VISVESVARAYA TECHNOLOGICAL UNIVERSITY

BELAGAVI, KARNATAKA-590018

INTERNSHIP REPORT
ON
“PCB Assembling & Designing using SMT Technology & Proteus”

BACHELOR OF ENGINEERING
in
ELECTRONICS AND COMMUNICATION ENGINEERING

Submitted by
PRAJWAL M P [4MG21EC025]
Under the Guidance of
Mr. Hemanth Kumar M S
Assistant Professor,
Dept. of Electronics & Communication Engineering

DEPARTMENT OF ELECTRONICS AND COMMUNICATION ENGINEERING

G. MADEGOWDA INSTITUTE OF TECHNOLOGY

(AFFILIATED TO VTU, APPROVED BY AICTE, NEW DELHI & GOVT.OF KARNATAKA)
BHARATHINAGARA, MANDYA, KARNATAKA-571422
2023-2024
 G MADEGOWDA INSTITUTE OF TECHNOLOGY
BHARATHINAGARA, MANDYA, KARNATAKA-571422

DEPARTMENT OF ELECTRONICS AND COMMUNICATION ENGINEERING

2023-24

CERTIFICATE

This is to certify that the Internship titled “PCB Assembling & Designing using
SMT & Proteus” is a Bonafede work carried out by PRAJWAL M P
(4MG21EC025) in the partial fulfillment for the award of Bachelor of Engineering in
ELECTRONICS A N D COMMUNICATION ENGINEERING of Visvesvaraya
Technological University, Belagavi, during the year 2022-23. The report has been
approved by the academic requirements, prescribed for the award of Bachelor of
Engineering Degree.

Signature of Guide Signature of HOD Signature of Principal

(Mr. Hemanth Kumar M S) (Dr. Nuthan A C) (Dr. Chandan B R)

Assistant Professor, ECE, GMIT Head of Dept. ECE, GMIT Principal of GMIT

Name of the Examiners Signature of the Examiners

1.

2.
 ACKNOWLEDGEMENT

Any Project work completed successfully gives a great sense of achievement and
satisfaction. It would remain incomplete if the people who made it possible and whose constant
guidance and encouragement to without mention.

First and foremost, First and foremost, I would like to express my sincere gratitude to our
beloved Principal, Dr. CHANDAN B R for providing us a congenial environment for
engineering studies and constant support.

We express our heart filled thanks to, Dr. NUTHAN A C, Professor and Head of the
Department of Electronics and Communication Engineering GMIT, Bharathinagara, Mandya,
whose guidance and support goes beyond works.

We express my earnest gratitude towards my coordinator Mr. Hemanth Kumar M S

Assistant Professor, Department of Electronics and Communications Engineering, who
helped me in getting things done and was always inspirational.

We would like to thank our Guide NAMRATHA M P, Technical Trainer, Tycoon

Innovative Technology, Mysore for his support, guidance, motivation, encouragement for the
successful completion of this project.

We gratefully acknowledge the help & cooperation offered by all the teaching and non-
teaching staff members of Department of Electronics and Communication, GMIT,
Bharathinagara, Mandya.

Above all, we would like to thank our parents and friends for their cooperation and God,
the Almighty, for his blessings and strength.

PRAJWAL M P
[4MG21EC025]
 STRACT

Overview of PCB design and assembly with a focus on Surface Mount

Technology (SMT). Importance of miniaturization and performance in modern
electronic devices. Explanation of SMT technology and its advantages over
traditional through-hole assembly. Emphasis on compact design and increased
component density. Integration of Proteus software for PCB layout simulation and
testing. Significance of virtual prototyping in reducing errors and optimizing
designs. Real-world application scenarios showcasing the successful
implementation of SMT technology and Proteus in PCB design and assembly.
Conclusion highlighting the relevance and impact of the research in advancing
electronic manufacturing processes.
 CONTENTS

SL.NO HEADING’S

1. About company

2. IPC

3. PCB (Printed Circuit Board)

4. ESD (Electrostatic Discharge)

5. Hardware and Software requirements

6. Stores

7. SMT (Surface mounting technique or device)

8. Through hole assembly

9. Cleaning

10. Quality control

11. Final quality check

12. Packing

13. Advantages and Applications

14. Hand’s-on experience

Conclusion
15.
 List of Figures

SL.NO HEADING’S

1. Flow Chart EMS

2. SMT Flow Process

3. Automatic Screen printing

4. Pick and place machine

5. Pick and place process

6. Reflow waveform

7. Reflow machine

8. Through-hole resistors

9. Through-hole electrolytic capacitors

10. Manual through-hole mounting

11. Wave soldering machine

12. Skeleton of wave soldering

13. Hand soldering

14. Hand soldering process

15. Dip soldering process

 PCB Assembling & Designing using SMT Technology & Proteus.

