High TG PCB board is basically defined as the high heat resistance in a PCB raw material or a PCB designed to withstand high temperatures, High TG is generally greater than 170°C. Therefore, a PCB with TG greater or equal to 170°C is a high TG PCB. When you talk about one of the most important properties of any epoxy, it is the Glass Transition Temperature (TG).

Furthermore, the Glass Transition Temperature is also the temperature area where the polymer transitions from hard, glass-like material to a soft rubber-like material. It is essential for the high TG PCB material to be flame-resistant; it should not be vulnerable to heat or a specific temperature; it can only get soft. The temperature point of the circuit board is called the Glass Transition Temperature (TG) hence a high TG PCB is one whose printed circuit board is made to withstand extremely high temperatures.

Also, during lamination, the higher the glass transition temperature point, means the higher the temperature requirement. High-temperature requirements during lamination will cause the boards to be crisp and hard, which tends to affect the electrical properties of the board hole.

However, ordinary PCB materials at high temperatures will be subject to some phenomena like melting, deformation and others, it’s electrical and mechanical properties would even decline as well. Fr4 TG is generally 130 – 140 Centigrade, high-TG is also greater than 170 degrees whiles the moderate TG is usually higher than 150-160 Centigrade. The performance of PCB moisture resistance, heat resistance, stability, chemical resistance, and other characteristics during High TG PCB fabrication depends directly on how high the glass transition temperature is.

FR4 refers to the grade of Epoxy Glass material, and TG refers to the glass transition temperature. When a given temperature can reach its melting point, it merely means the temperature has exceeded the glass transition temperature value, hence the Printed Circuit Board material’s state will be changed from glassy to liquid, which in turn also affects the function of PCB. The value produced is related to the stability of the PCB dimensions.

And, a glass transition temperature that is greater or equal to a 170-degree-Celcius PCB is known as a high glass transition temperature printed circuit board (PCB). As a result of the rapid development and advancement of the electronics industry, high glass transition temperature materials are widely used in communication equipment, computer, instrument, precise apparatus, and many others.

What is FR4?

FR4 is the code name designated for a grade of flame-retardant fiberglass reinforced epoxy material; hence FR4 PCB gives an as much higher level of resistance to heat than ordinary PCB. FR4 circuit boards are classified into four divisions and are determined by the number of copper trace layers that are found in the material. They include;

  •  The single-layer PCB or single-sided PCB
  •  Double-sided PCB or Double-layer PCB
  •  Four or more than ten layers of PCB or Multilayer PCB
Characteristics of high TG PCB material
  • It has a high resistance to heat
  • Lower Z-axis CTE.
  • Excellent thermal stress resistance
  • Excellent PTH reliability
  • High thermal shock resistance.

High-TG PCB Application
The high TG PCB board has various uses in well-known areas, some of which include;

  •  Automotive equipment
  •  Computers
  • Consumer equipment
  •  Industrial equipment
  • Communication equipment

Materials used for high- TG PCBs manufacturing

  • FR4 S1141
  • FR4 S100 – 2M
  •  IT180
  • Rogers 435OB
Material S1141 (FR4)
TG (DSC, °C) 175
Td (WT, °C) 300
CTE-z (ppm/ °C) 55
Td260 8
Td288 (min)
Material FR4 S100 - 2M
TG (DSC, °C) 180
Td (WT, °C) 345
CTE-z (ppm/ °C) 45
Td260 60
Td288 (min) 20
Material IT180
TG (DSC, °C) 180
Td (WT, °C) 345
CTE-z (ppm/ °C) 45
Td260 60
Td288 (min) 20
Material Rogers 435OB
TG (DSC, °C) 280
Td (WT, °C) 390
CTE-z (ppm/ °C) 50
Td288 (min)
Solder Mask (Temperature Resistance)

Solder Mask also known as solder layer, solder stop mask or solder resist is a thin layer of polymer in a form of a lacquer that is usually used on the copper traces of a high TG PCB board to serve as a protection from oxidation and stops solder bridges from forming in between closely spaced solder pads. An accidental electrical connection between two conductors through a small mass of solder can form a solder connection.

Moreover, a solder Mask usually is green but is recently taking on a rainbow of colors. It requires 1000°C/W for the PCB to air, which only means that the copper on the other side would dissipate almost as much heat into the air even when you have copper on one side of the PCB. And an interior layer that has a direct metal connection will also be almost as active as a surface layer.

Equally important, the glass transition temperature of the PCB shows the point where the PCB material begins to transform. If it’s operating temperature goes beyond its designated TG value, the board would start to experience some transformations changing it from it’s solid-state to a liquid state, which would have severe effects on its ability to function.

Again, ordinary PCBs are usually fabricated with materials that offer a TG value of at least 140°C, and such values can withstand a 110°C operating temperature. It may not exactly be suitable for extreme temperature applications like industrial, high-temperature electronics or automotive. In cases like this, it is advisable to use a PCB that is made from FR4 material.

High TG PCB Specification of MOKO Technology
Min. Hole Size 0.2mm
Copper Thickness 1OZ / 2OZ
Min. Line Width 0.1mm or 4mil
Board Thickness 0.8-1.6mm
Base material FR4
Min. Line Spacing 0.1mm
Surface Finishing HALS / HALS OSP
Product name Electronic PCB Design
Application Consumer Electronics
Certificate CE FCC
Solder Mask Color Black. Red. Yellow. White. Blue. Green
Type Electronic Board
Material FR4 CEM1 CEM3 Hight TG

Finally, MOKO Technology is now a non-stop and positive force in PCBA manufacturing for complete PCB assembly services since 2006. As the EMS world is rapidly changing, MOKO technology has redefined itself permanently to provide nothing but superior production services. MOKO technology PCB assembly satisfies and exceeds its customer’s expectations. In terms of price, quality, and delivery.

If you are looking to get the best-embedded systems or a high TG PCB manufacturer, look no further. You can use MOKO technology to design your high TG PCB boards. Regardless of the complex nature and scope of specific PCB applications, MOKO technology has the technical expertise and the best High TG PCB materials to develop a customized Printed Circuit Board (PCB) that would satisfy your particular demands.

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