11.3 Tools for MMA
Common tools for MMA include electrode holder, welding mask, slag hammer, wire brush (see
below), welding cable and labor protection equipment.
a) electrode holder b) welding helmet c) slag hammer d) wire brush
Tools for MMA
1) Electrode holder: a tool for clamping electrode and conducting current, mainly including 300A type
and 500A type.
2) Welding mask: a shielding tool for protecting eyes and face from injuring due to arc and spatter,
including handholding type and helmet type. Colored chemical glass is installed on the viewing window
of the mask to filter ultraviolet ray and infrared ray. Arc burning condition and weld crater condition can
be observed from the viewing window during welding. Thus, welding can be carried out by operators
conveniently.
3) Slag hammer (peen hammer): for the use of removing slag crust on the surface of weld joint.
4) Wire brush: for the use of removing dirt and rust at the joints of the workpiece before welding, as well
as cleaning the surface of weld and the spatter after welding.
5) Welding cable: generally cables formed from many fine copper wires. Both YHH type arc welding
rubber sleeve cable and THHR type arc welding rubber sleeve extra-flexible cable can be used.
Electrode holder and welding machine are connected via a cable, and this cable is named as welding
cable (live wire). Welding machine and workpiece are connected via another cable (earth wire). The
electrode holder is covered with insulating material performing insulation and heat insulating.
11.4 Basic Operation of MMA
a. Welding joint cleaning
Rust and greasy dirt at the joint should be removed completely before welding in order to implement
arc igniting and arc stabilizing conveniently as well as ensure the quality of weld joint. Wire brush can be
used for condition with low requirement on dust removal; grinding wheel can be used for condition with
high requirement on dust removal.
b. Posture in operating
Take flat welding of butt joint and T-shaped joint from left to right as an example (See below). The
operator should stand at the right side of the working direction of weld joint with mask in the left hand and
electrode holder in the right hand. The left elbow of the operator should be put on his left knee to prevent
his upper body from following downwards, and his arm should be separated from the costal part so as to
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