2013: MIG SPRAY TRANSFER: Thanks to aggressive weld equipment
salesmanship and lets face it, too common weld management -
engineering lack of best weld practices and process control expertise, during the last 25 years,
the biggest selling MIG welding power
source for for both manual - robot "carbon and stainless" steels welds has been a
pulsed MIG unit.
The above statement is really ironic, as in this time period the pulsed MIG equipment did not work the way it was
intended, and the over prices, erratic, pulsed MIG equipment when used on steel welds, provided
more neagtive weld attributes than real world weld benefits.
Most of the companies using pulsed MIG to manual and robot weld steel
parts > 3 mm, would be better served, if they had
used the more stable, consistent energy, traditional "spray
transfer mode". One of the prime reasons weld equipment manufacturers don't promote the benefits of the spray mode over pulsed MIG, is that spray transfer is available from the lowest cost, ($2000 - $3000) most durable,
traditional CV MIG equipment. This
statement was true 25 yeasr ago and it's still weld reality in
Understanding weld transfer modes is the first
before purchasing a MIG power source.
Few manufacturing mangers or engineers take responsibility for weld process
The sad reality in the welding industry is
have to look far to find someone in welding management that is not qualified for their position.
PROCESS IGNORANCE: In the weld industry, MIG weld best practices
and process control ignorance and confusion
is the norm and the typical, global weld shop reliance on inexperienced sales advice is
indication of a confused industry.
BELLS AND WHISTLES: In this industral enviroment, it's easy for MIG weld equipment manufacturers to sell weld
equipment that has useless bells and whistles which can dramatically increase the price of the MIG equipment.
PLAY AROUND INDUSTRY: For more than
five decades, the majority of global, MIG weld personnel
have "played around" with the two simple controls on that conventional CV MIG equipment. The play around personnel will be the individuals that the confused management turn to when that sophisticated new pulsed MIG power source is being demonstrated by the Lincoln - ESAB or Miller rep.
SALES RELIANCE: Experienced weld process control
individuals have for decades been in short supply, it's
therefore understandable that many weld shops became
dependent on the local weld sales-rep or the equipment manufacturer's rep for weld advice, even though this individual might have a degree in the arts or english, and rarely will have
had weld supervision or weld management experience.
LACK OF MANAGEMENT WELD EQUIPMENT - PROCESS OWNERSHIP: It's difficult to evolve in engineering and manufacturing when those responsible lack expertise and ownership with the equipment and processes that are critical to their organization.
TIG welding is still used for pipe welding, yet the TIP TIG process (www.tiptigusa.com) which is easier to use, always provides superior quality and makes the welds for a third of the costs, has been available for many years.
Many weld shops today will use SMAW electrodes, because they lack the confidence to select the forty year old flux cored process.
In most weld shops you will not be able to find anyone that can tell you the real cost of a weld.
In an industry that does not like change, someone needs to sing out, "come gather round managers, engineers, technicians, supervisors and welders where ever you roam, for the times they are a changing".
However when it comes to the 50 year old MIG spray transfer mode weld shops may want to be wary of the so called evolution of MIG, a process called pulsed MIG.
For many decades, the traditional MIG spray
transfer mode has been a work horse for manufacturing
companies and weld shops that rarely understood what spray transfer was.
When I wrote this in 2005, the weld supervision in the auto / truck
frame plants shown below, were happy to see the MIG weld
sparks flying, yet this too common pathetic fire works
display when welding, is nothing more than an indication of weld transfer mode and weld voltage
issues that result in extensive weld quality, weld clean up, and
weld productivity issues.
What does a manager or supervisor see
they walk past these MIG truck frame welders?
The fire works displays with these manual MIG welders making
is common. It's also an indication that the weld parameters
not correct, the weld quality will be poor and there is no weld management...
Understanding the optimum weld process fundamentals, best weld practices and weld process controls that can influence weld speed and weld fusion, does anyone care?
If MIG spray and
pulsed MIG spray transfer were two recent weld
an evaluation of both weld processes
by qualified persons would reveal some interesting weld
An examination of the influence of both MIG spray transfer
and pulsed MIG welds on steel parts over 1/8 (3mm) would reveal the;
[a] arc physics - weld plasma energy - weld transfer consistency - weld dymanics,
[b] weld parameter consistency,
[d] weld porosity content,
of the process for stable weld transfer with high speed welds.
reveal that the regular MIG spray transfer mode
typically provides superior weld results than pulsed MIG.
A message you won't hear from the companies
who manufacturer your weld equipment:
Irrespective of the fact
that MIG welding power source manufacturers and their
distributors achieve much greater profits from their $6000 to
$13,000 electronic pulsed MIG equipment,
traditional 300 to 450 amp, $2000 to $3000 CV MIG equipment
is still the ideal tool for most carbon and stainless steel
applications and especially on steel parts >
A common MIG CV power source and wire feeder package like
this Miller unit,
will sell in the USA for $2500 to $4000.
From a durability perspective, a CV power source like this should
readily outlast the pulsed power source by at least 10 years. Also the traditional CV power source
will not need an electronics engineer to make
repairs when required.
For those of you that have wasted your dollars on sophisticated pulsed MIG equipment for steel welds, don't get pissed of at the messenger, get pissed off at the salesman who made the decision for you, then get pissed off at the weld decision makers in your organization who lacked the process expertise necessary to make a weld equipment decision
If you have
no sense of humor, you
in the wrong industry. A sad Ed joke.
It's completely illogical to me, that the North
American weld industry while trying to compete with lower global labor
costs, has for decades had a majority of weld managers, supervisors and engineers who ignored or have been ignorant of the fundamental factors that
control MIG and flux cored weld quality and costs. Instead of understanding and reducing weld costs, these managers have been falling over themselves
to pay a premium price for poor
performing, over priced pulsed MIG weld equipment or unnecessary costly weld consumables.
Pulsed MIG and Spray Transfer Awareness: Pulsed MIG equipment
when purchased for welding carbon steels > 3 mm, can in
contrast to regular lower cost MIG equipment provide the
[a] Pulsed equipment is typically much less durable than
regular CV equipment, and it's often impossible for the
maintenance department to make repairs to the pulsed power
source. Thanks to this fact, many companies will waste $6,000
to $13,000 and purchase an extra pulsed MIG unit as a spare for
the weld shop or for the robot cell.
[b] If your weld personnel played around with the two control regular MIG equipment, why would they have the expertise to control and optimize the pulsed equipment with it's many bells and
whistles and process - program choices. The reality is the purchase of the pulsed MIG equipment simply adds to
the general weld process confusion already in the weld shop.
[c] Weld transfer modes are suited to specific applications. Pulsed equipment is often
used by weld personnel who don't have a clue about weld
transfer mode or the weld current compatibility with the metal and part
thickness welded. Also few weld personnel understand the relationship between wire feed - volt settings, the weld fusion and
weld deposition rates they could daily attain. With the
pulsed MIG equipment parameter focus often on the pulsed weld current
rather than on the wire feed settings, you can assume that the
majority of pulsed MIG welders will not be aware they may be
 welds with less than optimum weld fusion profiles,
 welds at lower weld deposition rates than that possible with spray transfer,
 automated welds with lower weld speeds than that which can be
regular spray transfer.
