Rapid Prototyping

A process for interconnecting a three-dimensional pattern of self-propagating polymer waveguides was used to form micro-truss structures with two new unit cell architectures. The structures were formed using a two-dimensional mask with a hexagonal pattern of apertures. Distinct unit cell architectures were possible by exposing the mask to a different number of incident UV exposure beams, which are used to form the waveguides. One unit cell design featured three intersecting waveguides per node, resulting in a structure with threefold symmetry. The second unit cell design had six-fold symmetry and was characterized by primary nodes with six intersecting waveguides and secondary nodes with two intersecting waveguides. Compression loading experiments were conducted on micro-truss samples with comparable relative density values (q/q s = 6.5%), but different unit cell architectures. The addition of secondary nodes in the structures based on the second design led to an increase in compressive modulus of up to 70% and an average increase in peak strength of 42%. The increase in compressive strength and modulus was attributed to a reduction in the truss-member slenderness ratio achieved through increased waveguide connectivity.

When prototyping the requirement specifications of a large and complex system, it is very dificult to express them in a single model containing all the features. It is often disastrous i f the requirement specifications are prototyped in a single level or single window of a single model. Hence multimodel-based hiemrchical requirement specifications are desirable in order to fully specify large and complex systems. But multimodel-based hierarchical requirement specifications tools are then confronted with verification problems for inter-model consistency and syntactic correctness. W e introduce a predefined graphical structural syntax checker called Model Hierarchy Definition (MHD) which provides interactive hierarchy syntax checking during modeling the structured requirement specijications and predefined lowest level graphical formalisms called Model Hierarchy Model (MHM), defining the meta rules, the graphical diagramming entity and the hierarchical relationship for MHD embedding in the prototyping models. Having MHD and the MHM in the prototyping environment, one obtains higher quality structured requirement specifications when building hierarchical multimodel-based prototypes for complex system analysis, and greatly reduces the prototyping time and costs.

This paper presents state-of-the-art micro and nano-fabrication techniques for biodegradable polymers. Replication molding, using a rigid or elastic master, can pattern structures on a polymer surface in a submicron resolution at a low cost. Layer-by-layer rapid prototyping methods are promising in producing controlled release units with complicated geometries, release mechanisms and the ability to control microstructure and composition. Special attention is paid to the fast, flexible, and non-invasive laser fabrication techniques that have great potential in the fabrication of biodegradable polymer drug delivery devices in both a laboratory and industry scale.

The COVID-19 pandemic has caused a surge of demand for medical supplies and spare parts, which has put pressure on the manufacturing sector. As a result, 3D printing communities and companies are currently operating to ease the breakdown in the medical supply chain. If no parts are available, 3D printing can potentially be used to produce time-critical parts on demand such as nasal swabs, face shields, respirators, and spares for ventilators. A structured search using online sources and feedback from key experts in the 3D printing area was applied to highlight critical issues and to suggest potential solutions. The prescribed outcomes were estimated in terms of cost and productivity at a small and large scale. This study analyzes the number and costs of parts that can be manufactured with a single machine within 24 h. It extrapolates this potential with the number of identical 3D printers in the world to estimate the global potential that can help practitioners, frontline workers, a...

Fidelity is one of the most important parameters to consider when dealing with prototypes, which affect the related costs and performances. Current literature contributions often rely on generic definitions of Fidelity based on the concept of closeness. However, the review performed in this paper revealed that Fidelity is a more complex concept, which considers (at least) eight main dimensions, mutually interrelated, and potentially characterized by many other potential sub-dimensions. The identified set has been applied to an industrial case study were a real engineering prototype has been assessed in terms of Fidelity. In particular, the case study application shows how the different dimensions can be interrelated each other. Furthermore, some important research hints have been highlighted in this paper, where the identified set of Fidelity dimensions paves the way for the related future activities.

