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How many popular types of 3d printers?
There is a diverse and rapidly expanding field of 3D printers—so big, in fact, that to give all of the available printers ample coverage, it would take a book just on that alone. We can’t cover everything here, but what we can do is to provide a brief survey of some of the most popular printers available right now. These printers can be roughly categorized into four main groups: the RepRaps, the Box Bots, RepStraps, and the Upstarts. All of the printers discussed here can be purchased for $2,000 or less in a kit form or sourced from individual parts and suppliers. Each of these 3D printer designs has been proven through extensive testing and development, and if available through a retailer, the company has proven to be reliable and consistent. If you choose to build a 3D printer yourself instead of buying a preassembled one, you will find that it is generally not that much more difficult than building your own personal computer—although being handy with the business end of a wrench is helpful.
The RepRap, developed by Dr. Adrian Bowyer at Bath University, is the 3D printer that started it all in 2007. The first RepRap (short for “replicating rapid- prototyper”) named Darwin, was a 3D printer capable (at least in theory) of reproducing itself by printing the parts needed to make a new one. By designing a working 3D printer using 3D printed parts (albeit parts printed on an expensive industrial machine in the beginning) along with off-the-shelf hardware, the RepRap broke through the price barrier of industrial 3D printers. With the Darwin, RepRap started the DIY 3D printer revolution that has been evolving ever since.
Darwin was eventually replaced by a second-generation RepRap named Mendel, which was further refined in 2010 by Josef Prusa to require fewer parts, both printed and hardware, while retaining most of the functionality. This new stripped-down design has been called the Model T of 3D printers and for good reason: it operates under the mantra of function over form and it can be very affordable. One of the highest quality Prusa Mendel kits available on the market today, shown in Figure 1-7, is produced by the Ohio-based company MakerGear (www.makergear.com).
Figure 1-7. MakerGear Prusa Mendel
The Prusa Mendel is a low-cost, low part-count 3D printer that has a useable build volume of 200mm × 200mm × 110mm (roughly 8" × 8" × 4.5") with a frame built using a combination of printed parts, threaded rod, and other hardware. Prusa Mendels use two motors for the z-axis wired in parallel to reduce the amount of manufactured parts like pulleys and timing belts. MakerGear improves on the basic design by using stainless-steel hardware, self- aligning bronze bushings for linear motion, a heated printbed, and a laser-cut sled for the y-axis.
If you are more interested in saving a few pennies than getting all the bells and whistles, the Prusa Mendel can be one of the least expensive printers to obtain—if you source all of your own hardware and have a friend or hackerspace nearby that can print the plastic components for you. For more information, head over to the RepRap wiki at http://reprap.org. These printers take significantly more time than others to build and get properly calibrated, especially if you are sourcing all of your own parts; however, there is a large group of Prusa Mendel owners that are willing to share their knowledge, advice, and improvements for the design.
The following are some of the highlights of the Prusa Mendel:
Mid-range build volume
With some work, can obtain quick print speeds
Very affordable if sourcing your own parts
Takes quite a lot of time to build and properly dial in
The Huxley design is the smaller, more portable brother of the RepRap Mendel. Currently, the Huxley design of choice, shown in Figure 1-8, is made by RepRapPro, Ltd. (http://reprappro.com), lead by RepRap’s primogenitor, Dr. Adrian Bowyer, and eMAKER’s Jean-Marc Giacalone.
Figure 1-8. eMAKER Huxley (courtesy Johannes Heberlein, 2011)
The Huxley is a little cheaper than the Prusa Mendel, depending on whether you source it yourself or if you buy a kit, although size and portability is more important to this design than price. The Huxley features a modest, build volume of 140mm × 140mm × 110mm (about 5.5" × 5.5" × 4.5")—in one of the smallest 3D printers in overall size. Through a combination of linear bearings on the x- and y-axes and fine pitch threaded rod on the z-axis, the Huxley is capable of some astonishingly detailed prints.
