L-R: Ultimaker 2, Printrbot Simple Maker, Formlabs Form 1+
The future is here: 3D printers that can build objects on demand are not just available, but also affordable. This emerging area of technology offers a lot of potential, but also many pitfalls. So, what do you need to know, and which 3D printer is the right one for you?
The first thing you will need is patience. 3D printing is an area that's developing very quickly, but the 3D printers you can buy now are a long way from the replicators of Star Trek fame. They print slowly — often taking many hours to produce a single object — and they offer a limited range of materials (most use two types of plastic, called PLA and ABS).
MORE: Best 3D Printers
Even the best consumer 3D printers can only build objects up to the size of a loaf of bread, and cheaper models have smaller build areas that usually measure only a few inches on each side. But these printers can create objects of surprising strength, smoothness and clarity that can be very useful around the home, ranging from custom salt-and-pepper shakers to homemade replacements for hard-to-find parts.
How 3D Printing Works
To start, you need a model of the object you want to build. This can be a model that you make yourself in 3D-modeling software, such as Blender; a 3D scan of an existing object; or a model that you download from the Internet.
The free 123Design app by AutocadThe software that works with the printer then takes this model and slices it, converting it into a series of thin layers that the 3D printer can print, one at a time. This is why some 3D-printed objects have a stair-step look to them, formed by the layers stacked on top of one another.
MakerBot Digitizer: Original shell (left) and 3D-printed copy made from scan. Paint can add detail. | Credit: Sean CaptainHow the 3D printer prints these slices to form the final model varies. Most consumer models are filament printers, which use a thin string of plastic that is melted in the extruder, where the molten plastic drops onto the building surface. More-advanced (and expensive) 3D printers use a resin, and the most-expensive models use a powder that is melted or liquefied (and then quickly hardens) to bind to the layer below it.
Most 3D printers come fully assembled and ready to print, but some are sold as kits that you assemble yourself. The prebuilt models are easier start with, but the kits offer better insight into how these printers work, and allow you to customize and tweak them yourself when they are up and running. There are a lot of parts, but most kits require just basic mechanical knowledge: If you've put together an Ikea bookshelf, you can build a 3D-printer kit.
The Printrbot Simple Maker’s Kit costs $349.Although 3D printers currently have some limitations, these devices are the vanguard of a technology and design revolution in which you can make what you want, when you want it. Let’s run down the different types of 3D printers and the advantages and disadvantages of each.
Types of 3D Printers
Entry-Level Filament 3D Printers
Price Range: $350 to $1,500
The cheapest 3D printers are simple models, like the $749 Printrbot Simple with Heated Bed or the $999 Cubify Cube 3 (see review). These printers use a process typically called filament deposition manufacturing (FDM). A plastic filament is melted and then deposited in thin layers that build up the model. There are two possible types of plastic: ABS, or an organic version known as PLA. Budget printers have a single nozzle for laying down the filament.
Pros: Low-cost, simple printers are an ideal entry point for 3D printing. They are usually relatively straightforward to set up and configure.
Cons: This type of 3D printer prints only one color or material at a time, and the build area is usually fairly small — typically about 4 x 4 x 4 inches (10 x 10 x 10 centimeters).
Key Features & Accessories: Most printers of this type include basic software, but some come with no software, leaving you to find open-source solutions. They typically use 1.75 or 3mm filament, which is widely available on rolls in a range of colors.
High-End Filament Printers
Price Range: $1,000 to $3,000
More sophisticated FDM filament printers, like the $2,500 Ultimaker 2 (see review) or the open-source RepRap Mendel ($1,595 for a kit), add extra features to the standard 3D filament printer, such as multiple extruders and thinner layers (down to 0.0039 inches, or 0.1 millimeters) for smoother prints.
Pros: Larger print areas mean bigger prints than their simpler cousins can produce. Multiple extruders mean multiple colors or materials in one object.
Cons: Higher cost. More sophisticated designs and parts can mean more parts that could break with heavy use.
Key Features & Accessories: The number of extruders, either included or available as an upgrade, and the improved vertical or Z resolution are the critical factors here. These models tend to offer larger build areas, often up to about 10 x 6 x 6 inches (25 x 15 x 15 cm).
Other-material FDM 3D Printers
Price Range: $2000 and up
Relatively low-cost printers that can use materials other than plastic are beginning to appear on the market. Hyrel offers an extruder on its E series printers — like the $1,245 E2 — that can print using any air-dried material, such as clay, Plasticine or the popular air-cured plastic Sugru. The Plasticine can be good for producing more flexible models, and Sugru is known for its elasticity. Unlike most printed plastics, Sugru can bend, stretch and flex almost like rubber.
Pros: Support for printing materials other than plastic means more flexible printing in a range of materials that may be more suited to the task at hand. You can print pots and dishes of air-dried clay, for instance.
Cons: Support for other materials is often experimental, so you have to figure out what they can (and can't) do.
Key Features & Accessories: Look for the number of extruders that the device can support, and the cost of these and other extras that might be needed for your materials.