[d] The pulsed process which shifts between a high peak and low back ground
weld current, can on carbon steel and stainless
applications > 3 mm produce welds with inconsistent weld
fusion and welds that freeze to quickly causing porosity.
Extensive data on pulsed MIG is available in
the MIG pulsed,
MIG short circuit and MIG equipment sections.
< 2008: It's not just the
costly Japanese and European pulsed MIG weld equipment that
North American weld shops should be concerned about. If
during the last decade your company purchased Miller, ESAB
and Lincoln "pulsed" MIG equipment made in the USA, to weld
their carbon and low alloy steel applications, they wasted
thousands of dollars on unstable weld equipment that provided
minimal weld quality or production benefits.
For those that doubt my words, it would take me less than 60
minutes at any facility to prove this statement. By the way
you could purchase one of my weld process control books, walk
over to that traditional MIG power source, set my weld data,
pull down your weld shield and make a believer of yourself.
A few of Ed's weld process optimization projects:
FORD F 150 FRAMES -
VOLVO CABS - CORVETTE FRAMES -
HARLEY FRAMES - NEW BEETLE SEATS
ED ALSO ESTABLISHED
THE ROBOT WELDS FOR THE
WORLD'S LARGEST CATERPILLAR TRUCKS.
one day, the umbilical cord between
shops and the weld sales reps will be broken.
Come on you chicklets miglets , we have to follow
after all he is the "sales rep".
Does the following sound familiar?
Hang on Fred, I need some time to play around with the weld parameters.
Hey Joe, those weld issues are being caused by the gas mix.The gas guy will be here next week with a new three part gas mix.
Mike, why change the way we weld? after all this is the way we have always done it.
To correctly evaluate the pulsed
mode versus short circuit or spray transfer, a weld decision
maker should first be aware of the real world arc and weld
differences between the traditional spray transfer, short
circuit, globular transfer and pulsed mode.
Spray transfer is an
"open arc" mode of weld transfer which requires specific weld
parameters along with argon or argon mix.
In the spray transfer parameter range, the
spray arc weld will produce a combination of weld stream and
small weld droplets. The consistent energy spray transfer
molten metal cascades axially through the ionized, white colored, bell shaped, open arc plasma.
Note. The "medium" size weld droplets in the video shown,
are transferring from an 0.045 (1.2mm) steel weld wire. The
size of the weld droplets indicates that the weld transfer is
in the transition parameter zone that occurs with argon
mixes. This transition zone is found between the globular and spray
mode. As the spray weld current is increased, the weld drops in the
video that look like pulsed weld droplets will decrease in size
and change into a continuous weld stream. Depending on the
MIG gas mix used, the spray transition weld current with the
0.045 (1.2 mm) steel wire diameter will be approximately 250 - 255
amps. Wire feed 12 o'clock, (fifth turn, 5 x 70 = 350 inch/min) .
Note: For those who want an optimum pulsed MIG Start Point for any steel weld applications > 3 mm, you would set the 0.045 wire at the spray transition start. This logic applies to any wire size.
If the MIG spray wire feed (weld
current) is increased above the short circuit and globular to the
spray transition current, the higher magnetic forces
that result from the increased weld current will
influence the profile of the hot wire tip. The
increased weld current, (increased magnetic field)
will pinch the MIG molten wire tip to a fine point
resulting in smaller droplets that change to a stream of weld metal with droplets.
Robots and downtime in the Auto - Truck Industry.
Globular MIG Weld Scourge:
MANY WELD AND ROBOT ISSUES ARE CAUSED IN THE
AUTOMOTIVE INDUSTRY FROM THE USE OF OVER SIZE MIG WIRES. WHEN THE WELD WIRE SELECTED IS TOO LARGE, THE SPRAY TRANSITION CURRENT REQUIRED WILL TYPICALLY BE TOO MUCH HEAT FOR THE PART THICKNESS WHICH FORCES THE WELD PERSONNEL TO USE LOWER, ERRATIC GLOBULAR TRANSFE WELD SETTINGS.
MOST WELD PROBLEMS IN ROBOT CELLS ARE CAUSED BY
PROGRAMMERS AND UNQUALIFIED MAINTENACE PERSONNEL SETTING POOR WELD PARAMETERS, GLOBULAR TRANSFER IS A COMMON ISSUE WHICH INFLUENCES THE WELD QUALITY, WELD CLEANING AND ROBOT DOWN TIME
When the weld management (management maybe not the best word) selected an oversize
0.052 (1.4 mm) MIG wire for the Ford F150 frames, what the
unqualified management and egineers were not aware, was that the minimum spray weld
current required for the 0.052 wire was too hot for the gage
frame parts. Also the pulsed MIG parameters from the 0.052 wires and the costly
Lincoln Power Wave MIG power source were inconsistent. As the Lincoln Power Wave pulsed parameters created many weld issues with the large wire, the robot personnel put the data in the regular CV mode and the weld
parameters selected, resulted in globular transfer. On parts > 3 mm, globular
transfer can produce cold welds with lack of weld fusion and
extensive weld spatter.
Combine the common apathetic weld management practice of selecting
over size weld wires, with the common lack of weld best practices and process
control expertise on the shop floors and you are sure to have
extensive robot and weld issues.
MIG transfer produces medium to large weld
droplets that cascade across the open arc in an erratic transfer. The high energy
globular weld droplets will explode when in contact with both
the weld wire and work and these drops will result in excessive, difficult to
remove (the drops sometimes weld themselves to the parts) weld spatter.
Globular transfer is a prime cause of robot down time as the
explosive weld droplets often attach themselves to the contact tip often
restricting the weld wire as it exits the contact tip
As the large globular drops lack the weld energy and plasma
velocity of the conventional spray transfer, globular weld transfer not only produces excess weld
spatter, it's also a prime reason for lack of weld fusion.
There are six
primary causes of globular transfer and I cover this extensively in my Manual MIG and Robot Weld Process Control Training CD's
Weld process control expertise is not rocket science. A weld
simply has to read the right books.
My grandson is the one on the right.
Weld Process Expertise in the auto - truck
Industry, starts out with somone in mangagement having an interest in the subject. The weld magazine publishers in the
USA are well aware that the auto - truck company engineers that
are responsible for arc welding robots are least likely to subscribe to
their welding magazines. Even when the welding magazines are
free, it's rare to find one in an auto - truck manufacturing manager's or
engineer's office and even rarer to find one in the workers lunch rooms.
The general attitude
In the auto - truck industry is, why would anyone read
about weld processes, when all they have to do is pick up a phone and attain weld answers
(most incorrect) from a
weld salesman, or from a slightly biased Lincoln, ESAB or
E-Mail.from KD - P&F.
