Image from Bernd Helfert
Ubiquitous class of manufacturing machine that can be programmed to build virtually any normal-matter product from simple chemical feedstock. Throughout history, and across myriad cultures, there have been a plethora of names for this technology; some acting as direct synonyms whilst others refer to specific variants. Briefly, the most common are: fabricator (fab/autofab), nanofactory (nanofac/autofac), nanoforge (forge), universal assembler, Genie, Santa Claus Machine, and Drexler. They have been the backbone of Terragen industry for nearly ten thousand years, from household units to megascale factories.
Fabs differ greatly according to size, intended function, and level of technology. A typical fab is a self-contained appliance internally divided into a hierarchy of cellular compartments that range from nano- to macroscale dimensions. Each cell contains a specialised manufacturing system within an appropriate environment (liquid, gas, vacuum etc). At the smallest level this may consist of molecular tool-tips designed to make or break specific chemical bonds. At the macroscale, omnitools can affix, weld, forge, or otherwise assemble the final product. Vascular networks and smart matter membranes transport power, coolant, feedstock, and partially constructed components from cell to cell. In operation smaller cells synthesise parts (through chemical/mechanochemical means) that are transported to larger cells to be modified or combined with other parts. This process repeats until the final product is put together in the largest chamber and extruded from the machine.
Some fab designs are capable of operating in reverse-mode. Objects placed in these fabs for disassembly are analysed by the unit to determine the safest protocol; the material is then ground down by larger cells before being passed to smaller cells for digestion.
The product range of a fab depends on its intended purpose; the more specialised a unit is, the more efficient it will be at creating specific products (though non-fab specialised machines will almost always be faster/more efficient). For example; mealfabs are a feature of many biont's kitchens and many vecs keep a unit that can produce spare parts or power units. Industrial fabs are typically specialised too, since versatility brings a cost in efficiency. Factory complexes satisfying megascale demand are often organised as a three dimensional sprawl of specialised fabs in all shapes and sizes. Dense networks of flostone conveyors, utility lines and gelbots are used for component transport and assembly.
In other cases specialised fabs are used to produce product in situ. This is particularly common on infrastructure projects for bridges, buildings and other fixed constructs. In these cases mobile fabs arrive on site, spread over the assembly area and grow the product directly. Specialised fabs are still regarded as a class of fabricator if they retain the ability to return to a generalist form. This despecialisation usually requires a significant amount of time, energy and material.
Autofab production efficiency greatly depends on the toposophic level of its designer. Modosophont created units have long since plateaued at an average construction rate of 10kg/m3/hour, though this is a wide average. The more complex an item is (i.e. the more smaller, specialised cells involved in its manufacture) the slower it will be produced and vise versa. This average rate scales up-and-down to a point; generalist fabs cannot be built smaller than one litre in volume as they lack sufficient space for the range of constructor cells necessary to be universal assemblers. However, with cleverly designed libraries they may be able to construct and install within themselves the tools necessary to build a desired product (or a further set of tools). Larger fabs or multiple fabs working in tandem can significantly speed up product construction time, albeit with diminishing returns due to the limits of final product assembly and maximum possible task parallelisation. Industrial fabs often have transport systems large enough for many sophonts to walk through abreast.
Transapient designs have been observed to produce orders of magnitude more product per hour by utilising superior quantum levitation, laser cooling, and plasma quench technologies. In addition, ultratech fabs can operate in configurations beyond a self-contained appliance. Transapient bushbot swarms can be characterised as a collection of "inside-out" fabs, capable of performing all manner of chemical alterations and manufacturing using their external limbs. Managing this feat whilst maintaining a high degree of production and a low error/failure rate is beyond modosophont science or understanding (though some argue this is an example of low-ground ultratech and it will only be a matter of time before modosophont technology catches up).