The Influence of PCB Thickness and Copper Thickness on PCB Design
The thickness and copper thickness are mainly considered in the fabrication and blanking of circuit boards. For boards with a thickness greater than 0.8MM, the standard series is 1.0 1.2 1.6 2.0 3.2 MM. If the thickness is less than 0.8MM, it is not a standard series. The thickness can be determined according to needs, but the thickness often used is 0.1 0.15 0.2 0.3 0.4 0.6MM. This material is mainly used for the inner layer of multilayer boards.
When designing the outer PCB, pay attention to the selection of plate thickness. For production and processing, the thickness of copper plating, solder resistance, surface treatment (tin spraying, gold plating, etc.), characters, carbon oil, etc. should be increased. The actual production of sheet metal plate will be 0.05-0.1MM thick, and the tin plate will be 0.075-0.15MM thick. For example, when the finished product is required to have a thickness of 2.0 mm in PCB design, when the 2.0mm sheet is normally selected for blanking, the thickness of the finished product will reach 2.1-2.3 mm in consideration of the plate tolerance and processing tolerance. If the PCB design must require that the thickness of the finished product should not be greater than 2.0 mm, the plates should be made of 1.9mm unconventional plates. The double-layer PCB circuit board processing plant needs to temporarily order from the plate manufacturer, and the delivery cycle will become very long.
During the fabrication of inner layer, the thickness after lamination can be adjusted through the thickness and structural configuration of the semi cured sheet (PP). The selection range of core plate can be more flexible. For example, the thickness of finished plate is required to be 1.6 mm, and the selection of plate (core plate) can be either 1.2 mm or 1.0 mm. As long as the thickness of laminated plate is controlled within a certain range, the thickness requirements of finished plate can be met.
In addition, there is the issue of thickness tolerance. PCB designers should consider the thickness tolerance of double-layer PCB after processing while considering the product assembly tolerance. The finished product tolerance is mainly affected by three aspects, namely, the incoming material tolerance, lamination tolerance and outer layer thickening tolerance. Several conventional plate tolerances are provided for reference: (0.8-1.0)± 0.1 (1.2-1.6)± 0.13 2.0± 0.18 3.0± 0.23 Lamination tolerance shall be controlled within± according to different layers and plate thickness; (0.05-0.1) MM. Especially for boards with board edge connectors (such as printed plugs), the thickness and tolerance of the board shall be determined according to the requirements for matching the connectors.
The problem of copper thickness on the surface is that the hole copper needs to be chemically plated and plated. If no special treatment is made, the copper thickness on the surface will be thickened when the hole copper is thickened. According to IPC-A-600G standard, the thickness of small copper coating is 20um for grade 1 and 2, and 25um for grade 3. So in
Manufacturer of pcb circuit boardDuring fabrication, if the copper thickness is required to be 1OZ (less than 30.9um), sometimes HOZ (less than 15.4um) will be selected for blanking according to the line width/line spacing, and the allowable tolerance of 2-3um will be reduced to 33.4um. If 1OZ blanking is selected, the copper thickness of the finished product will be reduced to 47.9um. Other copper thickness calculations can be deduced in turn.
Release time：2022-12-13