Ed, how are you doing? You would be interested to know that
by the end of the year I will have close to 100 robots
welding with 0.035 (1 mm) wire using spray transfer with no pulsing.
It only took 10 years Ed, but we are finally using the
recommendations you made in the 1990s. I now have
the top Honda guy in North America convinced that instead of
using pulsed MIG, the traditional spray mode is the way to go with many of
our MIG applications. In regards to your MIG process control
training, we now have two plants that are interested in
using your process control training resources.
Note from Ed: This E-mail was from a USA, Mid West tier one
company that produces parts for Honda and Toyota. Their plant
has over 200 hundred robots and Panasonic pulsed MIG equipment.
The Panasonic weld equipment and pulsed process was a
mandatory requirement of the Japanese parent company. For more than a
decade, the Panasonic pulsed MIG equipment generated hundreds
of pulsed MIG weld issues that dramatically impacted the
daily robot weld quality and production. With all the
problems, the engineers in Japan were reluctant to hear that
the traditional, more durable, lower cost, North American CV
equipment would provide solutions to the majority of their
welding issues. I guess even Japanese engineers with time,
(ten years) will eventually figure out the solution to simple welding
The inability to
establish Best Weld Practices and the general lack of
manufacturing weld process control expertise from
global manufacturing managers, engineers and robot technicians is
completely unacceptable when low cost, highly effective robot
/ manual weld process control training resources are
available. Click for Ed's CD, eight hour, Process Control
E-mail from TD.
07 / 2003.
Ed, We have used your training techniques at three of our
manufacturing plants that I have worked at over the past
number of years and thanks a million, they really WORK.
The other day I got into a heated discussion with one of our welders. He was welding mild steel, laying 3/16 to 1/4 inch fillets.
He was using 0.045. (1.2 mm) steel wire on 1/4" and 5/16"
(6-8 mm) plate. The gas mix, argon - 15 CO2. He was welding
with 28 - 30 volts, wire feed 250 ipm 190 - 220 amps. This
welder used this one setting for all position welds - even
vertical down. The arc sounded terrible and as you can guess,
he had nothing but spatter, and spent much time cleaning his
welds. I tried to help him out, but he more or less told me
to go back to the office where I belong. I was going to
tell him to switch to an 0.035 wire, starting at about 500
ipm, set the voltage to an initial setting of about 28 volts
- lay a bead, then adjust the voltage for the correct sound
of the arc - slight crackle. Who is right? If I'm wrong,
please let me know.
Thanks a bunch. TD.
TD. In the thickness range welded, the 0.045 wire is fine.
The wire feed setting however is set in the globular transfer
mode which will result in both poor penetration and lots of
spatter. If he wants to weld vertical down with the 0.045
wire he should be at the start point of spray, 350-370 ipm,
260 - 270 amps (just past 12 o'clock) with 24 to 26
Vertical down welds would be easier to control with the 0.035 (1 mm)
wire. For vertical down welds with the 0.035 wire, set the
wire setting at 500 ipm, (just past 2 o'clock) with 24 - 27
volts. For horizontal fillets with the 0.035 wire set 600
(3 to 4 o'clock) with 28 - 30 volts. The key to dealing with
this welder who lacks process expertise, is first take the gun from his hands, change the
weld settings and show the welder a superior weld. You could also
advice your apathetic management to provide the welders with what they really need, process training. Regards.
ROBOTS & WELD SPEEDS. Many companies who purchased pulsed MIG equipment for
their robot cells, may have had high robot weld speeds and
high weld production expectations. The majority of weld
decision makers who purchased the MIG equipment for the robot cells were under the impression that with the
new, sophisticated, pulsed MIG equipment, that their Multi - Wave Form, Pulse on Pulse, AC - DC, Fuzzy
Weezzy, Remote Wireless Controlled, $13000 MIG power source, that they can now 'weld faster"
with more production that that possible with a conventional MIG power source on applications > 3 mm.
The MIG weld
speed reality is this. The low cost MIG equipment that has delivered MIG spray
transfer since the 1950s has always provided the fastest most stable MIG weld
speed potential on carbon, low alloy and stainless steels
parts > 3 mm. Note in Australia using my MIG process control resources, companies are making spray welds in the 15 - 25 lb/hr range. Few weld shops in North America, when using MIG attain over 15 lb/hr.
When welding carbon and stainless steels under 1/8 (3 mm), if
you have the right pulsed MIG equipment, pulsed MIG can provide higher weld speeds than short circuit welds. Conventional spray is typically too
The following are a few MIG Spray Transfer weld
For those of you that believe the pulsed equipment is
depositing more weld or delivering faster automated weld
speeds, on applications > 4 mm, compare what you are
achieving with this weld reality.
With low cost, traditional,
durable CV MIG equipment, spray transfer when used on parts
> 4 mm, weld deposits in the range of 8 -
25 lb/hr are being utilized. On these applications, the pulsed MIG mode can not
deposit more weld metal than spray transfer. The typical, stable pulsed spray deposition range is 8 to 14 lbs/hr.
 Using conventional weld practices, the typical spray transfer "robot or automated, common, 1/4 (6 mm)
fillet welds" made on parts > 5 mm, are made at weld
travel speeds of 18 to 23 inch/min. On these parts pulsed
cannot provide faster weld speeds.
 When welding the common 3/16 (5 mm) fillet welds, the typical weld
deposition rates with an 0.045 (1.2mm) wire using spray
transfer will be 10 to 12 lbs/hr. The automated weld speeds
for this weld should be in the 40 to 60 inch/min range. With extended wire
stick outs, (information in Ed's "Management Engineers MIG"
book) I have
produced these 3/16 fillet spray welds at robot weld speeds up to 85 ipm.
On these parts, the pulsed process
will not provide faster weld speeds, however the pulsed mode
can if required provide lower weld heat (lower distortion) than that which results from spray.
One of the very few limited Pulsed MIG weld benefits: The pulsed mode when used and set correctly, on
steel applications less than 1/8 (<3 mm), can provide higher weld
deposition rates than short circuit or globular
transfer. As short circuit is a poor choice, pulsed MIG is also a logical choice for < 3 mm aluminum applications.
The first words my grandson said;
Weld Magazines and Weld Equipment - Consumables Bias: I have had 30 articles published in weld magazines. The weld magazines of the 1980s have little in common with those that are in place today. Today when you read
about weld process, consumable or equipment articles and recommendations in the North American weld
magazines, you will too often find a strong, marketing influenced bias in the article which adds to the never ending BS we find in too many weld shops.
The reality is as advertising revenues shrink annually, most weld and related magazines get the majority of their
advertising revenues from the companies that provide the
majority of their weld articles.
E-mail. Nov. 2004.
