Learning Requirement Set-Up in PCB Design
Set-Up is the first step of PCB design, which includes the determinations of manufacturing processes and requirements. You’d better learn the requirements of set-up in PCB design if you want to get a satisfactory PCB. Then what requirements should the set-up of PCB design have?
Tg and Heat
The specify Tg and heat is the first requirement of set-up in PCB design. Commonly speaking, the thermal gradient (Tg) refers to the temperature value in which a material begins to lose stability or even get damage. Actually, the Tg is not only determined by the environment, but also by the PCB numbers and assembly processes the boards go through. Additionally, the material Tg should be specified if the material is not determined according to IPC standard. This ensures the material won’t delaminate during auto assembly period.
Copper Thickness
Apart from the Tg specification, the copper thickness is also the requirement of set-up in PCB design. The tolerance for all copper thickness needs to be specified if not set in IPC specification, and should be placed in a note. For all layers, the copper thickness tolerance shall be +/-.002’’ [.0508].
Overall Thickness
The Overall Thickness is decided by manufacturers. A particular thickness the designer requires should be added in notes. Thickness tolerance for the regular manufacturers is +/-10%, and this value would change under different technology and material conditions. As the overall tolerance is addition of all the materials tolerance, namely, the material tolerance is cumulative. Hence, the less or thinner board enjoys a smaller tolerance range.
