IPC-4101 defines the standard for rigid laminates. It gives reasonable tolerances and target values for primary characteristics as to mitigate the effect of changing vendors. However, even under this specification there will be some variation from manufacturer to manufacturer on material performance, but these variations should not be any greater than the variation from fabricator to fabricator using the same material. Jeffrey A. McGlaughlin Sr. PCB Designer Battelle Memorial Institute Columbus Ohio [log in to unmask] -----Original Message----- From: Cates, Thomas [SMTP:[log in to unmask]] Sent: Wednesday, 15 March, 2000 17:38 To: [log in to unmask] Subject: [DC] Broard mat'l standards Hi - I'm a PWB designer and I need to convince some engineers I work with that we do not need to specify brand names of the FR-4 board material. They feel that since they tested the physical properties of a certain brand of FR-4 that we need to call that brand out in the FAB drawing note. In one case the company is no longer in business. I maintain that we will be safe and more flexible if we call out "Epoxy-Glass Laminate FR-4..." Is FR-4 made to some industry standard? If so how can I get a copy of this standard so I can prove my point once and for all? -thanks Thomas Cates Intermec - Amtech Systems Division