CHAPTER 1
INTRODUCTION
1.1 Company profile

Tycoon Innovative Technology

Hebbal, Mysuru, Karnataka

Tycoon innovative technology has state of art infrastructure and technology equipment to create
and deliver sustainable business value to customers seeking to outsource design, development or
manufacturing of their products. we are a professional & dependable electronics manufacturing
services company engaged in contract manufacturing of PCB assembly with through hole, SMD,
ROHS, non ROHS, metal core PCB & led assemblies, BGA assembly etc. Located in the Mysore city
of India.

Tycoon innovative technology is established in the year 2014 in Mysore, delivers total
manufacturing solutions very best of the electronics manufacturing process and Business practices
with integrated business verticals to cover the entire bandwidth of electronics manufacturing services
starting from design services to prototyping, sourcing, turnkey manufacturing, and support services.
We specialize in quick-turn services for highly complex and advanced PCB assembly and systems
manufacturing meeting dynamic business needs and competent engineering and manufacturing team
to help many customers to give complete solutions all kind of PCB assembly requirements.

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1.2 IPC (Association Connecting Electronics Industries)

IPC, the Association Connecting Electronics Industries, is a trade association whose aim is
to standardize the assembly and production requirements of electronic equipment and assemblies. It
was founded in 1957 as the Institute for Printed Circuits. Its name was later changed to the Institute for
Interconnecting and Packaging Electronic Circuits to highlight the expansion from bare boards to
packaging and electronic assemblies. In 1999, the organization formally changed its name to IPC with
the accompanying tagline, Association Connecting Electronics Industries.

Chairman of IPC is Joe O’Neil and President & CEO of IPC is John W. Mitchel

IPC is accredited by the American National Standards Institute (ANSI) as a standards developing
organization and is known globally for its standards. It publishes the most widely used acceptability
standards in the electronics industry.

IPC is headquartered in Bannockburn, Illinois, United States and maintains additional offices in
Washington, D.C.; Taos, New Mexico; Arlington County, Virginia, in the United States; Stockholm,
Sweden; Brussels, Belgium; Moscow, Russia; Bangalore, India; and Shanghai, Shenzhen and Beijing,
China.

IPC standards are used by the electronics manufacturing industry. IPC-A-610, Acceptability of
Electronic Assemblies, is used worldwide by original equipment manufacturers and EMS companies.
There are more than 3600 trainers worldwide who are certified to train and test on the standard.
Standards are created by committees of industry volunteers. Task groups have been formed in China,
the United States, and Denmark.

General document
➢ IPC-A-600 Acceptability of Printed Boards
➢ IPC-A-610 Acceptability of Electronic Assemblies
➢ IPC-I-STD-002 Soldering Acceptance

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1.3 PCB (Printed Circuit Board)

1.3.1 Classifications of PCB
Class-1: “General Electronics Products”, it includes products suitable for application where the
major requirement is function of completed assembly. Example: Kids Toys, Electronics etc.

Class-2: “Dedicated Service Electronics Products”, it includes products where continued

performance and extended life is required and for which uninterrupted service is desired but not
critical. Typically, the end use environment would not cause failure.
Example: Mobile, Laptop, Radio, Television etc.

Class-3: “High Performance Electronics Products”, it includes products which continued

performance on critical demand. Equipment down time cannot be tolerated and using environment may
not be common and equipment must function properly when it is required in such situations like life
support or critical system.
Example: Aerospace, Defence, Military, Medical equipment etc.

1.4 ESD (Electrostatic Discharge)

Electrostatic discharge (ESD) is the sudden flow of electricity between two electrically
charged objects caused by contact, an electrical short, or dielectric breakdown. A buildup of static
electricity can be caused by electrostatic induction. The ESD occurs when differently-charged objects
are brought close together or when the dielectric between them breaks down, often creating a visible
spark.

ESD can create spectacular electric sparks (lightning, with the accompanying sound of thunder, is a
large-scale ESD event), but also less dramatic forms which may be neither seen nor heard, yet still be
large enough to cause damage to sensitive electronic devices. Electric sparks require a field strength
above approximately 40 kV/cm in air, as notably occurs in lightning strikes.

