The Basics

3D printing has been around since the late 80s, but over the past eight years, the technology has become dramatically more affordable and widely used.  There are a variety of different 3D printing processes, but e-NABLE mainly uses a process called Fused Filament Fabrication or Fused Deposition Modeling (FFF or FDM– the two are synonymous), which is the most popular and lowest cost of the processes.  FFF/FDM printers operate by moving a very small nozzle around in two directions to extrude or draw a picture using a thin thread of molten plastic.  Once the printer finishes drawing one picture (which we call a layer), the platform on which it is drawing moves down a small step, making space for a new picture.  By drawing pictures in plastic, one on top of the previous, the printer can produce 3D objects.  Most printers print in a material called PLA (polylactic acid), which is a non-toxic bioplastic often derived form corn and is the same material that compostable cutlery and coffee cup lids are often made from.  PLA is fed into the printer in the form of a long, thin filament of plastic (typically 1.75mm in diameter) that comes wound in a spool.   There are many other materials that FFF/FDM printers can print in, but e-NABLE hands are

Choosing a 3D Printer

There are a nearly overwhelming number of different desktop 3D printers out there, each with slightly different capabilities and features aimed at different users and different applications.  For those who are looking to get into 3D printing, commercially-produced machines are much easier to use and often don’t require assembly.  For a more hands-on education in how 3D printers work, open source kit-based printers are a rewarding (but time-intensive) way to learn about 3D printing.  e-NABLE volunteers operate a wide range of 3D printers that can typically be purchased for between $500 and $2500.  We hold our fabricators to a high standard when it comes to print quality as the function, safety, and durability of e-NABLE hands depend on it.

Several groups have produced guides to help new users pick a printer:

• Many e-NABLE volunteers compare notes on printers in the e-NABLE forums.  Feel free to join and ask members what they use and why they prefer it over other printers.
• Make Magazine runs an annual 3D Printer Shoot Out to compare top desktop printers.  The 2015 results are summarized here and a the full-length reviews of all 26 printers are available here.
• 3DHubs produced a 2015 guide to the best 3D printers based on data from their network of over ten thousand printers.  They also release monthly trend reports that are a wonderful summary of printers and print quality.
• e-NABLE volunteer Joe Cross put together a table of reviews of the machines that e-NABLE volunteers are using that is available here.

When looking for a 3D printer, consider the following:

• Reliability:  3D printers often require some maintenance, so look for machines with positive reviews and few reports of longevity problems.
• Supporting Documentation:  3D printing is still a technical and complex process and having a good user manual to guide you through the process can be extremely helpful.
• Online User Community:  Many printer manufacturers host online forums where users compare notes and tips on using their machines.  These user communities are a great place to get oriented when learning about 3D printing and other users can often answer a wide variety of questions.
• Dimensional Accuracy:  This is very important when printing hands for e-NABLE as their function as mechanical devices depends on numerous parts fitting together properly.
• Surface Finish:  Typically this indicates a poor tuning between software and the hardware and can be fixed, but is a bad sign for commercially-produced printers.
• Material Capabilities:  Features like a heated build platform expand a printer’s capabilities to print in different materials.  Machines without heated build platforms typically print only with PLA, the most common material used in e-NABLE hands, and flexible materials like Ninjaflex and Filaflex.  With a heated build head, printers can print in Nylon and ABS as well as other more experimental materials.
• Cooling:  A fan directed at the exit of the nozzle helps cool PLA as it is being printed, helping with overhangs and bridges (un-supported horizontal spans) and resolving small features.
• LCD Interface:  Though not strictly necessary, an LCD interface can be a big boost to usability.