The vision of the Department of Mechanical Engineering, National Institute of Technology Silchar is as follows: To envisage an ambience of excellence, inspiring value based education, research and development in Mechanical. History Terminology and methods. Early Additive Manufacturing (or AM) equipment and materials were developed in the 1980s. In 1981, Hideo Kodama of Nagoya Municipal Industrial Research Institute invented two AM fabricating. Sahani, A.K.; Jain, P.K. Introduction The technology has undergone major changes over the centuries to meet the changing requirement of the society. Nanosilver leached from commercial sock material is quantified and characterized, and its treatment in a wastewater treatment plant is modeled. PHARMACEUTICAL MANUFACTURING HANDBOOK Regulations and Quality SHAYNE COX GAD, PH.D., D.A.B.T. Gad Consulting Services Cary, North Carolina A JOHN WILEY & SONS, INC., PUBLICATION. Bank PO Numerical Ability Sample Paper 1. A clock shows the time as 6 a.m. If the minute hand gains 2 minutes every hour, how many minutes will the clock gain by 9 p.m.? YOJANA April 2015 YOYOJANA April 2015 JANA April 2015 5 M anufacturing industry is of signi. Developing countries like India largely depend on manufacturing industry for. D printing - Wikipedia, the free encyclopedia. D printing, also known as additive manufacturing (AM), refers to processes used to synthesize a three- dimensional object. ![]() More recently, the term is being used in popular vernacular to encompass a wider variety of additive manufacturing techniques. United States and global Technical standards use the official term additive manufacturing for this broader sense. ISO/ASTM5. 29. 00- 1. AM processes within its meaning: Binder Jetting, Directed Energy Deposition, Material Extrusion, Material Jetting, Powder Bed Fusion, Sheet Lamination and Vat Photopolymerization. The application of French inventors were abandoned by the French General Electric Company (now Alcatel- Alsthom) and CILAS (The Laser Consortium). Hull defined the process as a . Hull's contribution is the design of the STL (STereo. Lithography) file format widely accepted by 3. D printing software as well as the digital slicing and infill strategies common to many processes today. The term 3. D printing originally referred to a process employing standard and custom inkjet print heads. The technology used by most 3. D printers to date. At the time, nearly all metal working was produced by casting, fabrication, stamping, and machining; although plenty of automation was applied to those technologies (such as by robot welding and CNC), the idea of a tool or head moving through a 3. D work envelope transforming a mass of raw material into a desired shape layer by layer was associated by most people only with processes that removed metal (rather than adding it), such as CNC milling, CNC EDM, and many others. But AM- type sintering was beginning to challenge that assumption. By the mid 1. 99. Stanford and Carnegie Mellon University, including microcasting. It was during this decade that the term subtractive manufacturing appeared as a retronym for the large family of machining processes with metal removal as their common theme. At this time, the term 3. D printing still referred only to the polymer technologies in most minds, and the term AM was likelier to be used in metalworking and end use part production contexts than among polymer/inkjet/stereolithography enthusiasts. The term subtractive has not replaced the term machining, instead complementing it when a term that covers any removal method is needed. By the early 2. 01. D printing and additive manufacturing evolved senses in which they were alternate umbrella terms for AM technologies, one being used in popular vernacular by consumer - maker communities and the media, and the other used officially by industrial AM end use part producers, AM machine manufacturers, and global technical standards organizations. Both terms reflect the simple fact that the technologies all share the common theme of sequential- layer material addition/joining throughout a 3. D work envelope under automated control.(Other terms that had been used as AM synonyms (although sometimes as hypernyms), included desktop manufacturing, rapid manufacturing, agile tooling . Agile tooling uses a cost effective and high quality method to quickly respond to customer and market needs. It can be used in hydro- forming, stamping, injection molding and other manufacturing processes. As technology matured, several authors had begun to speculate that 3. D printing could aid in sustainable development in the developing world. D printed models created with CAD result in reduced errors and can be corrected before printing, allowing verification in the design of the object before it is printed. D scanning is a process of collecting digital data on the shape and appearance of a real object, creating a digital model based on it. Printing. Most CAD applications produce errors in output STL files. Typical layer thickness is around 1. The particles (3. D dots) are around 5. Additive systems can typically reduce this time to a few hours, although it varies widely depending on the type of machine used and the size and number of models being produced simultaneously. D printers give designers and concept development teams the ability to produce parts and concept models using a desktop size printer. See complexity paradox for more information. Finishing. These techniques are able to print in multiple colors and color combinations simultaneously, and would not necessarily require painting. Some printing techniques require internal supports to be built for