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44-611: Selective laser sintering (SLS) was developed and patented by Dr. Carl Deckard and academic adviser, Dr. Joe Beaman at the University of Texas at Austin in the mid-1980s, under sponsorship of DARPA . Deckard and Beaman were involved in the resulting start up company Desk Top Manufacturing (DTM) Corp, established to design and build the SLS machines. In 2001, 3D Systems, the biggest competitor to DTM Corp. and SLS technology, acquired DTM Corp.. The most recent patent regarding Deckard's SLS technology

88-425: A pulsed laser . The SLS machine preheats the bulk powder material in the powder bed somewhat below its melting point, to make it easier for the laser to raise the temperature of the selected regions the rest of the way to the melting point. In contrast with SLA and FDM, which most often require special support structures to fabricate overhanging designs, SLS does not need a separate feeder for support material because

132-419: A 3-D digital description of the part (for example from a CAD file or scan data) on the surface of a powder bed. After each cross-section is scanned, the powder bed is lowered by one layer thickness, a new layer of material is applied on top, and the process is repeated until the part is completed. Because finished part density depends on peak laser power, rather than laser duration, a SLS machine typically uses

176-501: A half years, Deckard returned to Austin to work on the Deckard Engine, a four-stroke engine aimed at replacing emission-emitting two-stroke engines in small, hand-held products. The majority of Deckard's work was in the additive manufacturing industry. In 2012, Deckard co-founded Structured Polymers LLC, a company that develops novel polymers for SLS machines. Thermoplastic A thermoplastic , or thermosoftening plastic ,

220-404: A product surface. PVDF is widely used in the chemical industry as piping for aggressive chemicals and high purity liquids. The PVDF material is used in construction, transportation, chemical processes, electricity, batteries, waste water and treatment. Polytetrafluoroethylene (PTFE) is a synthetic fluoropolymer of tetrafluoroethylene is commonly recognized under the brand name Teflon . PTFE

264-517: A professor at UT Austin. After several years of trial-and-error, Deckard's machine was capable of manufacturing real parts. He licensed the technology from UT Austin and co-founded Desk Top Manufacturing (DTM) Corp. in 1987. DTM Corp. specialized in rapid prototyping and manufacturing systems for manufacturers and service bureaus. DTM Corp. was acquired by 3D Systems in 2001 at a $ 45 million valuation. Deckard became an engineering professor at Clemson University after DTM's acquisition. After three and

308-405: A reduction in viscosity and the formation of a concave radial bridge between particles, known as necking, due to the material's response to lower its surface energy. In the case of coated powders, the purpose of the laser is to melt the surface coating which will act as a binder. Solid state sintering is also a contributing factor, albeit with a much reduced influence, and occurs at temperatures below

352-598: A unique resin identification code. Items made from polycarbonate can contain the precursor monomer bisphenol A (BPA). Susceptible to UV light, exposure results in yellowing (degradation is especially visible in headlamps that lost or didn't have proper protective coating). Polyether sulfone (PES) or polysulfone is a class of specially engineered thermoplastics with high thermal, oxidative, and hydrolytic stability, and good resistance to aqueous mineral acids, alkalis, salt solutions, oils and greases. Polyoxymethylene (POM), also known as acetal, polyacetal and polyformaldehyde,

396-421: Is a family of similar materials categorized according to their density and molecular structure. It is also known as poly and is obtained by the addition polymerisation of ethylene. It may be of low density or high density depending upon the process used in its manufacturing. It is resistant to moisture and most of the chemicals. It is flexible at room temperature (and low temperature) and can be heat sealed. Since it

440-1009: Is a synthetic fiber with a very high melting point. It has exceptional thermal and chemical stability and does not readily ignite. It was first discovered by American polymer chemist Carl Shipp Marvel in the pursuit of new materials with superior stability, retention of stiffness, toughness at elevated temperature. Due to its high stability, polybenzimidazole is used to fabricate high-performance protective apparel such as firefighter's gear, astronaut space suits, high temperature protective gloves, welders' apparel and aircraft wall fabrics. In recent years, polybenzimidazole found its application as membrane in fuel cells. Polycarbonate (PC) thermoplastics are known under trademarks such as Lexan, Makrolon, Makroclear, and arcoPlus. They are easily worked, molded, and thermoformed for many applications, such as electronic components, construction materials, data storage devices, automotive and aircraft parts, check sockets in prosthetics, and security glazing. Polycarbonates do not have

484-428: Is a tough, lightweight material that is durable, fairly rigid and versatile, and is resistant to acids and bases. Much of it is used by the construction industry, such as for vinyl siding, drainpipes, gutters and roofing sheets. It is also converted to flexible forms with the addition of plasticizers, thereby making it useful for items such as hoses, tubing, electrical insulation, coats, jackets and upholstery. Flexible PVC

