In her new book, 3D Printing Basics for Entertainment Design, Anne E. McMills takes her readers into the exciting realm of 3D printing. In this short excerpt from the book, McMills provides useful definitions of some of the basics of this cutting-edge technology. An author and lighting designer, she is also a professor and head of lighting at San Diego State University where she has been teaching 3D printing since 2011.
Excerpt adapted from 3D Printing Basics for Entertainment Design:
So, what exactly is 3D printing?
3D printing (often abbreviated as “3DP”) is a rather ambiguous term. In recent years, it has become a popular buzzword encompassing a mixed cocktail of manufacturing techniques and technologies.
There are four basic types of 3D printing methods at this time: Fused Deposition Modeling (FDM), Stereolithography (SLA), Granular Materials Binding (GMB), and Selective Deposition Lamination (SDL). All of these processes take a virtual model and build it – bit by bit – into a physical object.
Fused Deposition Modeling (FDM)
Fused Deposition Modeling (FDM) is a 3D printing process by which thermoplastic filament (or plastic that is malleable when heated) is extruded through a small nozzle into fine layers that stack upon each other to create an object.
Think of FDM like a really smart hot-glue gun. In the same way a glue stick is inserted into the back of a glue gun, thermoplastic filament is fed into the 3D printer. The printer heats up the plastic to a molten state and extrudes (or squeezes) it through a small nozzle – much like a hot-glue gun oozes molten glue when the trigger is pulled. A computer controls the 3D printer’s movement (based on your 3D model) and tells it to selectively deposit the molten plastic in the shape of the first layer of your object, which solidifies almost immediately as it cools. Then the next layer is extruded on top of the first layer, and so on. As the layers build on top of themselves – tiny layer by tiny layer – the physical object begins to take shape.
Stereolithography (SLA) 3D printers use a process called photopolymerization. This process uses a high-intensity energy or light source to cure a liquid photopolymeric resin into solid layers; a photopolymer is any material that can transform from a liquid to a solid almost instantaneously when stimulated by light. As each layer is “drawn” in the pool of resin by the light source, it solidifies.
SLA printers typically print more quickly than FDM printers. SLA also produces higher-resolution objects with exceptionally smooth surfaces. This level of detail can be an ideal for scenic model pieces in 1/4" scale – a scale with which the average FDM printer can struggle.
Granular Materials Binding (GMB)
Granular Materials Binding (GMB) uses a binding material (like a glue, for example) or an energy source (such as a laser or hot air) to selectively fuse layers of loose powder into a solid object.
Many different materials can be used as the powder base for GMB printers: among them are nylon, plaster, gypsum, ceramic, porcelain, resin, plastic, glass (although it turns out opaque), silica, sand, sugar, cement, concrete, and metals. Renewable resources can also be printed with GMB. Materials such as naturally occurring sea salt, tea, sawdust waste from lumberyards, recycled newspaper, pulverized concrete, fly ash (a waste material that results from burning coal), sand, and clay, have all been fodder for experimentation.
Selective Deposition Lamination (SDL)
Selective Deposition Lamination (SDL) uses a computer-controlled blade to cut out a three-dimensional object from a ream of standard office paper. As each layer is cut, water-based adhesives are selectively deposited on the paper.
Surprisingly for being made out of paper, SDL prints are extremely strong and durable – especially after applying thin layers of Super Glue to the object. Functional tools can even be printed—such as a 3D printed hammer capable of driving an actual nail into real wood! Full-color, photorealistic models can also be created—great for props!