Pulsed MIG Welding.
MIG Weld Equipment and Pulsed MIG Weld Reality.As this site is
updated frequently pleaserefresh each page before you start.
If you want to read how pulsed MIG caused weld cracks on
Fordaxles, continue to pulsed section 2 which is at the bottom of
this page.
2013: PULSED MIG, IT'S A DIFFERENT PROCESS WHEN USED WITH
AUTOMATION: It's important that the weld industry understands the
reasons why the pulsed MIG process when used with automation such
as mechanized pipe welds or robots will typically produce superior
weld quality than when pulsed MIG is used as a manual weld
process.
As many in the oil and energy industries are aware, when X-Rays
are applied to "manual" all position, pulsed MIG pipe welds, lack
of weld fusion is a common defect. In contrast when we see pulsed
MIG used with costly, mechanized, sub sea pipe welds, or oil pipe
lines, the process can attain exceptional pipe weld quality and
productivity.
When dealing with mechanized, pulsed MIG pipe weld equipment as
found with oil industry pipe applications, you will often find
multi-gun units with sophisticated pulsed weld eqipment and
controls. The pulsed equipment will provide dedicated pulsed MIG
weld programs suited to the unique requirements necessary for the
pipe weld roots, fill and cap passes.
IN THE PAST, TRADITIONAL CONSTANT VOLTAGE (CV) MIG EQUIPMENT
FROM ONE MIG EQUIP MANUFACTURE WAS VERY SIMILAR TO THE CV MIG POWER
SOURCES AVAILABLE FROM JUST ABOUT EVERY OTHER GLOBAL MIG EQUIPMENT
MANUFACTURER. WITH CV EQUIPMENT, LIFE WAS SIMPLE, DEPENDING ON THE
WELD PARAMETERS SELECTED, YOU ATTAINED EITHER SHORT CIRCUIT,
GLOBULAR OR SPRAY TRANSFER.
SINCE IT'S INTRODUCTION IN THE EIGHTIES, I HAVE BEEN EVALUATING
THE PULSED EQUIPMENT FROM GLOBAL MIG EQUIPMENT MANUFACTURERS. IN
THE TESTS OVER 25 YEARS AGO, I SAW THAT THE ELECTRONIC DIFFERENCES
AND RESULTING PULSED ARC CHARACTERISTICS BETWEEN ONE PULSED MIG
EQUIPMENT MANUFACTURER AND ANOTHER MANUFACTURER, WERE EXTENSIVE. IN
2013 LITTLE HAS CHANGED.
Ref pulsed MIG pipe welding concens:API. 5.2.3 states that the
Pulsed Gas Metal Arc Welding (GMAW-P) process may be used for any
material thickness. However whenever the welding system is changed
or the settings on existing equipment are"significantly
altered",the fabricator should verify the reesulting weld
properties. The extent of verification or testing should be as
agreed between the purchaser and fabricator.Response from Ed's MIG
WELD REALITY. In contrast to the traditiona, two control, MIG or
flux cored weld process, there are many weld essential variables
that can be readily changed with the pulsed MIG mode. While the API
code engineers warn against a "SIGNIFICANT change in a pulsed
settings", the real world weld decision maker needs to be aware
that an insignificant parameter change with the highly sensitive
pulsed MIG mode, will have a significant influence on the weld
fusion, and that weld fusion will in most instances will be
marginal or lacking.
While on the subject of pulsed MIG, the API code does not
discuss the mechanized versus manual pulsed welding
inconsistencies. When a code body stipulates that a fusion
sensitive process is OK for any pipe thickness, the code is sending
the message that this process is acceptable for both manual and
mechanized welds.With automated pulsed MIG pipe line welds,
electronic power source features such as volt or current energy
spikes can be applied to the weld weave dwell times. These
increased energy spikes will impprove the pipe side wall weld
fusion. Also the controlled pulsed MIG weld speeds, controlled
mechanized weld weaves and constant wire stick out will have a lot
to do with success of the mechanized pulsed MIG process when used
for pipe line welds.Without these controls, for three decades the
manual pulsed MIG weld process has proven that the attainment of
100% X-Ray all position pipe weld quality is a challenge, and this
is a challenge that weld shops in 2013 do not have to face when
they can use the far superior TiP TiG process.
Pipes and weld process choices..
Ten years ago STICK and FCAW were most common processes for pipe
welds.
PULSED MIG AND PIPE PROJECTS: Large pipe projects especially in
the oil industry will today often use a mechanized, multi-torch,
pulsed MIG unit for the pipe welds. The pulsed MIG equipment may or
may not have a level of electronic sophistication way beyond that
available in standard pulsed equipment sold for manual pulsed weld
applications.
For mechanized pipe root welds, either the MIG CMT - STT - RMD
modes will typically be selected, and for the pipe fill - cap pass
welds, the more conventional pulse mode will be selected. Apart
from the dedicated pulsed programs for the pipe fill and cap passes
with the pulsed equipment, you will also find the pulsed equipment
and controls may enable unique pipe weld attributes. For example
the equipment may have the capability to provide a current or volt
spike during the weld dwell time in the weld weave cycle.
Vee and J groove pipe welds have simple weld requirements.
Moderate MIG weld energy is required across the hot groove weld
surface, and higher weld energy with dwell times is beneficial when
applied to the Vee or J groove side walls, (the thicker the pipe
the higher the side wall energy required). The weave dwell energy
spike from this unique pulsed process can overcome the common
pulsed MIG side wall (lack of weld fusion) weld issues, (a
sophistication at this time not possible with manual pulsed pipe
applications). Most large automated pipe applications will enable
multi-MIG guns which also add more weld heat into the groove welds
again improving the weld fusion potential. Mechanized pipe welds
also provide Constant MIG Wire Stick Out and Constant Weld Travel
Rates which enable improved weld process control and bring a weld
quality uniformity and consistency to the automated weld that again
is not be possible with the manual pulsed MIG pipe welds.
2103: LETS GET BACK TO WELD REALITY. AFTER TWENTY FIVE YEARS OF
PAINFUL, MANUAL PULSED MIG EQUIPMENT EVOLUTION, DEPENDING ON WHO'S
PULSED MIG EQUIPMENT WAS PURCHASED, MANY WELD SHOPS WILL HAVE
PROCESS THAT CAN CAUSE MORE WELD ISSUES THAN IT RESOLVES:
In 2013 we now have in North America, a few pulsed MIG power
sources that actually work in a consistent manner and may possibly
get through their 36 month warranty period without circuit board or
electronic issues. The question that needs to be asked when
selecting pulsed for manual steel and alloy steel applications was
the purchase of this sensitive process justified in contrast to the
lower cost CV MIG equipment.
There are obvious weld benefits attained for pulsed MIG aluminum
welds (alum require less weld energy than spray) and for specific
MIG stainless welds that benefit from an open arc mode that enables
lower weld heat than spray to possibly reduce distortion. Remember
the key benefit of a MIG weld mode is the ability to provide
consistent weld fusion, and on most weld applications, spray
transfer will provide superior weld fusion than pulsed. Alway
remember that Pulsed MIG is a process which spends 50% of its time
at a back ground weld current of usually less than 100 amps. The
pulsed process is also a good subsitute (in most instances not
necessary) for the gague welds that are typically welded with short
circuit, or when welding alloys that have poor weld transfer
characteristics with conventional short circuit or spray
transfer.
As many pipe welds shops have found out, ypically when pulsed
MIG is used for "manual" pipe welds that require "100% X-Rays", a
combination of variables and factors will come together and lack of
weld fusion may become a common weld defect. In contrast to SMAW
and TIG used for pipe welds, each hour pulsed MIG will typically
provides at least 10 times more weld and is therefore considered a
high deposition process. When it comes to MIG weld defects that
high weld deposition rate takes a large part of the blame.
Fig. The outside appearence was irrelevant.
If you provide what you think is an optimum pulsed MIG fillet
weld on 3/8 (9.6mm) steel plates and then provide a macro section
of the fillet weld, you will often see either marginal or lack of
side wall weld fusion. After the macro weld evaluation you may come
away with the impression that with pulsed MIG, you have a weld
process that provides a poor ratio of weld energy to the weld
deposition - mass and the weld speeds provided. Also with manual
pulsed MIG welds the weld energy is influenced and the weld
transfer is disrupted by the manual wire stick out variations and
the many different weld techniques that each welder brings to the
pulsed weld.
THE RATIO OF THE WELD ENERGY DELIVERED AND THE WELD MASS AND
WELD SPEEDS THAT RESULT IS ALSO AN ISSUE WITH MIG SPRAY TRANSFER,
HOWEVER THE WELD SHOP NEEDS TO REMEMBER THAT WITH PULSED MIG THE
WELD SPENDS 50% OF IT'S TIME WITH A BACK GROUND CURRENT < 100
AMPS.
WELD PROCESS EXPERTISE CAN OFTEN OVERCOME POOR WELD EQUIPMENT
TECHNOLOGY. IN THE 1990s, I SET OPTIMUM PULSED WELDS ON THE WORLD'S
MOST COMPLICATED ROBOT WELDS.
Fig.. The most complex welds are small pipe and tubes, that have
difficult acces and 100% X-Ray
THE EASIEST PIPE WELDS TO MAKE ARE LARGE DIAMETER PIPES (EASIER
TO FOLLOW THE RADIUS AND MORE TIME TO REACT). IN CONTRAST THE MOST
COMPLEX PIPE WELDS ARE SMALL DIAMETER PIPES AND TUBES.
I remember in the 1990's, when the management team at one of the
world's largest engineering companies decided to purchase a seven
axis robot to weld it's boiler tubes to headers. The above picture
is not the parts welded but similar and the tubers were slightly
larger. The boiler head pipes were approx. 8 - 10 diameter,
typically 20 to 40 feet long with the 2 - 3 inch diameter thinner
wall tubes. The robot traversed on a track placed on the other side
of the header. These complex ASME welds were typically carried out
by the highest skilled manual TIG welders. I won't go into why the
management should not have selected a costly robot for these welds,
however I would like to tell you about the pulsed MIG welds I
produced on this robot application.
For each boiler tube to head weld, two robot pulsed MIG weld
layers were required to fill the grooves and produce the fillet
around the header. The pulsed MIG welds had to pass 100 X-Ray as
per the ASME requirements. As the robot could not go 360 degrees
around the tubes each of the two weld layers was made with four
passes so four weld start - stops was required for one layer, with
a total of 8 start - stops for the completed 2 weld layers, by the
way no grinding or human involvement was allowed for the weld
layers.
