Page 39 - Materials Australia - April 2019

The manufacturing sector has been central to the development of our nation and the economic prosperity we enjoy today. After World War II, tariffs and taxation laws were put in place to ensure we manufactured our own goods. By the 1960s, 26% of the workforce was employed in manufacturing, and it accounted for 25% of our GDP.
Unfortunately, it has been something of a crash-landing since those heady heights.
By the 2000s, the sector had significantly contracted. Manufacturing raised just 12.5% of the GDP, and the percentage of the workforce almost halved to only 11.5%. According to Parliamentary statistics, those numbers have dropped to 7.1%. Between November 2016 and November 2017, the number of Australians employed in manufacturing declined by 4.5%.
What is causing these alarming numbers? Economics is complex, but the simplest explanation is that our wages are too high, we don’t produce enough to warrant those wages and Government and industry leaders have failed to invest in the technology we need to keep up with our global competitors.
So, Where Does Additive
Manufacturing Come In?
Additive manufacturing is by no means a new technology. In fact, it has been in development since at least the 1970s and 1980s when new techniques for solid modelling were created. These developments meant that 3D geometries could be translated into mathematical terms. These equations could then be fed to equipment control systems.
The technology for additive manufacturing as we know it was developed at the Massachusetts Institute of Technology (MIT). In the beginning, it was used for rapid prototyping, which meant it manufactured by removing metal. The big breakthrough came about in the 90s, when the technology was used to create metal, instead of just removing it.
An MIT research team, led by Emanuel Sachs, invented 3D printing in 1993. The MIT research team developed a process known as binder jetting. This process can solidify certain areas of a part by squirting a layer of powder through a liquid binder. As layers are added, the process can create three-dimensional objects.
Other forms of 3D printing then came into fruition:
• Directed Energy Disposition: Used for repairs to add material to finished components, this process uses a multi-axis arm to deposit melted material onto selected areas.
• Material Jetting: This process works in the same way as a 2D inkjet printer. The required material is jetted onto a base, either selectively (Drop on Demand) or via a continuous jetting system.
The process of all 3D printing begins with a virtual CAD (Computer Aided Design). When recreating an object, a 3D scanner can be used to make a copy and then transfer the details of the copy into the 3D modelling program.
The software used in the process works by slicing the final model into many different horizontal layers. So, when the prepared file has been sent to the 3D printer, it can move layer by layer. It reads every 2D image and creates each layer with no visible signs of layering, meaning the final product is a singular three-dimensional object.
This process gives manufacturers incredible freedom. Without the need for programming or machining, parts can be created in a production unit that is both singular and flexible. That’s not all this technology offers.
Meeting Modern Demands
Traditional manufacturing methods imposed restrictions on part optimisation. Additive manufacturing and 3D printing remove these restrictions, particularly around concerns like undercuts, draft angles and machining capability.
This flexibility means that part geometries can be optimised in service, instead of performance being forever locked to the initial manufacturing process. Unitisation makes for significant savings, especially compared to the process of making joined parts as single units.
This has had implications for areas such as chemical reactions, heat exchangers and electrochemical reactions which have been made more efficient thanks to the higher surface area to volume.
The technology has also been incredibly beneficial for the biomedical and aerospace industries. It has allowed for the creation of biocompatible materials, as well as materials with incredible strength to weight ratios. Decreased costs and increased production also make the products associated with these industries more accessible.
APRIL 2019 | 39
FEATURE – Additive Manufacturing
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