lab 2 - soldering

8/6/2019 Lab 2 - Soldering

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INTRODUCTION TO

SOLDERING



Soldering stand Soldering Gun

Tip@ Bit Heating Element

Wet

Sponge

Bit Sharpener



Soldering Gun¶s or Soldering Iron



Solder, Wet Sponge, Clipper



First Aid

Immediately cool the affected area withcold running water, ice between 2-5

minutes. Apply medicine and seek

professional medical advice where

necessary.

In case you are hurt



Please take all precautions while

using soldering irons.� Never leave your iron plugged in and

unattended.

� Never place your hot iron down on anythingother than an iron stand.

� Replace the cord of your iron if it becomesworn or gets burnt.

� To prevent burning your fingers, use needle

nose pliers or heat resistant gloves to hold smallpieces.



� Soldering is to join electrical parts together to form an

electrical connection, using a molten mixture of lead andtin (solder) with a soldering iron

� Soldering is a manual skill which only comes with

practice and practice.

� Poor soldering can be an expensive business - causing

product failure and wasting time, engineer's maintenance

time and customer dissatisfaction.



Bits:

Bits are very important factor when you are

soldering. Bit is the end portion of thesoldering gun. It is sharp.

Make sure the bit is clean when you aresoldering cause it determine your quality of

soldering. Cleaning the bit each time before

soldering produce a good quality of soldering.



How to Clean the bit?

The solder bit can be

cleaned by using a wet

sponge while the ironis hot. Rock an roll the

tip to the brush to

remove dirt's and

unwanted materials.



Process of Cleaning the Bit

Dirts

Dirty Bit

Solder

Wet Sponge



How to check the bit? Hot or Not!

³Check that the soldering iron is heated

up to the correct temperature by melting a

little solder on to the bit.

The solder should melt immediately to a

shiny surface and white smoke should be

given off.´

This process is called tinning.



Tinning Process

White smoke released



TIPS ON SOLDERING

To produce a good

soldering some importantsteps to follow as outlined

below.



How to Hold a Soldering Iron



Pre-heat the soldering iron for

approximately 3-5 minutes, clean the tip,

and roll the tip on a WET sponge until it

appears bright and shiny.

Procedure 1



Procedure 2

Insert components into the hole of the

PCB and splay or spread the leads so

that the part is held in place and doesn¶t

fall down.



Procedure 3



� Preheat the area tothe soldered by placing the iron tipon the legs andP

CB trace for approximately 2seconds. Makesure to heat both part and the PCBtraces.

Procedure 4



Apply a clean iron tip to the copper andthe lead, in order to heat both items at

the same time.



� K eeping the

Iron in place

bring the

solder to this

area and melt

it for 1-2

seconds.

Procedure 5



Continue heating and apply a few

millimetres of solder. Remove the iron and

allow the solder joint to cool naturally.



� First pull the solder away

Procedure 6



Procedure 7

� Then Pull the Soldering Iron Away



Procedure 8

� Cut the excess lead from the PCB board by

using a cutter



How Good Soldering Looks

What does a good solder connection look

like? A good connection is one where the

solder has uniformly flowed over all the

surfaces to be connected.

The connection appears brig

ht,shiny, and smoot h , wit h all wires in

it appearing well soldered



It only takes a second or two, tomake the perfect joint, which should

be nice and shiny.



A good Quality of Soldering

� It must uniformly

flow in all

direction and it

will look bright

and shinny.



An example of a "dry³ or cold joint -

the solder failed to flow uniformly , and

form globules around the wire.

A Bad Quality of Soldering



Excess of solder, and (extreme left) incomplete

joint with poor coverage, less solder or if the

solder formed into little round blobs or has

sharp points.

Why produce bad soldering?



If the joint is a "cold" connection caused

either by insufficient heat, a wire

moving, or foreign matter(such as

oxides and shaky hands) getting into the

connection:

the cure is simple and direct: re-heat the

joint and apply a little more solder. If that would place too much solder in

the joint, you will have to remove the

solder before trying again.



T ool Used = Desoldering pump@Sucker

De-soldering is required when electronic

components need to be removed from a

circuit, usually because they are faulty. It

may sometimes be necessary during testingor assembly, also if a wrong part has been

fitted or a modification has to be made.

De-soldering Process



The two solder joints to be desoldered,

to enable a faulty component to be

removed.



�

If using a desoldering pump apply the ironfirst to melt the solder (1-2 seconds).

Ensure the pump is 'primed' and ready to

go...



The nozzle of the desoldering pump is applied tothe melted solder and the spring-loaded plunger is

then released (sucker), drawing the solder up into

the pump. Repeat if needed.



The first joint, now desoldered. The

second joint will be desoldered



The component will dropped out of the

board after desoldering. Sometimes, it

may need to be done with pliers.... If it

can¶t be removed.



Close-up shot of both : joints now are

desoldered and ready for the replacement

part to be fitted.



RULES FOR GOOD

SOLDERING�Clean soldering gun or soldering iron frequently.

�Make joint mechanically strong first wherever possible.

�Be sure the soldering gun is hot enough.�Apply solder between heating tip and the component

lead first to speed up the heat transfer.

�Heat the components lead until it melts solder itself.

�Do not use too much solder .

�Avoid burning components.



Use the Right Flux

�Most solder contains flux inside its core,

so the flux is automatically applied when

you heat the solder.

�When it flows over the connection, it

removes oxides from the metal surfaces.

� Any oxides are suspended in the flux,

allowing good metal-to-metal contact.



Here's a summary of how to

make the perfect solder joint.

1.All parts must be clean and free from dirt and

grease.

2.Try to secure the work firmly.

3.Avoid your hand shaking.

4.Clean the tip of the hot soldering iron on a

wet sponge.

5.Many people then add a tiny amount of fresh

solder to the cleansed tip.



6.Heat all parts of the joint with the iron for

under a second or so.

7.Continue heating, then apply sufficient solder

only, to form an adequate joint.

8.Remove and return the iron safely to its stand.

9.It only takes two or three seconds at most, to

solder the average p.c.b. joint.

Do not move parts until the solder has cooled.

lab 2 - soldering

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