Hi Ed. It's Matt Finn. I spoke with you on the phone a couple
of weeks ago. Well contrary to the beliefs of my co-workers I
must say your concepts on GMAW were well worth trying. Your story
of reading weld literature articles and finding they are too often not factual, inspired me to do the same and in the last three years, all I have done and continue to do
is read from a variety of welding resources. In the past
few weeks, I have focused my study on the "hands-on" practical
aspect. It's amazing what you learn from having your nose in
the arc rather than observing from out side the robot
After reading your books and getting hands on experience, I
now fully understand how and why Globular transfer is not a
reliable mode of transfer, especially when utilizing it for
high travel speeds (50- 70ipm range). Tonight I was able to figure
out how you were able to achieve over 70 ipm when welding in
spray mode. I went snooping around the plant and found an old
style of diffuser that was shorter than our common ones. I
then took your advice from your Management Engineers book and
cut about a quarter inch off the end of a contact tip. With
having the tip well recessed in the nozzle, this allowed for
a longer than normal wire stick out which decreased the weld
amperage but still maintained the weld current within the spray
The longer MIG wire stick out, permitted me to run higher
WFS (higher deposition rates) without the extra amperage that
would cause unwanted weld heat defects such as burn through or undercut. The weld spatter that
resulted with the longer WSO was minimal and the spatter was easy to remove. Also
the recessed tip and diffuser were spotless. After trying your ideas on attaining high deposition high speed welds in your "Management
Engineers MIG book"
it now makes sense. Thanks Ed for your extensive web site and your weld
Matt Finn. USA.
for his opinion on spray transfer
versus pulsed MIG,
A guy called Albert might have said the following.
"Constant weld energy attainable from CV spray transfer
is a logical requirement for constant weld fusion".
The three most important aspects of any weld, are the size, the weld fusion and quality attained.
 With more than 90% of all MIG welds there is no evaluation of the weld fusion attained.
Every weld shop that MIG welds should be aware that the primary weld concern with most steel and stainless welds over 3mm is
to attain sufficient weld fusion in a consistent manner.
 In contrast, a primary MIG concern with most steels under 2 mm is avoid
weld burn through and distortion.
PULSED MIG AND HOT CRACKS: A common concern you will find with high deposition
rate pulsed welds. When pulsed is used in the high, "stable
spray transfer wire feed range", the pulsed MIG arc is influenced by
the high pulsed Hz and high peak current required. This combination often provides a highly
agitated pulsed arc that results in a narrow, high velocity
plasma. This high velocity pulsed plasma can provide a digging effect
resulting in crater problems and narrow weld penetration
profiles that can lead to hot, center weld cracking.
Ed made the following
manual spray transfer weld with a $250 traditional MIG CV power source using an 0.045 (1.2 mm) E70S-3
MIG wire, set at 450 ipm. (1 - 2 o'clock), approx. 12.5 lb/hr.
These deposition rates are extended with increased WSO.
What's that $6000 - $12000 Pulsed MIG power
source going to achieve?
attain the open arc spray transfer for carbon steel or common
stainless steels, an argon mix is required along with a
specific minimum amount of weld current (> 200 amps 035. > 255 amps 045), the wire feed rate and
the voltage for each electrode wire diameter selected. The
resulting spray weld stream is protected from the atmosphere by the
spray plasma, (the ionized, white, bell shaped cloud).
The spray transfer arc plasma not only conducts the weld
current, the plasma with argon mixes also shrouds the
electrode wire tip. In contrast, when using straight CO2, the
arc plasma occurs "under the weld droplet being formed. This plasma supports the weld drop as it forms and grows till eventually it
drops off the wire tip in an erratic manner. The CO2
plasma is the reason you
cannot get spray transfer from straight CO2. It's also the
reason the CO2 content is limited to approx. 20% in argon mixes. See MIG gas mixes if you want
to cut through gas salesmanship and read more practical gas
When welding bombs, you would think some
manager or engineer
know the difference
between a MIG short circuit and spray transfer weld.
The real weapons of mass destruction is often the
apathy thats found in the engineering department that make weapons.
Many years ago, a major
European military contractor wanted to me to optimize
the bomb lug welds that attached the cylinder shaped bombs to the underside of the fighter
planes. The management was concerned about what would happen to them if a bomb should fall off the plane and kill someone.
The weld focus was to optimize the weld fusion attained
between the thick bomb lugs and the heavy wall (1/2 - 1 inch ) bomb casings. The weld process improvement was necessary as the majority of the
bomb lug welds being produced revealed welds (which had been made for years) that had got so bad, that most of th welds had more than 50% lack of fusion.
The first thing I found at the bomb plant, was their was no weld management, just a bunch of military type engineers that thought they were managing a parade ground. The welders who did not know better were utilizing poor MIG weld practices and using both the MIG short circuit and globular weld transfer modes. Using these two low energy MIG weld transfer modes that were more suited to 14 gage welds than the 1/2 to 1 inch parts welded, it was simply impossible to get the weld fusion desired for the lugs.
To rectify this companies weld issues, I had a choice between the use of pulsed MIG or spray, (they had recently purchased new pulsed MIG equipment).
After I produced the pulsed and spray welds at the same wire feed rates to maintain production. For both processes I set optimum weld parameters. The weld macro weld tests clearly indicated that the spray transfer mode had to be the first choice to
provide the consistent weld fusion necessary. By the way I knew this would be the result before i welded. I simply did the two weld mode tests to show the engineers that the solution to their weld problems was always with the old equipment thay had and they did not need to take the sales reps advice and purchase the pulsed MIG equipment. After the weld tests were done I provided training for both the workers and managers and that was that.
Power point from Ed's Robot MIG
Controls Training Program
More SPRAY Fundamentals.
The argon mix plasma that envelops the MIG wire tip,
allows the weld droplets (transition) or stream to
transfer axially, in a stable manner. If more than 20% CO2 is utilized the plasma is lowered under the droplets, supporting the drops till they grow and erratically transfer when they succumb to gravity
Note: In this video shot the spray transfer is in the
transition zone found between short circuit and spray.
This zone results is a distinct controlled weld drop
that looks very like a pulsed weld. The spray plasma
also enables stable transfer of the electrons as they
transfer from the negative work, weld cathode spot
locations, to the positive anode areas located on the
electrode wire tip.
While the negative electrons are driven
upwards to the positive wire tip by the weld voltage,
the positive larger gas molecules are driven downwards
to the negative work. The electrons on there way to
the wire tip collide with the larger mass, gas
molecules. The electron and gas molecule collision
causes the gas molecules to split (ionization) adding more free
electrons and protons in the arc plasma, this increases
the plasma ionization energy. The electron and gas
molecule collision increase the MIG plasma arc
conductivity and the energy.
Spray transfer and effects of Mill Scale:
The mill scale on
that hot rolled plate surface to be MIG welded may be a poor
electrical conductor causing electron reduction and arc instability. The electron
conductivity of spray transfer is influenced by both the mill
scale thickness and mill scale composition.