ESD can cause harmful effects of importance in industry, including explosions in gas, fuel vapor and
coal dust, as well as failure of solid state electronics components such as integrated circuits. These can
suffer permanent damage when subjected to high voltages. Electronics manufacturers therefore
establish electrostatic protective areas free of static, using measures to prevent charging, such as

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avoiding highly charging materials and measures to remove static such as grounding human workers,
providing antistatic devices, and controlling humidity.

1.4.1 Causes of ESD

One of the causes of ESD events is static electricity. Static electricity is often generated through
turbocharging, the separation of electric charges that occurs when two materials are brought into contact
and then separated. Examples of turbocharging include walking on a rug, rubbing a plastic comb against
dry hair, rubbing a balloon against a sweater, ascending from a fabric car seat, or removing some types
of plastic packaging. In all these cases, the breaking of contact between two materials results in
turbocharging, thus creating a difference of electrical potential that can lead to an ESD event.

Another cause of ESD damage is through electrostatic induction. This occurs when an electrically
charged object is placed near a conductive object isolated from the ground. The presence of the charged
object creates an electrostatic field that causes electrical charges on the surface of the other object to
redistribute. Even though the net electrostatic charge of the object has not changed, it now has regions
of excess positive and negative charges. An ESD event may occur when the object comes into contact
with a conductive path.

1.4.2 Types of ESD damages

1. Catastrophic failure: Catastrophic failure causes a failure in an ESD sensitive item that is
permanent. The ESD event may have caused a metal melt, junction breakdown or oxide.
failure. Normal inspection can detect a catastrophic failure. A latent defect can occur when an
ESD sensitive item is exposed to an ESD event and is partially degraded. It may continue to perform
its intended function, so may not be detected by normal inspection. However, intermittent, or permanent
failures may occur later.
2. Latent failure: A device that is exposed to an ESD event may be partially degraded, yet.
continue to perform its intended function. However, the operating life of the device may be reduced
dramatically. A product or system incorporating devices with latent defects may experience a premature
failure after the user places them in service.

Latent damage caused by ESD is potentially more costly since damage occurs that cannot be felt, seen,
or detected through normal inspection procedures. Latent defects can be very expensive as the product
passes all inspection steps, and the product is completed and shipped. Latent defects can severely impact
the reputation of a company’s product. Intermittent failures after shipping a product can be frustrating,
particularly when the customer returns a product, reporting a problem which the factory again fails to

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detect. It consequently passes inspection, and the product is returned to the customer with the problem
unresolved.
1.4.3 ESD protection devices

ESD Apron ESD

Slippers ESD Shoe

Wrist strap and ESD Mats

1.5 5’S

1. Sort (seiri): The first pillar of the visual workplace which focuses on eliminating and removing
all unnecessary items from the workplace that are not needed for current production operations.
Sorting the items is according to three categories such as useful, useless, and unknown. The
useless items are disposed immediately because they just jamming the workplace led to loss of
time. For items unknown, the frequency of using them not clear, they can be kept with
monitoring to decide by red tag strategy. Through the suitable sorting it can be identified the
materials, tools, equipment, and necessary information for realization the tasks.
2 Set in order (Seitan): According to Chapman (2005), set in order process can be defined as
essential material and items are organized to minimize wasted employee motion, walking and
material movement. Besides that, set in order focuses on creating efficient and effective storage
methods to arrange the items and parts, so that they are easy to use. Forming a regular
workplace, avoiding time loss while searching for material and so improving the efficiency are
the main objectives.
3 Shine (Seiso): Once the clutter at work areas is eliminated and remaining items and parts are
organized nicely; the next step is to thoroughly clean the work area. It is the component that
emphasizes the removal of dirt, grime, and dust from the workplace. Cleaning should become a
daily activity. Workplace should be cleaned at regular intervals.
4 Standardize (Seiketsu): It refers to the practice of standardizing in the working area by
developing methods to maintain the achievements of the first three. The workers need to ensure
their effort to tidy, organize, clean the work area and newfound disciplines are not slowly lost.
Hirano (1995) defined standardize as a result that exists when the first three pillars are properly
maintained. To establish standards of the best practice in the workplace and to ensure that the
standards are compiled and to undertaking that the workplace is always clean and tidy.