Background: Solid plastic replicas of anatomical structures obtained by stereolithography from computed tomographic images and magnetic resonance imaging are being used as complementary tools for diagnostic purposes and therapy planning for diverse pathologies. Case Descriptions: Case 1-The spine mold of a 62-year-old man with neurologic compromise secondary to degenerative cervical disease was used to study the pathologic features of his spine and to plan and simulate the approach to remove osteophytes before surgery. Also, by examining the replica of his spine, the unconvinced patient was able to understand the nature of his pathology and realize that his neurologic symptoms would disappear only through surgery, as they did. Case 2-A 27-year-old woman had uncontrolled back and leg pain possibly related to anxiety and depression. She had undergone one unsuccessful lumbo-sacral surgery and was now obsessed with the thought that her second surgery, performed by us, likewise had failed, even though her magnetic resonance images proved otherwise. It was not until she held a replica of her repaired spine in her hands that she was able to understand that her pain was unfounded. Once she was able to relax, her chronic pain and anxiety disappeared within a month, using the same antidepressive treatment that formerly had been ineffective. Conclusions: Spine replicas are useful devices for diagnosis, planning, and simulating surgery, and they enable patients to understand the nature of their pathologies and the surgical procedures at hand.

Conventional heat exchangers are mainly constructed of metal alloys. The manufacturing process of metal alloys usually requires assembling and joining techniques such as welding and diffusion bonding. In addition, the structures are limited to simple shapes due to the restrictions of the fabrication methods. This research focused on the manufacturing of compact heat exchangers made of high thermal-conductivity ceramic material, rather than on the performance of the devices. To achieve a high surface-volume ratio in heat exchangers, a strategy was adopted that fabricates miniaturized devices with a high shape complexity.

Direct Metal Laser Re-Melting is a variant of the Selective Laser Sintering process, a Rapid Prototyping (RP) technology. This tool-less manufacturing technology has the potential of producing complex, high quality components from single-phase metal powders in short time scales. This is made possible by the production of consecutive two-dimensional layers. Unfortunately, finished components manufactured by this technique have their integrity

This paper discusses the informational requirements of rapid prototyping and layered manufacturing (RPLM). The study is motivated by the recent decision to embark on the development of a new Application Protocol for the international standard ISO 10303, speci®cally to handle layered manufacturing information.

In this paper an analytical dimensional performance evaluation and comparison is illustrated, done on benchmarks manufactured using two different 3D FDM printers: an industrial system, and an open-source one (a modified Fab@Home Model 1 printer). Using a factorial analysis design of experiment (DOE), optimum process parameters were found to improve dimensional accuracy on rectangular test specimens, minimizing changes in length, width and height. Fab@Home printer demonstrated to be a good platform, simple, flexible and inexpensive. Video abstract To view the video inline, enable JavaScript on your browser. However, you can download and view the video by clicking on the icon below Help with MP4 files Options Download video (2234 K)

This paper describes an ongoing effort to develop computer-simulated instrumentation for the UMTRI Driver Interface Research Simulator. The speedometer, tachometer, engine and fuel gauges, along with warning lights are back projected onto a screen in front of the driver. The image is generated by a Macintosh running LabVIEW. Simulated instrumentation (instead of a production cluster) was provided so that new display designs can be rapidly generated and tested.

This study shows the effects of aging on epoxy-based rapid tooling materials. Two epoxy-acrylate resins used for stereolithography and one aluminum powder-filled epoxy used for the high speed machining of plastic injection molds were selected to investigate their aging behavior in different environments. Four different conditions, each characterized by a specific relative humidity, were used to perform a seven week long aging study. Temperature was kept constant at 30°C. Both stereolithographic resins showed a drop in mechanical properties and in their glass transition temperatures in wet environments, whereas aging time showed little influence on these properties. Moisture uptake is mainly responsible for that drop and coefficients of water diffusion were determined. On the other hand, the aluminum powder-filled epoxy showed little humidity-dependent drop in mechanical properties and in its glass transition temperature during aging. This result correlates well with the very low moisture absorption of this material.

