From EduTechWiki - Reading time: 25 min
Most parts of this piece have been written in 2011 and 2012 and some may need updating.
A Fab Lab or fablab (fabrication laboratory) is a small-scale workshop with computer controlled tools with the aim to make "almost anything". (Wikipedia).
Fab labs are a disruptive technology. In the same way that micro computers changed computing, desktop fabbers (fab lab machines) may change manufacturing, i.e. people can produce things at home or within small organizations.
Fablabs are typically open to the public and should have a charter. Other types of collaborative workshops for making are maker spaces, hacker spaces, tech shops, fac labs, etc. A space with a lone 3D printer should not be called a fablab.
Fab labs and 3D printers in particular will have a certain impact on education including computer-supported educational technology. Examples of educational domains and applications are design teaching (in engineering or design schools), producing constructionist learning objects (manipulatives that may or may not be augmented with computer technology), and creation of replicas or augmented objects for museum learning.
See also:
Fab labs can have different aims, e.g. the include rapid prototyping of industrial products or low cost and on-demand manufacturing from "open source designs" for both hobbyist and serious use. Both purposes include an idea of empowering individuals to create devices that are adapted to specific needs. Fab labs also can be part of Do-It-Yourself (DIY) communities, cultures and projects. (Kuznetsov, 2010)
The Fab@Home project emphasizes freedom of design and innovation of a Solid Freeform Fabrication system:
In a similar way IFTF, in the Future of Making Map argues:
Hands-on future is a word play that summarized the idea that is now spreading on the Internet and in venues such as the LIFT France '09 conference. According to Laurent Haug,
What happened in the software industry - young guys waking up with an idea, ending up changing the world from their sofa like it happened with Google, Amazon, Facebook, etc. - is now happening in the tangible world. Things like Arduino are enabling hackers and creators all around the globe, and what was possible with software (easily assemble code to create new applications) is now possible with objects. The conference program was centered around three main topics:
The Fab Lab concept emerged at MIT under the direction of N. Gershenfeld. It included a laser cutter, a miniature milling machine and jigsaw cutting machine. At the same time, people started thinking about creating cheap 3D printers.
The Fab Lab movement also is anchored in ecological thinking. “Think of RepRap as a China on your desktop” (Chris di Bona). Typical materials used in desktop fabrication are not much polluting and there is no transportation cost. The technology will also allow to produce cheap goods that are locally adapted. Finaly, designs can be shared for free, which means that "fab labs" rely on open content, both for the design of the tools and the designs that these tools then can "print".
A possible future was described by Vilbrandt et al (2008) as Universal Desktop Fabrication. “Advances in digital design and fabrication technologies are leading toward single fabrication systems capable of producing almost any complete functional object. We are proposing a new paradigm for manufacturing, which we call Universal Desktop Fabrication (UDF), and a framework for its development. UDF will be a coherent system of volumetric digital design software able to handle infinite complexity at any spatial resolution and compact, automated, multi-material digital fabrication hardware. This system aims to be inexpensive, simple, safe and intuitive to operate, open to user modification and experimentation, and capable of rapidly manufacturing almost any arbitrary, complete, high-quality, functional object. Through the broad accessibility and generality of digital technology, UDF will enable vastly more individuals to become innovators of technology, and will catalyze a shift from specialized mass production and global transportation of products to personal customization and point-of-use manufacturing. Likewise, the inherent accuracy and speed of digital computation will allow processes that significantly surpass the practical complexity of the current design and manufacturing systems. This transformation of manufacturing will allow for entirely new classes of human-made, peer-produced, micro-engineered objects, resulting in more dynamic and natural interactions with the world.” (Abstract, retrieved 17:30, 25 June 2009 (UTC)).
In October 2008, Evan Malone, the principal designer and implementor of Fab@Home, posted a (draft) Functional Block Diagram for FutureFab System at NextFab and that is shown below.

This diagram shows the complexity of software and hardware constraints interaction. Current fabbers can't produce "anything", but near future systems will be able to integrate both solid freeform fabrication (printing 3D objects) and electronic components
An excellent source for the early history of 3-D models is Lipson et al, 2004). According to this paper, “Physical models of machines have played an important role in the history of engineering for teaching, modeling, and exploring mechanical concepts. Many of these models have been replaced by computational representations, but new rapid-prototyping technology allows reintroduction of physical models as an intuitive way to demonstrate mechanical concepts” (Lipson et al, 2004:1032).
Here are a few milestones (that should be completed):
There exist several popular fab lab technologies, some of which are described below in more details. Most fall in the category of solid freeform fabrication tools and that include:
A fabber (or digital fabricator) refers to a "factory in box" (i.e. one of the above tools) that can create things automatically from digital data. The Digital Fabrication Portal distinguishes three fundamental kinds of fabbers, according to the way they operate on their raw material:

