One thing you should definitely verify is that the "non-standard" issue is related solely to inventory issues. There are some shops that don't run unbalanced copper weights. It's not that it's rocket science but they just haven't invested the effort to doing so. If this is the case and they don't really have process for doing this, you're looking at a completely different issue. If you've got a shop that is doing this for the first time, I'd ask for some data verifying that they are doing it correctly. From an inventory perspective, this combination of copper clad should be readily available. It's not used as commonly as some of the other clad combinations which can complicate availability. Let's face it, there are so many different materials available in so many thicknesses, that no shop can afford to keep inventory of every possible combination of clad materials. But if you use only a few different cores with this combination of clad weights, you should be able to work with the fabricator to stock adequate levels for your needs. It sounds there's a disconnect between what you and your fabricator consider "standard". Perhaps your Purchasing department can help you get calibrated. > ---------- > From: Takach, Lou J[SMTP:[log in to unmask]] > Reply To: TechNet E-Mail Forum.;Takach, Lou J > Sent: Monday, March 18, 2002 4:11 AM > To: [log in to unmask] > Subject: [TN] Non-Standard material > > Good Morning Technetters... > > I need your input / advice. Our manufacturing facility has recently > (within > a year or so...) switched to a new PCB fabricator. I'm now starting to get > complaints from manufacturing that our fabricator is having trouble > obtaining the 'non-standard' material that we are specifying. First of > all, > I don't believe that I'm specifying non-standard material, this is where I > need your input. Most of our boards are multi-layer, usually 4 to 6 layers > and we use FR4. We typically specify 2-oz copper on the internal power and > ground layers and sometimes 1-oz copper for the outer signal layers. Is > this > non-standard? The fabricator says that they typically don't stock 1 over 2 > copper. Maybe I'm missing something but I thought that the stackup could > be > made of individual copper sheets of various copper weights as long as the > layer sequence was balanced. > > All comments welcome... > > Lou > > -------------------------------------------------------------------------- > ------- > Technet Mail List provided as a free service by IPC using LISTSERV 1.8d > To unsubscribe, send a message to [log in to unmask] with following text in > the BODY (NOT the subject field): SIGNOFF Technet > To temporarily halt delivery of Technet send e-mail to [log in to unmask]: > SET Technet NOMAIL > To receive ONE mailing per day of all the posts: send e-mail to > [log in to unmask]: SET Technet Digest > Search previous postings at: www.ipc.org > On-Line Resources & Databases > > E-mail Archives > Please visit IPC web site http://www.ipc.org/html/forum.htm for additional > information, or contact Keach Sasamori at [log in to unmask] or 847-509-9700 > ext.5315 > -------------------------------------------------------------------------- > ------- > --------------------------------------------------------------------------------- Technet Mail List provided as a free service by IPC using LISTSERV 1.8d To unsubscribe, send a message to [log in to unmask] with following text in the BODY (NOT the subject field): SIGNOFF Technet To temporarily halt delivery of Technet send e-mail to [log in to unmask]: SET Technet NOMAIL To receive ONE mailing per day of all the posts: send e-mail to [log in to unmask]: SET Technet Digest Search previous postings at: www.ipc.org > On-Line Resources & Databases > E-mail Archives Please visit IPC web site http://www.ipc.org/html/forum.htm for additional information, or contact Keach Sasamori at [log in to unmask] or 847-509-9700 ext.5315 ---------------------------------------------------------------------------------