During the 20th century is when the standards of PCB were defined starting from a sheet frame to when Albert Hanson developed flat foul conductors insulated in multiple layers. The boards had a simple design with a single board with many layers placed together. Today, PCB’s are either single-sided (with one copper layer), two/double sided (two copper layer with a substrate layer between them) or multi-layer (multiple layers of the two-sided PCB).
The typical PCB thickness is 0.063inches or 1.57mm; it is a standardized level defined from the past. That is because, during the plywood industry, 0.063″ was the thickness of the plywood sheets used as substrates for electronic devices which included PCB’s.
When multiple layer PCBs started developing, the thickness of the connectors between the boards had to match. Therefore, the level of thickness became a significant variable and there was a requirement for a standard level of the copper used as layers on the plate edges. In turn, 0.063” became the Standard PCB Thickness.
Nevertheless, there is a general thickness range of 0.008 inches to 0.240 inches between which you can choose depending on the application or usage area. It is therefore essential that you communicate requirements for the appropriate PCB thickness size.
PCB board thickness
The width of the board is reliant on the insulating layer and the content of its material. Early in the development of PCBs, the layers, top, and bottom were made of Bakelite, and the resultant thickness was 0.0065″.
Over time, use of better substrates other than plywood started being used. For instance, epoxy or the paper reinforced phenolic resin, are among substrates used between layers of copper foil. Consequently, the use of lighter materials in addition to the lack of use of the edge connectors, the board thickness is at times below 0.0065”.
PCB copper thickness
Copper being the dictator of a PCB’s functionality and area of application, its thickness has an essential role in achieving the standard PCB thickness. Its measurement is usually an ounce (oz). It is achieved by spreading an ounce of copper evenly over square foot area which this results to 1.37 mils (1.37 thousandths of an inch).
Usually, PCBs are manufactured with the 1 oz of copper. Also, it is the presumed thickness by manufacturers when the designer does not give them specific measurements.
However, if the current that is to pass through the PCB will require more than an ounce of copper, a manufacturer can add the weight of the copper or the width of the trace. However, increases in price and not just because of the increased copper but also, processing thicker copper is more challenging and requires more time.
PCB trace thickness
The PCB trace thickness is the thickness determined by the designer, and it is one of the essential parameters in PCB designing. It is specified in the designer Garber files to prevent overheating or damaging of the PCB. When the current flows or increases, the copper traces start heated and ultimately PCB temperature rises. When the temperature exceeds the limit of the PCB, it starts getting damaged. Therefore, trace should be thick enough to allow higher current passage without affecting the average temperature of the PCB.
So how is the PCB trace thickness determined? The amount of current passing through the PCB is compared to the increase in temperature. The width that can handle the increase in temperature from the average operating temperature to the maximum operating temperature is the trace thickness.
The task of calculating the trace width would be tiresome. Designers, therefore, use a PCB width calculator that provides the appropriate width for current to pass through without causing any damage to the PCB. The resultant thickness has wide internal layers due to storage of more heat as the external layers transfer their heat through convection to them.
It is recommendable to use internal trace width for all traces