Effect of Three-Dimensional Printing With Nanotubes on Impact and Fatigue Resistance

Author(s):  
Anne Schmitz

Abstract The types of biomedical devices that can be three-dimensional printed (3DP) are limited by the mechanical properties of the resulting materials. As a result, much research has been focused on adding carbon nanotubes (CNT) to these photocurable polymers to make them stronger. The objective of this study was to expand the use of 3DP to prosthetics by testing the hypothesis that adding CNTs to a stereolithographic (SLA) photocurable resin will result in a cured polymer with increased impact and fatigue resistance. For impact testing, twenty-six total specimens, 13 with nanotubes and 13 without nanotubes, were printed on a Form2 SLA printer. Once all the specimens were printed, washed, and cured, the impact resistance was quantified using a pendulum impact tester using a notched Izod configuration. Similarly, twelve R. R. Moore fatigue specimens were printed, washed, and cured. The specimens with SWCNTs (0.312 ± 0.036 ft lb/in.) had a significantly lower impact resistance compared to the non-SWCNT specimens (0.364 ± 0.055 ft lb/in.), U = 34.0, p = 0.004. Adding SWCNTs also reduced the short cycle fatigue life (i.e., 103) from 3.1 × 5 to 8.8 × 3 psi and increased the endurance limit from 0.4 to 3.0 × 3 psi. If used for creating a foot prosthetic, the non-SWCNT polymer would last 2919 cycles while the SWCNT mixture would last <1 cycle. Therefore, SLA polymers do not yet have the impact and fatigue resistance capabilities to be used for prosthetic feet.

2019 ◽  
Author(s):  
Anne Schmitz

Abstract The types of biomedical devices that can be three-dimensional printed (3DP) is limited by the mechanical properties of the resulting materials. As a result, much research has focused on adding carbon nanotubes (CNT) to these photocurable polymers to make them stronger. However, there is little to no data on how CNTs affect the impact resistance of these polymers, an important property when designing and manufacturing lower limb prosthetics. The objective of this study was to expand the use of 3DP to prosthetics by testing the hypothesis that adding CNTs to a stereolithographic (SLA) photocurable resin will result in a cured polymer with increased impact resistance. Twenty-six total specimens: 13 with nanotubes and 13 without nanotubes, were printed on a Form2 SLA printer. Once all the specimens were printed, washed, and cured, the impact resistance was quantified using a pendulum impact tester in a notched Izod configuration. Contrary to the hypothesis, the specimens with SWCNTs (0.312 ± 0.036 ft*lb/in) had a significantly lower impact resistance compared to the non-SWCNT specimens (0.364 ± 0.055 ft*lb/in), U = 34.0, p = 0.004. This decreased impact resistance may be due to voids in the printed polymer around the aggregated nanotubes. Thus, SLA polymers still do not have the impact strength needed to be used for a full lower limb prosthetic.


Author(s):  
K. G. Siree ◽  
T. M. Amulya ◽  
T. M. Pramod Kumar ◽  
S. Sowmya ◽  
K. Divith ◽  
...  

Three-dimensional (3D) printing is a unique technique that allows for a high degree of customisation in pharmacy, dentistry and in designing of medical devices. 3D printing satiates the increasing exigency for consumer personalisation in these fields as custom-made medicines catering to the patients’ requirements are novel advancements in drug therapy. Current research in 3D printing indicates towards reproducing an organ in the form of a chip; paving the way for more studies and opportunities to perfecting the existing technique. In addition, we will also attempt to shed light on the impact of 3D printing in the COVID-19 pandemic.


2013 ◽  
Vol 747 ◽  
pp. 745-748
Author(s):  
Warangkhana Phromma ◽  
Rathanawan Magaraphan

Natural rubber (NR)/Polycaprolactone (PCL) core-shell (NR-ad-PCL), from admicellar polymerization, was as an impact modifier for the composites. PLA was mixed with NR-ad-PCL with different NR-ad-PCL contents at 5, 10, 15 and 20 wt%. PLA-based composites were prepared by co-rotating twin screw extruder. The morphology of the composites was observed by Field emission scanning electron microscope (FE-SEM). Mechanical properties of the composites were investigated by dynamic mechanical analyzer and pendulum impact tester. The impact strength of the PLA filled with NR-ad-PCL increased while modulus of the PLA composites decreased with increasing rubber contents.


