2. An arc welding process that uses an arc between a
continuous filler metal electrode and the weld pool to
produce a fusion (melting) together of the base metal
The process is used with a shielding gas supplied from
an external source without pressure.
3. Wire Feed
MIG = Metal Inert Gas
Inert Gas= Inactive gas that does not combine chemically with base
or filler metal
MAG= Metal Active Gas
Active Gas= Gas will combine chemically with base or filler metal
4. Advantages
Variety of Metals
All Position Welding
Quality Welds
No Slag
Low Spatter
Disadvantages
Cost
Not portable
Easy to lack of fusion
Not suitable for
windy conditions
Only for clean Base
Material
5. Cover all skin to prevent Radiation burns
Cover hair to prevent sparks setting hair on fire
Wear ear plugs to protect from noise and burning
ear drums with sparks
Use a 14 shade welding helmet to protect eyes
Wear safety glasses at all times
Make sure pants pockets are empty
6. Power Supply
Direct Current Electrode Positive (DCEP)
(Electrons flow from – to +)
Wire Feeder
Electrical mechanical device that feed required amount
of filler material at a constant rate of speed
7. Welding filler electrode
Small diameter consumable electrode that is supplied to
the welding gun by the roller drive system
Shielding Gas
Gas used to protect the molten metal from atmospheric
contamination :
75%Argon (inert gas) & 25% Carbon Dioxide most
common gas used for GMAW
8.
9. A. Hand wheel
B. Flow meter
C. Wire spool
D. Wire
E. Feed roll tension
F. Voltage meter
G. Wire speed meter
H. Wire speed adjustment
I. Voltage adjustment
J. Power switch
K. Gun cable
L. Gun
M. Ground clamp
N. Ground cable
O. Feed rolls
P. Wire guide
Q. Wire overrun
R. Safety nut
10.
11. Plug ground wire into (Neg) Terminal
Plug Wire Feeder into (Pos) Terminal
Select CV-Wire mode
Hot start is not used
Set Arc Control to “-5”
-10= soft arc (for use with inert gases)
+10= crisp arc (for use with CO2)
(See Next Slide)
12. Min. Arc Control
• Soft Arc
• Thicker Materials
• Deeper Penetration
• More Fluid Weld Pool
• Flatter / Smoother Weld
• Reduce Spatter
• Stainless Steels
Max Arc Control
• Crisp Arc
• Thin Materials
• Arc Stability On Open Gaps
• Convex Weld Bead
• Increased Spatter
• Colder Arc
• Improved Weld Pool Control
13. Set Volts
See Chart for proper setting
Set Wire Speed
See Chart for proper setting
Increase wire speed = Increase amps
Decrease wire speed = Decrease amps
Set gas flow
See Chart for proper setting
Pull trigger to get gas flowing then adjust regulator
14. Hold tip 1/16” to 1/8” from work piece
Angle of tip should be 10-15°
Can push or pull bead
Pull (preferred)
More stable arc
Less Spatter
Deeper penetration
Push
More spatter
Less penetration
Good cleaning action
15.
16. Possible Causes Corrective Actions
* Drive Rolls in Poor Condition *Tighten, Clean, or Replace
Drive Rolls
* Excessive Welding Voltage * Reduce Voltage
* Insufficient Electrical Stickout* Increase Contact Tip to Work
Piece Distance
* Contact Tip in Poor Condition * Clean or Replace Contact tip
* Spatter on Contact Tip * Remove Spatter
17. Possible Causes Corrective Actions
* Excessive Amperage *Reduce Amperage
* Improper Travel Angle *Use a Push Angle
*Travel Speed Too Low *Increase Travel Speed
* Insufficient Electrical Stickout *Increase Contact
Tip to Work Distance
18. Possible Causes Corrective Actions
* Insufficient Amperage *Increase Amperage
* Improper Travel Angle * Use Less of a Drag angle
* Excessive Electrical Stickout * Decrease Contact Tip to
Work Piece Distance
* Weld Joint Too Narrow * Increase the Opening of
the Weld Joint