welding

amperage

measurement of how many electrons go past a point

voltage

electrical force or pressure that cause electrons to flow

resistance

oppositon to the electron flow

watts

unit of electrical power

voltage again?

An electric potential difference between two points on a conducting wire

What is current again?

Negatively charged particles which flow from the voltage source through conductive material to a ground

What is resistance again?

The opposition that a material offers to the passage of an electrical current

So what is Ohm’s Law again?

• It is a mathematical equation explaining the relationship between Voltage (E), Current (I) and Resistance (R) within electrical circuits

MIG Welding

• Stands for “Metal Inert Gas”

• GMAW is the official name

  • Stands for “Gas Metal Arc Welding”

• Done manually or robotically

MIG Welding

• Process uses a solid wire electrode that is continuously fed into the weld pool

  • The wire electrode is consumed and becomes the filler metal

Advantages of MIG

• Very versatile

• Easy to learn

• Puts down a lot of metal quickly 

(lbs per hour)

• more than SMAW or GTAW

• for every pound of solid wire electrode wire used, 92-98% becomes deposited weld metal

  • SMAW is around 60-70%

Shielding Gas

• Inert Gas

  • doesn’t react to anything

• We use 75% Argon, 25% CO2

• Can also use Helium, Hydrogen & Oxygen

Variables

1. Shielding gas

2. Voltage (heat)

3. Wire Speed (penetration)

   • inches per minute

   • set by amperage

     • increase in wire speed = increase in amps

4. Travel Speed

5. Travel Angle - 15°

1. Pushing – thin metal

2. Pulling – THICK metal

how Exactly does Voltage Affect Bead Width?

lower arc voltage smaller

higher arc voltage bigger with

Polarity

• Uses DCEP, aka DCRP

• DCEN is rarely used

• AC never used

Duty Cycle

• duty Cycle:  amount of time you can run a machine at full power

  • 10 minutes = 100%

Power Source

• CC:  Constant Current

  • used in GTAW & SMAW welding

  • voltage varies by arc length

• CV:  Constant Voltage

  • How you set a MIG

  • VC =Variable current

  • Usually set around 18-20 V, 

   then adjust from there

another name fordcen

reverse polarity

dcep is known as

reverese polarity

revers polarity is also known as

dct

straight polarity is also known as

dc

another name for DCT is

negative polarity

another name for DCT is

DCEP

true or false polarity is in regard to the amount of current flowing

false

true or false polarity is in regard to the direction of current

true

dcrp is also known as

dc-

positve polarity is also known as

dc-

negative poalirty is also known as

dcrp

if you want to use dc- your gun should be plugged into the

negitve

another name for DCT+

dcrp/ reverse polarity/dcep/positve

true or false amperage refers to the pressure behind the current

false

the unit of electrical measurement describes the amount of current

amp

measurement describes electrical power

watt