3D printing

3D printing
Name	3D printing
Caption	A stereolithography apparatus (SLA) printer in operation.
Other names	Additive manufacturing, rapid prototyping
Inventor	Hideo Kodama, Chuck Hull
Inception	1981 (first concept), 1984 (first patent)
Related technologies	Computer-aided design, CNC machining, Injection molding

3D printing. Also known as additive manufacturing, it is a process of creating three-dimensional objects from a digital file by successively adding material layer by layer. This contrasts with traditional subtractive manufacturing methods like CNC machining. The technology has evolved from a tool for rapid prototyping to a means of producing end-use parts and complex geometries impossible with conventional techniques, impacting fields from aerospace to biomedical engineering.

History

The foundational concepts emerged in the early 1980s. In Japan, Hideo Kodama of the Nagoya Municipal Industrial Research Institute published early work on a photopolymer rapid prototyping system. Shortly after, in the United States, Chuck Hull of 3D Systems Corporation invented stereolithography (SLA), filing his patent in 1984 and commercializing the first system in 1987. The late 1980s and 1990s saw the development of other core technologies, including fused deposition modeling (FDM) by Scott Crump of Stratasys and selective laser sintering (SLS) at the University of Texas at Austin. The 2009 expiration of key FDM patents catalyzed the rise of the low-cost RepRap project and the consumer desktop market, with companies like MakerBot Industries driving wider adoption.

Process

The process universally begins with a digital 3D model, typically created using Computer-aided design software like Autodesk Fusion 360 or SolidWorks, or generated from 3D scan data. This model is then digitally sliced into thin horizontal cross-sections by specialized software, such as Ultimaker Cura or PrusaSlicer. The printer reads this sliced data and proceeds to fabricate the object, depositing, fusing, or solidifying material one layer at a time, with each layer bonding to the preceding one. Post-processing steps, which may include support removal, sanding, or curing, are often required to achieve the final desired properties and surface finish.

Technologies

Several distinct technologies have been developed, each employing different methods to form layers. Vat photopolymerization, including stereolithography (SLA) and digital light processing (DLP), uses a light source to cure liquid photopolymer resin. Material extrusion, most commonly fused deposition modeling (FDM), feeds a thermoplastic filament through a heated nozzle. Powder bed fusion techniques, such as selective laser sintering (SLS) and direct metal laser sintering (DMLS), use a laser or electron beam to fuse powdered material. Other methods include material jetting, which operates similarly to inkjet printing, and binder jetting, which deposits a liquid binding agent onto a powder bed.

Materials

A vast and growing array of materials can be utilized, dictated by the printing technology. Common thermoplastics include polylactic acid (PLA), acrylonitrile butadiene styrene (ABS), and polyethylene terephthalate glycol (PETG). High-performance polymers like polyether ether ketone (PEEK) are used in demanding applications. Metals such as stainless steel, titanium alloys (e.g., Ti-6Al-4V), aluminum, and Inconel are processed via powder bed or directed energy deposition. Other materials encompass photopolymer resins, sandstone composites, carbon fiber-reinforced filaments, and even biomaterials like hydrogels for research in bioprinting.

Applications

Applications are pervasive across industrial, consumer, and research sectors. In aerospace and automotive, companies like SpaceX, General Electric, and BMW manufacture lightweight, complex components. The medical field uses it for patient-specific surgical guides, dental implants, hearing aid shells, and prosthetics. Architecture firms create detailed scale models, while the entertainment industry leverages it for special effects props and costume pieces. It is also fundamental to rapid prototyping in product design and enables distributed manufacturing through services like Shapeways and local Fab Lab networks.

Impacts and implications

The technology has significant economic, social, and environmental implications. It enables mass customization, reduces waste through additive processes, and can compress supply chains by facilitating on-demand, localized production. This has potential ramifications for global trade and logistics, challenging traditional models centered on injection molding and overseas factories. Socially, it empowers maker culture and DIY innovation but raises concerns regarding intellectual property, as seen in debates over digital files for items like firearm components. Environmental impacts are mixed, offering potential for lightweighting in transportation but also contributing to plastic waste if not managed responsibly. Ongoing research at institutions like Lawrence Livermore National Laboratory continues to advance the capabilities and address these complex challenges.

Category:Manufacturing Category:Industrial processes Category:Digital fabrication