Materials Processing Extra Credit
Why do additive manufacturing technologies have high applications in aerospace industries? To
start aerospace makes up about 18.2% of the total revenue in AM field. It also saw a 1.6% annual increase
in 2016 (Joel C et al. 7). In an ever-growing field, it is easy to see why companies are so eager to further
develop and implement these technologies. AM was first used by Boeing and Bell helicopters back in the
mid-1990s when polymer parts were used for nonstructural components. Fast forward to 2015 when
Boeing developed and fabricated over 200 purpose-built parts using AM for use in 10 different aircraft.
This figure has since increased to tens of thousands of parts made with AM on 16 different aircraft
(Joel C et al. 7). The reason for this ever-growing figure comes from the demand of the aerospace
industry. Using AM lightweight components can be made with complex geometry offering very high
strength-to-weight ratios. The complex geometry regularly used and developed using AM would be
difficult and expensive to manufacture using other traditional means.
As mentioned earlier AM has had a massive effect on the economics of the aerospace industry. A
prime example of this is the buy to fly ratios previously seen when CNC tooling was one of the only
options. Ratios of 20-40:1 are common. Meaning above 95% of the material could be wasted when
traditional CNC tooling is used (Joel C et al. 11). This further highlights an advantage of AM especially
when the material being wasted is considered. High-value metals such as titanium are often used in the
aerospace industry meaning this 95% waste costs companies a fortune. PBF AM cuts the percentage of
waste down to about 5% as hybrid milling is often used after the fact to achieve a nice surface finish on
parts (Joel C et al. 11).
AM is not as cost-effective for large production runs of single parts. However, with little to no
tooling costs or initial investments needed to equip the facility smaller production runs of customized
parts make AM much more cost-effective than traditional means of manufacturing (Joel C et al. 12).
These smaller production runs are prevalent in the aerospace industry where rapid production, testing, and
shipment of new parts is common practice for repair or updates of units (Joel C et al. 12).
Direct metal part fabrication is maturing in this industry as well. Most notably by companies such
as TWI (the welding institute) where helicopter combustion chambers are being manufactured on 5-axis
metal printers. These 5-axis printers allow TWI to print complex overhanging geometries by changing the
orientation of the piece. This allows them to print without the need for supporting material
(Joel C et al. 12). A company out of Switzerland was able to use direct metal part fabrication to reduce the
weight of a part by 40% and reduce production costs by 3 million. All were achieved with direct metal
fabrication AM (Joel C et al. 12).
Multilateral AM has also been taken advantage of. The use of multiple materials allows designers
to accurately predict and model how parts and components will behave under multiple loading cycles or
under thermal stresses. This increases part-life and efficiency (Joel C et al. 12).
AM manufacturing has allowed designers to assign parts multiple functions. Much like
how the engine in some motorcycles is an integral part of the overall structure of the frame a similar thing
is being done with aerospace. This has been achieved by part consolidation Part consolidation allows
parts to be more reliable and have greater performance. It also requires less tooling and equipment to
manufacture, reducing inspection times, reducing assembly line footprint, and shrinking overall
manufacturing costs. GE Aviation has reported consolidating 855 parts into a dozen parts by using AM
practices. This simplification of design not only helped to manufacture but also increased performance
with an increased fuel efficiency of 20% and an increased net power output of 10% (Joel C et al. 10-11).
Airbus was also able to take advantage of AM by consolidating 126 different parts that made up a
hydraulic housing tank into a single part.
Another example of this is structural parts that act as conduits for electrical wires or even cooling
channels (Joel C et al. 9). These cooling channels are especially important because it allows the aircraft to
pull heat out of important components which allow for better performance.
Examples of future applications of multi-functional parts are embedded electronics within
structures or surfaces, structures with rigid and soft material compositions, integrated sound and thermal
insulation, and 4D printing (Joel C et al. 12). 4D printing refers to parts that change with time. Meaning if
exterior weather conditions change the geometry of the wing could be designed to match these conditions
to provide greater fuel efficiency.