^ Robust screws fix the titanium plate to the clamping mechanism before it rotates through 180° for the sawing operation.

Text & images by KASTO Maschinenbau GmbH & Co. KG, Germany

No sector takes the issue of lightweight construction as seriously as
the aviation industry, and with good reason: every gram that can be
trimmed off an aircraft’s weight helps achieve considerable long-term
fuel savings. This benefits both airlines and the manufacturers, who are
able to compete for orders by offering ever more lightweight
constructions. However, aircraft components not only have to be light;
they also have to be stable and absolutely reliable. That is why special
high-tech materials and innovative manufacturing methods are becoming
increasingly widespread in the production field.

Airbus Helicopters is consistently searching for innovative lightweight
construction solutions. The company is part of the Airbus Group,
Europe’s largest aviation and aerospace company. The site in Bavaria,
which has a workforce of approximately 7,000 employees, not only
develops and produces a range of helicopter models such as the H135 and
H145, but also specialises in the manufacture of aircraft doors. In
Donauwörth, Airbus Helicopters manufactures more than 4,000 passenger
and cargo doors every year.

Layer upon layer

Airbus has been using an additive manufacturing process to produce
shafts for locking these doors. The titanium component is created in a
3D printer, which applies layer after layer of the powdery input
material to a baseplate measuring 400 x 400 millimetres.

The fact that walls of the shaft are thin and that it has a complex
geometry makes this manufacturing method particularly suitable. It cuts
production costs as well as work and effort – and most importantly:
sixteen of these components are installed in every A350. That adds up to
a saving of slightly more than four kilograms per plane.

When the printing of the components is finished, they must be separated
from the baseplate, which is also made of titanium. To perform this
process, Airbus has invested in the KASTOwin amc fully automatic
bandsaw. The machine has been in operation in Donauwörth since October
2018. The saw is specifically designed for the machining of additively
manufactured parts.

Turning device prevents damage to the workpiece

An employee uses an electric lift truck to remove the baseplate and shafts, which can weigh up to 40 kilograms, from the 3D printer, transports it to the saw and places it on the clamping mechanism. Here, the plate is securely fastened in place with robust screws and the machine is locked so that no fine dust can escape. What happens next is rather unusual: The entire mechanism rotates through 180 degrees for the sawing operation so the components are sawn upside down. This concept is unique and offers considerable advantages for additive manufacturing. After being cut, the parts cannot topple over or buckle – this prevents damage that could lead to time-intensive reworking or even expensive scrap levels.

Before the sawing operation begins, the employee measures the thickness of the clamped baseplate and enters this using the job wizard of the Advanced Control machine control system. The top part of the saw, which is equipped with a high-precision ball screw spindle drive, then moves to the exact height required. Because the plates can be reused many times and are ground flat again after each operation, they become thinner the more they are used. The intelligent control system makes it possible to saw the parts precisely to the corresponding dimensions on each individual operation. This also reduces the reworking effort and saves material – a cost factor that should not be underestimated when working with a material such as titanium.

Fully enclosed design

When cutting is complete, the shafts fall into a container specially provided for this purpose. This is padded to prevent any damage to the parts. The operator removes them through a flap so that they can pass on to the next machining step. The KASTOwin amc is fully enclosed to prevent the ambient air from becoming contaminated with tiny particles, which are detrimental to health and may arise during the machining of additively manufactured components. The machine is also prepared for the connection of an extraction system, making it compliant with the most exacting requirements regarding occupational safety and operator protection.

Before choosing the machine, Airbus’s decision-makers conducted a number of trial cuts at the saw technology specialist’s premises at Achern in Baden-Wuerttemberg. Sawing the titanium plates proved to be significantly more cost-efficient than alternative machining methods such as milling or electrical discharge cutting.

For Airbus, the changeover to the 3D printing process and the acquisition of the KASTOwin amc have already paid for themselves. The shafts, which will subsequently be used to lock aircraft doors, are 45 percent lighter and 25 percent more economical to manufacture than conventional components. Airbus Helicopters currently manufactures approximately 2,200 of these titanium components at its factory in Donauwörth. The additive manufacturing of other components is also planned for the future.

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