MIG Welding

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MIG Welding

• A quick overview and how to!

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What does MIG Stand for?

• METAL- the metal electrode.
• INERT- is non-active, does not burn.
• GAS- shields the weld from impurities.

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Objectives

• Students will be able to
• describe and list the different parts of a MIG
  welder.
• state the steps in making a successful MIG weld.
• provide properties of a good weld.

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• Parts of a MIG welder
• How to make a good weld
• Properties of a good weld

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The Parts of a MIG Welder

• Gun
• Is the part of the welder that feeds the wire
  electrode and makes the current contact.
• Controls the on and off of the wire feed and
  power.
• Is usually hand held but can be operated
  robotically.

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Wire

• Is the fill material as well as the electrode for
  the MIG welder.
• Can be either Flux Core wire of Solid wire.
• Flux Core wire

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Flux Core Wire

• Is a type of wire used in wire feed welders that
  do not require gas to shield the weld.
• The wire has a flux core similar to the coating
  on a welding rod to shield the weld from
  impurities, the core is usually surrounded by
  mild steel.
• Solid wire must have a gas shielding it.

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Whip and Liner

• The whip is the hose that transfers the wire
  and gas to the gun it contains the liner.
• The liner is the flexible tube that allows the
  wire to be fed through and remain flexible
  similar to brake cable liner.

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Ground Cable and Clamp

• The Ground Cable is the cable that connects to
  the work through the ground cable to complete the
  circuit that melts the electrode.
• The Ground Clamp fastens to the work allowing a
  temporary transferable method of connecting.

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Wire Feeder

• The Wire Feeder consists of small motor and
  feeder wheels that are controlled by the gun.
• The rollers feed the wire through the whip to the
  gun.

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Welder Case and Controls

• The Welder Case houses the wire feeder,
  transformer, and controls.
• The Controls determine the voltage and wire feed
  speed on most welders.
• Back to Top

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How to make a good MIG weld.

• Flat weld
• hold the gun at a 90 degree angle to the work
  piece, directing the filler metal straight into
  the joint.
• Use a small weaving pattern back and forth across
  the joint.

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Additional things to keep in mind.

• The heat you use when welding is very important.
  This is dependent on the material being welded,
  the type of weld and the thickness of the
  material.
• If it is too hot, the weld will burn through the
  material.
• It if is not hot enough the weld will not
  penetrating the material and will produce a weak
  weld.
• The wire speed needs to be set so the desirable
  weld is a good consistency.
• If the wire speed is too fast the weld will be a
  lumpy, and the welding will be difficult.
• If it is too slow, there will not be enough
  filler in the weld to make it strong.
• Back to top.

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Properties of a good weld.

• A good weld is
• looks even and uniform.
• has the proper penetration.
• Is evenly dispersed over the joint.
• has no holes.
• is appealing to the eye.
• back to top

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Summary

• What are the parts of a MIG welder?
• What are the steps to take to make a good weld?
• What are the properties of a good weld?