Base material is one of the key points that related to final PCB quality espcially talking multilayer PCB. The quality of base material is mostly subject to it’s price.
Here are there are many unknown or local brand material with low prices but unstable quality(such as delamination for multilayer PCB assembly and voltage leakage for final functional PCB),some of them even not certificated by UL.
Weller: No matter that it is prototype PCB or mass production,unless customer’s prices pressure to use poor quality base material, or else We only use internationally known base material such as Shengyi, ITEQ,Nanya,Kingboard,Rogers, etc. All base materials WELLER used is certificated by UL, rather than other suppliers who use some inferior grade of material which is out of standard of UL.