Because of the smaller size of the printer, the filament driver portion of the extruder that normally rides on the x-axis carriage has to be separated from the hot end and relocated to the frame of the printer. To link the filament driver and the hot end, the designers use something called a Bowden cable, basically a plastic tube that connects the filament driver to the smaller hot end on the x-axis carriage. This can be seen as a good or bad thing, depending on your point of view. Either this design offloads much of the bulk of the extruder from the x- axis, allowing it to move more quickly and with greater accuracy, or it might present problems with the actual plastic extrusion because of the added complexity of this arrangement and the increased friction of the tube, causing prints that look stringy in appearance.
The following are some of the highlights of the RepRap Huxley:
One of the smallest available printers with a modest build volume
More accurate and reliable linear motion system
Bowden cable extruder is either a pro or con
Takes almost as long to build and set up as a Prusa Mendel
Where the RepRaps are unified by their basic design premise and a loose affiliation with the reprap.org web site, Box Bots can only be easily grouped together because of their use of plywood frames, built from bolted-together, precision, laser-cut panels. Because of this, and unlike the RepRap printers, a 3D printer is not needed to produce one of these kits, making them easier and faster to distribute. Additionally, the printer’s assembly is often much easier than the RepRaps’, making the printer more precise and easier to calibrate. This section looks at three different printers made by three different companies that are attempting to make 3D printers for the masses.
MakerBot Industries (http://store.makerbot.com) was the first post- RepRap 3D printer to introduce an easy-to-assemble, low-cost 3D printer kit with their Cupcake CNC in 2009, which, while inspired by the RepRap Darwin, used a laser-cut plywood frame and structural components along with off-the- shelf hardware. MakerBot’s second-generation Thing-O-Matic, shown in Figure 1-9, featured numerous advancements in their linear motion control and extruder technology.
Figure 1-9. MakerBot Thing-O-Matic (foreground, courtesy Tony Buser, 2011)
The Thing-O-Matic has one of the smallest build volumes at 120mm x 120mm x 115mm (or 4.7" × 4.7" × 4.5"). MakerBot’s recently introduced third- generation printer, called the Replicator, will feature a larger 225mm × 145mm × 150mm build volume (roughly 8.9" × 5.7" × 5.9"). Where the Cupcake and Thing-O-Matic were offered as kits that could be built in about a weekend, the Replicator will be the first of the Box Bots to come fully assembled directly from the manufacturer as standard, with a heated build platform. While it has the potential of being the easiest 3D printer to set up and get printing, the cost of assembly places the Replicator at the top of our $2,000 price range.
Not only does the Replicator ship preassembled, it is also the only low-cost 3D printer that comes with a standard option for dual extruders. This means that it is now possible to print using two different colors of filament or, while still experimental, to print very intricate parts or unsupported overhangs using a water-soluble support material in addition to the standard plastic filament. While other printers have had dual extruders on their radar for some time now (and some even have the electronics to do this), the MakerBot Replicator is the first and only printer to the market with this capability as standard at or below our price range.
With the Thing-O-Matic discontinued and the Replicator only just now shipping, the following summary for the MakerBot is a little speculative:
Prebuilt at the factory, giving it a fast out-of-box to printing time
Little to no initial calibration, although long-term reliability is unknown
Dual extruder option for two-color or support printing
Most expensive printer in our survey, and not as gratifying as building it yourself
MakerGear Mosaic M1
In addition to the Prusa Mendel kit pictured earlier, MakerGear also produces their easy to use and set up Box Bot, the Mosaic, available at www.makergear.com/products/m-s... and shown in Figure 1-10.
Figure 1-10. MakerGear Mosaic M1
Even though the Mosaic is not a box in the strictest sense, it uses laser-cut plywood as a structural element while featuring an interesting take on the 3D printer formula by having the printbed move on both the y-and z-axes, with the z-axis lowering as the object is printed. Its build volume sits nearer to the smaller end of the spectrum at 127mm × 127mm × 127mm (exactly 5" × 5" ×5") although it includes a heated printbed as standard. What makes the Mosaic unique, besides its unusual form, is the use of precision-machined linear guides and rails for the x-and y-axes, and Teflon-coated lead screws and antibacklash nuts specifically designed for CNC machines. This creates a machine that is reasonably easy to assemble and calibrate, and fairly precise at the same time.