Mill scale acts
as an insulator which can impede the electron flow from the
cathode spots on the weld surface as they travel to melt the MIG
wire tip. As mill scale increases the weld energy is reduced and to sustain the open arc, the MIG weld
voltage has to be increased. Mill scale melts at a higher temperature than the base metal and typically the welds become more
If you make a spray transfer weld on carbon steel without mill
scale, and then without changing the weld voltage, make a spray
weld on a part with mill scale, the welder would note
the arc distance from the wire tip to the weld has reduced.
The arc length reduction is a result of a decrease in
electron conductivity, less electrons = less energy to melt
tip of MIG wire and the wire gets closer to the weld. The
shorter arc length often results in the MIG wire running into
the weld, displacing the weld causing weld spatter. To reduce
the weld spatter would require that the welder increase the
weld voltage to increase the arc length. As we don't teach
welders this simple fundamental fact we end up each day
spending millions removing excess weld spatter.
Even with the correct voltage, the higher melting temperature mill scale can affect the weld fusion
- porosity potential and frequently these welds will solidify in a convex
shape with a roll over at a fillet weld toe. The influence of
mill scale and the process requirements to compensate for the
sluggish welds and spatter control, is another reason why
weld personnel would benefit from my weld process control
The influence of the MIG arc characteristics on mill scale.
An intense, consistent high
energy arc as found with a spray transfer weld is more beneficial than pulsed MIG with it's fluctuating peak to back ground current when dealing with mill scale issues.
In contrast to pulsed MIG, the CV spray arc will;
[a] assist in maintaining consistent electron flow adding to arc
[b] assist in the removal of surface
[c] provide superior wetting for a sluggish
[d] provide consistent weld fusion.
[e] provide less weld porosity
The sluggish MIG
welds made on heavy mill-scale parts will often result with
unacceptable or marginal side wall weld fusion.
In contrast to pulsed MIG, when using optimum spray transfer weld
parameters with argon - 15 to 20% CO2, the spray plasma arc
intensity is much more "constant" and the average energy
generated is typically greater than that attained from the
pulsed welds made in their optimum parameter range.
pulsed MIG, the plasma is influenced by the peak to low
background current variations and the weld current and
voltage fluctuations which are common from the electronic
pulsed MIG equipment. Also pulsed MIG often utilizes low energy gas mixes like argon oxygen or argon 5 - 10%
CO2 which also decrease the weld energy.
and Weld Current Stability?
2004: While testing Japanese and Americam pulsed MIG equipment, we had this oscilloscope graph
made of a carbon steel "pulsed MIG weld" set at optimum weld
parameters. As the graph below indicates, when using one of the most costly,
popular and sophisticated pulsed MIG power sources sold in
the USA, that weld current and voltage instability is the
In contrast, the graph below is regular
the same time
CV MIG power source that cost 1/3 the price of the pulsed power source.
The influence of the MIG plasma shape and intensity:
Spray transfer produces a bell shaped plasma. The wider the
plasma in the cathode spots area, (the work - weld surface),
the greater the weld area that benefits from the MIG plasma
surface cleaning attributes and the greater the arc stability.
In contrast to spray, the pulsed process typically provides a narrower
plasma that fluctuates with the changes from peak to back
ground current. As you increase the pulsed welding parameters
to traditional high spray transfer wire feed
levels, when welding steels > 5mm, the pulsed plasma zone
which is influenced by the "high frequency, high peak pulsed weld
current" can become intense. Typically the excess
high peak current can result in an intense pulsed plasma
that's conical and narrow in shape. The resulting narrow intense
plasma configuration can cause an arc digging effect that may
result in deep narrow weld penetration. These pulsed MIG welds may
[a] narrow weld beads that depending on the application can produce (hot center weld
[b] excess undercut,
[c] frequent crater cracks.
The MIG spray mode allows a shorter arc length than pulsed MIG:
The shorter arc length (wire tip to weld surface distance) allowed by spray transfer can provide a
highly localized, intense plasma configuration that is very
beneficial for the weld stream transfer on robot high speed steel welds, and also beneficial on high deposition
welds, large size welds or when welding plate with surface contaminates such as
< 2005: How many of you have used pulsed MIG for high speed
welds >30 ipm, and found the weld transfer was inconsistent and the welds were skipped. Just about
every auto - truck wheel or torque converter manufacturer found this
problem with their costly pulsed MIG equipment, yet these
manufactures continued to utilize and purchase the pulsed weld equipment that caused the issues.
The Pulsed MIG mode requires a longer arc length: For the uninterrupted formation
and transfer of a pulsed weld drops across the open arc, the pulsed MIG mode requires a longer arc length than traditional spray transfer. The bottom
line, depending on the weld surfaces the weld settings and pulsed equipment utilized, the pulsed
mode on many welds can be arc length (voltage) sensitive. This sensitivity upsets the pulsed weld droplet transfer causing arc instability (often evident in the arc sound produced). In contrast, the
traditional spray mode in which the metal transfers in a
stream can utilize much shorter arc lengths and the
continuous weld stream is hardly affected by minor arc length
variations. The arc length sensitivity is an important point as it
[a] Shorter, less sensitive arc lengths allowable with spray
transfer improve arc stability when welding at a high
[b] Shorter less sensitive arc lengths allows longer wire
stick outs which reduces wire burn backs to the contact tip.
[c] Shorter less sensitive arc lengths are beneficial when
welding on mill scale or coated metals.
MIG Gas influence on Mill
When spray transfer welding on troublesome mill scale
applications, a high energy MIG gas mix such as argon with 15
to 20% CO2 is recommended. The 15 to 20% CO2 gas mix in
contrast to a lower CO2 mix, or argon oxygen mix, enables
higher weld voltage to be used and promotes higher energy at the cathode
locations on the plate or weld surface.
Note While at AGA, Ed and his friend John Lowery, were the team that introduced the gas mix argon - 20% CO2 to the USA. In the following years many of the weld distributors who were making this gas mix were putting too much CO2 in the cylinders. With this in mind Ed lowered the CO2 content and then introduced
to the North America the argon - 15% CO2 gas mix.
What makes CO2 gas unique? The CO2 plasma provides unique
"gas dissociation properties". In the MIG arc. The CO2
molecules break down from CO2 to CO and O2. When these molecules get close to the
cooler weld surface the CO - O2 molecules form back to CO2. This gas dissociation,
"molecular change" adds energy to the weld.
In contrast to argon with 5 - 10% CO2, and tri mixes containing argon - CO2 - oxygen, the 15 - 20% CO2 typically requires 1 to 2 extra weld volts to sustain the arc. The extra voltage and CO2 arc
dissociation properties improves the electron flow,
improves the arc stability and enables additional weld energy for improved weld fusion and lower porosity.
