthroplasty. We defined the clinical and engineering rationale of 3D printed acetabular cups, summarized the key variables involved in the manufacturing process that influence the properties of the final parts, together with the main limitations of this technology, and created a classification according to end-use application to help explain the controversial and topical issues. Whilst early clinical outcomes related to 3D printed cups have been promising, in-depth robust investigations are needed, partly because regulatory approval systems have not fully adapted to the change in technology. Analysis of both pristine and retrieved cups, together with long-term clinical outcomes, will help the transition to 3D printing to be managed safely.

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3D-Printed Soft Structure of Polyurethane and Magnetorheological Fluid: A Proof-of-Concept Investigation of its Stiffness Tunability

Micromachines ◽

10.3390/mi10100655 ◽

2019 ◽

Vol 10 (10) ◽

pp. 655 ◽

Cited By ~ 1

Author(s):

Seong-Woo Hong ◽

Ji-Young Yoon ◽

Seong-Hwan Kim ◽

Sun-Kon Lee ◽

Yong-Rae Kim ◽

...

Keyword(s):

Fused Deposition Modeling ◽

Permanent Magnets ◽

Thermoplastic Polyurethane ◽

Three Dimensional ◽

Magnetorheological Fluid ◽

Three Dimensional Printing ◽

Fused Deposition ◽

Deposition Modeling ◽

3D Printed ◽

Dimensional Printing

In this study, a soft structure with its stiffness tunable by an external field is proposed. The proposed soft beam structure consists of a skin structure with channels filled with a magnetorheological fluid (MRF). Two specimens of the soft structure are fabricated by three-dimensional printing and fused deposition modeling. In the fabrication, a nozzle is used to obtain channels in the skin of the thermoplastic polyurethane, while another nozzle is used to fill MRF in the channels. The specimens are tested by using a universal tensile machine to evaluate the relationships between the load and deflection under two different conditions, without and with permanent magnets. It is empirically shown that the stiffness of the proposed soft structure can be altered by activating the magnetic field.

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Custom Patient-Specific Three-Dimensional Printed Mitral Valve Models for Pre-Operative Patient Education Enhance Patient Satisfaction and Understanding

Journal of Medical Devices ◽

10.1115/1.4043737 ◽

2019 ◽

Vol 13 (3) ◽

Author(s):

Kay S. Hung ◽

Michael J. Paulsen ◽

Hanjay Wang ◽

Camille Hironaka ◽

Y. Joseph Woo

Keyword(s):

Patient Education ◽

Mitral Valve ◽

Three Dimensional ◽

3D Models ◽

Patient Specific ◽

Imaging Data ◽

Anatomical Models ◽

Mitral Valves ◽

Flexible Polymer ◽

3D Printed

In recent years, advances in medical imaging and three-dimensional (3D) additive manufacturing techniques have increased the use of 3D-printed anatomical models for surgical planning, device design and testing, customization of prostheses, and medical education. Using 3D-printing technology, we generated patient-specific models of mitral valves from their pre-operative cardiac imaging data and utilized these custom models to educate patients about their anatomy, disease, and treatment. Clinical 3D transthoracic and transesophageal echocardiography images were acquired from patients referred for mitral valve repair surgery and segmented using 3D modeling software. Patient-specific mitral valves were 3D-printed using a flexible polymer material to mimic the precise geometry and tissue texture of the relevant anatomy. 3D models were presented to patients at their pre-operative clinic visit and patient education was performed using either the 3D model or the standard anatomic illustrations. Afterward, patients completed questionnaires assessing knowledge and satisfaction. Responses were calculated based on a 1–5 Likert scale and analyzed using a nonparametric Mann–Whitney test. Twelve patients were presented with a patient-specific 3D-printed mitral valve model in addition to standard education materials and twelve patients were presented with only standard educational materials. The mean survey scores were 64.2 (±1.7) and 60.1 (±5.9), respectively (p = 0.008). The use of patient-specific anatomical models positively impacts patient education and satisfaction, and is a feasible method to open new opportunities in precision medicine.

