3D printing, more properly called additive manufacturing, has captured the interest and imagination of many observers who have been regaled with predictions that this emerging technology is the future of manufacturing. Well, not quite. Or should I say not quite yet? 3D printing does offer some unique and interesting possibilities, but the technology as it exists today is no threat to large-scale manufacturing. We will continue to make most products using traditional machinery and techniques, but there are a few notable exceptions where 3D printing is already changing the way things are done and proving to be a truly disruptive technology.
The form of 3D printing that is making most of the headlines, and driving the “maker movement” with home printers and public 3D printing services, is truly printing, in the sense that the printing devices look and work very much like an ink jet printer. In this approach, officially called “material Jetting” or “material extrusion”, material is deposited through a nozzle, layer-by-layer to a build up the 3 dimensional object. Generally speaking, this is a rather slow process (it can take 6 or 8 hours to print an object just a few inches across) and is limited to materials that are liquid (that can be hardened in a post-printing process) or materials that can be melted and passed through the nozzle, primarily plastics. Material jetting and extrusion do not scale – objects are printed one-at-a-time – and the only way to mass produce is to have masses of printers working simultaneously. Note that this may change over time but this is the state of the art as it is today.
According to 3dprinting.com, there are five other approaches to 3D printing recognized by the American Society for Testing and Materials (ASTM) committee F42 on additive manufacturing technologies including vat photopolymerization, powder bed fusion, directed energy deposition and others. In each of these other techniques, the material exists in the space where the object is being created and the material is hardened or changed through application of an energy beam (usually a laser) or other physical force. It is these other methods that open 3D printing up to more durable industrial materials like metals and ceramics.
GE’s recent purchase of two European 3D printing companies—Arcam AB of Sweden and SLM Solutions Group of Germany – reflects a growing recognition of 3D printing as a game-changing development in the manufacturing world. But GE is not going to be creating mass-market consumer products with its newly acquired technologies. The acquired companies will be brought into the GE Aviation division where Division CEO David Joyce said that they plan to use 3D printing more frequently in the power turbine and medical equipment businesses. GE’s press release notes that Arcam “invented the electron beam melting machine for metal-based additive manufacturing and also produces advanced metal powders.” SLM Solutions “produces laser machines for metal-based additive manufacturing.”
There are two major advantages of 3D printing compared to traditional material removal processes (machining): you can 3D print complex, intricate designs and produce parts that would be impossible to make (in one piece) with traditional methods, and 3D printing produces a lot less wasted material. In machining complex geometries from exotic (expensive) alloys, it is not uncommon to cut away considerably more than half of the raw material. 3D printing, by layering the material only where it is needed, produces no such waste.
Yet, none of these 3D printing techniques can scale and they are all relatively slow, albeit GE has said it hopes to make 3D printing faster by at least two to three times over the next few years, according to the Wall Street Journal. That limits 3D printing to low-volume, specialized part production, given today’s technology. 3D printing has revolutionized product design engineering (prototyping) and production of complex geometry parts in low volume. But it is not the future of high volume consumer product manufacturing, at least not with today’s technology.