PLA

During the 3D printing process, around 15 % of the material used is wasted due to the supports and bases to generate the prototypes, attributing a problem for the environment and the economy of the users. Currently, do not exist a machine of low cost with can recycle the ABS and PLA filament of 3D printers and, in this way, reduce the operating costs of this type of machine, which is widely used in different industrial sectors for the manufacture of prototypes. Theories of mechanical design, heat transfer, and numerical analysis were used to calculate and analyze the most important elements to design the thermoforming machine made of recycled ABS and PLA material. Taking this into account, the machine will reduce printing costs, benefiting industries that use this type of material, with which they will be able to recycle and manufacture the printing material, 1 Universidad Francisco de Paula Santander Ocaña, (Colombia). Correo electrónico: ragarcial@ufpso.edu.co orcid: https//orcid....

Durante el proceso de impresión 3D, alrededor del 15 % del material utilizado es desperdiciado, debido a los soportes y bases para generar los prototipos, atribuyendo un problema para el ambiente y la economía de los usuarios. Actualmente, no existe una máquinade bajo costo con la que se pueda reciclar el filamento de acrilonitrilo butadieno estireno (ABS) yácido polilácticoopoliácido láctico (PLA) de las impresoras 3D, y asílograr disminuir los costos de operación de este tipo de máquinas que son de gran uso en sectores industriales para la fabricación de prototipos. Para el diseño de la máquina de termoconformados de material reciclado de ABS y PLA, se utilizaron teorías de diseño mecánico, transferencia de calor y análisis numérico para calcular y analizar los elementos más importantes. Teniendo en cuenta lo anterior, las industrias que utilizan este tipo de polímeros podrán reciclar y fabricar el material de impresión, optimizando, además, el proceso productivo, reduciendo los t...

3D Printing technology is slowly making its way into the mainstream manufacturing Processes. Fused Deposition Modelling (FDM) is one of the most popular techniques of manufacturing objects by 3D Printing. Under tension, two types of failure phenomenon occur in 3D printed specimen i.e. In-layer & Inter-layer fracture. In-layer fracture is considered to be a desirable failure type as it signifies that the layer separation is not occurring in the specimen and the fusion bond created is sufficiently strong which leads to superior tensile strength of the specimen. In this study, we have carried out experiments to study the effect process parameters like Nozzle Temperature, Printing speed & Rastor Angle has on the fusion bond between the layers by studying the angle made by the fractured surface with the layer. Poly Lactic Acid (PLA) material and FDM 3D Printing Method is used for making the testing specimens. Results showed that nozzle temperature & Rastor Angle have significant effect on tensile strength & In-layer fracture. Tensile strength was found to be increased with both increase in nozzle temperature & Rastor Angle. However, 40 mm/s is found to be the most suitable printing speed value. Using regression analysis, an equation to predict the type of failure for the given values of process parameters is given. 45 0 is found to be the critical rastor angle of separation for In-layer & Inter-layer fracture phenomenon. Keywords: Fuse Deposition Modelling, PLA, In-layer & Inter-layer fracture I. INTRODUCTION 3D printing technology in the last decade has seen lot of Research and progress being carried out in the field of additive manufacturing. The Cost and Time associated with the 3D printing process has reduced significantly in recent time with the emergence of new electronic technologies. With the operating cost of 3D printing reducing, it has caught the attention of lot of researchers to carry out study on the process. There are many printing technologies used in 3D printing. Fuse Deposition Modelling (FDM) has emerged as one of the most popular techniques for its ability to print objects with different polymers. Lots of studies are being carried out on the effects FDM 3D Printing Process parameters have on the mechanical properties of an object printed by FDM. Therefore it is necessary to evaluate how these mechanical properties of an object react to change in the process parameters. Different polymeric materials react differently to the change in process parameters. In this study, we have used Poly Lactic Acid (PLA) filament for the making the testing specimen. Numbers of specimen were printed using FDM Machine with varying Nozzle Temperature, Printing Speed, and Rastor angle.

Now a day, the 3D printing is an increasingly commercially used technology. A crucial section of 3D printing is for providing the printer with printable content if possible, which is achieved by using reels of plastic filament, the most common is PLA, but it is the final product which is sold separately. For this situation, the other option arises that plastic material can be recycled and reused through bottles which are disposable which were discarded in order to be used as printable material. 3D Printing Technology is also defined as rapid prototyping, where a 3-dimensional structure is formed by laying the specific material layers. Three phases such as design, printing & finishing are included here in this process. They use any CAD software in the first step to create 3d design. Use this template to build an object in the 2nd stage 3D printer. And the finished item of the third step is extracted from the printer. This technology saves time and money. This avoids material waste. It is very useful to give the demo of any product in industries.

