
Orbital Weldhead
Owner’s Manual
Product: Mini Micro
Manual: 091-0510
Serial: 02020001
Voltage Rating: N/A
Revision: May 2002 Rev A
Model Number: 4000

trained and experienced in the use and
without adequate training in the use of
from many public and private schools or
tion and maintenance of this equipment
with the equipment, and the use of
welding power sources, compressed
VIOLET RADIANT ENERGY WHICH
Wear helmet with safety goggles or
tected by clear cover glass). This is a
to protect the eyes from radiant energy
when broken, pitted, or spattered.
Wear protective clothing - leather (or
to avoid entry of sparks and slag.
Avoid oily or greasy clothing. A spark
WARNING: The use of this product may
to the State of California to cause cancer
Adequate ventilation. Severe discomfort,
vapors, heat, or oxygen enrichment or
ventilation. NEVER ventilate with oxygen.
welded or cut, may produce harmful con-
that emit toxic fumes should not be heated
Work in a con ned space only while it is
wearing an air-supplied respirator.
the space is safe before reentering it.
Vapors from chlorinated solvents can be
ame) to form PHOSGENE, a highly toxic
welding or cutting atmosphere or where
the radiant energy can penetrate to atmo-
trichloroethylene or perchloroethylene.
ying sparks, hot slag, or heated mate-
through wall or oor openings, out of
free of oil, grease, and (in electrical
to an area free of combustibles. Avoid
Walls touching combustibles on opposite
Walls, ceil in gs , and floor near work
Appreciable combustibles (including
Appreciable combustibles are further
than 35 feet, but can be ign it ed by
oors or walls within 35 feet may expose
After work is done, check that area is
free of sparks, glowing embers, and
An empty container that held combus-
tibles, or that can produce ammable or
toxic vapors when heated, must never

washing, depending on the combustible’s
Water- lling just below working level may
A cont ainer with unk nown conten ts
vented before welding or cutting. They
the regulator was designed.
valve). The following symptoms indicate
faulty regulators for repair to manufac-
turer’s designated repair center, where
valves, or safety devices:
Avoid electr ical circui t cont act with
wires, or welding circuits. They can
to a serious accident. (See 1-3C)
when the cylinder is properly handled.
from FULLS, and return promptly.
wrench to open a cylinder valve that cannot
than that designed for the speci ed gas.
A general hose identi cation rule is: red
for fuel gas, green for oxygen, and black
Avoid long runs to prevent kinks and abuse.
Wipe with a clean, lintless cloth.
for a particular gas or gases to a cylinder
threaded connections, clean and smooth
Adapters. Use a CGA adapter (available
from your supplier) between cylinder
two wrenches to tighten adapter marked
for oxygen and left hand threads (with
tor pressure increases slowly. When
than one turn to permit quick emergency
your supplier) for safe and effi ci en t
from service immediately for repair. Read

from light-colored surfaces, and burn
the skin and eyes. Skin burns resemble
Wear long-sleeve clothing in addition to
when exposed to the electric arc, even
when not looking in the direction of the
Welding helmet or shield containing a
lter plate shade no. 12 or denser must
welding, a separate room or enclosed
tible screens or panels. Allow for free air
Viewing the weld. Provide face shields for
to the outside air. Carbon monoxide can
water, or moi sture betw een body and
When installing, connect the frames of
the building ground. Conductors must be
two wires of the three-phase line. Do NOT
the thir d (live) wire, or the equipment
will become electrically HOT - a danger-
tion to a switch box, connect the ground
three-prong plug is added for connection
to a grounded mating receptacle, the
with a three-prong plug, connect to a
with damaged areas may be taped to
when the power switch of gas metal-arc
welding equipment is ON and welding
welding power source, and pull all 115

When this equipment is shipped, title passes to the purchaser upon receipt
___________________________________
___________________________________
________________________________________
Whenever requesting replacement parts or information on this equipment,

Table of Contents
Arc Start Troubleshooting
Appendix B Locating Mandrels
Appendix C Pre-Ground Tungsten Electrodes

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with the CobraCooler™ installed
Advanced Color Logic™ (ACL) orbital power-supply. The cable assembly
ow, and recirculating coolant ow (see Figure 1).
with a CobraCooler™ installed
with its integrated 12 foot cable.

female connector connects to the receptacle labeled “GROUND”.
Welding functions of the weldhead transfer through this connector.
face plate of the weldhead and maintain the weld joint alignment of the parts
to be welded. The collets are manufactured to correspond with the outside
two sides and one bottom. Two sets of collets are needed to weld two tubes
through the use of brass-tipped setscrews, referred to as plungers, in the
top Collet halves. These plungers not only make up the diameter difference
the grounding path between the weldhead and the tube or pipe to be welded.
the bored Collet surface.
Adjust the latching mechanism of the weldhead to ensure a tight, but not
Alternately adjust the plungers on one side of the weldhead until contact
At this point the tube should be rmly held in place. The tube should not
turn if attempting to rotate it by hand.

