Basic terms questions about PCB design

1.what's difference between negative plane and positive plane?
2.what's mean plated,should the normal pad be plated?
3.what' usage of the characters,when design padstack,drill/slot ,symbol.
4.what's mean soldermask?
5.wha t's mean pastemask?
6.what's difference between assemble outline and silkscreen outline?
thank you.

Re: question on allegro?

These are not questions on Allegro rather on PCB design!!

Regards,

Majnoon

question on allegro?

1. A negative plane is a plane that has uses "positive" data to represent non-copper. The gerber file is then inverted by the service buro that prepares the photo plots. Thus, such a plane data will be less bytes that a positive one.

2. A plated through hole has copper in it. This enables a copper connection from the top to the bottom side. You can not make multi layer PCB's without plated holes. A via hole is always plated. If your design is very simple it may not need double sided boards and thus no through hole plating.

3. The service buro sometimes needs this. At least where I live in scandinavia this is no longer rerquired. The drill files and their descriptions is normally good enough.

4. Solder mask = green lacquer on the PCB that should prevent solder from escaping from the solder pads in the soldering process. The mask also acts as insulator.

5. The paste mask is a separate layer not used in the PCB. Instead, this layer goes to the assembly plant that produces a metal stencil placed upon the pcb and then used for smearing solder paste onto the naked board.

6. The Assembly outline is used in (paper) drawings to show detailed information about pinning, orientation, dimensions and such. This layer is never printed on the board. The silk screen layer is the (text) layer that normally gets printed on the board. It contains reference designators, pin numbers, warning texts such as "High Voltage" and board part number.

Re: question on allegro?

your explination very wonderful.
i get it.thank you very much.

Re: question on allegro?

Really useful.....

Re: question on allegro?

Before you even use a CAD system for PCB design you should at least learn some of the basics. I would suggest you learn how PCB's are manufactured and assembled. As a bare minimum the following links would be a good place to start.
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http://www.ucamco.com/public/RS-274X_Extended_Gerber_Format_Specification_201012.pdf
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http://pcbtalk.com/data/upload/Designing_Balanced_PCBs.pdf
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http://www.alternatezone.com/electronics/files/PCBDesignTutorialRevA.pdf
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http://www.ece.unh.edu/courses/ece7...onent Zero Orientations for CAD Libraries.pdf
http://www.smtnet.com/library/files/upload/The-Universal-PCB-Design-Grid-System.pdf
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http://www.analog.com/static/imported-files/tutorials/MT-008.pdf
Right the First Time