PCBA mechanical performance requirements refer to the ability of the printed circuit board assembly to withstand various mechanical stresses (such as vibration, impact, bending, and torsion) during transportation, installation, and use without damage, deformation, or failure of components and solder joints. These requirements are crucial for ensuring the reliability and service life of electronic products, especially for products used in harsh environments such as automotive, aerospace, and industrial control. One of the core mechanical performance requirements is the bending strength of the PCB substrate and the assembly. The PCB substrate (usually FR-4, aluminum-based, or flexible materials) must have sufficient bending strength to withstand the bending forces generated during installation (such as inserting the PCBA into a housing) and use. For example, flexible PCBs (FPC) used in wearable devices need to have excellent bending fatigue resistance, which can withstand repeated bending without cracking or breaking the traces.

Another important mechanical performance requirement is the adhesion strength between the PCB copper foil and the substrate, as well as between the components and the PCB. The copper foil adhesion strength ensures that the traces do not peel off from the substrate under mechanical stress, which is usually measured by the peel strength test (expressed in N/mm). Poor adhesion strength can lead to trace peeling, resulting in open circuits and system failure. For components mounted on the PCBA, the adhesion strength between the component body and the PCB (usually achieved through solder joints or adhesive) must be sufficient to withstand vibration and impact. For example, in automotive electronic products, the PCBA is subject to continuous vibration during vehicle operation, and insufficient component adhesion can lead to component detachment or solder joint failure. Additionally, the mechanical strength of the solder joints is a key requirement: solder joints must have sufficient shear strength and tensile strength to withstand mechanical stress without cracking or breaking. Solder joint strength is affected by factors such as solder material, soldering temperature, and solder joint shape.

In addition to the above requirements, PCBA mechanical performance also includes requirements for dimensional stability, torsion resistance, and impact resistance. Dimensional stability refers to the ability of the PCBA to maintain its original size and shape under changes in temperature and humidity, as well as under mechanical stress. Poor dimensional stability can lead to component misalignment, solder joint fatigue, or interference with other components in the product. Torsion resistance requires that the PCBA can withstand a certain degree of torsion without damage to the traces or components, which is particularly important for PCBs used in devices that may be twisted during use. Impact resistance refers to the ability of the PCBA to withstand sudden impact forces (such as drops or collisions) without component damage or solder joint failure. For example, consumer electronic products such as mobile phones and tablets need to have good impact resistance to ensure that the PCBA remains intact when the product is dropped. These mechanical performance requirements must be considered during the PCB design (such as selecting appropriate substrate materials and component packaging) and production process (such as optimizing soldering parameters and using reinforcement measures) to ensure the reliability and durability of the PCBA.