Spotlight – Additive Manufacturing

Materials World magazine
,
1 Jan 2018

Gary Taylor, Regional Manager at additive manufacturing service provider EOS UK and Ireland, explains the transformative nature of additive manufacturing.

The production line, developed by Henry Ford in 1913, has not merely dominated but defined the industrialised society. The process was broken down into small, easily repeatable steps. Manufacturers took advantage of this to mass-produce items, often in low-cost jurisdictions rather than close to their intended market. Wholesalers and retailers would then buy these items in quantity, taking on the risk of finding a market for them.

Additive manufacturing (AM) will change all this. Using this technology, manufacturers can make even single parts profitably to order. They can produce new designs without expensive retooling, and because the process is increasingly automated and highly labour efficient, plants can be built where the customer works, allowing for the kind of bespoke, fast-turnaround business model that the market increasingly demands. 

How additive manufacturing works

AM describes any process in which a single component is manufactured through the addition of layers, instead of removal, of the base material. 

For instance, rather than starting with a block of steel and milling away excess material to create a new component, you begin with a digital design of the finished component, designed in a computer-aided design (CAD) programme. You then print this design by melting layers of steel powder. 

The industrial 3D-printing system deposits a uniform layer of the metal powder on the build platform. It then applies a high-powered laser, rated at anything from 100W to 1KW, fusing the powder into a shape that corresponds to a cross-section from the CAD design. 

Once the first cross-section has been created, the 3D printer lowers the build platform, deposits more powder on top of the completed pattern and repeats the process, creating the next cross-section of the design. This continues until the system has printed the whole component, layer-by-layer. The process is known as direct metal laser sintering (DMLS).

Materials that can be used in DMLS include aluminium, cobalt chrome, nickel alloy, titanium, polyamide plastic, high-impact polystyrene and glass-bead filled polyamide.

The method used varies depending on the material. DMLS is used for metals, whereas laser sintering is used with polymers. The latter works in much the same way as DMLS, but instead of a high-powered laser and powdered metal, a UV laser is focused on photopolymer resin. As before, the laser traces the outline of a cross section of the design, this time on the photopolymer, which hardens on contact with the laser beam. When one layer is completed, the baseplate is lowered, more photopolymer laid down on top of the completed layer and the process begins again. 

Components produced in this way have durability often comparable to that of parts created with traditional methods. A recent study published in the Journal of Orthopaedic Surgery and Research found that orthopaedic plates – used internally to treat bone fractures – created using DMLS are stronger than those milled with a computer numerical control lathe. In 2017, the European Space Agency replaced the conventionally manufactured injector heads of the Ariane rocket engine, a component with class one rating for its importance to the mission, with one created using additive manufacturing. The rocket engine was built as a single unit – it had previously required 248 separate elements when assembled with traditional manufacturing processes.

Business Insider defines this on-demand economy as ‘economic activity created by technology companies that fulfil consumer demand via the immediate provisioning of goods and services’. This is accurate as far as it goes, but also insufficient. The same model holds just as much appeal for a company wishing to minimise inventory, for instance of spare parts, as it does for a consumer.

Because of the limitations of traditional manufacturing technology, until now the on-demand economy has mostly been confined to digital goods. The adoption of AM removes these limitations. A manufacturer can download a CAD design for an entirely new component, start making it within minutes, and do so at a profit even if it only produces and sells a single unit. 

Businesses take advantage of the flexibility offered by AM to be more efficient. For instance, Mercedes Benz manufactures spare parts for its trucks on demand using AM, which allows it to cut costs and respond to customer needs quickly. 

AM can be used for incremental growth, developing an existing business model in new directions. Aerospace systems manufacturer Liebherr used AM to create a new line of hydraulic valve blocks for Airbus that was cost-effective and greener than their predecessors.

Redefine manufacturing success

Because it liberates manufacturers from the limitations of traditional machine tooling, AM allows for the development of new applications. Low incremental costs incentivise innovation, and fast turn-around times mean new business models, built minimal inventory and just-in-time supply of even the most mission-critical components.

For those companies able to innovate, AM promises a manufacturing revival and the prospect of new subscription-based business models, similar to those we’ve already seen in markets such as software, digital media and fast-moving consumer goods – but this time, in the industrial supply chain. AM will be the driving force behind the next industrial revolution – a revolution that is already underway.