overhanging features during construction. These supports must be mechanically removed or dissolved upon completion of the print. All of the commercialized metal 3. D printers involve cutting the metal component off the metal substrate after deposition. A new process for the GMAW 3. D printing allows for substrate surface modifications to remove aluminum. The main differences between processes are in the way layers are deposited to create parts and in the materials that are used. Some methods melt or soften the material to produce the layers, for example. With laminated object manufacturing (LOM), thin layers are cut to shape and joined together (e. Each method has its own advantages and drawbacks, which is why some companies offer a choice of powder and polymer for the material used to build the object. The main considerations in choosing a machine are generally speed, costs of the 3. D printer, of the printed prototype, choice and cost of the materials, and color capabilities. However less expensive printers can be used to make a mold, which is then used to make metal parts. Such principle has been further developed by S. Scott Crump in the late 1. Stratasys. As a result, the price of this technology has dropped by two orders of magnitude since its creation. In fused deposition modeling the model or part is produced by extruding small beads of material which harden immediately to form layers. A thermoplastic filament or metal wire that is wound on a coil is unreeled to supply material to an extrusion nozzle head (3. D printer extruder). The nozzle head heats the material and turns the flow on and off. Typically stepper motors or servo motors are employed to move the extrusion head and adjust the flow. The printer usually has 3 axes of motion. A computer- aided manufacturing (CAM) software package is used to generate the G- Code that is sent to a microcontroller which controls the motors. Extrusion in 3. D printing using material extrusion involves a cold end and a hot end. Various polymers are used, including acrylonitrile butadiene styrene (ABS), polycarbonate (PC), polylactic acid (PLA), high- density polyethylene (HDPE), PC/ABS, polyphenylsulfone (PPSU) and high impact polystyrene (HIPS). In general, the polymer is in the form of a filament fabricated from virgin resins. There are multiple projects in the open- sourced community aimed at processing post- consumer plastic waste into filament. These involve machines used to shred and extrude the plastic material into filament. Additionally, fluoropolymers such as PTFE tubing are used in the process due to the material's ability to withstand high temperatures. This ability is especially useful in transferring filaments. For example, FDM usually cannot produce stalactite- like structures, since they would be unsupported during the build. Otherwise, a thin support must be designed into the structure, which can be broken away during finishing. Fused deposition modeling is also referred to as fused filament fabrication (FFF) by companies who do not hold the original patents like Stratasys does. Binding of granular materials. The technique fuses parts of the layer and then moves upward in the working area, adding another layer of granules and repeating the process until the piece has built up. This process uses the unfused media to support overhangs and thin walls in the part being produced, which reduces the need for temporary auxiliary supports for the piece. A laser is typically used to sinter the media into a solid. Examples include selective laser sintering (SLS), with both metals and polymers (e. PA, PA- GF, Rigid GF, PEEK, PS, Alumide, Carbonmide, elastomers), and direct metal laser sintering (DMLS). Joseph Beaman at the University of Texas at Austin in the mid- 1. EBM manufactures parts by melting metal powder layer by layer with an electron beam in a high vacuum. Unlike metal sintering techniques that operate below melting point, EBM parts are void- free. The printer creates the model one layer at a time by spreading a layer of powder (plaster, or resins) and printing a binder in the cross- section of the part using an inkjet- like process. This is repeated until every layer has been printed. This technology allows the printing of full color prototypes, overhangs, and elastomer parts. The strength of bonded powder prints can be enhanced with wax or thermoset polymer impregnation. Lamination. During the 1. In 2. 00. 5 Mcor Technologies Ltd developed a different process using ordinary sheets of office paper, a tungsten carbide blade to cut the shape, and selective deposition of adhesive and pressure to bond the prototype. This process was a dramatic departure from the . The exposed liquid polymer hardens. Polymerization occurs when photopolymers are exposed to light when photopolymers contain chromophores, otherwise, the addition of molecules that are photosensitive are utilized to react with the solution to begin polymerization. Polymerization of monomers lead to cross- linking, which creates a polymer. Through these covalent bonds, the property of the solution is changed. The process repeats until the model has been built. The liquid polymer is then drained from the vat, leaving the solid model. The Envision. TECPerfactory. Each photopolymer layer is cured with UV light after it is jetted, producing fully cured models that can be handled and used immediately, without post- curing. The gel- like support material, which is designed to support complicated geometries, is removed by hand and water jetting. It is also suitable for elastomers. Ultra- small features can be made with the 3.
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