PCB designing Layout and Assembly Process

What is PCB?

Whenever someone is talking about an interesting electronics gadget in front of you, the first thing that came into your mind will be, how this thing is working so efficiently. Answer to that is a printed circuit board which is holding all the required electronics components for a device to work properly. Now what is a PCB also referred as Printed Circuit board. PCB designing is the other part of the game first we need to understand “What is a PCB”?. then “what is PCB designing”? and then we can go for “PCB assembly process”.

There are many terms related to PCB which are commonly used as Printed wiring board (PWB), Etched wiring board. A printed circuit board loaded with electronic components is also called as PCA (printed circuit assembly) or PCBA (printed circuit board assembly).
Printed Circuit board is a copper based rigid board used to draw electronic circuitry on it according to the
required working of the electronics device. The paths which join the electronics components are also
referred to as Traces. There are certain layers of electronics components on PCB which depends on the
complexity or electronics gadget size. Top and bottom layers are used for components placement and
soldering. The multiple layered PCB is often stacked together to reduce the Size of PCB design because
this will allow the components to be placed as near to each other as possible. Multiple layers design is only possible on multiple copper layers of PCB. In multi layered PCB substrate is placed in between each layer. Glass epoxy and cotton paper are commonly used as substrate. Fiber based PCB is shown below in raw form.

Is it boring? Let’s make it interesting with some facts. Do you know when and who invented PCB?
PCB was invented by an Austrian in 1936 whose name was Paul Eisler. He invented PCB when he was
working on a radio set circuit design.

The core material of circuit board is often a poor conductor so that nothing passes between multi layers of PCB unless allowed to pass using Vias. Vias are the joints to connect the two layers of PCB. Normally, Fiber based materials are used as a dielectric.

Applications of PCB Designing

Applications of the printed circuit boards starts from a simple remote-controlled toy and moves on to specially designed military equipment’s.

one of the main applications of PCB is in wireless communication in which antennas are designed using PCB often pronounced as patch Antenna, Slot antenna etc.
Printed Circuit boards are also designed on the basis of their application whether they are being used in
Power application or a bendable structure, so material is selected on the basis of sensitiveness of the
application. In given picture we can see the applications of PCB in real life devices that are normally used
by any user.

PCB designing Applications
Applications of PCB

One more Question, are you curious why majority of PCB are green in color??
Basically, a solder mask is used in PCB hardware preparation so that they can work for a longer period of
time and also the traces are protected from moisture by using mask. Normally mask color is green that’s
why majority PCB look green in color. Also, green color helps in easier fault tracing. Turnkey PCB
assembly offers multiple colors of PCB manufacturing.

PCB Designing

Now, After understanding the Printed circuit board, we can go for the second step to design a PCB that can run specific application. One must simulate a circuit before designing so that it can be verified before
implementing the design on hardware. For that Purpose, different software’s are available on the internet
like Spice, Proteus. Built in libraries are available on these software’s for simulating circuits and if any
component is missing one can design that library according to his needs.

Proteus simulation of Temperature Sensor

PCB designing of a circuit mainly consists of two parts. One of them is schematic design, in which
electronic components are joined with each other according to the required circuit. Second Part is the PCB layout in which the components are placed as we want to see them in physical board so without completing first part one cannot go directly for physical PCB design implementation. After completing the schematic design, connections in layout screen automatically appears (called as nets) and then we have two choices either to choose auto routing option or one can go for manual Routing.

Do you know about CAD, Studied somewhere??
CAD refers to Computer Aided Design that helps design engineers in simulating a circuit before
implementing on hardware.

We can discuss more thoroughly on PCB designing to understand designing completely. To design any circuit, it is mandatory to search out for all the electrical components libraries that are being used in required circuit. Now we can place the components one by one in organized manner so that it is easy to connect them with each other using connectivity lines. These connectivity lines are often called as nets.
After completing the circuit on CAD software, try to simulate the circuit and verify the required output
before going for proper schematic and PCB layout design. Antenna designing Software’s are Normally
different than other PCB designing Software’s.

Do you ever wonder about the thin lines on any PCB circuit??
These thin lines are called Traces and they can be called as wires in simple words.

Verified circuit can be then designed on layout by selecting proper design constraints. We can select
distance between the two components, distance between two traces and many more settings. There are two types of components available in layout design library those are called as surface mount components and through hole components. Surface mount components do need holes in PCB, they are soldered on top of PCB while through hole components needs drilling in PCB.
Most of the advanced devices use SMD components which are of minimal sizes thus saving the space on
PCB that will help in compact PCB designs. As a beginner one should place through hole components
because they are easy to be placed and soldered at their position on PCB. After placing Components on
PCB proper width of traces is selected according to the current/Voltages passing through them. Auto router option in designing software will save the headache of manual routing. Just choose your desired settings and go for auto routing, one can adjust routing after auto routing is done by software.

You may have seen C1, R1, U1 Written on Top side of PCB, do you know about them??
Those are components Markings that should be placed on exactly same place otherwise the PCB will not
work. They are Embed on PCB using Silk screens or using an inkjet Printer.

It should be kept in mind that power planes of the design should be according to the circuit application for-example if it is used in power supply or power inverter then power planes should be of more width but for application like a remote control of toy car do need too much power so it can use normal copper traces for power transfer.
Now we are almost done with the PCB designing, just recheck your design if you can find any mistakes.
The final stage of designing will include some markings on top of the PCB that will help in components
placement, troubleshooting and for brand name or copyright information. You can create a final bill of
materials from the software to guess the estimated price of components that are being used in design.
Multi-layer PCB designs are more complex than a single or dual layer designs. After designing of multi
layers all of the layers are submerged with each other to make a single PCB in hardware. For that purpose,
output files are generated to be sent for fabrication process.

Multi-Layer PCB design

Do you know about Turnkey PCB assembly?
Turnkey PCB assembly is a term often used for PCB manufacturing which solves all the PCB
manufacturing problems. Turnkey PCB assembly will offer a complete fabrication of your printed circuit
board design including components placement and soldering.

PCB fabrication

Printed circuit board Fabrication will include a starting stage of printing layout on PCB, then etching which
will remove the extra copper from the PCB. Components are placed according to the PCB layout by
assembly facility and a soldering process is done to solder all components properly on PCB. Final stage of
the PCB manufacturing includes the testing and troubleshooting of design. If there are no faulty pieces in
the final PCB assembled, then it will be delivered to the customer.it would be a better idea to use turnkey
PCB assembly for hardware development of a PCB design.

To design an efficient PCB, the assembly and manufacturing plant needed should be of high precision.
Hence one should select a proper PCB manufacturing company after designing the printed circuit board.
There are number of companies offering Turnkey PCB assembly and manufacturing solutions that can be
really helpful for a certain user who don’t know too much about PCB assembly and manufacturing process. Hence all of these topics PCB designing,Layout and PCB assembly are interlinked.