THE PULSED TECHNOLOGY WAS ONLY 10 YEARS OLD. THE ELECTRONICS
WERE STONE AGE AND NOT UP TO THE TASK SO I USED PROCESS EXPERTISE
TO ACHIEVE THE ASME PIPE WELD QUALITY:Can you remember how poor
computers were in the early 1990s? well I want you to try and
imagine how bad the global electronic pulsed MIG equipment was at
that time. I had a sophisticated robot attached to to an
inconsistent - erratic pulsed power source and had to provide
optimum weld quality with vertical up, tube to header welds on two
very different part thicknesses. In those small circular welds we
had 8 weld starts and 8 weld stops that required perfect weld
tie-ins to get past the X-Rays.
REMEMBER WITH SMALL DIAMETER MIG WELDED APPLICATIONS AND WITH
SMALL WELD LENGTHS, THE WELD ARC ON TIMES MAY BE MEASURED IN A FEW
SECONDS AND YOU NEED TO RELY ON THE WELD EQUIPMENT AND CONTROLS TO
GO FROM WELD START DATA TO THE WELD DATA AND TO THE WELD END DATA
IN THOSE FEW SECONDS. THE REALITY IS 2013 FEW AUTOMATED UNITS ARE
GOOD AT PROVIDING THIS FUNCTION, SO IMAGINE WHAT WE HAD TO WORK
WITH IN THE 1990s.
All the tube to header welds needed was one poor weld tie or
lack of fusion and the ASME, 100% X-Rays would mark the weld as a
failure. I used all my MIG weld process control expertise to make
these robot welds work and produce an eight hour weld quality with
better weld productivity and no more weld rework than that attained
from the manual TIG welders. How did i solve the weld fusion - weld
tie in issues?. For the side wall weld fusion I used robot weave
dwell times and kept the pulsed MIG weld mass as thin as possible.
For the weld start - stop tie-ins, with the robot weld end - start
data, I used low wire feed than the weld with higher weld voltage
which with carefullly selected dwell time provided good tie ins,
(creating a dwell time energy spike) which is similar to what is
today, >17 years later being used by oil companies and there
much more conntrolled, sophisticated, pulsed MIG equipment. I
trained a technician to make those robot welds and soon after he
quit and I believe the robot was eventually put out to pasture. In
2013 the tube to header welds would still be a high risk robot
application especially when you can now do these welds with the
easy to use TiP TiG process. www.tiptigusa.com.
1990s.. Ed (left - right) comparing MIG short circuit versus the
STT and RMD MIG weld modes on Imperial oil, nat gas pipe.
WELD CODES, CONFUSION OR INADEQUATE INFOMATION.When it comes to
MIG and flux cored welding, rather than providing weld process
resolutions, most codes relevant to pipe welding will provide
inadequate information or the information they provide simply adds
to the global weld process myths and confusion.
Welding decision makers often look codes such as AWS - API and -
ASME to provide practical, pipe welding advice and recommendations.
Those individuals that that put all their faith in the codes that
are governing the specific weld applications they are working on,
need to be aware of a little weld reality, The weld information in
these codes has too frequently been written and influenced by code
committee individuals who lacked MIG / Flux Cored weld process
controls & best practices / application expertise.
50 YEARS AFTER THE INTRODUCTION OF THE "MIG PROCESS",AND 35
YEARS AFTER THE INTRODUCTION OF FLUX CORED ELECTRODES, THE PRIMARY
WELD CODES WHEN ADVISING ON THESE PROCESSES STILL CREATE CONFUSION
AND TOO MANY QUESTIONS.API. 5.2.3 Pulsed Gas Metal Arc Welding
(GMAW-P. This code states that the pulsed process may be used for
any material thickness and whenever the welding system is changed
or the settings on existing equipment are"significantly
altered"then the fabricator should verify the weld properties. The
extent of verification or testing should be as agreed between the
purchaser and fabricator.
In a world in which engineering standards should apply, what the
hell does significantly altered mean.In contrast to the
traditionaL, two control, MIG or flux cored weld process, there are
many weld essential variables that can be readily changed when
utilizing the pulsed MIG mode. While the API code warns against a
"SIGNIFICANT CHANGE" in a pulsed settings", the real world weld
decision maker needs to be aware that an insignificant, small
parameter change with the highly sensitive, manual pulsed MIG mode,
can have a significant influence on the weld fusion attained.
While the code bodies in 2013 have very little negative to say
about pulsed MIG process, for those of you with grey hair, you may
remember that these same codes typically either did not allow
regular MIG or the code weld specifications made incorrect
recommendations or negative comments on the use of MIG. For
example, for five decades, the MIG short circuit process has been
treated like a leper, yet the weld reality was and still is in
2013, the Short Circuit mode is the best weld transfer mode for
carbon steel, "rotated" pipe, open root welds.
Most of the pipe shops which were embedded with the SMAW and TIG
process would typically not consider using the MIG spray transfer
mode for rotated pipe welds, yet the reality has been that MIG
spray transfer on the rotated pipe applications should provide
superior weld fusion and less porosity than any pulsed MIG
transfer.
THE POOR PULSED MIG WELD MASS TO WELD ENERGY RATIO:
What most weld decision makers and QA personnel are not aware,
is that there is on most all position, pulsed MIG pipe weld
applications thicker than 6mm, a poor ratio between the moderate
pulsed MIG weld energy attained, (influenced by peak to low back
ground current changes) and the high weld deposition rates that
typically result. The healthy pulsed MIG weld deposition rates push
the high weld speeds, (faster weld speeds don't help weld fusion)
along with the resulting large weld mass (larger weld mass creates
a hinderance to the weld energy produced).
For those of you moving aggressively forward with the manual
pulsed MIG process for your all position pipe welds, do not be
surprised even when using the highest manual welder skills, when
you X-Ray those sluggish stainless or nickel alloys to find lack of
fusion.YOUR LOCAL SALES REP WONT TELL YOU THIS BECAUSE THEY ARE NOT
AWARE OF IT. OPTIMUM PULSED MIG WELD FUSION WITH MANUAL WELDS WILL
OFTEN BE CONSIDERED MARGINAL, AND MARGINAL WELD FUSION WILL BE MADE
WORSE BY THE MANY PROCESS AND HUMAN VARIABLES THAT INFLUENCE THOSE
MANUAL PULSED MIG WELDS.
THE CODE RULES SHOULD CHANGE WITH AUTOMATED PULSED MIG
WELDS:
I am not aware of any code that discusses the mechanized versus
manual pulsed welding differences and the weld quality consequences
of those differences. When a code body puts it's stamp of approval
on a weld process such as Pulsed MIG, the code is sending the
message that this is process that's acceptable for both manual and
mechanized pipe welds.
With automated pulsed MIG pipe line welds in which the use of
multi-MIG guns is typical, electronic MIG power source features
such as volt or current energy spikes can be applied to the weld
weave dwell times. These controlled, increased weld energy spikes
will improve the 5G pipe side wall weld fusion. Also the controlled
pulsed MIG weld speed, the controlled, mechanized weld weaves and
the constant wire stick out. are the automated features that will
have a lot to do with success of the mechanized pulsed MIG process
when used for pipe line welds.Take away these important controls
and as it's been for three plus decades the manual pulsed MIG
process has proven that the attainment of 100% X-Ray all position
pipe weld quality is a challenge. By the way this is a challenge
that weld shops in 2013 do not have to face when they can use the
far superior TiP TiG manual or automated weld process.
API. 5.2.2 Short Circuiting Gas Metal Arc Welding (GMAW-S). The
use of GMAW-S shall be limited to the following conditions:
[] For vertical welding, the root pass and second pass
progression for a material of any thickness may be either uphill or
downhill.
Ed's response. There is no logic in using MIG short circuit,
with the vertical up position on any weld application. Just as
there is no logic in this cold process being used for the second
pass which from a weld fusion potential is the most sensitive part
of any pipe weld..
[]The fill and cap pass for butt or fillet welds may be welded
with the short circuit process, provided the thickness of any
member does not exceed 3/8 in. (9.5 mm) and vertical welding is
performed with uphill progression.
Ed's response. Watch out for lack of weld fusion with the short
circuit process welding vert up on any steel parts > 1/8 (> 3
mm0..
Ed testing both the short circuit and STT processfor Imperial
Oil. Weld focus at the difficult 5 to 7 o'clock positions.LETS GET
BACK TO 2013 AND MANUAL PULSED MIG WELDS. IT'S A SIMPLE FACT THAT
IN AN INDUSTRY IN WHICH PLAYING AROUND WITH TWO SIMPLE MIG CONTROLS
IS THE NORM, YOU WILL TOO FREQUENTLY FIND THAT WELD SALESMANSHIP
OFTEN PLAYS A LARGE ROLL IN THE PULSED EQUIPMENT PURCHASE,
A point managers need to address when purchasing pulsed MIG
equipment. Was the person who selected the pulsed MIG equipment in
full control of the traditional MIG equipment that's been around
for decades. If they were in control of the lower cost CV MIG
equipment, they should not have been having MIG weld quality -
productivity issues with most steels and alloy welds.
IT'S 2103: PLEASE NOTE THIS SITE HAS BEEN HERE SINCE 1997,
CONSIDER IT A BLOG, A HISTORY OF WELD ISSUES AND EXAMINE HOW WELD
PROCESS AND EQUIPMENT PROBLEMS OF THE PAST ARE SO OFTEN RELEVANT
TODAY. ENJOY REGARDS ED CRAIG. www.weldreality.com.
As a result of more than two decades of poor performing, erratic
pulsed MIG equipment, the global MIG weld industry has flushed down
the drain, hundreds of millions of dollars in unnecessary weld weld
equipment - weld quality and productivity costs. The costs were
generated from;
[] unnecessary robot - manual weld part rejects,[] unnecessary
robot - manual weld rework,[] unnecessary robot down time,[]
operating with lower weld deposition rates (higher labor costs)
than that which could have been attained from conventional MIG
spray transfer,[] unnecessary costs for the the robot - manual
pulsed MIG weld equipment,[] unnecessary high costs for the pulsed
MIG equipment repairs.
IN THE 25 YEARS OF PULSED MIG PROCESS DEVELOPMENT, I DO NOT KNOW
OF ONE PULSED POWER SOURCE THAT WAS RECALLED DUE TO PULSED
EQUIPMENT OR WELD ISSUES. THIS PATHETIC SITUATION IS A REFLECTION
|OF THE GENERAL MIG PROCESS MANAGEMENT APATHY THAT EXISTS IN GLOBAL
WELD SHOPS?
