FR4 Core and Prepreg Thicknesses — What Is Actually Available?
·1599 words·8 mins
When engineers search for standard FR4 thicknesses, they usually expect a simple answer. Instead, they often encounter conflicting information.
One source lists a 0.10 mm core. Another shows 0.136 mm. A third refers to a 1080 prepreg with a thickness of 0.075 mm, while a supplier datasheet lists an entirely different value.
The confusion arises because several different concepts are being mixed together:
Core thickness Finished core thickness Prepreg thickness Pressed dielectric thickness Glass style Resin content Lamination behaviour All of these values are related, but they are not the same thing.