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5 Sustain (Shitsuke): The last step of 5S program is covering the improvement of the methods
directed to the adaptation of 5S activities as habits by all personnel. Hirano (1995) stated that
sustain can be define as to make habit of properly maintaining with the correct procedures.
According to Mcbride (2003), the last pillar is requiring discipline. Without discipline, it is
impossible to maintain consistent standards of quality, clean production, and safety and process
operations at the workplace. The task here is undertaken by the leader directors. The directors
should explain the importance of 5S to the personnel through various trainings and the
knowledge of the personnel about 5S should be kept updated through the 5S boards to be formed
at the workplace.

6 Hardware and software requirements

Sl. No Hardware and Software used Description

1 Pick and Place machine It is used to pick and place the component into a
teaching location.
C language is used in this machine for
component assembly.
2 Reflow machine It is used to solder the SMT components.
3 Station It includes solder gun, lead, temperature setting
equipment for hand soldering.
4 Wave soldering machine It is used to solder the through-hole assembled
components.
5 Daisy tool It is a forming device used for component
cutting for a required length.
6 Jig device It is used for the inspection of components and
boards.
7
8 Table.1.6 Hardware and software requirements

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CHAPTER 2
WORKING METHODOLOGY OF ELECTRONICS
MANUFACTURING SERVICES(EMS)
The Fig.2.1 describes the flowchart of electronics manufacturing services, that explains as follows.

2.1 Stores

It is classified into incoming stores and holding stores.

I. Incoming Stores:
Request for Quotation (RFQ): The customer sends the RFQ to the supplier specifying the
quantity of goods required and requesting for the quotation regarding the price details from the
supplier.
Purchase Order (PO): After receiving the RFQ the customer again specifies the required
amount of goods with specifications and sends the PO to the supplier.
Invoice: The goods received contains an invoice describing the price details.
Invert Quality Control (IQC)
Bill of Material (BOM): It provides product specification, manufacturer details, Part number,
list of components and value of the components.
Data Sheet: It is used as a reference for verification of products in IQC and to verify the
dimensions and values.
Inspection is of two types namely:
1. 100% inspection: All components in a lot or batch is inspected.
2. Sampling inspection: Only a sample in a batch of goods is verified.
For Passive Components electrical value is measured using LCR meter and dimensions are
measured using Vernier calliper.
For Active Components only dimensions and top marking are checked as per data sheet.

II. Holding Stores:

ROHS: Restriction of Hazardous substances. These are lead free products and are stored
separately.

Non ROHS: They are leaded products and are stored away from the ROHS products.

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Incoming material

Through hole
store
component forming

SMD assembly

Reflow

Reflow solder.
touch-up

Through hole
assembly

Wave soldering

Post machine.
soldering operation

Lead cutting.

Cleaning

Quality control

Final inspection

Packing and
dispatch

Fig.2.1: Flow Chart EMS

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Shelf-life Monitor: This follows the principle of FIFO. The goods that arrive first are first
supplied to the production unit. The next arriving components are stored separately. These
are differentiated as through hole and SMD (Surface mounting device) components and
through hole components are delivered to through hole assembly process.
Material Request Note (MRN): The production unit sends a MRN to the holding stores
based on which the goods are supplied to them. After supplying the required goods, the
stock detail is updated.
Rejected Materials: Rejected materials are stored separately. It is monitored and reviewed
by the Monthly Review Board (MRB).

2.2 SMT (Surface mounting technique or device)

BAKING SCREEN PICK AND REFLOW

PRINTING PLACE

Fig.2.2: SMT Flow Process

Surface-mount technology (SMT) is a method for producing electronic circuits in which

the components are mounted or placed directly onto the surface of printed circuit boards (PCBs).
An electronic device so made is called a surface-mount device (SMD). In industry, it has largely
replaced the through-hole technology construction method of fitting components with wire leads
into holes in the circuit board. Both technologies can be used on the same board, with the through-
hole technology used for components not suitable for surface mounting such as large transformers
and heat-sinker power semiconductors.

By employing SMT, the production process speeds up, but the risk of defects also increases due to
component miniaturization and to the denser packing of boards. In those conditions, detection of
failures has become critical for any SMT manufacturing process.

An SMT component is usually smaller than its through-hole counterpart because it has either smaller
leads or no leads at all. It may have short pins or leads of various styles, flat contacts, a matrix of
solder balls (BGAs), or terminations on the body of the component.