Of course weld equipment manufacturers like ESAB, Lincoln,
Miller, Hobart and Panasonic should always act in a responsible
manner and recalled the pulsed MIG equipment that they knew had
electronic issues. Howeverif their customer (weld shops) were not
complaining, (they lacked the expertise to correctly evaluate MIG
equipment), then why would the equipment manufacturers bother with
a recall?
WELDING MOST COMMON STEEL - STAINLESS APPLICATIONS, A QUALIFIED
WELD DECISION MAKER, WITH AN UNDERSTANDING OF MIG WELD PROCESS
CONTROLS WOULD NOT SEEK THE ADVICE OF A SALES REP AND PURCHASE MIG
EQUIPMENT THAT BRINGS NO REAL WORLD WELD QUALITY OR PRODUCTIVITY
IMPROVEMENTS.
A weld reality for steel welds: The majority of the pulsed MIG
equipment purchased from the early nineteen eighties to 2013, has
been selected and purchased by individuals who lacked MIG weld
process control expertise necessary to optimize the much lower
cost. traditional, CV, MIG equipment.Note: If you want the ultimate
books and MIG and flux cored weld best practices and process
control self teaching or training resources, clickhere.
2008: Engineers, managers, technicians and supervisors who for
decades have a difficult time controlling the simple, two control
MIG power equipment, are now talking about controlling MIG
equipment with useless "wave forms".
> 2008: The electronic pulsed MIG equipment that has been
developed for more than the last two decades for carbon steel and
stainless welds is finally delivering a few real world weld
benefits, however before you waste thousands of dollars on a pulsed
MIG power source check out the following pulsed MIG informationfrom
equipment - process evaluations from Ed Craig.
IN CONTRAST TO THE LOW COST, TRADITIONAL, DURABLE MIG EQUIPMENT
THAT CAN PROVIDE OPTIMUM SHORT CIRCUIT AND SPRAY TRANSFER WELDS;[]
PULSED AND ALUMINUM MIG WELDS: Pulsed MIG provides benefits welding
< 4 mm aluminum parts. When used on alum part > 4, mm, in
contrast to spray transfer, pulsed MIG may produce inferior
aluminum weld fusion and produce welds with more porosity.
[] PULSED AND GAGE STEELS MIG WELDS: Pulsed MIG can provide
limited weld benefits for steel gage parts, (20 to 10 gage) however
the weld benefits are so limited there is no justification for the
purchase of the pulsed MIG equipment.
[] PULSED BETWEEN GAGE AND THE THICKER METALS: When manual
welding 2 to 4 mm Carbon steels and Low Alloy steels, with these
welds when used with automation and robots, the pulsed MIG process
can provide slightly higher weld deposition rates that enable
faster weld speeds. (be aware those speeds cannot be achieved with
manual welds).
[] PULSED MANUAL STAINLESS WELDS 2 - 3mm: Welding stainless or
alloys in this thickness range with short circuit and some of the
welds may be sluggish. In contrast, the open arc pulsed MIG mode
provides more weld energy, as does the start point of spray with an
035 wire with a 98 argon - 2 CO2 mix (an Ed Craig gas mix) that is
if your welders know those low end spray settings.
Note: With food processing equipment stainless thin gage welds 4
mm, the weld fusion concern factor needs to kick in, and weld
macros should be required to ensure the pulsed procedures from the
new pulse MIG are acceptable.
AN OPTIMUM PERFORMING - COST EFFECTIVEPULSED MIG POWER
SOURCE:
What do i do when testing pulsed MIG equipment? I like to be
aware of the optimum low and especially the high pulsed wire feed
settings that requires high peak current. I would examine the weld
deposition rate potential per application. I examine the
suitability of welds produced on the common thickness used in the
plant. If I am welding thin gage aluminum, I look at the fast
freeze characteristics of the weld and the weld appearance. I look
for the arc stability with short and long length weld cycle
times.
At the end of the day. In 2013 there is still no justification
for pulsed MIG equipment for welding steels. However at times when
I would require a pulsed MIG unit, as this picture indicates, I
have a preference for pulsed equipment which I believe has optimum
pulsed weld dynamics and good pre-programmed data. I like pulsed
equipment that allows me to change the primary pulsed parameters
that are suited to my specific applications, (especially important
for cladding and specific alloys). One reasonable priced,
consistent performing pulsed power source that comes to mind, is
the OTC digital pulsed MIG unit.Note: More on the pulsed weld
equipment influence in the pulsed MIGsection two and in the MIG
equipment evaluation section.
Weld Process Controls should always start in the front
office:
From an Ed Craig report to a General Motors plant. 2001:
When your managers and engineers recognize that Weld Best
Practices and Weld ProcessControlsknowledge is far more important
than the purchase of costly, useless electronic weld equipment with
bells and whistles, your plants will take a giant leap towards
establishing optimum robot weld quality and productivity.
Lincoln did not "shed any light" on thissad MIG Power Wave
application:
One customer I assisted around 2005, manufactured carbon steel
street lamps 11 to 7 gage. These are extensive yet simple manual
weld applications. On the end of the lamps a large heavy flange is
welded. The flange mounts the lamp to the floor. The flanges were
13 mm thick. There was also a weld around the pole access box,
(gage material) located near the flange.This simple street weld
lamp application, became unnecessarily complex the day the company
decided the parts should be welded with a robot.
The company ordered a Lincoln Fanuc ArcMate 100 robot. The robot
came with the Lincoln Power Wave, 450-amp, pulsed MIG power source.
The robot system was sold by AGA who had the technical support from
Lincoln and Fanuc. Almost two years after the robot was installed
the robot had never come close to its daily weld production quota.
When the robot was installed, it was placed on the lamp production
line, however as numerous weld issues occurred and the management
moved the robot to another part of the plant so the highly trained
plant personnel could play around with the robot weld settings.
After assistance of the so called robot weld experts from
Lincoln, Fanuc and AGA, the lamp company personnel "played around"
with the robot weld data for almost two years with pathetic
results. For the rest of the story, clickhere.
Is your organization ready to stop playing with weld data and
provide MIG and flux cored weld process controltraining?
I hope the following comments on Pulsed MIG and the weld process
comparisons with traditional MIG short circuit, spray and the flux
cored process, will provide you or your organization a different
perspective on the rationalization of the purchase of pulsed MIG
weld equipment and the need for process expertise.
1989. Ed was invited by the Brazilian Society of Mechanical
Engineers to give a speech on welding in Rio. Ed titled the
speech;
"Why Brazilian Engineers should avoid the robot weld mistakes of
the North American Auto and Truck Industry".
You cannot optimize a weld process in this confused industry,
unless you can separate the mistakes of the weld industries past
and be aware of the weld sales hypes that influences too many weld
shops.
< 2005: An interesting Weld Shop QUESTION:
Management should ask this question more frequently.
To Pulse or not to Pulse, especially if they want toproduce
weldswithout fusion issues and cracks.MILLER MAXTRON AND INVISION
POWER SOURCE PROBLEMS:
E-mail. From a manufacturing manager at Hayes Lemmerz.Hayes. Ed
Hayes is a global manufacturer of car and truck wheels. We use the
Pulsed MIG process for most of our wheel welds. Since we introduced
the Miller Maxtron and Miller Invision equipment to our automated,
MIG weld production lines, we have had extensive, weld production
and rework issues. The typical wheel pulsed weld problems that we
experienced with the Miller equipment were;
[1] welds skipping, resulting in weld areas that
containunacceptable and inconsistent thin welds,[2] missed
welds,[3] welds with inconsistent weld penetration,[4] weld
globs,[5] unexplained weld porosity,[6] Inconsistent weld surface
appearance,[7] inconsistent weld undercut,[8] numerous arc starts,
weld crater and weld tie in issues,[9] numerous wire burn back
issues,[10] extensive weld equipment break downs.Please give us a
call we would like to utilize your expertise.At the request of the
Hayes management, I evaluated the pulsed MIG weld issues and
quickly revealed to the Hayes management the root cause of their
extensive weld issues and that root cause was the Hays management,
the engineers and weld equipment. For the rest of this story
clickhere.
Welding steels? I now consider myself an old fart who has
evaluted pulsed MIG for more than 25 years and s its a rare event,
I will only use or recommend "manual" pulsed MIG when it delivers
real world weld quality - productivity benefits and can therefore
pay the bills.
FOR THOSE OF YOU THAT ARE LESS THAN 40 YEARS OF AGE AND THINK I
AM AN OLD FART STUCK IN A 1970 MIG EQUIPMENT TIME WARP. MY WIFE
WOULD AGREE THAT I AM OLD FART, HOWEVER I AM AN OLD FART THATS
ASSISTED OVER 1000 COMPANIES WITH THERE WELD ISSUES, AND BY THE WAY
THAT'S NOT MY PICTURE ON THE LEFT.
in the few years I have been in this business I have set some of
the world's most sophisticated automated and robot weld
applications and as the corporate weld manager with ABB, North
America Robot Div, I believe I have a little knowledge about robots
and their weld process requirements.
As someone who has been in so many weld shops in 13 different
countries, I believe I have a good grasp of weld shop culture and
weld shop management.
In 2006 I was hired as the corporate weld manager with WSI,
(Aquilex) . This is a company known for it's expertise in Nuclear
plant weld repairs and for cladding approx 75% of the world's power
plant and waste energy water wall boilers. WSI at that time used
over one million pounds of stainless and inconel weld wires on
automated pulsed MIG clad welds on the water wall tubes. This ASME
clad application actually attained unique weld benefits from the
pulsed MIG process.
I was hired by the WSI engineering manager as he believed while
his automated weld equipment had evolved past the complex water
wall clad welding needs, the actual clad weld results from the
pulsed MIG equipment and field weld personnel left more than a lot
to be desired.
The pulsed clad weld quality left extensive lack of fusion, poor
weld overlaps, extensive surface weld issues and unnecessary excess
welds with the $26/lb, inconnel wires. A major issue with the power
plants was the clad water wallwelds too often applied too much weld
heat that had a negative impact on the boiler wall longevity.
In less than three months of pulsed MIG equipment evaluation and
weld process development, I developed new pulsed MIG clad weld
practices and procedures that dramatically improved the inconel -
stainless weld quality and lowered the weld heat. The inconel clad
welds I produced, (untouched clad weld photo above) delivered over
15 lb/hr and reduced the amount of clad water wall welds required
per square foot by approx. 28%. Remember this was a company that
purchased over a 1 million pounds of clad weld wire for it's water
wall clad applications. For this application I required unique
pulsed parameters and had to develop a unique pulsed program. These
were parameters that could not be attained with the Miller, Lincoln
or ESAB pulsed MIG equipment that was part of the WSI pulsed MIG
equip evaluation.
