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Military PCB assembly is the process of making and putting together PCBs for military and defense equipment and devices. It is a critical process for military equipment companies and organizations. PCBAs connect circuits and perform the electrical functions of defense equipment. PCBA manufacturers must meet military-grade quality standards for certification because military PCB assembly requires high reliability and precision.To meet strict standards, military PCB assemblies should have the following characteristics: long MTBF (mean time between failures); long life; ruggedness; high performance. Also, to make the PCBA last longer and be stronger, a conformal coating can be added to military PCB assemblies after they are made.
military pcb assembly
Military PCB Assembly Standards
Every country has its own rules about what kind of military PCB assemblies are allowed. Military PCB assembly is usually required to comply with military standards (MIL-STD) or similar standards before a defense product project can begin. There are well-known international standards for military PCB assembly.
-MIL-STD-810G is the U.S. military standard for testing how well military equipment can withstand different environmental conditions.
-MIL-PRF-38535: This is a general specification for microcircuits used in military and aerospace applications.
-MIL-STD-454: This is a standard requirement for military electronic equipment.
Requirements for Military PCB Assembly
To achieve high performance, reliability, and durability, military PCB assembly has stringent requirements for PCB laminates/materials, components, and designs. Depending on the application, military PCBs include laminates made of Rogers, high Tg FR4, ceramics, copper, PI, and hybrid materials, such as Rogers/FR4/copper.
1.Military PCB laminates require:
- Low and consistent thermal expansion
Military PCBs operate in harsh environments (deserts, mountains) with severe temperature swings, demanding materials with low, stable CTE to prevent warping/buckling.
- Small and stable Dk and Df
Military high-frequency systems (e.g., radar) require laminates with stable, low Dk/Df to ensure signal integrity and minimize loss – driving the use of PTFE/Rogers and ceramic-based materials.
- Low moisture absorption
Laminates for military PCBs should have low moisture absorption to prevent corrosion and changes in dielectric properties in humid environments.
2.Military PCB components require:
- High reliability
Electronic components used in military must be highly reliable. Since military electronics operate in harsh environments, components must have rugged packaging and a long lifespan.
-Subject to large temperature variations
Military-grade components must be able to operate within a wide temperature range, from cold to hot. The temperature range for military components is -55°C to 150°C.
-Fine pitch components
Military components may require compact placement and operating spaces. These components can be BGA (Ball Grid Array), FBGA (Fine Pitch Ball Grid Array), etc. Therefore, military PCB components should be fine pitch.
military pcb assembly
Design of PCBs for Military
Various factors must be carefully considered when designing military PCBs, which must be highly reliable and robust with no margin for error. To design high-quality military PCBs, we should follow these steps:
- Routing
Typically, we increase the circuit density of the PCB when designing for military. This reduces the PCB's size and allows for efficient separation of circuits according to their function. We also ensure the proper distribution of components to achieve uniform wiring density. We pay attention to noise tolerance, signal transition times, different logic levels, and logic interconnections.
-Electromagnetic compatibility (EMC)
EMC (electromagnetic compatibility) is a priority when designingPCBs for military applications. While most of the PCBs we manufacture operate at high frequencies, military equipment operate in environments with high electromagnetic interference (EMI). Therefore, when creating a PCB layout, we consider factors such as grounding, emission noise suppression, crosstalk, and interference immunity.
-Higher Precision
Military PCB assembly requires a higher level of precision than conventional PCB assembly using standard processes. For instance, we clean PCBs with deionized water to prevent defects. We use lift-off or nano SMT stencils to deposit solder paste onto the PCB.
Conclusion
Military PCB assembly involves manufacturing high-performance electronics for defense applications. It requires high reliability, robustness, precision, and a long lifespan. PCBs, components, and design have stringent requirements for military PCB assembly. iPCB offers high-quality military PCB assembly at competitive prices. If you are interested in working with iPCB, please contact us by sales email.