Unmanned aerial vehicle (UAV) is a kind of unmanned aircraft operated by radio remote control equipment and self-contained program control device, or operated by on-board computer completely or intermittently.
Composite materials used in small UAV, such as fuselage, wing and other structural components, are mostly carbon fiber prepreg with higher specific strength and modulus. In recent years, the quality control of small UAV is more and more strict, the proportion of carbon fiber in composite UAV is gradually increasing, and even the small UAV made of all carbon fiber composite material appears. In addition, the low resistance of carbon fiber also makes it used in stealth design of aircraft.
Concept of waterproof unidirectional permeable membrane: Waterproof permeable membrane is a new type of polymer waterproof material. From the production process, the technical requirements of waterproof and breathable membrane are much higher than the general waterproof materials; at the same time, from the quality point of view, waterproof and breathable membrane also has the functional characteristics that other waterproof materials do not have. Waterproof and breathable membrane not only enhances the air tightness and water tightness of buildings, but also has its unique vapor permeability, which can quickly discharge the water vapor inside the structure, avoid the growth of mold in the structure, protect the property value, and perfectly solve the problems of moisture-proof and human health. It is a new energy-saving material of health and environmental protection. Development history of waterproof unidirectional breathable membrane: the 20th century
PCB multilayer board is also called printed circuit board, also called printed circuit board, printed circuit board. Multilayer printed circuit board refers to more than two layers of printed circuit board. It is composed of connecting wires on several layers of insulating substrate and pads for assembling and welding electronic components. It not only has the function of conducting each layer of circuit, but also has the function of mutual insulation. In the manufacturing process of PCB multi-layer board, the riveting method between layers is a very important link. Its main purpose is to first fix multiple inner core boards together by riveting or fusion, and then combine multiple inner core boards into a whole ipnl board through PP through high temperature and high pressure. By riveting