Jasic EVO 2.0 EM-200CT, Operator'S Manual

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GUIDE TO MIG/MAG WELDING
Before starting any welding activity ensure that you have suitable eye protection and
protective clothing. Also take the necessary steps to protect any persons within the welding
area.
Welding Mode - Standard
Current or wire feed speed, workpiece thickness adjustment has no relation with voltage adjustment
and other parameters. In this modes all required parameters are to be set as separate settings.
Please see wire speed and voltage setting above.
Some quick reference handy tips for the MIG/MAG welding process are:
•
When welding, try to use an electrode stick out (the distance between the weld and the contact tip)
of around 6
- 8mm
•
When welding thin materials try and use smaller MIG wire diameters and for thicker materials use
thicker wires
•
Make sure you select the correct MIG wire type for the material to be welded
•
Ensure the MIG welding gun has the correct sized contact tip and type of liner
•
Always ensure you have the correct size drive rolls and torch liner for the wire size selected
•
Select the correct gas to achieve the correct weld characteristics and finish
•
For optimum control of the weld keep the wire at the leading edge of the weld pool
•
Before commencing welding, ensure a comfortable and stable position
•
Try to keep the welding torch as straight as possible when welding to ensure the best feed
•
Carry out daily housekeeping on the condition of the welding torch and drive rolls
•
Keep any consumables clean and dry to avoid contamination such as oxidation and damp
Inductance
When MIG/MAG welding in the dip transfer mode the welding wire electrode touches the work piece/
weld pool and this results in a short circuit. When this short circuit occurs the arc voltage will fall to nearly
zero. This change in the arc voltage will cause a change in the welding circuit.
The fall in voltage will cause a rise in the welding current. The size of the current rise is dependent upon
the welding characteristic of the power source.
Should the power source respond immediately then the current in the circuit would rise to a very high
value. The rapid increase in current would cause the short circuited welding wire to melt similar to an
explosion creating a large amount of molten weld spatter.
By adding inductance to the weld circuit this will slow down the rate of current rise. It works by creating
a magnetic field which opposes the welding current in the short circuit thereby slowing the rate of rise.
If the inductance is increased it will cause an increase in arc time and reduction in the dip frequency,
this will help reduce spatter.
Depending on the welding parameters there will be an optimum inductance setting for the best welding
conditions. If the inductance is too low then there will be excessive spatter. If the inductance is too high
the current will not rise high enough and the wire will stab the weld pool with insufficient heat.
The modern technology welding power sources often have the ability to provide the correct inductance
to provide excellent weld characteristics. Many have a variable inductance control to give precise control.