The B&H 3D Printers Buying Guide

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The Process
Material
Build Space
Design Phase
Performance

When Gutenburg invented the printing press, the ability to print was limited to very few people. As a matter of fact, up until the invention of the typewriter, personal printing was fairly inaccessible, as well. The same hierarchy applies to 3D printing. Once the bastion of architectural firms, scientific and medical universities, and high-end art houses, 3D printing has dramatically changed in recent years with the availability of desktop 3D printers for professionals and hobbyists alike, leading to a revolution that enables everyone from manufacturers to students to dream in 3D, and see those dreams come to life.

The manufacturing industry has been building solid-model 3D prototypes designed on state-of-the-art equipment for several decades. Rapid prototyping, as it was once called, required engineers to create three-dimensional digital objects with a CAD (computer aided design) software program and output the final plastic or metal product using massive robotic machines. Outside of expense and size, object materials had a low resolution and low strength mass, limiting the technology to early design phase prototypes—these were not made for casual users. 

In more recent years, the introduction of tougher plastic materials that can withstand everyday use has advanced the game. The advent of thermoplastics and the development of smaller, more efficient machinery with faster output speeds have enabled 3D printers to leap from the factory floor to the office desktop in just a few years. 3D printing is an additive process of manufacturing in which consecutive layers of material are layered upon each other to create different shapes, textures, and forms, building toward a final detailed object. The detail on the object and the amount of layering and colors involved are all dependent on the rendering of the source 2D drawing or concept. Whether you're making chess pieces or artificial organs, the source material (and the complexity of the 3D printer, of course) determines the scope of the finished product.

There are six different types of 3D printing processes: photocurring, sintering, melting, lamination, jetting, and extrusion. For commercially available 3D printers, extrusion is the most common form and can be identified by different names, like Plastic Jet Printing (PJP), Fused Deposition Modeling (FDM), or Fused Filament Fabrication (FFF).
The extrusion method involves a continuous bead of thermoplastic material that is squeezed through an extruder, either by heat or pressure—think of the icing bag that a baker uses to pipe frosting onto a cake. 

With the drop in price of 3D printers, and continuous exposure in the press and on hobbyist blogs, consumer use has expanded tremendously. Applications include but are not limited to:

  • Educational - conceptual designs and engineering basics
  • Medical - implants, prosthetics, and 3D renderings of MRIs and CT scans 
  • Architecture - building and landscape models
  • Automotive & Manufacturing – making replacement parts instead of a lengthy order/manufacture process
  • Cameras - Lens hoods, cases, and other accessories 
  • Hobbies - Toys, models, game pieces, and prototypes
  • Fashion Design - Necklaces, rings, and earrings
  • Clothing – Footwear and footwear prototypes
  • Electronics - Phone and tablet cases
  • Food – 3D chocolate, sugar, and other food creations

The Process

The 3D printing process begins with your imagination. It begins as a two-dimensional design that is then structured as a 3D drawing using any number of software programs or a specially made 3D scanner. You can also share and purchase pre-made 3D designs from a number of online sources, like Thingiverse or Youmagine. Once it is digitally mastered in 3D, it is sent over to the printer, either via USB, SD card, Ethernet, or wirelessly, depending on the printer's capability.

 

The digital design is sliced in the modeling program into thin layers (measured in microns), which correspond to a virtual cross-section of the final 3D object. These individual sections are guides for the printer and determine how each layer is to be printed. Surprisingly, you don’t need a mathematical, engineering or art background to determine the shape and size of the individual layers—3D modeling programs show you what your end product will look like through a WYSIWYG (what you see is what you get) interface, much in the manner your computer screen does. 

 
 

The actual printing process starts after the machine reads the digital file and outputs a flexible thermoplastic filament material through an extruder or heated nozzle, producing hot beads of material that melt onto a flat plate and harden immediately. The extruder is attached to a mechanical motor, building the object in consecutive layers, horizontally, in a side-to-side (X axis) and front-to-back (Y axis) motion. The nozzle continues the horizontal motion as the build plate lowers while the print gains height, and builds the print vertically (z axis). Think of building a mountainous sandwich. You stack each piece of roast beef or salami layer by layer until you have a tower of deliciousness. When you are done, you have created a 3D model of your sandwich in almost the same way that a printer does—except yours is edible. With a 3D model, the material is fused together to build the final object according to the design’s specifications. Depending on the complexity of the final 3D object, the printing process can last several hours or more. If you build a small sandwich, you need fewer layers.

