As 3D printing begins to influence the lighting industry (beyond prototyping), a dizzying new array of approaches have been commercialized. A recent article in Laser Focus World lays out the many approaches.
Polymers:
- In the mid-1980’s, the first 3D printers were
- stereolithography and 3D extruded thermoplastic parts. Stereolithography was based on industrial lasers, as were a variety of later technologies for printing both polymers and metals.
- Vat photopolymerization (VPP) generally uses an ultraviolet (UV) light source to harden a photopolymer; heat can be used as an energy source as well. The VPP process, also known as stereolithography, uses a laser to cure a liquid resin layer by layer inside a build vat to form the object.
- Digital light processing (DLP) projector is an alternative light source to cure a photopolymer. These systems replaced laser-based stereolithography for certain applications. With some exceptions, DLP systems are used for building smaller parts than larger frame stereolithography. Small-part VPP is commonly used for a variety of dentistry applications.
- Powder bed fusion (PBF), or selective laser sintering (SLS) are a technology using laser energy to melt layers of powdered polymer, fusing them together, layer by layer to form parts. The most common material used for SLS is polyamide (PA) 12, also known as nylon.
- Material extrusion (MEX) and material jetting (MJT) round out the picture of polymer 3D printing. The former, widely referred to as fused deposition modeling (FDM), builds parts by extruding heat-melted thermoplastics through a nozzle. The latter uses industrial inkjet technology to selectively jet photopolymers onto a build plate, cured by exposure to UV light.
Metals and ceramics:
- The making of functional metal and ceramic parts has developed significantly in recent years, because prices for the underlying technologies have come down. PBF is by far the most common metal additive manufacturing (AM) process. Like its related process for polymers, a laser beam melts the metal powder inside an inert and heated build chamber to form the part.
- Directed-energy deposition (DED) is a group of processes characterized by melting a metal feedstock into metal parts via a process similar to welding. The feedstock could be provided by a metal wire or metal powder, and the thermal heat source for melting the feedstock can be supplied by a laser or an electron beam.
- Metal binder jetting offers the promise of lower-cost metal AM. Its growth has so far failed to live up to expectations, despite the entry of a number of new and well-funded companies developing this technology. This could be attributed to process issues related to handling green parts and, more importantly, the difficulty customers have inefficiently sintering the parts.
Read the full article, here.
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