2020 ◽  
pp. 103530462098142
Author(s):  
Al Rainnie

Before the COVID-19 pandemic erupted onto the world stage, a new narrative was apparently beginning to emerge about the impact of i4.0 and new technologies in general, and three-dimensional printing in particular, on the future of work and employment. This was to have particular geographical implications for the manufacturing sector in particular. Proponents of i4.0 also suggested that this process, particularly in manufacturing, would promote the re-emergence of patterns of clustering. Developments in advanced manufacturing, particularly three-dimensional printing, would accelerate and reinforce these tendencies. This article looks at the role that three-dimensional printing is supposed to play in the new world, and in particular, critically evaluates its role in reinforcing the trend towards deglobalisation on the one hand, and, on the other, new clusters of manufacturing industry. JEL code: O33


2020 ◽  
Vol 6 (11) ◽  
pp. eaay3499 ◽  
Author(s):  
Nathan Blanken ◽  
Muhammad Saeed Saleem ◽  
Carlo Antonini ◽  
Marie-Jean Thoraval

Drop impact on solid surfaces is encountered in numerous natural and technological processes. Although the impact of single-phase drops has been widely explored, the impact of compound drops has received little attention. Here, we demonstrate a self-lubrication mechanism for water-in-oil compound drops impacting on a solid surface. Unexpectedly, the core water drop rebounds from the surface below a threshold impact velocity, irrespective of the substrate wettability. This is interpreted as the result of lubrication from the oil shell that prevents contact between the water core and the solid surface. We combine side and bottom view high-speed imaging to demonstrate the correlation between the water core rebound and the oil layer stability. A theoretical model is developed to explain the observed effect of compound drop geometry. This work sets the ground for precise complex drop deposition, with a strong impact on two- and three-dimensional printing technologies and liquid separation.


Author(s):  
Anne Schmitz

Abstract Three-dimensional (3D) printing with high-resolution stereolithography (SLA) has grown in popularity for creating personalized medical devices. 3D printing is now starting to expand to weight-bearing components, e.g. prosthetic feet, as data on the dynamic properties impact and fatigue is published in the literature. The next step towards using 3D printing in impact applications is to assess the capability of the high-resolution SLA process to manufacture components of uniform impact resistance. Because impact testing is destructive, a surrogate measure to check a part's viability for resisting an impact load also needs to be established. Thirteen notched Izod specimens were printed on a Form2 SLA printer using the manufacturer's photocurable resins: clear, flexible, durable, and draft. Once all the specimens were printed, washed in isopropyl alcohol, and cured with ultraviolet light, the impact resistance was quantified using a pendulum impact tester in a notched Izod configuration. Then, the hardness of the specimens was quantified using a Shore durometer. The process capability indices of the impact resistance for the various polymers were 0.11 (clear), 0.43 (flexible), 0.65 (durable), and 1.07 (draft). Impact resistance and Shore durometer were only correlated for the flexible resin with a Spearman coefficient of r = 0.738, p &lt; 0.005. Since the process capability index was so variable across materials, 3D printing with SLA polymers is not a viable manufacturing process for creating parts of consistent impact resistance. The current technology would lead to too many rejected parts.


2009 ◽  
Vol 00 (00) ◽  
pp. 090730035508060-7
Author(s):  
Deng-Guang Yu ◽  
Chris Branford-White ◽  
Yi-Cheng Yang ◽  
Li-Min Zhu ◽  
Edward William Welbeck ◽  
...  

2020 ◽  
Vol 13 (12) ◽  
pp. e239286
Author(s):  
Kumar Nilesh ◽  
Prashant Punde ◽  
Nitin Shivajirao Patil ◽  
Amol Gautam

Ossifying fibroma (OF) is a rare, benign, fibro-osseous lesion of the jawbone characterised by replacement of the normal bone with fibrous tissue. The fibrous tissue shows varying amount of calcified structures resembling bone and/or cementum. The central variant of OF is rare, and shows predilection for mandible among the jawbone. Although it is classified as fibro-osseous lesion, it clinically behaves as a benign tumour and can grow to large size, causing bony swelling and facial asymmetry. This paper reports a case of large central OF of mandible in a 40-year-old male patient. The lesion was treated by segmental resection of mandible. Reconstruction of the surgical defect was done using avascular fibula bone graft. Role of three-dimensional printing of jaw and its benefits in surgical planning and reconstruction are also highlighted.


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