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528-421: Is also used in inflatable products, such as water beds and pool toys. PVC is also a common material in vinyl action figures , especially in countries such as Japan , where the material is used extensively in so-called Sofubi figures (Soft vinyl toys ). As PVC bends easily and has a tendency to be bent during transit, a method to mitigate this deformation is to heat the plastic until it becomes mobile, then reform

572-422: Is an engineering thermoplastic used in precision parts requiring high stiffness, low friction, and excellent dimensional stability. As with many other synthetic polymers, it is produced by different chemical firms with slightly different formulas and sold variously by such names as Delrin, Celcon, Ramtal, Duracon, Kepital and Hostaform. Polyether ether ketone (PEEK) is a colourless organic thermoplastic polymer in

616-420: Is an inexpensive plastic it is made in large amounts to cater to the demand. For example: Polyphenylene oxide (PPO), which is obtained from the free-radical, step-growth oxidative coupling polymerization of 2,6-xylenol, has many attractive properties such as high heat distortion and impact strength, chemical stability to mineral and organic acids, and low water absorption. PPO is difficult to process, and hence

660-653: Is any plastic polymer material that becomes pliable or moldable at a certain elevated temperature and solidifies upon cooling. Most thermoplastics have a high molecular weight . The polymer chains associate by intermolecular forces , which weaken rapidly with increased temperature, yielding a viscous liquid. In this state, thermoplastics may be reshaped, and are typically used to produce parts by various polymer processing techniques such as injection molding , compression molding , calendering , and extrusion . Thermoplastics differ from thermosetting polymers (or "thermosets"), which form irreversible chemical bonds during

704-519: Is commonly used in water, chemical, hot and cold, delivery systems for residential, commercial, and industrial applications. Poly vinylidene fluoride , PVDF , belongs to the fluoropolymer class of thermoplastics and is known for its high chemical inertness and resistance. PVDF is obtained through the polymerization of the vinylidene fluoride monomer. PVDF thermoplastic is fabricated into sheets and pipes for engineering uses as well as powders and coatings that can be dissolved in solvents and applied across

748-493: Is defined by the recyclable plastic number 5. Although relatively inert, it is vulnerable to ultraviolet radiation and can degrade considerably in direct sunlight. Polypropylene is not as impact-resistant as the polyethylenes (HDPE, LDPE). It is also somewhat permeable to highly volatile gases and liquids. Polystyrene is manufactured in various forms that have different applications and can have medium to very low density. Extruded polystyrene (PS or xPS, sometimes colored pink/blue)

792-657: Is extensively used to make signs, including lettering and logos. In medicine, it is used in bone cement and to replace eye lenses. Acrylic paint consists of PMMA particles suspended in water. For many decades, PMMA has been the predominant methacrylic ester produced worldwide. Major players in the PMMA market are Mitsubishi Rayon (Japan), Arkema SA (France), LG MMA (South Korea), Chi Mei Corp. (Taiwan), Sumimoto Chemical Company Ltd (Japan), Evonik Industries (Germany), BASF (Germany), Dow Chemical Company (U.S.), AkzoNobel (The Netherlands), Quinn Plastics (UK) and Cytec Industries (U.S.). Regarding

836-491: Is in prototype parts early in the design cycle such as for investment casting patterns, automotive hardware, and wind tunnel models. SLS is also increasingly being used in limited-run manufacturing to produce end-use parts for aerospace, military, medical, pharmaceutical , and electronics hardware. On a shop floor, SLS can be used for rapid manufacturing of tooling, jigs , and fixtures . Carl R. Deckard Carl Robert Deckard , Ph.D, ME (1961 - December 23, 2019)

880-439: Is necessary, as light is scattered strongly by crystallites larger than its wavelength. Amorphous and semi-amorphous plastics are less resistant to chemical attack and environmental stress cracking because they lack a crystalline structure. Brittleness can be decreased with the addition of plasticizers , which increases the mobility of amorphous chain segments to effectively lower the glass transition temperature. Modification of

924-401: Is often referred to as unplasticized polyvinyl chloride (uPVC), which is the more commonly used type for installations such as water, waste, and sewer conveyance plumbing. Chemical modification often produces more drastic changes in properties. Chlorinated polyvinyl chloride (CPVC) is produced through exposing PVC to the continued free-radical chlorination reaction that originally formulates

