9 | LEARNING TO WELD | 9 |
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MACHINE SET UP FOR THE GMAW (MIG) PROCESS
1.See APPLICATION CHART in the OPERATION section or Application Chart on the inside of wire feed section door for selection of welding wire and shielding gas, and for range of metal thicknesses that can be welded. Also setting the proper con- trols, Drive Roll Orientation and Output Polarity.
2Set the “Voltage” and “Wire Speed” controls to the settings suggested on the Application Guide for the welding wire and base metal thickness being used. The voltage control is marked “V” and the wire feed speed is marked with the icon “olo.’’
3Check that the polarity is correct for the welding wire being used. Set the polarity for DC(+) when welding with the GMAW (MIG) process. See INSTALLATION section of the Operators Manual for instructions for changing polarity.
4.Check that the gas nozzle and proper size liner and contact tip are being used and that the gas supply is turned on. If adjustable, set for 30 to 40 cubic feet per hour (7 to 10 l/min..) under normal conditions, increase to as high as 45 CFH (17 I/min.) under drafty (slightly windy) conditions.
5.Connect work clamp to metal to be welded. Work clamp MUST make good electrical contact to the work piece. The work piece must also be grounded as stated in the “Arc Welding Safety Precautions” at the beginning of the Instruction Manual which is supplied with each welder.
WELDING TECHNIQUES FOR THE GMAW (MIG) PROCESS
Four simple manipulations are of prime importance when welding. With complete mastery of the four, welding will be easy. They are as follows:
1.The Correct Welding Position
Figure 17 illustrates the correct welding position for right handed people. (For left handed people, it is the opposite.)
When GMAW (MIG) welding on sheet metal, it is important to use the “forehand” push technique.
Hold the gun (of the gun and cable assembly) in your right hand and hold the shield with your left hand. (Left handers simply do the opposite.)
FIGURE 17
Push
When using the GMAW process on light gauge mater- ial, weld from right to left (if you are right handed). This results in a colder weld and has less tendency for burn through.
2. The Correct Way To Strike An Arc
WARNING
ARC RAYS can burn eyes and skin.
When using an open arc process, it Is necessary to use correct eye, head and body protection.
Protect yourself and others, read “ARC RAYS can burn” at the front of the Instruction Manual supplied with welder.(ANSI
1.Be sure the work clamp makes good electrical con- tact to the work.
2.Position gun over joint. End of wire may be lightly touching the work.
3.Position face shield to protect face and eyes, close gun trigger, and begin welding. Hold the gun so that the contact tip to work distance is about 3/8 to 1/2 inch (10 – 12 mm).
4.To stop welding, release the gun trigger and pull the gun away from the work after the arc goes out.
5.A ball may form at the tip end of the wire after welding. For easier restrikes, the ball may be removed by feeding out a few inches of wire and cutting off the end of the wire with wire cutters.
6.When no more welding is to be done, close the valve on the gas cylinder, momentarily operate the gun trigger to release gas pressure, then turn off the machine.
