Undoubtedly, higher requirement has always been laid to electronics products that’ll be used in extreme environment compared with those in ordinary environment. The manufacturing of electronics products that’ll be used in hostile environment mainly ranges from PCB design, PCB fabrication to PCB assembly all of which determine the performance and reliability of PCBs and terminal electronic products in the environment of extreme temperature or humidity. As a core in electronic products, PCBs play a significant role in controlling their performance.
Therefore, this article will discuss the leading concerns of electronics products manufacturing for extreme environment based on details during PCB design, PCB fabrication and PCB assembly procedures.
PCB Design
When the working current of a board is designed to be 5 ampere, it’s best prior to layout and simulation to add a buffer that plays a role of alert once the working current reaches the warning level. As a result, even if the final product is exposed to extreme heat during its application and the working current goes up, it won’t be damaged.
When a 6-layer PCB is ready to be used in extreme environment, it’s optimal to add two layers to it to reduce the possibility of crosstalk since the adding of two layers is capable of providing more ground. The more solid ground is, the better signals become separated. In addition, adding two layers is also beneficial for circuit board to be free from mixed signal interference and to keep SNR (Signal Noise Ratio) at an acceptable domain. As a result, the reliability of PCB can be increased by 15% to 20%.
Shielding should be added to key circuits, especially clock circuits, through which the reliability of PCB can be also increased by 15% to 20%. When it comes to RF circuits, aluminum shielding is suggested to be added so that sensitive signals can be departed from each other and become clear and neat.
PCB design optimization measures can be also made from the following aspects: adding redundancy modes, component pickup, feedback circuit, monitoring circuit and extra protection and warning on analog/digital signals.
PCB Fabrication
PCB material has to be totally considered in PCB fabrication and layout. As far as extreme environment is mentioned, material should be picked up to resist extremely high temperature, such as FR4-008 or polyimide substrate material which cannot only resist extremely high temperature, but fails to be delaminated in extreme heat and fails to cause solder mask film to fall as well.
Since PCBs that’ll be used in extreme environment usually have to be confronted with extreme heat and temperature fluctuation, circuit board should be stopped from warping because warping will possibly cut down circuits, damage solder joints, leading to issue occurrence during its application.
PCB Assembly
Compared with ordinary PCBs, the circuit boards that have to be used in hostile environment call for particularly high reliability. During PCB assembly procedure, inspections have to be made to guarantee the quality of finished products. For example, AOI (Automated Optical Inspection) instrument should be used to inspect the performance of solder joints; solder paste thickness measurer is used to judge whether solder paste features optimal thickness that’ll contribute smooth reflow soldering in later steps of SMT (Surface Mount Technology) assembly.
Apart from professional inspections, first article inspection and approval are also of great significance for electronic products used in extreme environment. First article inspection ranges from temperature cycling test, drop and swing test, mechanical intensity test etc. All the inspections and tests allow all the issues to be solved at the first beginning of product engineering to stop them from bringing forward catastrophic results in real applications.
Well, it’s hardly possible to list all concerns for the manufacturing of electronic products used in extreme environment. Although this article can tell you all the possible concerns and solutions for electronic products used in extreme environment, high quality still tops the list. The optimal solution lies in your cooperation with a reliable PCB solution provider that can assist you in quite a lot of important aspects including co-designing based on cost reduction and performance optimization, experienced one-stop PCB solutions etc.
Plus, OEMs (Original Equipment Manufacturers) should keep in mind that the cost has to go up of electronic products used in extreme environment. Thus, a reliable EMS (Electronics Manufacturing Service) provider should be relied on since they are experienced enough in electronics industry to make the best of what’s been supplied by their consumers. Additionally, the situation will be much better when EMS providers are certified by IPC, ROHS, ISO9001 etc. since the performance of products can be totally guaranteed.
