Vasile: You are a good guy to have on this list. Regards Rich ----- Original Message ----- From: "Vasile Surducan" To: "Microcontroller discussion list - Public." Sent: Sunday, June 11, 2006 4:31 PM Subject: Re: [EE:] Visually determining PCB layer count > On 6/12/06, Florian Voelzke wrote: >> Vasile Surducan wrote: >> > On 6/10/06, Rich Graziano wrote: >> > >> >>In my dumb way, I thought they were all compressed to the same >> >>thickness; >> > >> > >> > No way. The thickness is a matter of layer numbers and technology (ie >> > a RF board may be totally different because the epsilon of the >> > material determine the route impedance for the same substrate >> > material, industrial standard FR4). With a magnifier you can easily >> > make difference between 6 or 10 layers standard board. 10 layers have >> > bigger thickness than 6 layers. Between 2 and 4 layers could be no >> > difference in thikness but is viewable on cross section even without >> > magnifier. >> >> Yes and No... >> >> You can order PCBs in a big range of thickness - if you really want. >> From very thin (below 0.5mm, 20mil) to very thick (beyond 3.2mm, >> 125mil). The normally seen 1.6mm is just a standard thickness (at least >> in europe). The thickness is usually not a direct result of the layer >> number. >> >> A multilayer PCB consists of several base material sheets and prepregs. >> By varying the number and thickness of these a large range of layers is >> possible in a large range of PCB thickness. AFAIK a 10 layer board in >> standard thickness should no problem at all. > > Let's count 6mil between two layers, 10 layer = 9x6mil = 55 mil (1.4mm) > 1 oz per layer = 10 oz = 0.35mm total 0.9+0.35=1.75mm > > So you may do it at limit with only 0.5oz or with a perfect prepreg > arrangement. > Now, how easy you found 6mil prepreg, or when 0.5 oz is a good choice ? > > I think you was to generous with "no problem at all". > > greetings, > Vasile > -- > http://www.piclist.com PIC/SX FAQ & list archive > View/change your membership options at > http://mailman.mit.edu/mailman/listinfo/piclist -- http://www.piclist.com PIC/SX FAQ & list archive View/change your membership options at http://mailman.mit.edu/mailman/listinfo/piclist