3D PRINT TECHNOLOGY
From prototypes to end use products
Since the 1980’s, 3d printing has been used mostly by Engineers to develop rapid prototypes for their designs. The ability to be able to produce components without requiring an expensive and time consuming mould has dramatically increased the rate at which prototypes can be manufactured, refined and then remanufactured, and as such, the technology has dramatically reduced the time to market for many products. The next phase of the technology is upon us currently, when the technology can be used to produce end use products as well as prototypes.
There are different 3d Printing Technologies
There are a number of different technologies employed in 3d printing machines. All use the same concept of slicing up the models however, each of them varies in the way the layers are bonded together and in the materials that are used. A brief summary of the main technologies is presented below. Different manufacturers often use proprietary names for these processes but despite that, they remain fundamentally the same.
An SLA 3d printer works by concentrating a beam of ultraviolet light focused onto the surface of a vat filled with liquid photocurable resin. The UV laser beam draws out the 3d model one thin slice at a time, hardening that slice of the eventual 3d model as the UV light hits the resin. Slice after slice is created, with each one bonded to the other. Eventually you have a full, extremely high-resolution three dimensional model lifted out of the vat. Unused resin is reusable for the next job.
Selective Laser Sintering (SLS)
SLS works similarly to SLA, but instead of liquid photopolymer in a vat, you’ll find powdered materials, such as polystyrene, ceramics, glass, nylon, and metals including steel, titanium, aluminum, and silver. When a concentrated laser hits the powder, the powder is fused at that location (sintered). All unsintered powder remains as is, and becomes a support structure for the object. All unused powder can be used for the next print.
Much like a traditional inkjet printer deposits ink, a photopolymer liquid is precisely jetted out and then hardened with a UV light. The layers are printed successively. The technology allows for various materials and colors to be incorporated into single prints, and at high resolutions.
Almost any material that has a creamy viscosity can be used in 3d printers equipped with syringe extruders. This includes materials like clay, cement, silicone, and Play-Doh. Certain foods like chocolate, frosting, and cheese can also be printed with these systems. The syringe may or may not need to be heated, depending on the material; chocolate may need to be kept warm while silicone can be kept at room temperature.
There are other variants of these technologies. For example there is Selective Laser Melting (SLM), which is like SLS but it fully melts the powder rather than just fusing the powder granules at a lower temperature. This is similar to Electron Beam Melting (EBM) which uses an electron beam instead of a UV laser. And then there is a completely different technology called Laminated Object Manufacturing (LOM), where layers of adhesive-coated paper, plastic, or metal laminates are successively glued together and cut to shape with a knife or laser cutter.
Fused Deposition Modelling (FDM)
With FDM, the object is produced by extruding a stream of melted thermoplastic material to form layers. Each layer stacks more on top of, and fuses with, the previous layer. The material hardens almost immediately after leaving the extrusion nozzle. It is one of the less expensive 3D printing methods. Most FDM printers print with ABS plastic (think Lego), as well as PLA (Polylactic acid), a biodegradable polymer, which can be produced from organic material.