Introduction - Snap-On MUSCLE MIG SYSTEM MM350XL Owner's Manual

INTRODUCTION

The Snap-on Tools MM350XL is a
combination welding power source,
remote feed unit, MIG torch and
accessory package, which is de-
signed to meet the requirements of
the light to heavy metal fabrica-
tion industries. The MM350XL pro-
duces fusion welds by the Gas Metal
Arc Welding process (GMAW or MIG),
on steel and aluminum up to "1/2"
thick, using .023" through 1/16"
steel wire and .023" through 3/64"
aluminum wire with the optional
MHG5-B spool gun. (optional liners
and drive rolls must be purchased to
cover all given wire types and
sizes). Heavier sections can be
easily welded using slightly dif-
ferent techniques.
The number of controls on the unit
have been reduced to assist inexpe-
rienced operators
welding. This facilitates rapid
set up for welding various thick-
nesses of material requiring vari-
ous heat inputs.
control adjusts the welding voltage
and the WIRE FEED control adjusts
the speed of the wire feed motor.
THE MIG PROCESS
AS APPLIED TO THE MM350XL
The MIG process uses a bare,
consumable electrode in the form of
spooled wire, which is fed by a
controllable
through the cable and torch to the
weld. The emerging wire and the
weld are shielded by a stream of
CO2, Argon, or a mixture of the two,
which prevents oxidation of the
molten weld puddle. The gas shield
enables high quality welds to be
made without
eliminating the need for slag or
flux removal after the weld is
completed.
to learn
The VOLTAGE
speed feed unit
the use of flux,
MIG
TORCH
SHIELDING GAS
WORK
FIG. 1. SCHEMATIC OF M.I.G. PROCESS
The consumable electrode wire is
melted and transferred to the weld
puddle by any of three arc modes;
short arc transfer, globular trans-
fer, or spray arc transfer. The
MM350XL is capable of performing
all modes.
MIG
SHORT ARC OR DIP TRANSFER
Short arc transfer occurs at 12 to
22 arc volts (voltage while weld-
ing), depending on wire size. Weld-
ing commences as the arc is struck
and a weld pool is formed. The tip
of the electrode wire dips into the
pool and causes a short circuit.
The short
causes a rapid temperature rise in
the electrode wire and the end of
the wire is melted off.
immediately formed between the tip
of the wire and the weld pool,
maintaining the electrical circuit
and producing sufficient heat to
keep the weld pool fluid.
electrode continues to feed and
again dips into the pool.
ELEC-
TRODE
WORK
FIG. 2. SHORT ARC TRANSFER
4
WIRE SPOOL
FEED
ROLLS
POWER SOURCE
REVERSE
POLARITY
circuit current
An arc is
+
(STD.)
_
flow
The