EDCOR uses FR-4 PCB material for all of thier printed circuit boards.

Most printed circuit boards are manufactured using glass-reinforced epoxy laminate as the substrate. While there are a wide variety of laminates available on the market, FR-4 is both versatile and well-accepted as a standard material for PCB manufacture. FR-4 functions well as an electrical insulator, and has a good strength-to-weight ratio, and is flame resistant.

EDCOR uses single and double sided PC boards, ranging from 0.032" to 0.062" thickness. EDCOR's PC boards have a nickel solder flow. All materials are RoHS compliant.

## Properties

Typical physical and electrical properties of FR-4 are as follows. LW (length wise, warp yarn direction) and CW (cross wise, fill yarn direction) refer to the fiber orientations in the plane of the board (in-plane) that are perpendicular to one another. The through-plane direction is also referred to as the z-axis.

Parameter | Value |
---|---|

Speciļ¬c gravity/density |
1.850 g/cm^{3} (3,118 lb/cu yd) |

Water absorption |
−0.125 in < 0.10% |

Temperature index |
140 °C (284 °F) |

Thermal conductivity, through-plane |
0.29 W/m·K,^{[1]} 0.343 W/m·K^{[2]} |

Thermal conductivity, in-plane |
0.81 W/m·K,^{[1]} 1.059 W/m·K^{[2]} |

Rockwell hardness |
110 M scale |

Bond strength |
> 1,000 kg (2,200 lb) |

Flexural strength (A; 0.125 in) - LW |
> 440 MPa (64,000 psi) |

Flexural strength (A; 0.125 in) - CW |
> 345 MPa (50,000 psi) |

Tensile strength (0.125 in) LW |
> 310 MPa (45,000 psi) |

Izod impact strength - LW |
> 54 J/m (10 ft·lb/in) |

Izod impact strength - CW |
> 44 J/m (8 ft·lb/in) |

Compressive strength - flatwise |
> 415 MPa (60,200 psi) |

Dielectric breakdown (A) |
> 50 kV |

Dielectric breakdown (D48/50) |
> 50 kV |

Dielectric strength |
20 MV/m |

Relative permittivity (A) |
4.8 |

Relative permittivity (D24/23) |
4.8 |

Dissipation factor (A) |
0.017 |

Dissipation factor (D24/23) |
0.018 |

Dielectric constant permittivity |
4.70 max., 4.35 @ 500 MHz, 4.34 @ 1 GHz |

Glass transition temperature |
Can vary, but is over 120 °C |

Young's modulus - LW |
3.5×10^{6} psi (24 GPa) |

Young's modulus - CW |
3.0×10^{6} psi (21 GPa) |

Coefficient of thermal expansion - x-axis |
1.4×10^{−5} K^{−1} |

Coefficient of thermal expansion - y-axis |
1.2×10^{−5} K^{−1} |

Coefficient of thermal expansion - z-axis |
7.0×10^{−5} K^{−1} |

Poisson's ratio - LW |
0.136 |

Poisson's ratio - CW |
0.118 |

LW sound speed |
3602 m/s |

SW sound speed |
3369 m/s |

LW Acoustic impedance |
6.64 MRayl |

[1] Azar, K; Graebner J. E. (1996). "Experimental Determination of Thermal Conductivity of Printed Wiring Boards". *Proceedings of the Twelfth IEEE SEMI-THERM Symposium*: 169–182.

[2] Azar, K; Graebner J. E. (1996). "Experimental Determination of Thermal Conductivity of Printed Wiring Boards". *Proceedings of the Twelfth IEEE SEMI-THERM Symposium*: 169–182.