Stereolithography (SLA) 3D Printers
Price Range: $3000 and up
New on the 3D printer market are models called Stereolithographic or SL printers, like the $3,299 Form 1+ (see review) or the B9Creator ($2,990 kit, $4,995 assembled), which use a photosensitive resin and a digital projector or laser. The light is shone on the resin in the pattern of the layer, causing it to solidify. The build surface is then lowered, and the light forms another layer until the object is complete. These printers can produce very-high-resolution objects, but the colors of the resin are limited.
Pros: Very high resolution, smooth prints, with details as fine as 0.012 inches (0.030 cm) and layers as thin as 0.001 inches (0.003 cm). The printing process is usually quicker than with FDM filament models.
Cons: Limited range of resin colors, and the newness of the technology makes both the printer and the print resin expensive.
Key Features & Accessories: The cost of the printer and the types of resin are the key considerations: For the Form 1+, the resin currently costs $149 per liter, and is available in only clear, white, gray and black. The build area is also a critical feature to consider; most offer small build areas of about 6 x 5 x 5 inches (15 by 13 by 13 cm).
Powder 3D Printers
Price Range: $10,000 and up
Another approach is called powder printing, in which a fine powder is spread over the print surface, and either a laser sinters (melts) the powder (a process called selective laser sintering or SLS), or a solvent liquefies the powder, causing it to bind together to form the layer. The advantage of powder printing is that it can support a wide range of materials, including metals, glass and plastics. By mixing different colors of powder, they are the only printers that can create custom-color 3D prints.
However, powder printers are more complex to build and need either a powerful laser or a solvent, so they are expensive. The Zprinter 150, for example, is still a commercial-grade machine and costs $11,000. Patient tinkerers can access the technology more affordably by building their own printer using the open-source design of the experimental pwdr printer.
Pros: The printer can make objects in multiple, customized colors by mixing different colored powders. Some models can print from powdered metals.
Cons: Currently, powder printers are either very expensive or only available as open-source designs that you can try to build yourself. The printing materials are also expensive.
Key Features & Accessories: As with all 3D printers, consider the size of the print area and the cost of printing. If you have to buy the printing material from one company (as you do with the ZCorp models), you should include this in your calculations, as the material is usually pretty expensive.
Important 3D Printer Features and Specs
Build Area: This is the maximum size of an object that the 3D printer can build. This is usually measured in XYZ dimensions, such as 8 inches wide (X) by 8 inches deep (Y) by 8 inches high (Z). A smaller build area can be limiting, but most print jobs can be split into smaller parts that can be combined afterward, so it may not be quite as limiting as it first appears. In general, look for a build area of at least 5 x 5 x 5 inches 13 x 13 x 13 cm), which should be large enough for most printed parts.
Extruders: The extruder is the business end of filament printers, where the printing material is melted and extruded to lay down each layer of an object. Most models have a single extruder, which means they can print in only one material or color at a time.
Filament Width: Most consumer 3D printers use a plastic filament, which is usually sold on 2.2-lb. (1 kilogram) rolls for about $40 to $60. This is available in two widths: 1.75 millimeters and 3 mm, with most printers using the 1.75-mm type. (The thickness of the layers that the printer uses is determined by the extruder, not the size of the filament.) With most printers, you can buy and use filament from any manufacturer. The exceptions are printers from Cubify and Stratasys, which use filament cartridges that you have to buy from the manufacturer, at a slightly higher cost.
Print Speed: This is the speed at which the extruder can move while laying down the print material for a filament printer. A faster print speed usually means quicker prints. However, the type of material used can also affect the print speed, and the complexity of the print can also slow down printing: Complex models with lots of edges make for slow prints. You should look for a top speed of at least 20 mm per second, if possible. Other printer types (such as SLA and SLS printers) don't measure speed in the same way.
Horizontal, XY or Feature Resolution: Like a paper printer, 3D printers have minimum resolutions that determine the level of detail they can produce. The horizontal (or XY) resolution is the smallest movement that the extruder or print head can make within a printed layer. A smaller horizontal or XY resolution means more fine detail in prints, so look for a measurement of at least 0.01 inches (0.03 cm).
Vertical Z Resolution or Layer Thickness: This is the minimum thickness of a layer that the 3D printer can lay down in one pass. A larger number for this means thicker, more obvious layers in the final print, while a small number means smoother, more realistic prints. Just keep in mind that the process will be slower, because the printer has to create more layers.
Most printers work with a layer thickness of 0.2 or 0.3 mm, but the ability to create 0.1 mm or smaller layers produces noticeably smoother models. Some printers allow you to adjust the layer thickness, so you can choose whether to make this trade-off.
3D Modeling Software
You can download digital files for printing from sites such as Thingiverse and Youmagine. But to customize them or go completely creative and design your own pieces, start with a simple, free 3D modeling app. We recommend any of the apps below. Give them a look and see which one works best for you.
3D Printing Services
Services such as Shapeways offer a wide range of product and material options.You can get started in 3D printing before you buy a printer, and without even knowing how to use modeling software. Companies such as Cubify (which also makes printers), Sculpteo and Shapeways allow you to chose designs from their websites, upload models you get from other sites such as Thingiverse.com, or upload your own creations for printing on their industrial-grade printers. These services offer options to print in materials other than plastic, including ceramic and even metal.