Additive manufacturing of metals, also known as 3D printing, is fast finding its way into the aerospace and defence sectors. The reasons for this fast uptake is the realisation of benefits derived from prototyping and optimising parameters, enabling the examination of weight properties and improvement in part design. Another dimension can be added to these opportunities: replication at third-party sites via integrated networks, making part production possible anywhere in the world.
To gain a better understanding and appreciation of the opportunities involved, each of these ideas is explored below.
- The value of weight properties
Today, the metal of choice in the 3D printing of parts is titanium. Its particular lightweight properties are important to the aviation and space industry. In a recent report by the US Department of Energy Advanced Manufacturing Office it was demonstrated that a 7% reduction could be achieved in overall aircraft weight simply by installing titanium parts produced using 3D processes. A 7% weight reduction is a highly significant figure; where most weight efficiencies only achieve one or two percentage points, a 7% saving will have a substantial impact on fuel costs, thereby reducing overall operational costs.
The ability to prototype critical parts provides insights into not just what is possible but into the best practices for additive manufacturing. By way of example, SLM Solutions, headquartered in Lübeck, Germany, recently produced a single titanium aerospace component measuring 221mm x 310mm x 219mm. Using the SLM280HL laser system, with a standard build plate of 280mm x 280mm x 365mm, it became possible for the production of this large-sized valve body. The SLM280HL is equipped with multi-beam technology utilising dual 400W lasers, making it possible to build a part this size in a relatively short time-frame when compared to conventional manufacturing such as machining it out of a billet, which would have taken several weeks. Casting a part would have taken even longer as the tooling would have to be built first.
With the 3D-printing process only one initial ‘set-up’ was required, a significant reduction to the four or five set-ups the same part would have required using conventional processes. Additionally, no operational interruptions were experienced during the six-and-a-half days of the build reinforcing the reliability of the SLM280HL laser system.
- A designing revolution
CAD programs are noted for producing complex designs that can then be built with 3D-printing processes. The large spacecraft valve body printed on the SLM280HL laser system was not particularly complex, but the use of titanium, which is a very hard material, could subject a large part to cracking due to high residual stresses. The SLM280HL uses a pair of lasers working simultaneously, and while this increased the speed of production, questions were raised regarding the reliability of the sections of ‘overlap’.
These were subjected to testing, resulting in no differences in quality between of the area built by one laser and the overlap of the build from the other laser. This finding was important for 3D-printed components, as all parts are required to meet stringent testing in the highly regulated industry of aerospace. Metals parts may need to undergo computed tomography to check for porosity or internal voids, or they can even be subjected to destructive testing where the product is simply pulled apart, such are the standards of regulation.
Reliability of production was a key achievement, but upon realising the opportunities, the aerospace industry then sought to uncover further benefits beyond the weight of titanium. In 2016, GE Aviation was able to produce fuel nozzles for CFM International’s LEAP high-bypass turbofan engine, used in the Airbus A380 as a single part, reducing the normal complex production process of making and joining 18 different parts together that performed one operation. By exploring and testing part functionality, the company has reduced part count, a real cost efficiency gain and a significant step forward.
This single, lightweight, 3D-printed fuel nozzle has now been put into service, revealing a degree of durability five times that of the conventionally manufactured part, a further testament to the reliability of 3D part production. GE engineers have broken new ground by producing a part that could not have been made before, opening the way for the re-examination of part counts in all industries where mechanical properties are critical to functionality.
- Replication options – Local or distant
CAD programs are used for the initial product design. Once it is computerised, the computer that is controlling the 3D build process interprets the specifications of the design. This process can be described as an embedded system using intelligent controls.
Everyday examples of embedded systems are the ABS brakes in our cars or the smartphones we carry with us daily. Each operates as an information-processing system, embedded within an enclosed product, performing a set range of device-specific applications. This intelligent processing provides a further opportunity if we consider incorporating it into the global network, in other words uploading the CAD program to the internet for use in a distant location where 3D printing technology is available.
This procedure could overcome problems surrounding the time-critical supply of parts. For example, if a fuel nozzle from an Airbus A380 needs replacing when it lands in Australia, the design can be transferred to a local manufacturer. The turnaround would be reduced to hours, as opposed to days, providing a significant reduction in time and costs. This situation allows not only for a rethink regarding the location of part manufacturing; while it does raise issues of copyright and ownership, it also provides opportunities for the cost-effective entry into global markets. This consideration is important given the climate of change in Europe, and the German government’s push towards Industry 4.0.
- Industry 4.0 – The opportunities
The German government is very serious about Industry 4.0, providing billions of euros in funding as one of 10 future projects it has identified as opportunities for Germany to establish itself as an industry leader and provider of relevant products.
Building on embedded processes and incorporating global networks forms the base of Industry 4.0, or the technological evolution from embedded systems to cyber-physical systems. This paradigm shift is from centralised to decentralised production, as demonstrated in the example of supplying a part for the Airbus A380. It is simply building on what we already have – computerised design and the internet – which are enabling technologies that have the potential for building a global business in a whole new way.
How can 3D printing on an SLM Solutions laser meet the challenges of Industry 4.0? One solution lies in the already existing demand in the aerospace and defence sector that continues to lead the development and production in additive manufacturing worldwide.
Australian manufacturers should not feel they are in an exclusion zone – quite the contrary. Defence procurement focuses on highly specialised products, often constrained by quantities, like the two Canberra Class Amphibious Assault Ships (LHD) currently in service in the Royal Australian Navy, and the planned commission of the 12 Barracuda Shortfin submarines to be manufactured in South Australia. The initial build of these items requires a limited number of specialist parts that are often designed and constructed by third parties, but as products age, parts will need to be replaced and due to their specificity, issues can arise if the original supplier is unable to supply on time or cost. It opens the door for part manufacture in Australia.
Already SLM Solutions lasers systems are being used to prototype and test parts for the Australian defence sector, but the doors are not closed to third-party suppliers with in-house technological capability. The practice of Defence in strategic procurement will always result in this ‘limited’ supply line that can be penetrated by 3D-printed part production highly suited to unique designs and one-off or small-run solutions, easily undertaken by local manufacturers.
SLM Solutions is in a strong position to take advantage of Germany’s push to lead the market in the development from embedded systems to cyber-physical systems, providing an ideal solution for effective manufacture right here in Australia. Raymax Applications Pty Ltd is the Australian distributor for SLM Solutions.