1We describe an approach and an environment for setting up Wizard of Oz experiments to test multimodal interaction (through mobile devices) for multimedia content delivery. This is based on a metamodel and a reference client-server architecture, whose implementation is discussed. The approach allows progressive refinement of the Wizard of Oz environment into a deployed application, through the use of a single metamodel, to be progressively specialized, and a service-oriented approach which allows the substitution ...

In this paper we introduce a vision for a new type of domestic appliance, a soft-appliance, constructed from aggregations of elementary network services. The vision is based on the possibility of 'deconstructing', logically, conventional home appliances such as TVs into their elemental functions which may then be combined in novel ways with other deconstructed services to generate soft-appliance of a person's own choosing. Additionally our aim is to describe the computer science challenges involved in fulfilling this vision. An essential component of this vision is a concept called a MAp (metaappliance/application); a semantic data template that describes the soft or virtual-appliance that can be instantiated by manufacturers and end-users in a way that redefines the nature of an appliance and which can be created, owned and traded. We also present a socio-technical framework to motivate the discussion of this research agenda, especially the use of the agent technology that would be needed to realise this vision.

In this paper, we present a new generation of active tactile modules (i.e., HEX-O-SKIN), which are developed in order to approach multimodal whole-body-touch sensation for humanoid robots. To better perform like humans, humanoid robots need the variety of different sensory modalities in order to interact with their environment. This calls for certain robustness and fault tolerance as well as an intelligent solution to connect the different sensory modalities to the robot. Each HEX-O-SKIN is a small hexagonal printed circuit board equipped with multiple discrete sensors for temperature, acceleration, and proximity. With these sensors, we emulate the human sense of temperature, vibration, and light touch. Off-the-shelf sensors were utilized to speed up our development cycle; however, in general, we can easily extend our design with new discrete sensors, thereby making it flexible for further exploration. A local controller on each HEX-O-SKIN preprocesses the sensor signals and actively routes data through a network of modules toward the closest PC connection. Local processing decreases the necessary network and high-level processing bandwidth, while a local analog-to-digital conversion and digital-data transfers are less sensitive to electromagnetic interference. With an active data-routing scheme, it is also possible to reroute the data around broken connections-yielding robustness throughout the global structure while minimizing wirings. To support our approach, multiple HEX-O-SKIN are embedded into a rapid-prototyped elastomer skin material and redundantly connected to neighboring modules by just four ports. The wiring complexity is shifted to each HEX-O-SKIN such that a power and data connection between two modules is reduced to four noncrossing wires. Thus, only a very simple robot-specific base frame is needed to support and wire the HEX-O-SKIN to a robot. The potential of our multimodal sensor modules is demonstrated experimentally on a robot platform.

Purpose - The goal of this study is to evaluate the energy consumed to fabricate nylon parts using selective laser sintering (SLS) and to compare it with the energy consumed for injection molding (IM) the same parts.

Design/methodology/approach - Estimates of energy consumption include the energy consumed for nylon material refinement, adjusted for SLS and IM process yields. Estimates also include the energy consumed by the SLS and IM equipment for part fabrication and the energy consumed to machine the injection mold and refine the metal feedstock required to fabricate it. A representative part is used to size the injection mold and to quantify throughput for the SLS machine per build.

Findings - Although SLS uses significantly more energy than IM during part fabrication, this energy consumption is partially offset by the energy consumption associated with production of the injection mold. As a result, the energy consumed per part for IM decreases with the number of parts fabricated while the energy consumed per part for SLS remains relatively constant as long as builds are packed efficiently. The crossover production volume, at which IM and SLS consume equivalent amounts of energy per part, ranges from 50 to 300 representative parts, depending on the choice of mold plate material.

Research limitations/implications - The study is limited to material refinement and part fabrication and does not consider other aspects of the life cycle, such as waste disposal, distributed manufacturing, transportation, recycling or use. Also, the crossover volumes are specific to the representative part and are expected to vary with part geometry.

Originality/value - The results of this comparative study of SLS and IM energy consumption indicate that manufacturers can save energy using SLS for parts with small production volumes. The comparatively large amounts of nylon material waste and energy consumption during fabrication make it inefficient, from an energy perspective, to use SLS for higher production volumes. The crossover production volume depends on the geometry of the part and the choice of material for the mold.