The important thing with any clad application is minimize the
weld dilution. In contrast, the important thing with welding is
attaining consistent, optimum weld fusion. What make Pulsed MIG a
poor choice for many weld applications, makes it a good choice for
specific clad applications. The above clad welds would not be
possible with the spray transfer mode.
I started my weld journey MIG welding tractors at Massey
Ferguson, Manchester UK, in the early 1960s. I wrote my first MIG
weld process control article in the late 1970s. Exited at the
potential of Pulsed MIG, I wrote my first pulsed MIG article for
the USA. Weld Journal in the early 1980s. During the last 3 decades
I Have written four books on MIG weld best practices - process
controls and had more than 30 weld process control articles
published. In this time period I was also the Weld Product and
Training manager for four of the world's largest weld equipment
manufacturers and suppliers.
THE BOTTOM LINE, I BELIEVE I AM QUALIFIED TO HAVE AN OPINION ON
WELDS.
$10.000 for erratic pulsed MIG equipment on the left.$3000
stable CV MIG equipment used on the right.
What the weld equipment manufacturers MIG equipment mayproduce,
and what most welders will never see.
As the above MIG pulsed current - weld voltage graph indicates,
on the left you have a highly sophisticated Panasonic pulsed MIG
power source, and on the right you have a similar parameter graph
with a low cost, traditional CV MIG power source.
TRANSFERRING THE PULSED MIG WELD WIRE IN WELD DROPLETS OR A WELD
STREAM, WHO CARES?Typical concerns with pulsed MIG equipment when
welding steel components.
[] Pulsed Weld Fusion: A primary issue with the pulsed MIG weld
fusion is this process spends 50% of it's time at a typical back
ground weld current of < 100 amps.[] Pulsed arc stability is
important for weld quality. Pulsed MIG drops need to transfer
without interuption. Pulsed welds are often influenced by the power
source electronics which cannot deal with short arc lenths and wire
stick out variations and the many weld - part (like mill scale)
variables that can influence the weld transfer.[] Pulsed MIG and
vert up welds. An issue that few weld shops think about. There is a
reason why TIG welds produce the best weld quality on all position
pipe welds. TIG provides constant high weld energy with very low
deposition rates which require very slow weld speeds. High energy
and low speeds is beneficial in attaining consistent weld fusion.
In contrast, pulsed MIG provides fluctuating, moderate weld energy
with pipe weld deposition rates that can be 700% higher than TIG.
The pulsed MIG deposition leads to much greater weld mass and
faster weld speeds than TIG, this reduces weld fusion
potential.Note: The best weld process for pipe welds is revealed at
www.tiptigusa.com.
FOR DECADES THE WELD INDUSTRY SUFFERED TREMENDOUS WELD COST
CONSEQUENCES FROM THE ERRATIC PERFORMING PULSED MIG WELD
EQUIPMENT.
2013: During the last two to three decades, most of the erratic
pulsed MIG equipment required numerousE-Prom and circuit board
changes, yet as far asI am aware, not one of the major pulsed weld
equipment manufacturers ever did a pulsed MIG power source product
recall.
AN INDUSTRY THAT LACKS MIG WELD PROCESS CONTROL EXPERTISE IS AN
EASY CUSTOMER FOR WELD EQUIPMENT MANUFACTURERS THAT MAKE FAULTY MIG
EQUIPMENT, OR MAKE WELD EQUIPMENT WITH BELLS AND WHISTLES THAT
PROVIDES NO STEEL OR ALLOY STEELS WELD BENEFITS.
IN A DIRTY WELD SHOP, WELD EQUIPMENT DURABILITY USED TO MEAN
SOMETHING:Traditional CV MIG weld equipment used to last 10 to 20
years, and the weld equipment repair costs carried out by the
plant's electrician was typically a few hundred dollars. Today many
of the companies who have purchased pulsed MIG equipment will pay
$2000 to $5000 for pulsed MIG weld equipment repairs, and these
repairs are too frequently required before the weld equipment is 48
months old.
2013: Statistics that the major weldequipment manufacturers wont
discuss.[] WHAT PERCENTAGE OF PULSED MIG EQUIPMENT LASTSBEFORE IT'S
WARRANTY EXPIRED?
[] WHAT THE AVERAGE LIFE OF A PULSED POWER SOURCE IS?
[] IN A FIVE YEAR PERIOD, WHAT THE AVERAGEREPAIR COST IS FOR THE
PULSED MIG EQUIPMENT?
[] HOW MANY COMPANIES WHO USE PULSED IN ROBOT CELLS, HAVE HADTO
PURCHASE AN ADDITIONAL PULSED POWER SOURCE SO THEY HAVE A
SPARE?
[] HOW MANY HIGHLY QUALIFIED MAINTENANCE ELECTRICIANS
FEELCOMFORTABLE ATTEMPTING TO REPAIR A PULSED MIG POWER SOURCE?[]
HOW MANY COMPANIES REALLY ATTAINED REAL WORLD BENEFITS FROMTHAT NEW
COSTLY PULSED POWER SOURCE?It's a sad reality that many companies
will pay $3000 to $5000 for pulsed MIG weld equipment repairs,
which is more than the cost of a new CV MIG power source and wire
feeder.
Remember that traditional, CV power source. It's that low cost
weld power source which can provide optimum MIG - Flux Cored weld
productivity and quality, that is if you provide the weld personnel
with weld process control training. This is the MIG power source
that should last one to two decades without repairs.
What helped the low durability, higher cost, more erratic, lower
weld energy pulsed MIG process become so popular in the last two
decades?
[] In contrast to producing traditional CV MIG equipment, when
manufacturing pulsed MIG equipment, the power source manufactures
can reduce their alloy, labor and shipping costs
[] Like the auto industry, all MIG equipment manufactures are
aware that when you add electronic bells and whistles to the weld
equipment you can dramatically increase the MIG weld equipment
prices.
[] What motivates the weld sales rep? When you sell products
with lousy gross margins your only hope is to sell weld equipment
in the high dollar range and pulsed MIG equipment typically sells
for 100 to 200% more than traditional MIG equipment.Also its
beneficial to any sales organization that if the durability of your
weld equipment is reduced, the customers will have to purchase more
equipment.
Don't try this titanium weld (video below) with yourpulsed MIG
or regular TIG. the welds will fail.
Titanium Welds: TiP TiG versus the regular TIG
process.TRADITIONAL ORBITAL TIG ONGRADE 2 TITANIUMMANUAL TIP TIG ON
GRADE 2 TITANIUM
While using the slow manual or automated regular TIG process,
there is always concern about the oxidation effects on Titanium
alloys.
Typically all position, manual or mechanized titanium TIG welds
on parts > 3 mm will be carried at weld speeds in the 2 to 6
inch/min range. To protect those low speed, high heat welds,
trailing shields are a critical weld requirement to minimize the
effects of oxidation. If trailing shields are not used, the weld
shop uses extra large shielding nozzles and stops the weld
frequentlty to get the part under a specific temperature.
When welds are sensitive to oxidation you know weld rework and
weld porosity will be an issue. The high TIP TIG weld speeds and
weld TIP TIG weld agitation will produce the highest quality,
cleanest titanium welds.
With either the manual or automated TIP TIG process, TIP TIG
titanium weld speeds will be much faster.
The higher TIP TIG weld speeds will typically be in the 9 to 40
inch/min range. The high TiP TiG speeds enable most titanium welds
on parts > 4 mm to be complete, none stop and produce produce
100% silver color without the use of a trailing shield.
TiP TiG enables better than TIG quality at MIG travel rates.
This weld was made at 24 inch/min.
If your organization uses regular TIG on Titanium, you will be
pleased to know that with TIP TIG, most manual or automated
titanium welds will typically be done 100 to 300% faster with
superior weld quality and the lowest possible weld heat.
visit www.tiptigusa.com.
AN IMPORTANT WELD COST REDUCTION MESSAGE TO ALL DEFENCE
CONTRACTORS: As reported in the 2009. September. AWS. Weld Journal,
the above (left frame) orbital Titanium welds were carried out on
US Navy ships. On one ship approx. nine orbital TIG weld units were
used to weld CP Grade 2, titanium welds. The titanium welds were
required on more than 12000 feet of titanium pipe which was used on
each ship.
Typical automated weld travel rates from the costly orbital weld
equipment was 3 - 4 inch/min. If they had selected the TIP TIG
process on the orbital units, the TIP TIG welds would have been
made at minimum weld speeds of 12 to 25 inch/min producing a
dramatic reduction in weld heat input, (less chance for
oxidization) with no weld quality issues or costly weld rework
concerns. It's also reality that with the TIP TIG weld benefits,
these titanium welds could be made with the same quality and
productivity with manual TIP TIG welders instead of that costly
automated equipment. You don't have to be an accountant to figure
out the dramatic equipment and labor cost reductions (over 2
million dollars on this one weld project) if the engineers had look
forwards instead of back wards.
Any manuafacturing manager who is worth a pinch of salt,
knowsthat if it sounds complex, it likely should not be in a weld
shop
In an industry that does not think twice about playing around
with a 50 year old, two control, traditional CV, MIG power source,
we have the following BS?
|
< 2010. DURING THE LAST TWO PLUS DECADES OF SLOW PULSED
EQUIPMENT DEVELOPMENT, (THANK GOD COMPUTERS EVOLVED AT A MUCH
FASTER RATE), MOST PULSED MIG EQUIPMENT WAS PROVEN TO PROVIDE NO
WELD BENEFITS FOR MANUAL MIG OR HIGH SPEED ROBOT WELDS ON CARBON /
LOW ALLOY STEEL APPLICATIONS, YET THE MAJORITY OF NORTH AMERICAN
WELD SHOPS COULDN'T BUY THEM FAST ENOUGH.
IS THIS THE NEXT BS YOU WANT TO SEE AND HEAR IN YOUR WELD
SHOP?
The unique $12000 MIG power source called called X-MIG, is
controlled by a palm pilot. This power source offers artificial
intelligence with adaptive synergic controls. You know you cannot
control a weld without wave forms andX-MIG provides five million
wave form variations.
With X-MIG you get fuzzy, weezy, fuzzy woozy logic and triple AC
pulsed on triple DC pulsed. X-MIG also provides a refined super
adaptive turbo pulse which givesthe arc an additional boost.
included withthe X-MIG, is a modified short circuit mode called
MSC.
Your new, X-MIG power source can also be hooked up to the
welder's cell phone or I-Pod, and controlled if you feel the need
with the palm pilot through the ethernet.
