Jasic MIG SERIES - MIG Controls Overview; Wire Feed Speed Control; Voltage Setting Guide

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GUIDE TO MIG/MAG WELDING
Before starng any welding acvity ensure that you have suitable eye protecon and
protecve clothing. Also take the necessary steps to protect any persons within the welding
area.
MIG controls
The controls for the MIG/MAG system are as follows. Controls can be electro mechanical or electronic but
the eects will be the same.
Wire feed speed
The wire speed is directly related to the current. The higher the wire speed the more wire is deposited
and hence more current is required to burn o the consumable wire.
Wire speed is measured in m/min (metres per min) or somemes in ipm (inches per minute).
The diameter of the wire also forms part of the current demand e.g. a 1.0mm wire feeding at 3m per min
will require less current than a 1.2mm wire feeding at the
same rate.
The wire feed is set according to the material to be
welded.
If the wire feed rate is too high in comparison to the
voltage then a “stubbing” eect happens where unmelted
consumable contacts the work piece creang large
amounts of weld spaer.
Too lile wire feed comparison to the voltage will result in
a long arc being created with poor transfer and eventual
burning back of the wire onto the contact p.
Wire Speed Voltage Mode Switch
Voltage seng
The voltage polarity in MIG/MAG welding is in the majority of cases with the posive (+). This means
that the majority of the heat is in the electrode wire. Certain special wires may require the polarity to be
reversed i.e. electrode wire negave (-) polarity. Always consult the manufacturer's data sheet for the
best operang parameters.
The voltage is oen referred to as the “heat seng”. This will be altered dependent on the material type,
thickness, gas type, joint type and posion of the weld. Combined with the wire speed it is the main
control adjusted by the welder. The voltage seng varies depending on the type and size of electrode
wire being used.
Most MIG/MAG welders are CV or Constant Voltage power sources which means the voltage does
not vary much during welding. Modern inverter power sources also have control circuits to monitor
condions to ensure voltage remains constant.
The voltage determines height and width of the weld bead. If the operator has no reference to sengs
required the best method of set up is to use scrap material of the same thickness to obtain the correct
seng. If there is too much voltage the arc will be long and uncontrollable and cause the wire to fuse
to the contact p. If the voltage is too low then there will not be enough heat to melt the wire and then
stubbing occurs.
To obtain a sasfactory weld a balance needs to be made between voltage and wire speed.
Characteriscs of the voltage are that the higher voltage produces a aer and wider weld bead but
care must be taken to avoid undercut. The lower the voltage the weld bead becomes narrow and higher.