The recent development of the RepRap, an open-source self-replicating rapid prototyper, has made 3-D polymer-based printers readily available to the public at low costs (<$500). The resultant uptake of 3-D printing technology enables for the first time mass-scale distributed digital manufacturing. RepRap variants currently fabricate objects primarily from acrylonitrile butadiene styrene (ABS) and polylactic acid (PLA), which have melting temperatures low enough to use in melt extrusion outside of a dedicated facility, while high enough for prints to retain their shape at average use temperatures. In order for RepRap printed parts to be useful for engineering applications the mechanical properties of printed parts must be known. This study quantifies the basic tensile strength and elastic modulus of printed components using realistic environmental conditions for standard users of a selection of open-source 3-D printers. The results find average tensile strengths of 28.5 MPa for ABS and 56.6 MPa for PLA with average elastic moduli of 1807 MPa for ABS and 3368 MPa for PLA. It is clear from these results that parts printed from tuned, low-cost, open-source RepRap 3-D printers can be considered as mechanically functional in tensile applications as those from commercial vendors.

3D Printing technology is slowly making its way into the mainstream manufacturing Processes. Fused Deposition Modelling (FDM) is one of the most popular techniques of manufacturing objects by 3D Printing. Under tension, two types of failure phenomenon occur in 3D printed specimen i.e. In-layer & Inter-layer fracture. In-layer fracture is considered to be a desirable failure type as it signifies that the layer separation is not occurring in the specimen and the fusion bond created is sufficiently strong which leads to superior tensile strength of the specimen. In this study, we have carried out experiments to study the effect process parameters like Nozzle Temperature, Printing speed & Rastor Angle has on the fusion bond between the layers by studying the angle made by the fractured surface with the layer. Poly Lactic Acid (PLA) material and FDM 3D Printing Method is used for making the testing specimens. Results showed that nozzle temperature & Rastor Angle have significant effect on tensile strength & In-layer fracture. Tensile strength was found to be increased with both increase in nozzle temperature & Rastor Angle. However, 40 mm/s is found to be the most suitable printing speed value. Using regression analysis, an equation to predict the type of failure for the given values of process parameters is given. 45 0 is found to be the critical rastor angle of separation for In-layer & Inter-layer fracture phenomenon. Keywords: Fuse Deposition Modelling, PLA, In-layer & Inter-layer fracture I. INTRODUCTION 3D printing technology in the last decade has seen lot of Research and progress being carried out in the field of additive manufacturing. The Cost and Time associated with the 3D printing process has reduced significantly in recent time with the emergence of new electronic technologies. With the operating cost of 3D printing reducing, it has caught the attention of lot of researchers to carry out study on the process. There are many printing technologies used in 3D printing. Fuse Deposition Modelling (FDM) has emerged as one of the most popular techniques for its ability to print objects with different polymers. Lots of studies are being carried out on the effects FDM 3D Printing Process parameters have on the mechanical properties of an object printed by FDM. Therefore it is necessary to evaluate how these mechanical properties of an object react to change in the process parameters. Different polymeric materials react differently to the change in process parameters. In this study, we have used Poly Lactic Acid (PLA) filament for the making the testing specimen. Numbers of specimen were printed using FDM Machine with varying Nozzle Temperature, Printing Speed, and Rastor angle.

The crystallization behavior of polylactide (PLA) with various branching degrees and nanoclay contents were investigated using a differential scanning calorimeter (DSC). The dispersion quality of nanoclay within PLA and reactivity of chain extender with PLA molecules were analyzed using X-ray diffraction (XRD) and Fourier transform infrared spectroscopy test (FT-IR), respectively.

The results showed that chain branching in PLA produced higher crystallinity and fastened its slow crystallization kinetics. Also, the effects of processing (i.e., the same compounding process through a twin-screw extruder as for the PLA nanocomposites) on the crystallinity of "as received" PLAs were investigated to better compare them with the PLA nanocomposites. The results showed that the addition of nanoclay in different loadings did not have a significant effect on the melt crystallization of linear PLA. However, as the clay loading increased in half-branched and fully branched PLA's the reduced molecular mobility started to hinder the crystallization started to be hindered due to the reduced molecular mobility. This threshold occurred at lower clay loadings in fully branched PLA as the mobility started to be limited earlier. On the other hand, clay could improve even the linear PLA's crystallinity during isothermal treatments. On the other hand, branched PLA's processing significantly improved crystallinity due to the completion of chain-branching reactions during the processing. The effects of chain branching and nanoclay on PLA's isothermal melting crystallization kinetics at different temperatures were also studied using Avrami analysis.

This article compares the rheological, thermal, and foaming behaviors of various polylactide (PLA) grades supplied by NatureWorks and their compounds with three different fillers. The results depicted that linear PLAs with various D-content had similar viscoelastic behavior whereas branching and addition of additives improved PLA's complex viscosity and its elastic behavior. Strain hardening behavior was also observed only in PLA with branched structures. Increased complex viscosity due to the induced crystallization was also expedited in PLAs with lower D-content. Addition of chain extender and additives also expedited the crystallization rate and hence expedited the shear viscosity increase. Among the additives, micro-sized talc enhanced PLA's crystallization rate more effectively than the nano-sized additives due to its more dominant role on crystal growth than crystal nucleation that exist in PLAs with nanoparticles. Foam uniformity was however enhanced more significantly in PLAs with nanoparticles.