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2.2.1 Baking
It is the process of removing moisture content from bare PCB. It
follows the baking standard – IPC HDBK 001
The baking standard defines the required time and temperature depending on the PCB
thickness and component package.
The baking standard can also be defined by the customers which is the customer standard.
Recommendations for PCB baking profiles:
Final Finish Temperature Time
Tin 105-125°c 4-6 hours
Silver 105-125°c 4-6 hours
Nickel/Gold 105-125°c 4-6 hours
HASL/HAL 105-125°c 4-6 hours
Table.2.1 IPC-1601
2.2.2 Screen printing
The application of the solder pastes onto the PCB at areas where the components are to be
mounted using stencils which are unique for each type of PCB. Types:

a) Automated
b) Semi-Automated
c) Manual
a) Automated Screening:
The PCB to be mounted is sent into an automated screening machine through conveyor. The
machine is programmed with parameters like PCB dimensions, thickness of paste,
detach sequence etc.
The PCB is screened according to the requirements and is output through the conveyor.

Fig.2.3 Automatic Screen printing

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b) Semi-Automated Screening:
The basic requirements are stencil, squeegee, solder paste etc.
The PCB to be screened is fitted to the stencil and the paste is applied on the machine. The
squeegee moves at an angle 90° to the board and applies paste evenly at areas to be mounted.
c) Manual Screening:
The board is placed below the stencil and paste is applied manually. The
stencil must be frequently cleaned to ensure there are no blocks.

2.2.3 Pick and place

The screened board is fed to the Pick and Place machine which is programmed and
accordingly it picks the components and places.
It consists of a feeder, camera, different size nozzles, placement head etc.
The components of different size are fed through the feeders and the nozzle picks components
and places on the PCB.

Fig.2.4 Pick and place machine

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Fig.2.5 Pick and place process

2.2.4 Reflow
The soldering of the SMD components is done using a reflow machine.
When used on boards containing both SMT and THT components through hole reflow allows
the wave soldering step to be eliminated.
A conventional reflow process has four stages called ‘zones’, each having a distinct thermal
profile.
The zones are: Preheat, thermal soak, reflow and cooling.
Temperature at each zone increases gradually and at the peak temperature actual reflow
occurs.

A profiler is used to detect the actual temperature at each stage.

Fig.2.6 Reflow waveform.

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Fig.2.7 Reflow machine.

2.3 Through hole assembly

Through-hole technology (THT), also spelled "THRU-HOLE", refers to the mounting
scheme used for electronic components that involves the use of leads on the components that are
inserted into holes drilled in printed circuit boards (PCB) and soldered to pads on the opposite side
either by manual assembly (hand placement) or by the use of automated insertion mount machines.

Fig.2.8 Through-hole resistors Fig.2.9 Through-hole electrolytic capacitors

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Fig. 2.10 Manual through-hole mounting

While through-hole mounting provides strong mechanical bonds when compared to SMT techniques,
the additional drilling required makes the boards more expensive to produce. They also limit the
available routing area for signal traces on layers immediately below the top layer on multilayer boards
since the holes must pass through all layers to the opposite side. To that end, through-hole mounting
techniques are now usually reserved for bulkier or heavier components such as electrolytic capacitors
or semiconductors .

Design engineers often prefer the larger through-hole rather than surface mount parts when
prototyping, because they can be easily used with breadboard sockets. However, high - speed or high
frequency designs may require SMT technology to minimize stray inductance and capacitance in wire
leads, which would impair circuit function. Ultra-compact designs may also dictate SMT construction,
even in the prototype phase of design.

Through-Hole Technology involves 3 processes:

1. Masking
2. Stuffing
3. Soldering

2.3.1 Masking: Masking is used to prevent the part from soldering and that part will be covered
with tapes.

2.3.2 Stuffing: Stuffing is the process of placement of components using CAD (Computer Aided
Design).

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There are two types of stuffing:

i. Line assembly – 4 or 5 members divides stage according to components.

ii. Mass assembly – Whole components is mounted by single person.