To make the assembly of the Mosaic as painless as possible while still catering to us DIYers, MakerGear has preassembled some components of the kit and have also prewired all of the electronics so that you can quickly assemble the printer, connect the electronics, and get to printing—all in a single afternoon. Compared to some of the other 3D printers in this chapter, calibration is reasonably painless and it holds its calibration longer, requiring less long-term maintenance—and all of this in a printer that retails for about half of the newest MakerBot and is second only to the Huxley in its small size.
The following are some of the highlights of the MakerGear Mosaic:
Fastest out-of-box to printing time of the kit-based printers
Unique precision hardware for painless calibration and long- term reliability
One of the more accurate linear motion systems
Most affordable Box Bot kit
Even though Ultimaker (https://shop.ultimaker.com) has not been around as long as MakerBot and MakerGear, the company makes one of the fastest DIY 3D printers on the market, shown in Figure 1-11.
Figure 1-11. Ultimaker (courtesy Dave Durant, 2011)
At 210mm × 210mm × 220mm (or 8.25" × 8.25" × 8.5") the Ultimaker has the largest build area of any of the 3D printers covered in this chapter, although a heated printbed is not included in the design. Unique to this Box Bot is a flying gantry-based thermal printhead that can move at amazing speeds on both the x- and y-axes. To limit the weight of the printhead, the Ultimaker also uses a Bowden cable to decouple the filament pusher from the hot end, resulting in
some of the same problems that the RepRap Huxley suffer from, namely stringy prints where the filament doesn’t retract quickly enough when the printhead moves from one location to the next. Mechanically, the Ultimaker features a veritable plethora of linear bearings on every axis, which lends to this printer’s fast speeds and overall reliability.
While the Ultimaker’s feat of engineering provides for some great accuracy, it comes at price—it is one of the most expensive 3D printers on the market, second only to the MakerBot Replicator—and the kit is a little harder to assemble than the others, as well. Once assembled, though, the Ultimaker makes for a very reliable 3D printer with minimal maintenance over the long term. The prints that Ultimaker owners have shared online are simply awe-inspiring, albeit most of these higher-quality prints use an optional, closed-source printer application that costs about $200; even so, the Ultimaker has a devoted following among its community of owners.
Highlights of the Ultimaker 3D printer include the following:
Best print speed and highest precision of any kit printer with excellent print quality
Largest available print area in a relatively small footprint
Lack of an option for heated printbed limits the materials or kinds of prints
Cost and complexity limit this printer to the dedicated- enthusiast level
When the RepRap was just getting started, the printed components of the Darwin were printed using expensive, industrial 3D printers—limiting the early adoption of personal 3D printers. To get around this chicken-and-egg problem, the community developed the RepStrap—a mashed-up name for a bootstrapped RepRap. These machines were simple CNCs made in home workshops, coupled with some form of a thermoplastic extruder that was capable of printing the parts to make a RepRap printer.
While many RepStraps have come and gone, the whiteAnt CNC, shown in Figure 1-12 and featured in the book Printing in Plastic by Patrick Hood-Daniel and James Floyd Kelly (Apress, 2011), is the only design, currently in development, with plans that are easily accessible and has hardware that is available.
Figure 1-12. whiteAnt CNC (courtesy James Floyd Kelly and Patrick Hood-Daniel, 2011)
The RepStraps are a tinkerer’s wildest dream. With little more than a home woodshop, some base materials like plywood and simple hardware, some electronics and motors that you might have lying around, as well as a few open weekends, and you’re set to build one of these 3D printers on your own at a potential savings. The whiteAnt (http://buildyourcnc.com) design has a build area of 160mm × 190mm × 125mm (roughly 6.25" × 7.5" × 5"), although
there is little reason why this couldn’t be modified to fill any need you might have. The real attraction of this design is that it’s made for someone who values the journey even more than the destination.