For those companies that use argon oxygen mixes, or the
heavily marketed, useless three part mixes containing argon -
CO2 - oxygen on carbon steel applications that have mill
scale, (applications >3/16), they should realize they are
jeopardizing the weld fusion potential and increasing weld
The oxygen and low CO2 in many argon
tri-mixes, results in a spray transfer plasma in which low to
medium weld energy is generated in the outer periphery of the
plasma. This results in finger or nipple shape weld profile. As the
narrow finger weld solidifies rapidly this increases the
opportunity for weld porosity to form especially in the
finger shaped weld root. It's very common for this defect to show up
in ultrasonic evaluation or with x-rays on fillet welds on parts
In contrast to what some weld gas
sales rep may tell you, two or three component gas mixes
containing oxygen can result in welds with greater potential
[a] weld porosity,
[b] welds with lower weld energy, resulting in inferior weld
[c] less gas in the cylinders than that attained with argon
15 - 20% CO2 mixes.
extensive weld gas data see my weld gas section, or better still,
invest a few dollars on yourself and purchase one of my
welding books. My " Management
Engineers Guide to MIG" has over 600 pages on how to
control all MIG and flux cored welds.
Note Ed was a key writer of the USA AWS "MIG Gas Specifications".
E Mail. July 05.
Ed. It looks like we are just starting out on a new
Chrysler project welding a galvannealed product. Galvanneal
NS 6000 D series 44a. According to the Chrysler weld specification, we
with MIG we would be allowed to use a solid carbon steel ER 70S-3 MIG
wire, however they require a 75 argon / 25 CO2 gas mixture for
this application. I think Chrysler takes the cake on this MIG gas selection.
By the way if our engineers had selected galvanized material,
according to the Chrysler spec we would have been forced into
using the terrible Lincoln self shielded FCAW process.....Is the
Chrysler weld engineer from this planet? What I also don't
understand is the fact that they are specifying a coated
material, and then we are still required to e-coat the part.
I wonder what the reasoning is behind double coating the
cradles.....I'm sure they don't even know.
Regards GR. Tier One Supplier.
There is no rationalization for most of the weld logic
that comes from the mouth of the Corporate weld engineer at Chrysler. Their chief
welding engineer has for more than a decade been in the wrong
profession. The choice of the 75-25 CO2 gas restricts the use
of spray transfer that could be used on robot welded parts over 0.080. The 75/25 gas
will instead be the cause of weld spatter or weld burn through. As
for the use of the self shielded wires, no one knows why the
Chrysler corporate engineer still insists on the world's
worst electrodes for coated materials. The weld engineer made this decision for Chrysler its cost them millions in weld rework and lost production and he has to much of an ego to admit his recommendations were wrong. As for the double
coating, it makes no sense. What would make sense is this industry could coat
many (not all) parts after welding. All those involved with welding are aware that irrespective of the coating type,
the weld destroys the coating in the weld area, therfore from a corrosion perspective the weld areas are the wekest links. As I have
said on numerous occasions on this site don't look for weld
logic and weld reality when dealing with the Chrysler coporation.
Want to know how to reduce weld cracks or arc
Minimum Spray Transfer weld current
with argon > 10% CO2 Mixes.
Many welders and robot programmers are not aware of the
minimum weld current or minimum wire feed rates necessary to
attain optimum spray transfer. Its therefore not surprising
to frequently find welders or robots welding with globular
transfer and creating a weld spatter mess.
When welding carbon steels with the 0.035 (1 mm) wire, and
a 15 to 20 CO2 mix, to achieve spray transfer, a minimum weld
current of > 185 amps is desired.
For the 0.045 (1.2mm) wire and the 15 to 20 CO2 mix. To
achieve spray transfer, a weld current approximately > 255
amps is desired.
These minimum spray transfer weld current settings are
reduced with lower CO2 mixes,
or when those useless two or three component argon mixes containing oxygen mixes are
There is an optimum MIG Wire Diameter
for every application thickness.
As I have mentioned 600 times, the auto / truck industry is one
industry that for decades has been notorious in it's
selection of unsuited MIG and flux cored electrode diameters
for welding steel applications < 6mm.
companies understand the weld wire, weld mode, weld current,
weld size, weld travel rate
and part thickness relationships. For those individuals that want to proffesionally manage the MIG and FCA weld processes, this is an
extensive part of my books and weld process control training
2013: Did you ever consider why, after at least four to five decades of
making MIG welding equipment and welding consumables, that
Lincoln, ESAB, (Linde), Miller or Hobart did not put practical
MIG weld parameter information on their MIG wire packages or
along side the relevant MIG wire feed or power source
I believe the reasons the MIG welding
electrode wire manufacturers never provided their welding
customers with practical, cost effective MIG or flux cored
welding data on the wire boxes, is because they did not employ management or engineers that had figured out
the simple relationships that exist between the few required wire feed
and voltage settings necessary for the majority of all the
common global MIG and flux cored applications. To overcome their focus on weld process controls I developed the "Weld Clock Method".
In the weld equipment and consumable distributor industry,
sales and real world data were often far apart. The
incredible lack of MIG and FCA weld process expertise that prevailed from the world's largest weld consumable manufacturers and thousands of distributors is
not that unusual. As we all are aware just because you make
something does not necessarily mean you are an expert in it's
use. The sad issue today for the self taught global weld
industry, after 50 years of weld misinformation, too many
weld shop still rely on these same companies for weld
Note: In the 1980s in a marketing program I set up at AGA in
Cleveland. I introduced MIG weld wires which were enclosed in boxes in which I had printed all the short circuit and spray
weld settings required for any applications with the 0.035 and 0.045 wires. With Airgas and Liquid Carbonic, I created simple two part SteelMiX and StainMix gas mixes, and then I put the labels on the cylinders that again provided all the possible optimum MIG settings.
Note: Ed got the GM management - engineers to stop using the nasty
self shielded flux cored weld wires for the CORVETTE
body welds, and then trained the GM workers on how to use the MIG process on the same application. Keep in mind, this was after MIG had been available for four decades. This shows that in the automotive industry, you can always hope that sanity will prevail. By the way, I would like
to thank the Corvette racing team for making me there
unpaid MIG weld consultant..
The MIG process celebrates 50 years as
being the world's most utilized weld joining process yet, how
many of you have watched weld equipment and consumable reps
"play with the weld parameter controls" during a
demonstration of MIG equipment, weld wires, gas mixes or those E71T-1 flux cored consumables?
For an experience you may not enjoy. Next time you visit a
Fabtech or AWS weld show, ask the Lincoln - Miller - ESAB -
Panasonic rep the following technical question. Look for
someone demonstrating pulsed MIG, then ask them to do a
6 mm vertical up, carbon steel or stainless fillet weld on > 1/4
(6mm) plate. After the weld, look the rep in the eye and ask
how his pulsed wire feed rate compares weld deposition wise
with an 0.045 (1.2 mm) E71T-1 wire set at a feed rate of 400
in./min. The weld you view and the answers you receive to this fundamental simple
weld question will show you how little or how much is known
by the so called weld equipment or consumable experts.