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968-503: Is principally used in coating applications. This is done by spraying an aqueous slurry of PPS particles and heating to temperatures above 370 °C. Particular grades of PPS can be used in injection and compression molding at temperatures (300 to 370 °C) at which PPS particles soften and undergo apparent crosslinking. Principal applications of injection and compression molded PPS include cookware, bearings, and pump parts for service in various corrosive environments. Polypropylene (PP)

1012-481: Is used in many consumer products, such as toys, appliances, and telephones. Nylon belongs to a class of polymers called polyamides . It has served as a substitute mainly for hemp, cotton and silk, in products such as parachutes, cords, sails, flak vests and clothing. Nylon fibres are useful in making fabrics, rope, carpets and musical strings, whereas, in bulk form, nylon is used for mechanical parts including machine screws, gears and power tool casings. In addition, it

1056-469: Is used in the manufacture of disposable cutlery, rigid ground contact rated insulating foam board, CD and DVD cases, plastic models of cars and boats, and smoke detector housings. Expanded polystyrene foam (EPS or "styrofoam", white) is used in making insulation and packaging materials, such as the "peanuts" and molded foam used to cushion fragile products. Polystyrene copolymers are used in the manufacture of toys and product casings. Polyvinyl chloride (PVC)

1100-683: Is used in the manufacture of heat-resistant composite materials. Polylactic acid (polylactide) is a compostable thermoplastic aliphatic polyester derived from renewable resources , such as corn starch (in the United States), sugar beet pulp (in Europe), tapioca roots, chips or starch (mostly in Asia), or sugarcane . It is the most common material used for 3D printing with fused deposition modeling (FDM) techniques. Polybenzimidazole (PBI, short for Poly-[2,2’-(m-phenylen)-5,5’-bisbenzimidazole]) fiber

1144-508: Is useful for such diverse products as reusable plastic food containers, microwave- and dishwasher-safe plastic containers , diaper lining, sanitary pad lining and casing, ropes, carpets, plastic moldings, piping systems, car batteries , insulation for electrical cables and filters for gases and liquids. In medicine, it is used in hernia treatment and to make heat-resistant medical equipment. Polypropylene sheets are used for stationery folders and packaging and clear storage bins. Polypropylene

1188-414: The polyacrylic acids (PAA) and its ester derivatives (PAc) market, on the other hand, the poly(methyl methacrylate) (PMMA) market. PMMA is also known by trade names such as Lucite, Perspex and Plexiglas. It serves as a sturdy substitute for glass for items such as aquariums, buttons, motorcycle helmet visors, aircraft windows, viewing ports of submersibles, and lenses of exterior lights of automobiles. It

1232-478: The PAA and PAc market, key manufacturers are Nippon Shokubai Company Ltd. (Japan), Arkema SA (France) and Dow Chemical Company (U.S.) Acrylonitrile butadiene styrene (ABS) is a terpolymer synthesized from styrene and acrylonitrile in the presence of polybutadiene . ABS is a light-weight material that exhibits high impact resistance and mechanical toughness. It poses few risks to human health under normal handling. It

1276-573: The PVC polymer. The chlorination reaction continues to add chlorine atoms to the polymer hydrocarbon backbone until most commercial applications reach a percent range between 56 and 74% total chlorine. This increase in elemental chlorine content contributes to CPVC's increased expression of chlorine-based characteristics, such as chemical durability, resistance to acids, bases, and salts; susceptibility to ammonia-based compounds, aromatics, esters, ketones; chemical stability; heat energy transfer resistance. CPVC

1320-409: The SLS process. Chemical binder coatings can be applied to the powder surfaces post-process; these coatings aid in the sintering process and are especially helpful to form composite material parts such as with alumina particles coated with thermoset epoxy resin . Sintering in SLS primarily occurs in the liquid state when the powder particles forms a micro-melt layer at the surface, resulting in

1364-485: The boundaries of the machine. One design aspect which should be observed however is that with SLS it is 'impossible' to fabricate a hollow but fully enclosed element. This is because the unsintered powder within the element could not be drained. Since patents have started to expire, affordable home printers have become possible, but the heating process is still an obstacle, with a power consumption of up to 5 kW and temperatures having to be controlled within 2 °C for

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1408-428: The commercial resin (Noryl) is made by blending PPO with high-impact polystyrene (HIPS), which serves to reduce the processing temperature. Polyphenylene sulfide (PPS) obtained by the condensation polymerization of p-dichlorobenzene and sodium sulfide, has outstanding chemical resistance, good electrical properties, excellent flame retardance, low coefficient of friction and high transparency to microwave radiation. PPS

1452-504: The curing process. Thermosets do not melt when heated, but typically decompose and do not reform upon cooling. Above its glass transition temperature and below its melting point , the physical properties of a thermoplastic change drastically without an associated phase change . Some thermoplastics do not fully crystallize below the glass transition temperature, retaining some or all of their amorphous characteristics. Amorphous and semi-amorphous plastics are used when high optical clarity