Material

There are several different materials available today, including metal and titanium alloys, plaster, laminate composites, and thermoplastics. Commercially available 3D printers use some type of thermoplastic filament, particularly polylactide (PLA) and Acrylonitrile butadiene styrene (ABS). Thermoplastics are soft and moldable in the hot printing stage but harden to a durable solid when cooled. 

 

Although PLA and ABS are both thermoplastic filaments, the differences between them could influence your purchase of a 3D printer. PLA is biodegradable material derived from renewable sources like corn and sugarcane, with a wider range of colors, translucency, glossier surfaces, and more detail. PLA also degrades into harmless lactic acid when its lifespan ends, so it used in the medical field, in the form of anchors, screws, plates, and mesh. Most PLA-based printers have faster print speeds, but PLA-based 3D print objects can become deformed when exposed to everyday heat, like that experienced in a hot car or stuffy attic. PLA can also be more brittle than ABS, with a penchant to snap instead of bend. A PLA print is a good option for objects larger than 100 x 100mm, making it a great choice for home use and schools. Since it doesn’t emit the noxious fumes associated with ABS printing, it can make food-safe and dishwasher-safe items like plates and utensils.

ABS PLA

ABS is a harder, petroleum-based material that gives off hot plastic fumes during the printing process, making it less environmentally friendly, and because of the oily fumes it gives off, it is recommended to print ABS objects in a well-ventilated area. The tougher material of ABS has a longer lifespan and is ideal for professional applications, such as replacement machine parts. ABS is also more flexible, which makes it ideal for moving parts, like gears and pulleys. With its high melting point, it won't deform in heat as easily as PLA material.

 

An additional variety of materials is now available at the consumer level of 3D printing with the ROBO 3D R1. In addition to printing both ABS and PLA, the R1 can also print T-Glase, wood, HIPS, and other flexible materials. 

 
 

Wood filament (aka Laywood) can be heated during the printing process and has a realistic grain that can be sanded, cut, and painted, and which even smells like wood. By adjusting the temperature during the print process, the surface color changes to match a more specifically desired wood type. 

 

Although T-Glase filaments are not biodegradable, they are made of FDA-approved polymers ideal for food containers. A colorless and odorless material, T-Glase is also used for clear jewelry pieces. Both Laywood and Glase-based filament materials do not give off dangerous fumes during the printing process.

 

The HIPS filament (High Impact Polystyrene) has properties similar to ABS, with the exception of using a limonene instead of the Acetone of ABS. With a dual extruder printer, HIPS can be combined with ABS for superior support material and is not prone to warping. Applications for HIPS include children’s toys and product casings. 

 

More durable than ABS, nylon filament is now compatible with the latest models from 3D Systems. A high-strength co-polymer material, nylon is a hard composite that has been used for parts in the automotive industry and bearing and fitting fabrication parts without any toxic fumes during the printing process. 

 

Filament Width 

Many commercially available thermoplastic-based printers use 1.75 millimeter filament, but some older models are 3mm. The thinner 1.75mm is more flexible and more controllable, reducing the amount of excess plastic on the final object. Filament is available in spools, moisture-lock cartridges, or individual strands (for the handheld 3Doodler pen), and is melted and fed through the 3D printer extruder as a string during the printing process. Some printers come with either one extruder for one-color prints, or dual extruders that can print two colors at one time. 

 

If you’re printing in bulk, or large objects, you’ll want to purchase your filament in bulk. But if you’re only printing at a hobbyist level, and want to keep tabs on your filament costs, you should consider a printer, like the Cube series, which uses a moisture-lock cartridge. A moisture-lock cartridge enables a printer to detect how much filament is available for a job, eliminating manual mathematical calculations for specific object sizes. When the smart cartridge is loaded, the printer’s built-in settings calculate the filament requirements and alert the user if the supply needs to be replaced. Not all 3D printers can be configured with smart cartridges. Individual filament strands also come in 10" lengths for the smaller handheld 3Doodler printer. One strand is inserted into the 3Doodler at a time and is melted through the single extruder, giving the user a more spontaneous approach in 3D design—consider it a freehand 3D creator. 