The sales reps promoting pulsed weld equipment
at the AWS or Fabtech trade shows may extol the virtues of
their weld equipment benefits, however, the bottom line is
those benefits may dwindle quickly when you take a real look
at the inconsistent arc characteristics and then
provide a realistic comparison of their process or equipment
against other processes, mode of weld transfers, equipment
Before weld personnel provide an opinion on a welding
process or weld consumable, they should have all the
facts on the processes and consumables that compete
with their process or consumables. And of course if
they were a true professional they would then provide
an answer without product or process bias.
established the robot welds for Harley bike
frames, he resisted the use of the pulsed mode and used spray
transfer. Ed set 3 simple weld schedules for the more than 50
welds required on the frames.
Note on Harley lack of management: At the main Harley Bike plant, I
sat in on a meeting in which two weld engineers and nine
robot personnel discussed for more than two hours a robot MIG
weld spatter problem on a bike gas tank. At the end of two
hours, the problem was unresolved. Thanks to the Harley "hands
off" management approach, I was not allowed to speak at this
meeting. The management were afraid I would upset the Harley sensitive workers. For me, that meeting was a sad engineering situation. This American company with it's global brand reputaion indicated that it's combined mangement and engineering resources could not resolve a simple weld voltage issue that should have
taken two minutes to resolve.
How many global production man hours are lost daily with inexperienced weld team meetings having discussions on robot weld issues which with a little weld process expertise would take a few minutes to resolve? Ed Craig. 1985.
If you want a quick
evaluation of the weld process expertise in your shop, ask three of
your welders or the weld shop supervisor to tell you the
0.045 (1.2mm) wire feed position in which the start point
occurs for spray transfer. You may be surprised at the
diverse incorrect answers provided for the world's most
popular wire size and the world's most utilized weld transfer
If you think your weld personnel
fully understand the weld process they make a living from,
why not give them my MIG weld process control quiz?
"Play Around". No managers or engineers should allow these two words to be used for any manufacturing process that is critical for an organization.
The good news
is the common lack of MIG and flux cored weld process
expertise can be quickly eradicated in any weld shop. First managers have to
put their focus on the root causes of their weld issues and
always remember that quality - productivity responsibility and product liability starts in the front
office, not on the factory floor.
HANDS OFF WELD MANAGERS AND ENGINEERS WONT MIND WHEN THE
PURCHASING MANAGER MAKES WELD PROCESS - CONSIMABLE DECISIONS.
When purchasing personnel make weld consumable or equipment decisions, the management supervisors & engineers should resign.
the weld manufacturing industry and especially common in the auto - truck industry, "purchasing managers" and other
inexperienced personnel are frequently involved in weld
consumable and weld equipment selection decisions.
Perhaps your company has a purchasing manager that found out that "bigger
weld wires cost less than smaller wires and therefore recommended the large wires which resulted in a
"weld wire cost savings".
When selecting the correct MIG wire diameter, the optimum
weld current compatibility of that wire with the part
thickness, the weld transfer mode and weld size are the prime
considerations for consumable selection. Selecting the
optimum MIG wire diameter requires MIG weld process
expertise. For those companies that are utilizing wire
diameters that are too large, most of the welds produced with the over sized weld wires will be in the globular
mode the weld productivity, costs and weld repair consequences will be
It's a fact that more than 75% of the MIG and flux cored robot
applications welded in the North American auto and truck
plants, are using weld consumable sizes and types that are not
optimum for the welding applications.
To Ed Craig. Sept 2004.
Question: Ed. Our company is a US based, Japanese auto
parts manufacturer. We use Japanese robots to MIG weld 1
to weld 3mm steel parts. We use the pulsed MIG
process, argon gas 10% CO2 mixes, and 0.045 weld wire. We use
Japanese MIG wires equivalent to AWS E70S-6. The manager
wants to reduce robot-welding costs. I am currently writing a
cost justification calling for a change to a MIG wire
manufactured in North America -- possibly an 0.035-in. wire.
Our company engineers, however, insist on sticking with the
imported Japanese MIG wire which costs approximately $0.50
more per pound than the equivalent USA MIG wires. These
engineers also inform me I cannot change the wire size or
type since the code states this wire is an essential weld
variable. Am I correct that according to most codes, as long
as both wires are E70S-6s, they are interchangeable and
therefore a none essential weld variable?
Essential weld variables are three words that
may carry some weight in an organization that welds within
the boundaries of codes such as API or ASME. However from a
common sense perspective these three words should never be used
within the boundaries of an automotive plant and especially in your plant.
First, irrespective of the codes or weld procedures in place,
as long as the plant uses argon mixes there will be no
negligible influence on steel weld mechanical properties,
whether the MIG wire is American or Japanese E70S-3 or
E70S-6. Both these MIG wires are qualified for argon mix use.
Second, if the company changes the wire size, it's logical to
redo the weld procedure.
Importing costly MIG wires into the USA a country that has the
world's largest MIG wire manufacturer makes as much sense as
exporting USA coal to Newcastle UK. Any US or Japanese
auto-manufacturing company that throws money out the window
by importing expensive Asian MIG weld wires needs a new plant
and engineering manager.
It makes little sense to be concerned about so-called
essential weld variables when the pulsed-equipment
manufacturers are making radical E –Prom changes to
their weld equipment every few months. Each new robot line
brought into your plant has pulsed equipment that may have
little in common with the pulsed-weld equipment purchased two
Weld procedures have little meaning when the weld
equipment used is either changing or inconsistent and lets face it the majority of robots sold do not have proper calibration between the robots, power sources and wire feeder. It also makes little sense to
worry about essential weld variables, when every day some
robot technician in your organization is probably making unqualified weld changes
to the robot data. And most important, why worry about essential weld variables
when the parts you produce will likely suffer from dimensional
issues that afftect the weld fit and weld gaps.
It's rare in auto - truck manufacturing plants that
strive for manufacturing autonomy to see effective weld
practices or effective robot weld process controls
implemented. It's even rarer to find engineers in this
industry who have in-depth weld process control expertise.
This of course leads to the weld consumable cost
discussions and distractions from the real weld issues.
To have an impact on a plant's weld costs forget about saving
pennies on consumables and start out with an evaluation of
the “weld deposition rate potential” and the
real-world weld efficiency of the robots. Evaluate the
robot's downtime and the robot weld rework generated. Compare these
numbers with the information attained in my
robot-weld-process-control book. Check out the high
weld-speed benefits of a 0.035 or 0.040 in. wire on parts
less than 0.080 in.
The engineers and managers who want you to use the Japanese weld wire
do so because they fear process change. My solution would be to
fire all the engineers and managers involved.
1998. The best MIG weld wire
for the auto and truck
industry is of course the one they rarely will use.
Weld Question: We weld carbon and stainless steel parts 3 to 5 mm. What's the best MIG electrode size for spray transfer robot applications?
Our key weld
Answer: Considering the weld current compatibility with
the part thickness and desired weld size, the following is a
logical choice of MIG wire size selection.
[a] Robot - Manual Spray welds on steel / stainless parts
3 - 5 mm. If available, the first choice MIG wire diameter would be the
0.040 (1.1mm) MIG electrode wire.
If the 0.040 wire is not available, use the 035 (1mm) wire.
