Hi Vasile: I don't know if you will understand this transliteration (probably a clumsy one) but it will be interesting to see. I tell my kids, "Pavtarenia matra chenia." please do not be offended if it is not a language with which you are familiar. Regards Rich ----- Original Message ----- From: "Vasile Surducan" To: "Microcontroller discussion list - Public." Sent: Monday, June 12, 2006 2:00 AM Subject: Re: [EE:] Visually determining PCB layer count > On 6/12/06, Rich Graziano wrote: >> Vasile: You are a good guy to have on this list. > > No. I'm just old and grumpy. Unfortunately "old" means a little experience > and nothing more. There is a true word here, with an approximate > translation: "Experience is what is making life with man and not what > is doing man with his life" > However, thank you for your too kind remark. > > greetings, > Vasile > >> 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 >> > -- > 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