PCB Design

What Is PCB ?
A PCB is a printed circuit board, also known as a printed wiring board. It

is used in electronics to build electronic devices. A PCB serves two purposes in
the construction of an electronic device; it is a place to mount the components and
it provides the means of electrical connection between the components.
COMPONENTS OF PCB
TYPES OF PCB
FABRICATION
Following are the basic steps of PCB design.
• Set-Up
• Imaging
• Etching
• Drilling
• Masking
• Silk Screening
• Route
• Electrical Test
PCB Design Tools
• Schematic Capture
• Component Footprint Editor
• PCB Layout
• PCB Auto router
• Analog/Digital Simulator
• Signal Integrity Analysis Tools
• vendor :
– Orcad
– Allegro
– Eagle
– P-CAD
The Control Panel
First Look At Eagle

Create Library Components
Drawing The Schematic
Create The Board
Place The Parts
• Component placement is an
extremely important function of the
designer.
• Components should be placed
according to their connections to other
components, thermal considerations,
mechanical requirements, as well as
signal integrity and rout ability.
•Components which have connections
to each other should be placed in the
same vicinity.
•For example, a processor should be
placed very close to the RAM and
Flash ICs on which it relies.
•Components should also be placed on
a grid, usually a 100 mil grid, in order
to provide for a symmetric flow of
routing where tracks and components
are lined up.
Route The Signals
Edit The Board
Auto-Route The Board
•CAD tools provide auto-router
and board wizard functionality.
•In reality, PCB designers
don’t use an auto-router.
•The technology behind an auto-
router has a science of its own,
drawing from disciplines such as
artificial intelligence, heuristic
algorithms, and ultimately
attempting to solve the traveling
salesman problem.
•The irony is, only a very
experienced PCB designer can
take advantage of an auto-router,
and even then, it is only used for a
fraction of the board.
Copper Pouring
Check The Board (DRC)
•The Design Rule
Check (DRC) checks
the board you designed
against a set of rules to
determine if you made
any errors.
•The Design Rules of
a board can be
modified through the
Design Rules dialog,
which appears if the
DRC command
selected is
terminating. without
a
Produce Manufacturing Data
Manufacturing Guidelines
• Internal layers should be designed at least 15” away from the

edge of the PCB board. This is to ensure that the manufacturer
of the board does not cut into the copper or short the planes.
You can employ the keep out layer for this purpose.
• Each manufacturing house has their own manufacturing
guidelines for minimum space width, copper-to-edge distance,
via and hole sizes, annular ring, etc.
•Many assembly houses require that you provide your PCB
boards in a panelized format. Panelizing a design means fitting
multiple boards on a standard panel. Once the assembly is
done, they are cut into individual PCB boards.
Film Generation
• The film is generated from the design files. which are sent to the
manufacturing house. One film is generated per layer.
Shear Raw Material
Industry standard 0.059” thick, copper clad panel.
Drill Holes
Using NC machines and carbide drills to drill holes according to the
drill spec sent to the manufacturing house.
LPKF ProtoMat S100
PCB Plotter (Milling & Drilling)
LPKF Drilling And Drilling Head Drilling And

Milling Machine Milling Tool
PCB Electroplating
• Apply copper in hole barrels.
Apply Image
• Apply Photosensitive Material to develop selected areas from
panel.
Strip and Etch
• Remove dry film, then etch exposed copper.

• Tin protects the copper circuitry from being etched.
Solder Mask
• Apply solder mask area to entire board with the exception of
solder pads.
LPKF (Laser & Electronics)
(U-V Exposure)
•The PCB is placed in

the image exposure unit
and the artwork is
placed over it using
registration marks.
•The exposure unit is
switched on for 30
seconds after which the
board is removed and
the artwork film pulled
off.
Solder Coat
• Apply solder to pads.
Silkscreen
Apply white letter marking using screen printing
process.
Silkscreen Layer
• The silkscreen layer is also known as Overlay. Top Overlay refers
to the silkscreen on top of the board, and Bottom Overlay refers to
silkscreen on bottom
• This is the layer onto which the component designators are printed
(R1, R2, …) so as to identify individual components during
component placement of the board
• They are also used during the PCB routing process to indicate the
outlines of your components. This helps you in placing (or not
placing) components too close to one another, or too close to the
edge of the board.
• Make sure your silkscreen doesn’t run over any exposed copper
(such as pads)! pulverized
• video
Measures of Recycling Performance
1. Capture rate
2. Participation rate
3. Recycling rate
4. Diversion rate
1. Capture rate
• The term capture rate (also referred to as the source
recovery factor) denotes the weight percent of an
eligible material in the total e-waste actually separated
out for recycling.
• Capture rate applies to a single material, not recyclables

in general.
2. Participation rate
• The term participation rate denotes the percent
of E-waste that regularly set out recyclables.
3. Recycling rate
• The term recycling rate is sometimes used to
denote the quantity of recyclables collected per
user/ producer per unit of time.
4. Diversion rate
• Another performance factor in gauging the success
of a recycling program is the diversion rate, which
represents the weight of total e-waste that is not
landfilled.
Facts and Figures
6000
mobile
phones
gives
6
References
• http://www.google.com
• http:// www.wikipedia.org
• http://www.pcbexpress.com

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PCB Design

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What Is PCB ?

A PCB is a printed circuit board, also known as a printed wiring board. It

First Look At Eagle

• Internal layers should be designed at least 15” away from the

LPKF Drilling And Drilling Head Drilling And

• Remove dry film, then etch exposed copper.

•The PCB is placed in

• Capture rate applies to a single material, not recyclables

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