Loosely defined, Digital Fabrication (DF) is the production of a physical object by a machine directed by a computer program.

What is DF really and was is the impact of DF on the construction world?

DF is closely related to “Computer Numerically Controlled” (CNC) machining. This technology was developed by big aerospace and automotive companies to control machines which cut (mostly) metals using (mostly) rotating cutters to produce complex components such as injection molds and aircraft parts. The production of these complex parts by hand required 1000s of hours of highly skilled labour, or complex jigs, or both. From the 60’s to the present day, the implementation of CNC machining progressively moved work to the office, where parts are designed efficiently on a computer, which then generates a program which in turn controls the machines which machines the parts. In fact CNC technology is so old that early programs were recorded on punched paper tapes.

The CNC process requires less total hours and less skilled human labour in the plant, which is the point. Additional benefits include greatly increased speed, as computers can direct machines must faster than a human operator can, while maintaining the required accuracy.

By the late 90’s the cost of machine control systems, raw computing power and the software to design parts had dropped to the point that the workshops of most metalworkers, signmakers, millworkers and machinists had a least one CNC router, LASER or waterjet. Because of the ubiquity of CNC machines and overcapacity in many North American clusters, there is no longer a significant competitive advantage to owning most CNC machines.

In other words, CNC machining has become commodified. Nowhere is this commodification more apparent than in the many Erwin Hauer imitators which have emerged. It seems that today, no lobby, condo kitchen or ad agency reception area is complete without an “Erwin Hauer” screen made from LASER-cut metal or machined and lacquered MDF.

Much of the current buzz surrounding DF is due to the fundamental difference between the old technologies, which are based on material removal, and the new technologies, which are based on building up materials. The later, collectively referred to as “Rapid Prototyping” (RP) processes, include “Stereolithography”, “Laminated Object Manufacturing”, Selective LASER Sintering”, etc. 20 years ago RP parts were not strong enough to actually use, but today many of the material / process combinations produce durable components. Gas turbine blades with complex forms are an outstanding example of a breakthrough application for 3D printing.

RP technologies are now approaching ubiquity in the field of industrial design, where they are used to produce one-off prototypes of things like dashboards, as well as short-run parts and patterns for molds to produce castings. One of our customers at FEFA incorporated sintered plastic shrouds in an electronic device we built housings for.

Proponents of DF in architecture claim that large-scale versions of RP technologies will revolutionize construction. Examples include concrete pumping machines which work like giant robotic “caulking guns” squeezing out concrete walls, alongside robotic crane manipulators assembling steel.

So how do these emerging technologies affect designers, architects and contractors?

The subtractive technologies such as CNC routing, waterjet and LASER cutting are used every day by sheet metal shops, millworkers, glazers, steel fabricators and stone setters because they are well adapted to the production of one-off or limited production components. This availability is attractive, but the pallet of options in solely CNC cut or routed parts has been widely explored and as a result, what I refer to as the “Dubai Look” (or the “topographic-map-look”) is already tiresome.

Unfortunately, the A&D world has to be careful when it comes to conceiving or designing objects for production by additive RP machines. It is very attractive to produce prototypes in minutes under one’s own control, but limitations on the size of parts and the extremely high cost of the additive technologies relative to alternatives limits practical applications for full size construction.

Recently, it has become fashionable for schools of architecture to install an RP machine of some kind. I have been invited to speak at or visit half a dozen and each time, students trot out miniature buildings fresh from a “3D printer”. My opinion is that this process should not be held up as “the future of building” just yet, since what the industry needs is designers who produce drawings which will successfully guide General Contractors and their subs, not just desktop printers.

In fact, exposing students to the instant but totally unrealistic gratification of the 3D printer may even have a negative effect, in that it further alienates the young architect from the nuts and bolts processes that will continue to underlie efficient construction for the foreseeable future.

My opinion is that students benefit more from the use of subtractive technologies, such as router tables and lasers, since these are in widespread use by industry, and will be for the foreseeable future.

Julian Bowron, June 2022