 
 
 

Filament Weight 

Thermoplastic filament is measured in weight, not length, despite the fact that it's wrapped in spools. When planning for specific projects, the quantity of the filament is an important measurement that should be calculated properly. Generally, filament weight is measured in kilograms, pounds, and even grams, and spools are available in weights as little as 1/2 a pound). Not every object needs the same amount of filament, however, so there are no standard measurements for the amount of filament that will be needed for specific projects. According to MakerBot, about 400 chess pieces can be printed with a 1kg spool. If you are planning to create a series of similar objects, a gram scale is a good tool to gauge how much filament is required. Some 3D printer LCD menus include a preview option that calculates the cost of material before a job. There are also several downloadable 3D Printer calculators that estimate the weight and the final price of creating an object. A calculator requires the type of material, the filament diameter, and the price per kilogram. One decent online calculator is available from MakerBot

The Build Space

Build Volume

The Build Volume is a measure of volume specifying the width, depth, and height of a three-dimensional object. For those familiar with 3D FX/animation graphics or geometry, the measurement is known as XYZ. More specifically, X is the width of an object, Y is the depth, and Z is the height. When looking for a 3D printer, maximum creation size is one of the most important specs. For example, the 3D Systems CubeX has a maximum size of 9 inches wide by 10.75 inches deep by 9.5 inches high. If your final project exceeds the creation size of your printer, you may want to look at larger printers or commercial options. But the creation size may not be a hindrance—you can always design separate, smaller modules, and piece them together with adhesives after all pieces are completed. Other systems, like the MakerBot Z18, can build objects a 12 inches wide, 12 inches deep, and 18 inches tall.

 
 

Heat Beds

For ABS printing, heat beds or heat build platforms (HBP) prevent the warping that occurs when 3D parts cool at varying temperatures. During the print process, the heat bed keeps the 3D object warm at the base level, while higher layers are printing, for more even cooling. This allows your printed object to remain completely flat on the bed and reduces the effects of warping. The most common warping location occurs at the corners of larger objects during longer print runs. PLA printed objects may suffer from a heated platform. 

 

A high temperature-resistant glass piece with an attached adhesive shield or tape reduces the possibility of warping. The adhesive shield or tape stabilizes the 3D object during the printing process and helps prevent the object from “floating” around the build area. Afina’s series of Borosilicate Glass, sold as separate options to the company's printer line, tolerates rapid cooling because it is less susceptible to thermal stress. Most printers intended for ABS printing, like the MakerBot Replicator 2X, have a built-in HBP. 

 

Automatic Bed Leveling 

Automatic Bed Leveling has become a popular feature with some of the latest models of 3D Printers. For a successful print, the build platform/bed needs to be perfectly level at all points so the final object can be created with precision. The process usually takes less than five minutes to complete and is a necessary step before starting the print job. 

 

Dual Extruders

Dual extruders have started to gain popularity in the desktop 3D printer market. With a single extruder or nozzle, only one color or material can be printed at any time. A dual extruder system like the MakerBot Replicator 2X or the Flashforge Creator series enable two-color printing for diversity and design flexibility, or two-material printing for a more stable support structure. 

 
 

Some 3D printers have triple print-head configurations, allowing three colors to be printed simultaneously. So, even though there are only 18 available filament colors for the 3D Systems CubeX 3D Printer Trio or the 3D Systems CubePro, by combining three colors, you can create almost 5,000 different color options. 

 

Accessories

There are several accessories to consider when purchasing a 3D printer—and some of them can be found at your local hardware or appliance stores. Blue painter’s tape, for instance, is a good adhesive for PLA print jobs and is easily removable. Kapton tape is a high-temperature-resistant polyimide film with silicon adhesive, ideal for ABS jobs on heated plates. 

 

A thin metal spatula is recommended in case the 3D object sticks too firmly to an acrylic build plate. A simple desktop fan can regulate the temperature of the build platform and nozzle during longer PLA-based print runs with larger objects.  

 

Other tools include gate cutters, angled long-nosed pliers, and precision tweezers, which can be helpful when cleaning up the 3D model. Digital calipers and gram scales are great for precise measuring and specific weight requirements. 

