Soldering is done using solder while brazing is done using a
lower melting-temperature filler metal. In welding, the base
metal also melts while joining two metals whereas this is
not the case with soldering and brazing.
Before we proceed with soldering, let us understand some
of the basics:
RoHS: Restriction of
Hazardous Substances [ lead (Pb), mercury (Hg), cadmium
(Cd), hexavalent chromium (CrVI), polybrominated
biphenyls (PBB) and polybrominated diphenyl ethers (PBDE).]
Waste from Electrical and Electronic Equipments.
Solder with NO Lead (Pb).
Static electricity or ESD
is an electrical charge that is at rest. This is mainly
created by an imbalance of electrons that stay on a
specific surface, or in the environmental air. The
imbalance of electrons (in all cases, is caused by
absence or surplus of electrons) thus causes an
electrical field that is capable of influencing other
objects at a distance.
Flux – Types and Role of Flux in Soldering: Flux
plays a vital role in any soldering process and
PCB assembly. Flux removes
any oxide and prevents oxidation of metals and hence
helps in better soldering quality. There are
basically three types of Flux used in Electronics:
R Type flux
- These flux are Non-Activated and are used where there
is least oxidation.
RMA Type Flux
- These are Rosin Mildly Activated Flux. These fluxes
are more active than R-Type fluxes and are used at
places where there is more oxidation.
RA Type Flux
- These are Rosin Activated Flux. These are very active
flux and are used at places that have too much
Solder – Types and Role of Solder in Soldering:
Solder is the life and blood of any PCB. The quality of
solder used during soldering and PCB assembly decides
the life and performance of any electronic machine,
consumer electronics, appliance or gadget. Different alloys of
solder are available but the real ones are those that
are eutectic. Eutectic solder is one that melts exactly
at the temperature of 183 Degree Celsius. An alloy of
tin and lead in the ration 63/37 is eutectic and hence
63/37 tin-lead solder is called eutectic solder. Solders
that are non-eutectic will not change from solid to
liquid at 183 Degree Celsius.
Solder is available in
These are called solder wire and are available in
various combinations of alloy and in various diameters
ranging from 0.2 to 1.5mm. Solder wire is basically used
in hand soldering.
Solder bars are in the form of bar is sizes of .5 to 1
kg. Solder bar is used in wave soldering.
As the name suggests, these are solder in predefined
shapes and sizes depending on the soldering requirement.
They can be circular, triangular, rectangular or square
or in any other shape.
These are soldering in paste form. Solder paste is used
in Reflow Soldering and Hot Air Soldering.
These are solder in the form of tiny balls in sizes
ranging from 18 to 30 MIL. Solder balls are used in BGA
of Ball Grid Array soldering. Most of the tiny gadgets
There are two types of electronic
Active and Passive Electronic Components.
are those that have gain or directionality. E.g.
transistors, integrated circuits or ICs, logic gates.
Passive electronic components
are those that do not have gain or directionality. They
are also called Electrical elements or electrical
Inductors. Again, electronic components can be in
thru-hole of SMD (Surface Mount Devices or Chips).
soldering can be done the 3 ways:
: Wave soldering is done for mass production. Equipments
and raw materials needed for wave soldering are - wave
soldering machine, solder bar, flux, reflow checkers,
dip tester, spray fluxer, flux controller.
Reflow Soldering is done for mass production and is
used for soldering of
SMD components on to the PCB.
Equipments and raw material needed for reflow soldering
are - Reflow Oven, Reflow checker, stencil printer,
solder paste, flux.
Hand soldering is done in small scale production and
repair and rework of PCB. Equipments
mobile phone repairing. Raw materials
needed in hand soldering are - Soldering iron,
station, solder wire, solder paste, flux, desoldering
iron or desoldering station, tweezers, solder pot, hot
air system, wrist straps, smoke absorbers, static
eliminators, heating gun, pick-up tools, lead formers,
cutting tools, microscopes and magnifying lamps, solder
balls, flux pen, Desoldering braid or wick, desoldering
pump or sppon, overcoat pen, ESD material.
Another form of electronic components are
BGA or ball
Grid Array. They are special components and need
special soldering. They do not have any leads coming
out , rather they used solder balls used under the
component. Because the solder balls have to be placed
under the component and soldered, soldering of BGA
becomes a very difficult task. BGA Soldering need BGA
Soldering and rework Systems and solder balls.