Time needed to set-up and send new products to the market is a crucial factor for success, so one important rule is to develop your product as quickly as you can. In the electronics world the systems normally contain some parts in HW and others in SW being the HW/SW partition a crucial issue in the cost-performance trade-off. A bad choice usually requires the redesign or remaps of some parts the system with the consequent waste of time and money.

Rapid prototyping (RP) is a common name for several techniques, which read in data from computer-aided design (CAD) drawings and manufacture automatically threedimensional objects layer-by-layer according to the virtual design. The utilization of RP in tissue engineering enables the production of three-dimensional scaffolds with complex geometries and very fine structures. Adding micro-and nanometer details into the scaffolds improves the mechanical properties of the scaffold and ensures better cell adhesion to the scaffold surface. Thus, tissue engineering constructs can be customized according to the data acquired from the medical scans to match the each patient's individual needs. In addition RP enables the control of the scaffold porosity making it possible to fabricate applications with desired structural integrity. Unfortunately, every RP process has its own unique disadvantages in building tissue engineering scaffolds.

Most rapid prototyping (RP) additive techniques are expensive and suffer from a lack of efficiency when massive products are to be manufactured. The authors propose to reduce the density of rapid prototyped parts, finding alternative building styles. Topologically optimized parts have been created with internal geometry, using a narrow-waisted structure that avoids the need for building supports. In order to characterise and study the behaviour of the obtained low density parts, an experimental plan has been designed and executed. The approach has been tested using a fused deposition modelling (FDM) machine, but it is of a general nature and can be applied to other layered manufacturing (LM) technologies that use supports, dealing with slow building of massive parts.

Rapid prototyping RP technology has been developing very fast in the last 10 years. Some ideas concerning this technology are presented in the paper for predicting the evolution in the future. Shaping science is proposed to research for the improvement of RP process and generation of new processes. Issues including product development tool, direct metal part manufacturing, rapid tooling and RP machine design are discussed. Extension of its application in more areas will be beneficial for the advancement of RP. q

The purpose of ARINC 661 specification [1] is to define interfaces to a Cockpit Display System (CDS) used in any types of aircraft installations. ARINC 661 provides precise information for communication protocol between application (called User Applications) and user interface components (called widgets) as well as precise information about the widgets themselves. However, in ARINC 661, no information is given about the behaviour of these widgets and about the behaviour of an application made up of a set of such widgets. This paper presents the results of the application of a formal description technique to the various elements of ARINC 661 specification within an industrial project. This formal description technique called Interactive Cooperative Objects defines in a precise and non-ambiguous way all the elements of ARINC 661 specification. The application of the formal description techniques is shown on an interactive application called MPIA (Multi Purpose Interactive Application). Within this application, we present how ICO are used for describing interactive widgets, User Applications and User Interface servers (in charge of interaction techniques). The emphasis is put on the model-based management of the feel of the applications allowing rapid prototyping of the external presentation and the interaction techniques. Lastly, we present the CASE (Computer Aided Software Engineering) tool supporting the formal description technique and its new extensions in order to deal with large scale applications as the ones targeted at by ARINC 661 specification.

Solvent-based extrusion freeforming is capable of building complex ceramic 3D structures and can be used in the fabrication of hard and soft tissue scaffolds, photonic crystals for millimetre wave, ordered ceramic preforms for metal matrix composites, precise molten metal filters and potentially for terahertz bandgap metamaterials. This is a powder-based rapid prototyping process, the principle of which is the realization of liquid to solid transition through solvent evaporation in the presence of a binder. We describe the characteristics of pastes prepared from different powders, notably the rheological properties at different solvent fractions and illustrate some of the structures fabricated by this technique.

