Mechanical Design

Designing for space is a delicate balancing act, as every gram counts. The antenna for a client’s space debris radar had extremely intricate geometry, as the many waveguide channels were tightly interwoven around each other.

The only way to manufacture it was investment casting (with some post-machining). And the master for the mould had to be 3D printed. Every twist and turn of the internal channels had to maintain a constant cross-sectional width. This strict requirement was combined with a manufacturing constraint that precluded any undercuts – so the antenna very challenging to design.

After weeks of experimenting using CAD, the Plextek team finally arrived at a design that fit all the requirements. The manufacturing required multiple suppliers – each contributing to the process in turn – but each step had been carefully considered and it all went as expected.

The radar was assembled and tested, then launched into space – and eventually incinerated in orbit at the end of its planned life!

Protection of coastal borders is vital to help target smugglers and prevent illegal entry. The challenge from ATLAS Telecom was to design and manufacture 20,000 tracker units as part of its next-generation E-Passport programme aimed at improving border control.

As the units were to be fitted in boats to track their GPS co-ordinates, an IP68 rating was required – which meant they had to withstand submersion in 1.5 m of (sea) water for 30 minutes. The Plextek team built a custom test rig to ensure the prototype was waterproof – as finding a leak at a later stage could delay the project launch.

Selecting the plastic for the enclosure was an important decision – it needed to be strong enough to withstand engine vibrations and be chemically stable under the UV rays of the sun. Exposure to chemical agents used to clean the boats also had to be taken into account.

Sample chips of various plastics were tested against the relevant cleaning products to select one that was unaffected. Once the first batch of products was assembled, the next step was vibration testing, followed by ‘accelerated lifetime’ testing in an environmental chamber – cycling through dramatic temperature and humidity changes. The product passed all tests first time and is now successfully being deployed on ships.

Ensuring runways are kept clear of foreign object debris (FOD) is crucial in the aviation industry, as major damage can be caused if debris is sucked into an engine. But traditional visual inspections are time consuming and prone to human error.

When Plextek was asked to create a FOD detection radar for a South Korean airport, the radar needed to withstand the acceleration and braking of the vehicle it would be mounted on – and operate in all weather conditions year-round.

The radar itself would be mounted on a rotation stage, which would precisely control the radar’s scanning. This would be connected to many control units, which each needed their own enclosure with screening and heatsinking.

The entire product had to fit under a large radome – about the size of a domestic water butt – which was made by wrapping layers of woven film designed specifically for its radio frequency (RF) transparency.