1496-678: The development of selective laser melting . Powder particles are typically produced by cryogenic grinding in a ball mill at temperatures well below the glass transition temperature of the material, which can be reached by running the grinding process with added cryogenic materials such as dry ice (dry grinding), or mixtures of liquid nitrogen and organic solvents (wet grinding). The process can result in spherical or irregular shaped particles as low as five microns in diameter. Powder particle size distributions are typically gaussian and range from 15 to 100 microns in diameter, although this can be customized to suit different layer thicknesses in

1540-504: The home market for SLS printing is not as large as the market for other additive manufacturing technologies, such as Fused Deposition Modeling (FDM). An additive manufacturing layer technology, SLS involves the use of a high power laser (for example, a carbon dioxide laser ) to fuse small particles of plastic , metal , ceramic , or glass powders into a mass that has a desired three-dimensional shape. The laser selectively fuses powdered material by scanning cross-sections generated from

1584-428: The material into the desired shape. PVC is produced in many specific modifications to affect its chemical and physical properties. In plasticized polyvinyl chloride (pPVC), plasticizers are added to the raw material before molding to make it more flexible or pliable. Early on, the health and environmental aspects of this were poorly understood and replacements and product bans resulted after studies. The original form

1628-402: The melting temperature of the material. The principal driving force behind the process is again the material's response to lower its free energy state resulting in diffusion of molecules across particles. SLS technology is in wide use at many industries around the world due to its ability to easily make complex geometries with little to no added manufacturing effort. Its most common application

1672-559: The most commonly used SLS materials due to their ideal sintering behavior as a semi-crystalline thermoplastic , resulting in parts with desirable mechanical properties. Polycarbonate (PC) is a material of high interest for SLS due to its high toughness, thermal stability, and flame resistance; however, such amorphous polymers processed by SLS tend to result in parts with diminished mechanical properties, dimensional accuracy and thus are limited to applications where these are of low importance. Metal materials are not commonly used in SLS since

1716-427: The part being constructed is surrounded by unsintered powder at all times. This allows for the construction of previously impossible geometries. Also, since the machine's chamber is always filled with powder material the fabrication of multiple parts has a far lower impact on the overall difficulty and price of the design because through a technique known as ' Nesting ', where multiple parts can be positioned to fit within

1760-696: The polyaryletherketone (PAEK) family, used in engineering applications. It was originally introduced by Victrex PLC, then ICI (Imperial Chemical Industries) in the early 1980s. It has attractive properties like good abrasion resistance, low flammability and emission of smoke and toxic gases. Polyetherimide (PEI), produced by a novel nitro displacement reaction involving bisphenol A, 4, 4’-methylenedianiline and 3-nitrophthalic anhydride, has high heat distortion temperature, tensile strength and modulus. They are generally used in high performance electrical and electronic parts, microwave appliances, and under-the-hood automotive parts. Polyethylene (polyethene, polythene, PE)

1804-494: The polymer through copolymerization or through the addition of non-reactive side chains to monomers before polymerization can also lower it. Before these techniques were employed, plastic automobile parts would often crack when exposed to cold temperatures. These are linear or slightly branched long chain molecules capable of repeatedly softening on heating and hardening on cooling. Today's acrylics industry can be divided into two distinct multibillion-dollar markets: on one hand

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1848-701: The three stages of preheating, melting and storing before removal. [1] Archived 2015-04-28 at the Wayback Machine The quality of printed structures depends on the various factors include powder properties such as particle size and shape, density, roughness, and porosity. Furthermore, the particle distribution and their thermal properties affect a lot on the flowability of the powder. Commercially-available materials used in SLS come in powder form and include, but are not limited to, polymers such as polyamides (PA), polystyrenes (PS), thermoplastic elastomers (TPE), and polyaryletherketones (PAEK). Polyamides are

1892-426: Was an American inventor, teacher, and businessman, best known for inventing and developing Selective Laser Sintering (SLS) , a method of 3D printing . He died at the age of 58, on 23 December 2019. Deckard initially came up with the idea for SLS as an undergraduate at the University of Texas at Austin (UT Austin). He continued developing the technology as a Masters and PhD student with the help of Dr. Joe Beaman,

1936-439: Was issued January 28, 1997 and expired January 28, 2014. A similar process was patented without being commercialized by R. F. Housholder in 1979. As SLS requires the use of high-powered lasers it is often too expensive, not to mention possibly too dangerous, to use in the home. The associated expense and potential danger of SLS printing due to lack of commercially available laser systems with Class-1 safety enclosures means that

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