Purpose – The purpose of this paper is to present a custom-built tribometer that mimics the wear of additive manufactured fixtures used in inspection of sheet metal components. Design/methodology/approach – Referring to the inspection of sheet metal parts, the fixture undergoes sliding wear during loading and unloading phases of the quality control operation. A new wear test is proposed to mimic the actual wearing conditions of the fixtures because the standards are deemed insufficient. In the tribometer, a cylindrical Alumide cantilever beam is made to slide back and forth inside a slightly bigger hole cut into a nickel-plated steel sheet. The sheet is spring loaded such that it applies a force on the specimen. The wear on the beam is measured after every 500 cycles of the beam motion. Findings – Results of some first test trials are reported to evaluate the durability of Alumide fixtures fabricated by selective laser sintering. The results are also compared to those obtained for a...

Analysis of complex imaging tasks requires a phantom that simulates the patient anatomy. We have developed a technique to fabricate 3D physical anthropomorphic breast phantoms for image quality assessment of 2D and 3D breast x-ray imaging systems. The phantom design is based on an existing computer model that can generate breast voxel phantoms of varying size, shape, glandularity, and internal composition. The physical phantom is produced in two steps. First, the computer model of the glandular tissue, skin and Coopers' ligaments is separated into sections. These sections are fabricated by high-resolution rapid prototype printing using a single tissue equivalent material. The adipose tissue regions in the sections are filled using an epoxy-based resin combined with phenolic microspheres. The phantom sections are then stacked. The phantom is provided with an extra section modified to include iodine-enhanced masses. We fabricated a prototype phantom corresponding to a 450 ml breast with 45% dense tissue deformed to represent a 5 cm compressed thickness. The rapid prototype and epoxy based resin phantom materials attenuate x rays similar to 50% glandular tissue and 100% adipose tissue, respectively. The iodinated masses are between 4.0 and 9.6 mm thick and contain 2.5 mg/ml and 5 mg/ml iodine. Digital mammography and digital breast tomosynthesis images of the phantom are qualitatively similar in appearance to clinical images. In summary, a method to fabricate a 3D physical anthropomorphic breast phantom has been developed with known ground truth in the form of a companion voxel phantom. This combined system of physical and computational phantoms allows for both qualitative and quantitative image quality assessment.

________ SynthBuilder is a user-extensible,object-oriented , NEXTSTEP Music Kit application for interactive real-time design and performance of synthesizer patches, especially physical models [Smith 1987]. Patches are represented by networks consisting of digital signal processing elements called unit generators and MIDI event elements called note filters and note generators. As an example of the kinds of patches developed, a six-string

Although mobile, tablet, large display, and tabletop computers increasingly present opportunities for using pen, finger, and wand gestures in user interfaces, implementing gesture recognition largely has been the privilege of pattern matching experts, not user interface prototypers. Although some user interface libraries and toolkits offer gesture recognizers, such infrastructure is often unavailable in design-oriented environments like Flash, scripting environments like JavaScript, or brand new off-desktop prototyping environments. To enable novice programmers to incorporate gestures into their UI prototypes, we present a "$1 recognizer" that is easy, cheap, and usable almost anywhere in about 100 lines of code. In a study comparing our $1 recognizer, Dynamic Time Warping, and the Rubine classifier on user-supplied gestures, we found that $1 obtains over 97% accuracy with only 1 loaded template and 99% accuracy with 3+ loaded templates. These results were nearly identical to DTW and superior to Rubine. In addition, we found that medium-speed gestures, in which users balanced speed and accuracy, were recognized better than slow or fast gestures for all three recognizers. We also discuss the effect that the number of templates or training examples has on recognition, the score falloff along recognizers' N-best lists, and results for individual gestures. We include detailed pseudocode of the $1 recognizer to aid development, inspection, extension, and testing. Figure 1. Unistroke gestures useful for making selections, executing commands, or entering symbols. This set of 16 was used in our study of $1, DTW [18,28], and Rubine [23].