X-MIG comes with a two week warranty, (check small print for
warranty clauses) and there is no return policy. By the way as we
feel we are not responsible for the performance of this power
source we feel you should be aware that it has never been field
tested correctly. To order this unique, useless MIG equipment,
which cost the price of a small car, contact the industry leaders
in new weld technology, at askaweldsalesman.com
Could your weld shop produce a better weld than this?
Ed made the above Robot weld and the manual MIG weld below,
using spatter free, MIG spray transfer from a $3,500 traditional,
CV. MIG power source that had no electronics.
CV MIG Spray weld.
The low cost, durable, 400 amp, CV MIG power sourceI utilized on
the above spatter free spray weld, was developed four decades
before Wave Forms and Fuzzy Logic became weld weld sale's buzz
words.
THE MORE COSTLY THE PULSED MIG EQUIPMENT, THE MORE COMPLEX AND
MORE EXPENSIVE THE MIG WELD EQUIPMENT REPAIRS. .WHEN THE
MAINTENANCE SUPERVISOR SAW THE NEW PULSED MIG EQUIPMENT, HE
REALIZED HIS ELECTRICIANS WERE SIMPLY NOT CAPABLE OF FIXING THE MIG
EQUIPMENT.
THE SUPERVISOR HAD A DIFFICULT TIME FINDING A LOCAL EQUIPMENT
REPAIR SHOP THAT COULD PROVIDE THE NECESSARY ELECTRONIC PULSED WELD
EQUIPMENT REPAIRS WITH A QUICK TURN AROUND. TO MAINTAIN HIS DAILY
ROBOT WELD PRODUCTION. HIS COSTLY SOLUTION WAS TO ORDER ANOTHER 4
PULSED MIG UNITS AS SPARES.
To purchase MIG equipment wave forms you don't need, how much
will your company this year budget for new pulsed MIG equipment and
the annual pulsed MIG weld equipment repairs? Two weeks after the
three year old warranty has elapsed on that pulsed power source,
you could end up with a pulsed MIG weld power source repair bill
that is in the $2000 to $5000 range. The bottom line after that
expensive repair, that three year old pulsed power source is the
equivalent of a 10 year old car and you know what direction that
power source is heading.
ANOTHER INDICATION OF THE LACK OF EXPERTISE AT THE MAJOR WELD
EQUIPMENT MANUFACTURES: Dec. 2008. Norfolk Virginia. I requested
that the local Miller rep bring in a Miller 350P pulsed power
source to a client of mine for a pulsed MIG demo on Aluminum. It
took 10 to 15 minutes to figure the pulsed arc characteristics were
poor (insufficient energy for the moderate rate wire feed
delivered) on the 5356 program welding 1/4 (6 mm) aluminum fillets.
I switched the aluminum weld wire to 4043, however we could not use
the equipment as the 4043 program and the arc control (voltage
control) did not work. The demo failed.TWO QUESTIONS YOU COULD
ASKYOUR PULSED MIG EQUIPMENT MANUFACTURER.
[1] YOU ADMIT YOUR PULSED EQUIPMENT HAS HAD MANY ELECTRONIC
ISSUES, YET I CANNOT RECALL YOU INFORMING US ABOUT THOSE FAULTS OR
PROVIDING COMPENSATION FOR OUR WELD ISSUES OR PROVIDING WELD
EQUIPMENT RECALLS.
[2] AS WE RESENT BEING A TEST LAB FOR YOUR EVOLVING, ERRATIC
WELD EQUIPMENT, WOULD IT BE POSSIBLE FOR YOU TO THOROUGHLY TEST
YOUR NEXT NEW MIG EQUIPMENT WITH PERSONS WHO HAVE PROCESS /
APPLICATION EXPERTISE BEFORE YOU PRESENT IT TO THIS WELD SHOP?Arc
characteristics a minor detail for somein the welding industry
.
PULSED MIG EQUIPMENT PERFORMANCE:
As this MIG volt / amp graph of a 2004 PANASONIC pulsed MIG
POWER source indicates, the weld current (black) and voltage (red)
are anything but stable and the volt current spikes are
unnaceptable.
Arc and weld energy stability with pulsed weld equipment is
something that should be a concern for any weld individual that
understands the importance of attaining consistent weld energy for
consistent weld transfer and consistent weld fusion.
High pulsed MIG wire feed rates can lead to excessive pulsed
frequency resulting in high peak current weld content, leading to
excess weld fluidity and agitated weld puddles.Ed on right
providing robot process control training for Magna plant in the USA
2004. While at Magna, he tested Lincoln pulsed Equipment versus CV
equipment - spray transfer.
The following weld test comparisons were made using a Lincoln
pulsed power source and a low cost MIG power source, the Lincoln CV
400. The Lincoln CV 400 costs approx. $3000.Compare what you pay
for your robot weld equipment. In 2004, the CV 400 robot MIG
package, including wire feed and interface, would sell for approx.
$6500. For those tier one companies who often get a twenty to
thirty percent discount on the weld equipment they purchase, did
you pay more than $4500 for your robot weld package, (power source
and interface). Every penny you spent over this price was a penny
thrown out of your window.
The Lincoln CV 400 will on the majority of weld applications
outperform the much more costly Lincoln pulsed Power Wave 455 and
any of the Miller, ESAB or Japanese pulsed equipment on carbon
steel welds. In contrast to the low cost CV equipment, the Lincoln
Power Wave unit including a wire feeder and interface will retail
for around $12000 to $14000. In this segment the Lincoln CV welds
are also compared with the Lincoln Invertec, an inverter pulsed
power source which sells for approx. thirty percent more than the
CV 400.
Using a low cost Lincoln 400: Ed made this untouched "manual",
5/16, (8 mm) fillet weld. The wire, 0.045, wire feed, 450 ipm,
delivering approx. 13 lb/hr.
Note: With this untouched spray transfer fillet weld sample, no
weld spatter, and the "flat" smooth weld surface. Also note the
spray weld's straight edges which indicate consistent weld transfer
and consistent weld fusion.
PICTURE ABOVE: With an 0.045, (1.2 mm), E70S-3 MIG wire and
argon - 10% CO2 gas mix, Ed ran the 0.045 wire at a wire feed rate
of 450 ipm. The 450 ipm is an optimum spray transfer wire feed rate
for many auto / truck frame manufactures, robot welding carbon
steel parts 3 to 6 mm. The 450 ipm wire feed rate will enable a 4
to 5 mm fillet welds at a robot travel rates of 40 to 50 ipm. This
deposition rate will also produce a 1/4, (6 mm) fillet weld at a
robot speed of 20 to 22 ipm.
Pulsed MIG versus MIG Spray.0.045 (1.2mm) wire set at 350
ipm.
Picture above. I produced the pulsed weld on left sample with
the 0.045 wire. Compare it with the spray weld I made on the right
using the same wire size, the same technique, the same WSO and same
wire feed rate using conventional CV spray. Both welds were made
with the wire feed set at 350 inch/min delivering approx. 9 - 10
lb/hr. When set at 350 inch/min the 0.045 wire is at an "optimum"
pulsed wire feed setting. The 0.045 wire set at 350 ipm is also the
approx. "start point" of spray transfer weld. Again note the pulsed
weld inconsistency is clearly evident in the convex, irregular weld
surface and inconsistent weld edges. When sectioned, you know which
of these two welds provided superior weld fusion.
If you want robot weld stability at high weld deposition rates,
purchase a CV power source and pay approx. $6000 rather than waste
$12000 plus on pulsed MIG equipment. If you have already spent your
dollars on that pulsed power source and want to improve weld fusion
or arc stability switch over to spray transfer.Pulsed MIG versus
MIG Spray. 0.045 (1.2mm) steel wire set at 450 ipm.
Picture Above: Again you don't have to be a weld expert to see
that when the 0.045 wire is set at 450 ipm, (approx. 13 lb/hr),
which weld is optimum. The 0.045 wire set at 450 ipm is used on
many robot spray welds on parts > 5 mm. This one picture tells
you why auto industry executives and engineers have wasted millions
of dollars on paying an expensive premium for electronic pulsed
equipment that has not created any steel weld benefits for their
plants
.Pulsed MIG versus MIG Spray. 0.045 (1.2mm) steel wire set at
550 ipm.
PICTURE ABOVE: Of course if you want the maximum possible MIG
weld deposition rate or highest ROBOT weld speeds from the robots
on steel parts > 8 mm you will use an 0.045 wire set around 550
ipm,15 to 16 lb /hr.This is a common spray wire feed setting you
don't want to set with that costly pulsed power source. One thing
you can say for the pulsed process, at low or high wire feed rates
the weld inconsistency is consistent.
IT'S ALSO TRUE WITH 0.035 (1mm) WIRES.
PICTURE ABOVE: With the 0.035 wire and argon 10% - CO2. I opened
the wire feed control to it's maximum setting and provided a wire
feed rate of 700 ipm. Again look at the spray weld on the left
versus the pulsed weld on the right. The pulsed weld with the 0.035
wire indicated the same inconsistent weld transfer pattern as with
the 0.045 wire. The pulsed weld was again more irregular and convex
and the side wall weld fusion was again less inconsistent than the
spray weld. Again note both welds are untouched with no
spatter.
In the pictures below the 0.035 wire was set at an optimum mid
range pulsed wire feed rate of 550 ipm Compare with the MIG spray
weld made with the same wire feed rate on the right and you can see
which weld is more stable.
Picture Above. Again note the 0.035 wire comparison of the
pulsed mode versus spray transfer weld. In the pulsed picture on
the right, the welds are made at a mid range wire feed setting of
550 ipm. As the weld indicates again the traditional spray mode
shows more consistency in the metal flow rate.
If you want the most effective robot and manual MIG andflux
cored weld process control training program, visithere.
Ed's process control training resources.
Pulsed MIG welding Torque Converters:
This costly LINCOLN POWER WAVE,was not up to the following
simple wheel weld challenge,
After years of trying to educate an apathetic big three weld
management, it's only fitting that my last auto weld consulting job
in the year 2000, ended up in a Detroit General Motors plant and
the application was using the infamous Lincoln pulsed MIG
equipment.
The GM management and engineers who typically like Ford and
Chrysler engineers are not aware of the process fundamentals that
weld their vehicals were not satisfied with their new multi-million
dollar torque converter line pulsed MIG welds. This line had been
set up to automatically pulsed MIG weld approx. 1000 torque
converters daily.
The GM torque converter parts are delivered to the weld stations
by conveyors. In the weld cells, the round parts rotate while the
MIG welding guns are stationary. The parts required a continuous
3/16 (4.8 mm) horizontal lap seal weld. Each weld station had three
MIG guns which would simultaneously weld the converters as they
rotated. The pulsed MIG weld problems generated from the Lincoln
equipment and a process that often does not deliver optimum weld
quality delivered a product with the following;
[a] The torque converters had a 4 - 8% leak rate from the multi
MIG pulsed welds. In the auto industry this leak rate in some
plants would be considered good, however at this GM plant, as the
weld production volume was extensive, the finished machined torque
converters were very costly and weld repairs were not allowed.[b]
Excess weld heat from the multi-torch operation was also causing
production "assembly" issues.
