BASIC HAND SOLDERING MULTICORE SOLDER

Electronics and Computer Systems Engineering

BASIC HAND SOLDERINGBASIC HAND SOLDERING

MULTICORE SOLDER MULTICORE SOLDER most common type for hand most common type for hand

soldering has a composition of soldering has a composition of Tin (Sn60) and Lead (Pb40), Tin (Sn60) and Lead (Pb40), with a diameter of 0.71 mm with a diameter of 0.71 mm

contains internal core of non-contains internal core of non-corrosive Rosin Mildly corrosive Rosin Mildly Activated (RMA) fluxActivated (RMA) flux

has a ‘plastic’ stage between has a ‘plastic’ stage between the melting and solidifying the melting and solidifying

stagesstages

‘‘Dry joints’ are caused through:Dry joints’ are caused through: movement of joint during movement of joint during

‘plastic’ stage‘plastic’ stage thermal stressthermal stress PCB contaminationPCB contamination oxidisationoxidisation



TIPSTIPS appropriate size and width is appropriate size and width is

determined by the size of the determined by the size of the connection to be madeconnection to be made

ideally 2/3 to equal the ideally 2/3 to equal the diameter of the paddiameter of the pad

tips should be correctly 'tinned’ tips should be correctly 'tinned’ at all times, by adding a small at all times, by adding a small

amount of solder to the hot tipamount of solder to the hot tip

Electronics and Computer Systems Engineering BASIC HAND SOLDERINGBASIC HAND SOLDERING

LEAD FORMINGLEAD FORMING minimum distance from the minimum distance from the

end of the component body to end of the component body to the start of the lead bend is the start of the lead bend is usually 2 lead diameters or usually 2 lead diameters or 1.5mm for hand bending 1.5mm for hand bending methodsmethods

without undue pressure hold without undue pressure hold the component lead with the the component lead with the pliers and bend the lead pliers and bend the lead protruding beyond the pliers protruding beyond the pliers with a finger until a 90 degree with a finger until a 90 degree angle is formed.angle is formed.

if damaged discard componentif damaged discard component


COMPONENT MOUNTINGCOMPONENT MOUNTING Radial leadedRadial leaded loaded slightly loaded slightly

off the PCB (0.3 - 3.0mm)off the PCB (0.3 - 3.0mm) Axial-leaded Axial-leaded loaded with the loaded with the

body of the component very body of the component very close to the PCB (0.3 - 3.0mm)close to the PCB (0.3 - 3.0mm)


BENDING AND MOUNTING OF BENDING AND MOUNTING OF COMPONENTSCOMPONENTS

mounted centrally between mounted centrally between the holesthe holes

resistors mounted so colour resistors mounted so colour code orientated in the same code orientated in the same directiondirection

polarised components polarised components should be orientated so that should be orientated so that polarity symbols (+ or - ) and polarity symbols (+ or - ) and component value are visiblecomponent value are visible



LEAD TERMINATIONSLEAD TERMINATIONS

TYPE 1 FULLY CLINCHED –TYPE 1 FULLY CLINCHED – bend the lead flat against the pad bend the lead flat against the pad trim the lead to a length of between 1-2 trim the lead to a length of between 1-2

lead diameterslead diameters Used in High Quality/High Reliability Used in High Quality/High Reliability

military or life support applications military or life support applications difficult to reworkdifficult to rework

TYPE 2 SEMI-CLINCHED –TYPE 2 SEMI-CLINCHED – bend the lead to an angle of approx. 45bend the lead to an angle of approx. 45 Cut to a minimum of 0.5mm and a max. Cut to a minimum of 0.5mm and a max.

of 1.5mm, or between 1-2 lead diameters of 1.5mm, or between 1-2 lead diameters Used for commercial applications Used for commercial applications ease of de-soldering ease of de-soldering

TYPE 3 RIGID LEAD TERMINATION – TYPE 3 RIGID LEAD TERMINATION – straight through terminationstraight through termination Cut to a length of min. 0.5mm and max. Cut to a length of min. 0.5mm and max.

of 1.5mm, or between 1-2 lead diameters of 1.5mm, or between 1-2 lead diameters


CONSTRUCTING A GOOD CONSTRUCTING A GOOD SOLDER JOINTSOLDER JOINT

Figure a) the amount of solder Figure a) the amount of solder applied is minimal and may applied is minimal and may result in a poor electrical result in a poor electrical connection over time.connection over time.

Figure b) shows the optimal Figure b) shows the optimal solder joint that has good solder joint that has good wetting between component wetting between component lead and PCB pad.lead and PCB pad.

Figure c) indicates an Figure c) indicates an excessive amount of solder excessive amount of solder has been applied to the has been applied to the connection.connection.


CLEANINGCLEANING a process of removing

contaminates before and after soldering

ensures good mechanical/electrical connection

Three different methodsThree different methods: Mechanical - scourer or bristle

brush Chemical - solvents eg.

Isopropyl Alcohol Thermal - solder pot



BASIC SOLDERING BASIC SOLDERING PROCEDUREPROCEDURE

iron temperature is set at approx. iron temperature is set at approx. 350350

soldering iron tip size is suitable soldering iron tip size is suitable

solder sponge is damp solder sponge is damp

tip is clean and shiny (wipe & tin)tip is clean and shiny (wipe & tin)

Apply flux (RMA) to help ‘wetting’ Apply flux (RMA) to help ‘wetting’ if necessaryif necessary

soldering iron at a 45soldering iron at a 45 angle angle



BASIC SOLDERING PROCEDUREBASIC SOLDERING PROCEDURE

heat the lead and the pad heat the lead and the pad simultaneouslysimultaneously

flowing solder around the joint flowing solder around the joint forms a heat bridge forms a heat bridge

remove soldering iron and solder remove soldering iron and solder simultaneously (prevents ‘spiking’)simultaneously (prevents ‘spiking’)

clean the PCB with Isopropyl clean the PCB with Isopropyl Alcohol and a bristle brush Alcohol and a bristle brush

wipe or pat dry with a lint free wipe or pat dry with a lint free tissue to remove traces of residue.tissue to remove traces of residue.


Use appropriate safety Use appropriate safety equipment equipment

fume extractorsfume extractors hand cleanershand cleaners gogglesgoggles

READY TO SOLDERREADY TO SOLDER



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BASIC HAND SOLDERING MULTICORE SOLDER