TWO definition must know when purchase high quality PCB

TG is the most important parameters to the high quality PCB

First of all, we should introduce what is TG?
The Glass Transition Temperature (Tg) is one of the most important properties of any epoxy and is the temperature region where the polymer transitions from a hard, glassy material to a soft, rubbery material.

Second is why TG so important to the PCB, or what is the relationship between TG parameter and PCB price?
If you know some steps of the PCB assembly process, you will find this is the most important parameters.
Because a high TG is a guard against barrel cracking and pad fractures during soldering operation.
Error Tg PCB board means assembly process will be full.

TCE is the most complex parameters in conventional PCB purchase process

What is Coefficient of thermal expansion (Tce)?
TG is simpler than TCE definition.
The coefficient of thermal expansion is defined as the fractional increase in the length per unit rise in temperature.
From this TCE definition, we know the material width or length will change by increase temperature.

During assembly metal core PCB process, there were many details to notice.
The first of all should notice is PCB board is exposed on the air, SMD assembly process have increased temperature of the surface and inter of PCB board, and increase temperature shocks complex than typical through hole process.
So you purchase a PCB board must meet high temperature and TCE.

The density factor also must consider during the purchase PCB process
Now the board has become more layered, and increase in the lead density cause the designer to use more and more 2 layers.
You know multilayer PCB has a more complex design process.
This can be a particular problem with regard to Z-axis expansion of the material since this induces stress in the copper-plated holes, and becomes a reliability concern.
TWO definition must know when purchase high quality PCB

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