The production of circuit boards mainly considers the board thickness and copper thickness. For boards with a thickness of more than 0.8MM, the standard series is: 1.0 1.2 1.6 2.0 3.2 MM, and the thickness of the sheet is less than 0.8MM. It is not considered a standard series. The thickness can be changed according to needs. The thickness is fixed, but often used: 0.1 0.15 0.2 0.3 0.4 0.6MM, this material is mainly used for the inner layer of multi-layer boards.

When designing the outer PCB, pay attention to the thickness of the board. The production and processing need to increase the thickness of copper plating, solder mask thickness, surface treatment (tin spraying, gold plating, etc.) thickness, characters, carbon oil and other thickness. The actual production of sheet metal will be thicker than 0.05-0.1 MM, the tin plate will be 0.075-0.15MM thicker. For example, when the PCB design requires a thickness of 2.0 mm for the finished product, and when the 2.0mm sheet is normally used for cutting, the thickness of the finished product will reach 2.1-2.3mm, taking into account the tolerance of the board and the processing tolerance. When it is not larger than 2.0mm, the plate should be made of 1.9mm unconventional plate material. The double-layer PCB circuit board processing plant needs to temporarily order from the plate manufacturer, and the delivery cycle will become very long.

When the inner layer is made, the thickness after lamination can be adjusted through the thickness and structure configuration of the prepreg (PP). The selection range of the core board can be flexible. For example, the thickness of the finished board is 1.6mm, and the choice of the board (core board) can be 1.2 MM can also be 1.0MM, as long as the thickness of the laminated plate is controlled within a certain range, the thickness of the finished plate can be met.

The other is the board thickness tolerance problem. PCB designers should consider the board thickness tolerances after the double-layer PCB circuit board is processed while considering the product assembly tolerances. The tolerances of the finished products are mainly affected by three aspects: the incoming sheet tolerance, the laminated tolerance and the outer layer. Thickening tolerance. Several conventional sheet tolerances are now provided for reference: (0.8-1.0)±0.1 (1.2-1.6)±0.13 2.0±0.18 3.0±0.23 The lamination tolerance is controlled within ±(0.05-0.1) according to different layers and thicknesses MM. Especially for boards with board edge connectors (such as printed plugs), the thickness and tolerance of the board need to be determined according to the requirements of matching with the connector.

The surface copper thickness problem, because the hole copper needs to be completed by chemical copper plating and copper electroplating, if no special treatment is done, the surface copper thickness will be thicker when the hole copper is thickened. According to the IPC-A-600G standard, the minimum copper plating thickness is 20um for level 1, 2 and 25um for level 3. Therefore, when the copper thickness is required to be 1OZ (minimum 30.9um) when the copper thickness is required for circuit board production, the cutting may sometimes Choose HOZ (minimum 15.4um) cutting material according to the line width/line distance, remove the allowable tolerance of 2-3um, the smallest can reach 33.4um, if you choose 1OZ cutting, the minimum thickness of the finished copper will reach 47.9um. Other copper thickness calculations can be deduced by analogy.