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Soft-tissue-mimicking using silicones for the manufacturing of soft phantoms by fresh 3D printing

Rapid Prototyping Journal ◽

10.1108/rpj-04-2021-0079 ◽

2021 ◽

Vol ahead-of-print (ahead-of-print) ◽

Author(s):

Aitor Tejo-Otero ◽

Arthur Colly ◽

Edwin-Joffrey Courtial ◽

Felip Fenollosa-Artés ◽

Irene Buj-Corral ◽

...

Keyword(s):

Soft Tissue ◽

3D Printing ◽

Three Dimensional ◽

Mechanical Analysis ◽

Living Tissue ◽

Scanning Calorimetry ◽

Content Type ◽

Microscopy Analysis ◽

3D Printed ◽

Liver Phantom

Purpose The purpose of this study is to use the Freeform Reversible Embedding of Suspended Hydrogels (FRESH) additive manufacturing (AM) technique for manufacturing a liver phantom which can mimic the corresponding soft living tissue. One of the possible applications is surgical planning. Design/methodology/approach A thermo-reversible Pluronic® F-127-based support bath is used for the FRESH technique. To verify how three-dimensional (3D)-printed new materials can mimic liver tissue, dynamic mechanical analysis and oscillation shear rheometry tests are carried out to identify mechanical characteristics of different 3D printed silicone samples. Additionally, the differential scanning calorimetry was done on the silicone samples. Then, a validation of a 3D printed silicone liver phantom is performed with a 3D scanner. Finally, the surface topography of the 3D printed liver phantom was fulfiled and microscopy analysis of its surface. Findings Silicone samples were able to mimic the liver, therefore obtaining the first soft phantom of the liver using the FRESH technique. Practical implications Because of the use of soft silicones, surgeons could practice over these improved phantoms which have an unprecedented degree of living tissue mimicking, enhancing their rehearsal experience before surgery. Social implications An improvement in surgeons surgery skills would lead to a bettering in the patient outcome. Originality/value The first research study was carried out to mimic soft tissue and apply it to the 3D printing of organ phantoms using AM FRESH technique.

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Examining consumers' perceptions of a 3D printing integrated apparel: a functional, expressive and aesthetic (FEA) perspective

Journal of Fashion Marketing and Management ◽

10.1108/jfmm-02-2021-0036 ◽

2021 ◽

Vol ahead-of-print (ahead-of-print) ◽

Author(s):

Tianyu Cui ◽

Veena Chattaraman ◽

Lushan Sun

Keyword(s):

Purchase Intention ◽

Online Survey ◽

Three Dimensional ◽

Positive Influence ◽

Future Research ◽

Perceived Fit ◽

Content Type ◽

Future Studies ◽

Fea Model ◽

3D Printed

PurposeThis study adopted the functional, expressive and aesthetic (FEA) consumer needs model, aimed to examine the influence of consumers' FEA perceptions of three-dimensional printing (3DP) integrated apparel products on their product satisfaction and purchase intention.Design/methodology/approachAn online survey was employed with a sample of 332 participants (165 female and 167 male) aged 19 to 76, mean age of 35 years. A gender-neutral, 3DP integrated hooded sweatshirt was developed for this study featuring flexible, white 3D printed insets fabricated with an FDM 3D printer and white TPU filament sewn with traditional gray knit fleece.FindingsThe findings of this study suggest that the FEA model is appropriate in predicting consumers' satisfaction with 3DP integrated apparel products. Specifically, aesthetic (perceived beauty) and expressive (perceived coolness) dimensions are more influential than functional factors, except for the positive influence of perceived fit, in predicting consumers' satisfaction and purchase intentions for 3DP integrated apparel products.Research limitations/implicationsFuture studies could consider data collection from participants' physical fit testing or try on evaluation to determine the importance of the functional dimension in consumer response to 3DP integrated apparel product. Future studies could also examine full 3D printed apparel, or other 3DP integrated wearable products to expand the understanding of consumer perception of the application of 3DP technology.Originality/valueDespite the increasing exploration of 3DP integrated apparel products and industry attempts to make this innovation in apparel more mainstream, research on how mainstream consumers perceive such 3DP integrated apparel products is limited. This study addresses this gap, providing critical implications for future research and design.

