The Different Methods of 3D Printing

In a recent blog we talked about the arrival of 3-D printing and how it’s going to literally change the world. Many people have asked about the different types of 3-D printers and 3-D printing methods on the market and, with that in mind, we put together today’s blog to explain a little bit about those methods and printers and how they work. Enjoy.

Back before they were even called 3-D printers there was a commercially available machine that used the process of Stereolithography (SLA). The founder of 3-D Systems, Mr. Charles Hull, invented this process in 1986. With a 3-D SLA printer ultraviolet light is concentrated into a beam and focused on a container that’s been filled with a resin called liquid photocurable photopolymer. Once focused on the surface, the UV laser basically draws, one thin layer at a time, the required 3-D model. As each slice is made it hardens as the light hits the resin and, slice after slice, you’ll eventually get a high resolution, extremely precise 3-D model. Any resin that’s left over can be reused on your next project as well.

A gentleman named Scott Crump invented Fused Deposition Modeling (FDM) in the late 1980s as well and, in 1988, founded the company Stratasys. With FDM, thermoplastic material is extruded in streams using a beam of laser light and, similar to other methods, the 3-D product is formed layer by layer. Each layer hardens almost instantaneously as the next is placed on top and, since most FDM laser printers use ABS plastic (the same kind used by Lego) and polylactic acid which is a biodegradable polymer, it’s one of the least expensive 3-D printing methods on the market. One thing about this type of printing that many like is that the polylactic acid used can be made from organic materials.

This technique is similar to one that was invented by the founder of RepRap, a popular home 3-D printer model. Their process is called fused filament fabrication (FFF) and, while it’s quite similar, the thermoplastic material that they use is fed via a filament from a spool of it into the 3-D printer.

3-D printing technology really took off during the 1980s and not only were the two types of processes above invented and patented during that time but so was another process called Selective Laser Sintering (SLS). A gentleman named Carl Deckard and a few of his colleagues from the University of Texas created this system that works similar to SLA. In this process however they use powdered materials like polystyrene, ceramic, nylon, glass and various metals rather than liquid photopolymer. The name sintering is used to describe what happens when the laser hits the powder and the powder is fused. When the printing process is complete the unsintered leftovers become part of the support structure for the newly created object, an advantage over the other methods because there’s nothing to remove after the object is printed. Since the unused powder can be used for creating something else, there’s also no waste.

Interestingly enough, practically any material with a creamy viscosity can be used if your a 3-D printer uses Syringe Extrusion. Materials like cement, Play Doh, Clay, silicone and even foods like frosting and cheese can be printed using a syringe extrusion system. Another interesting thing about this type of 3-D printing system is that the syringe can be heated when needed, for example when working with chocolate, but can also be kept at room temperature when working with materials like silicone. (We expect that the variety of television shows that feature cakes and cupcakes are going to explode in the next few years due to this new technology, as well as our waistlines.)

Other 3-D printing techniques include Selective Laser Melting (SLM) which fully melts the powder being used in the process rather than just using it together. There’s also Electronic Beam Melting (EBM) which, instead of using a UV laser, uses an electron beam in its place. Laminated Object Manufacturing (LOM) is similar in some ways but also completely different in others in that layers of paper, plastic or metal laminate are coated with an adhesive and then glued together, layer by layer, to get the finished product which is then cut into its final shape with a laser cutter or sometimes just a razor knife.

No matter which system of 3-D laser printing being used, the fact is that this technology is absolutely amazing and has already brought about astounding changes in many fields, including medicine, manufacturing and even the arts. You can expect that, in the next few years, there will be an explosion of 3-D printers for a home use and a similar explosion in new products that are developed by average guys and gals working in their home shop. Interesting times indeed, to say the least.