2.3.3 Soldering: Soldering is a process in which two or more items (usually metal) are joined together
by melting and putting a filler metal (solder) into the joint, the filler metal having a lower
melting point than the adjoining metal.
There are different types of soldering:
a) Wave soldering
b) Hand soldering
c) Dip soldering.

a) Wave soldering:
Wave soldering is a bulk soldering process used in the manufacture of printed circuit.
boards. The circuit board is passed over a pan of molten solder in which a pump produces an upwelling
of solder that looks like a standing wave. As the circuit board contacts this wave, the components
become soldered to the board. Wave soldering is used for both through-hole printed circuit assemblies,
and surface mount. In the latter case, the components are glued onto the surface of a printed circuit
board (PCB) by placement equipment, before being run through the molten solder wave. Wave
soldering is mainly used in soldering of through hole components. The locations which must be
unsoldered is masked or even pallets can be used to cover the locations that have to be free from
soldering.

Fig.2.11 Wave soldering machine

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There are two waves in molten state:

1. Conventional wave
2. Chip wave.
1.Conventional wave: When SMD components are present only on top side of the PCB then
conventional wave is used.
2.Chip wave: When SMD components are present on both sides chip wave is used.

Fig.2.12 Skeleton of wave soldering

The sequence of wave soldering is.

Assembling the components on PCB, passing it with the help of conveyor

Applying flux
Preheating
Molten lead bath
cooling

The basic equipment used during the process is a conveyor that moves the PCB through the
different zones, a pan of solder used in the soldering process, a pump that produces the actual wave,
the sprayer for the flux and the preheating pad. Flux in the wave soldering process has a primary and a
secondary objective. The primary objective is to clean the components that are to be soldered,
principally any oxide layers that may have formed. There are two types of flux, corrosive and
noncorrosive. Noncorrosive flux requires pre-cleaning and is used when low acidity is required.
Corrosive flux is quick and requires little pre-cleaning but has a higher acidity. Preheating helps to
accelerate the soldering process and to prevent thermal shock.

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b) Hand soldering

Fig.2.13 Hand soldering

The first step is the initial work where soldering defects are found out. The defect that has occurred in
wave soldering can be corrected using hand soldering. The defects may be component lift, dry solder,
not soldered, blow hole etc. Hand soldering is to solder very sensitive components like battery, LED,
LCD that cannot be soldered in wave soldering.

There are two types of soldering:

Lead free soldering

Leaded soldering.

Lead free soldering: It does not contain any lead. It contains tin (96.5%), silver (3.0%), and copper
(0.5%). It has more life compared to lead free soldering and also has dull finishing. The melting
point is about 220deg C and setting temperature is 350-375deg C.

Leaded soldering: This soldering method contains lead. It has tin (63%), lead (37%). This soldering
has a shining finishing since it contains tin in it. The melting point is about 180deg C and the setting
point is 280-325deg C.

Fig.2.14 Hand soldering process

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c) Dip soldering

Fig.2.15 Dip soldering process

It is one of the cheapest methods of soldering and is extensively used in small scale industry. The PCBs
are dipped in solder bath and the exposed areas get soldered. The flux should be applied manually. It
consumes less power. Temperature of dip soldering is about 350deg C. The molten bath can be any
suitable filler metal but is usually confined to lower melting point elements. Solder pot metal is made
up of cast iron or steel, electrically heated.

2.4 Lead cutting:

In Lead cutting process extra lead is removed after the Hand soldering and Wave soldering
operation. The extra 2mm of lead is removed as a standard of ISO.

2.5 Cleaning:
It is a process to remove resin and flux from the PCB. Cleaning of PCB typically includes de-
fluxing, but it may also include removing impurities from the board assembly such as solder balls, dirt,
dust, organic materials, and other contaminants.
It is necessary to clean before coating because without removal of flux if coating is done the coating
will not be reliable and leads to corrosion.

The commonly used solvent for cleaning of PCB is Isopropyl Alcohol (IPA) and RO water. For high
level cleaning ABSOL EG and CYBERSOL are used.

Types of cleaning method:

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Point wash:
Few sensitive components like switches, sensors, LCD’s etc. may melt or are damaged due to
high concentration of IPA solution used for cleaning. To avoid this, point wash technique is
used in which the selected points other than the sensitive components on the PCB are washed.
The solvent used is IPA.
Dip wash:
In this technique the PCBs are dipped in IPA for cleaning. The PCB’s cleaned using this
technique should not contain critical or sensitive components.

2.6 Quality Control (QC):

Quality control, or QC for short, is a process by which entities review the quality of all factors
involved in production. ISO 9000 defines quality control as "A part of quality management focused on
fulfilling quality requirements".

