Welding
Welding is a method of joining metal parts and includes:
-
Gas metal arc (MIG).
-
Gas tungsten arc (TIG).
-
Spot.
 
MIG:
Electric arc welding process in which an arc is struck between a consumable wire electrode
and a work piece. Shielding is provided by an inert gas, hence MIG for Metal Inert Gas. The electrode melts within
the arc and is deposited as filler material. A shielding gas is provided throughout the
process to protect the weld from atmospheric contamination during solidification.
TIG:
Electric arc welding process in which an arc is struck between a non-consumable tungsten
electrode and the work piece. Shielding is provided by an inert gas, hence TIG for
Tungsten Inert Gas. A shielding gas is provided at low pressure and forms a protective
shield around the arc and the molten pool of metal. The tungsten electrode is not consumed
because of its extremely high melting point. Filler material is supplied as a wire or
rod.
Spot:
Process in which contacting metal surfaces are joined by the heat obtained from resistance
to electric current flow. Workpieces are held together under pressure exerted by
electrodes.
There are three stages in making a spot weld. During the first stage, electrodes are
brought together against the metal, and pressure is applied. Next, the current is turned
on momentarily. This is followed by the third, or hold, stage, in which the current is
turned off, but the pressure is continued. This hold time forges the metal while it is
cooling.
Possible shapes
Most.
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Example parts
Boxes, tubes, covers, brackets, cases etc.
Advantages of Welding
Low cost process to join parts permanently and with strength.
Specifications for Welding
 Material - MIG: Most
types of metals. TIG: aluminum, magnesium, stainless steel, titanium, nickel alloys.
Spot: aluminum, brass, cast iron, mild steel, stainless steel, magnesium.
Alternative machines
- additional holes in design for bolting parts together.
Tooling - No special
tooling is needed.
Reducing costs - Reduce total weld length.
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Notes
 MIG: best in
flat horizontal position
TIG: well suited for thin metals, exotic materials, small parts - high quality precision
welds
Spot: Lowest cost.
Processes: Turning
Milling
Laser Cutting
Water Jet Cutting
Wire EDM
Tapping
Bending
Turret Punching
Fine Blanking
Blanking
Steel Rule Die Cutting
Drawing
Injection Molding
Extrusion
Metal Casting
Thermoforming
Forging
Springs
Wire forming
Powder Coating
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