As of May 2009, there seemed to be three kinds of fab labs
As of April 2019, there is more diversity:
We found it quite interesting that when wrote the version of this piece in 2009, the MIT and the Waag fab lab did not include 3D-printers in the description of their setup. That probably meant that these two communities lived on two different "planets". However, as of 2011, the "official" list of fab lab engines include a 3D printer.
“Freeform Fabrication is a collection of manufacturing technologies with which parts can be created without the need for part-specific tooling. A computerized model of the part is designed. It is sliced computationally, and layer information is sent to a fabricator that reproduces the layer in a real material” (Laboratory of Freeform Fabrication, UTexas, retrieved 17:25, 24 June 2009 (UTC)). CreatItReal shows an animation of this principle. Typical commercial free form fabricators range between 20'000 and 300'000 $US although low-end 3D printers start at $5000 (June 2009). Open source kits are much cheaper if self-assembled (see 3D printing)

Low End Solid Freeform Fabrication tools, also called rapid prototype machines are usually a kind of 3D printers. “3D printing is a unique form of fabrication that is related to traditional rapid prototyping technology. A three dimensional object is created by layering and connecting successive cross sections of material. 3D printers are generally faster, more affordable and easier to use than other additive fabrication technologies. While prototyping dominates current uses, 3D printers offers tremendous potential for retail consumer uses.” (Wikipedia, retrieved 17:25, 24 June 2009 (UTC)).
Currently, low-end commercial 3D prototypers are becoming affordable for individuals who want to "play" or schools. On oct 2011, the cheapest 3D printer we found was at $2700 from Up! Open source systems cost much less (not counting assembly time) and assembled versions cost about $4000.
According to Wikipedia (retrieved 17:25, 24 June 2009), “Prototypes made by low-end commercial machines cost around US$2 per cubic centimeter to fabricate. The RepRap Project is on track to produce a 3D prototyping machine and free and open source accompanying software that costs about US$400 to build and which can fabricate objects at a cost of about US$0.02 per cubic centimeter.”
There exist various kinds of 3D printers, e.g. Inkjet-like where layers of powder (e.g. plaster, corn starch or resins) are selectively bonded or photopolymer machines that fix liquids with an UV flood lamp.
A similar more complex procedure is called fused deposition modeling (FDM) (Montaro, 2002) and is described more precisely by Lipson et al. (2004:1030): “The process creates a sequence of thermoplastic layers from a filament wound coil that is heated and extruded through a nozzle. The trajectory of the nozzle is derived from the triangle mesh, so as to raster scan and fill solid volumes. In order to create functioning mechanisms, a second, soluble release material is placed in the gaps between the movable parts.”
This article present 3D printing at its beginning in the early 2000's. Also see 3D printing for a more up-to-date article.

Very low-cost non-proprietary 3D printers are often referred to as Fabbers (although the term includes other technologies, including high-end ones). There exist several projects with a high profile in the "web 2.0 sphere". Most printers use a "hot gun" plastic extruder, but other techniques are emerging, e.g. sugar sintering in the CandyFab project.
The Fab@Home project (retrieved June 2009) “is a project dedicated to making and using fabbers - machines that can make almost anything, right on your desktop. [...] Fabbers (a.k.a. 3D printers or rapid prototyping machines) are a relatively new form of manufacturing that builds 3D objects by carefully depositing materials drop by drop, layer by layer. With the right set of materials and a geometric blueprint, you can fabricate complex objects that would normally take special resources, tools and skills if produced using conventional manufacturing techniques. A fabber can allow you to explore new designs, email physical objects to other fabber owners, and most importantly - set your ideas free. Just as MP3s, iPods and the Internet have freed musical talent, we hope that blueprints and fabbers will democratize innovation.”. Fab@Home was conceived by Hod Lipson of Cornell University and designed and implemented by Evan Malone. Current development includes more people.