Appendix C gives the MK part numbers for pre-ground tungsten electrodes
the rotor while using a large arc gap.
welding procedure is established.
that should be de ned during procedure development.
the electrode is to be hand ground, use a dedicated diamond wheel. The
weld and tungsten inclusions in the weld bead.

All tungsten supplied by MK Products, Inc. is prepared using the latest
the tungsten set screw are visible in the top of the rotor. Loosen the tungsten
tighten the setscrew. Be sure to set the appropriate arc gap prior to welding.
welding equipment. Improper arc gap can cause arc strikes to occur to your
weld current level, but not so short as to ‘crash’ or touch the weld being
Arc Gap = (Wall Thickness x 0.5) + .010”
Any length of tungsten that is protruding out the back of the rotor will jam with
the meshing gears inside the weldhead. This will push the tungsten into the
weld being made and inevitably cause an ARC FAULT.
foreign matter, or a piece of tungsten electrode has fallen within the gear

150. Flow rates higher than 25 CFH can create
turbulence within the weldhead chamber and blow the arc about.
weldhead. Use a name-brand additive, (which does not contain reactive
And will Void the Warranty.
weldhead rotor speed and motor controller calibration. This calibration
the operator) for one revolution at each speed. The start and end of each
the weldhead. The rotation is clocked by the computer and, by process of
150 welding power-supply.
150 welding power-supply.

A report is generated showing the ‘measured’ time for each revolution of the
weldhead. The two readings are averaged together to give the ‘actual’ time
to convert the speed demanded by the procedure into a speed, which will
to calibrate the weldhead before each weld where environmental changes
When a new or repaired weldhead is received, a calibration should be run to
then be used to compare prior calibration reports to determine the condition
than .5 rpm off of the benchmark calibration then the weldhead should be

Tachometer: Gain error = -4.1% / Zero error = 0.13 RPM
ACL, however; it does show some very important information. It shows both
the MOTOR and TACH gain values. The calibration and adjustment is still the
to manipulate parts within the weldhead, which requires the use of a

When longer weldhead cables are needed, a weldhead extension cable
150: welding leads, gas, coolant supply and return and control
A set of Collets is de ned as 3 each 120° segments for each side of the
weldhead. Typically, 2 sets are required per each weldhead (See Appendix A
Weld uniformity depends on the accuracy of the position of the rotor during
welding. Rotor rotation should be circular in motion in a plane at right angles
to the tube and concentric with the center of the tube to be welded. Any
An electrical measurement should be made to determine continuity from the
to the jaws on the weldhead.
A measurement should also be made to verify that no conductivity
A visual inspection should be made to determine the condition of the
weldhead and the cable assembly. If there are damaged or worn items, the
weldhead should be returned for factory service.

Arc Start Troubleshooting
your Side Plate Clamp or Collets.
around the tungsten (reference Figure 3).
tungsten can cause poor arc starts and tungsten inclusions.
Avoid any tooling that might have sharp edges or points or this will cause
the smaller the tube in a given size weldhead; the longer the pre-purge
with a ne abrasive pad or cover it with appropriate insulating tape.
when the ‘Home’ switch is pressed; the Reed Switch is most likely defective.
weldhead must be returned to the factory for any

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Appendix B Locating Mandrels
Appendix C Pre-Ground Tungsten Electrodes

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Appendix A Collets and Jaws
Description Part Number Description Part Number
Appendix B Locating Mandrels
Description Part Number
Appendix C Pre-Ground Tungsten Electrodes

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- MK Products,Inc.,Irvine,California
warrants that all new and unused equipment furnished by MK
from defect in workmanship or material.
with respect to the quality of any goods, the exclusive remedies
therefore shall be at MK Products’ option:
where authorized in writing by MK Products, the reasonable
payment of or credit for the purchase price (less reasonable
warranty claim procedures to be followed.
As a matter of general policy only, MK Products may honor
following periods from the date of delivery of equipment
A copy of the invoice showing the date of sale must accompany
All equipment returned to MK Products for service must be
ANY EXPRESS WARRANTY NOT PROVIDED HEREIN AND
ANY IMPLIED WARRANTY, GUARANTY, OR REPRESENTA-
ABILITY OR OF FITNESS FOR PARTICULAR PURPOSE,
WITH RESPECT TO ANY AND ALL EQUIPMENT FURNISHED
WRITING, MK PRODUCTS ARE INTENDED FOR ULTIMATE