The global take-off of additive manufacturing (AM, popularly called 3D printing), it is now apparent, took place some six years ago. "2012 was a turning point in AM, globally," consultancy Wohlers Associates president Terry Wohlers tells Engineering News Online. "The technology really gained attention, investment and traction, in comparison to what had been the case previously."
The global AM sector grew at an annual average rate of 24.9% over the four years from 2013 to 2017, he notes. The total publicly available value of the sector was $7.34-billion last year. ("Publicly available" because this total excludes the value of parts made, using AM, by many manufacturers, because such data is difficult to obtain; the true total value is thus much higher.)
In addition, many major manufacturers now make use of AM to rapidly produce prototypes of new products. The simple cash value of such work might be low, but its importance for the companies concerned is huge.
Moreover, there is now a much wider range of materials that can be used as feedstocks for AM. This has been the result of the development of AM machines and techniques which are more "open", or agnostic, in terms of the materials they can handle.
Whereas once AM machines could only be used with certain plastics (polymers) and titanium and certain titanium alloy powders, today a much wider range of both plastics and metals can be employed. Regarding plastics, some photopolymers are now being used, as well as a wider range of thermoplastics. Carbon composites are also being used, but nylon is especially popular.
The range of metals employed in AM, usually in powder form (but some in wire form) is now quite extensive. In addition to titanium and titanium alloys, these include stainless steel and tool steel, cobalt-chrome alloy, and nickel-based alloys (especially Inconel). And now precious metals are also being subject to AM -- gold, silver and platinum. There is a platinum AM project currently being developed in South Africa.
"The range of applications for AM is getting ever wider," highlights Wohlers. "This is because the costs of AM are being driven relentlessly downward. The costs of both machines and materials are much lower than they used to be. However, industrial-scale machinery and materials are still expensive. Some materials for industrial-scale AM can be fifty times more expensive than the equivalent materials for conventional manufacturing. Costs are coming down, but not as fast as many would like."
Currently, the commercial low-hanging fruit for AM includes medical devices, aerospace parts and some power and energy applications. "Medical devices and aerospace parts are both low volume, high value and often very complex items," he notes.
Other low-hanging fruit is provided by consumer products, like jewellery. A recent development, with much promise, is using AM to produce customised footwear for individuals. And a consumer product AM is now being used to mass produce is, oddly enough, mascara application sticks. "AM also allows the personalisation of products for individual customers."
Although the automotive industry has used AM for years, it has done so in only niche applications, such as prototyping and the production of some small parts. The sector has not, as yet, made any substantial use of the technology. "But once they do adopt AM, it will drive down the costs considerably," he points out. "And Daimler is now starting to use AM to manufacture parts for their trucks, to avoid having to maintain spares stockpiles in warehouses -- the 'print on demand' concept. Once this moves to cars, it should have a big impact."
For the near future -- the next two to five years -- Wohlers expects the price of metal AM machines will decline significantly, due to greater competition in the AM machinery production sector. "With reduced cost, it will be possible to affordably 3D print light fittings, wall hangings, art works -- even guitars. This can already be done, but the products are very expensive. Another potentially big market will be low-volume special event corporate give-aways, where AM will enable a company to give each of its guests personalised gifts."
"It's very exciting to be part of this," he enthuses. "There is something new almost every day. AM is dominated by young researchers. Putting AM with computer design softwares allows us to learn from nature -- complex, lightweight, strong structures, such as found in the bone structures of birds. Bio-mimicry is a real opportunity and the next frontier!"
Wohlers gave a keynote address at the 2018 Rapid Product Development Association of South Africa (Rapdasa) conference on Wednesday. This was Rapdasa's 19th annual conference.