Mma Welding; Filler Materials And Equipment; Earth Return Cable And Clamp; Manual Metal Arc Welding (Mma) - Kemppi Master S 400 Operating Instructions Manual

3.3

MMA welding

In manual metal arc welding (MMA), the filler material is melted from the electrode to the
weld pool. The rate of welding current is selected on the basis of the electrode size and
welding position. The arc forms between the electrode tip and work piece. The melting
electrode coating forms a gas and slag shield, which protects the molten metal in transfer
to the weld pool and during solidification. As the slag solidifies over the hot weld metal, it
prevents weld metal from oxidation. This slag coating is removed after welding e.g. with a
chipping hammer. When removing the slag coating, ensure you protect your eyes and face
with suitable equipment.
For more info, visit www.kemppi.com > Welding ABC.

3.3.1 Filler materials and equipment

Master S series can be used with most of the common electrode types for DC welding. For
welding with cellulosic electrodes, the optional kit should be fitted. Electrode sizes for the unit
are listed in Technical data section later in this manual. Follow the welding specifications given
on the electrode package.
1. Check that the welding cable and earth return cable connections are hand tight.
If a cable connection is loose, it will result in a decrease of welding performance,
overheating of the connection, and it may affect your product warranty cover.
2. Select and mount the correct electrode type firmly in holder.

3.3.2 Earth return cable and clamp

If possible, always fix the earth return cable and clamp directly to the welding work piece.
1. Clean the connection surface of the clamp from paint, dirt and rust.
2. Connect the clamp carefully so that contact surface is as large as possible.
3. Finally check that the clamp remains fastened.

3.3.3 Manual metal arc welding (MMA)

Select your required welding parameters according to the manufacturer's filler material
recommendations and the joint to be welded.
1. Select the required polarity (+ or –) of welding current cable (normally + ) and
earth return cable (normally –) according to the filler material manufacturers
recommendations.
2. Select MMA welding mode by pressing the process selection button on the control
panel.
3. Select a suitable welding current by adjusting the current adjustment knob.
4. Make a small test weld to check the selections made.
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