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Multi-scale finite element modeling of 3D printed structures subjected to mechanical loads

Rapid Prototyping Journal ◽

10.1108/rpj-05-2016-0074 ◽

2018 ◽

Vol 24 (1) ◽

pp. 177-187 ◽

Cited By ~ 7

Author(s):

Dalia Calneryte ◽

Rimantas Barauskas ◽

Daiva Milasiene ◽

Rytis Maskeliunas ◽

Audrius Neciunas ◽

...

Keyword(s):

Finite Element ◽

Composite Structures ◽

Computational Models ◽

Three Dimensional ◽

Structural Response ◽

Content Type ◽

Multi Scale ◽

Macro Scale ◽

Internal Constitution ◽

3D Printed

Purpose The purpose of this paper is to investigate the influence of geometrical microstructure of items obtained by applying a three-dimensional (3D) printing technology on their mechanical strength. Design/methodology/approach Three-dimensional printed items (3DPI) are composite structures of complex internal constitution. The buildup of the finite element (FE) computational models of 3DPI is based on a multi-scale approach. At the micro-scale, the FE models of representative volume elements corresponding to different additive layer heights and different thicknesses of extruded fibers are investigated to obtain the equivalent non-linear nominal stress–strain curves. The obtained results are used for the creation of macro-scale FE models, which enable to simulate the overall structural response of 3D printed samples subjected to tensile and bending loads. Findings The validation of the models was performed by comparing the computed results against the experimental ones, where satisfactory agreement has been demonstrated within a marked range of thicknesses of additive layers. Certain inadequacies between computed against experimental results were observed in cases of thinnest and thickest additive layers. The principle explanation of the reasons of inadequacies takes into account the poorer quality of mutual adhesion in case of very thin extruded fibers and too-early solidification effect. Originality/value Flexural and tensile experiments are simulated by FE models that are created with consideration to microstructure of 3D printed samples.

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Fast production of customized three-dimensional-printed hand splints

Rapid Prototyping Journal ◽

10.1108/rpj-01-2019-0009 ◽

2020 ◽

Vol 26 (1) ◽

pp. 134-144 ◽

Cited By ~ 1

Author(s):

Diana Popescu ◽

Aurelian Zapciu ◽

Cristian Tarba ◽

Dan Laptoiu

Keyword(s):

3D Printing ◽

Three Dimensional ◽

Online Application ◽

Content Type ◽

3D Cad ◽

Aesthetic Appearance ◽

3D Printed ◽

Manufacturing Time ◽

Practical Implications

Purpose This paper aims to propose a new solution for producing customized three-dimensional (3D)-printed flat-shaped splints, which are then thermoformed to fit the patient’s hand. The splint design process is automated and is available to clinicians through an online application. Design/methodology/approach Patient anthropometric data measured by clinicians are associated with variables of parametric 3D splint models. Once these variables are input by clinicians in the online app, customized stereo lithography (STL) files for both splint and half mold, in the case of the bi-material splint, are automatically generated and become available for download. Bi-materials splints are produced by a hybrid manufacturing process involving 3D printing and overmolding. Findings This approach eliminates the need for 3D CAD-proficient clinicians, allows fast generation of customized splints, generates two-dimensional (2D) drawings of splints for verifying shape and dimensions before 3D printing and generates the STL files. Automation reduces splint design time and cost, while manufacturing time is diminished by 3D printing the splint in a flat position. Practical implications The app could be used in clinical practice. It meets the demands of mass customization using 3D printing in a field where individualization is mandatory. The solution is scalable – it can be extended to other splint designs or to other limbs. 3D-printed tailored splints can offer improved wearing comfort and aesthetic appearance, while maintaining hand immobilization, allowing visually controlled follow-up for edema and rapidly observing the need for revision if necessary. Originality/value An online application was developed for uploading patient measurements and downloading 2D drawings and STL files of customized splints. Different models of splints can be designed and included in the database as alternative variants. A method for producing bi-materials flat splints combining soft and rigid polymers represents another novelty of the research.

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