3 Electronic Enclosures for the Aerospace
As the 21st century progresses towards a faster world, managing a massive volume of data has become a necessity for every single industry. And to stay at par with this advanced data management needs, innovation is taking place at a rapid pace. The aerospace industry is not an exception.
Some of the initiatives in this field involve using sophisticated and customized off-the-shelf enclosures for protecting all sensitive equipment from electromagnetic interference (EMI). While focusing on the space applications and the innovation related to it, the last three decades witnessed a steady and significant advancement.
If you go deep into the space studies and satellite designing, you will understand that their coverage range is vast and widespread. Be it the imaging of planet Earth or telecommunication services that are covered, the range has expanded over the past few decades, and the growth of satellite applications is likely to further increase consistently.
The development of electronic equipment has a history. In the early 1970s, NASA identified that most of the spacecraft damages were due to immense vibration during the launch. To address this problem and add life to the spacecraft, structures were made to undergo a series of evolutions. As part of this process, while designing space electronics, engineers started to focus on the performance improvement with an assembly of designs.
Primarily the entire equipment unit was made up of aluminum alloy. For example, NASA has already put in a lot of efforts to encourage the designing of lightweight electronic enclosures which enhance the flight safety. All these initiatives resulted in the development of three different types of boxes which are developed independently – the light-weight Aluminum box, the cast Aluminum box, and a composite box.
The Necessary Design Requirement in Manufacturing Electronic Enclosures
There are three functional elements which have to be incorporated while designing the housings. They are:
- During every launch, there’s a sufficient amount of load that falls on the aircraft units. The individual housing must provide an adequate structure to assemble and mount cards.
- Each of the housings must have sufficient thermal path to dissipate the heat. During every single launch, a substantial amount of heat is generated. It is essential to do away with the heat and maintain the composure within the unit.
- Both the output and input cables should establish a systematic connection with the motherboard.
In the initial stage of design, all these requirements are drawn out mentioning electrical, mechanical and also the thermal details. This detailed plan helps manufacture the boxes according to the requirements.
Of all the boxes manufactured for an electronics enclosure, the most traditional is the lightweight machined Aluminum box. When the Aluminum box was designed, it was made with the notion of replacing an outdated box that hardly served the purpose. The new generation of Aluminum boxes replicates the fabrication and constructional features of the older boxes. The design includes a six-sided enclosure, and each of the sides was machined and assembled individually with the help of assemblers.
Each of these aluminum boxes can hold maximum fourteen cards, and if extra cards are to be accommodated, an additional box has to be set up. These boxes meet most of the pre-requisites by default, and hence these Aluminum boxes are preferred over the rest. These units come complete with small overhangs to provide necessary EMI shielding. These Aluminum boxes offer an ideal example of how weight can be removed from a conventional structure.
Cast Aluminum Enclosure
This is the second category enclosure box which is popularly used in the aerospace industry. Even though the basic element doesn’t change, it goes under specialized casting before the manufacturing process begins. Instead of six sides present in the earlier variety, the cast aluminum enclosure consists of four sides, along with separate front and back covers.
However, the design of the box went under multiple testing with wax molds being created before letting the cast Aluminum go through it. Once the wax mold was carved out, the next step involved the preparation of a ceramic mold. Not only the finesse was put in, but the mold also went through multiple heat treatments as well.
There are multiple features which help the box attain a high level of EMI shielding efficiently. Each of the sides has been grooved so that the heat transfer from the sinks can take place to the core structure. However, the entire essence of success lies in manufacturing an enclosure that had thinner walls reducing the weight, but maintaining the same level of tolerance. Also, the techniques applied to the EMI Shielding were similar to the machined aluminum enclosure.
This is one specific arena of which has consumed a substantial amount of time in the research process, but with limited progress. The reason why composite materials have been preferred over the rest electronics enclosures is the material stiffness and better thermal conductive nature.
Even when it is required to carry a high thermal load, these composite materials can be a good choice in manufacturing light chassis. When the composite enclosures are manufactured, flat laminates of separate configurations are being assembled in the form of a box that can hold up to six to fourteen cards. As the cheaper structural materials are utilized for manufacturing the chassis, expensive and highly conductive materials are used in the interior portions.
With a stiff structure, the primary infrastructural requirements are easily met, and the judicious placement of highly conductive elements gives a stable thermal system to the entire enclosure.
‘Save weight’ is the go-to mantra of all three types of enclosures described above. Apart from that, you should focus on data handling systems if you want to design electronic enclosure for the aerospace industry, as the sector has to deal with a lot of them. Also, before procuring EMI shielding casings for aerospace electronics, make sure that the design of the products meets all compliance and thermal testing requirements. The three enclosures of our article, are designed to meet the compliance guidelines without adding to the cost or weight.