PCB mechanical properties refer to the physical properties of printed circuit boards that allow them to change shape and resist force. The two most common threats to bending strength are excessive heat and direct physical force, but shock and vibration can also pose a threat. Some manufacturers measure these properties using Young’s modulus, which measures the stiffness of material.
FE analysis
A FE analysis of PCB mechanical properties is a method used to estimate the equivalent mechanical properties of a PCB. This technique involves evaluating five PCBs of different copper layers, thicknesses, and sizes. It employs a sine response analysis and various damping values to evaluate the PCBs’ mechanical properties.
The FE analysis of PCB mechanical properties can be performed by using commercial software to predict the mechanical behavior of a PCB. For example, it can be used to predict the thermal strains and warpage of a component. The temperature results are then used to predict the fatigue life of a solder joint.
Electrical strength
The electrical strength of a PCB is an important characteristic of a circuit board. This property determines the resistance of a PCB material to breakdown. PCB dielectrics typically have an electrical strength of 800 to 1500 V/mil. The value is measured by subjecting the PCB to high voltage pulses at standard AC power frequencies.
High-voltage PCBs are often used in products such as mains-powered power supplies, EV chargers, and inverters. The general rule is that boards above 100V require special rules for construction. This type of electrical field is called dielectric strength, and most PCBs are made of FR-4, which has a high dielectric strength.
Dielectric constant
Dielectric constant (Dk) is an important property of circuit boards and materials, and it relates to electrical properties such as impedance and signal integrity. Generally, a PCB material’s Dk value ranges from 3.5 to 5.5. This value changes with frequency, but it tends to be less variable on some materials than others. In circuits that operate at high frequencies, this property is very important.
Typically, a PCB’s dielectric constant varies according to the frequency at which it’s used. This characteristic is an indicator of signal integrity, which is a critical element for any electronic circuit. The higher the frequency, the lower the value of the dielectric constant. In general, the range for dielectric constant is 3.5 to 5.5, though the exact value may vary. If you’re using a PCB for high-frequency applications, you’ll want a material with a stable dielectric constant. This is to ensure safety and reliability.
Cavity coverage
Cavity coverage is a mechanical property of a printed circuit board, which refers to the physical space in the board that is not made up of metal. The cavity can be formed on a rigid PCB portion and can have one or more conductive surfaces. Cavity coverage is a critical consideration when determining PCB mechanical properties.
Cavity designs are common in multilayer printed circuit boards. These cavities are designed to reduce electrical losses and improve mechanical properties. They are compatible with high-performance laminates.
