High Frequency Attachment; Principles Of Operation - Craftsman 113.201392 Owner's Manual

INERT-GAS METAL-ARC WELDING (Nonconsumabme)
ALL CABLES
SHOULD BE
NEPT SHORT
ASPOSSIBLE
(Donot ex-
ceed12-U2
feetin length)
GROUNDED WORN P IECE ANY CRAFTSMAN WELDER
ORWORN T ABLE MAY BEUSEO W ITH HF
TOELECTRODE / ATTACHMENT
H E ATE WELDER
GROONDCABLE J GROUND
_ - I CABLE o o
230 VOLT
_HOCYCLE
SINGLE PHASE
HIGH FREQUENCY
ATTACHMENT
WELDINGCABLETO WELDER
AC OR DC WELOER
WELDER
CABINET
MOST BE
GROUNDED
F_ure I
(
/ '; \
Figure 2
HmGH FREQUENCY ATTACHMENT
The Craftsman, High-Frequency Attachment may be used
with any Craftsman welder or other single-phase, trans-
farmer-type welder of high quality construction having an
AC, or AC/DC power output Tungsten inert gas (T.kG.)
welding has many useful and advantageous applications
as described in the following paragraphs. In order to use
the T.LG. process w_th an AC welder, a htgh-frequency
attachment must be provided Figure 1 shows a typica_
hookup using this high-frequency attachment with a Crafts-
man welder. When not using the TJ.G. welding process, the
high-frequency attachment also permits easy "arc" start-
ing and greatly improved results with many hard-to-weld
rods (low hydrogen rods) as well as making the welding
operation much easier to perform.
The use of a high-frequency attachment makes possible the
establishment of an arc without touching the electrode to
the work. Once the arc has been estabhshed, it is stabihzed
by the high-frequency output. This is essential in the T.I.G.
process in order to avoid contaminating the tungsten elec-
trade or the work.
PRINCIPLES OF OPERATION
The necessary heat for inert-gas welding (nonconsumable)
is produced by an electric arc maintained between the non-
consumable electrode and the work-piece. The electrode
usedfor carrying the current is usually a tungsten or tungsten
alloy rod. The heated weld zone, the molten metal and the
nonconsumable electrode are shielded from the oxidizing
effects of the atmosphere by a blanket of inert gas fed
through the T.I.G torch and the weld is made by applying
the arc heat untll the abutting edges of the work.pieces are
melted, adding filler rod If necessary. The resultant pool
of molten metal, upon sohdifying, joins the edges of the
members together. The process may also be used for adding
metal to surfaces, locally-melting and spot-jolnlng parts
A thorough cleaning of the surface to be welded is required.
All off, grease, paint, rust, dirt or other contaminants must
be removed either by mechamcal means or by the use of
vapor or hquid cleaners. Files, chisels and stainless wire
brushes may be used Grinding Js not recommended. Liquid
cleaners such as naphtha, mineral spirits, alcohol, acetone
and methyl-ethyl-ketone can be used All surfaces must be
wiped dry with a clean cloth. Cleaners should not be used
after a jo_ntis assembled prior to welding
Striking the arc may be accomphshed as follows
1. Touching the electrode to the work momentardy and
quickly withdrawing it a shortdistance. (DC power source)
2. Use of an apparatus which will cause a spark to jump
without touching the electrode to the work. (AC power
source with high-frequency unit attachment)
The high-frequency arc stabiffzer provides for this latter
method of starting the arc. Such devices are not required
with DC, consequently it is usuafly necessary to touch the
electrode to the work to start the arc.
For manua_ welding, once the arc is started, the electrode
holder is held with the electrode positioned at an angle of
about 75 degrees to the surface of the weld puddle as
shown in figure 2. To start the welding, the holder is usually
moved in a small circle until a pool of molten metal of suit-
able size is obtained. Once adequate fusion ts achieved at
any one point, a weld is made by graduaffy moving the
electrode along the parts to be welded to melt the adloin-
Fng edges progressively, adding filler rod as required
Solidification of the melted metal follows progression of
the arc along the iomt and completes the welding cycle
Material thickness, joint design and weld characterLshcs
desired will determine whether or not filler metal should
be added to the joints. When fll)er metal is added during
manual welding, it is apphed by hand feeding the filler rod
(from the side) into the pool of molten metal in the region
of the arc. Filler rod is added in essentlally the sQmemanner
when welding by the oxyacetylene method