Purpose of prepeg and core

[srilu]

prepeg

In PCB manufacturing
I know that core (laminate..FR4 etc.,) acts as insulator b/w two copper foils.
But what is pre-peg and what is its purpose ?

regards,
Srilu

 

[sigint]

prepeg pcb

Prepreg is a non-cured glass/epoxy sheet that acts as the glue during multilayer lamination - a simplified example is that the epoxy between the copper sheets in a piece of core material is cured prepreg.

SiGiNT

 

[amjad]

pre peg

Core is the dielectric material between two copper layers which forms a Laminate, & prepreg is the dielectric material which is used to bond thes laminates

 

[amjad]

prepeg in pcb

FYI:

You cannot call the laminate as insulator. It has dielectric constant and provides capacitance by which return current to pass from signal to gnd.