Selective laser sintering

Selective laser sintering
Name	Selective laser sintering
Classification	Additive manufacturing
Invented	1980s
Inventor	Carl Deckard
Company	DTM Corporation
Application	Prototyping, tooling, production
Material	Polymers, metals, ceramics

Selective laser sintering

Selective laser sintering is an additive manufacturing technique developed in the 1980s for fabricating three-dimensional objects by sintering powdered material layer by layer with a laser. It emerged from research programs and startup ventures in North Carolina and Germany and has since influenced industries ranging from aerospace to medical devices. This entry summarizes the technology's origins, processing workflow, hardware, industrial uses, benefits, constraints, and safety considerations.

History

Development of the method traces to academic and commercial efforts in the 1980s involving researchers and institutions such as University of Texas at Austin, Duke University, North Carolina State University, Carl Deckard, and companies including DTM Corporation and 3D Systems. Early milestones intersect with innovations at Massachusetts Institute of Technology, Hewlett-Packard, General Electric, and research funded by U.S. agencies like the Defense Advanced Research Projects Agency and the National Science Foundation. Technology transfer, patent activity, and corporate acquisitions connected firms such as Optomec, EOS GmbH, Stratasys Ltd., Renishaw plc, and Siemens with academic groups at Carnegie Mellon University, Georgia Institute of Technology, Stanford University, and Imperial College London. International collaborations and conferences hosted by organizations such as ASTM International, ISO, and Society of Manufacturing Engineers shaped standardization efforts alongside regulatory attention from agencies like the U.S. Food and Drug Administration for medical applications. Commercial adoption accelerated through partnerships with aerospace primes like Boeing, Airbus, Rolls-Royce, and defense contractors including Lockheed Martin and Northrop Grumman.

Process and Materials

The core workflow involves digital model preparation in software from vendors such as Autodesk, Dassault Systèmes, Siemens PLM Software, and PTC, slicing into layers before material deposition. Powder feedstocks include thermoplastics developed by chemical firms like BASF, DuPont, Evonik Industries, and metal powders supplied by specialists like Carpenter Technology Corporation, Alcoa, ArcelorMittal, Sandvik, GKN Powder Metallurgy, and Höganäs AB. Ceramic powders and composites come from providers such as 3M and Morgan Advanced Materials. Process parameters—laser power, scan speed, hatch spacing—are managed with control systems from National Instruments or embedded controllers used by industrial OEMs like Trumpf and Mitsubishi Heavy Industries. Post-processing workflows often involve debinding and sintering ovens from companies like Carbolite Gero and surface finishing by firms such as GE Additive or contract manufacturers including Jabil, Flex Ltd., and Proto Labs.

Machine Components and Operation

Key hardware components—laser sources, optics, powder delivery, recoating mechanisms, build platforms, and inert gas systems—are produced by specialists such as Coherent Inc., IPG Photonics, Thorlabs, Zeiss, Schneider Electric, and industrial integrators like EOS GmbH and Renishaw plc. Motion control and gantry systems come from vendors such as Bosch Rexroth and Rockwell Automation. Industrial control software, human-machine interfaces, and quality assurance integrate instruments from Mitutoyo, Hexagon AB, FARO Technologies, and metrology labs like National Institute of Standards and Technology. Typical operation sequences include powder recoating, selective laser scanning, platform lowering, and repeating cycles under inert atmospheres supplied by Air Liquide or Linde plc. Safety subsystems reference standards promulgated by IEC and OSHA and certification by bodies such as Underwriters Laboratories.

Applications

Industries using the method include aerospace with companies like Boeing, Airbus, Safran, and Pratt & Whitney; automotive with BMW, Ford Motor Company, General Motors, and Volkswagen Group; medical with Stryker, Zimmer Biomet, Medtronic, and academic hospitals like Mayo Clinic and Cleveland Clinic; and energy sectors involving Schlumberger and Siemens Energy. Use cases span functional prototypes, end-use parts, conformal cooling molds for firms like HASCO, lattice structures for companies such as Arup, and surgical implants developed in collaboration with regulators including the U.S. Food and Drug Administration. Research partnerships with institutions like Lawrence Livermore National Laboratory, Oak Ridge National Laboratory, and Fraunhofer Society advance materials and process models, often resulting in commercialization via startups incubated by Y Combinator and accelerators associated with Lockheed Martin Ventures and GE Ventures.

Advantages and Limitations

Advantages highlighted by users including industrial adopters Boeing and Rolls-Royce are the ability to produce complex geometries, consolidate assemblies, and reduce lead time relative to conventional machining used by firms like MSC Industrial Supply Co. and Sandvik Coromant. Limitations reported by manufacturers such as GM and research centers like MIT Lincoln Laboratory include surface finish, powder recyclability constraints, residual stresses necessitating heat treatment in furnaces from Carbolite Gero, and high capital and material costs addressed by procurement teams at Honeywell and ABB. Supply chain considerations involve metal powder certification by entities like NIST and material traceability tracked by enterprise systems from SAP and Oracle Corporation.

Safety and Environmental Considerations

Operational safety policies reference occupational standards enforced by OSHA, NIOSH, and directives from European Agency for Safety and Health at Work. Hazards include fine particulate inhalation from powders supplied by Höganäs AB and flammable dust handled with guidance from NFPA and fire suppression systems by Tyco International. Laser safety follows classifications and controls advised by IEC and administered through institutional programs at Johns Hopkins Hospital and industrial plants of GE Aviation. Environmental impacts and recycling initiatives involve material stewardship with partners such as BASF, Veolia, and research into circular economy practices championed by Ellen MacArthur Foundation and policy work at the European Commission. End-of-life management and life-cycle assessment collaborations include academic groups at University of Cambridge and ETH Zurich.

Category:Additive manufacturing