RepRap is another well known project. “RepRap is short for Replicating Rapid-prototyper. It is the practical self-copying 3D printer shown on the right - a self-replicating machine. This 3D printer builds the parts up in layers of plastic. This technology already exists, but the cheapest commercial machine would cost you about €30,000. And it isn't even designed so that it can make itself. So what the RepRap team are doing is to develop and to give away the designs for a much cheaper machine with the novel capability of being able to self-copy (material costs are about €500). That way it's accessible to small communities in the developing world as well as individuals in the developed world. Following the principles of the Free Software Movement we are distributing the RepRap machine at no cost to everyone under the GNU General Public Licence. So, if you have a RepRap machine, you can use it to make another and give that one to a friend...” (What is RepRap?, retrieved 17:25, 24 June 2009 (UTC)).
This RepRap 3D printer builds the parts up in layers of plastic with the help of a custom-made Thermoplast Extruder. Version 2 “takes a 3mm diameter filament of a polymer (the single white rod coming into the picture from the top, not to be confused with the pair of white 12V supply wires), forces it down a heated barrel, and then extrudes it as a melt out of a fine nozzle. The resulting thin stream is laid down in layers to form the parts that RepRap makes. The extruder should work up to a temperature of 250o Celsius”. It works with ABS (Lego-like plastic) and polylactic acid. (Thermoplast Extruder Version 2.0, retrieved 17:30, 25 June 2009 (UTC)). In the UK, a RepRap assembly kit with everything included, is available as RapMan (2009/2010).
The next version of RepRap (RepRap Version 2.0 "Mendel") had ambitious plans: “will have multiple write heads for working with a wide range of materials in a single reprapped object, and will have the ability to embed three-dimensional electrical circuitry inside mechanical parts. Mendel is still very much in the early stages of development, but the build instructions are themselves under construction at that link.”

The CandyFab project is a 3D freeform fabrication project that works with sintering of sugar and other low-melting point materials. This project is different from Fab@Home and RepRap in two ways. The fabricator can print a much larger printable volume but with a lower resolution and you may eat the product. The creators argue that “Sugar is a particularly good medium because it's easy to obtain, low in cost, kid friendly, water soluble, non-hazardous, non-toxic, non-intimidating, rigid despite having a low melting point, and may be suitable for making objects for lost sugar (like lost wax) investment casting. We also think that it may also be possible to make interesting food with this technology.” (Sneak preview: The Evil Mad Scientist 3D Printer Project, retrieved 17:30, 25 June 2009 (UTC)).
One interesting application of the CandyFab would be to create 3D models of statistical data to be shown in presentations (e.g. a workshop or a thesis defense). After discussion, participants could eat the research results and further discuss data quality and distribution.
W.H. Oskay summarizes the procedure as follows: “When the first layer is started, there is a bed of granulated sugar. The heat gun locally melts the top surface of the bed in one point, melting the sugar at that point. The heat gun then moves to the next point, melting the sugar there. If this is done in a number of points in a row, it begins to fill in a line of melted sugar [...]. The sugar only stays molten for about 15-30 seconds after the heat gun is removed from a point. If a second line of melted sugar is added next to the first, you can begin to fill in an area with a thin layer of fused sugar. Let's suppose that you were making a cylinder-- then the first layer would just be a circle. The depth of the melt layer is controlled by the temperature, air flow rate, and hold time at each pixel location. After the first layer is finished, the bed is lowered slightly-- by an amount equal to the melt depth-- and a fresh layer of sugar is added to the top, such that the new top surface is at the same place where the original surface was. To make the next step in the cylinder, a new circle is drawn in the sugar on this layer. For each point in the circle, as the sugar in the top layer melts, it fuses to the corresponding point in the hardened sugar circle below. If we were to let the model cool and take it out of the machine at this point, you would have a solid thin disk, twice the thickness of the melt layer.”
Until recently, Solid Freeform fabbers had to be assembled by the end-user using open designs and low-level parts, i.e. many many days of bricolage. However, some fabbers now can be bought commercially as easy kits or fully assembled. E.g. in June 2009, the NextFab Store sold kits for about $3000 and assembled Fab@Homes for about $4000. Bits from Byte sold a (unassembled) RepRap kit (Version 3 - RapMan) for about £750. Read the RapMan entry for additional information. On June 2009, Cupcake from MakerBot Industries sold for £750 (unassembled). Malone and Lipson (2007) published an interesting breakdown of the cost of the model 1 fab@home 3D printer. Part costs were about $2300 USD plus about 18 hours of assembly work.

Within just three years, 3D printing became increasingly popular and as of 2011, several end-user machines are available. Prices started dropping a lot, i.e. commercial kits can be had for $1000 or less as you can see in the 3D printing article.
There also exists a low-cost Laminated Object Manufacturing engines that works with paper. Such a printer can use standard sheets of printer paper and will deposits in a pattern determined by the design. Another sheet of paper is added, and a blade then cuts away the excess paper. Such systems however, were too expensive (e.g. the Matrix 3D may sell for about $20'000).

According to Bart Bakker (oral communication, dec 2011), Laser cutters are the most popular tools in Netherland's fablabs. Laser cutters can't be used in closed rooms (i.e. needing air filtering). They also are expensive, although some exciting developments are out there, in particular LAOS, i.e. an open source replacement board and software that could be use to drive cheap chinese hardware.
Plasma cutters come in various sizes and are available from $3000.
According to Wikipedia, water jets can cut with a with of about 1mm and can cut materials such as rubber, foam, plastics, composites, stone, glass, tile, metals, food, paper and much more. Also, water jets can cut material without much harming or changing the materials' structures since there is no heat. I also can be considered a green technology, since it doesn't produce harmful waste. Water and abrasives can be recycled.

