Reliability of PCB Printed Circuit Boards
A pcb printed circuit board is the foundation of a fully functional electronic device and needs to be able to withstand a wide range of environmental, mechanical and electrical stresses. This includes passing a variety of testing and inspection processes that ensure the PCB can safely be deployed in an end product for an extended period of time.
Achieving a high level of reliability is challenging as it is impossible to test all possible scenarios for failure in the real world. The good news is that a careful design approach that follows best practices in conjunction with utilizing tools like Monte Carlo simulation, smoke analysis and other PCB modeling and analysis software can help achieve the required level of reliability for a given project.
One of the most critical factors that influences the reliability of a pcb printed circuit board is temperature. This is due to the fact that a pcb must be able to tolerate a variety of temperatures during the manufacturing and assembly process. As well as the operational temperatures it will be subjected to once it is in service.
Factors That Influence the Reliability of PCB Printed Circuit Boards
Another factor influencing the reliability of a pcb has to do with the material that it is made from. The material needs to be able to withstand varying temperature and thermal expansion/shrinkage rates. It also must have a similar CTE rate to copper in the X, Y and Z directions, as mismatches between these can cause plated through hole walls to rupture and result in an electrical discontinuity in the circuit.
The surface finish of a pcb plays an important role in its ability to resist heat and facilitate soldering. For example, finishes like Electroless Nickel Immersion Gold (ENIG) have flat and oxidation-resistant surfaces that promote good wetting of the solder paste during the assembly process, while other finishes have organic solderability preservers that keep the copper conductive layer soft, allowing it to accept more solder.
In addition, a pcb must be fabricated using materials with high corrosion resistance. This is especially important for environments with salty air or moist conditions, which can degrade the materials causing them to corrode and potentially damage the circuit board.
Finally, a pcb must be designed to withstand various mechanical stresses including drop tests. This is typically achieved by routing traces over the areas that are most important for the performance of the circuit board. These will include the power nets, any impedance-controlled nets and noise-sensitive nets such as low-level analog signals. In addition to following proper route rules, designers can use tools such as Altium Designer to simplify the routing process by highlighting nets and offering interactive routing features. This can help reduce errors and speed up the routing process.