The Lincoln pused weld equipment arc weld instability at
recommended pulsed wire feed settings established by Lincoln
engineers and technicians caused extensive weld quality issues,
weld rework and productivity issues for GM. The GM engineers had
worked out the annual weld rework and loss of productivity losses
for this plant would be in the range of 1.5 to 2 million dollars.
For a little weld process logic from Ed who fixed the problem and
never even got a thank you card from Lincoln and for the the rest
of the storyclick here.
2004. Another Pulsed MIG Problem from Miller and I waswondering,
do those guys at Miller know what defines a good weld?and do they
ever test their pulsed MIG equipment before they release the new
models?
2004: This time my pulsed MIG application was a major tier one
manufacturer of stainless exhaust coupling and flexible fittings as
used in the auto / truck industry. The tight tolerance, stainless
parts, are rotated in an automated Bancroft welding machine with
the single MIG gun stationary. The stainless MIG welds were made
inside the flange. With these automated parts I was again provided
the opportunity to evaluate pulsed MIG versus traditional
spray.
To weld the stainless coupling parts, the manufacturer had
selected Miller Invision pulsed MIG equipment and the weld transfer
mode utilized was the pulsed MIG mode. The 0.045 (1.2mm) 300 series
stainless weld wire was set at what should have been an an optimum,
conservative pulsed wire feed rate of 300 ipm with optimum weld
volts. After welding each part, the parts were leak tested. The
pulsed welds looked good, yet the average weld rework as revealed
by the leak test was over ten percent.
To fix the leaks, I first switched off the pulsed mode and
within a few minutes established new "spray transfer" weld
parameters. With the spray mode I set the 0.045 wire feed rate
higher, at "400 ipm". With the higher spray wire feed rate I
increased the actual weld production by 25%and the leak test for
the new spray transfer welds was "zero percent".
AS THE WELD TRAVEL RATE AND WIRE STICK OUT WAS CONSTANT, THIS
WAS A GREAT APPLICATION TO COMPARE THE MILLER PULSED MODE WITH
SPRAY TRANSFER. To reevaluate the pulsed mode at the same wire feed
rate set with the the spray weld, I then reset the Miller Invision
power source back to the pulsed mode and set the pulsed wire feed
rate at 400 ipm. I then fine tuned the pulsed parameters to
minimize spatter with the shortest optimum arc length. The new
pulsed welds looked as good as the spray welds, howeverwhen the
parts were leak tested approx. 8% of the pulsed MIG welds required
weld rework. I turned the pulsed mode off and from 2005 and these
important auto / truck part welds are made the old fashioned Ed
Craig way, using "spray transfer".WITH PULSED MIG, IT'S OFTEN WHAT
YOU DON'T SEE WITH THE WELD THAT SHOULD BE A CONCERN.For those of
you struggling with consistent pulsed MIG quality welds, be aware
that in most instances the traditional spray transfer arc on parts
> 3 mm can provide superior weld fusion and be more stable.As
much as weld equipment companies benefit from making their weld
equipment complex and costly, please note MIG welding has never
been rocket science. The wires in your $10 Chinese toaster provide
the correct amount of resistance and current to maintain the wire
in a consistent red heat condition.
As the photo on the right indicates, for a few hundred dollars,
you can put two car batteries together. With the 24 volts hooked up
a small spool wire feeder gun you can then produce an excellent MIG
weld.
In the simple task of melting the tip of a small diameter, MIG
wire, weld equipment manufactures today don't blink as they offer a
sophisticated, electronic pulsed MIG power source at the cost of a
small car. If you have more money than sense you know you need
pulsed MIG equipment for you steel welds.
Miller Pulsed MIG Update 2008. It's the same stainless coupling
company I visited in 2004, only this time we compare the Miller
Axcess pulsed mode against lower cost CV equipment and the
traditional spray transfer mode.
In 2004 when this auto parts supplier had problem with the
Miller Invision pulsed MIG flange welds on the stainless couplings,
I found that we could get the consistent weld results the company
desired by switching the pulsed mode off and welding the the flange
stainless welds with spray transfer. (See above story).
In 2008 Miller delivered it's new Miller Axcess with a promise
that the pulsed mode was now stable and would achieve the desired
weld quality on the automated stainless coupling welds. The
coupling company was dubious about Miller's promises so they
invited me back to compare the Miller Axcess pulsed mode against
the traditional spray mode I had previously established.The
automated pulsed MIG weld cells had a two torch setup. I set one
gun on the Miller Invision in the traditional spray mode. I set the
other gun to a new Miller Axcess and utilized the Accu Pulse mode.
I ran both systems using the shielding gas I developed for this
weld, Argon - 5 CO2. We used an 0.045 (1.2mm) stainless weld wire.
The wire feed range tested was 300 to 500 ipm.
In the weld tests the Miller Axcess performed well in the pulsed
mode. With both the pulsed arc and spray arc lengths finely tuned
tominimize spatter. The weld results were again interesting. The
Axcess package is priced about 50% more than a standard CV Miller
Delta Weld package, however the Miller Axcess pulsed mode did no
better than the regular MIG spray mode. It's true that the average
weld current from the pulsed mode was less, however lower current
on this application which was subject to leak tests was not a
benefit. As for weld spatter, the coupling weld position and small
ID create an excellent weld spatter trap, so weld spatter was a
major concern. Again the Axcess did well on the spatter count,
however the spatter results between the pulsed mode and spray mode
were so miniscule that when the pulsed and spray parts were placed
side to side, no one could tell which was the spray weld and which
was the pulsed weld. The important bottom line for this company was
there was no justification to pay the extra price for the Miller
Axcess. In the afternoonI fine tuned the traditional spray mode and
the afternoon shift ran 800 parts that required no weld cleaning
and no weld rework.IT'S LOGICAL FOR ANY WELD SHOP TO ASK, WHAT REAL
WORLD WELD BENEFITS ARE DERIVED FROM MAKING THE MIG WELD EQUIPMENT
MORE COSTLY AND COMPLEX?
WHAT DOES THE PULSED MIG EQUIPMENT HAVE TO DO TO MAKE THAT
COMMON 1/4 (6 mm) FILLET WELD? As the pulsed MIG weld wire travels
into the weld at typical speeds of 100 to 700 ipm, that highly
sensitive, artificial intelligent pulsed MIG power source has
to;[a] Control and diagnose both the pulsed arc start and arc end
weld parameters. If the preset pulsed data does not produce the
weld start or the weld end crater will your weld personnel know how
to set the correct pulsed data?
[b] Control and diagnose the pulsed low back ground current. If
the weld is unstable or lacks weld energy, does your weld decision
maker know what the optimum pulsed back ground current should be,
or what an adjustment to the back ground current will do to the arc
or weld?
[c] Control and diagnose the pulsed high peak weld current. Does
your weld decision maker know what the optimum pulsed peak would
be, or what an adjustment to the peak current will do to the arc or
welds?
[d] Control and diagnose the pulsed frequency. Does your weld
decision maker know what the optimum pulsed frequency should be, or
what an adjustment to the pulsed frequency will do to the
welds?
[e] Control and diagnose the pulsed pulsed up-slope / down slope
and the pulsed profile. Does your weld decision maker know what an
adjustment to the pulsed profile, (select one of 4 million
available wave forms) will do to the welds?
FOR DECADES SPRAY TRANSFER HAS BEEN A SIMPLE PROCESS, YET FEW
WELD SHOPS PROVIDED THEPROCESS TRAININGNECESSARY TO ATTAIN PROCESS
OPTIMIZATION.. IN CONTRAST TO THE COMPLEXITIES ASSOCIATED WITH
PULSED MIG, LOOK HOW SIMPLE IT IS TO MAKE THAT COMMON STEEL FILLET
WELD FOR ANY STEEL OR STAINLESS APPLICATION, USING A CV POWER
SOURCE, AN ARGON CO2 MIX AND 0.045 (1.2 mm) WIRE:
[1] You select one of three optimum wire feed positions, (from
myweld books and training resources).
[2] You set the optimum spray weld voltage, one of two settings
(from myweld books and training resources) then fine tune the
voltage by the sound or spatter length and shape.If the weld shop
was confused aboutthe two control short circuit and spray
modes.
what hope does the shop have understanding pulsedMIG if pulsed
parameter adjustments are required?
A traditional CV, MIG power source may be short on electronics,
however it does a great job while welding as it automatically
maintains the arc length during wire stick out variations.
The low cost, durable MIG equipment provides three unique MIG
weld transfer modes suited to all metals. Short circuit provides
controlled low heat input suited from 20 gage to 0.100. Controlled
globular produces a small amount of weld spatter and suited to weld
14 gage to 0.125 and depending of the use of robot or manual
welding, spray is suited to welding all steel parts >0.070.WHAT
ABOUT THOSE INVERTERS OR CC/CV MULTI-PROCESS POWER SOURCES?.....Did
you know the regular lowest cost CV power source is superior to an
Inverter and a multi-process or pulsed power source when used for
the MIG weld modes, short circuit or spray and for welding with the
gas shielded flux cored wires?. (This info is not available from
Miller, ESAB or Lincoln, however the evidence is available in myMIG
and flux cored Process Control training CDs.
There is a great value for any weld decision maker, when they
combine weld process expertise with a $2000 - $3000 CV power source
and a simple two part gas mix that can handle the vast majority of
the world's welding applications.
Ed providing MIG and flux cored process control trainingto 60
engineers and managers from 6 countries.
2010: MIG WELD BEST PRACTICES AND PROCESS CONTROL TRAINING FOR
WELD OPTIMIZATION. MOST COMMUNITY COLLEGES DON'T PROVIDE IT,
UNIVERSITIES THAT OFFER WELD ENGINEER DEGREES DON'T DO IT,
COMMUNITY COLLEGES THAT TEACH WELDING RARELY DO IT, AND WELD SHOPS
GIVE IT MINIMAL CONSIDERATION .
IF THE WELD PROCESS CONTROL TRAINING IS PROVIDED FROM MY CD, MIG
AND FCAW POWER POINT PROGRAMS, THE WELD RESULTS FOR YOUR
ORGANIZATION CAN BE REMARKABLE.
[a] WELD PERSONNEL WILL NO LONGER HAVE TO "PLAY AROUND WITH WELD
CONTROLS" TO ATTAIN OPTIMUM WELD DATA.