IoT and embedded electronics is getting popular due to its versatile applications in various fields for domestic, commercial and industrial usage. However electronics or electrical systems that are primarily built using electronics, needs enclosures to protect it from the environment as well as for maintaining its privacy concerns. 3D printers are valuable to rapidly prototype/fabricate/build enclosures for custom applications. The steps, involved in rapid prototyping using 3D printers start from understanding the specification and measurement requirements e.g. colour, look, dimensions, and tolerances. Followed by designing the model using a specialized computer-aided designing (CAD) software application. After modelling and designing in CAD, the file is converted and saved with a different file extension called the Standard Tessellation Language (.stl). Design files with the .stl extension can be fed to the most widely used 3D printers on the market today. Finally, printer parameters must be optimally set to print insert jobs automatically with minimal human intervention. The purpose of this document is to demonstrate a project and document all steps related to rapid prototyping of packages/enclosures for custom IoT-enabled sensors. It also summarizes the experience and strengths and weaknesses of using this technology in general.

Over the past four years there has been a tremendous resurgence of "public" interest inside and outside of IBM in APL and especially APL2 as a result of 1. an awareness of the importance of for technical computing, rapid prototyping, array algorithms for parallel computing, and advanced decision support 2. state-of-the-art work being done with APL in such diverse areas as medical imaging, finance, manufacturing scheduling, spot market oil buying and selling, computer design, chip design, mathematics, knowledge based systems statistics, etc. 3. IBM establishing APL2 as its strategic interactive language and making it a key player in its technical computing strategy Due to this renewed interest, I have compiled a list of some APL-related articles on Modeling and on Knowledge-Based Expert Systems .(KBES).

Selective laser sintering (SLS) Rapid prototyping Finite element Polycarbonate Process modelling a b s t r a c t A transient three-dimensional finite element model is developed to simulate the phase transformation during the selective laser sintering process; taking into account the thermal and sintering phenomena involved in this process. A bi-level structure integration procedure is chosen, in which the temperature dependent thermal conductivity, specific heat, and density are integrated at the outer level then used as material constants for the integration of the heat equation in the inner level. Results for temperature and density distribution, using a polycarbonate powder, are presented and discussed.

In our paper we describe the development and evaluation of a promising prototyping tool, which is intended to facilitate the design of prototypes for inexperienced practitioners in educational and corporate projects. Based on observations we assumed that inexperienced practitioners rather unintentionally prototype solutions that may not be necessarily suitable with regard to their implicit needs. We conclude that different prototypes may be more or less suitable within innovation processes, depending on different purposes. The goal was to develop a concrete tool that may inspire those practitioners to develop prototypes more efficiently, by creating a better understanding of different application scenarios and an overview of prototypes that may be more suitable within these different scenarios that occur along innovation processes. We thus aimed at combining insights from our own empirical research on prototyping and previous insights from academy research. We designed a set of cards representing different prototypes and furthermore arranged these cards differently in order to develop a framework that provides a meaningful guidance for our target users. After several iterations, we developed a so-called prototyping canvas, which will be introduced in this paper.

In recent years, Rapid Prototyping Technology (RPT) has been implemented in many spheres of industry, particularly in the area of product development. Existing processes provide the capability to rapidly produce a tangible solid part, directly from three dimensional Computer-Aided Design (CAD) data, from a range of materials such as photocurable resin, powders and paper. In many situations, the desired end product of a developmental cycle is a metallic object that is dimensionally stable and of high accuracy, whether it is a component or a tool. However, in most cases, models built in the acrylic based resin in the StereoLithography process has not yielded the desired quality and this has led to a shift in the use of this resin to some more expensive ones that have longer build time. A unique experimental investigation has been carried out to statistically determine the optimum build parameters to be used with the use of Taguchi Method, as to improve the SLA product quality. Two new hatch styles have been developed in this study which has resulted in the overall improvement of the part surface finish.

