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WORKSHOP ON PRINTED CIRCUIT BOARD (PCB):

CAD DESIGNING AND FABRICATION BASIC

Prepared and Presented by:

Engr. Mahmudur Rahman Rana Engr. Nasim Ahmed KhanDirector Director Adroit Engineer’s Adroit Engineer’s

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PRINTED CIRCUIT BOARD (PCB)

A printed circuit board (PCB): Mechanically supports and electrically connects electronic components using conductive tracks, pads and other features etched from copper sheets laminated onto a non-conductive substrate.It can be: (1) Single Layer

(2) Double layer (3) Multi layer

PCB + Electronic component = Printed Circuit Assembly (PCA)

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AUTO-ROUTING

Routing: is a step in the design of printed circuit boards (PCBs) and integrated circuits (ICs).

Auto- Routing: is an automated design where the components are routed automatically

after placing the components .

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IS IS AND ARES (AUTO RO UTING)

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BASIC RULES OF PCB DESIGNKeep Tracks as short as possibleTracks should only have angles of 45 degrees. “Snake” your tracks around the board,

Always take your track to the center of the padUse a single track, not multiple tracks

Make sure your tracks go right through the exact center of pads and componentsmake your power tracks as BIG as possible.Keep things symmetricalDon’t leave any unconnected copper fills

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MANUAL vs AUTO ROUTING

Manual Routing Design Auto Routing

Most Difficult Placing the components from schematic

Most Complex Easy to design

Professional Manually mitrer right angle corners

Reliable Unreliable

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MANUALLY PCB DESIGN

For PCB : “You must have……”

SoftwareSimulation of designDatasheets of component usedClear Concept about the Circuit

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TO DESIGN A PCBCopper Board:

(1) Component Side(2) Layer/ Copper Side

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DESIGN PARAMETERSTracksDrills

(1) Drill Hole(2) Drill Solder mark

Green Coating and Heat Coating

Component Package

Clearance

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TRACK

According to IPC-2221 Formula 1A ; 0.03mm thickness, 0.35 mm trace width , 0.0427 ohm,

Vdrop 0.0427 V

1 th (thou/mil) = 0.001 inch = 0.0254 mm

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CLEARANCE

IPC 2221B

Voltage Spacing

1 to 30 V 0.1 mm

31 to 150 V 0.6 mm

151 to 300 V 1.25 mm

301 to 500 V 2.50 mm

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FABRICATION

Fabrication: is the action or process of manufacturing or inventing something.

(1) Hand made/ Home made(2) Industrial

(i) Small Factory (Manually)(ii) Large Industry (Automation)

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HAND OR HOME MADE

Components:(i) Copper Clad(ii)Iron(iii)Inkjet Paper(iv)Hand Drill(v)Ferric Chloride

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SMALL FACTORY

Screen Print(1)Mash frame

(2)Photo-effective

(3)Ferric Chloride

(4)UV Exposer

(5)Print on a copper Clad

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ANY QUESTIONS!!

BEST WISHES TO ALL

THANKS TO EVERYONE