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Material FR-4

 

The materials covered by the specification FR-4 classification NEMA, is most often used for the production of double-sided and multilayer printed circuit boards.

Standard FR-4 is a composite material based on glass fibers (glass fiber). Standard FR-4 of 1.6 mm thickness is composed of eight layers ("prepregs") fiberglass. The central layer is usually the manufacturer's logo and its color reflects the Fire class of the material: red & ndash; & nbsp; UL94-V0, blue & ndash; & nbsp; UL94-HB.

Usually, FR-4 is transparent, standard green solder mask defined by the color applied to the finished printed circuit board.

So, FR-4 is the most common worldwide base material for the production of double-sided and multilayer printed circuit boards, as well as being for the production of single-sided printed circuit boards with high requirements for mechanical strength.

FR-4 material characteristics:

PCB material

Properties

 

The test conditions

Units of measure

Values

 

The surface resistance

high humidity

F

Megohm

> 1000000

 

 

high temperature

E-24/125

 

 

 

Volume resistance

high humidity

F

Megohm * cm

> 10000

 

 

high temperature

E-24/125

 

> 1000

 

Dielectric breakdown

D-48/50 + D-0.5/23

KV

> 40

 

The dielectric constant at 1 MHz

C-40/23/50

 

< 5.4

 

The dielectric loss tangent at 1 MHz

C-40/23/50

 

< 0.035

 

Дугостойкость

D-48/50 + D-0.5/23

sec

> 60

 

Прочность на разрыв при слое меди 35 мкм

усредненный

A

N/mm

> 1.4

 

 

после термического воздействия

A

N/mm

> 1.4

 

The requirement for soldering

288 С, 20 сек

 

not stratified

 

 

288 С, 20 сек

 

 

 

Flexural strength

longitudinal

A

MPa

> 410

 

 

transverse

A

MPa

> 340

 

Water Absorption

E-1/105 + des + D-24/23

%

0.1-0.77

< 0.8

 

 

 

 

0.78-3.2

< 0.35

 

 

E-1/105 + des

%

 

 

Flammability

 

A & E-1/105 + des

94V-0

 

Dimentions stability

E-4/105 + des + E-2/150

mkm/cm

+-4.92