This paper discusses recent results toward the design, rapid prototyping and testing of a ducted microquadcopter. Mobility and convenience objectives of this work dictate that the quadcopter must fit into a pocket, be capable of shooting high-definition videos and pictures,  be  controllable through a smartphone application,  have  a rotor diameter of 7cm and weigh approximately 300 g. Previous designs have rotor dimensions of 25 cm or more as well as airframe width and length of 75 cm and above. Aerodynamically, the ducted fan design is analyzed through Momentum Theory and Blade Element Momentum Theory (BEMT) to determine its contribution toward improved  performance in hover, axial climb, axial descent and forward flight. The ducted fan design can be optimized for lower power consumption of up to 30% or smaller diameter than an open rotor and improves hover performance most significantly. Individual components, including the upper ducted and lower airframe were fabricated using composite layup methods. Microrotors as well as ducted fan molds  were designed and built through three-dimensional (3D) Printing methods, including the Fused Deposit Modeling (FDM) and the PolyJet (PJ) method. Careful attention was taken to patch the duct lips with composites and sanding them to ensure smoothness.  It was found that microrotors have to have at least a 4% thickness-to-chord ratio in order to be structurally sound.  For the FDM method, the microrotors have to be printed with the blade plane perpendicular to the print bed and the
oriented such that the blades have the strongest structural layout possible. For four and two blades, the best configurations are having the blades at having the blades at 60° and 0° (horizontal) to the print bed respectively. The PJ method, is capable of printing highly accurate microrotors flat on the print bed. However, they are less stiff and tend to flap more and structurally deform under exposure to ultraviolet (UV) and heat sources, hence making them more suitable for short term usage. Test results indicate that the FDM rotors produce more thrust than PJ rotors and have a lower torque-to-thrust ratio due to the fact that PJ rotors are less stiff. This in turn leads to excessive flapping and more susceptibility to flutter, which requires thicker blades at the expense of higher profile drag.
Likewise, PJ rotors can be designed for higher thrust and lower torque-to-thrust ratio by incorporating constant chord blades at lower pitch angles, yet maintaining the same diameter and solidity as their variable chord counterparts.

Resumo: A democratização dos processos de Manufatura Aditiva por extrusão, motivada pelo desenvolvimento das impressoras 3D de código aberto, permitiu o uso dessas tecnologias em ambientes domésticos e de negócios, além de ser desejável no cenário de pesquisas, garantindo maior flexibilidade e possibilidades de adaptações. Dentre os principais materiais utilizados neste conceito de máquinas estão os filamentos de poli(ácido lático) (PLA), disponíveis em uma vasta gama de cores e fornecedores. Filamentos de PLA são muito populares, principalmente entre entusiastas da impressão 3D, uma vez que apresentam maior facilidade de impressão quando comparados a outros materiais disponíveis. Entretanto, pouco se conhece a respeito das propriedades destes materiais, abrindo uma lacuna no cenário das pesquisas acadêmicas, onde o conhecimento técnico sobre a matéria prima é de grande importância. Neste sentido, o presente artigo buscou avaliar diferentes filamentos de PLA com variação na coloração, e comercialmente ditos naturais. Para a caracterização dos filamentos foram realizados inicialmente três técnicas: calorimetria diferencial de varredura (DSC), análise termogravimétrica (TGA), e espectroscopia no infravermelho por transformada de Fourier (FTIR); os dois primeiros para se obter as temperaturas de fusão, transição vítrea, e de degradação, e o terceiro para identificar os principais elementos da composição química dos materiais. Uma quarta análise foi realizada, entretanto com apenas dois filamentos — um pigmentado e um natural —, para medir a densidade dos materiais e possibilitar comparações com valores disponibilizados na literatura. Os resultados encontrados mostram que, em relação à temperatura de transição vítrea, materiais coloridos e naturais apresentaram valores muito próximos; comportamento semelhante também foi observado em relação à temperatura de degradação. A análise da temperatura de fusão revelou dois grupos distintos: filamentos de PLA semicristalinos com variações na temperatura de fusão, e filamentos amorfos. Quanto à composição química, não foram constatadas diferenças significativas, mesmo em amostras com e sem pigmentos. Por fim, na medição da densidade também foram encontrados valores similares entre as amostras analisadas, e próximos aos valores descritos na literatura

Direct Metal Deposition (DMD) builds metallic parts layer by layer directly from the CAD data. The process has been widely used in manufacturing, part repairing/coating and metallic rapid prototyping.
However, success of this technology depends upon the final quality of the components produced, which in fact strongly dependent upon various parameters such as laser power, beam diameter, scanning speed, powder mass flow rate, etc. this paper presents a review on the DMD process, its parameters and influence of the parameters on final characteristics of the components.

