BASIC HAND SOLDERING

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• BASIC HAND SOLDERING
• MULTICORE SOLDER
• most common type for hand soldering has a
  composition of Tin (Sn60) and Lead (Pb40), with
  a diameter of 0.71 mm
• contains internal core of non-corrosive Rosin
  Mildly Activated (RMA) flux
• has a plastic stage between the melting and
  solidifying stages

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• Dry joints are caused through
• movement of joint during plastic stage
• thermal stress
• PCB contamination
• oxidisation

BASIC HAND SOLDERING
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BASIC HAND SOLDERING

• TIPS
• appropriate size and width is determined by the
  size of the connection to be made
• ideally 2/3 to equal the diameter of the pad
• tips should be correctly 'tinned at all times,
  by adding a small amount of solder to the hot tip

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BASIC HAND SOLDERING

• LEAD FORMING
• minimum distance from the end of the component
  body to the start of the lead bend is usually 2
  lead diameters or 1.5mm for hand bending methods
• without undue pressure hold the component lead
  with the pliers and bend the lead protruding
  beyond the pliers with a finger until a 90 degree
  angle is formed.
• if damaged discard component

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BASIC HAND SOLDERING

• COMPONENT MOUNTING
• Radial leaded loaded slightly off the PCB (0.3 -
  3.0mm)
• Axial-leaded loaded with the body of the
  component very close to the PCB (0.3 - 3.0mm)

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BASIC HAND SOLDERING

• BENDING AND MOUNTING OF COMPONENTS
• mounted centrally between the holes
• resistors mounted so colour code orientated in
  the same direction
• polarised components should be orientated so that
  polarity symbols ( or - ) and component value
  are visible

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BASIC HAND SOLDERING

• LEAD TERMINATIONS
• TYPE 1 FULLY CLINCHED
• bend the lead flat against the pad
• trim the lead to a length of between 1-2 lead
  diameters
• Used in High Quality/High Reliability military or
  life support applications
• difficult to rework
• TYPE 2 SEMI-CLINCHED
• bend the lead to an angle of approx. 45?
• Cut to a minimum of 0.5mm and a max. of 1.5mm, or
  between 1-2 lead diameters
• Used for commercial applications
• ease of de-soldering
• TYPE 3 RIGID LEAD TERMINATION
• straight through termination
• Cut to a length of min. 0.5mm and max. of 1.5mm,
  or between 1-2 lead diameters

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BASIC HAND SOLDERING

• CONSTRUCTING A GOOD SOLDER JOINT
• Figure a) the amount of solder applied is minimal
  and may result in a poor electrical connection
  over time.
• Figure b) shows the optimal solder joint that has
  good wetting between component lead and PCB pad.
• Figure c) indicates an excessive amount of solder
  has been applied to the connection.

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BASIC HAND SOLDERING

• CLEANING
• a process of removing contaminates before and
  after soldering
• ensures good mechanical/electrical connection
• Three different methods
• Mechanical - scourer or bristle brush
• Chemical - solvents eg. Isopropyl Alcohol
• Thermal - solder pot

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BASIC HAND SOLDERING

• BASIC SOLDERING PROCEDURE
• iron temperature is set at approx. 350?
• soldering iron tip size is suitable
• solder sponge is damp
• tip is clean and shiny (wipe tin)
• Apply flux (RMA) to help wetting if necessary
• soldering iron at a 45? angle

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BASIC HAND SOLDERING

• BASIC SOLDERING PROCEDURE
• heat the lead and the pad simultaneously
• flowing solder around the joint forms a heat
  bridge
• remove soldering iron and solder simultaneously
  (prevents spiking)
• clean the PCB with Isopropyl Alcohol and a
  bristle brush
• wipe or pat dry with a lint free tissue to remove
  traces of residue.

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BASIC HAND SOLDERING

• Use appropriate safety equipment
• fume extractors
• hand cleaners
• goggles
• READY TO SOLDER