Design Phase

Software

Some 3D printers read a 3D-printable file called STL (STereoLithography), which is native to the three-dimensional stereolithography CAD format and is compatible with most 3D modeling programs. Other printers read .cubepro, .cubex and/or .makerbot files, and their included software will convert these files to .stl. A series of intuitive 3D modeling programs is available from 3D Systems. There are also several downloadable applications with excellent 3D printer support such as Rhino, Blender, Pixelogic Zbrush 4R6, 3D Systems and Cubify Design, as well as several other professionally tailored high-end programs such as Autodesk Maya and NewTek LightWave 3D. The latter are programs 3D animation professionals already use, but now come with 3D import, export, and printing support. You can even create 3D objects in Adobe Photoshop. 

 
 

For those not as adept in creating in a three-dimensional layout on a computer, online libraries have pre-assembled collections of multi-categorized objects that may fit your needs. Thingiverse (from MakerBot), Yeggi, Ponoko, and Youmagine are online communities that will help you to get started on 3D printing. They’re great for the beginner, or users experimenting with filament sizes and colors. 

 

3D Scanners

Another option for 3D object creation is the 3D scanner. A 3D scanner is a device with one or more cameras that digitizes a physical object, collects the geometric data, and saves it as an STL file. The MakerBot Digitizer Desktop 3D Scanner has a built-in 1.3MP CMOS camera that digitizes up to an 8 x 8 x 8" object on a rotating disc. The handheld 3D Systems Sense 3D Scanner is an object-recognition tool that uses two front-facing cameras to scan up to a 9.8 x 9.8 x 9.8' object. One camera captures the geometry of the target object, while the second captures the color data for a more detailed representation. 

 

Mobile Apps

A number of 3D applications for mobile app to 3D printing are coming to market in the second half of 2014. These include apps like the free MakerBot Mobile app, which gives you the power to monitor and control your Fifth Generation MakerBot Replicator 3D Printer and access MakerBot files from your mobile device, or apps that turn your smartphone into 3D scanners.  Other apps include 3D printing form the cloud, or the ability to view and share your 3D creations.

Performance

Print Speed

Like traditional printers, no printer will create an object in the blink of an eye. Print speed (measured as millimeters per second) depends on the type of filament that is being used and the amount of detail the final object is intended to have. A complicated object with more angles and edges will slow down a print job. For example, a 3D replica of the Empire State Building with its numerous detailed edges will take a considerably longer printing time than a similar scale model of the World Trade center with its smooth, flat outer walls. ABS filament usually prints more slowly than PLA, because it melts from a plastic to a liquid, where PLA is a solid-based material that needs heavier extrusion. If time is not a consideration and the object has a high amount of detail, a slower print speed adjustment is recommended because the print nozzle’s quick movements can cause vibrations that may affect the detail of your printed object. 

 
0.3 mm Layer Height 0.2 mm Layer Height 0.1 mm Layer Height

Resolution

Printer resolution is the layer thickness on the horizontal X-Y axis (width and depth) and the Z axis (height) and is measured in microns or micrometers. Many commercially available 3D printers have a layer thickness of 100 microns or 0.004", which is about the thickness of a standard piece of paper. The lower the number of microns, the more detail the final object can have, because the extruder is making the least amount of movement during the printing process. Imagine making a model of a chess piece where you have to stack one-inch cubes of paper together. The end result will be blocky, but recognizable. Now imagine making that same model using sheets of paper. It may take longer, but the level of detail will be much higher. Most printers enable users to adjust the layer thickness, like the Afina H480, which has a range of 150-400 microns. 3D Systems has the first commercial models capable of printing at the highest resolution available, a finely grained 70 microns. Both the Cube 3 and the CubePro are also capable of printing at 200–300 microns using different speed settings during the print process. 

Conclusion

Much like the desktop publishing revolution of the 1980s and the desktop video wave of the 1990s, we are now on the ground floor of the desktop 3D printing era. While 3D printers become more affordable and easier to use, a social and cultural shift can now easily and quickly shape new ideas and create a plethora of new opportunities in several industries. Individual hobbyists and creative businesses will be able to share conceptual designs across the globe and turn them into real-world—and real-time—applications. 

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Well written article.  I understand it.

An interesting sequel to this article might include:
-Price range of a whole system to do 3D printing.  Minimum vs. optimum.
-Minimum/Optimum computer capability. I suspect my computer running Vista will not cut it.
-I wonder if non-plastic reinforcing could be incorporated in an object for additional strength.

Thank you for writing the article.

Good