This approach places an emphasis on three aspects (enshrined in standards such as ISO 9001.
1. Elements such as controls, job management, defined and well managed processes,
performance and integrity criteria, and identification of records.
2. Competence, such as knowledge, skills, experience, and qualifications.
3. Soft elements, such as personnel, integrity, confidence, organizational culture, motivation,
team spirit and quality relationship.
Inspection is a major component of quality control, where physical product is examined visually (or the
end results of a service are analysed). Product inspectors will be provided with lists and descriptions of
unacceptable product defects such as cracks or surface blemishes for example.
The quality of the outputs is at risk if any of these three aspects is deficient in any way. The aspects
considered in quality control for inspection are Reverse mount, extra mount, component value error,
component damage, component missing is verified & recorded.

2.6.1 Coating:
Conformal coating material is a thin polymeric film which ‘conforms’ to the contours of a
printed circuit board to protect the board's components. It is applied to electronic circuitry to act as
protection against moisture, dust, chemicals, and temperature extremes that, if uncoated (non-

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 PCB Assembling & Designing using SMT Technology & Proteus.

protected), could result in damage or failure of the electronics to function. When electronics must
withstand harsh environments or impact, protection is provided with conformal coatings.

There are 2 types of coating.

I. Brush coating
II. Spray coating.

2.6.1.1 Coating Materials:

➢
Acrylic
Ease of rework
Simple drying process
Good moisture resistance High
fluorescence level

Ease of viscosity adjustment

➢
Polyurethane
Good dielectric properties
Good moisture resistance Solvent
resistance
Less reversion potential

2.7 Final Quality Check (FQC):

The objective of FQC is to ensure the final quality of the product prior to packing. The
features checked here are:

➢ SMD component alignment.

➢ Orientation of PTH components.
➢ Solder ability of SMD and PTH components.
➢ Connector orientation.
➢ Cleaning of PCA’s.
➢ Packing material/method.
➢ Bonding /wiring/ coating if any.
➢ Solder defects if any.

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 PCB Assembling & Designing using SMT Technology & Proteus.

➢ Shorting plugs.
➢ Hardware / mechanical assembly.
➢ Special instruction/ additional requirements from respective customers.
2.8 Packing:
Packing aims at delivery of the product to the customer without any damage.
It is a coordinated system of preparing goods for transport, warehousing, logistics, sale and
end use.
The packing tools are:

➢ Antistatic sheet/ pouches.

➢ Carton box.

➢ Plastic strap.

➢ Strapping tool.

➢ Packing tape.

➢ Customer’s address.

➢ Packing slip.

The packing slip has the details of quantity, customer details, card type, assembly code, date,
DC number, invoice number, form number, revision.
In addition, a ‘To’ and ‘From’ address slip is glued to the packed goods and is dispatched.

2.9 Dispatch:
The packed goods are shipped to the desired address with the required documents.

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 PCB Assembling & Designing using SMT Technology & Proteus.

CHAPTER 3

Advantages and Applications

3.1. Advantages of PCB:

➢ Compact size and saving wire.
➢ Ease of repair and diagnostic.
➢ Saving of time.
➢ Immune to movement.
➢ Tight connections and short circuits avoided.
➢ Low electronic noise.
➢ Low cost. Reliability.

3.2. Applications of PCB:

➢ Automotive industry.

➢ Medical industry.

➢ Lighting and emergency lighting.

➢ Scientific instrumentation.

➢ Marine instrumentation.

➢ Health and safety.

➢ Transport. Agriculture.

➢ Power management. Education.

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Hand’s-on experience

• Manual screen printing of EVM (Electronic Voting Machine), AC controller boards by using
stencil, squeegee.

• Teaching the locations for the components to the bare PCB. Inspection of connectors of EVM
boards after reflowing.

• We manually assembled the through-hole components into the location by using CAD.

• Wave soldering the PCB boards by keeping a desired temperature.

• By using hand soldering method, we soldered LED display of through-hole component.

• Inspection of B3MU by using jig device.

• Cleaning of B3MU, EVM, AC controller using IPA (Iso-Propyl-Alcohol).

• Packing and dispatching the boards by using sink rap cover with ESD protection.

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CHAPTER 4
Conclusion

My internship experience in PCB assembling and designing using SMT technology and Proteus
has been invaluable. I gained practical insights into the intricacies of surface mount technology, honed
my skills in PCB assembly, and deepened my understanding of Proteus for simulation. This hands-on
experience has not only enhanced my technical proficiency but also provided a solid foundation for
future endeavours in electronic design and manufacturing.

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