PCB Designing Process

8/3/2019 PCB Designing Process

1/17

Getting Familiar


2/17

PCB stands for printed circuit board which are used for wiring

up of the component of circuit .

Single side PCB have copper foil on one side while the double

sided PCB have a copper foil on both side of laminate Thickness of copper foil is 35 micrometer minimum on cheaper

PCB and 70 micrometer on a costly PCB

Tracks are made by masking the track part of copper with each

resist enamel paint and later dipping the laminate in ferric

chloride solution to dissolve all the copper except under the

mask part


3/17

The most important task in making any project is to

design its PCB. PCB is an abbreviation of Printed

circuit board. Printed circuit board is a copper clad

board on which tracks are designed through which thecurrent flows according to the circuit diagram.


4/17

Take a copper clad board of appropriate size according to the

circuit layout.

Draw the PCB layout on the transparency sheet with the help ofpermanent marker.

Take a photo film of appropriate sizes according to the PCB

layout

Put the photo film and transparency sheet in the proto contactmachine.


5/17

After one or two minutes take out the photo film from themachine and rinse into the solution of Ammonium

sulphate until we see a complete layout.

After that wash the photo film in water and Ag fix

solution and finally negative is prepared.

Now put the copper clad board into the Dip coat

machine for two three times for coating a smooth layer

of gum.


6/17


7/17


8/17

After that put the copper clad board into the dryermachine for 5 to 7 minutes.

Suitably placed the copper clad board and

negative in the Ultraviolet Exposure machine for two

minutes.

After that put the copper clad board into the

Developer machine for 5 to 7 minutes.

Now put the copper clad board into the dye

machine, so that the PCB layout is printed on the

copper clad board and dry it.


9/17


10/17

Design the tracks with the help of a permanent marker

on the copper clad board.

After finishing track designing once, do at least 3

coats of permanent marker on the copper glad boardto make the tracks darker so that the copper beneath

the permanent marker coating may not be removed

during the etching process which is explained in the

next point


11/17

Now our PCB is ready to be etched. In this step we pour our

PCB in an etching solution. Etching solution is nothing but achemical solution of Ferrous Chloride (FeCl3). This solution

reacts with the copper of copper glad board and except the

copper beneath the permanent marker coating. Rest of the

copper is washed away from the copper glad board. This

process takes 5 minutes approximately.

Wash the PCB with clean water and dry it.

Once the whole PCB is etched, the permanent marker coating

has to be removed from the board. For this the PCB is rubbedby an iron scrubber.


12/17


13/17


14/17

This is the time to check the PCB for short circuit between the

tracks. For this purpose, we use a digital multimeter.Continuity is checked between all the tracks where there is a

possibility of short circuiting.

Now the time is to mount the components into the PCB. But for

this we have to make holes where we want to mount our

components. The holes are to be drilled with the help of a

drilling machine using a 1mm drill bit. The holes have to be

drilled exactly at the place as shown in the PCB layout.

Mount the components into the PCB and solder them with the

help of a fine tip solder iron. Soldering should be done verycarefully there are chances of short circuits in between

adjacent tracks. Now the PCB is ready to use in our project.


15/17


16/17

1.Negative development through Proto Contact Machine: In

this machine the negative exposure is done. After this, the

negative is passed through 2 types of solution. First one is

ammonium sulphate solution and second one is fixer solutioni.e. Ag fixer solution.

2.Dip Coat Machine: This machine conatins a solution of

photoresist material of E1020 type.

3.Photocure: this woks as a drier.A

fter dip coatingPCB

isdried in this machine.

4.Ultraviolet Exposure machine: In this machine the negative

made is printed on PCB.


17/17

5.Developer and Dye Machine: After UV exposure PCB is

placed in developer machine which contains developer

solution. After that PCB is put in Dye machine which fixes thelayout on PCB.

6.Etcher Machine: This machine contains FeCl3 solution which

removes all the extra copper on PCB.

7.Drilling Machine: The drilling is done on the drilling machine.

PCB Designing Process

Documents

Transcript of PCB Designing Process