Define the Thickness of a PCB
The thickness of a PCB affects its performance, reliability, and manufacturability. The right choice is essential for a particular design and application. Thicker boards can withstand physical stress, vibration, and other environmental factors better. However, they are more expensive than thinner alternatives.
Several factors influence the standard thickness of a pcb. Depending on the client’s assembly requirements and choice of fabrication services, the thickness can vary. Some of the most important factors include copper thickness, board materials, and the number of layers. The operating environment, signal types, and via type also play a role in PCB thickness.
The PCB’s core layer is called the substrate. This is typically a rigid insulating material like FR-4, but can also be flexible and foldable. It’s used to bind all the other components on the circuit board. There’s usually one conductive layer laminated to the substrate, but on double-layer and multilayer PCBs, there are more.
How Do You Define the Thickness of a PCB?
In addition, the thickness of the copper traces and the thickness of the dielectric layers also impacts the overall thickness of a PCB. In general, thicker traces are more reliable than thinner ones because they can handle greater currents. However, these characteristics aren’t always relevant to the design of a PCB. It’s also necessary to take into account the overall height requirements of components and connectors when choosing a thickness.
While the IPC-6012 guidelines and rules set a minimum PCB thickness of 1.6mm, this is not a hard-and-fast rule that is enforced across the industry. The thickness of a PCB depends on its environment, spatial limitations, and anticipated lifespan.
When determining the thickness of a PCB, it’s also crucial to consider the manufacturing processes that will be applied. For instance, the thickness of a PCB impacts its ability to be scored and routed into individual boards. Similarly, the thickness of a PCB influences how it can be depaneled.
The PCB’s thickness can also be affected by the materials it’s made of and how they respond to thermal expansion and contraction. It’s also a factor that influences the amount of copper needed to conduct the necessary electrical functions.
The actual PCB thickness is calculated by adding the nominal thicknesses of all the layers that make up the build-up (laminate and copper). The total thickness does not include finishes, solder mask, or silkscreen. Consequently, PCB manufacturers do not guarantee exact thicknesses, but will instead quote a maximum tolerance of 10% of the calculated thickness.
For this reason, it’s critical to work with the manufacturer early on in the project to ensure that the PCB’s thickness meets all required specifications. This ensures that the finished product works correctly. To get the best results, you should always use a trace width calculator to calculate and specify the desired PCB thickness. This will prevent the final product from being too thin or too thick, which can cause problems during assembly. This is especially important for high-reliability applications.