PCB - FAQ & Co.

Here you can find several frequently asked questions and answers about our printed circuit boards. You may browse through the categories or use the search. If your question remains unanswered, please contact us by email, phone or contact form. We will reply you as soon as possible.

FAQ:

1. Mechanical Processing
2. Chemical Processing
3. Solder Mask
4. Surface Finish
5. Silk Print
6. Base Materials
7. RoHS/WEEE
8. E-Test
9. Panel Production
10. Tolerances
    1. Why is it necessary to maintain a clearance between copper areas and the routing outline?

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    2. Why is a miminum clearance needed with solder mask bridges?

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    3. Why is the solder mask required to be larger than the appropriate pads?

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    4. How do plot tolerances in films occur?

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    5. Why is the drill pad size in the inner layers required to be larger than in the outer layers?

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       During the pressing process of PCB’s, minor offsets within the various layers may occur. Thus it is necessary to increase the pads’ extensions in the inner layers. The optimum is considered to be 0.5 mm (outer layers: 0.3 mm) plus the final drilling diameter.

       Smaller pads in the inner layers are producible, however the drilled pads may turn out to form a so called sickle within a layer, the drilling not being centrical to the pad that is. Though electrically irrelevant, the sickle-shaped pad is an undesired feature and thus avoided by correct pad sizes.

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    6. Why is the clearance of drillings in the inner layers required to be larger than on the outside?

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Additional information about Printed Circuit Boards (PCBs):

• wikipedia.org
  Online Encyclopedia - Topic PCBs
• www.vde.com
  VDE - Verband Elektrotechnik Elektronik Informationstechnik e.V.
• www.vdi.de
  VDI - Verein deutscher Ingenieure
• www.vdlev.org
  VDL - Verband der Leiterplattenindustrie
• www.zvei.de
  ZVEI - Zentralverband Elektrotechnik- und Elektronikindustrie e.V.
• www.leuze-verlag.de
  Leuze Verlag - Literature about PCBs and PCB production
• www.elektronikpraxis.vogel.de
  Elektronik Praxis - Magazine covering electronics in general and news in the PCB production industry.
• www.elektor.de
  Elektor - Electronics Magazine with manuals and layouts for home made PCBs and PCBAs
• www.ibfriedrich.com (Target 3001)
  The Engineering office Friedrich has been developing layout and CAD software for PCB design and Application Oriented Special Integrated Circuits (ASICs) since 1989.
• www.cadsoft.de
  CadSoft offers user-friendly, powerful, and inexpensive solutions for PCB designs including circuit diagrams, layouts, and autorouting routines.
• http://news.google.de/news
  Worldwide news about Printed Circuit Boards (PCBs)