Barely a decade ago, 3D printers were hulking, expensive machines reserved for factories and well-heeled corporations. They were all but unknown outside the small circles of professionals who built and used them. But thanks largely to the RepRap open-source 3D printing movement, these amazing devices have become viable and affordable products for use by designers, engineers, hobbyists, schools, and even curious consumers.
If you're in the market for one, it's important to know how 3D printers differ from one another so you can choose the right model. They come in a variety of styles, and may be optimized for a particular audience or kind of printing. Preparing to take the plunge? Here's what you need to consider.
What Do You Want to Print?
Tied into the matter of what you want to print is a more fundamental question: Why do you want to print in 3D? Are you a consumer interested in printing toys and/or household items? A trendsetter who enjoys showing the latest gadgetry to your friends? An educator seeking to install a 3D printer in a classroom, library, or community center? A hobbyist or DIYer who likes to experiment with new projects and technologies? A designer, engineer, or architect who needs to create prototypes or models of new products, parts, or structures? An artist who seeks to explore the creative potential of fabricating 3D objects? Or a manufacturer, looking to print plastic items in relatively short runs?
Your optimal 3D printer depends on how you plan to use it. Consumers and schools will want a model that's easy to set up and use, doesn't require much maintenance, and has reasonably good print quality. Hobbyists and artists may want special features, such as the ability to print objects with more than one color, or to use multiple filament types. Designers and other professionals will want outstanding print quality. Shops involved in short-run manufacturing will want a large build area to print multiple objects at once. Individuals or businesses wanting to show off the wonders of 3D printing to friends or clients will want a handsome yet reliable machine.
For this guide, we will focus on 3D printers in the sub-$4,000 range, targeted at consumers, hobbyists, schools, product designers, and other professionals, such as engineers and architects. The vast majority of printers in this range build 3D objects out of successive layers of molten plastic, a technique known as fused filament fabrication (FFF). It is also frequently called Fused Deposition Modeling (FDM), although that term is trademarked by Stratasys, Inc. (Although they are not strictly 3D printers, we also include 3D pens—in which the "ink" is molten plastic and the user applies it by drawing freehand or using a stencil—in this roundup.) A few 3D printers use stereolithography—the first 3D printing technique to be developed—in which ultraviolet (UV) lasers trace a pattern on a photosensitive liquid resin, hardening the resin to form the object.
What Size Objects Do You Want to Print?
Make sure that a 3D printer's build area is large enough for the kind of objects that you intend to print with it. The build area is the size, in three dimensions, of the largest object that can be printed with a given printer (at least in theory—it may be somewhat less if the build platform is not exactly level, for example). Typical 3D printers have build areas between 6 and 9 inches square, but they can range from a few inches up to more than 2 feet on a side, and a few are actually square. In our reviews, we provide the build area in inches, in height, width, and depth (HWD).
What Materials Do You Want to Print With?
Most lower-priced 3D printers use the FFF technique, in which plastic filament, available in spools, is melted and extruded, and then solidifies to form the object. The two most common types of filament by far are acrylonitrile butadiene styrene (ABS) and polylactic acid (PLA). Each has slightly different properties. For example, ABS melts at a higher temperature than PLA and is more flexible, but it emits fumes when melted that many users find unpleasant, and it needs a heated print bed. PLA prints look smooth, but they tend to be on the brittle side.
Other materials used in FFF printing include, but are not limited to, high-impact polystyrene (HIPS), wood, bronze, and copper composite filaments, UV-luminescent filaments, nylon, Tritan polyester, polyvinyl alcohol (PVA), polyethylene terephthalate (PETT), polycarbonate, conductive PLA and ABS, plasticized copolyamide thermoplastic elastomer (PCTPE), and PC-ABS. Each material has a different melt point, so use of these exotic filaments is limited to printers designed for them, or ones with software that lets users control the extruder temperature.
Filament comes in two diameters—1.85mm and 3mm—with most models using the smaller-diameter filament. Filament is sold in spools, generally 1kg (2.2 pounds), and sells for between $20 and $50 per kilogram for ABS and PLA. Although many 3D printers will accept generic spools, some companies' 3D printers use proprietary spools or cartridges. These often contain an RFID chip that allows a printer to identify the filament type and properties, but this only works for that manufacturer's compatible printers. Make sure that the filament is the right diameter for your printer, and that the spool is the right size. In many cases, you can buy or make (even 3D print) a spool holder that will fit various spool sizes. (For much more on 3D printing filaments, check out our filament explainer.)
Stereolithography printers can print at high resolutions and eschew filament in favor of photosensitive (UV-curable) liquid resin, which is sold in bottles. Only a limited color palette is available: mainly clear, white, gray, black, or gold. Working with liquid resin and isopropyl alcohol, which is used in the finishing process for stereolithography prints, can be messy and odiferous.
How High of a Resolution Do You Need?
A 3D printer extrudes successive thin layers of molten plastic in accordance with instructions coded in the file for the object being printed. For 3D printing, resolution equals layer height. Resolution is measured in microns, with a micron being 0.001mm, and the lower the number, the higher the resolution. That's because the thinner each layer is, the more layers are needed to print any given object, and the finer the detail that can be captured. Note, however, that increasing the resolution is sort of like increasing a digital camera's megapixel count: Although a higher resolution often helps, it doesn't guarantee good print quality.
Nearly all 3D printers being sold today can print at a resolution of 200 microns—which should produce decent-quality prints—or better, and many can print at 100 microns, which generally delivers good-quality prints. A few can print at higher resolutions still, as fine as 20 microns, but you may have to go beyond the preset resolutions and into custom settings to enable resolutions finer than 100 microns.