Co-Founder, Autosustaintive 3D printing and prototyping services, Vishrambagh, Sangli, India 3 Technical Consultant, Autosustaintive 3D printing and prototyping services, Vishrambagh, Sangli, India 4 ABSTRACT:-3D printing is an additive manufacturing process in which the entire part of a product is constructed using layer by layer deposition of materials that based on plastic and its derivatives. There are various processes of 3D printing namely fused deposition modelling (FDM), selective laser sintering (SLS), stereolithography (SLA), digital light processing (DLP), and multi jet fusion (MJF) to name a few. Each process has its unique characteristics and applications but the fused deposition modelling process is widely used due to its simplicity. As additive manufacturing processes becoming more common coupled with rapid technological advancement in the manufacturing sector, we may see the decentralised manufacturing network in the near future. The prices of 3D printers vary depending of several factors related to the type of printing material used, and the precision and quality requirements. This paper discusses a study conducted on using low cost 3d printer for rapid prototyping a commercially ready product. It also summarises the experiences, advantages and disadvantages of the study.

Stereolithography process limits wider applications due to low dimensional accuracy comparing with CNC process. Hence, to improve accuracy and reduce part distortion, understanding the physics involved in the relationship between the setup input parameters and the part dimensional accuracy is prerequisite. In this paper, a model is proposed to find and optimize important parameters to achieve higher accuracy and also predict dimensional accuracy using various parameters values. For this purpose, the result of a previous study is used, where it is found that in stereolithography process these factors in order of importance with respect to dimensional accuracy are: layer thickness, hatch style, hatch spacing, hatch fill cure depth and hatch overcure. Moreover, in this research the proposed neural network model is able to predict dimensional accuracy with 6% error.

Additive manufacturing colloquially known as 3 dimensional printing or 3D printing has evolved to a futuristic state
since its emergence around 1987. Industries have imbibe the idea and technology and laid down a low cost production path for
the future.

Optimization of radio-frequency identification (RFID) tags often requires several iterations of antenna design/fabrication/testing to meet cost and performance targets. The use of a rapid prototyping approach for antenna development would allow the designer an inexpensive and fast route to the refinement process. In this study, the performance of a commercial-off-the-shelf ultrahigh frequency (UHF) etched copper antenna was compared to printed silver antennas prepared by the following three direct-write techniques: maskless mesoscale materials deposition; matrix-assisted pulsed laser evaporation direct-write; and, collimated aerosol beam direct-write. The morphologies of the antennas were analyzed using contact and optical profilers with sheet resistance also being measured. Operational characteristics were determined by mounting silicon integrated circuits (IC) to the four different types of antennas. The performance of tags that utilized direct-write silver antennas was comparable to the copper-based commercial tag. To our knowledge, this is the first demonstration where some of the direct-write rapid prototyping attributes (e.g., slight overspray, overlap of written lines, overall thickness less than 500 nm) are shown to not seriously impede RFID tag performance. These results demonstrate the utility of direct-write for rapid prototyping studies for UHF RFID antennas.

This overview will focus on the direct fabrication of metal components by using laser-forming techniques in a layer-by-layer fashion. The main driving force of rapid prototyping (RP) or layer manufacturing techniques changed from fabrication of prototypes to rapid tooling (RT) and rapid manufacturing (RM). Nowadays, the direct fabrication of functional or structural end-use products made by layer manufacturing methods, i.e. RM, is the main trend. The present paper reports on the various research efforts deployed in the past decade or so towards the manufacture of metal components by different laser processing methods (e.g. selective laser sintering, selective laser melting and 3-D laser cladding) and different commercial machines (e.g. Sinterstation, EOSINT, TrumaForm, MCP, LUMEX 25, Lasform). The materials and applications suitable to RM of metal parts by these techniques are also discussed. r