Some of the highlights of the whiteAnt CNC include the following:
Very DIY-friendly design allows for endless customization
Provides a good excuse to spend hours in the woodshop on weekends
Middle-of-the-pack build volume, but easily expandable
Takes the most amount of time to calibrate and get up and running
With all the development that has ramped up in the world of personal 3D printers, it wouldn’t be fair to exclude some of the newest designs that are gathering steam as I write this chapter. This section affectionately calls these designs the “upstarts” because they offer a lot of promise; but only time will tell how lasting their designs hold up in the end.
MendelMax and AO-100
Where the RepRap printers generally use threaded rods for the structural frame, making the printer harder to build and properly calibrate, a new breed of 3D printers are turning to square, aluminum extrusions to replace the threaded rod. These printers include the new AO-100 from Aleph Objects (http://alephobjects.com/AO_100.html), shown in Figure 1-13, and the MendelMax designed by Maxbots (http://mendelmax.com).
Figure 1-13. Aleph Objects AO-100 (courtesy Aleph Objects, Inc., 2012)
These aluminum extrusions measure 20mm², with lengths cut to order from the manufacturer. They feature T-slots that run down the length of the extrusion, allowing for special nuts that fit into these slots that parts can be bolted to. These extrusions are often used in structural machine components, providing the printer with much greater structural rigidity, and generally making the printer easier to assemble. While this new material adds anywhere from $100 to $200 to the cost of a standard Prusa Mendel, these printers offer increased printing precision and faster print speeds. Print volumes vary, with the AO-100 coming preassembled with a build area of 200mm × 190mm × 100mm. The MendelMax is available as a kit with a maximum print area of 250mm × 250mm × 200mm. The AO-100 is one of the easier printers to set up and get printing because it ships preassembled. The MendelMax still caters to the tinkerers that enjoy the added challenges that come with the larger print volumes; it is available in either kit form or needs to be self-sourced.
Some of the highlights of the extrusion-frame printers include the following:
Greater printbed sizes than the standard Prusa Mendel are possible
Theoretically more precise prints from a more rigid and symmetrical frame
Aluminum extrusion frames is more expensive than a standard Prusa Mendel
Quicker assembly than a Prusa Mendel, with prebuilt versions available
RepRap Wallace and Printrbot
One of the defining traits of the RepRap and Box Bot printers is the large angular or boxy frame that supports the three separate axes. The RepRap Wallace (http://reprap.org/wiki/Wallace), shown in Figure 1-14, and the Printrbot (http://printrbot.com/shop/printrbot) are two up-and-coming printers that fundamentally redefine what a 3D printer looks like.
Figure 1-14. RepRap Wallace (courtesy Whosawhatsis, 2012)
What makes these 3D printers so unique are their pseudo-frameless design and extremely low part-count. By using two z-axis motors like the Prusa Mendel—except inverting the placement of these motors, placing them at the bottom of the printer, and attaching the y-axis smooth rods to the printbed platform—there became no real need for the trapezoidal or box-like frame of other printers. The drawback to this design is that without the added support, these printers need to run much more slowly than other printers to maintain reasonable print quality. The entry-level Printrbot comes with a heated printbed for a build volume of about 150mm × 150mm × 150mm (or 6" × 6" × 6"), while the standard RepRap Wallace design fits the Prusa Mendel heated printbed with a volume of 200mm × 200mm × 200mm (8" × 8" × 8"), although this latter design is parametric and can be changed to create other sizes of printers, both large and small. Where the Printrbot is sold as a kit, parts for the Wallace need to be purchased from various suppliers; and the printed parts will need to be made by a friend with another printer. If the promise of these designs holds up though, we are looking at the new crop of low-cost 3D printers for the masses, which might put 3D printers in kitchens everywhere.
While still somewhat speculative, the following are the highlights for these frameless printers:
Extremely efficient design makes for a very low-cost 3D printer kit
Easily hackable designs allow for a variety of shapes and sizes low part-count means that these printers can be built very quickly
At this point, a somewhat untested and unproven design
Info from book: Practical 3D Printers_ The Science and Art of 3D Printing