Home 9 Materials 9 FR4


FR-4 is a manufacturing material with strength almost equal to steel and lightweight. It is a perfect fit for making parts for the electrical marine industry since it is flame retardant, has a negligible water absorption coefficient, and is machinable.

FR4 At a Glance

Process compatibilityApplicationsTolerancesWall ThicknessMax Part SizeStrengthsLead TimePrice
CNC Mill
CNC Lathe
Variety of shapes for use in electrical circuit boards with a high degree of accuracy.Not lower than ±0.125mm (±0.005″) based on the drawing ( ISO 2768)Minimum 0.80 mm  (0.03″), but this can change depending on the proportion of the wall thickness to the linear dimension.200 x 80 x 100 cmExcellent hardness, strength almost equal to steel and lightweight.Minimum 3 days. Not more than 10 days; for all complex parts.$$

Introduction to FR4

FR refers to flame retardant, rigid material with excellent toughness. FR- 4 is created using particular chemicals that slow down or stop the spread of flames. Therefore it is appropriate for a variety of marine and electrical applications.

Due to great machinability, FR-4 can be manipulated into various shapes for use in electrical circuit boards. It has an almost negligible water absorption capacity (< 0.10%). FR-4 also offers good electrical properties and is very good for the impedance consideration of circuits.