Wires smaller than 0.045 provide superior small weld puddle
control and the spray current range of these wires is better
suited than 0.045 wires.
E-mail March 2007.
Ryan Good. Dana Corp.
Just thought I would drop you a line and let you know that in
the beginning of April, thanks to your advice, we will be
working on switching over the 5th Dana plant to an 0.040 MIG
wire and using the spray transfer mode instead of 0.052
globular mode we were getting with the Rapid Arc (Lincoln's
pulse MIG program). Thanks Ryan.
A reason the 0.045
(1.2mm) weld wire is an optimum choice with spray
transfer, for applications > 3/16, > 5mm is the "weld
current required and control of the weld fluidity".
This is a prime reason the 0.045 MIG wire is superior
to the higher current 0.052 and 0.062 (1.4 - 1.6mm)
The 0.045 wire also can
provide spray transfer at typical current of 250 - 380 amps. For the
0.052 and 0.062 wires to out perform the weld deposition
rate of the 045 wires, the larger wires would have to
use well over 400 amps, this higher weld current promotes
excess weld fluidity and is hard on both the weld
equipment and welder's skin.
When welds are produced
over 400 amps the resulting high weld heat and fluid
welds can cause undercut. The hot welds will also react
with the atmosphere and form oxides increasing weld
porosity potential, especially on multi-pass welds.
Also high weld current can promote grain growth and weaken the steel adjacent
the welds. The excess weld heat can also lead to hot cracks in the base metal
especially when welding high strength steels or highly restrained weld
High spray weld current > 400 amps can cause excess weld
fluidity creating a challenge for a manual welders, especially
when producing single pass horizontal fillet welds larger than a 1/4
A horizontal 5/16 (8 mm) fillet weld provides a manual welding
challenge. Maintaining weld puddle control, avoiding
undercut, and at the same time ensuring consistent side wall
weld fusion are three of the prime reasons the 5/16 (8 mm)
fillet weld is usually the maximum horizontal fillet weld
size allowed. This is also why robots should when possible
weld large fillets in the flat position.
When robot welding in the "flat positions"
rather than the horizontal position, and the parts are
>5/16 thick, an 0.052 (1.4mm) MIG wire is
beneficial and this wire will cost less than the 0.045.
Lets see, the electrode size
recommendations should provide an optimum spray transfer
current range which is compatible with the part thickness welded and allow control of the weld fluidity and oxidation.
This is an interesting approach to weld wire selection and
weld process control. Weld current compatibility with the
part thickness means the electrode selected can use the high
end of it's optimum operating parameters without concern for
an agitated arc plasma and a turbulent weld puddle. Using current compatible with the part thickness means no concern for over heated, oxidized
welds or weld burn through. The welding parameters
will allow high wire feed rates resulting in optimum weld
deposition rates and maximum weld travel rates for the weld
Weld Current Compatibility with
the Part Thickness.
Extensive written data
has been provided on the subject of SMAW (stick welding)
reference, electrode diameters, weld current and part
thickness requirements. In my books, I focus on this subject
for the MIG process and I have written more on this subject
than any other global welding source. The selection of the
correct MIG wire diameter is an essential consideration
for attaining both optimum, robot / manual weld quality and
E-Mail from Shawn.
Question: Ed on our robot application we have a multi-process,
pulsed MIG - short circuit - spray power source. We weld auto
thin gage steel parts from 1 to 4 mm with an 0.035 wire. Is
there a defining line when we should switch from one weld transfer mode to
Shawn this is a great question.
 For robot applications < 0.070 I would use short circuit
before pulsed. The short circuit mode is an arc on / arc off
weld transfer and therefore provides less potential for weld
burn through, especially if weld gaps are involved.
 For applications 0.070 to 0.150, pulsed MIG fits the bill and will
typically allow the use of higher wire feed rates than short
circuit, however if gaps greater than 0.060 occur remember
to set the parameters to short circuit. .
Robot welding on parts > 0.150 to 4 mm, take your choice of spray or pulsed.
If using spray use an 0.035 wire at the transition point.. If the welds are is too
hot consider pulsed and an 0.045.
Weld Current and Welder Appeal.
The optimum spray current that provides ideal weld puddle
control with the 0.045 MIG wire is typically found between
250 and 380 amps. Manager should be aware that welders do not like the weld heat generated
from spray transfer once the weld current passes 360 amps as required
with both the 0.052 (1.4mm) and 0.062 (1.6mm) wires.
Often when using the large diameter wires, and this applies
also to >0.062 and larger flux cored wires, you will find
that too keep the manual weld heat at a comfortable welding
level, the welder will set the large wires at a low current = low wire
feed setting. Few weld supervisors check a welders wire feed
settings, and even fewer understand the potential weld
deposition rates and weld costs that can be attained.
What about large welds? When welding steels > 3/8, multi-pass welds are required. The best approach to multi-pass fillet - groove welds is to make each weld pass the equivalent of a 1/4 (7mm) fillet. This enables the best control of the weld fusion and stringer weld speeds that minimize oxidation. The weld wire that provides the best control of a 1/4 fillet is an 0.045 wire. The bottom line, the large wires rarely provide deposition benefits and typically produce more weld
smoke and spatter than
attained with the more manageable, smaller 0.045 MIG
you are not still taking notes, as I can keep writing about welding at a greater rate than you will be reading.
Invest in yourself and
consider one of my books or training resources. This book is my robot - manual MIG self
teaching process control book. It's available in both English
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questions all directed at weld process control and weld
parameter selection simplification through the easy to leran weld clock method.
For your weld shop training needs you would purchase three items. This self teaching
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programmers, robot operators, QA personnel, weld supervisors,
managers and engineers, all will benefit from this valuable
weld process resource.
If you are just entering the weld profession, you will be glad to know that
weld renumeration in 2012 is just about where it was 25 years ago.
You can pulsed MIG, spray transfer or regular TIG when welding
but with all alloys you will get the best weld results with TiP TiG.
Traditional orbital TIG grade 2 Titanium
Manual TIP TIG grade 2 Titanium
While using the slow manual or automated TIG process, there is always concern about excess weld heat and the oxidation effects on Titanium alloys.
Typically manual or mechanized titanium TIG welds on parts over 3 mm will be carried at weld speeds in the 3 to 5 inch/min range. To protect those low speed high heat welds, cumbers om trailing shields have been a critical weld requirement minimize the effects of oxidation.
When welds are subject to oxidation you know weld porosity has to be an issue. The high TIP TIG weld speeds and weld TIP TIG weld agitation will produce the cleanest possible titanium welds.
With either the manual or automated TIP TIG process, TIP TIG titanium weld speeds will be much faster. Typically 10 - 30 inch/min. The higher weld speeds enable the TIP TIG welds on on some titanium > 5 mm applications to produce silver welds without the use of a trailing shield.
If your organization uses regular TIG on Titanium, you will be pleased to know that with TIP TIG, those manual or automated titanium welds can typically be carried at 100 to 700% faster weld speeds with superior weld quality.