Various technology can be combined into 3-axis CNC robots. As an example: “micRo is a unique system which can be used for both additive (printing) and subtractive (milling, cutting) fabrication. It is a precise, modular tool which allows you to create complex objects out of wood, metal, plastic and more”

“In the Selective Laser Sintering (SLS) process, three-dimensional parts are created by fusing (or sintering) powdered thermoplastic materials with the heat from an infrared laser beam.” (Selective Laser Sintering (SLS), SLS Prototype, retrieved 17:25, 24 June 2009 (UTC)).
This technology if fairly complex and expensive compared to low-end 3D printers that extrude plastic. However, Markus Kayser in his SolarSinter demoed a cool bricolage version that sinters sand with solar energy. Also, commercial laser sintering printers should probably soon be available for less than 10K. (dec/2011).
Stereolithography (or photopolymerization) “is a common rapid manufacturing and rapid prototyping technology for producing parts with high accuracy and good surface finish. A device that performs stereolithography is called an SLA or Stereolithography Apparatus.” (Wikipedia, retrieved 17:25, 24 June 2009 (UTC)).
SLA is too expensive for fab labs (between $100,000 and $400,000)
A milling machine (fr. "fraiseuse") is a machine tool used for the shaping of metal and other solid materials. It uses rotating cutters to cut stuff from a workpiece. In more sophisticated milling machines, both the cutters and the workpiece can be rotated in three axis.
See also:

A whole variety of hobby mills are now available and work with softer materials, e.g. the Roland iModela iM-01 Hobby Mill. According to the product announcement page, retrieved 14:33, 7 December 2011 (CET), the iModela is an inexpensive (about $1000), easy-to-use desktop device that mills wax, foam, balsa wood and plastic materials commonly used in craft and hobby projects. The iCreate web site includes a few sample designs plus other support materials. This model can read IGES, DXF and STL and only works with Windows.
A computer-controlled embroidery machine allows to print out complex designs, e.g. embroidery.
An alternative to designing objects is to scan them. Rotating 3D scanners can be bought for about $3000, but hand-held Laser 3D scanning costs next to nothing (see the links section below for pointers).
See also: Embedded systems building blocks, often that kind of hardware is specially made for education.
Arduino “is an open-source electronics prototyping platform based on flexible, easy-to-use hardware and software. It's intended for artists, designers, hobbyists, and anyone interested in creating interactive objects or environments.
Arduino can sense the environment by receiving input from a variety of sensors and can affect its surroundings by controlling lights, motors, and other actuators. The microcontroller on the board is programmed using the Arduino programming language (based on Wiring) and the Arduino development environment (based on Processing). Arduino projects can be stand-alone or they can communicate with software on running on a computer (e.g. Flash, Processing, MaxMSP).” (Arduino Home Page, retrieved 17:25, 24 June 2009 (UTC)).
OpenMoko is is a project dedicated to delivering mobile phones with an open source software stack. Openmoko is currently (June 2009) selling the Neo FreeRunner phone to advanced users and will start selling it to the general public as soon as the software is more developed.
“The Openmoko stack, which includes a full X server, allows users and developers to transform mobile hardware platforms into unique products. Our license gives developers and users freedom to cosmetically customize their device or radically remix it; change the wallpaper or rebuild the entire house! It grants them the freedom, for example, to transform a phone into a medical device or point of sale device or the freedom to simply install their own favorite software. Beyond freeing the software on our devices we have also released our CAD files. And at LinuxWorld 2008, we announced the release of the schematics for our products.” (Introduction, retrieved 17:30, 25 June 2009 (UTC)).
The Make Controller Kit sponsored by Make magazine, is an open source hardware solution for hobbyists and professionals to create interactive applications. It supports desktop interfaces via a variety of languages such as Max/MSP, Flash, Processing, Java, Python, Ruby, or anything that supports Open Sound Control (OSC).
See
See 3D printing

Laser and plasma cutters
Water jets
CNC mills
CNC shopbots
Selective Laster Sintering (SLS)
Stereolithography (SLA)
In order to avoid hassles with repairs and an such, it is probably a good idea to buy in your own country. E.g. in Switzerland, there is the dshop (an Arduino/OpenMoko vendor)
Make Controller Kit online sales at Making Things.com
(Closely or loosely related to fablabs)
There exist a number of solutions, i.e. several organizations do have buses that include fablab.
See also digital design and fabrication bibliography and fab labs in education
Thanx to Nicolas Nova for inviting Daniel K. Schneider to LIFT France '09 which gave me the impulse for writing a first version of this piece and to explore various sub topics in more depth.