[b] WELD PERSONNEL WILL KNOW WHEN TO SWITCH FROM SHORT CIRC,
GLOBULAR SPRAY OR PULSED OR WHEN TO CHANGE THAT WELD WIRE SIZE OR
GAS MIX FOR OPTIMUM WELD QUALITY AND PRODUCTIVITY.
[c] WELD PERSONNEL WILL IMMEDIATELY UNDERSTAND THE ROOT CAUSE OF
THEIR WELD ISSUES AND WILL PROVIDE INSTANT WELD PROCESS RESOLUTIONS
NECESSARY FOR THE COMMON ALL WELD ISSUES.
[d] WELD PERSONNEL WILL UNDERSTAND THE RELATIONSHIP BETWEEN WELD
COSTS, WIRE FEED SETTINGS AND THE WELD DEPOSITION RATES THEY DAILY
ATTAIN.
A FEW OF ED'S WELD PROCESS OPTIMIZATION PROJECTS,
FORD F 150 FRAMES - VOLVO CABS - CORVETTE FRAMES- HARLEY FRAMES
- NEW BEETLE SEATS AND ED ALSO ESTABLISHED THE ROBOT WELDS FOR THE
WORLD'S LARGEST CATERPILLAR TRUCK.
click here for Ed's best practices / process control
materials.
ARE YOUR PEOPLE WELDPROCESS QUALIFIED?
Why not give the personell who make weld decisions
thisFUNDAMENTAL MIG WELD PROCESS CONTROLTEST
HOW FAR IN THE WELDING INDUSTRY DID WE EVOLVE BETWEEN 1988 AND
2008? In the graphs below we have two MIG welds both set with
optimum weld data. If you believe in the importance of MIG arc
stability take your choice. Compare the spray voltage (red) and
current (black) graph on right from a regular $2000 MIG power
source built in 1988, with the optimum pulsed mode graph on the
left from a $12.000 USA manufactured pulsed power source built in
2008.
Even lawyers could figure this weld equipment performance graph
out.
In one weld process control presentation I provided a process
control work shop with a large group of ASTEC / Kolberg managers
and engineers. There was two lawyers present, ready to give a talk
on patents. I asked the lawyers which of these graphs they would
accept in the attainment of consistent, optimum MIG weld quality.
You know they both picked the one on the right.
The next two pictures are are two 3/16 (4.8 mm) fillet welds I
made during 2003 on 1/4 stainless steel. The welds were made with a
Lincoln 300 Power MIG. The 300 power source was a single phase,
pulsed MIG unit that retailed at that time for approx. $3,700. This
pulsed MIG power source has pre-scheduled pulsed programs for
specific wire types and diameters.
This Lincoln pulsed MIG power source was purchased by a company
that welds both steel and stainless parts. Due to it's daily
welding issues, (most caused by lack of process expertise) this
company believed it needed Lincoln's so called unique pulsed power
source. The MIG wires used for the 3/16 fillet welds were 0.035,
(1mm) - 308L and 309 wires.
With the Lincoln power source, I set the 0.035 wire feed at 550
ipm, a setting that should have been an optimum pulsed wire feed
rate. The power source provided the pulsed parameters, I simply had
to set the trim, (fine tune the weld voltage) to attain the optimum
pulsed arc length. The manual welds were untouched after welding.
Take note of the mediocre pulsed weld appearance and also the heat
affected zone in contrast to the spray photo.
Th following pulsed MIG picture is worth a thousand words.
Provide a macroexamination of your pulsed MIG weld fusion and then
compare with spray transfer.
$3700: Lincoln 300. Pulsed MIG "On".
Lincoln 300: Same wire feed settings as abovewith the pulsed
mode turned "off".
With the pulsed mode switched off, the Lincoln 300 power source
was set to spray transfer. The same weld wire and wire feed rate as
the pulsed weld were used for the 3/16 stainless spray transfer
fillet weld. As you can see above, even the spray weld was poor
with an obvious lack of weld energy. Poor slope output for spray is
common from pulsed MIG equipment. As you can see when comparing
both welds even the HAZ is similar. My point is simple. Why pay
extra for the pulsed electronics when you don't need them? Why pay
for something that provides inferior performance to traditional CV
equipment and is less durable and more costly to repair?
Check the weld similarity from the two weld transfer modes.Check
out the Lincoln poor performance for both the pulsed and spray
weld.
The above welds would be dramatically improved using the same
wire feed settings and spray transfer from a regular > 250 amp
CV power source. So we have another weld shop that purchased a
pulsed product that did not live up to the salesman promises.IF YOU
WANT TO FIND THE WORLDS WORST WELDSPAY A VISIT TO AN AUTO / TRUCK
PLANT
NO WELD EQUIPMENT ISSUES HERE,JUST LACK OF ROBOTWELD PROCESS
EXPERTISE.The following pictures are robot pulsed MIG welds made
between 2003 and 2005 on Ford truck frames. The sad looking welds
were made with one of the most expensive, American manufactured,
pulsed power source available, the "Lincoln Power Wave".
I have been in too many auto / truck frame plants and from a
weld perspective it was always a gut wrenching, frustrating
experience. I often think the coating they put on the frames after
welding is not there to prevent rust, it's there to either hold the
steel together or to make sure no one can see the welds. The
pathetic Ford truck welds shown below are of course not the fault
of the workers on the floor and not the fault of the robots or weld
equipment.2003 - 2004. Weld Equipment. Lincoln Pulsed Power Wave
purchased by managersand engineers who lacked the ability to take
ownership of a aimple welding process.
These Ford truck robot MIG welds were managed and programmed by
engineers with degrees and robot weld personnel who thanks to their
inexperienced management were not given the training required to
establish Best MIG Weld Practices and Robot Weld Process
Controls.
Purchase the most expensive and most sophisticated electronicMIG
equipment available. Make some bad choices on the weld wire size
selected. Mix in inexperienced, hands off weld management. Toss in
some poorly trained engineers, supervisors and technicians and you
to will have the right combination to produce truck frame welds
that look like they fell out of the rear end of a pigeon as it flew
over the parts.
What a combination, America's most expensive pulsed power source
welding on America's most expensive truck, it was a lousy marriage.
Here in the USA we can blame the loss of many jobs on overseas
lower labor costs or superior Japanese quality, which from a weld
perspective is simply a myth. If we face weld reality, we may want
blame a good portion of the demise of the Big Three and North
American job losses on under qualified, manufacturing management
who for decades lacked the ability to control and optimize the
equipment they own and therfore lacked the abilty to recognize the
process control training necessary for their plant
employees.Remember optimum MIG welds with the best possible weld
fusion are not about a unique weld transfer mode such as pulsed,
and so called unique wave forms, they are about a balance between
the stable weld energy (slope output) delivered and the weld
deposition rates and travel speeds provided.
Visit Ed's Weld Process Control TrainingResources.
THE FOLLOWING IS A CASE OF WELD PRODUCT MARKETING / SALESMANSHIP
AND BOVINE FECAL MATTER THAT FROM MY PERSPECTIVE IN HAS REACHED AN
ALL TIME LOW.
I was amazed to read one advertisement in the Nov. 2003. Weld
Journal, a magazine that often struggles to walk a line between
it's source of advertising revenue and maintaining unbiased weld
technology credibility.
The advertisement in the Weld Journal was from National
Standard, (NS), a primary North American MIG wire manufacturer. The
NS advert made ridiculous claims for it's new Pulse PLUS Steel MIG
Weld Wire.
National Standard claimed. "That with their unique MIG wire and
the pulsed MIG process you will getless weld spatter,less weld
fumesand their MIG wire willreduce the need for grinding. NS also
claimed that their pulsed wire is supposed to providea wider
operating rangethan competitive MIG wires. NS made four claims that
were simply four lies.
BS from NS with it's so called Pulsed MIG Plus MIG Wire.
When an industry MIG wire leader like National Standard has to
rely on marketing BS you know there will always be a salesman ready
to deliver it. A sad point also is the Weld Journal printed the
above add.
I guess that $12000 pulsed power source you just purchased from
Lincoln that's loaded down with sophisticated electronics that
controls the pulsed weld transfer, will now with the magic NS wire
provide an enhanced pulsed transfer.
This type of weld product advertising belongs on the very top of
the the mountain of the never ending Bovine Fecal matter that for
decades has spewed from the marketing department many global weld
equipment and consumable manufacturers. This is the type of weld BS
data that adds to weld shop myths and weld shop confusion. This is
part of the the BS that has helped destroy the technical
credibility of today's welding industry.SHAME on National Standard,
a major North American weld wire manufacturer for it's gross
product lies and complete lack of respect for the intelligence of
it's North American welding customers.
SHAME on a Welding Journal affiliated with the none profit
American Weld Society for providing this ad. This is a journal that
prides itself on it's technical articles, perhaps this journal
forgot that it only benefits it's "paid subscribers" as long as the
information and advertising it provides is credible.
SHAME ON the welding industry that's been using the MIG process
for more than five decades, an industry which still has many
gullible readers that actually believed the NS claims and purchased
this ridiculous MIG wire.This NS MIG weld wire fiasco, is yet
another reason why it's important that the global weld industry
needs to take ownership of it's processes and why weld decision
makers need to cut the umbilical cord that has been attached to
weld equipment and consumable manufacturers for more than fifty
years.
< 2005. When it comes to reading advertisements and welding
literature written by personnel who work for world's leading MIG
equipment and consumable manufacturers, before you believe what you
read, put that weld shield in place, check the wire feed rates you
can deliver, examine the arc and weld consistency, THEN CUT THE
WELDS ANDBELIEVE IN THE WELD FUSION YOU SEE.Ed Craig 2005.
E- Mail Weld QuestionJune 19, 2003.
Subject: GMAW-P Problems.Hello Ed. We are trying to utilize
GMAW-P on an HY-80 steel pipe welds. I was pushing for gas shielded
flux cored wires, but our engineers will not allow flux cored wires
for our procedures. The engineers complain of poor mechanical
properties from the flux cored wires on the HY metal. We can't use
spray as many of the welds are out of position. We are having a
difficult time passing UT with our Miller Invision pulsed power
source. The MIG pulsed parameters required provide a wide arc zone
and long arc length, this results in inconsistent weld fusion.
We are thinking about switching to Lincoln Pulsed equipment, as
they tell us with their equipment that we can control the pulsed
wave forms and get better results. The Miller Equipment does not
allow wave form manipulation from the interface, you have to run
off the factory resets. Do you have any suggestions on getting
better results with our GMAW-P equipment?
