Every modern device is characterized by the presence of various types of electronic components that are critical to effective operation of the equipment. However, these components are susceptible to electromagnetic (EM) interferences, which can cause severe damages and even total failure of the device, if left uncontrolled. To prevent such damages, electronic enclosures are used in every circuit.
These enclosures can be made of various materials. However, the recent years witnessed a surge in the popularity of composite materials. Here are the top reasons behind increasing importance of these elements for enclosure designing.
Offers Better Shielding
The metal enclosures block EMI through reflection, and so, they are effective when the EM source is located outside the enclosure. However, when the enclosure contains the EM source, metal shields can reflect back the energy rather than eliminating it.
The composite enclosures, on the other hand, suppress the EM waves using both the reflection and absorption and so, is the perfect solution for internal EM sources. When coated with copper, gold or nickel, these enclosures offer better shielding without increasing the weight significantly.
Different composite materials come with unique advantages. The Polymer-matrix composites with their higher moldability reduce the need for seams in the housing which is essential for metal enclosures due to the leakage risks. The electrically conductive polymers, along with protecting components from EMI, enhance the connectivity too.
Thermoplastics, one common category of composite materials, are much lighter than the metal. The weight of a composite enclosure can be 40 percent less than the aluminum enclosures and 80 percent less than their steel counterparts. The weight reduces further with the hollow microspheres, making the composite enclosures perfect for unmanned aircraft-vehicles (UAV) and other military applications. For instance, the density of aluminum is 2.71 g /cm3 whereas the engineered polymers such as Polyphenylene sulfide (PPS) or Polyether ether ketone (PEEK) have a density of 1.3 to 1.35 g/cm3. Carbon microspheres have the density of only 0.17g/ cm3. Typically, the composite enclosures consist of PEEK with carbon fibers and microspheres that have a density of 1.4g/cm3. They weigh nearly 50 percent lesser than the same-sized other enclosures.
Offers Greater Resistance to Impact
The biggest advantage of the non-metallic enclosure is, they do not block the electronic signals. Along with it, the composite materials have excellent tensile strength, impact and bending resistance, a physical attribute which makes them preferred choice for the enclosures. They do not get deformed easily and can be sturdier than the aluminum, a highly used metal for enclosures. For instance, the fiberglass enclosures are excessively tough which let them withstand sudden impacts.
Corrosion is one of the major concerns for the metal enclosures. Aluminum is highly corrosion-resistant, although it has many limitations. Firstly, aluminum enclosures create a galvanic cell with the metals such as copper and steel which leads to huge metal loss. The protective coatings of cadmium can prevent such losses, but they are not much preferable because of the toxicity. The composite materials, on the other hand, neither corrode nor deteriorate. They can be exposed to extreme temperature, solvents, and chemicals. The galvanic compatibility of composite materials with the modern aircraft structures also made them a highly preferred choice.
Suitable For Unique Shapes
Metal enclosures have to be stamped, which apart from being a time-consuming and expensive procedure, often affects adaptability of the enclosures to complicated shapes. The composite enclosures are created using the advanced molding technology which facilitates designing of complex shapes including different three-dimensional features, integrated connector shells, and partitions. Even, the 3-D printing technology can also be used for low volume or prototype enclosures making the process faster and more economical.
Composite materials have become the first choice for electronics enclosures as they meet the requirements of most modern devices with their strength and tolerance to the harsh environment. Further, the compatibility of these materials with different manufacturing technologies also makes them suitable for those cases, where time or cost is a concern.