Additive manufacturing is the process of generating the 3D model as a layer by layer formation using modeling software. Fused deposition modeling 3D printer uses an ABS (acrylonitrile butadiene styrene) and PLA (poly lactic acid) material for printing. In this experiment, analysis of ISO standard nut & bolt is proposed. Nut and bolt can be assembled in plates to create a double cover single bolted butt joint. ANSYS mechanical finite element software is used for simulation of double cover single bolted butt joint and bolts to analyze the mechanical behavior such as equivalent stress, total deformation and maximum principal stress. Comparative analysis of bolts designed with ABS and PLA material is carried out and the respective properties are calculated.

Both within China and globally, a veritable chorus has emerged to greet the imminent arrival of China as a soft power giant poised to remake the world in its own image. If we regard soft power as an extension of the concept of hegemony to the realm of international relations, and as such, necessarily derivative of hard power, it is safe to say that there is a significant gap between China’s economic and military clout and its cultural sway. This is most acutely manifested in divergent perceptions of the People’s Liberation Army (PLA) domestically and abroad. In international media, reporting on the PLA is invariably framed by concerns about security and skepticism about China’s “peaceful rise.” Domestically, however, the PLA has always been instrumental not only to the Party’s grip on power but also to its political hegemony and legitimacy, or its regime of charismatic power. A recent hit television serial, Soldiers Sortie (Shibing tuji, 2007), can help us reevaluate the PLA’s special place in the dialectics of hard and soft power.

In this chapter, I try to make sense of the appeal of this all-male cast soap opera about scores of servicemen training hard, bonding hard, and never thinking of women. I seek to bring together the usually separate questions of domestic hegemony and international influence. The fact that a huge hit like Soldiers Sortie is unlikely to be marketable to foreign audiences (other than military analysts) raises the following questions: Can soft power be assessed merely on the basis of the outward image projected by a country and apart from its living culture? Can “the military-industrial-entertainment complex” of which the PLA is an indispensable part cross borders and conquer hearts and minds without Orientalizing itself? I argue that we need to know what turns on the Chinese before we can expound on how China will turn on the world. To do so, we need to come to terms with a collective self-image that is increasingly the contingent product of negotiations among an overweening state, a wired and vocal population, and a mass media tacking between official mandates and market imperatives.

Por  diferentes  razões  culturais,  sociais,  e  políticas,  a  maioria  dos  professores  de  português  como  língua  adicional  (pla)  na  Colômbia  são  falantes  nativos  sem  formação específica na área de línguas. Nesse contexto, esta pesquisa se pergunta pelas  trajetórias  profissionais  desses  professores  falantes  nativos.  Com  o  objetivo  de  (re)conhecer  seus  processos  de  formação,  entrevistamos  a  vinte  e  cinco  professores  de pla em seis cidades colombianas. Com o uso da metodologia qualitativa de teoria fundamentada, encontramos a categoria de análise: “debute profissional e formativo” que  explica  como  esse  grupo  se  identifica  com  a  docência.  Concluímos  que  os  professores se identificam com as aulas de pla na Colômbia por se reencontrarem com a língua e a cultura brasileira. Mesmo assim, os entrevistados afirmam sentir necessidades específicas de formação docente. Dessa forma, constatamos a extrema necessidade de cursos de graduação e/ou licenciatura orientados para a formação desse profissional na Colômbia.

Now a day, the 3D printing is an increasingly commercially used technology. A crucial section of 3D printing is for providing the printer with printable content if possible, which is achieved by using reels of plastic filament, the most common is PLA, but it is the final product which is sold separately. For this situation, the other option arises that plastic material can be recycled and reused through bottles which are disposable which were discarded in order to be used as printable material. 3D Printing Technology is also defined as rapid prototyping, where a 3-dimensional structure is formed by laying the specific material layers. Three phases such as design, printing & finishing are included here in this process. They use any CAD software in the first step to create 3d design. Use this template to build an object in the 2nd stage 3D printer. And the finished item of the third step is extracted from the printer. This technology saves time and money. This avoids material waste. It is very useful to give the demo of any product in industries.

— Upto date, many experiments have been carried out successfully in producing and using essential oil-treated biodegradable polylactid acid (PLA), but the examinations revealed. That essential oils, theoretically consisting the same composition, (like cinnamonoil, majoram oil, orclaryoil) crystallize differently in the PLA base, weakening its mechanical, optical, and thermal properties. The aim of the experiment is to define the exact components with a Gas-Chromatography instrument with MS-detector. It has been found that among the compounds detected in different cinnamon oil samples, there are indeed other potentially harmful components, such as serpentines, alcoholic derivatives, mineral oils and phthalic acid esters, which have caused the condition to deteriorate. Keywords— biopolymer, essential oils, GC-MS, phtalic acid esters, PLA.

Despite the small difference in the steric hindrance of the substitutes of the asymmetric carbon of the lactic acid, a way for the desymmetrization of the racemic mixture was discovered. Two possibilities have arisen: the synthesis and further separation of diastereoisomers with the (S)-2-methyl-1-butanol as chiral auxiliary and the kinetic discrimination during the esterification with the (R)-(-)-Myrtenol.