Ed's Reply: Forget that nonsense about "pulling a magic wave
form out of that red machine". Your question brings to light some
of the pulsed process issues I have been talking about for more
than a decade. Pulsed variable parameters and pulsed arc length
sensitivity combined with a lower energy, fluctuating pulsed MIG
arc plasma will have welding consequences especially to those who
are concerned about the weld fusion attained. Of course to attain
more weld energy with pulse one can always increase the pulse
parameters. However there are limits and when those parameters are
outside the optimum pulsed parameter range, you will not likely be
pleased with the resulting welds.
Good luck with the Lincoln Power Wave and it's numerous wave
forms. I think you will find that wave form control which sounds
great in the Lincoln marketing brochure is going to have have
little impact on your weld applications. You may want to read one
of my many experiences with the Lincoln Power Wave when it created
serious weld quality issues for American Axle, a major tier one
axle manufacturer. Check out the MIG equipment section.
Your statement on the engineers comments on unacceptable gas
shielded flux cored weld mechanical properties shows a real problem
in your organization and a common major problem for many
companies.
If your company is interested in attaining consistent weld
fusion and higher than traditional weld strength it should fire the
engineers who made the ridiculous flux cored statement and quickly
get used to welding with the highly cost effective gas shielded
flux cored consumables or better still take a look at TIP TIG.
Your companies weld issues are typical of many companies in the
pipe and pressure vessel industries, companies where you will find
many engineers who provide MIG and flux cored weld opinions, yet
few are qualified to make a rational MIG or flux cored weld process
decision.E Mail 01/ 2005.
Question: Ed I just recently purchased the Lincoln Power wave
355 Pulse power sources to weld 0.055 stainless steel pipe to a
much thicker 6 mm solid donut shaped carbon steel part. These are
automated welds and the nozzle to work distance is fixed. I have
been experiencing arc stability issues and INCONSISTENT weld
appearance every now and then during the circumferential welds.
Could I talk with you in more detail regarding this problem?
Sincerely. Travis Schifferns.Ed's answer. You are finding the
weld reality that the pulsed equipment you purchased does not live
up to the promises made by the equipment mfg. Call me reference the
solution to this problem. Ed.
ROBOTS AND HIGH SPEED PULSED MIG WELD CONCERNS: The pulsed,
inconsistent, lower open arc energy attained from < 2005 pulsed
equipment was not the logical choice for many high weld speed robot
applications, especially when you consider the two prime weld
quality issues on many robot welds on steel or stainless parts >
4mm was;
[1] marginal or lack of side wall weld fusion.[2] inconsistent
or skipped welds caused by inconsistent transfer of the electrons
across the arc.
SPRAY VERSUS PULSED PLASMA AND THE WELD STREAM:In contrast to
the ever changing, peak to back ground pulsed MIG transfer mode,
the constant energy, higher velocity, denser plasma with the spray
transfer weld stream, offers three unique weld attributes;[1] Spray
Transfer: With consistent weld parameters, spray transfer will
provide a less fluctuating, more consistentplasma shape and
therefore maintain the location of the arc plasma energy
influencing the weld fusion potential. In contrast to spray, the
pulsed plasma is typically weaker as 50% of it's time its at the
back ground current setting. In the pulsed back ground to peak
condition, the plasma profile continuously collapses between a
narrow and wider plasma.
[2] Spray transfer can weld with a much shorter arc length than
pulsed. The shorter arc length focuses the most concentrated area
of the arc plasma plasma energy in the weld rather than over the
external weld surface. The concentrated, higher energy spray plasma
is beneficial to attaining optimum weld fusion and stable electron
transfer with high speed welds.
[3] The traditional spray transfer plasma configuration and
short arc length potential can provide an arc less sensitive to
mill scale or specific coatings.
THE WONDER OF THE REGULAR MIG ARC: When you read anout the
pulsed MIG electronics performing miracles as the MIG arc lengths
change, remember In most robot and automated welding systems, the
MIG arc length (wire tip to work distance) variations that take
place during the welds should be minuscule. However if the constant
voltage (CV) arc length does change during the weld, the
traditional CV MIG power source has always had that unique slope
feature in which a small voltage change in the arc will result in a
high rapid weld current change that instantly "self corrects the
arc length".
E-mail from l. KD - P&F. 12 /07Ed, you would be interested
to know that by the end of the year I will have at least 100 of our
robots welding with US 0.035 (1 mm) wire using conventional spray
transfer with "no pulsing". It took 10 years Ed, but we are finally
using the recommendations you made to us in the nineteen nineties.
I now have the top guy in North America convinced traditional spray
is the way to go with the robot MIG applications. In regards to
your MIG process control training programs and resources we now
have two other plants that will be contacting you.
Note from Ed: This is one of the largest tier one suppliers to
Honda and Toyota in the USA. The plant has hundreds of Panasonic
robots and Panasonic pulsed MIG equipment.
The Panasonic weld equipment and pulsed process was a
requirement of the Japanese parent company. For more than a decade,
this pulsed MIG equipment which should never have ben sent to the
USA, daily generated numerous weld and production issues that
dramatically impacted the daily robot weld quality and production.
With all the problems, the blinkered corporate engineers and
apathetic, inexperienced managers in Japan were reluctant to hear
that the the traditional, more durable, lower cost, North American
CV MIG equipment and logical Swedish robots would provide solutions
to the majority of their daily robot weld issues.
Many Japanese companies are hobbled daily with their Achilles
approach to manufacturing. What is that Achilles heel? It's an
arrogance that what they do is superior to anyone else. Bringing
erratic performing Japanese weld equipment and Japanese MIG wires
to America was like sending second grade coal to Newcastle, UK. The
costly Asian weld wires provided no benefits, the Panasonic weld
equipment was a disaster of inconsistency and erratic performance
of the Panasonic Japanese robots left a lot to be desired.
Thanks to the Japanese general lack of MIG weld process
expertise, their lack of flexibility to make changes when change
was required and there disregard of the process advice I provided
them 10 years previously, I believe this company has wasted at
least 20 million dollars in robot down time, rejects and rework.
But I suppose the important thing is the Japanese engineering egos
are still intact.
Dont forget the influence of the spray weld gasON THE STABiITY
OF SPRAY TRANSFER WELDS.Click here for Ed'sMIG Gas Mixes
GAS MIXES CAN PROVIDE A GREAT CONTRIBUTION TO WELD STABILITY
& WELD ENERGY
In a time of equipment electronic bells and whistles, please
remember with MIG gas mixes, that the CO2 gas dissociation and
oxidation properties, are often not given the credit or
consideration they deserve. Ed introduced 4 important gas mixes in
North America and recommends you visit the MIG gas section of this
site.
The Japanese will often add electronics to MIG welding
equipmentwithout understanding why they added the electronics
E-mail. Oct 2008:I am emailing you because I have come to a
questionable snag with my pulsed MIG equipment. I have the
equipment set in the spray mode. I am welding on5/16 carbon steel
material, my settings are set to spray transfer (29 volts 500 wire
speed in/min).
When making a 3/16 fillet weld with the 0.035 wire I have
noticed that at the end of the weld, the weld flattens out and has
what I have been taught to refer to as a fish eye ( I am not sure
if this is the right term for this problem ).
The attached photo will show you what I am referring to. When
coming to the end of my weld I back over the weld about instead of
just stopping. I dont pull my nozzle away before I let the trigger
go, so I dont think this issue is caused due to the length of the
stick out. My gas is set to 35cfh argon/CO2 mix.Could you please
advise what may be causing this poor finish is this just cosmetic
or an issue that needs to be addressed? If this is an issue that
needs to be addressed could you please explain the proper procedure
for fixing. These parts are under extreme vibrations and some
stresses Vertical / Horizontal and Lateral. Thank you.T Eason.Ed's
Reply. Two things going on here.[1] First the weld picture
indicates poor side wall fusion. As you are using good spray
parameters the lack of fusion is likely a result that the weld
surface was wire brushed, however the mill scale has been left. If
you are concerned about fatique properties you don't MIG weld over
mill scale. Grind the weld area before welding, I am sure you will
see a difference in the weld appearence.
[2] A fish eye is typically a pore evident in a failed weld and
the bright shiny appearence in the pore indicates the presence of
hydrogen, so you dont have a fish eye. You do have a pulsed power
source that has a built in defect. This is a a commom classic issue
with pulsed equipment in which the machine controlled end
parameters or burn back parameters are set too high, (more evidence
that pulsed equipment manufactures don't correctly test the
equipment they build.) I see this defect all the time in pulsed
equipment in robot cells. At the end of the weld, the high voltage
spike applied for the burn back causes a suck back effect in the
arc leaving that classic hole in the crater. In many instances if
you examine with magnification you will find shrinkage cracks
around that hole and with your fatigue concerns, this defect has to
be ground out and the crater filled in. My MIG process control
trainingresources deal with this issue and provide process
solutions, however you would be well served to send the power
source back to the company who manufactured it. It's ironic that
this defect would not occur on a lower cost traditional CV power
source.
THE PULSED MIG PROCESS HAS MORE THAN ONE ACHILLES HEEL: Even
with the world's best pulsed equipment, on many common applications
the Pulsed MIG process will always have its Achilles Heel. Visit
section 2 of pulsed MIG. Find out about useless wave form options
and concerns for lack of weld fusion.
Invest in your weld career, its your choice talk to a salesman
or order Ed'sbooksand MIG and flux cored, manual or robot weld
process control CD training resources.
IF WELD QUALITY IS YOUR FIRST CRITERIA,PULSED MIG WILL NEVER
COMPETE WITHTIP TIG
If you are teaching your self, or providing weld process control
training for others, the following resources are the key to
attaining MIG and flux cored weld process optimization.
Item.1. The Book: "A Management & Engineers Guide To MIG
Weld Quality, Productivity & Costs"
Item 2. A unique robot MIG training or self teaching
resource."Optimum Robot MIG Welds from Weld Process Controls".
Item 3. A unique MIG training or self teaching resource." Manual
MIG Weld Process Optimization from Weld Process Controls".
Item. 4. A unique flux cored training or self teaching
resource."Optimum Manual and Automated Flux Cored Plate and Pipe
welds.
Item 5a."Proceso de Soldadura MIG Manual" (MIG Made Simple. Self
teaching in Spanish)Item 6a. The Self Teaching MIG Book/ Video.
(MIG Made Simple in English).
Note: Items 2-3-4 are the most comprehensive process control,
self teaching and trainingprograms ever developed..Visit Ed's MIG /
flux cored process control books and CD trainingresources.
Pulsed Section 2.
[] Take a look at the Panasonic Ripple Farce.
[] This tractor mfg paid extra when they took their advice
from