Lead-free HASL Double Sided PCB with FR4

What is TG in PCB?

The TG in the PCB board material means the temperature resistance value.
The higher the Tg point, the higher the temperature requirements when pressing the plate, and the pressed plate will also become hard and brittle, which will affect the quality of mechanical drilling to a certain extent (if any) in the subsequent process.
The general Tg sheet is above 130 degrees, the High-Tg is usually above 170 degrees, and the medium Tg is above 150 degrees. The Tg of the substrate has been improved, including heat resistance, moisture resistance, chemical resistance, stability, etc., and the function of the printed board will continue to improve.
The higher the TG value, the better the heat resistance of the board, especially in the lead-free tin spray process, high Tg applications are more common.

The higher the TG value, the better the heat resistance of the sheet, especially in the lead-free process, high TG applications are more.
The glass transition temperature is one of the characteristic temperatures of high molecular polymers. Taking the glass transition temperature as the boundary, polymers exhibit different physical properties: below the glass transition temperature, the polymer material is plastic; above the glass transition temperature, the polymer material is rubber.
From the perspective of engineering applications, the glass transition temperature is the upper limit of the temperature of engineering plastics and the lower limit of the use of rubber or elastomers.
With the rapid development of the electronics industry, especially the development of electronic products represented by computers, the development of high functions and high multilayers requires PCB substrate materials to have higher heat resistance, which is an important guarantee.
The emergence and development of PCBA Manufacturing's high-density mounting technology represented by SMT and CMT has made HDI PCBs increasingly inseparable from the support of high heat resistance of the substrate in terms of small aperture, fine wiring and thinning.